US3792747A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Pressure-compensated hand pump
Assignee: Enerpac Tool Group Corp
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Filing: 1971-12-21
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Granted: 1974-02-19
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Expires: 1991-12-21
Abstract
Abstract A hand pump having compensating means thereon for optimizing displacement per stroke while the force required to operate the pump is maintained at a relatively constant level over a widely variable load pressure range.
Inventors
- 👤 D Knutson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 11:54
CPC Classifications
F; F04; F04B; F04B49/00; F04B49/12; B; B62; B62D; B62D33/00; B62D33/06; B62D33/063; B62D33/067; B62D33/07; F04B9/00; F04B9/14
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
249 words
In a vehicle comprising a frame, a cab tiltably mounted on said frame, a hydraulic cylinder assembly attached at one end to said frame and at the other end to said cab, said cylinder being double acting and having first and second chambers, a hand pump, said pump comprising a housing having inlet and outlet means, conduit means communicating said inlet and outlet means to said first and second chambers, a reservoir in communication with said inlet means, a pumping chamber in said housing in communication with said outlet means, a pumping piston slidably received in said pumping chamber, a handle attached to said pumping piston at a point spaced from one end of said handle, said housing having a compensating chamber disposed transversely relative to said first chamber, a second piston slidably received in said compensating chamber, said handle being pivotally attached at said one end to said second piston, a load pressure sensing passageway communicating waid compensating chamber to said outlet means whereby said second piston is shifted in response to pressure changes in said outlet means to vary the effective length of said handle between said connection point with said pumping piston and said pivotal connection with said second piston, valve means in said housing for selectively communicating said first and second chambers with said pumping chamber and said reservoir through said conduit means, and metering means in said valve means for metering the outflow from that chamber of said cylinder assembly communicated to said reservoir.
Claim 2
Dependent Claim
249 words
In a vehicle comprising a frame, a cab tiltably mounted on said frame, a hydraulic cylinder assembly attached at one end to said frame and at the other end to said cab, said cylinder being double acting and having first and second chambers, a hand pump, said pump comprising a housing having inlet and outlet means, conduit means communicating said inlet and outlet means to said first and second chambers, a reservoir in communication with said inlet means, a pumping chamber in said housing in communication with said outlet means, a pumping piston slidably received in said pumping chamber, a handle attached to said pumping piston at a point spaced from one end of said handle, said housing having a compensating chamber disposed transversely relative to said first chamber, a second piston slidably received in said compensating chamber, said handle being pivotally attached at said one end to said second piston, a load pressure sensing passageway communicating waid compensating chamber to said outlet means whereby said second piston is shifted in response to pressure changes in said outlet means to vary the effective length of said handle between said connection point with said pumping piston and said pivotal connection with said second piston, valve means in said housing for selectively communicating said first and second chambers with said pumping chamber and said reservoir through said conduit means, and metering means in said valve means for metering the outflow from that chamber of said cylinder assembly communicated to said reservoir.
Claim 3
Dependent Claim
214 words
A hand pump for actuating a double-acting cylinder having first and second chambers comprising a housing having inlet and outlet means, conduit means communicating said inlet and outlet means to said first and second chambers, a reservoir in communication with said inlet means, a pumping chamber in said housing in communication with said outlet means, a pumping piston slidably received in said pumping chamber, a handle attached to said pumping piston at a point spaced from one end of said handle, said housing having a compensating chamber disposed transversely relative to said first chamber, a second piston slidably received in said compensating chamber, said handle being pivotally attached at said one end to said second piston, a load pressure sensing passageway communicating said compensating chamber to said outlet means whereby said second piston is shifted in response to pressure changes in said outlet means to vary the effective length of said handle between said connection point with said pumping piston and said pivotal connection with said second piston, valve means in said housing for selectively communicating said first and second chambers with said pumping chamber and said reservoir through said conduit means, and metering means in said valve means for metering the outflow from that chamber of said cylinder assembly communicated to said reservoir.
Claim 4
Dependent Claim
214 words
A hand pump for actuating a double-acting cylinder having first and second chambers comprising a housing having inlet and outlet means, conduit means communicating said inlet and outlet means to said first and second chambers, a reservoir in communication with said inlet means, a pumping chamber in said housing in communication with said outlet means, a pumping piston slidably received in said pumping chamber, a handle attached to said pumping piston at a point spaced from one end of said handle, said housing having a compensating chamber disposed transversely relative to said first chamber, a second piston slidably received in said compensating chamber, said handle being pivotally attached at said one end to said second piston, a load pressure sensing passageway communicating said compensating chamber to said outlet means whereby said second piston is shifted in response to pressure changes in said outlet means to vary the effective length of said handle between said connection point with said pumping piston and said pivotal connection with said second piston, valve means in said housing for selectively communicating said first and second chambers with said pumping chamber and said reservoir through said conduit means, and metering means in said valve means for metering the outflow from that chamber of said cylinder assembly communicated to said reservoir.
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) | 1977-02-18 | 1977-08-20 | 1978-02-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-02-18 | 1981-08-20 | 1982-02-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-02-18 | 1985-08-20 | 1986-02-19 | $7700.00 | Window Closed / Lapsed |