DETAILED ACTION
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 .
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.
Claims 1 & 3-4 are rejected under 35 U.S.C. 103 as being unpatentable over Cheng et al (12025158) in view of Kuramoto (6050918).
Cheng et al disclose a pump control device for controlling a delivery capacity of a variable displacement pump (e.g. 2) in a fluid pressure control system (e.g. Fig. 1), the fluid pressure control system comprising the pump configured to deliver hydraulic fluid to a fluid pressure actuator (e.g. 4-1) through a supply passage (e.g. extending from pump 2 through valve 3-1), and a control valve (e.g. 3-1) configured to control a flow of the hydraulic fluid supplied to and discharged from the fluid pressure actuator in accordance with an operation inlet (e.g. 7) by an operator for driving the fluid pressure actuator, the pump control device comprising: a discharge passage (e.g. branch from supply line beyond 3-2/8-2 connected to input of 9) configured to guide the hydraulic fluid in the supply passage to a tank; a discharge control unit configured to control the flow of the hydraulic fluid discharged to the tank through the discharge passage; and a controller (e.g. 13) configured to control the delivery capacity of the pump and operation of the discharge control unit in accordance with the operation input by the operator, wherein the discharge control unit has: a relief valve (e.g. 9) provided in the discharge passage, the relief valve being configured to be opened when a pressure in the discharge passage reaches a predetermined valve opening pressure (e.g. spring and load pressure), the relief valve being configured such that the valve opening pressure is variable (e.g. due to load pressure); a resistance portion (e.g. 12) configured to apply resistance to the flow of the hydraulic fluid guided from the supply passage to the discharge passage and passed through the relief valve; and a pressure measurement unit (e.g. 10, 11) configured to acquire an upstream-downstream differential pressure across the resistance portion, and wherein the controller is configured to: store (e.g. Fig. 8, S2), in advance, a pressure-flow amount characteristic that is a relationship between a pressure and a passing flow amount in the resistance portion; acquire (e.g. Fig. 8, S2) the flow amount of the hydraulic fluid passing through the resistance portion based on the pressure-flow amount characteristic of the resistance portion and the upstream-downstream differential pressure acquired by the pressure measurement unit; and change (e.g. Fig. 8, ) at least one of the delivery capacity of the pump and the valve opening pressure of the relief valve in accordance with the flow amount of the hydraulic fluid passing through the resistance portion.
Cheng et al do not teach that the relief valve being configured such that the valve opening pressure is variable in accordance with an input electrical signal.
Kuramoto teaches a relief valve being configured such that the valve opening pressure is variable in accordance with an input electrical signal (e.g. Fig. 6, 6) positioned in a discharge line (e.g. 5).
It is well known to sample, and feedback, load pressure in a control system using an electrical signal. Cheng et al and Kuramoto all seek to control a pump capacity using a relief valve in a discharge line, thus it would have been obvious to one having ordinary skill in the art at the time the invention was filed to modify the system of Cheng et al to have the relief valve configured such that the valve opening pressure is variable in accordance with an input electrical signal, as taught by Kuramoto, for the purpose of feeding back load pressure to the relief valve.
Cheng et al, as modified, further teach the controller is configured to, with an increase in the flow amount of the hydraulic fluid passing through the resistance portion, increase the valve opening pressure of the relief valve and reduce the delivery capacity of the pump (e.g. Fig. 7, Col. 8, Ln. 3-18); and the pressure measurement unit further comprises: an upstream pressure measurement unit (e.g. 10) configured to measure a pressure of the hydraulic fluid guided from the relief valve to the resistance portion; and a tank pressure measurement unit (e.g. 11) configured to measure a pressure in the tank, and the controller acquires the flow amount of the hydraulic fluid passing through the resistance portion based on a differential pressure between the pressure measured by the upstream pressure measurement unit and the pressure measured by the tank pressure measurement unit.
Claims 5-6 are rejected under 35 U.S.C. 103 as being unpatentable over Cheng et al (12025158) in view of Kuramoto (6050918) and Honda et al (10233613).
