Patent US2331559A successfully refreshed from Google Patents.
Patent US3784328A successfully refreshed from Google Patents.
US3784328A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Power transmission
Assignee: Vickers Inc
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Filing: 1972-06-13
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Granted: 1974-01-08
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Expires: 1992-06-13
Abstract
Abstract A pressure regulated variable delivery hydraulic pump includes a control for varying the pump displacement which responds not only to outlet pressure of the pump, but also to the rate of change of pressure and to the rate of change of pump delivery. Regulation is by outlet pressure opposed by two springs in back-to-back relation with a dashpot intermediate the two springs which retards rapid movements of one spring in backing up the other. The dashpot action is further modified by a feedback responsive to the rate of change of pump displacement. The result is a servocontrol system which has high gain characteristics for small transients and lower gain for large transients and an increased damping ratio with a reduction in overshoots of pressure transients.
Inventors
- 👤 N Pedersen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 20:48
CPC Classifications
F; F04; F04B; F04B49/00; F04B49/08; F04B1/00; F04B1/12; F04B1/26; F04B1/30; F04B1/32; F04B1/324
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
110 words
In a pressure regulated variable delivery pump having an inlet and an outlet, expansible chamber means for pumping fluid therebetween, a shiftable member connected with the expansible chamber means and effective to vary the volumetric pumping capacity, and hydraulic regulating means including a slidable fluid displacement device connected to outlet pressure for shifting the member, that improvement which comprises a multiple spring system opposing outlet pressure at the regulating means, including a first spring acting directly on the regulating means, a second spring backing up the first spring, a dashpot means intermediate the two springs effective to retard rapid movements of the second spring in backing up the first spring.
Claim 2
Dependent Claim
110 words
In a pressure regulated variable delivery pump having an inlet and an outlet, expansible chamber means for pumping fluid therebetween, a shiftable member connected with the expansible chamber means and effective to vary the volumetric pumping capacity, and hydraulic regulating means including a slidable fluid displacement device connected to outlet pressure for shifting the member, that improvement which comprises a multiple spring system opposing outlet pressure at the regulating means, including a first spring acting directly on the regulating means, a second spring backing up the first spring, a dashpot means intermediate the two springs effective to retard rapid movements of the second spring in backing up the first spring.
Claim 3
Dependent Claim
30 words
A pump as defined in claim 1 wherein the regulating means includes a servopiston and a pilot valve for selectively connecting the servopiston to either the inlet or the outlet.
Claim 4
Dependent Claim
45 words
A pump as defined in claim 1 wherein the dashpot means includes a first chamber surrounding the first spring and connected to the inlet, a second chamber surrounding the second spring, a floating piston separating the chambers and a restricted connection between the two chambers.
Claim 5
Dependent Claim
46 words
A pump as defined in claim 1 having a feedback means operated by the shiftable member and connected to the dash-pot means for modifying the back-up action of the second spring on the first spring in accordance with the rate of movement of the shiftable member.
Claim 6
Dependent Claim
30 words
A pump as defined in claim 3 having a feedback means operated by the shiftable member including a piston connected to displace fluid into or out of the second chamber.
Claim 7
Dependent Claim
30 words
A pump as defined in claim 5 wherein the regulating means includes a servopiston and a pilot valve for selectively connecting the servopiston to either the inlet or the outlet.
Claim 8
Dependent Claim
17 words
A pump as defined in claim 1 wherein the first and second springs have equal force-displacement rates.
Claim 9
Dependent Claim
17 words
A pump as defined in claim 4 wherein the first and second springs have equal force-displacement rates.
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) | 1977-01-07 | 1977-07-09 | 1978-01-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-01-07 | 1981-07-09 | 1982-01-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-01-07 | 1985-07-09 | 1986-01-08 | $7700.00 | Window Closed / Lapsed |