Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Priority
Acknowledgment is made of applicant’s claim for foreign priority under 35 U.S.C. 119 (a)-(d). The certified copy has been filed in parent Application No. JP2022-112435, filed on 07/13/2022.
Claim Interpretation
The following is a quotation of 35 U.S.C. 112(f):
(f) Element in Claim for a Combination. – An element in a claim for a combination may be expressed as a means or step for performing a specified function without the recital of structure, material, or acts in support thereof, and such claim shall be construed to cover the corresponding structure, material, or acts described in the specification and equivalents thereof.
The following is a quotation of pre-AIA 35 U.S.C. 112, sixth paragraph:
An element in a claim for a combination may be expressed as a means or step for performing a specified function without the recital of structure, material, or acts in support thereof, and such claim shall be construed to cover the corresponding structure, material, or acts described in the specification and equivalents thereof.
The claims in this application are given their broadest reasonable interpretation using the plain meaning of the claim language in light of the specification as it would be understood by one of ordinary skill in the art. The broadest reasonable interpretation of a claim element (also commonly referred to as a claim limitation) is limited by the description in the specification when 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, is invoked.
As explained in MPEP § 2181, subsection I, claim limitations that meet the following three-prong test will be interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph:
(A) the claim limitation uses the term “means” or “step” or a term used as a substitute for “means” that is a generic placeholder (also called a nonce term or a non-structural term having no specific structural meaning) for performing the claimed function;
(B) the term “means” or “step” or the generic placeholder is modified by functional language, typically, but not always linked by the transition word “for” (e.g., “means for”) or another linking word or phrase, such as “configured to” or “so that”; and
(C) the term “means” or “step” or the generic placeholder is not modified by sufficient structure, material, or acts for performing the claimed function.
Use of the word “means” (or “step”) in a claim with functional language creates a rebuttable presumption that the claim limitation is to be treated in accordance with 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph. The presumption that the claim limitation is interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, is rebutted when the claim limitation recites sufficient structure, material, or acts to entirely perform the recited function.
Absence of the word “means” (or “step”) in a claim creates a rebuttable presumption that the claim limitation is not to be treated in accordance with 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph. The presumption that the claim limitation is not interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, is rebutted when the claim limitation recites function without reciting sufficient structure, material or acts to entirely perform the recited function.
Claim limitations in this application that use the word “means” (or “step”) are being interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, except as otherwise indicated in an Office action. Conversely, claim limitations in this application that do not use the word “means” (or “step”) are not being interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, except as otherwise indicated in an Office action.
This application includes one or more claim limitations that do not use the word “means,” but are nonetheless being interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, because the claim limitation(s) uses a generic placeholder that is coupled with functional language without reciting sufficient structure to perform the recited function and the generic placeholder is not preceded by a structural modifier. Such claim limitation(s) is/are:
“Work operation unit”
The limitation “work operation unit” in Claims 1–3, and as incorporated into Claims 4 and 5, is interpreted under § 112(f).
Although the limitation does not use the term “means,” the presumption against application of § 112(f) is overcome because “unit” is a generic placeholder and “work operation” identifies the element by its intended function rather than by a definite structural class. The additional recitation of an “ON operation performed by a user” describes how the element is operated but does not identify the particular structure that performs the function.
The claimed function is:
“instructs driving of the work implement by an ON operation performed by a user.”
The corresponding structure is work drive switch 33, its associated switching circuitry and connection to control device 40, and equivalents thereof. The specification discloses that work drive switch 33 is operated by the user, instructs driving of lawn mowing device 18 when operated ON, and instructs stopping when operated OFF. See [0031], [0041], and [0062].
The specification therefore discloses sufficient corresponding structure for the claimed function.
“Traveling operation unit”
The limitation “traveling operation unit” in Claims 1 and 2, and as incorporated into Claim 4, is interpreted under § 112(f).
Although the limitation does not use the term “means,” the presumption against application of § 112(f) is overcome because “unit” is a generic placeholder and “traveling operation” describes the functions performed rather than sufficiently definite structure.
The claimed function is:
“instructs forward traveling, backward traveling, and stopping of the work vehicle by an operation performed by the user.”
The corresponding structure is left and right operation levers 22 and 23, left and right lever sensors 50 and 51, their associated signal connections to control device 40, and equivalents thereof.
The specification discloses that forward movement of each operation lever instructs forward rotation of the corresponding traveling motor, rearward movement instructs backward rotation, and movement to the neutral position instructs stopping. See [0031] and [0033]–[0034].
In Claim 5, the traveling operation units are expressly limited to “two operation levers.” The expressly recited operation levers provide definite structure and are not interpreted under § 112(f).
“Control device”
The limitation “control device” in Claims 1–3, and as incorporated into Claims 4 and 5, is interpreted under § 112(f).
Although the limitation does not use the term “means,” the presumption against application of § 112(f) is overcome because “device” is used as a generic placeholder and the claims define the element principally by the control functions it performs. The claims do not otherwise recite a processor, memory, control circuitry, or other definite structure for performing those functions.
Because the recited functions are computer-implemented, the corresponding structure is control device 40, including the disclosed arithmetic unit or CPU, storage unit or memory, microcomputer, determination units 41–44, 47, and 48, work control unit 45, traveling control unit 46, and the disclosed algorithms programmed into that structure, together with equivalents thereof. See [0045] and [0050]–[0054] and Figures 3, 4A, and 4B.
The corresponding algorithms are identified below.
Work-implement control
For controlling driving of the work implement in accordance with operation of the work operation unit, the algorithm:
determines whether work drive switch 33 is ON;
determines whether implement operation is permitted under the current travel and backward-work-permission conditions; and
controls deck inverter 88 and deck motors 60 to drive, stop, or maintain the stopped condition of lawn mowing device 18.
See [0041], [0043], [0050], and [0066]–[0071]; Figure 7, steps S10 and S20–S25.
Vehicle-travel control
For controlling traveling of the work vehicle in accordance with operation of the traveling operation unit or operation levers, the algorithm:
receives detection signals from lever sensors 50 and 51;
determines the respective positions of operation levers 22 and 23;
sets the target rotation directions and speeds of traveling motors 30 and 31; and
independently controls traveling motors 30 and 31 through traveling inverters 84 and 86.
See [0033]–[0034], [0047], and [0052]–[0053].
Reverse-triggered implement stopping
For forcibly stopping the work implement during unauthorized backward travel, the algorithm:
determines whether work drive switch 33 is ON;
determines whether backward work permission switch 34 is OFF;
determines whether the vehicle is traveling backward; and
stops or maintains the stopped condition of lawn mowing device 18.
See [0054], [0059]–[0060], and [0066]–[0069]; Figures 7–8, steps S10–S20.
Continued stopping after backward travel
For the function in Claim 1 of forcibly stopping the work implement both while the vehicle is traveling backward and when the vehicle shifts from backward travel to a stopped state, the algorithm:
stops lawn mowing device 18 during unauthorized backward travel; and
continues the stopped condition when the vehicle transitions from backward travel to the subsequent stopped state.
See [0059] and [0063]–[0064] and Figure 6.
OFF-to-ON restart control
For the additional functions recited in Claims 2 and 4, the algorithm:
maintains the stopped condition of lawn mowing device 18 after backward travel ends;
detects that work drive switch 33 has been shifted from ON to OFF;
detects a subsequent OFF-to-ON operation of work drive switch 33; and
restarts lawn mowing device 18 only after those conditions are satisfied.
See [0060], [0064]–[0066], and [0070]–[0073]; Figures 6–7, steps S12 and S21–S24.
Wheel-based backward-travel determination
For the additional functions recited in Claims 3 and 5, the algorithm:
receives left and right motor-speed signals;
determines whether both wheels rotate in the backward direction at step S14;
determines whether the average speed of the two wheels is equal to or higher than the predetermined value in the backward direction at step S15;
determines backward travel when an applicable criterion is satisfied at step S18; and
forcibly stops or maintains the stopped condition of lawn mowing device 18 at step S20.
See [0054]–[0056] and [0066]–[0072] and Figures 7–8.
For pending Claim 3, “both when” is construed as requiring the control device to provide both recited stopping capabilities: stopping when the two wheels are determined to rotate backward and stopping when the average-speed criterion is satisfied. The language does not require the two determinations to occur simultaneously. This interpretation is consistent with the separate determinations disclosed at steps S14 and S15 and the resulting backward-travel determination at step S18.
The specification discloses sufficient corresponding structure and algorithms for each recited function.
Because this/these claim limitation(s) is/are being interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, it/they is/are being interpreted to cover the corresponding structure described in the specification as performing the claimed function, and equivalents thereof.
If applicant does not intend to have this/these limitation(s) interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, applicant may: (1) amend the claim limitation(s) to avoid it/them being interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph (e.g., by reciting sufficient structure to perform the claimed function); or (2) present a sufficient showing that the claim limitation(s) recite(s) sufficient structure to perform the claimed function so as to avoid it/them being interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph.
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
Claims 1-5 are rejected under 35 U.S.C. 103 as being unpatentable over Heal (US 6109010 A), in view of Wyatt (US 20090065273 A1).
Regarding Claim 1,
Claim 1 is rejected under 35 U.S.C. §103 as being unpatentable over Heal in view of Wyatt.
Disclosure by Heal
Heal discloses:
1. A control system
See at least:
“Referring now to FIG. 2, a state diagram illustrates the operational states of the mowing vehicle 10 according to the present invention....” (Heal, col. 2, ll. 58–62.)
“Control system 40 further includes a control module 52, a PTO status switch 54, an override switch 56, and a reverse switch 58.” (Heal, col. 3, ll. 61–64.)
Rationale: Heal expressly discloses control system 40, including control module 52 and associated PTO, reverse, and override switches.
2. for a work vehicle
See at least:
“Referring first to FIG. 1, a lawn mowing vehicle 10 is shown in perspective view.” (Heal, col. 2, ll. 24–26.)
Rationale: Heal’s lawn-mowing vehicle 10 is a work vehicle because it travels while performing the work of cutting vegetation.
3. that includes a work implement,
See at least:
“A powered implement is carried by the lawn mower 10 and may include a cutting unit 18 having a cutting deck 20 enclosing one or more rotatable cutting blades 22.” (Heal, col. 2, ll. 27–31.)
Rationale: Heal expressly identifies cutting unit 18 as a powered implement carried by the vehicle. Cutting unit 18 corresponds to the claimed work implement.
4. the control system comprising:
See at least:
“Control system 40 further includes a control module 52, a PTO status switch 54, an override switch 56, and a reverse switch 58.” (Heal, col. 3, ll. 61–64.)
Rationale: Heal expressly discloses that control system 40 comprises a control module and several operator and vehicle-condition switches.
5. a work operation unit
See at least:
“The power transfer for the cutting unit 18 operation may be selectively activated by the operator through a PTO switch 54, for example.” (Heal, col. 2, ll. 42–45.)
Rationale: PTO switch 54 constitutes the claimed work operation unit because it is the operator interface used to request operation of cutting unit 18.
6. that instructs driving of the work implement
See at least:
“PTO switch 54 may be a PTO status switch indicating power to the cutting unit 18 or a switch for an electric PTO clutch.” (Heal, col. 2, ll. 45–47.)
Rationale: Operation of PTO switch 54 provides the control instruction that causes power to be supplied to cutting unit 18.
7. by an ON operation performed by a user;
See at least:
“PTO switch 80 is user actuatable and includes a PTO ON and PTO OFF position.” (Heal, col. 5, ll. 4–6.)
“The PTO switch 80 for engaging the cutting unit 18 may then be activated.” (Heal, col. 6, ll. 43–45.)