Cheng et al disclose a fluid pressure control system (e.g. Fig. 1) for controlling operation of a fluid pressure actuator (e.g. 4-1), the fluid pressure control system comprising: a variable displacement pump (e.g. 2) configured to deliver hydraulic fluid through a supply passage (e.g. extending from pump 2 through valve 3-1); a control valve (e.g. 3-1, Fig. 3); and a pump control device configured to control a delivery capacity of the pump, wherein the pump control device has: a discharge passage (e.g. branch from supply line beyond 3-2/8-2 connected to input of 9) configured to guide the hydraulic fluid in the supply passage to the tank; a discharge control unit configured to control the flow of the hydraulic fluid discharged to the tank through the discharge passage; and a controller (e.g. 13) configured to control the delivery capacity of the pump and operation of the discharge control unit in accordance with the operation input by the operator for operating the fluid pressure actuator, the discharge control unit has: a relief valve (e.g. 9) provided in the discharge passage, the relief valve being configured to be opened when a pressure in the discharge passage reaches a predetermined valve opening pressure (e.g. spring and load pressure), the relief valve being configured such that the valve opening pressure is variable (e.g. due to load pressure); a resistance portion (e.g. 12) configured to apply resistance to the flow of the hydraulic fluid guided from the supply passage to the discharge passage and passed through the relief valve; and a pressure measurement unit (e.g. 10, 11) configured to acquire an upstream-downstream differential pressure across the resistance portion, and wherein the controller is configured to: store (e.g. Fig. 8, S2), in advance, a pressure-flow amount characteristic that is a relationship between a pressure loss and a passing flow amount in the resistance portion; acquire (e.g. Fig. 8, S2) the flow amount of the hydraulic fluid passing through the resistance portion based on the pressure-flow amount characteristic of the resistance portion and the upstream-downstream differential pressure acquired by the pressure measurement unit; and change (e.g. Fig. 8, S3) at least one of the delivery capacity of the pump and the valve opening pressure of the relief valve in accordance with the flow amount of the hydraulic fluid passing through the resistance portion.
Cheng et al do not explicitly teach; or the relief valve being configured such that the valve opening pressure is variable in accordance with an input electrical signal.
Honda et al teach a control valve (e.g. Fig. 3, 170 ) having a neutral position (e.g. centered position) at which the hydraulic fluid delivered from the pump (e.g. 14L) is guided to a tank (e.g. T) at a neutral state with no operation input by an operator, the control valve being configured to control a flow of the hydraulic fluid supplied to and discharged from the fluid pressure actuator in accordance with an operation input
Kuramoto teaches a relief valve being configured such that the valve opening pressure is variable in accordance with an input electrical signal (e.g. Fig. 6, 6) positioned in a discharge line (e.g. 5).
The type of direction control valve (i.e. Fig. 3, 15) of Cheng et al is not specified, however it is known to use an open-center direction control valve in a fluid pressure control system. Further, it is well known to sample, and feedback, load pressure in a control system using an electrical signal. Cheng et al, Kuramoto and Honda et al all seek to provide a fluid pressure control system for controlling operation of a fluid pressure actuator, thus it would have been obvious to one having ordinary skill in the art at the time the invention was filed to modify the system of Cheng et al such that the control valve having a neutral position at which the hydraulic fluid delivered from the pump is guided to a tank at a neutral state with no operation input by an operator, the control valve being configured to control a flow of the hydraulic fluid supplied to and discharged from the fluid pressure actuator in accordance with the operation input, as taught by Honda et al, for the purpose of controlling the flow of fluid to the actuator; and such that the relief valve is configured such that the valve opening pressure is variable in accordance with an input electrical signal, as taught by Kuramoto, for the purpose of feeding back load pressure to the relief valve.
Cheng et al, as modified, further teach the control valve has an operating position at which the supply passage and the fluid pressure actuator are communicated, and a communication between the supply passage and the tank is shut off in the operating position (e.g. Fig. 3 of Honda et al).
Claim 7 is rejected under 35 U.S.C. 103 as being unpatentable over Cheng et al (12025158) in view of Fukuda et al (9080582) and Kuramoto (6050918).
