DETAILED ACTION
Response to Amendment
The Amendment filed February 5, 2026 has been entered. Claims 1 – 3, 5, 7, 21, 30 – 38 and 40 – 44 are pending in the application with claims 4, 6, 8 – 20, 22 – 29 and 39 being cancelled and claims 43 and 44 being newly added. The amendment to the claims has overcome the 35 USC 112 rejections set forth in the last Non-Final Action, dated 11/06/2025.
Examiners Note
Claim 35 is not being examined on the merits because the limitations of independent claim 1 (upon which the claims depend) are recited in the alternative and the phase position alternative has been considered in the prior art rejection of independent claim 1 below.
Claim 36 is no longer considered to be withdrawn in view of the amendment made to independent claim 1.
Claim Rejections - 35 USC § 103
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, 2, 5, 7, 21 and 36 – 38 are rejected under 35 U.S.C. 103 as being unpatentable over Zhong et al. (US 2022/0333471 – herein after Zhong) in view of Schafer et al. (US 2009/0276145 – herein after Schafer).
In reference to claim 1, Zhong teaches a method of controlling a dual-pump single-power source system (see fig. 3: fracturing apparatus 100 comprising of a single power source 120 driving two pumps 110 is shown) [note the following: various embodiments of fracturing apparatus 100 are shown; discussion is further made on “engagement/disengagement” of clutch based on speed variable in view of fig. 2 by Zhong; furthermore as per disclosure in ¶63: “FIG. 5 is a schematic diagram of a fracturing system according to an embodiment of the present disclosure. The fracturing system 300 includes the fracturing apparatus 100 provided by any one of the above examples”; thus, figs. 2, 3 and 5 are relied upon in the rejection below, wherein fig. 3 teaches the claimed dual-pump single power source system, fig. 2 teaches the “engagement/disengagement” of the clutch based on speed sensors 191, 192 in fig. 3 and fig. 5 teaches the presence of the controller to control the system shown in fig. 3], comprising:
obtaining, by a controller (see fig. 5: 230) and via a first sensor (speed sensor 192 in fig. 3; see ¶55, ¶57) coupled to at least one of a power source (120) or a clutch (left 130, in view of fig. 3) coupled to the power source, a first measurement value (measurement value corresponding to the sensor 192) indicating a rotational speed of an input to the clutch (speed value from speed sensor 192, see ¶55; this speed value corresponds to clutch’s input speed);
obtaining, by the controller and via a second sensor (speed sensor 191 in fig. 3; see ¶55, ¶57) coupled to the clutch, a second measurement value (value from another speed sensor 191) indicating a rotational speed of an output of the clutch (speed value from speed sensor 192, see ¶55; this speed value corresponds to clutch’s output speed);
detecting, by the controller, that the clutch (130) is experiencing slippage based on comparing the first measurement value and the second measurement value (see ¶55: “upon the actual rotation speed detected by the first rotation speed sensor 191 not matching the actual rotation speed detected by the second sensor 192, for example, the transmission ratio being not conformed, it can be judged that the clutch is abnormal. In this case, the clutch can be controlled to disengage, so that further deterioration of the fault can be avoided, and pertinent overhaul and maintenance can be carried out”); and
performing, by the controller and based on determining that the clutch is experiencing slippage, an action to cause the clutch to disengage a mechanical connection (131, 132) between a first pump (110 on left in view of fig. 3) and the power source while the power source is running and is mechanically connected to a second pump (110 on right in view of fig. 3) [see ¶57: “upon the rotation speed of any one of the two plunger pumps detected by the two first rotation speed sensors 191 being not match the rotation speed of the prime mover detected by the second rotation speed sensor 192, the corresponding clutch can be controlled to disengage, thereby ensuring the normal operation of the other plunger pump”].
Zhong remains silent on the method, wherein the first measurement value indicating “a crank angle or a phase position” of the input shaft of the clutch; and wherein the second measurement value indicating “a crank angle or a phase position” of the output shaft of the clutch.
However, Schafer teaches (see abstract, ¶9, ¶11, ¶43, ¶44) a first active sensor that provides a first measurement value indicating a phase position (angular position) of a first shaft, and a second active sensor that provides a second measurement value indicating a phase position (angular position) of a second shaft.