Rationale: Heal expressly discloses a user-actuatable PTO switch having an ON position. Placing that switch in the ON position requests engagement and operation of the cutting unit.
8. a traveling operation unit
See at least:
“Tractive and directional operation of the vehicle 10 is controlled by the operator by hand controls, foot controls, and a steering wheel 24.” (Heal, col. 2, ll. 30–33.)
Rationale: Heal’s hand controls and foot controls constitute one or more traveling operation units through which the user directs vehicle travel.
9. that instructs forward traveling, backward traveling, and stopping of the work vehicle
See at least:
“Operating conditions of the vehicle 10 include forward motion, neutral, reverse motion....” (Heal, col. 2, ll. 56–58.)
“Condition states for the mower 10 direction of movement are forward, neutral and reverse condition.” (Heal, col. 3, ll. 1–4.)
Rationale: Heal expressly identifies forward, reverse, and neutral conditions selected through the vehicle’s traveling controls. Neutral corresponds to the vehicle’s stopped travel condition.
10. by an operation performed by the user;
See at least:
“Tractive and directional operation of the vehicle 10 is controlled by the operator by hand controls, foot controls, and a steering wheel 24.” (Heal, col. 2, ll. 30–33.)
“[T]he operator shifts from neutral to reverse direction....” (Heal, col. 3, ll. 34–36.)
Rationale: Heal expressly attributes the selection of vehicle travel direction to the operator’s manipulation of the hand or foot controls.
11. a control device
See at least:
“Referring to FIG. 4, the control system 40 includes the control module 52 which is operatively coupled to the PTO status switch 54, the override switch 56, the reverse switch 58, and the kill relay 60.” (Heal, col. 4, ll. 49–52.)
Rationale: Control module 52 receives switch-condition information and controls the engine or PTO circuit. It therefore constitutes the claimed control device.
12. that controls driving of the work implement in accordance with the operation of the work operation unit,
See at least:
“PTO switch status 54 includes an on position and an off position, corresponding to engaging and disengaging the cutting unit 18 of the vehicle 10 through known mechanisms....” (Heal, col. 4, ll. 24–27.)
“The PTO clutch 90 is activated when current flows through path B+-H-I-P-Ground. The PTO clutch 90 is deactivated upon any break in this current path. The control module 82 breaks the current path....” (Heal, col. 6, ll. 47–52.)
Rationale: Heal’s control module engages or disengages the PTO circuit in response to the ON or OFF condition of the PTO switch. The control module therefore controls driving of cutting unit 18 in accordance with operation of the work operation unit.
13. and forcibly stops the work implement when the work vehicle travels backward; and
See at least:
“[T]he control system 40 dictates that the next state will be either the engine 28 non-operating state 5, or the cutting unit 18 disengaged state 7, both states 5 and 7 preventing further operation of the cutting unit 18 while in the reverse direction.” (Heal, col. 3, ll. 35–39.)
Rationale: In the absence of an override, Heal affirmatively causes either engine shutdown or PTO disengagement upon entry into reverse. Either control action forcibly stops the cutting unit while the vehicle travels backward.
14. a backward work permission switch
See at least:
“An override condition ... may be selectively activated by a switch 34 with a removable key to permit cutting operations while traveling in reverse.” (Heal, col. 2, ll. 47–50.)
Rationale: Override switch 34 or 56 permits operation of the cutting unit during reverse travel and therefore constitutes a backward work permission switch.
15. that disables forced stopping of the work implement
See at least:
“[U]nder an override condition, the next state upon the operator shifting from neutral to reverse will be the cutting unit 18 engaged state 6 which permits the cutting unit 18 to remain engaged....” (Heal, col. 3, ll. 39–43.)
Rationale: Activating Heal’s override prevents the engine-kill or PTO-disengagement response that otherwise occurs upon entry into reverse. The override therefore disables the forced stopping of the cutting unit.
16. at a start of backward traveling of the work vehicle
See at least:
“[U]nder an override condition, the next state upon the operator shifting from neutral to reverse will be the cutting unit 18 engaged state 6....” (Heal, col. 3, ll. 39–43.)
Rationale: The override changes the control-system response at the transition from neutral into reverse, which corresponds to the start of backward traveling.
17. by the ON operation performed by the user,
See at least:
“Override switch 56 ... selectively creates a current path ... in response to the operator actuating the override switch 56.” (Heal, col. 4, ll. 32–38.)
“The override mode may be entered by actuating the override switch 56 through its removable key 57.” (Heal, col. 5, ll. 40–43.)
Rationale: Heal expressly discloses that the user affirmatively actuates the override switch to establish the override condition. This actuation corresponds to operating the backward work permission switch ON.
18. wherein
See at least:
“At this point, two modes of vehicle 10 operation may then be entered. The first, a non-override mode.... Additionally a second mode, an override mode of operation....” (Heal, col. 5, ll. 28–37.)
Rationale: Heal discloses the following claimed operational relationships through its alternative override and non-override operating modes.
19. in a case where the backward work permission switch is operated ON
See at least:
“The override mode may be entered by actuating the override switch 56 through its removable key 57.” (Heal, col. 5, ll. 40–43.)
Rationale: Actuation of override switch 56 establishes the claimed condition in which the backward work permission switch is operated ON.
20. and the work operation unit is operated ON,
See at least:
“In this preferred embodiment, the override mode of operation is available only after the PTO switch 80 transitions from its OFF position to its ON position.” (Heal, col. 6, ll. 59–62.)
Rationale: Heal expressly conditions the reverse-operation override on the PTO switch having been placed in its ON position.
21. the control device drives the work implement when the work vehicle travels backward
See at least:
“[A]n override mode of operation, permits the cutting unit 18 to remain engaged even after the vehicle 10 is placed in a reverse direction condition.... The override mode of operation thus permits mowing while the machine 10 is traveling in reverse.” (Heal, col. 5, ll. 35–41.)
Rationale: When both the override and PTO conditions are active, Heal’s control system maintains the cutting-unit drive circuit while the vehicle travels backward.
22. and, in a case where the backward work permission switch is operated OFF
See at least:
“The first, a non-override mode, permits the cutting unit 18 to remain engaged so long as the vehicle 10 remains in a forward gear ... or in neutral....” (Heal, col. 5, ll. 29–33.)
Rationale: Heal’s non-override mode corresponds to the claimed condition in which the backward work permission switch is OFF.
23. and the work operation unit is operated ON,
See at least:
“If the vehicle 10 is under the non-override mode of operation and is then placed in reverse, the engine 28 and cutting unit 18 will be deactivated by operation of the control system 40....” (Heal, col. 5, ll. 33–36.)
Rationale: Heal’s reverse cutoff is triggered when cutting operations have commenced through operation of the PTO switch and the vehicle subsequently enters reverse without an override.
24. the control device forcibly stops the work implement
See at least:
“[T]he engine 28 and cutting unit 18 will be deactivated by operation of the control system 40....” (Heal, col. 5, ll. 33–36.)
“The control module 82 breaks the current path ... when the reverse switch 84 is opened in a non-override condition.” (Heal, col. 6, ll. 50–54.)
Rationale: Heal’s control module affirmatively interrupts the implement-driving circuit or shuts down the engine. That controlled deactivation constitutes forcibly stopping the work implement.
25. both when the work vehicle is traveling backward
See at least:
“[T]he vehicle 10 in the non-override mode is prevented from cutting unit 18 engagement during reverse travel....” (Heal, col. 7, ll. 7–10.)
Rationale: Heal expressly maintains the cutting unit in a deactivated state during reverse travel when reverse-work permission has not been provided.
Claim Limitations Not Explicitly Disclosed by Heal
Heal does not explicitly disclose:
controls traveling of the work vehicle in accordance with the operation of the traveling operation unit,
and when the work vehicle is shifted from a backward traveling state to a stop state.
Examiner Note: Heal’s control module controls the engine or PTO safety circuit, but the reference does not clearly establish that this same device controls forward traveling, backward traveling, and stopping in accordance with the user’s travel-control operation.
Heal also does not reliably disclose continued forced stopping after the vehicle leaves reverse. In Heal’s PTO-clutch embodiment, returning to neutral may reclose reverse switch 84 and restore the PTO circuit while PTO switch 80 remains ON.
Disclosure by Wyatt
Wyatt discloses:
26. controls traveling of the work vehicle in accordance with the operation of the traveling operation unit,
See at least:
“Traction controller 80 controls the speed and direction of vehicle 30.” (Wyatt, [0026].)
“A rocker style accelerator pedal 52 (or other accelerator mechanism) signals traction controller 80 of an operator-directed acceleration or deceleration of vehicle 30 in either the forward or reverse direction. The input signals from accelerator pedal 52 determine the direction and speed of operation of vehicle 30.” (Wyatt, [0030].)
“If accelerator pedal 52 or drive levers 236 have been moved out of the neutral position, the electric motors 41, 241 are started and operated at the respective speed and direction indicated.” (Wyatt, [0044].)
Rationale: Wyatt expressly discloses that the traction controller receives the user’s forward, reverse, acceleration, deceleration, and neutral commands and controls the traction motors accordingly. Wyatt therefore supplies the affirmative relationship between the control device, traveling operation unit, and vehicle travel that is not clearly disclosed by Heal.
27. and when the work vehicle is shifted from a backward traveling state to a stop state.
See at least:
“Any alarm or emergency condition ... encountered by traction controller(s) 80, 220 or deck controller 82, 230 will result in passing control to state 102 and stopping of both the vehicle and the deck blades. If PTO switch 60 was on before entering error state 102, it will be necessary to cycle PTO switch 60 after recovery from the error in order to resume operation of mower deck motors 145, 234.” (Wyatt, [0058].)
“[I]f a reverse cut-off function is selected in the software, then mowing is not allowed (‘105 Opt 2’ in FIG. 10) and a non-recoverable error is generated and control passes to state 102.” (Wyatt, [0059].)
“State 105 is the attempted reverse mowing with ROS off state.... [I]t does not allow any mowing (referenced in FIG. 10 as ‘105 Opt 2—Reverse Cut-Off’) and control is passed to state 102.... If not allowed, and control is passed to state 102 as mentioned above, this is a non-recoverable error, so key switch 58 must be turned off and back on to proceed.” (Wyatt, [0061].)
Rationale: Wyatt expressly discloses persistent reverse-cutoff logic, although it does not recite the exact claimed transition language. With ROS permission OFF and the PTO ON, an attempted reverse-mowing condition passes control to nonrecoverable state 102. State 102 stops the deck blades and retains the cutoff until a separate reset and PTO-switch cycling operation occurs. Returning the travel control to neutral or stopping the vehicle does not automatically restart the deck.
Applying Wyatt’s persistent cutoff state to Heal would cause Heal’s reverse-initiated implement stop to continue when the operator moves the traveling control from reverse to neutral or stop. The claimed continued forced stop during the reverse-to-stop transition would therefore have been the predictable result of using Wyatt’s known persistent interlock logic in Heal.
Motivation to Combine Heal and Wyatt
Therefore, given the teachings as a whole, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention, having Heal and Wyatt before them, to modify Heal’s expressly contemplated software-based control system to include Wyatt’s integrated travel-controller and persistent reverse-cutoff logic.
Heal and Wyatt address the same type of work vehicle and the same reverse-mowing safety problem. Wyatt’s controller-based implementation would predictably allow Heal’s system to control vehicle travel according to operator travel inputs and maintain the cutting-unit cutoff after an unauthorized reverse-mowing condition when the vehicle returns to neutral or stop.
A PHOSITA would have been motivated to make the modification to:
prevent automatic blade reengagement when Heal’s reverse switch recloses;
prevent an unexpected implement restart immediately after reverse travel;
improve operator and bystander safety;
maintain deterministic implement behavior during the reverse-to-stop transition; and
use Wyatt’s known persistent safety-interlock logic for its established purpose.