Cheng et al disclose a pump control device for controlling a delivery capacity of a variable displacement pump (e.g. 2) in a fluid pressure control system (e.g. Fig. 1), the fluid pressure control system comprising the pump configured to deliver hydraulic fluid to a fluid pressure actuator (e.g. 4-1) through a supply passage (e.g. extending from pump 2 through valve 3-1), and a control valve (e.g. 3-1) configured to control a flow of the hydraulic fluid supplied to and discharged from the fluid pressure actuator in accordance with an operation inlet (e.g. 7) by an operator for driving the fluid pressure actuator, the pump control device comprising: a discharge passage (e.g. branch from supply line beyond 3-2/8-2 connected to input of 9) configured to guide the hydraulic fluid in the supply passage to a tank; a discharge control unit configured to control the flow of the hydraulic fluid discharged to the tank through the discharge passage; and a controller (e.g. 13) configured to control the delivery capacity of the pump and operation of the discharge control unit in accordance with the operation input by the operator, wherein the discharge control unit has: a relief valve (e.g. 9) provided in the discharge passage, the relief valve being configured to be opened when a pressure in the discharge passage reaches a predetermined valve opening pressure (e.g. spring and load pressure), the relief valve being configured such that the valve opening pressure is variable (e.g. due to load pressure); a resistance portion (e.g. 12) provided in the discharge passage; and a pressure measurement unit (e.g. 10, 11) configured to acquire an upstream-downstream differential pressure across the resistance portion, and wherein the controller is configured to: store (e.g. Fig. 8, S2), in advance, a pressure-flow amount characteristic that is a relationship between a pressure and a passing flow amount in the resistance portion; acquire (e.g. Fig. 8, S2) the flow amount of the hydraulic fluid passing through the resistance portion based on the pressure-flow amount characteristic of the resistance portion and the upstream-downstream differential pressure acquired by the pressure measurement unit; and change (e.g. Fig. 8, ) at least one of the delivery capacity of the pump and the valve opening pressure of the relief valve in accordance with the flow amount of the hydraulic fluid passing through the resistance portion.
Cheng et al do not teach that the resistance portion being configured to apply resistance to the flow of the hydraulic fluid flowing from the supply passage to the relief valve; or the relief valve being configured such that the valve opening pressure is variable in accordance with an input electrical signal.
Fukuda et al teach a pump control device, for a fluid pressure control system (e.g. Fig. 1), including a discharge control unit (e.g. S) having a resistance portion (e.g. 7, Col. 3, Ln. 4-18) provided in a discharge passage (e.g. 6), the resistance portion being configured to apply resistance to the flow of the hydraulic fluid flowing from the supply passage to a relief valve (e.g. 8).
Kuramoto teaches a relief valve being configured such that the valve opening pressure is variable in accordance with an input electrical signal (e.g. Fig. 6, 6) positioned in a discharge line (e.g. 5).
Cheng et al in that locates the resistance portion upstream of the relied valve. It is well known to sample, and feedback, load pressure in a control system using an electrical signal. Cheng et al, Fukuda et al, and Kuramoto all seek to provide a fluid pressure control system for controlling of a fluid pressure actuator, thus it would have been obvious to one having ordinary skill in the art at the time the invention was filed to modify the system of Cheng et al to have the resistance portion being configured to apply resistance to the flow of the hydraulic fluid flowing from the supply passage to the relief valve, as taught by Fukuda et al, for the purpose of controlling the flow of fluid to the relief valve, and further to have the relief valve configured such that the valve opening pressure is variable in accordance with an input electrical signal, as taught by Kuramoto, for the purpose of feeding back load pressure to the relief valve.
Allowable Subject Matter
Claim 2 is 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.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. Additional references listed on form PTO-892 are cited for their relevance to the disclosed invention and demonstration of the state of the art.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to MICHAEL LESLIE whose telephone number is (571)272-4819. The examiner can normally be reached M - F 8 am - 4-30pm.
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/MICHAEL LESLIE/
Primary Examiner, Art Unit 3745
September 25, 2026