Schafer emphasizes the need for “active sensors” with high resolution and the ability to recognize reverse rotation and slow rotation (tending toward zero RPM) {see ¶16, ¶20, ¶68-¶71}. These are all capabilities inherent to phase/angle sensors and are crucial for rapid, precise control required in high-power applications (like the fracturing system in Zhong) and for early, sensitive slippage detection. Clutch slippage is fundamentally a change in the relative phase position between the input and output shafts. Thus, it would have been obvious to the person of ordinary skill in the art before the effective filing date of the invention to substitute each of the first and second sensors in the method of Zhong for the active sensor as taught by Schafer in order to obtain the predictable result of detecting clutch slippage. KSR Int’l v. Teleflex Inc., 127 S. Ct. 1727, 1740-41, 82 USPQ2d 1385, 1396 (2007).
In reference to claim 2, Zhong, as modified, teaches the method (see Zhong), wherein the clutch (130) is a shaft-mounted hydraulically actuated clutch (see ¶40, ¶42 and ¶43; clutch 130 is a hydraulically actuated clutch and is mounted on shafts 125, 1125), and wherein the clutch is coupled to an output shaft (125, see fig. 3) of the power source (120) and an input shaft (1125, see fig. 3) of the first pump.
In reference to claim 5, Zhong, as modified, teaches the method, wherein detecting that the clutch is experiencing slippage comprises:
determining a difference between the first measurement value and the second measurement value; and
determining that the clutch is experiencing slippage based on the difference satisfying a threshold
[ Zhong teaches (¶55) a controller that obtains a first measurement value from the input side of a clutch, a second measurement value from the output side of the clutch, calculates a mathematical difference or ratio relationship between these two values, and determines that the clutch is experiencing slippage when that variance satisfies a predetermined threshold;
in the modified method, the first measurement value represents the phase position of the clutch input shaft and the second measurement represents the phase position of the clutch output shaft; the modified method achieves the exact same functional result using the same logical steps; the only difference is that the specific physical variable being and compared is substituted from “speed” (as taught by Zhong) to “phase position” (as taught by Schafer].
In reference to claim 7, Zhong, as modified, teaches the method (see Zhong), wherein performing the action to cause the clutch to disengage comprises: providing a signal to cause a hydraulic circuit (clutch hydraulic system 140) to provide or remove hydraulic fluid to the clutch to cause the clutch to be disengaged (see ¶45: “the fracturing apparatus can control the clutch hydraulic system through the control system to make the clutch quickly disengage”).
In reference to claim 21, Zhong, as modified, teaches the method, further comprising: obtaining an identifier associated with the clutch; and identifying, based on the identifier, the clutch [this claimed feature is an inherent feature; sensor(s) is/are in communication with a control system (in view of Zhong’s disclosure in ¶24) that controls engagement/disengagement of clutch; sensor(s) have a unique identifier (such as in the form of a hardware address or id, port or channel assignment) that allows the control system to determine which data came from which sensor; the identifier can take various forms depending on the communication protocol and system architecture; thus based on this identifier (i.e. identifier communicated along with speed data from the sensor(s)), clutch that is to be engaged/disengaged is identified by the control system].
In reference to claim 36, Zhong, as modified, teaches the method, wherein (see proposed modification discussed above in claim 1) the first measurement value indicates the phase position (as per Schafer) of the input shaft (of Zhong), and wherein the second measurement value indicates the phase position (as per Schafer) of the output shaft (of Zhong).
In reference to claim 37, Zhong, as modified, teaches the method, wherein (see Zhong) the first sensor (192, see fig. 3) is coupled to the power source (120).
In reference to claim 38, Zhong, as modified, teaches the method, wherein (see Zhong) the first sensor (192, see fig. 3) is coupled to the clutch (130).
Claim 3 is rejected under 35 U.S.C. 103 as being unpatentable over Zhong in view of Schafer and Sayman et al. (US 2005/0073398 - herein after Sayman).
Zhong teaches the system, further comprising (see fig. 5): a display module (254) in a control panel (250) [see ¶66: "the remote control unit 250 can receive the data of the control system 230 and display it on the display module 254"]; and an input module (253) for an operator (user) [see ¶66: "The user can also send control instructions to the control system 230 through the input module 253 of the remote control unit 250"].
Zhong remains silent on the method, comprising: "providing a control panel indication to cause a notification that the clutch is experiencing slippage to be displayed" and "obtaining an operator input to disengage the clutch based on causing the notification to be displayed, wherein performing the action to cause the clutch to disengage is based on obtaining the operator input".
However, Sayman teaches a method wherein, clutch slippage notification is provided on a display so that operator can take corrective action (see ¶17).
Thus, it would have been obvious to the person of ordinary skill in the art to further modify the method of Zhong for having a user control the operation of the clutch based on clutch slippage notification on the display as taught by Sayman so that the user/operator can be notified in an event of excessive clutch slippage, as recognized by Sayman (see ¶17).
