US3742820A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Power transmission
Assignee: Vickers Inc
•
Filing: 1971-09-22
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Granted: 1973-07-03
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Expires: 1991-09-22
Abstract
Abstract A displacement adjusting system for a variable displacement pump which delivers in a single direction only utilizes a pair of laminar flow restrictions connected in series in a bleed circuit and operated mechanically by the displacement regulator of the pump to increase one restriction as the other is decreased in proportion to changes in pump displacement. The pressure level at the point between the two restrictors is applied against a variable spring bias on a pilot valve to control a servomotor acting on the pump displacement regulator. The control maintains a maximum on pump input torque under all load variations and this limit is adjustable through the pilot valve spring.
Inventors
- 👤 K Lonnemo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 08:23
CPC Classifications
F; F04; F04B; F04B49/00; F04B49/08; F04B49/002
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
160 words
A displacement adjusting system for a one-way variable displacement pump having an inlet and an outlet, comprising a member shiftable to change the pump displacement, hydraulic servomotor means to shift the member, means forming a bleed circuit from the outlet to the inlet, a pair of mutually and oppositely adjustable flow restrictions in series in the bleed circuit, means connecting the restrictions to the shiftable member to vary them equally and oppositely in proportion to the movements of the shiftable member, a pilot valve controlling the servomotor, a pilot valve operator connected to respond to the pressure level at the point in the bleed circuit between the two restrictions, and an adjustable resilient biasing means opposing the pilot valve operator, whereby the displacement of the pump will be varied automatically as its loading changes so as to maintain a limit on the torque required to drive the pump which limit is determined by the setting of the adjustable biasing means.
Claim 2
Dependent Claim
160 words
A displacement adjusting system for a one-way variable displacement pump having an inlet and an outlet, comprising a member shiftable to change the pump displacement, hydraulic servomotor means to shift the member, means forming a bleed circuit from the outlet to the inlet, a pair of mutually and oppositely adjustable flow restrictions in series in the bleed circuit, means connecting the restrictions to the shiftable member to vary them equally and oppositely in proportion to the movements of the shiftable member, a pilot valve controlling the servomotor, a pilot valve operator connected to respond to the pressure level at the point in the bleed circuit between the two restrictions, and an adjustable resilient biasing means opposing the pilot valve operator, whereby the displacement of the pump will be varied automatically as its loading changes so as to maintain a limit on the torque required to drive the pump which limit is determined by the setting of the adjustable biasing means.
Claim 3
Dependent Claim
16 words
A system as defined in claim 1 wherein the flow restrictions have a common movable member.
Claim 4
Dependent Claim
16 words
A system as defined in claim 1 wherein the flow restrictions are of the laminar type.
References Cited (Backward Citations)
US3165068A
Cited
US3296797A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-07-02 | 1977-01-01 | 1977-07-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-02 | 1981-01-01 | 1981-07-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-02 | 1985-01-01 | 1985-07-03 | $7700.00 | Window Closed / Lapsed |