The modification would not require incorporating Wyatt’s complete electric vehicle bodily into Heal. Heal expressly recognizes that its discrete control circuitry may be implemented as a software-based control system. Heal, col. 7, ll. 21–24. A PHOSITA could therefore incorporate Wyatt’s relevant travel-control and persistent-interlock state logic while retaining Heal’s mower, PTO arrangement, reverse sensor, cutting unit, and reverse-operation override.
Regarding Claim 2,
Disclosure by Heal
Heal discloses:
A control system
See at least:
“Control system 40 further includes a control module 52, a PTO status switch 54, an override switch 56, and a reverse switch 58.” (Heal, p. 5, col. 3, ll. 61–64.)
Rationale: Heal expressly discloses control system 40, including control module 52 and the PTO, override, and reverse switches through which the system controls the vehicle engine and cutting unit.
for a work vehicle
See at least:
“Referring first to FIG. 1, a lawn mowing vehicle 10 is shown in perspective view.” (Heal, p. 4, col. 2, ll. 24–26.)
Rationale: Heal’s lawn-mowing vehicle 10 is a work vehicle because it is configured to travel while performing vegetation-cutting work.
that includes a work implement,
See at least:
“A powered implement is carried by the lawn mower 10 and may include a cutting unit 18 having a cutting deck 20 enclosing one or more rotatable cutting blades 22.” (Heal, p. 4, col. 2, ll. 27–31.)
Rationale: Heal expressly identifies cutting unit 18 as a powered implement carried by the vehicle. Cutting unit 18 therefore constitutes the claimed work implement.
the control system comprising:
See at least:
“Control system 40 further includes a control module 52, a PTO status switch 54, an override switch 56, and a reverse switch 58.” (Heal, p. 5, col. 3, ll. 61–64.)
Rationale: Heal expressly discloses that its control system comprises a control module and associated PTO, reverse, and override switches.
a work operation unit
See at least:
“The power transfer for the cutting unit 18 operation may be selectively activated by the operator through a PTO switch 54, for example.” (Heal, p. 4, col. 2, ll. 42–45.)
Rationale: Heal’s PTO switch 54 is the operator interface used to request powered operation of cutting unit 18 and therefore constitutes the claimed work operation unit.
that instructs driving of the work implement
See at least:
“PTO switch 54 may be a PTO status switch indicating power to the cutting unit 18 or a switch for an electric PTO clutch.” (Heal, p. 4, col. 2, ll. 45–47.)
Rationale: Operation of PTO switch 54 supplies the command that causes power to be transferred through the PTO arrangement to cutting unit 18. It therefore instructs driving of the work implement.
by an ON operation performed by a user;
See at least:
“PTO switch 80 is user actuatable and includes a PTO ON and PTO OFF position.” (Heal, p. 6, col. 5, ll. 4–6.)
Rationale: Heal expressly discloses that PTO switch 80 is actuated by the user and has an ON position corresponding to engagement of the cutting unit.
a traveling operation unit
See at least:
“Tractive and directional operation of the vehicle 10 is controlled by the operator by hand controls, foot controls, and a steering wheel 24.” (Heal, p. 4, col. 2, ll. 30–33.)
Rationale: Heal’s hand and foot controls constitute a traveling operation unit through which the user provides vehicle-travel instructions.
that instructs forward traveling, backward traveling, and stopping of the work vehicle
See at least:
“Operating conditions of the vehicle 10 include forward motion, neutral, reverse motion....” (Heal, p. 4, col. 2, ll. 56–58.)
“Condition states for the mower 10 direction of movement are forward, neutral and reverse condition.” (Heal, p. 5, col. 3, ll. 1–4.)
Rationale: Heal expressly discloses forward, reverse, and neutral travel conditions. Neutral is the condition in which propulsion in either travel direction is discontinued and therefore corresponds to stopping the work vehicle.
by an operation performed by the user;
See at least:
“Tractive and directional operation of the vehicle 10 is controlled by the operator by hand controls, foot controls, and a steering wheel 24.” (Heal, p. 4, col. 2, ll. 30–33.)
Rationale: Heal expressly attributes the selection of vehicle travel and direction to the operator’s manipulation of the hand and foot controls.
a control device
See at least:
“Referring to FIG. 4, the control system 40 includes the control module 52 which is operatively coupled to the PTO status switch 54, the override switch 56, the reverse switch 58, and the kill relay 60.” (Heal, p. 5, col. 4, ll. 49–52.)
Rationale: Control module 52 receives or responds to PTO, reverse, and override switch conditions and controls the engine or PTO circuit. Control module 52 therefore constitutes the claimed control device.
that controls driving of the work implement in accordance with the operation of the work operation unit,
See at least:
“PTO switch status 54 includes an on position and an off position, corresponding to engaging and disengaging the cutting unit 18 of the vehicle 10 through known mechanisms....” (Heal, p. 5, col. 4, ll. 24–27.)
“The PTO clutch 90 is activated when current flows through path B+-H-I-P-Ground. The PTO clutch 90 is deactivated upon any break in this current path. The control module 82 breaks the current path....” (Heal, p. 6, col. 6, ll. 47–52.)
Rationale: Heal’s control module establishes or interrupts the PTO-clutch circuit according to the ON or OFF operation of the PTO switch. It therefore controls driving of cutting unit 18 in accordance with operation of the work operation unit.
and forcibly stops the work implement when the work vehicle travels backward; and
See at least:
“[T]he control system 40 dictates that the next state will be either the engine 28 non-operating state 5, or the cutting unit 18 disengaged state 7, both states 5 and 7 preventing further operation of the cutting unit 18 while in the reverse direction.” (Heal, p. 5, col. 3, ll. 35–39.)
Rationale: Heal expressly discloses that, in the absence of an override, the control system responds to reverse travel by shutting down the engine or disengaging the cutting unit. Either affirmative control action forcibly stops the work implement while the vehicle travels backward.
a backward work permission switch
See at least:
“An override condition ... may be selectively activated by a switch 34 with a removable key to permit cutting operations while traveling in reverse.” (Heal, p. 4, col. 2, ll. 47–50.)
Rationale: Heal’s override switch selectively permits cutting-unit operation during reverse travel and therefore constitutes a backward work permission switch.
that disables forced stopping of the work implement
See at least:
“[U]nder an override condition, the next state upon the operator shifting from neutral to reverse will be the cutting unit 18 engaged state 6 which permits the cutting unit 18 to remain engaged....” (Heal, p. 5, col. 3, ll. 39–43.)
Rationale: Activating Heal’s override prevents the engine-kill or cutting-unit-disengagement response that would otherwise occur upon entry into reverse. The override therefore disables the forced stopping of the cutting unit.
at a start of backward traveling of the work vehicle
See at least:
“[U]nder an override condition, the next state upon the operator shifting from neutral to reverse will be the cutting unit 18 engaged state 6....” (Heal, p. 5, col. 3, ll. 39–43.)
Rationale: Heal applies the override when the operator shifts the vehicle from neutral into reverse. That transition constitutes the start of backward traveling.
by the ON operation performed by the user,
See at least:
“Override switch 56 ... selectively creates a current path ... in response to the operator actuating the override switch 56.” (Heal, p. 5, col. 4, ll. 32–38.)
Rationale: Heal expressly requires affirmative user actuation of override switch 56 to establish the override condition. Such actuation corresponds to operating the backward work permission switch ON.
wherein
See at least:
“At this point, two modes of vehicle 10 operation may then be entered. The first, a non-override mode.... Additionally a second mode, an override mode of operation....” (Heal, p. 6, col. 5, ll. 28–37.)
Rationale: Heal expressly discloses the following operational relationships through its alternative override and non-override operating modes.
in a case where the backward work permission switch is operated ON
See at least:
“The override mode may be entered by actuating the override switch 56 through its removable key 57.” (Heal, p. 6, col. 5, ll. 40–43.)
Rationale: Actuation of override switch 56 establishes the condition in which the backward work permission switch is operated ON.
and the work operation unit is operated ON,
See at least:
“In this preferred embodiment, the override mode of operation is available only after the PTO switch 80 transitions from its OFF position to its ON position.” (Heal, p. 6, col. 6, ll. 59–62.)
Rationale: Heal expressly discloses that reverse-work permission is established in connection with the PTO switch being placed in its ON position.
the control device drives the work implement when the work vehicle travels backward,
See at least:
“[A]n override mode of operation, permits the cutting unit 18 to remain engaged even after the vehicle 10 is placed in a reverse direction condition.... The override mode of operation thus permits mowing while the machine 10 is traveling in reverse.” (Heal, p. 6, col. 5, ll. 35–41.)
Rationale: When the override condition and PTO ON condition are present, Heal’s control system maintains the cutting-unit drive circuit while the vehicle travels backward.
in a case where the backward work permission switch is operated OFF
See at least:
“The first, a non-override mode, permits the cutting unit 18 to remain engaged so long as the vehicle 10 remains in a forward gear ... or in neutral....” (Heal, p. 6, col. 5, ll. 29–33.)
Rationale: Heal’s non-override mode corresponds to the claimed condition in which the backward work permission switch is operated OFF.
and the work operation unit is operated ON,
See at least:
“Cutting operations may commence after the user selectively actuates the PTO status switch 54 to engage the cutting unit 18.” (Heal, p. 6, col. 5, ll. 27–29.)
Rationale: Heal’s reverse-cutoff sequence begins from a condition in which the user has actuated the PTO switch to engage the cutting unit. The work operation unit is therefore ON before the unauthorized reverse condition occurs.
the control device forcibly stops the work implement
See at least:
“If the vehicle 10 is under the non-override mode of operation and is then placed in reverse, the engine 28 and cutting unit 18 will be deactivated by operation of the control system 40....” (Heal, p. 6, col. 5, ll. 33–36.)
Rationale: Heal’s control system affirmatively shuts down the engine or disengages the cutting unit in response to the unauthorized reverse condition. That affirmative deactivation constitutes forcibly stopping the work implement.
when the work vehicle travels backward,
See at least:
“[T]he vehicle 10 in the non-override mode is prevented from cutting unit 18 engagement during reverse travel....” (Heal, p. 7, col. 7, ll. 7–10.)
Rationale: Heal expressly maintains the cutting unit in a deactivated condition during reverse travel when the override has not been activated.
Claim Limitations Not Explicitly Disclosed by Heal
Heal does not explicitly disclose the following claim limitations:
controls traveling of the work vehicle in accordance with the operation of the traveling operation unit,
and after forcibly stopping the work implement,
the control device drives the work implement
only when the work vehicle finishes backward traveling
and the work operation unit is shifted to an OFF operation
and then is shifted to an ON operation again.
Examiner Note: Heal discloses user-operated travel controls but does not clearly disclose that the claimed control device affirmatively controls forward travel, backward travel, and stopping in accordance with those controls.
Heal also does not disclose the claimed persistent reverse cutoff followed by a mandatory PTO OFF-to-ON reset. In Heal’s PTO-clutch embodiment, returning from reverse may reclose reverse switch 84 and restore the PTO-clutch circuit without requiring the user to cycle the PTO switch.
Disclosure by Wyatt
Wyatt discloses:
controls traveling of the work vehicle in accordance with the operation of the traveling operation unit,
See at least:
“Traction controller 80 controls the speed and direction of vehicle 30.” (Wyatt, [0026].)
“A rocker style accelerator pedal 52 (or other accelerator mechanism) signals traction controller 80 of an operator-directed acceleration or deceleration of vehicle 30 in either the forward or reverse direction. The input signals from accelerator pedal 52 determine the direction and speed of operation of vehicle 30.” (Wyatt, [0030].)
