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 .
Information Disclosure Statement
The information disclosure statement (IDS) submitted on 06/12/2026 has been considered by the examiner.
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.
Claim(s) 1 and 2 is/are rejected under 35 U.S.C. 103 as being unpatentable over Lei (CN105421509) view of Katsuharu (JP2008095788).
Lei discloses:
[Claim 1] A work machine comprising:
a boom (boom coupled to boom cylinder 1);
a boom cylinder (1) including a bottom chamber (1b) and a head chamber (1a);
a boom pump (11) including a suction port and a discharge port;
a hydraulic oil tank (reservoir downstream valve 13, see Fig. 2);
a boom operation valve (4) including a pump port (P) connected to the discharge port via a pump line,
a bottom port (A) connected to the bottom chamber via a bottom line,
a head port (B) connected to the head chamber via a head line,
a tank port (T) connected to the hydraulic oil tank via a tank line, and
a regenerative port (D) connected to the suction port via a regenerative line (14);
an accumulator (16) connected to the regenerative line via an accumulator line;
a controller (7a, 7b) that controls the boom operation valve so that hydraulic oil emitted from the bottom chamber is distributed to the suction port in a lowering operation of the boom (when valve 4 is controlled to be energy recovery position, chamber 1b is connected to line 14 which is connected to the suction port of pump 11 and an accumulator 16).
Lei does not disclose an accumulator switching valve that adjusts a flow rate of hydraulic oil in the accumulator line.
However, Katsuharu discloses a work machine including energy recovery from lowering of a boom similar to Lei and the present application and therefore constitutes analogous art. Katsuharu discloses a work machine comprising:
a boom (see Fig. 1);
a boom cylinder (8) including a bottom chamber (8a) and a head chamber (8b);
a boom pump (9) including a suction port and a discharge port;
a hydraulic oil tank (10);
a boom operation valve (11) including a pump port connected to the discharge port via a pump line (see annotated Katsuharu Fig. 2'),
a bottom port connected to the bottom chamber via a bottom line (see annotated Katsuharu Fig. 2'),
a head port connected to the head chamber via a head line (see annotated Katsuharu Fig. 2'),
a tank port connected to the hydraulic oil tank via a tank line (see annotated Katsuharu Fig. 2'), and
a regenerative port connected to the suction port (see annotated Katsuharu Fig. 2') via a regenerative line (12);
an accumulator (17) connected to the regenerative line via an accumulator line (18);
an accumulator switching valve (19) that adjusts a flow rate of hydraulic oil in the accumulator line; and
a controller (20) that controls the boom operation valve and the accumulator switching valve so that hydraulic oil emitted from the bottom chamber is distributed to each of the suction port and the accumulator in a lowering operation of the boom (paragraph [0012] discloses that controller 20 controls valve 19 which controls the inflow and outflow of fluid to the accumulator 17; paragraph [0015] discloses distributing fluid to both the accumulator 17 via valve 19 and the regenerative motor 13 which then flows to the reservoir 11 and then to suction port 9; therefore the bottom chamber fluid is distributed to both the accumulator and the suction port of the pump).
Katsuharu teaches that accumulator switching valve 19 facilitates energy recovery during lowering of the boom by selectively controlling the flow into and out of the accumulator (paragraph [0014] recites “a control signal is output to the electromagnetic proportional switching valve 19B to control the input / output flow rate to the accumulator 17.”; Paragraph [0018] recites “As a result, when the lowering speed of the boom 5 is fast and the discharge flow rate from the head-side oil chamber 8a is large, a part of the discharge flow rate is accumulated in the accumulator 17 disposed on the upstream side of the regeneration hydraulic motor 13”). One of ordinary skill in the art would recognize that the valve 19 allows the fluid energy stored in the accumulator 17 to be selectively utilized as needed which is suitable for the system of Lei that aims to use the stored energy at the right time as indicated in the discussion of its embodiment 2 paragraph.
Since the ability to store energy in the accumulator during lowering of a boom for selective usage is beneficial, it would have been obvious to one of ordinary skill in the art at the time the invention was filed to have modified the system of Lei to have used an accumulator switching valve that adjusts a flow rate of hydraulic oil in the accumulator line, including its associated control configured so that hydraulic oil emitted from the bottom chamber is distributed to each of the suction port and the accumulator in a lowering operation of the boom as taught by Katsuharu. When implementing the accumulator switching valve of Katsuharu into the system of Lei, the accumulator switching valve would cause some boom cylinder return fluid to flow into the accumulator and some boom cylinder return fluid to flow into the suction port of the pump.
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Claim(s) 2 is/are rejected under 35 U.S.C. 103 as being unpatentable over Lei in view of Katsuharu as applied to claim 1 above, and further in view of Stephenson et al. (US 7905088), hereinafter ‘Stephenson’.
