US3908375A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hydraulic load sensitive pressure and flow compensating system
Assignee: SPX Technologies Inc
•
Filing: 1974-09-25
•
Granted: 1975-09-30
•
Expires: 1994-09-25
Abstract
Abstract A hydraulic load sensitive pressure and flow compensating system is provided for selectively controlling operation of a plurality of hydraulic motors. The system includes a variable delivery pump having a stroke control cylinder and supplying fluid to the motors through respective motor control valves having variable restricted flow orifices. Pressure sensitive flow dividing valves connect the control valves for delivering surplus flow from one control valve to the next in order according to priority. A pressure and flow compensating valve senses a differential pressure across the last of the control valves in the order of priority and governs the delivery of the variable delivery pump by selectively alternately applying pressure to and releasing pressure from the stroke control cylinder.
Inventors
- 👤 John E G Young
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 23:14
CPC Classifications
F; F16; F16H; F16H61/00; F16H61/38; F16H61/40; F16H61/46; F15; F15B; F15B11/00; F15B11/16; F15B11/161; F15B11/162; F15B13/00; F15B13/02; F15B13/022; F15B2211/00; F15B2211/20; F15B2211/205; F15B2211/2053; F15B2211/20546; F15B2211/20553; F15B2211/255; F15B2211/30; F15B2211/305; F15B2211/30525; F15B2211/3053; F15B2211/30535; F15B2211/31; F15B2211/3105; F15B2211/3111; F15B2211/40; F15B2211/405; F15B2211/40523; F15B2211/4053; F15B2211/45; F15B2211/70; F15B2211/71; F15B2211/7142; F15B2211/78; F15B2211/781
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
125 words
A hydraulic load sensitive pressure and flow compensating sytem for selectively controlling operation of a plurality of hydraulic motors including a variable delivery pump having a stroke control cylinder and supplying fluid to the motors through respective motor control valves having variable restricting orifices wherein the improvement comprises; a. pressure sensitive flow dividing means connecting the control valves for delivering surplus flow from one control valve to the next in order according to priority, and b. pressure and flow compensating valve means sensing a differential pressure across a restricting orifice of the last of the control valves in the order of priority for governing the delivery of the variable delivery pump by selectively alternately applying pressure to and releasing pressure from the stroke control cylinder.
Claim 2
Dependent Claim
125 words
A hydraulic load sensitive pressure and flow compensating sytem for selectively controlling operation of a plurality of hydraulic motors including a variable delivery pump having a stroke control cylinder and supplying fluid to the motors through respective motor control valves having variable restricting orifices wherein the improvement comprises; a. pressure sensitive flow dividing means connecting the control valves for delivering surplus flow from one control valve to the next in order according to priority, and b. pressure and flow compensating valve means sensing a differential pressure across a restricting orifice of the last of the control valves in the order of priority for governing the delivery of the variable delivery pump by selectively alternately applying pressure to and releasing pressure from the stroke control cylinder.
Claim 3
Dependent Claim
55 words
A hydraulic load sensitive pressure and flow compensating system according to claim 1 wherein the pressure compensating valve means selectively connects the pump control cylinder alternately to an atmospheric reservoir and to an upstream passage of the last of the control valves in accordance with the differential pressure across the last of the control valves.
Claim 4
Dependent Claim
48 words
A hydraulic load sensitive pressure and flow compensating system according to claim 2 wherein the flow dividing means comprises a valve that delivers an access flow output in accordance with sensing a difference in upstream and downstream pressures across the restricting orifice of an associated motor control valve.
Claim 5
Dependent Claim
44 words
A hydraulic load sensitive pressure and flow compensating system according to claim 1 wherein pump output maximum pressure compensating valve means is provided for selectively connecting the pump control cylinder alternately to output of the pump and output to the pressure compensating control means.
Claim 6
Dependent Claim
36 words
A hydraulic load sensitive pressure and flow compensating system according to claim 4 wherein the maximum pressure compensating valve means is operable in response to an overload pressure output of the pump to destroke the pump.
Claim 7
Dependent Claim
83 words
A hydraulic load sensitive pressure and flow compensating system according to claim 1 wherein: a. a first of the control valves comprises a control valve spool for governing the motor having highest priority and a flow divider valve spool disposed in respective bores of an integral valve structure, and b. the last of the control valves comprises a control spool for governing the motor having the least priority and a pressure compensating vaLve spool disposed in respective bores of another integral valve structure.
Claim 8
Dependent Claim
34 words
A hydraulic load sensitive pressure and flow compensating system according to claim 6 wherein longitudinal movement of the compensating valve spool selectively alternately applies pressure to and releases pressure from the pump control cylinder.
Claim 9
Dependent Claim
54 words
A hydraulic load sensitive pressure and flow compensating system according to claim 7 wherein longitudinal movement of the compensating valve spool selects alternately application of fluid pressure to the pump control cylinder and release of pressure from the pump control cylinder to an atmospheric pressure reservoir in accordance with reciprocation of the compensating spool.
Claim 10
Dependent Claim
43 words
A hydraulic load sensitive pressure and flow compensating system according to claim 8 wherein means is provided for reciprocating the compensating spool by variation of the differential pressure across the restricting orifice of the control valve for the motor having the least priority.
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) | 1978-09-29 | 1979-03-31 | 1979-09-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-29 | 1983-03-31 | 1983-09-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-29 | 1987-03-31 | 1987-09-30 | $7700.00 | Window Closed / Lapsed |