Rationale: Wyatt expressly discloses that traction controller 80 receives operator-directed travel inputs and controls vehicle speed, forward direction, reverse direction, deceleration, and stopping accordingly. Wyatt therefore supplies the affirmative control-device relationship not clearly disclosed by Heal.
and after forcibly stopping the work implement,
See at least:
“If traction controller(s) 80, 220 determines it should pass control to state 105 (attempted reverse mowing with ROS off) ... if a reverse cut-off function is selected in the software, then mowing is not allowed (‘105 Opt 2’ in FIG. 10) and a non-recoverable error is generated and control passes to state 102.” (Wyatt, [0059].)
“Any alarm or emergency condition ... will result in passing control to state 102 and stopping of both the vehicle and the deck blades.” (Wyatt, [0058].)
Rationale: Wyatt expressly discloses a sequence in which attempted reverse mowing without reverse-operation permission causes the controller to stop the deck blades and then retain control in error state 102. The subsequent control behavior therefore occurs after the work implement has been forcibly stopped.
the control device drives the work implement
See at least:
“If PTO switch 60 was on before entering error state 102, it will be necessary to cycle PTO switch 60 after recovery from the error in order to resume operation of mower deck motors 145, 234.” (Wyatt, [0058].)
Rationale: Wyatt expressly discloses that the deck motors can resume operation under controller command after recovery and the required PTO-switch cycle. Resuming operation of mower deck motors 145 and 234 constitutes the control device driving the work implement.
only when the work vehicle finishes backward traveling
See at least:
“State 105 is the attempted reverse mowing with ROS off state.... [I]t does not allow any mowing (referenced in FIG. 10 as ‘105 Opt 2—Reverse Cut-Off’) and control is passed to state 102....” (Wyatt, [0061].)
“Functionality of traction controller(s) 80, 220 is checked, the neutral state of the vehicle is verified, and the drive state is enabled. The inactive state of PTO switch 60 ... is also verified.” (Wyatt, [0043].)
Rationale: Wyatt expressly prevents mowing while the unauthorized reverse condition exists. Wyatt further verifies that the vehicle has returned to neutral and that the PTO is inactive before enabling normal drive operation. Thus, after the reverse cutoff, the controller does not permit renewed implement operation while the vehicle remains in the unauthorized reverse state.
To the extent Wyatt does not expressly describe the entire recovery sequence in a single paragraph, requiring termination of reverse travel before permitting recovery would have been obvious to a PHOSITA. Wyatt identifies reverse travel without ROS permission as the condition causing the cutoff. It would have been contrary to Wyatt’s safety purpose to permit the cutting unit to restart while that same prohibited reverse condition remained present. Removal of the reverse condition is therefore an express or, at minimum, PHOSITA-obvious prerequisite to restoring cutting operation.
and the work operation unit is shifted to an OFF operation
See at least:
“If PTO switch 60 was on before entering error state 102, it will be necessary to cycle PTO switch 60 after recovery from the error in order to resume operation of mower deck motors 145, 234.” (Wyatt, [0058].)
“When PTO switch 60 is switched off ... deck controller 82, 230 jumps to state 202 from state 205.” (Wyatt, [0071].)
Rationale: Wyatt expressly requires cycling PTO switch 60 before deck-motor operation can resume. The first required part of that cycle is moving PTO switch 60 from its existing ON condition to its OFF condition. Paragraph [0071] confirms that switching the PTO control OFF moves the deck controller out of the PTO-disabled state.
and then is shifted to an ON operation again.
See at least:
“If PTO switch 60 was on before entering error state 102, it will be necessary to cycle PTO switch 60 after recovery from the error in order to resume operation of mower deck motors 145, 234.” (Wyatt, [0058].)
“In state 202, deck controller 82, 230 is enabled with key switch 58 on and PTO switch 60 off. When PTO switch 60 is switched on, deck controller 82, 230 jumps to state 203.” (Wyatt, [0068].)
“In state 203, deck controller 82, 230 is enabled with key switch 58 on and PTO switch 60 on to power mower deck motors 145, 234.” (Wyatt, [0069].)
Rationale: Wyatt expressly discloses that, after the PTO switch is moved OFF, the operator must move it back ON to enter state 203 and power the deck motors. Wyatt therefore supplies the claimed OFF-to-ON reset sequence as a prerequisite to renewed implement operation.
Motivation to Combine Heal and Wyatt
Therefore, given the teachings as a whole, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention, having Heal and Wyatt before them, to implement Wyatt’s integrated travel-controller and persistent reverse-cutoff reset logic in Heal’s mowing-vehicle control system so that: (1) the controller controls vehicle travel in accordance with operator travel-control inputs; and (2) after the cutting unit has been stopped because reverse mowing was attempted without permission, the cutting unit remains disabled until the vehicle is no longer traveling backward and the operator deliberately cycles the PTO switch from ON to OFF and then back to ON.
Heal and Wyatt address the same type of powered work vehicle and the same reverse-mowing safety problem. Both systems monitor the PTO condition, vehicle direction, and a user-operated reverse-mowing permission control. Their teachings are therefore technically compatible and complementary.
Heal expressly recognizes that its discrete electrical control system may be implemented using software. Wyatt supplies a known software-state implementation in which an unauthorized reverse-mowing condition stops the deck blades, retains the cutoff condition, and requires a deliberate PTO-switch cycle before blade operation can resume. Applying Wyatt’s recovery logic to Heal would have been a predictable use of known safety-interlock logic according to its established function.
A PHOSITA would have been motivated to make the modification because Heal’s PTO-clutch embodiment may otherwise reenergize the cutting unit automatically when the vehicle leaves reverse and the reverse switch recloses while the PTO switch remains ON. Wyatt’s required OFF-to-ON reset would:
prevent unintended automatic blade restart;
require an affirmative user decision before cutting resumes;
confirm that the reverse condition has ended;
improve operator and bystander safety;
provide deterministic recovery from the reverse cutoff; and
improve the reliability of Heal’s reverse-operation interlock.
The modification would not require bodily incorporation of Wyatt’s entire electric vehicle into Heal. A PHOSITA would incorporate Wyatt’s relevant controller and state-machine logic into Heal’s expressly contemplated software-based implementation while retaining Heal’s mower, PTO arrangement, reverse detector, override switch, and cutting unit.
Regarding Claim 3,
Disclosure by Heal
Heal discloses:
A control system
See at least: “Control system 40 further includes a control module 52, a PTO status switch 54, an override switch 56, and a reverse switch 58.” (Heal, p. 5, col. 3, ll. 61–64.)
Rationale: Heal expressly discloses control system 40, including control module 52 and the PTO, override, and reverse switches through which the system controls the engine and cutting unit.
for a work vehicle
See at least: “Referring first to FIG. 1, a lawn mowing vehicle 10 is shown in perspective view.” (Heal, p. 4, col. 2, ll. 24–26.)
Rationale: Heal’s lawn-mowing vehicle 10 is a work vehicle because it travels while performing vegetation-cutting work.
and a work implement,
See at least: “A powered implement is carried by the lawn mower 10 and may include a cutting unit 18 having a cutting deck 20 enclosing one or more rotatable cutting blades 22.” (Heal, p. 4, col. 2, ll. 27–31.)
Rationale: Heal expressly identifies cutting unit 18 as a powered implement carried by the vehicle. Cutting unit 18 therefore functionally constitutes the claimed work implement.
the control system comprising:
See at least: “Control system 40 further includes a control module 52, a PTO status switch 54, an override switch 56, and a reverse switch 58.” (Heal, p. 5, col. 3, ll. 61–64.)
Rationale: Heal expressly identifies components constituting control system 40, including the control module and the PTO, reverse, and override switches.
a work operation unit
See at least: “The power transfer for the cutting unit 18 operation may be selectively activated by the operator through a PTO switch 54, for example.” (Heal, p. 4, col. 2, ll. 42–45.)
Rationale: PTO switch 54 is the operator interface through which powered operation of cutting unit 18 is selected. It therefore functionally constitutes the claimed work operation unit.
that instructs driving of the work implement
See at least: “PTO switch 54 may be a PTO status switch indicating power to the cutting unit 18 or a switch for an electric PTO clutch.” (Heal, p. 4, col. 2, ll. 45–47.)
Rationale: Operation of PTO switch 54 supplies the control input that engages the power-transfer mechanism or electric PTO clutch associated with cutting unit 18. The switch therefore instructs powered driving of the work implement rather than merely indicating an unrelated operating condition.
by an ON operation performed by a user;
See at least: “PTO switch 80 is user actuatable and includes a PTO ON and PTO OFF position.” (Heal, p. 6, col. 5, ll. 4–6.)
Rationale: Heal expressly discloses both user actuation and an ON position. Moving the user-actuatable PTO switch to the ON position requests powered operation of the cutting unit.
a control device
See at least: “Referring to FIG. 4, the control system 40 includes the control module 52 which is operatively coupled to the PTO status switch 54, the override switch 56, the reverse switch 58, and the kill relay 60.” (Heal, p. 5, col. 4, ll. 49–52.)
Rationale: Control module 52 receives or responds to the PTO, override, and reverse-switch conditions and controls the engine-kill or implement-driving circuitry. Control module 52 therefore functionally constitutes the claimed control device.
that controls driving of the work implement in accordance with the operation of the work operation unit,
See at least: “PTO switch status 54 includes an on position and an off position, corresponding to engaging and disengaging the cutting unit 18 of the vehicle 10 through known mechanisms....” (Heal, p. 5, col. 4, ll. 24–27.)
Rationale: The operational state of cutting unit 18 is controlled according to whether PTO switch 54 is placed in its ON or OFF position. Thus, the control system functionally controls driving of the work implement in accordance with operation of the work operation unit.
and forcibly stops the work implement when the work vehicle travels backward; and
See at least: “[T]he control system 40 dictates that the next state will be either the engine 28 non-operating state 5, or the cutting unit 18 disengaged state 7, both states 5 and 7 preventing further operation of the cutting unit 18 while in the reverse direction.” (Heal, p. 5, col. 3, ll. 35–39.)
Rationale: In the non-override condition, Heal’s control system responds to entry into reverse by affirmatively shutting down the engine or disengaging the cutting unit. Either controlled action removes driving power from the cutting unit and therefore forcibly stops the work implement when the vehicle travels backward.
a backward work permission switch
See at least: “An override condition ... may be selectively activated by a switch 34 with a removable key to permit cutting operations while traveling in reverse.” (Heal, p. 4, col. 2, ll. 47–50.)
Rationale: Heal’s override switch selectively authorizes operation of the cutting unit during reverse travel. It therefore performs the function of the claimed backward work permission switch.
that disables forced stopping of the work implement
See at least: “[U]nder an override condition, the next state upon the operator shifting from neutral to reverse will be the cutting unit 18 engaged state 6 which permits the cutting unit 18 to remain engaged....” (Heal, p. 5, col. 3, ll. 39–43.)
Rationale: Activating Heal’s override prevents the engine-shutdown or cutting-unit-disengagement response that would otherwise occur upon reverse travel. The override therefore disables forced stopping of the work implement.
at a start of backward traveling of the work vehicle
See at least: “[U]nder an override condition, the next state upon the operator shifting from neutral to reverse will be the cutting unit 18 engaged state 6....” (Heal, p. 5, col. 3, ll. 39–43.)
Rationale: Heal applies the override to the control-system transition occurring when the operator shifts from neutral into reverse. That neutral-to-reverse transition is the start of backward traveling.
by the ON operation performed by the user,
See at least: “Override switch 56 ... selectively creates a current path ... in response to the operator actuating the override switch 56.” (Heal, p. 5, col. 4, ll. 32–38.)