Claims 40 – 42 and 44 are rejected under 35 U.S.C. 103 as being unpatentable over Zhong et al. (US 2022/0333471 – herein after Zhong) in view of Coli et al. (US 9,140,110 – herein after Coli) and further in view of Blakely et al. (US 2014/0268432 – herein after Blakely).
In reference to claim 40, Zhong teaches a method of controlling a dual-pump single-power source system (see fig. 3: fracturing apparatus 100 comprising of a single power source 120 driving two pumps 110 is shown) [note the following: various embodiments of fracturing apparatus 100 are shown; discussion is further made on “engagement/disengagement” of clutch based on speed variable in view of fig. 2 by Zhong; furthermore as per disclosure in ¶63: “FIG. 5 is a schematic diagram of a fracturing system according to an embodiment of the present disclosure. The fracturing system 300 includes the fracturing apparatus 100 provided by any one of the above examples”; thus, figs. 2, 3 and 5 are relied upon in the rejection below, wherein fig. 3 teaches the claimed dual-pump single power source system, fig. 2 teaches the “engagement/disengagement” of the clutch based on speed sensors 191, 192 in fig. 3 and fig. 5 teaches the presence of the controller to control the system shown in fig. 3], comprising:
obtaining, by a controller (see fig. 5: 230) and via a first sensor (speed sensor 192 in fig. 3; see ¶55, ¶57) coupled to a power source (120), a first measurement value (measurement value corresponding to the sensor 192) indicating an output speed of the power source (speed value from speed sensor 192, see ¶55; this speed value corresponds to output speed of the power source 120);
obtaining, by the controller and via a second sensor (speed sensor 191 in fig. 3; see ¶55, ¶57) coupled to a clutch (left 130, in view of fig. 3), a second measurement value (value from another speed sensor 191) indicating an input speed of the clutch or an output speed of the clutch (see ¶55: “upon the actual rotation speed detected by the first rotation speed sensor 191 not matching the actual rotation speed detected by the second sensor 192, for example, the transmission ratio being not conformed, it can be judged that the clutch is abnormal. In this case, the clutch can be controlled to disengage, so that further deterioration of the fault can be avoided, and pertinent overhaul and maintenance can be carried out”);
detecting, by the controller, that the clutch (130) is experiencing slippage based on comparing the output speed of the power source and the second measurement value (see ¶55: “upon the actual rotation speed detected by the first rotation speed sensor 191 not matching the actual rotation speed detected by the second sensor 192, for example, the transmission ratio being not conformed, it can be judged that the clutch is abnormal. In this case, the clutch can be controlled to disengage, so that further deterioration of the fault can be avoided, and pertinent overhaul and maintenance can be carried out”); and
performing, by the controller and based on detecting that the clutch is experiencing slippage, an action to cause the clutch to disengage a mechanical connection (131, 132) between a first pump (110 on left in view of fig. 3) and the power source while the power source is running and is mechanically connected to a second pump (110 on right in view of fig. 3) [see ¶57: “upon the rotation speed of any one of the two plunger pumps detected by the two first rotation speed sensors 191 being not match the rotation speed of the prime mover detected by the second rotation speed sensor 192, the corresponding clutch can be controlled to disengage, thereby ensuring the normal operation of the other plunger pump”].
Zhong remains silent on the method, wherein the power is inputted to the power source “via a variable frequency drive”.
However, Coli teaches an electrically powered modular fracturing system featuring electric motors (21) paired to fluid pumps (22) on a trailer. Coli teaches that these electric motors are controlled by variable frequency drives (VFDs). Coli further states that the (see col. 11, lines 15-17) “VFDs essentially ‘tell’ the motors what they are allowed to do” by modulating and controlling the electrical input power supply parameters.
Zhong teaches (see ¶16) that the prime mover (120; asserted power source) in a fracturing apparatus includes “one of a diesel engine, an electric motor and a turbine engine”. Coli establishes (see col. 11, lines 19-20) “electrical motors controlled via VFD are far safer and easier to control than conventional diesel powered equipment”. Thus, it would have been obvious to the person of ordinary skill in the art before the effective filing date of the invention to modify the dual-pump fracturing system of Zhong for use of an electrical motor controlled via the variable frequency drive taught by Coli because “electrical motors controlled via VFD are far safer and easier to control than conventional diesel powered equipment”, as recognized by Coli above.
Zhong, as modified, remains silent on the method, wherein the power is inputted (input power supply) to the power source (electric motor) via the VFD.
