Patent US1070729A successfully refreshed from Google Patents.
Patent US3575534A successfully refreshed from Google Patents.
US3575534A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Constant torque hydraulic pump
Assignee: Individual
•
Filing: 1969-02-05
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Granted: 1971-04-20
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Expires: 1989-02-05
Abstract
Abstract A constant torque hydraulic pump having a swashplate of variable inclination pivotally mounted on a support and rotatable about a predetermined axis. The hydraulic control piston is mounted within the support for modifying the inclination of the swashplate, and a regulating valve is in fluid communication with an outlet orifice of the pump and is coaxially located with respect to the axis. A calibrated orifice assembly is located adjacent to the swashplate, and a spring bearing is located between the regulating valve and the calibrated orifice assembly for enabling inclination of the swashplate in accordance with the pressure at the outlet orifice to maintain a substantially constant driving torque for the pump.
Inventors
- 👤 Gerard Leduc
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 16:00
CPC Classifications
F; F04; F04B; F04B1/00; F04B1/12; F04B1/26; F04B1/28; F04B1/29; F04B1/295; F04B1/14; F04B49/00; F04B49/08; F16; F16H; F16H23/00; F16H23/02
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
158 words
A hydraulic pump comprising: a housing assembly having input and output orifices; a support rotatable about a predetermined axis; a swashplate of variable inclination pivotally mounted on said support and rotatable about said predetermined axis; a hydraulic control piston mounted within the support for modifying the inclination of said swashplate; a regulating valve in fluid communication with said outlet orifice and coaxially located with respect to said axis; said fluid communication enabling movement of said regulating valve in a direction along said predetermined axis; a calibrated orifice assembly located in adjacent relationship with said swashplate; a spring bearing located between said regulating valve and said calibrated orifice assembly for enabling inclination of said swashplate in accordance with the pressure at said outlet orifice to maintain a substantially constant driving torque for said pump; and said calibrated orifice assembly cooperating with said spring bearing to determine forces acting against said regulating valve in a direction along said predetermined axis.
Claim 2
Dependent Claim
158 words
A hydraulic pump comprising: a housing assembly having input and output orifices; a support rotatable about a predetermined axis; a swashplate of variable inclination pivotally mounted on said support and rotatable about said predetermined axis; a hydraulic control piston mounted within the support for modifying the inclination of said swashplate; a regulating valve in fluid communication with said outlet orifice and coaxially located with respect to said axis; said fluid communication enabling movement of said regulating valve in a direction along said predetermined axis; a calibrated orifice assembly located in adjacent relationship with said swashplate; a spring bearing located between said regulating valve and said calibrated orifice assembly for enabling inclination of said swashplate in accordance with the pressure at said outlet orifice to maintain a substantially constant driving torque for said pump; and said calibrated orifice assembly cooperating with said spring bearing to determine forces acting against said regulating valve in a direction along said predetermined axis.
Claim 3
Dependent Claim
65 words
A pump as in claim 1 wherein said regulating valve receives on one of its faces the outlet pressure of said pump and on another face the combined action of said spring bearing and an intermediate hydraulic pressure inferior to said outlet pressure and which is a function of said outlet pressure and of the hydraulic flow going to or coming from said control piston.
Claim 4
Dependent Claim
75 words
A hydraulic pump according to claim 2 in which said intermediate pressure prevails in an intermediate chamber communicating with the control piston acting on the plate by way of a calibrated opening in said orifice assembly and in such a way that the pressure obtained in the chamber is a function of the speed of displacement of the said control piston, said pressure thus having a corrective action on the displacement of said regulating valve.
Claim 5
Dependent Claim
44 words
A hydraulic pump according to claim 2 for use with a reservoir tank in which said regulating valve comprises a valve member which causes said intermediate chamber to communicate either with the outlet pressure or with the tank, depending on its direction of movement.
Claim 6
Dependent Claim
23 words
A hydraulic pump according to claim 2 in which said spring bearing acting upon said regulating valve is located within said intermediate chamber.
Claim 7
Dependent Claim
19 words
A hydraulic pump according to claim 2 in which said spring bearing is a spring having a variable resiliency.
Claim 8
Dependent Claim
46 words
A hydraulic pump according to claim 6 in which the resilient characteristics of said spring bearing are determined so that a distinct angle Alpha of the plate with said axis corresponds to each outlet pressure P, and thus the driving torque of the pump remains constant.
Claim 9
Dependent Claim
42 words
A hydraulic pump according to claim 2 further including an odd number of first pistons located to successively subject the swashplate to the action of a variable number of said first pistons to cause a pressure pulsation which suppresses the friction threshold.
Claim 10
Dependent Claim
86 words
A hydraulic pump according to claim 8 comprising: a calibrated spring and a safety valve having a valve member held in a neutral position by said calibrated spring, said valve member causing said intermediate chamber to communicate with the outlet of one of said first pistons of the pump when the pressure exceeds a predetermined valve, so thaT as soon as this pressure is reached, the control piston of the swashplate acts on this latter in order to bring the said angle Alpha back to zero.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-04-19 | 1974-10-19 | 1975-04-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-04-19 | 1978-10-19 | 1979-04-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-04-19 | 1982-10-19 | 1983-04-20 | $7700.00 | Window Closed / Lapsed |