Rationale: Heal expressly requires affirmative operator actuation of override switch 56 to establish the override condition. This user actuation places the backward-work-permission control in its operative or ON condition.
wherein
See at least: “At this point, two modes of vehicle 10 operation may then be entered. The first, a non-override mode.... Additionally a second mode, an override mode of operation....” (Heal, p. 6, col. 5, ll. 28–37.)
Rationale: Heal expressly discloses the operational relationship that follows through its override and non-override operating modes.
in a case where the backward work permission switch is operated OFF
See at least:
“The first, a non-override mode, permits the cutting unit 18 to remain engaged so long as the vehicle 10 remains in a forward gear ... or in neutral.” (Heal, p. 6, col. 5, ll. 29–33.)
Rationale: Heal’s non-override mode is the functional condition in which reverse-work permission has not been activated and therefore corresponds to the backward work permission switch being operated OFF.
and the work operation unit is operated ON,
See at least: “Cutting operations may commence after the user selectively actuates the PTO status switch 54 to engage the cutting unit 18.” (Heal, p. 6, col. 5, ll. 27–29.)
Rationale: Heal’s reverse-cutoff sequence begins with cutting unit 18 engaged through user actuation of PTO switch 54. Thus, the work operation unit is ON when the non-permitted reverse condition is subsequently detected.
the control device forcibly stops the work implement
See at least: “If the vehicle 10 is under the non-override mode of operation and is then placed in reverse, the engine 28 and cutting unit 18 will be deactivated by operation of the control system 40....” (Heal, p. 6, col. 5, ll. 33–36.)
Rationale:
Heal’s control system affirmatively deactivates the engine and cutting unit in response to an unauthorized reverse condition. This is a controlled cessation of power to the implement and therefore constitutes forcibly stopping the work implement.
Claim Limitations Not Explicitly Disclosed by Heal
Heal does not explicitly disclose the following claim limitations:
that includes two traveling motors at left and right
coupled to two wheels at left and right
and driven independently from each other,
two operation levers
that are arranged separately at left and right of a driver's seat
and each of which instructs a rotation direction and rotation speed of one of the wheels located at a corresponding side
by moving of the corresponding operation lever in a front-rear direction,
controls traveling of the work vehicle in accordance with operations of the two operation levers,
both when it is determined that the two wheels at left and right rotate in a backward direction
and when it is determined that average speed of the two wheels at left and right is equal to or higher than a predetermined value in terms of speed in the backward direction.
Examiner Note: Heal discloses operator-controlled vehicle travel, forward, neutral, and reverse travel states, and a reverse-responsive cutting-unit interlock. Heal does not, however, specifically disclose the claimed independently driven left and right traction arrangement, the corresponding paired operation levers, or determination of reverse travel using both wheel direction and an average rearward-speed threshold.
Disclosure by Wyatt
Wyatt discloses:
that includes two traveling motors at left and right
See at least: “Power supply 238 of vehicle 300 drives an electric motor 341 located on each EPRM 310a and 310b....” (Wyatt, [0036].)
Rationale: Wyatt expressly discloses respective electric traction motors associated with left and right propulsion assemblies. These motors supply the motive power that travels the vehicle and therefore constitute traveling motors at the left and right sides.
coupled to two wheels at left and right
See at least: “[Electric motors 341] in turn drive planetary reduction transmission/gearing 314a and 314b, coupled to axle shafts 313a and 313b, thereby separately driving rear wheels 212a and 212b.” (Wyatt, [0036].)
Rationale: Each traction motor is mechanically coupled through its respective reduction gearing and axle shaft to a corresponding rear wheel. Wyatt therefore expressly discloses the functional motor-to-wheel coupling required by the limitation.
and driven independently from each other,
See at least: “Master traction controller 220a controls transaxle 210a and communicates with slave traction controller 220b.... Slave controller 220b controls transaxle 210b....” (Wyatt, [0037].)
Rationale: The two traction assemblies have respective control channels, with one controller controlling one transaxle and the other controller controlling the other transaxle. The respective motors and wheels can therefore be commanded at different speeds or directions, as required for zero-turn propulsion, and are functionally driven independently from each other.
two operation levers
See at least: “[S]teering interfaces take the form of a right drive lever 236a and a left drive lever 236b....” (Wyatt, [0037].)
Rationale: Wyatt expressly identifies two distinct drive levers: right drive lever 236a and left drive lever 236b.
that are arranged separately at left and right of a driver's seat
See at least: “[S]teering interfaces take the form of a right drive lever 236a and a left drive lever 236b.... Associated with these operator-manipulated drive levers are sensors and switches....” (Wyatt, [0037].)
Rationale: Wyatt expressly distinguishes the interfaces as right and left operator-manipulated drive levers. In Wyatt’s seated zero-turn mowing vehicle, arranging the right and left drive levers on corresponding sides of the operator’s seat would have been understood by a PHOSITA from the disclosed conventional dual-lever steering arrangement and the illustrated vehicle configuration. At minimum, the corresponding left/right placement is the ordinary and predictable arrangement that allows the seated operator to manipulate each lever with the corresponding hand.
and each of which instructs a rotation direction and rotation speed of one of the wheels located at a corresponding side
See at least: “A right drive lever position sensor 291a is associated with the right drive lever ... and is in communication with the master traction controller 290a. Similarly, a left drive lever position sensor 291b is associated with the left drive lever ... and is in communication with the slave traction controller 290b.” (Wyatt, [0039].)
Rationale: Wyatt assigns the right and left drive-lever position signals to the corresponding right and left traction-control channels. Because each controller controls the respective transaxle and driven wheel, each lever instructs the direction and speed of the wheel on its corresponding side. This correspondence is functional, not merely nominal: differential lever positions cause differential wheel commands necessary for propulsion and zero-turn steering.
by moving of the corresponding operation lever in a front-rear direction,
See at least: “Sensors/switches 237a and 237b may be actuated directly by drive levers 236....” (Wyatt, [0037].)
Rationale: Wyatt’s drive-lever position sensors detect displacement of the respective drive levers and provide corresponding propulsion commands. For the disclosed conventional dual-lever zero-turn interface, moving a lever forward or rearward commands the corresponding wheel in the forward or reverse direction, with displacement determining commanded speed. Wyatt therefore expressly or, at minimum, implicitly teaches the claimed front-rear lever movement.
controls traveling of the work vehicle in accordance with operations of the two operation levers,
See at least: “Master traction controller 220a controls transaxle 210a.... Slave controller 220b controls transaxle 210b....” (Wyatt, [0037].); “If accelerator pedal 52 or drive levers 236 have been moved out of the neutral position, the electric motors 41, 241 are started and operated at the respective speed and direction indicated.” (Wyatt, [0044].)
Rationale: Wyatt’s traction controllers receive the respective lever-position signals and operate the corresponding electric propulsion motors at the indicated speed and direction. The controllers therefore affirmatively control vehicle travel in accordance with operations of the two levers.
both when it is determined that the two wheels at left and right rotate in a backward direction
See at least: “In an embodiment employing two traction controllers and two electric transaxles, the reverse mode can be defined as a vehicle travel condition in which either one or both of the electric transaxles are moving in reverse.” (Wyatt, [0073].)
Rationale: Wyatt expressly teaches determining the reverse operating state from the detected directions of the two independently controlled electric transaxles. Wyatt expressly includes the condition in which both transaxles, and consequently both corresponding driven wheels, are moving in reverse. When Wyatt’s reverse cut-off option is selected and reverse mowing is not permitted, determination of that reverse state invokes the blade-stopping safety response.
and when it is determined that average speed of the two wheels at left and right is equal to or higher than a predetermined value in terms of speed in the backward direction.
See at least: “A reverse state of the vehicle can be defined several ways, depending on control architecture and vehicle type.” (Wyatt, [0073].); “In another embodiment, the mode of the vehicle may be defined by the direction of the axle, wheel, tire, etc., having the greater velocity.” (Wyatt, [0073].)
Rationale: Wyatt does not expressly state that the arithmetic average of the two wheel speeds is calculated and compared with a predetermined rearward-speed value. Wyatt nevertheless expressly teaches determining the vehicle’s reverse state from the directions and velocities of the left and right propulsion components and recognizes that different mathematical definitions may be selected depending on the control architecture and vehicle type.
Given Wyatt’s independently controlled left and right traction channels and available wheel or axle speed information, using the average of the two wheel speeds as the representative vehicle speed would have been obvious to a PHOSITA. Averaging the two measured speeds is a conventional and predictable way to estimate the translational speed of a differential-drive or zero-turn vehicle while reducing the effect of unequal wheel speeds during steering.
It also would have been obvious to compare that representative rearward speed with a predetermined value before invoking the forced implement stop. A threshold comparison avoids treating sensor noise, control deadband, or insignificant wheel creep near neutral as meaningful backward travel. The modification would use Wyatt’s already available left and right speed values for their established purpose—determining the vehicle’s operating state—and would merely select a known representative-speed calculation and threshold decision rule.
Functionally, the resulting controller would determine: (1) whether both driven wheels are rotating in the backward direction; and (2) whether their average rearward speed has reached the stored cutoff threshold. When reverse-work permission is OFF and the work implement is ON, satisfaction of the claimed reverse-direction and average-speed determinations would invoke Heal’s known forced implement-stopping response.
Motivation to Combine Heal and Wyatt
Therefore, given the teachings as a whole, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention, having Heal and Wyatt before them, to implement Heal’s reverse-responsive work-implement interlock and user-selectable reverse-work override in Wyatt’s independently driven, dual-lever work vehicle and to configure the resulting controller to determine unauthorized backward travel from the directions and speeds of the two driven wheels.
Heal and Wyatt address the same technical field and the same safety concern: controlling a mowing implement when a work vehicle is operated in reverse. Heal supplies a reverse-work interlock that stops the cutting unit when the vehicle enters reverse unless the operator has affirmatively activated a reverse-work permission control. Wyatt supplies a technically compatible, controller-based zero-turn vehicle having independently controlled left and right traction motors, corresponding left and right drive levers, and available propulsion direction and velocity information.
A PHOSITA would have recognized that Heal’s reverse interlock requires a reliable indication that the vehicle is actually traveling backward. In Wyatt’s dual-motor architecture, the individual direction and speed information for the two driven wheels provides the relevant information for making that determination. Using those controller-available signals would have predictably allowed Heal’s interlock to distinguish meaningful backward travel from neutral, wheel creep, or unequal wheel operation during steering.
It further would have been obvious to require both wheels to rotate backward and to require their average rearward speed to meet a predetermined value before forcibly stopping the work implement. This control rule would have:
reduced false cutoff events caused by sensor noise or minor wheel movement near neutral;
distinguished vehicle-level backward translation from pivoting or zero-turn operation;
provided a representative rearward vehicle speed despite unequal individual wheel speeds;
improved the accuracy and reliability of reverse-travel detection;
preserved Heal’s reverse-mowing safety function; and
produced predictable results using direction and speed values already available to Wyatt’s traction controllers.
The modification would not require bodily incorporation of Wyatt’s entire vehicle into Heal. Rather, a PHOSITA would apply Heal’s known reverse-work safety logic to Wyatt’s known controller-based propulsion architecture and use Wyatt’s existing left and right direction and speed signals to implement the reverse-state decision. Heal expressly recognizes that its control arrangement may be implemented in software, making Wyatt’s controller-based implementation technically compatible with Heal’s reverse-cutoff and override teachings.
Regarding Claim 4,
The combination of Heal and Wyatt establishes the control system of Claim 1, which is the basis for Claim 4.