Zhong, as modified, remains silent on the method, wherein the determination of the output speed of the power source is based on the voltage of the input power supply.
However, Blakely teaches (see ¶67 and fig. 4; motor is 104a, speed adjustment module is 406a) a motor controller environment, wherein the speed adjustment module determines a speed of the motor from a fundamental frequency of a voltage on the set of conductors feeding the motor. Thus, Blakely teaches a determination of the output speed of the power source based on the voltage of the input power supply.
Because both Zhong and Blakely teaches a step of determining actual output speed of motor/power source, it would have been obvious to the person of ordinary skill in the art before the effective filing date of the invention to substitute the step of determining output speed of the power source using Zhong’s sensor (192) in the modified method of Zhong for a step that determines the output speed of the power source based on the voltage of the input power supply as taught by Blakely in order to obtain the predictable result of determining the actual output speed of the power source. KSR Int’l v. Teleflex Inc., 127 S. Ct. 1727, 1740-41, 82 USPQ2d 1385, 1396 (2007).
Thus, Zhong, as modified, teaches the method, comprising: obtaining, by a controller (Zhong’s fig. 5: modified controller 230) and via a first sensor (speed adjustment module as per teaching of Blakely) coupled to a power source (electric motor), a first measurement value indicating a voltage of an input power supply (as per teaching of Blakely) to the power source (electric motor) via a variable frequency drive (as per teaching of Coli); determining by the controller, an output speed of the power source (electric motor) based on the voltage of the input power supply (as per teaching of Blakely).
In reference to claim 41, Zhong, as modified, teaches the method (see Zhong), wherein detecting that the clutch is experiencing slippage comprises:
determining a difference between the output speed of the power source and the second measurement value (see ¶55: “Therefore, upon the actual rotation speed detected by the first rotation speed sensor 191 not matching the actual rotation speed detected by the second sensor 192, for example, the transmission ratio being not conformed, it can be judged that the clutch is abnormal”); and
determining that the clutch is experiencing slippage based on the difference satisfying a threshold (threshold in this case being zero, i.e. input speed of the clutch = output speed of the clutch).
In reference to claim 42, Zhong, as modified, teaches the method (see Zhong), wherein performing the action to cause the clutch to disengage comprises: providing a signal to cause a hydraulic circuit (clutch hydraulic system 140) to provide or remove hydraulic fluid to the clutch to cause the clutch to be disengaged (see ¶45: “the fracturing apparatus can control the clutch hydraulic system through the control system to make the clutch quickly disengage”).
In reference to claim 44, Zhong, as modified, teaches the method (see Zhong), wherein detecting that the clutch is experiencing slippage comprises determining that a difference between the output speed of the power source and the second measurement value satisfies a threshold across a plurality of measurements [(see Zhong’s disclosure in ¶55) because the controller continuously tracks the values from the speed sensors 191, 192 for determining clutch abnormality; the limitation “a difference between the output speed of the power source and the second measurement value satisfies a threshold across a plurality of measurements” is met; “plurality of measurements” are obtained in real time for continuous evaluation of difference between input speed of the clutch and output speed of the clutch; if input speed = output speed then no slippage (i.e. clutch normal); if input speed ≠ output speed, then slippage present (i.e. clutch abnormal); threshold in this case being zero].
Claim 43 is rejected under 35 U.S.C. 103 as being unpatentable over Zhong in view of Coli and further in view of Blakely and Straume et al. (Us 2011/0258998 – herein after Straume).
Zhong, as modified, remains silent on the method, obtaining, after performing the action to cause the clutch to disengage, one or more additional measurement values associated with the dual-pump single-power source system; and determining, based on the one or more additional measurement values, whether the clutch is permitted to engage the mechanical connection.
However, Straume teaches a computer loop that evaluates whether input/output shaft speed deltas are “equal or zero” before allowing re-coupling [see ¶34: “The computer is programmed to calculate the flow of power (energy per time unit) which is channelled into the system at any time, based on these input data, and to disengage the slip clutch 16 when needed, and to reengage it when favourable, to protect the internal system from excessive speed, excessive forces and excessive energy input….. A number of other conditions for engagement and disengagement of the slip clutch may be programmed into the computer. The conditions for re-engaging the slip clutch need not be the exact inverse of the conditions for disengagement. If the slip clutch slips at a rotational speed value A, it may re-engage at a value E, which is lower than A or even zero”].
