US3873240A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hydraulic swash plate pump
Assignee: Individual
•
Filing: 1973-06-15
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Granted: 1975-03-25
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Expires: 1993-06-15
Abstract
Abstract Swash plate pump comprising a rotatable swash plate the inclination of which is controlled by a hydraulic jack means. The jack means is in turn controlled by a slide valve which detects the variations in the delivery pressures of the pump and causes a high or a low pressure to actuate the jack means, whereby the inclination of the swash plate is modified and consequently the output of the pump varied. The slide valve is further acted upon by a spring.
Inventors
- 👤 Gerard Leduc
- 👤 Michel Leduc
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 21:41
CPC Classifications
F; F04; F04B; F04B1/00; F04B1/12; F04B1/14; F04B1/18; F04B1/26; F04B1/28; F04B1/29; F04B1/295; F04B49/00; F04B49/08
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
207 words
In a hydraulic swash plate pump whose driving torque is to be kept constant as a function of delivery pressure, said pump comprising: a rotatable swash plate mounted for variable inclination, means driving said swash plate for establishing a pump delivery pressure, a hydraulic jack means for varying the inclination of said swash plate, control means having first and second inlets and an outlet, means for providing fluid at the delivery pressure to said first inlet and means for providing low pressure fluid to said second inlet, means including a chamber in fluid communication with said jack and responsive to an applied fluid to move said control means, means communicating between said control valve means outlet and said jack moving means, said control valve means moving in response to variation of pressure in said chamber and communicating the fluid from one of said first or second inlets to said outlet to move said jack in a direction to change the inclination of the swash plate to maintain a given torque at said driving means in response to a variable delivery pressure, said control valve means also being movable with respect to said jack to vary the flow of the fluid to said jack as the jack moves.
Claim 2
Dependent Claim
207 words
In a hydraulic swash plate pump whose driving torque is to be kept constant as a function of delivery pressure, said pump comprising: a rotatable swash plate mounted for variable inclination, means driving said swash plate for establishing a pump delivery pressure, a hydraulic jack means for varying the inclination of said swash plate, control means having first and second inlets and an outlet, means for providing fluid at the delivery pressure to said first inlet and means for providing low pressure fluid to said second inlet, means including a chamber in fluid communication with said jack and responsive to an applied fluid to move said control means, means communicating between said control valve means outlet and said jack moving means, said control valve means moving in response to variation of pressure in said chamber and communicating the fluid from one of said first or second inlets to said outlet to move said jack in a direction to change the inclination of the swash plate to maintain a given torque at said driving means in response to a variable delivery pressure, said control valve means also being movable with respect to said jack to vary the flow of the fluid to said jack as the jack moves.
Claim 3
Dependent Claim
26 words
A pump as in claim 1 wherein said jack moving means includes restricted passage means (24a, 25-24a, 25) for supplying the fluid to said chamber (26-26).
Claim 4
Dependent Claim
52 words
A pump as in claim 1 wherein said control means includes a slide valve communicating with and responsive to the pressure in said chamber (26-26) and further comprising spring means for exerting a force on said slide valve means in opposition to the force exerted thereon by the fluid in said chamber.
Claim 5
Dependent Claim
21 words
Pump according to claim 3 wherein said spring has a predetermined rigidity curve corresponding to desired variations in deliveries and pressures.
Claim 6
Dependent Claim
16 words
Pump according to claim 1 wherein said control means comprises a valve located inside the jack.
Claim 7
Dependent Claim
118 words
Pump according to claim 3 wherein the jack includes a piston having a surface communicAting with said chamber, said piston of the jack controlling the swash plate having a double section of different sizes, said jack moving means including two chambers situated so that one communicates with the large section and the other communicates with the small section of said jack piston, a calibrated passage means providing communication between said two chambers, the chamber situated behind the large section receiving either the high pressure or the low pressure by means of the valve, so that, with equilibrium, the said valve being closed, these two chambers are at the same pressure, which is a function of the delivery pressure.
Claim 8
Dependent Claim
53 words
Pump according to claim 6, wherein the slide member of the valve projects into the chamber which communicates with the small section of the jack and is subjected to the pressure obtaining in this chamber, so that any variation of the delivery pressures causes a displacement of the slide member of the valve.
Claim 9
Dependent Claim
29 words
Pump according to claim 7, further comprising a fixed stop against which said spring bears said fixed stop comprising a partition separating the two chambers situated behind the jack.
Claim 10
Dependent Claim
42 words
Pump according to claim 7, further comprising a fixed stop against which said spring bears said fixed stop comprising a partition separating the two chambers situated behind the control jack of the swash plate, and second spring means bearing on the jack.
Claim 11
Dependent Claim
42 words
Pump according to claim 6, further comprising a partition separating said two chambers and wherein said calibrated passage is formed by an annular space provided between the small-section of the jack and an orifice formed in the partition separating the said chambers.
Claim 12
Dependent Claim
29 words
Pump according to claim 10, wherein the jack includes a rod having a shoulder extending through said orifice such that the said annular calibrated passage is of variable length.
Claim 13
Dependent Claim
89 words
Pump according to claim 3 wherein the pump includes pumping pistons having bearing studs thereon, said swash plate being formed with a plurality of passages on the path of the bearing studs of the pumping pistons in a path corresponding to their delivery travel, a central chamber formed at the back of the swash plate with which said passages communicate, said jack having a piston including a supporting stud for providing communication between said central chamber and a passage formed in the said piston and ending at the valve.
Claim 14
Dependent Claim
47 words
Pump according to claim 1 wherein said pump includes delivery pistons and further comprising means for selecting the highest delivery pressure including an assembly of interconnected passages equipped with non-return valves, said passages being located in the casing of the pump body downstream of the delivery pistons.
Claim 15
Dependent Claim
42 words
Pump according to claim 13, further comprising additional non-return valves at the outlet of each delivery pistons, said non-return selection valves being located downstream of said additional non-return valves which are located at the outlet of the bore of each delivery piston.
Claim 16
Dependent Claim
31 words
Pump according to claim 13, further comprising additional non-return valves at the outlet of each of said delivery pistons, said selection non-return valves being positioned upstream of the additional non-return valves.
Claim 17
Dependent Claim
18 words
Pump according to claim 13 further comprising selection non-return valves for all the delivery systems of the pump.
Claim 18
Dependent Claim
16 words
Pump according to claim 13 wherein said selection non-return valve provides a single delivery by flow.
Claim 19
Dependent Claim
46 words
Pump according to claim 1, further comprising first means for applying the highest selected delivery pressure to the valve positioned inside the jack by means, said first means comprising a passage drilled in the casing of the pump body and a passage drilled in the jack.
Claim 20
Dependent Claim
43 words
Pump according to claim 18, further comprising a joint between two passages, said joint including a ring which is centered with friction on the jack and is held immobile to rotation, said ring having a passage providing communication between the said two passages.
Claim 21
Dependent Claim
43 words
Pump according to claim 12 wherein the high pressure selected at the passage ending at the valve communicates with a further passage connecting two passage assemblies supplying the said high pressure to the bearings of the said shaft in two diametrically opposite zones.
Claim 22
Dependent Claim
18 words
Pump according to claim 14 further comprising selection non-return valves for all the delivery systems of the pump.
Claim 23
Dependent Claim
18 words
Pump according to claim 14 further comprising a selection non-return valves for providing a single delivery by flow.
Claim 24
Dependent Claim
37 words
Pump according to claim 13 wherein means for selecting the high pressure communicates with a passage connecting two passage assemblies supplying the said high pressure to the bearings of the said shaft in two diametrically opposite zones.
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 |