Disclosure by Heal
Heal discloses:
The control system
See at least: “Control system 40 further includes a control module 52, a PTO status switch 54, an override switch 56, and a reverse switch 58.” (Heal, p. 5, col. 3, ll. 61–64.)
Rationale: Heal expressly discloses control system 40, including control module 52 and the PTO, override, and reverse switches through which the system controls the vehicle engine and cutting unit.
for a work vehicle
See at least: “Referring first to FIG. 1, a lawn mowing vehicle 10 is shown in perspective view.” (Heal, p. 4, col. 2, ll. 24–26.)
Rationale: Heal’s lawn-mowing vehicle 10 constitutes a work vehicle because the vehicle travels while carrying and operating a powered cutting implement.
according to claim 1,
See at least: “A powered implement is carried by the lawn mower 10 and may include a cutting unit 18 having a cutting deck 20 enclosing one or more rotatable cutting blades 22.” (Heal, p. 4, col. 2, ll. 27–31.)
Rationale: As established in the rejection of Claim 1, Heal, as modified by Wyatt, discloses or renders obvious the control system from which Claim 4 depends. Heal expressly provides the work-implement control and reverse-operation interlock, while Wyatt provides the claimed dual-motor, dual-lever travel-control architecture.
wherein
See at least: “At this point, two modes of vehicle 10 operation may then be entered. The first, a non-override mode.... Additionally a second mode, an override mode of operation....” (Heal, p. 6, col. 5, ll. 28–37.)
Rationale: Heal expressly discloses the following conditional operating relationships through its non-override and override operating modes.
in a case where the backward work permission switch is operated OFF
See at least: “The first, a non-override mode, permits the cutting unit 18 to remain engaged so long as the vehicle 10 remains in a forward gear (state 1) or in neutral (state 4).” (Heal, p. 6, col. 5, ll. 29–33.)
Rationale: Heal’s non-override mode is the operating condition in which the reverse-mowing override has not been activated. The non-override mode therefore functionally corresponds to the backward work permission switch being operated OFF.
and the work operation unit is operated ON,
See at least: “Cutting operations may commence after the user selectively actuates the PTO status switch 54 to engage the cutting unit 18.” (Heal, p. 6, col. 5, ll. 27–29.)
Rationale: Heal expressly discloses that the user actuates PTO status switch 54 to engage and operate cutting unit 18. Thus, the PTO switch—the claimed work operation unit—is in its ON operating condition before the vehicle enters the unauthorized reverse condition.
the control device forcibly stops the work implement
See at least: “If the vehicle 10 is under the non-override mode of operation and is then placed in reverse, the engine 28 and cutting unit 18 will be deactivated by operation of the control system 40....” (Heal, p. 6, col. 5, ll. 33–36.)
Rationale: Heal’s control system affirmatively deactivates the engine and cutting unit in response to the prohibited reverse condition. This controlled interruption of power prevents further operation of cutting unit 18 and therefore functionally constitutes forcibly stopping the work implement.
when the work vehicle travels backward,
See at least: “[T]he vehicle 10 in the non-override mode is prevented from cutting unit 18 engagement during reverse travel....” (Heal, p. 7, col. 7, ll. 7–10.)
Rationale: Heal expressly ties the cutting-unit deactivation to reverse travel when the reverse-mowing override has not been activated. Thus, the forced stop occurs when the work vehicle travels backward.
Claim Limitations Not Explicitly Disclosed by Heal
Heal does not explicitly disclose the following claim limitations:
and after forcibly stopping the work implement,
the control device drives the work implement
only when the work vehicle finishes backward traveling
and the work operation unit is shifted to an OFF operation
and then is shifted to an ON operation again.
Examiner Note: Heal does not expressly disclose the complete claimed recovery sequence under which, after the reverse-triggered forced stop, the cutting unit remains disabled until both:
the vehicle finishes backward traveling; and
the user deliberately cycles the work operation unit from ON to OFF and then back to ON.
In Heal’s PTO-clutch embodiment, reverse switch 84 interrupts the PTO-clutch current path while the vehicle is in reverse. When the vehicle leaves reverse, the reverse switch may reclose and restore that current path while the PTO switch remains ON. Heal therefore does not clearly require the claimed OFF-to-ON reset before the cutting unit can resume operation.
Disclosure by Wyatt
Wyatt discloses:
and after forcibly stopping the work implement,
See at least: “If traction controller(s) 80, 220 determines it should pass control to state 105 (attempted reverse mowing with ROS off) ... if a reverse cut-off function is selected in the software, then mowing is not allowed (‘105 Opt 2’ in FIG. 10) and a non-recoverable error is generated and control passes to state 102.” (Wyatt, [0059].); “Any alarm or emergency condition ... encountered by traction controller(s) 80, 220 or deck controller 82, 230 will result in passing control to state 102 and stopping of both the vehicle and the deck blades.” (Wyatt, [0058].)
Rationale: Wyatt expressly discloses a sequential control response. Attempted reverse mowing while reverse-operation permission is OFF causes the controller to invoke the reverse cutoff, transfer control to error state 102, and stop the deck blades. The recovery behavior associated with state 102 therefore occurs after the work implement has been forcibly stopped.
the control device drives the work implement
See at least: “If PTO switch 60 was on before entering error state 102, it will be necessary to cycle PTO switch 60 after recovery from the error in order to resume operation of mower deck motors 145, 234.” (Wyatt, [0058].)
Rationale: Wyatt expressly discloses that mower deck motors 145 and 234 resume operation under controller command after recovery from the reverse-cutoff error and completion of the required PTO-switch cycle. Powering the mower deck motors to resume cutting functionally constitutes the control device driving the work implement.
only when the work vehicle finishes backward traveling
See at least: “State 105 is the attempted reverse mowing with ROS off state.... [I]t does not allow any mowing (referenced in FIG. 10 as ‘105 Opt 2—Reverse Cut-Off’) and control is passed to state 102....” (Wyatt, [0061].); “Functionality of traction controller(s) 80, 220 is checked, the neutral state of the vehicle is verified, and the drive state is enabled. The inactive state of PTO switch 60 ... is also verified.” (Wyatt, [0043].)
Rationale: Wyatt expressly prevents mowing while the unauthorized reverse condition exists. State 105 identifies attempted reverse mowing with reverse-operation permission OFF as the prohibited condition and transfers control to the persistent error state. Wyatt further verifies the vehicle’s neutral state and the inactive condition of the PTO before normal drive operation is enabled.
To the extent Wyatt does not expressly recite in one passage that termination of backward travel must occur before implement operation resumes, that sequencing would have been obvious to a PHOSITA from Wyatt’s control logic and safety purpose. Reverse travel without reverse-operation permission is the condition that causes the implement cutoff. Permitting the deck motors to restart while that same prohibited reverse condition remained present would immediately recreate the fault and defeat Wyatt’s reverse-cutoff function. A PHOSITA therefore would have required the vehicle to leave the prohibited reverse state—such as by returning to neutral—before allowing recovery and renewed implement operation.
This is not merely a temporal coincidence. Finishing backward travel removes the specific unsafe operating condition that caused the forced stop and is therefore a functional prerequisite to restoring the implement-driving state.
and the work operation unit is shifted to an OFF operation
See at least: “If PTO switch 60 was on before entering error state 102, it will be necessary to cycle PTO switch 60 after recovery from the error in order to resume operation of mower deck motors 145, 234.” (Wyatt, [0058].); “When PTO switch 60 is switched off ... deck controller 82, 230 jumps to state 202 from state 205.” (Wyatt, [0071].)
Rationale: Wyatt expressly requires PTO switch 60 to be cycled before operation of the deck motors can resume. Because PTO switch 60 was ON when the reverse-cutoff error occurred, the first necessary part of that cycle is moving the switch from ON to OFF. Paragraph [0071] further confirms that switching the PTO control OFF transfers the deck controller from the PTO-disabled state to state 202. Wyatt therefore functionally requires the work operation unit to be shifted to an OFF operation after the forced stop.
and then is shifted to an ON operation again.
See at least: “In state 202, deck controller 82, 230 is enabled with key switch 58 on and PTO switch 60 off. When PTO switch 60 is switched on, deck controller 82, 230 jumps to state 203.” (Wyatt, [0068].); “In state 203, deck controller 82, 230 is enabled with key switch 58 on and PTO switch 60 on to power mower deck motors 145, 234.” (Wyatt, [0069].)
Rationale: Wyatt expressly discloses the second part of the required switch cycle. After PTO switch 60 has been placed in the OFF condition and the controller has entered state 202, the user moves PTO switch 60 back to ON. The controller then enters state 203 and powers deck motors 145 and 234. Thus, renewed driving of the work implement requires the claimed OFF operation followed by an ON operation again.
Motivation to Combine Heal and Wyatt
Therefore, given the teachings as a whole, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention, having Heal and Wyatt before them, to modify Heal’s reverse-responsive work-implement control system to incorporate Wyatt’s persistent reverse-cutoff recovery logic, such that, after the cutting unit is forcibly stopped because the vehicle travels backward without reverse-work permission, the control device permits the cutting unit to resume operation only after the vehicle finishes backward traveling and the operator deliberately cycles the work operation unit from ON to OFF and then back to ON.
Heal and Wyatt address the same type of work vehicle and the same reverse-operation safety problem. Both references monitor the state of the work-implement control, the vehicle’s direction of travel, and a user-operated reverse-work permission control. Their teachings are therefore technically compatible and complementary.
Heal provides a known reverse-responsive safety interlock that deactivates the engine or cutting unit when the mower enters reverse without an active override. Wyatt improves the recovery behavior following such an unauthorized reverse-mowing event by placing the controller in a persistent error state and requiring deliberate operator action before the cutting implement can resume operation.
Applying Wyatt’s persistent cutoff and PTO-reset logic to Heal would have been a predictable use of known safety-interlock logic according to its established function. A PHOSITA would have been motivated to make the modification because Heal’s PTO-clutch embodiment may otherwise allow the PTO current path to be restored when the vehicle leaves reverse and the reverse switch recloses while the PTO switch remains ON. Wyatt’s recovery logic would prevent that automatic restart by requiring the operator to move the PTO switch OFF and then affirmatively turn it ON again.
The modification would have predictably:
prevented automatic cutting-unit reengagement immediately after reverse travel;
ensured that the unsafe reverse condition had ended before cutting resumed;
required a deliberate and observable operator decision to restart the implement;
prevented unexpected blade movement when the vehicle returns to neutral or forward travel;
improved the reliability and determinism of the reverse-work interlock; and
improved operator and bystander safety.
Heal expressly recognizes that its control system may be implemented in software. A PHOSITA therefore could have incorporated Wyatt’s state-machine recovery logic into Heal’s control module while retaining Heal’s PTO switch, reverse switch, override switch, cutting unit, and reverse-responsive cutoff arrangement. The modification would not require bodily incorporation of Wyatt’s entire electric vehicle into Heal.
Regarding Claim 5,
The combination of Heal and Wyatt establishes the control system of Claim 4, which is the basis for Claim 5.
Disclosure by Heal
Heal discloses:
The control system
See at least: “Control system 40 further includes a control module 52, a PTO status switch 54, an override switch 56, and a reverse switch 58.” (Heal, p. 5, col. 3, ll. 61–64.)
Rationale: Heal expressly discloses control system 40, including control module 52 and the PTO, override, and reverse switches through which the vehicle engine and cutting unit are controlled.
for a work vehicle
See at least: “Referring first to FIG. 1, a lawn mowing vehicle 10 is shown in perspective view.” (Heal, p. 4, col. 2, ll. 24–26.)