Zhong establishes a control system that monitors a wide array of active pump conditions – such as operating speeds and output liquid pressure – to safely trigger a disengagement and enter a baseline maintenance state. However, Zhong does not teach a precise automation logic needed to safely exit this maintenance status and re-engage. Straume teaches the logic to disengage and re-engage the clutch. In high-pressure, high torque positive displacement plunger pump environments, blindly re-engaging a clutch while the fluid end maintains a massive trapped pressure load or while a severe speed differential exists across the clutch faces would introduce catastrophic shocks and instantly destroy the drive shaft. Thus, it would have been obvious to the person of ordinary skill in the art before the effective filing date of the invention to provide the step of “obtaining, after performing the action to cause the clutch to disengage, one or more additional measurement values associated with the dual-pump single-power source system; and determining, based on the one or more additional measurement values, whether the clutch is permitted to engage the mechanical connection” in the modified method of Zhong using the teachings of Straume so that the controller does not blindly re-couple the drive train. Instead, it safely obtains additional system measurement values after the initial disengagement to verify that the fault has cleared or system pressure has dropped to a safe threshold before granting automated permission to re-couple the mechanics/clutch.
Allowable Subject Matter
Claims 30 – 34 are allowed as previously stated in the last office action.
Response to Arguments
The arguments filed 02/05/2026, with respect to dependent claims 35 and 36, have been fully considered but are partly found to be persuasive.
Applicant states “The Office Action notes that claims 35 and 36 are not examined "because the limitations of independent claim 1 (upon which the claims depend) are recited in the alternative and the rotational speed alternative has been considered in the prior art rejection of independent claim 1 below." See Office Action, page 2. Nonetheless, solely to advance prosecution and without acquiescing in the Examiner's rejection, Applicant amends claim 1 to specify that the measurement values indicate a crank angle or a phase position of an input and output shaft of the clutch. Accordingly, Applicant request that claims 35 and 36 be entered and examined”.
Claim 36 is no longer withdrawn in view of the discussion above under examiners note. However, it is to be noted that the claim 1, as amended, still recites “crank angle” and “phase position” in the alternative. Thus, as noted above under examiner’s note, claim 35 remains withdrawn.
The arguments filed 02/05/2026, with respect to dependent claim 3, have been fully considered and are partly found to be persuasive.
It is acknowledged that the last office action, inadvertently, failed to provide prior art rejection corresponding to dependent claim 3 in the detailed action. However, a request for a second non-final action is hereby denied for following reasons:
Applicant’s substantial amendment to independent claim 1 has completely changed the scope of claim 1 and, by extension, the scope of dependent claim 3. Independent claim 1, upon which claim 3 depends, has been amended substantially in order to overcome the 35 USC 102 rejection discussed in the last Non-Final office action. In particular, the conditions “a rotational speed of an input of the clutch” and “a rotational speed of an output of the clutch” have been removed completely in the amended independent claim 1 for overcoming its corresponding 35 USC 102 rejection. This substantial change resulted in scope change for both independent claims 1 and 3. Thus, a Final-Rejection is hereby issued in view of new grounds of rejection discussed in this Office Action.
As per MPEP 706.07(a) “Second or any subsequent actions on the merits shall be final, except where the examiner introduces a new ground of rejection that is neither necessitated by applicant’s amendment of the claims, nor based on information submitted in an information disclosure statement filed during the period set forth in 37 CFR 1.97(c) with the fee set forth in 37 CFR 1.17(p)…”. Had Applicant kept claim 1 exactly as originally presented, a new rejection of claim 3 would require a Non-Final action due to the Examiner’s omission. However, because Applicant chose to significantly alter the structural baseline of claim 1 (and thus the underlying limitations of dependent claim 3), the Examiner must now look to entirely new prior art teachings or formulations to address the narrowed boundaries of “a crank angle or a phase position of an output shaft of the clutch”. Because the current grounds of rejection are entirely necessitated by Applicant’s amendment, the issuance of this Final Action is procedurally correct and proper.
The arguments filed 02/05/2026, with respect to independent claim 1 rejected under 35 USC 102, have been fully considered but are moot. The amendment to independent claim 1 changed the scope of the claim. As a result, the prior arts have been re-evaluated and re-applied to claim 1, in view of newly relied upon reference of Schafer.
The arguments filed 02/05/2026, with respect to independent claim 40 rejected under 35 USC 103, have been fully considered but are moot. The amendment to independent claim 40 changed the scope of the claim. As a result, the prior arts have been re-evaluated and re-applied to claim 40, in view of newly relied upon reference of Coli and Blakely.
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
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/CHIRAG JARIWALA/Examiner, Art Unit 3746
/ESSAMA OMGBA/Supervisory Patent Examiner, Art Unit 3746
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