# US 10,870,969 B2 · Hydraulic system for working machine > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,870,969 B2 - Document ID: US10870969B2 - Status: Granted - Kind: B2 - Application number: 16/158,651 - Filed: 2018-10-12 - Published: 2019-04-18 - Granted: 2020-12-22 - Earliest claimed: 2017-10-16 - Assignees: Kubota Corporation - Applicants: Kubota Corporation - Inventors: Yuji Fukuda - Web page: https://patentgrep.com/patent/US10870969B2 ## CPC - E02F 9/2246: {Control of prime movers, e.g. depending on the hydraulic load of work tools} - E02F 3/3414: {the arms being pivoted at the rear of the vehicle chassis, e.g. skid steer loader} - F04B 49/06: Control using electricity (regulating by means of floats actuating electric switches F04B49/04) - F04B 49/08: Regulating by delivery pressure - F04B 49/22: by means of valves (F04B49/03 takes precedence) - E02F 9/2221: {Control of flow rate; Load sensing arrangements (E02F9/2203 take precedence over E02F9/2221)} - F04B 2205/09: Flow through the pump - F15B 2211/20515: Electric motor - F15B 2211/20523: Internal combustion engine - F15B 2211/255: Flow control functions - F15B 2211/30525: Directional control valves, e.g. 4/3-directional control valve - F15B 2211/3056: Assemblies of multiple valves - F15B 2211/6316: the pressure being a pilot pressure - F15B 2211/6651: Control of the prime mover, e.g. control of the output torque or rotational speed - F15B 2211/70: Output members, e.g. hydraulic motors or cylinders or control therefor - E02F: DREDGING; SOIL-SHIFTING (winning peat E21C49/00) - F04B: POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS (machines for liquids, or pumps, of rotary-piston or oscillating-piston type F04C; non-positive-displacement pumps F04D; pumping of fluid by direct contact of another fluid or by using inertia of fluid to be pumped F04F) - F15B: SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR ## Abstract A hydraulic system for a working machine, includes a first hydraulic pump to output an operation fluid, a hydraulic device to be operated by the operation fluid, an operation member to be operated, a control valve to control the hydraulic device based on an operation extent of the operation member, a holding member to set a held operation extent that is the operation extent held in the operation of the operation member, and a pedal to be operated to change the held operation extent set by the holding member. ## Claims ### Claim 1 A hydraulic system for a working machine, comprising: a first hydraulic pump to output an operation fluid; a hydraulic device to be operated by the operation fluid; an operation member to be manually operated for changing an operation extent; a switch to switch between a first operation that holds the operation extent to a predetermined held operation extent and a second operation that does not hold the operation extent to the held operation extent; a pedal to be operated for changing the held operation extent upon the first operation of the switch; a control valve to control the hydraulic device based on the held operation extent when the switch is switched to the first operation and the held operation extent is not changed by the pedal, based on the held operation extent after being changed by the pedal when the switch is switched to the first operation and the held operation extent is changed by the pedal, and based on the operation extent when the switch is switched to the second operation. ### Claim 2 (depends on 1) The hydraulic system according to claim 1, further comprising: a controller to control the control valve so that the control valve controls the hydraulic device based on the held operation extent after being changed by the pedal and thereby reduces a flow rate of the operation fluid that is supplied to the hydraulic device, when the switch is switched to the first operation and the held operation extent is changed by the pedal. ### Claim 3 (depends on 1) The hydraulic system according to claim 1, comprising a lamp to be lighted when the held operation extent is set. ### Claim 4 A hydraulic system for a working machine comprising: a first hydraulic pump to output an operation fluid; a hydraulic device to be operated by the operation fluid; an operation member to be manually operated for changing an operation extent; a switch to switch between a first operation that holds the operation extent to a predetermined held operation extent and a second operation that does not hold the operation extent to the held operation extent; a pedal to be operated, the pedal being other than the operation member; a controller to change the held operation extent based on operation of the pedal; and a control valve to control the hydraulic device based on the held operation extent when the switch is switched to the first operation and the held operation extent is not changed by the pedal, based on the held operation extent after being changed by the pedal when the switch is switched to the first operation and the held operation extent is changed by the pedal, and based on the operation extent when the switch is switched to the second operation. ### Claim 5 (depends on 4) The hydraulic system according to claim 4, wherein the controller controls the control valve so that the control valve controls the hydraulic device based on the held operation extent after being changed by the pedal and thereby reduces a flow rate of the operation fluid that is supplied to the hydraulic device, when the switch is switched to the first operation and the held operation extent is changed by the pedal. ### Claim 6 (depends on 5) The hydraulic system according to claim 5, comprising a lamp to be lighted when the held operation extent is set. ### Claim 7 (depends on 4) The hydraulic system according to claim 4, comprising a lamp to be lighted when the held operation extent is set. ### Claim 8 A hydraulic system for a working machine comprising: a first hydraulic pump to output an operation fluid; a second hydraulic pump to output the operation fluid, the second hydraulic pump being other than the first hydraulic pump; a hydraulic device to be operated by the operation fluid; a first fluid tube connecting the hydraulic device to a control valve; a second fluid tube connected to the second hydraulic pump and connected to the first fluid tube; a switching valve arranged in the second fluid tube, the switching valve having a first position and a second position, the first position blocking the operation fluid from flowing in the second fluid tube, the second position allowing the operation fluid to flow in the second fluid tube; a switching member to switch the switching valve between the first position and the second position; and a pedal to switch the switching valve from the second position to the first position from a state in which the switching valve is held at the second position by operation of the switching member. ### Claim 9 (depends on 8) The hydraulic system according to claim 8, wherein the switching valve is held at the second position when the switching member is operated. ### Claim 10 A hydraulic system for a working machine comprising: a first hydraulic pump to output an operation fluid; a second hydraulic pump to output the operation fluid, the second hydraulic pump being other than the first hydraulic pump; a hydraulic device to be operated by the operation fluid; a first fluid tube connecting the hydraulic device to a control valve; a second fluid tube connected to the second hydraulic pump and connected to the first fluid tube; a switching valve arranged in the second fluid tube, the switching valve having a first position and a second position, the first position blocking the operation fluid from flowing in the second fluid tube, the second position allowing the operation fluid to flow in the second fluid tube; a switching member to switch the switching valve between the first position and the second position; and a pedal to be operated, wherein a controller switches the switching valve from the second position to the first position when the pedal is operated under a state in which the switching valve is held at the second position by operation of the switching member. ### Claim 11 (depends on 10) The hydraulic system according to claim 10, wherein the switching valve is held at the second position when the switching member is operated.