Rationale: Heal’s lawn-mowing vehicle 10 is a work vehicle because it travels while carrying and operating a powered cutting implement.
according to claim 4,
See at least: “If the vehicle 10 is under the non-override mode of operation and is then placed in reverse, the engine 28 and cutting unit 18 will be deactivated by operation of the control system 40....” (Heal, p. 6, col. 5, ll. 33–36.)
Rationale: As established in the rejection of Claim 4, Heal, as modified by Wyatt, discloses or renders obvious the control system from which Claim 5 depends, including the reverse-triggered implement cutoff and the required recovery sequence.
the control system comprising:
See at least: “Control system 40 further includes a control module 52, a PTO status switch 54, an override switch 56, and a reverse switch 58.” (Heal, p. 5, col. 3, ll. 61–64.)
Rationale: Heal expressly identifies multiple components constituting control system 40. The additional traveling motors and operation levers are supplied by Wyatt as discussed below.
wherein
See at least: “At this point, two modes of vehicle 10 operation may then be entered. The first, a non-override mode.... Additionally a second mode, an override mode of operation....” (Heal, p. 6, col. 5, ll. 28–37.)
Rationale: Heal expressly discloses the following conditional control relationships through its non-override and override operating modes.
in a case where the backward work permission switch is operated OFF
See at least: “The first, a non-override mode, permits the cutting unit 18 to remain engaged so long as the vehicle 10 remains in a forward gear (state 1) or in neutral (state 4).” (Heal, p. 6, col. 5, ll. 29–33.)
Rationale: Heal’s non-override mode is the condition in which the reverse-mowing override has not been activated. It therefore functionally corresponds to the backward work permission switch being operated OFF.
and the work operation unit is operated ON,
See at least: “Cutting operations may commence after the user selectively actuates the PTO status switch 54 to engage the cutting unit 18.” (Heal, p. 6, col. 5, ll. 27–29.)
Rationale: Heal expressly discloses that PTO status switch 54 is actuated to engage cutting unit 18. Thus, the work operation unit is in its ON operating condition when the subsequent unauthorized reverse condition occurs.
the control device forcibly stops the work implement
See at least: “If the vehicle 10 is under the non-override mode of operation and is then placed in reverse, the engine 28 and cutting unit 18 will be deactivated by operation of the control system 40....” (Heal, p. 6, col. 5, ll. 33–36.)
Rationale: Heal’s control system affirmatively deactivates the engine and cutting unit upon detecting unauthorized reverse travel. The resulting controlled interruption of implement-driving power functionally constitutes the control device forcibly stopping the work implement.
Claim Limitations Not Explicitly Disclosed by Heal
Heal does not explicitly disclose the following claim limitations:
two traveling motors left and right
coupled to two wheels at left and right
and driven independently from each other; and
two operation levers
as the traveling operation units
that are arranged separately at left and right of a driver's seat
and each of which instructs a rotation direction and rotation speed of one of the wheels located at a corresponding side
by moving of the corresponding operation lever,
at least one of when it is determined that the two wheels at left and right rotate in a backward direction
and when it is determined that average speed of the two wheels at left and right is equal to or higher than a predetermined value in terms of speed in the backward direction.
Examiner Note: Heal discloses a reverse-responsive work-implement interlock, but it does not specifically disclose the claimed independently controlled left and right motor-and-wheel architecture, corresponding left and right operation levers, or the two recited wheel-based criteria for determining when to invoke the forced implement stop.
Disclosure by Wyatt
Wyatt discloses:
two traveling motors left and right
See at least: “Power supply 238 of vehicle 300 drives an electric motor 341 located on each EPRM 310a and 310b....” (Wyatt, [0036].)
Rationale: Wyatt expressly discloses respective electric traction motors associated with the left and right propulsion assemblies. Because these motors provide the motive power that travels the vehicle, they functionally constitute the claimed left and right traveling motors.
coupled to two wheels at left and right
See at least: “[Electric motors 341] in turn drive planetary reduction transmission/gearing 314a and 314b, coupled to axle shafts 313a and 313b, thereby separately driving rear wheels 212a and 212b.” (Wyatt, [0036].)
Rationale: Wyatt expressly discloses a mechanical power path from each electric motor through corresponding reduction gearing and an axle shaft to a respective rear wheel. Each traveling motor is therefore coupled to a corresponding left or right wheel.
and driven independently from each other; and
See at least: “Master traction controller 220a controls transaxle 210a and communicates with slave traction controller 220b.... Slave controller 220b controls transaxle 210b....” (Wyatt, [0037].)
Rationale: Wyatt assigns the respective left and right transaxles to separate traction-control channels. The respective motors and wheels can consequently be operated at different speeds or in different directions to provide vehicle propulsion and zero-turn steering. The two traveling motors are therefore functionally driven independently from each other.
two operation levers
See at least: “[S]teering interfaces take the form of a right drive lever 236a and a left drive lever 236b....” (Wyatt, [0037].)
Rationale: Wyatt expressly identifies two distinct operator-manipulated drive levers: right drive lever 236a and left drive lever 236b.
as the traveling operation units
See at least: “If accelerator pedal 52 or drive levers 236 have been moved out of the neutral position, the electric motors 41, 241 are started and operated at the respective speed and direction indicated.” (Wyatt, [0044].)
Rationale: The drive levers provide the operator inputs that start and control the respective propulsion motors. They therefore function as the interfaces through which the operator commands vehicle travel and constitute the claimed traveling operation units.
that are arranged separately at left and right of a driver's seat
See at least: “[S]teering interfaces take the form of a right drive lever 236a and a left drive lever 236b.... Associated with these operator-manipulated drive levers are sensors and switches....” (Wyatt, [0037].)
Rationale: Wyatt expressly distinguishes the operator-manipulated controls as a right drive lever and a left drive lever in a seated zero-turn mowing vehicle. A PHOSITA would understand the disclosed conventional dual-lever configuration as placing the two levers separately on the corresponding right and left sides of the operator’s seat so that the seated operator can manipulate each lever with the corresponding hand. At minimum, that placement would have been the ordinary and predictable arrangement for Wyatt’s expressly identified right and left drive levers.
and each of which instructs a rotation direction and rotation speed of one of the wheels located at a corresponding side
See at least: “A right drive lever position sensor 291a is associated with the right drive lever ... and is in communication with the master traction controller 290a. Similarly, a left drive lever position sensor 291b is associated with the left drive lever ... and is in communication with the slave traction controller 290b.” (Wyatt, [0039].)
Rationale: Wyatt functionally associates each drive lever and its position sensor with the traction controller for the corresponding side. Each controller, in turn, controls its respective transaxle and driven wheel. Consequently, each lever supplies the command that determines the direction and speed of the wheel on its corresponding side.
by moving of the corresponding operation lever,
See at least: “Sensors/switches 237a and 237b may be actuated directly by drive levers 236....” (Wyatt, [0037].)
Rationale: Wyatt expressly discloses that movement of each drive lever directly actuates its associated position sensor or switch. The detected lever position is communicated to the corresponding traction controller and determines the commanded direction and speed of the respective propulsion motor and wheel. Thus, the wheel-control instruction results from moving the corresponding operation lever.
at least one of when it is determined that the two wheels at left and right rotate in a backward direction
See at least: “A reverse state of the vehicle can be defined several ways, depending on control architecture and vehicle type.” (Wyatt, [0073].); “In an embodiment employing two traction controllers and two electric transaxles, the reverse mode can be defined as a vehicle travel condition in which either one or both of the electric transaxles are moving in reverse.” (Wyatt, [0073].)
Rationale: Wyatt expressly discloses determining a reverse operating state from the directions of the two independently controlled electric transaxles. Wyatt expressly encompasses the condition in which both transaxles—and therefore both corresponding driven wheels—are rotating in reverse. Wyatt further discloses a reverse-cutoff option under which attempted reverse mowing without reverse-operation permission causes mowing to be prohibited and the deck blades to be stopped. Accordingly, determining that both driven wheels are rotating backward provides one disclosed criterion for invoking the reverse-responsive implement cutoff. The phrase “at least one of” makes the recited criteria alternatives: the forced stop may be invoked based on the determination that both wheels rotate backward, based on the average-speed determination, or based on both determinations. Wyatt’s express two-transaxle reverse-state determination satisfies the first alternative.
and when it is determined that average speed of the two wheels at left and right is equal to or higher than a predetermined value in terms of speed in the backward direction.
See at least: “A reverse state of the vehicle can be defined several ways, depending on control architecture and vehicle type.” (Wyatt, [0073].); “In another embodiment, the mode of the vehicle may be defined by the direction of the axle, wheel, tire, etc., having the greater velocity.” (Wyatt, [0073].)
Rationale: Wyatt does not expressly disclose calculating the arithmetic average of the left and right wheel speeds and comparing that average with a predetermined rearward-speed value. Wyatt nevertheless expressly discloses determining the vehicle’s operating mode using wheel, axle, or tire direction and velocity and recognizes that different reverse-state definitions may be selected based on the particular vehicle and control architecture. Wyatt’s two traction controllers necessarily possess or derive speed information for the corresponding propulsion assemblies because the controllers operate the respective motors at the speed and direction commanded by the drive levers. Thus, the left and right speed values needed to calculate an average are already available within Wyatt’s control architecture. It would have been obvious to a PHOSITA to use the average of the two wheel speeds as a representative vehicle speed. In an independently driven, differential-drive vehicle, the two wheels can rotate at different speeds during steering. Averaging the respective wheel speeds is a conventional and predictable technique for representing the vehicle’s translational speed without allowing the faster individual wheel alone to control the vehicle-level speed determination. It further would have been obvious to compare that representative rearward speed with a predetermined value before invoking the reverse-responsive implement stop. A predetermined threshold would distinguish actual backward travel from zero-speed sensor variation, control deadband, or minor wheel creep near neutral. This would improve the accuracy and reliability of Wyatt’s reverse-state determination while avoiding unnecessary interruptions of the work implement. Accordingly, when Heal’s reverse-work permission is OFF and the PTO is ON, using Wyatt’s available left and right wheel-speed information to determine whether their average is equal to or greater than a stored rearward-speed threshold would have been a predictable application of known vehicle-control techniques. Satisfaction of that alternative criterion would cause Heal’s control device to invoke the known forced implement-stopping response.
Motivation to Combine Heal and Wyatt
Therefore, given the teachings as a whole, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention, having Heal and Wyatt before them, to implement Heal’s reverse-responsive work-implement interlock and user-selectable reverse-work permission control in Wyatt’s independently driven, dual-lever work vehicle and to determine when to invoke the implement cutoff using at least one of: (1) a determination that both corresponding driven wheels are rotating in the backward direction; and (2) a determination that the average speed of the two driven wheels has reached a predetermined value in the backward direction.
Heal and Wyatt address the same type of work vehicle and the same reverse-mowing safety concern. Heal provides a known safety interlock that stops a cutting implement when the vehicle travels backward without an active reverse-work override. Wyatt provides a technically compatible work vehicle having independently driven left and right propulsion motors, corresponding left and right operator levers, controller-available direction and speed information, and a programmable reverse-cutoff function.
A PHOSITA would have recognized that applying Heal’s interlock to Wyatt’s dual-motor architecture requires a reliable definition of when backward travel exists. Wyatt expressly recognizes this design issue and states that the vehicle’s reverse state may be defined in different ways depending on the vehicle and control architecture. Wyatt further identifies the direction and velocity of the respective propulsion components as suitable inputs for making that determination.
Using either the direction of both driven wheels or a thresholded average of their rearward speeds would have been a predictable use of Wyatt’s existing propulsion information. The two criteria are complementary:
the two-wheel direction criterion determines whether both sides are commanding backward travel; and
the average-speed criterion provides a representative measure of whether meaningful vehicle-level backward motion has begun.
