US3628424A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hydraulic power circuits employing remotely controlled directional control valves
Assignee: SPX Technologies Inc
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Filing: 1970-05-14
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Granted: 1971-12-21
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Expires: 1990-05-14
Abstract
Abstract Hydraulic power circuit in which each actuating cylinder is controlled by an open center, pilot-operated directional control valve which is operated by a low-pressure remote control system utilizing fluid taken from the same pump which supplies motive fluid for the cylinders. The fluid which is supplied to the pilot valves of the remote control system at a reduced pressure is drawn from the supply path for the directional control valves at a point upstream of a throttle valve. This valve is automatically controlled so that it assumes a low flow-restricting position when the pilot valves, and consequently the directional control valves, are in neutral position, and assumes a high flowrestricting position whenever one of the pilot valves is shifted away from neutral position. An override control, which responds to supply pressure, shifts the throttle valve to low flowrestricting position during actuation of a cylinder.
Inventors
- 👤 Waldo G Fruehauf
- 👤 Robert W Rue
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 14:30
CPC Classifications
F; F15; F15B; F15B13/00; F15B13/02; F15B13/04; F15B13/042; F15B13/0422; Y; Y10; Y10T; Y10T137/00; Y10T137/8593; Y10T137/87169; Y10T137/87177; Y10T137/87185
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
276 words
In a hydraulic poweR circuit including an actuating motor (1); directional control valve means (3) connected with the actuating motor (1), a supply pump (6) and a fluid reservoir (5) and adapted to control flow from the pump to the motor and flow from the motor to the reservoir, the valve means having a neutral, open center condition and being actuated by fluid pressure motor means (11, 12); and a pilot valve (15) for supplying variable pilot pressures to said fluid pressure motor means and having a neutral position in which it causes that motor means to set the directional control valve means to neutral condition, the improvement which comprises a. throttle valve means (35) interposed in the supply connection (8) between the pump (6) and the directional control valve means (3) and affording high and low flow-restricting conditions; b. actuating means (36, 38, 41-44) responsive to movement of the pilot valve (15) for setting the throttle valve means (35) to the low flow-restricting condition when the pilot valve is in neutral position and for setting the throttle valve means to the high flow-restricting condition when the pilot valve is shifted away from neutral position; c. override means (45, 46) responsive to the pressure in said supply connection (8) for overriding the actuating means and setting the throttle valve means (35) to the low flowrestricting position when the pressure exceeds a predetermined value; and d. means (17, 17a), including a pressure reducer (31), for delivering fluid under pressure to the pilot valve (15) from a point (8a) in said supply connection (8) at which the pressure varies with the condition of the throttle valve means 35.
Claim 2
Dependent Claim
276 words
In a hydraulic poweR circuit including an actuating motor (1); directional control valve means (3) connected with the actuating motor (1), a supply pump (6) and a fluid reservoir (5) and adapted to control flow from the pump to the motor and flow from the motor to the reservoir, the valve means having a neutral, open center condition and being actuated by fluid pressure motor means (11, 12); and a pilot valve (15) for supplying variable pilot pressures to said fluid pressure motor means and having a neutral position in which it causes that motor means to set the directional control valve means to neutral condition, the improvement which comprises a. throttle valve means (35) interposed in the supply connection (8) between the pump (6) and the directional control valve means (3) and affording high and low flow-restricting conditions; b. actuating means (36, 38, 41-44) responsive to movement of the pilot valve (15) for setting the throttle valve means (35) to the low flow-restricting condition when the pilot valve is in neutral position and for setting the throttle valve means to the high flow-restricting condition when the pilot valve is shifted away from neutral position; c. override means (45, 46) responsive to the pressure in said supply connection (8) for overriding the actuating means and setting the throttle valve means (35) to the low flowrestricting position when the pressure exceeds a predetermined value; and d. means (17, 17a), including a pressure reducer (31), for delivering fluid under pressure to the pilot valve (15) from a point (8a) in said supply connection (8) at which the pressure varies with the condition of the throttle valve means 35.
Claim 3
Dependent Claim
143 words
The improved hydraulic power circuit defined in claim 1 in which the actuating means comprises a. means (36) biasing the throttle valve means (35) to the high flow-restricting condition; b. a valve-actuating motor (38) adapted to shift the throttle valve means (35) to the low flow-restricting condition; c. a restricted flow passage (41) connecting the valve-actuating motor (38) with a point (39) in the supply connection (8) at which the pressure varies with the condition of the throttle valve means (35); d. an exhaust passage (42) leading from the valve-actuating motor (38) to the reservoir (5); and e. a vent valve (24, 43, 44) operated in unison with the pilot valve (15) and serving to close the exhaust passage (42) when the pilot valve is in neutral position and to open that passage when the pilot valve is shifted away from neutral position.
Claim 4
Dependent Claim
66 words
The improved hydraulic circuit defined in claim 2 in which the override means comprises a. a second valve-actuating motor (45) arranged to shift the throttle valve means (35) toward the low flow-restricting condition; and b. means (46) connecting the second valve-actuating motor (45) with a point (39) in the supply connection (8) at which the pressure changes with the condition of the throttle valve means (35).
Claim 5
Dependent Claim
51 words
The improved hydraulic circuit defined in claim 3 in which a. the valve-actuating motors (38, 45) are connected with the same point (39) in the supply connection (8); and b. the effective area of the second valve-actuating motor (45) is smaller than the effective area of the first such motor (38).
Claim 6
Dependent Claim
121 words
The improved hydraulic circuit defined in claim 1 in which the pressure reducer (31) includes a. a regulating valve having an inlet chamber (47) connected with said point (8a) in the supply connection (8), an outlet chamber (48) connected with the pilot valve (15), and means (51, 52, 55) responsive to the pressure in the outlet chamber (48) for throttling flow from the inlet chamber to the outlet chamber as required to limit that pressure to a predetermined level; and b. a relief valve (58) interposed in a flow path (49, 56, 57, 59) interconnecting the outlet chamber (48) and the reservoir (5) and adapted to limit the pressure in the outlet chamber to a level higher than said predetermined levEl.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-12-20 | 1975-06-21 | 1975-12-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-12-20 | 1979-06-21 | 1979-12-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-12-20 | 1983-06-21 | 1983-12-21 | $7700.00 | Window Closed / Lapsed |