Patent US3872957A successfully refreshed from Google Patents.
US3872957A
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US
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Fluid-supply system for hydraulic coupling
Assignee: ZF Friedrichshafen AG
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Filing: 1973-11-28
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Granted: 1975-03-25
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Expires: 1993-11-28
Abstract
Abstract A hydraulically actuated coupling (i.e. a clutch or a brake), designed to control the transmission of torque from an engine to a load, receives operating fluid from an engine-driven oil pump via a supply line in which, with engine speeds above a certain limit, a substantially constant oil pressure is maintained by a spring-biased pressure-relief valve provided with an overflow line carrying a flow of excess oil under variable pressure. The overflow line, from which an extension leads to engine bearings and other units to be lubricated and/or cooled, and a branch of the supply line extend through constrictions to a conduit for the circulation of a mixture of constant-pressure and variablepressure oil as a lubricating and/or cooling liquid through the hydraulic coupling.
Inventors
- 👤 Gerhard Maurer
- 👤 Fritz Geiger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 05:15
CPC Classifications
F; F16; F16D; F16D25/00; F16D25/12; F16D25/123
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
151 words
A fluid-supply system for a hydraulically actuated coupling controlling the transmission of torque from an engine to a load, said coupling being provided with a first inlet for a working fluid and with a second inlet for an ancillary fluid, comprising: an engine-driven pump for the circulation of a hydraulic liquid; a supply line extending from said pump to said first inlet; pressure-regulating means connected to said supply line for maintaining therein a fluid pressure substantially independent of engine speed with the engine operating above a predetermined speed limit; an overflow line for excess fluid under variable pressure connected to said pressure-regulating means; a branch line connected to said supply line; and a conduit communicating with said overflow line and with said branch line for delivering a mixture of fluid of variable pressure from said overflow line and fluid of substantially constant pressure from said branch line to said second inlet.
Claim 2
Dependent Claim
151 words
A fluid-supply system for a hydraulically actuated coupling controlling the transmission of torque from an engine to a load, said coupling being provided with a first inlet for a working fluid and with a second inlet for an ancillary fluid, comprising: an engine-driven pump for the circulation of a hydraulic liquid; a supply line extending from said pump to said first inlet; pressure-regulating means connected to said supply line for maintaining therein a fluid pressure substantially independent of engine speed with the engine operating above a predetermined speed limit; an overflow line for excess fluid under variable pressure connected to said pressure-regulating means; a branch line connected to said supply line; and a conduit communicating with said overflow line and with said branch line for delivering a mixture of fluid of variable pressure from said overflow line and fluid of substantially constant pressure from said branch line to said second inlet.
Claim 3
Dependent Claim
25 words
A fluid-supply system as defined in claim 1 wherein said overflow line and said branch line are provided with respective constrictions upstream of said conduit.
Claim 4
Dependent Claim
32 words
A fluid-supply system as defined in claim 2 wherein said overflow line is provided with an extension, upstream of said constriction thereof, for the delivery of excess hydraulic liquid to another load.
Claim 5
Dependent Claim
26 words
A fluid-supply system as defined in claim 1 wherein said pressure-regulating means comprises a spring-loaded pressure-relief valve having a control inlet connected to said supply line.
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) | 1978-03-24 | 1978-09-23 | 1979-03-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-24 | 1982-09-23 | 1983-03-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-24 | 1986-09-23 | 1987-03-25 | $7700.00 | Window Closed / Lapsed |