The alternative criteria would allow the controller to accommodate different operating states and control objectives without changing the basic operation of either reference. The modification would predictably:
distinguish backward vehicle travel from neutral or insignificant wheel creep;
account for unequal left and right wheel speeds during steering;
reduce false implement cutoffs caused by sensor noise or control deadband;
improve the accuracy and reliability of reverse-travel detection;
preserve Heal’s reverse-operation safety function; and
improve operator and bystander safety.
Heal also expressly recognizes that its control system may be implemented in software. A PHOSITA therefore could have implemented the claimed alternative decision criteria in the traction or implement controller using Wyatt’s existing direction and speed signals, while retaining Heal’s PTO control, reverse-work override, and forced implement-stopping logic. No bodily incorporation of Wyatt’s entire vehicle into Heal would have been required.
Response to Arguments
Applicant’s remarks filed on 02/27/2026 in response to the prior non-final Office Action have been fully considered. The previous rejections have been withdrawn and replaced with new rejections based on Heal in view of Wyatt. Because the present rejections do not rely on Olson, Haun, or Peter, Applicant’s arguments directed to those references and to the former anticipation rejection based on Heal alone are moot.
The present Office Action is made non-final because it relies on materially different prior-art findings and reasoning. Applicant’s arguments are nevertheless addressed below for completeness.
Claim 1
Applicant argues that Heal does not anticipate Claim 1 because Heal does not disclose forcibly stopping the work implement when the vehicle is shifted from a backward-traveling state to a stopped state.
Specifically, Applicant argues that:
Heal’s disclosure of the vehicle “being placed in reverse” concerns a transition into reverse, not the claimed transition from backward travel to a stopped state;
Heal’s neutral state does not necessarily establish that the vehicle has stopped;
Heal does not disclose an affirmative control action triggered by the transition from backward travel to a stopped state;
continued implement stopping after reverse travel is not necessarily or inherently present in Heal;
Heal does not disclose a latch, rearming requirement, or persistent cutoff that prevents automatic implement restart after reverse travel; and
Heal does not recognize the safety concern associated with unintended implement restart when the vehicle stops after traveling backward.
These arguments are persuasive as to the former anticipation rejection based on Heal alone. The present rejection therefore does not rely on the previous findings that Heal’s disclosure of “being placed in reverse” establishes a transition from backward travel to a stopped state, that Heal’s neutral condition necessarily constitutes the claimed stopped state, or that continued implement stopping after reverse travel is inherent in Heal.
The present rejection instead applies Heal in view of Wyatt.
Heal discloses the reverse-responsive work-implement interlock, including a user-operated PTO switch, a user-operated reverse-work override, forced deactivation of the engine or cutting unit when the vehicle enters reverse without the override, and continued cutting-unit operation during reverse when the override is activated.
Wyatt supplies the persistent cutoff behavior not clearly disclosed by Heal. Wyatt discloses that attempted reverse mowing with reverse-operation permission OFF causes mowing to be prohibited, generates a nonrecoverable error, and transfers control to state 102. State 102 stops the vehicle and deck blades. If the PTO switch was ON before entry into state 102, deck-motor operation cannot resume until recovery from the error and deliberate cycling of the PTO switch. See Wyatt [0058]–[0061].
Thus, the present rejection does not rely on inherency. It relies on Wyatt’s express persistent error-state logic and the reasoned application of that logic to Heal. Applying Wyatt’s logic to Heal would maintain the implement stop as the vehicle leaves reverse and enters the resulting stopped state, rather than allowing the cutting unit to restart merely because Heal’s reverse switch recloses.
Heal and Wyatt address the same reverse-mowing safety problem. A PHOSITA would have been motivated to incorporate Wyatt’s persistent cutoff logic into Heal to prevent unexpected blade reengagement, provide deterministic recovery from an unauthorized reverse-mowing event, and allow the operator to verify surrounding safety conditions before restarting the cutting unit.
Applicant’s reliance on present Figure 6 and the asserted benefits of preventing abrupt implement restart is acknowledged. Those benefits are the predictable safety results of applying Wyatt’s persistent cutoff and deliberate-reset logic to Heal and therefore do not establish nonobviousness.
Accordingly, Applicant’s arguments do not overcome the new rejection of Claim 1 over Heal in view of Wyatt.
Claims 2 and 4
Applicant argues that Claims 2 and 4 are patentable because Heal does not disclose the limitations of Claim 1 and Olson does not cure Heal’s deficiencies.
The argument directed to Olson is moot because Olson is not relied upon in the present rejection. The former rejection over Heal and Olson has been withdrawn.
The present rejection relies on Wyatt’s persistent reverse-cutoff and reset logic. Wyatt expressly discloses:
“If PTO switch 60 was on before entering error state 102, it will be necessary to cycle PTO switch 60 after recovery from the error in order to resume operation of mower deck motors 145, 234.” Wyatt [0058].
Wyatt further discloses that switching PTO switch 60 OFF transfers the deck controller to state 202 and that subsequently switching the PTO switch ON transfers the controller to state 203, in which the mower deck motors are powered. See Wyatt [0068]–[0071].
Wyatt therefore expressly supplies the required OFF-to-ON reset. To the extent Wyatt does not expressly describe the entire recovery sequence in a single passage, requiring the vehicle to finish backward travel before permitting implement restart would have been obvious from Wyatt’s control logic. Unauthorized reverse travel is the condition that invokes the cutoff. Restarting the implement while that prohibited reverse condition remains present would immediately recreate the fault and defeat the purpose of the reverse cutoff. Ending backward travel is therefore a predictable functional prerequisite to recovery.
Applicant’s remarks also refer to “dependent claims 9.” No Claim 9 is pending. Based on the heading and substance of the remarks, the argument has been treated as applying to Claims 2 and 4.
Accordingly, Applicant’s arguments directed to Heal and Olson do not overcome the new rejection of Claims 2 and 4 over Heal in view of Wyatt.
Claim 3
Applicant argues that Heal, Haun, and Peter do not disclose the amended final limitation of Claim 3. Applicant contends that:
the former “at least one of” language was removed;
Haun uses average wheel speed only to filter near-zero speeds, sensor noise, or transient wheel motion;
Haun does not use an average-speed threshold to identify hazardous backward travel;
Haun does not use that determination to forcibly stop a work implement;
combining Heal and Haun would, at most, use the average-speed calculation for vehicle stabilization;
Peter does not cure those deficiencies; and
the claimed control detects a backward turn in which the two wheels may rotate differently.
The amendment removing “at least one of” has been entered and considered. Pending Claim 3 is examined using its current language, including “both when.” That language requires the control device to provide both recited stopping capabilities: stopping when both wheels are determined to rotate backward and stopping when the average rearward-speed criterion is satisfied. The rejection does not treat the pending limitation as satisfied by the first condition alone.
Applicant’s arguments concerning Haun and Peter are moot because neither reference is relied upon in the present rejection. The present rejection also does not rely on Haun’s alleged filtering of sensor noise or transient wheel motion.
Wyatt discloses the independently controlled, dual-motor and dual-lever propulsion architecture recited in Claim 3. Wyatt further discloses that a reverse state may be defined using the directions and velocities of the independently controlled electric transaxles, including:
“a vehicle travel condition in which either one or both of the electric transaxles are moving in reverse,”
and, in another embodiment, by the direction of the axle, wheel, or tire having the greater velocity. Wyatt [0073].
Wyatt therefore expressly recognizes that reverse travel in an independently driven vehicle may be determined using direction and velocity information from the left and right propulsion components. Wyatt’s determination concerns the vehicle’s operating mode, not merely filtering an unrelated sensor signal.
Wyatt does not expressly disclose calculating the arithmetic average of the left and right wheel speeds or comparing that average with a predetermined rearward-speed value. The present rejection does not characterize those features as expressly disclosed. Rather, the rejection relies on the obvious implementation of Wyatt’s wheel-speed-based reverse determination in Heal’s reverse-responsive safety system.
Wyatt’s traction controllers already possess or derive the respective speed and direction information necessary to operate the left and right traction motors at the commands provided by the corresponding drive levers. In a differential-drive vehicle, the two wheels may rotate at different speeds or in opposite directions during turning. Using the average of the two wheel speeds as the representative vehicle speed would have been a predictable selection among known methods of deriving vehicle-level translational speed from the available individual wheel-speed values.
It further would have been obvious to compare that representative rearward speed with a predetermined value before declaring meaningful backward travel. A threshold would distinguish actual rearward vehicle movement from insignificant wheel creep, control deadband, or sensor variation near neutral. The resulting control would account for a backward turn in which the individual wheels do not rotate identically but the vehicle moves backward as a whole.
Heal supplies the known safety response to that reverse-travel determination: forcibly stopping the work implement when reverse-work permission is OFF and the work operation unit is ON. Using Wyatt’s available wheel-direction and wheel-speed information to control Heal’s reverse-responsive interlock would predictably improve the accuracy and reliability of reverse-travel detection and prevent continued implement operation during a hazardous backward maneuver.
Applicant’s asserted advantage of detecting a backward turn despite unequal wheel behavior is therefore acknowledged. That advantage is the predictable result of determining vehicle-level rearward movement from the respective wheel-speed information and does not establish that the claimed control would have been beyond the ordinary skill in the art.
Accordingly, Applicant’s arguments directed to the former Heal-Haun-Peter rejection do not overcome the new rejection of Claim 3 over Heal in view of Wyatt.
Claim 5
Applicant argues that Claim 5 is patentable because Claim 1 allegedly distinguishes over Heal, Olson, Haun, and Peter and because Claim 5 depends from Claim 4.
These arguments are moot as directed to Olson, Haun, and Peter because those references are not relied upon in the present rejection.
The present rejection applies Heal in view of Wyatt to the limitations inherited from Claims 1 and 4 and to the additional limitations of Claim 5. As explained above:
Heal discloses the work-implement control, reverse-work permission switch, and forced implement stopping during unauthorized reverse travel;
Wyatt supplies the persistent cutoff and deliberate PTO OFF-to-ON recovery sequence;
Wyatt discloses independently controlled left and right traveling motors and corresponding driven wheels;
Wyatt discloses right and left drive levers associated with the corresponding traction-control channels; and
Wyatt discloses determining reverse operation from the directions and velocities of the independently controlled propulsion components.
Claim 5 recites that the control device forcibly stops the work implement “at least one of” when both wheels rotate backward and when the average-speed criterion is satisfied. Under the broadest reasonable interpretation consistent with the specification, this language establishes alternative stopping conditions. The limitation is satisfied when either condition is present.
Wyatt expressly discloses defining reverse operation when both electric transaxles move in reverse. See Wyatt [0073]. Because the transaxles drive the corresponding wheels, Wyatt satisfies the first alternative of Claim 5. Establishing the arithmetic-average alternative is therefore not necessary to meet this additional limitation of Claim 5.
Applicant’s dependency argument does not independently establish patentability because the limitations inherited from Claims 1 and 4 are addressed by the Heal-Wyatt combination, and Wyatt additionally addresses the structural and wheel-based limitations added by Claim 5.
Accordingly, Applicant’s arguments do not overcome the new rejection of Claim 5 over Heal in view of Wyatt.
Examiner Response Conclusion
Applicant’s arguments were directed to the former rejections based on Heal alone and Heal in combination with Olson, Haun, and Peter. Those rejections have been withdrawn.
The present second non-final Office Action relies on the materially different combination of Heal and Wyatt and on new factual findings and reasons to combine. Applicant’s arguments therefore do not overcome the rejections set forth in this Office Action.
Conclusion
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/OLUWABUSAYO ADEBANJO AWORUNSE/Examiner, Art Unit 3662
/JELANI A SMITH/Supervisory Patent Examiner, Art Unit 3662
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