Regarding claim 2, the combination of Lei in view of Katsuharu renders obvious the work machine according to claim 1, but does not explicitly disclose wherein the controller controls the boom operation valve and the accumulator switching valve so that hydraulic oil discharged from the discharge port is supplied to the bottom chamber and hydraulic oil is supplied from the accumulator to the suction port in a raising operation of the boom.
However, Stephenson discloses a hydraulic system including boom energy recovery similar to Lei and the present application and therefore constitutes analogous art. Stephenson discloses boom cylinders (16, 17) recovering energy during a boom lowering operation by directing fluid from the boom bottom chamber (34, 38) into accumulator (60) via valve (62), and selectively using the stored energy in the accumulator (60) by directing the stored fluid to the suction port of the boom pump (22) through valve (68). Stephenson (Col 6 lines 44-54) states that routing stored pressurized fluid from the accumulator to the inlet of the pump (22) is particularly useful when the inlet of the pump has a high pressure inlet capability and allows energy recovery to unload the toque on the engine that drives the pump (22) so that the engine only needs an amount of torque that fulfills the pressure difference between the accumulator(60) and the load pressure on the cylinder assemblies. One of ordinary skill in the art would recognize that a high load operation would be a lifting operation of the boom cylinder in which the pump supplies fluid to the bottom chamber of the boom hydraulic cylinders.
Since Lei already discloses using the stored energy in the accumulator “when the system needs it”, and since Stephenson discloses that boom raising operations are known to supplemental energy from accumulators to assist a pump in a raising operation, it would have been obvious to one of ordinary skill in the art at the time the invention was filed to have further modified the system of Lei in view of Katsuharu to have the controller controls the boom operation valve and the accumulator switching valve so that hydraulic oil discharged from the discharge port is supplied to the bottom chamber and hydraulic oil is supplied from the accumulator to the suction port in a raising operation of the boom as rendered obvious by Stephenson.
Claim(s) 3 is/are rejected under 35 U.S.C. 103 as being unpatentable over Lei in view of Katsuharu as applied to claim 1 above, and further in view of Matsuzaki et al. (US 10604916), hereinafter ‘Matsuzaki’.
Regarding claim 3, the combination of Lei and Katsuharu renders obvious the work machine according to claim 1 and further renders obvious a main actuator (Lei, 2 or 3), but does not disclose a main hydraulic pump that is connected to the boom pump and discharges hydraulic oil for actuating the main hydraulic actuator, wherein in a lowering operation of the boom, a rotational energy of the boom pump is transmitted to the main hydraulic pump.
However, Matsuzaki discloses a hydraulic system including boom hydraulic cylinder energy recovery similar to Lei and the present application and therefore constitutes analogous art. Matsuzaki discloses a main hydraulic actuator (8 or 9); and a main hydraulic pump (14L) that is connected to the boom pump and discharges hydraulic oil for actuating the main hydraulic actuator, wherein in a lowering operation of the boom, a rotational energy of the boom pump is transmitted to the main hydraulic pump (Fig. 14, return fluid from boom cylinder 7 is directed to pump/motor 14A which converts the fluid energy to rotational energy that is transmitted to main pump 14L which supplies fluid to main actuator 8, Col. 26 lines 61-67, Col. 27 lines 1-4). Matsuzaki teaches that this energy reutilization technique allows for the load on the engine to be reduced and thus also reduces an amount of fuel injection.
Since reduced engine load and fuel usage is beneficial, it would have been obvious to one of ordinary skill in the art at the time the invention was filed to have further modified the system of Lei in view of Katsuharu to have used an additional pump to drive hydraulic actuators other than the boom cylinder, such that a main hydraulic actuator; and a main hydraulic pump that is connected to the boom pump and discharges hydraulic oil for actuating the main hydraulic actuator, wherein in a lowering operation of the boom, a rotational energy of the boom pump is transmitted to the main hydraulic pump as taught by Matsuzaki. Since Lei already discloses a boom pump that uses energy recovered from a lowering operation of its boom cylinder, when implementing the teachings of Matsuzaki, the boom pump (Lei 11) of Lei would be driven by the return fluid from the boom cylinder (Lei 1) and would transmit rotational energy to additional implemented pumps that drive the other actuators (Lei, actuators 2 and 3) which would result in the disclosed benefit of reduced engine load and reduced fuel usage.
Claim(s) 1 is/are rejected under 35 U.S.C. 103 as being unpatentable over Katsuharu (JP2008095788) in view of Kondo (US 2018/0291935).
Katsuharu discloses:
[Claim 1] A work machine comprising:
a boom (see Fig. 1);
a boom cylinder (8) including a bottom chamber (8a) and a head chamber (8b);
a boom pump (9) including a suction port and a discharge port;
a hydraulic oil tank (10);
a boom operation valve (11) including a pump port connected to the discharge port via a pump line (see annotated Katsuharu Fig. 2'),
a bottom port connected to the bottom chamber via a bottom line (see annotated Katsuharu Fig. 2'),
a head port connected to the head chamber via a head line (see annotated Katsuharu Fig. 2'),
a tank port connected to the hydraulic oil tank via a tank line (see annotated Katsuharu Fig. 2'), and
a regenerative port connected to the suction port (see annotated Katsuharu Fig. 2') via a regenerative line (12);
an accumulator (17) connected to the regenerative line via an accumulator line (18);
an accumulator switching valve (19) that adjusts a flow rate of hydraulic oil in the accumulator line; and
a controller (20) that controls the boom operation valve and the accumulator switching valve so that hydraulic oil emitted from the bottom chamber is distributed to each of the suction port and the accumulator in a lowering operation of the boom (paragraph [0012] discloses that controller 20 controls valve 19 which controls the inflow and outflow of fluid to the accumulator 17; paragraph [0015] discloses distributing fluid to both the accumulator 17 via valve 19 and the regenerative motor 13 which then flows to the reservoir 11 and then to suction port 9; therefore the bottom chamber fluid is distributed to both the accumulator and the suction port of the pump).
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Katsuharu does not explicitly state that the controller 20 controls the boom control valve 11.
However, Kondo discloses a work machine similar to Katsuharu and the present application and therefore constitutes analogous art. Kondo discloses a work machine including a controller that controls the boom control valve in accordance with signals from a boom operation lever (paragraph [0058-0063]). Kondo further discloses a work machine comprising: a boom (see Fig. 2);
a boom cylinder (11) including a bottom chamber and a head chamber;
a boom pump (14) including a suction port and a discharge port;
a hydraulic oil tank (21);
a boom operation valve (3) including a pump port connected to the discharge port via a pump line,
a bottom port connected to the bottom chamber via a bottom line (11a),
a head port connected to the head chamber via a head line (11b),
a regenerative port connected to the suction port via a regenerative line (51);
a controller (7) that controls the boom operation valve (11) so that hydraulic oil emitted from the bottom chamber is distributed to each of the suction port (paragraph [0058]-[0063] discloses a controller receiving signals from boom operation lever 45 and controlling the boom control valve 3 accordingly).
It is obvious to combine prior art elements according to known methods to yield predictable results. See MPEP 2143(A). The MPEP states the prior art must: (1) teach each claimed element (a method or apparatus that will be modified), (2) show that one of ordinary skill in the art could have combined the elements by known methods and that the combination doesn’t change the function of the elements, and (3) show that one of ordinary skill would have recognized that applying the known technique to the base device would yield predictable results. See MPEP 2143(A).
In this case, Katsuharu teaches all elements except a controller that controls the boom operation valve. Kondo teaches a controller that controls the boom operation valve, which has the function of controlling the boom operation valve in accordance with the boom operation lever signals. When combined into Katsuharu by using the existing controller 20 to control the boom operation valve, it maintains its function of controlling the boom operation valve in accordance with the boom operation lever signals. One of ordinary skill would expect predictable results because both references pertain to boom operation valve control that function in the same manner in the environment of work vehicles including hydraulic boom systems.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the system of Katsuharu in view of Kondo because all the claimed elements were known in the prior art and one skilled in the art could have combined the elements as claimed by known methods with no change in their respective functions, and the combination yielded nothing more than predictable results to one of ordinary skill in the art.
Allowable Subject Matter
Claims 3 and 5 are objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims.
The following is a statement of reasons for the indication of allowable subject matter:
The prior art does not appear to disclose the limitations of claims 3 or 5 in combination with their base claim limitations.
Claim 3 requires considering a cross-sectional area ratio between the bottom chamber and the head chamber in a distribution ratio. While prior art reference Katsuharu discloses a distribution ratio between fluid flow to the accumulator and a hydraulic recovery motor (fluid reaches the suction port through the regenerative motor and reservoir), the cross-sectional area ratio of the boom cylinder is not considered.
Claim 5 requires the controller to control a swash plate angle of the boom pump and an opening area of the accumulator switching valve so that a ratio between a rotation speed of the boom pump and an expansion/contraction speed of the boom cylinder becomes constant based on an engine rotation speed indicating a rotation speed of the engine and a lever angle indicating an operation angle of the operation lever in a lowering operation of the boom. While swash plate angle control and valve opening of the accumulator switching valve is known in the prior art, the specified control to achieve a constant speed of the boom cylinder based on an engine rotation speed and lever angle does not appear to be disclose nor rendered obvious in the prior art.
Conclusion
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/DUSTIN T NGUYEN/Primary Examiner, Art Unit 3745 July 16, 2026
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