US3650108A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hydrostatic transmission control
Assignee: Sigma
•
Filing: 1969-09-17
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Granted: 1972-03-21
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Expires: 1989-09-17
Abstract
Abstract A hydrostatic transmission of the kind useful in an automotive vehicle is controlled automatically by adjustment of the output of a driven hydraulic generator (i.e., a pump) to maintain the torque absorbed by the generator substantially equal to the vehicle driving motor torque. Such adjustment is effected in accordance with fluid pressure established in accordance with the generator speed but modified in accordance with fluid pressure established between the generator and a receptor (i.e., a hydraulic motor) connected hydraulically thereto and connectable mechanically to one or more traction wheels of the vehicle.
Inventors
- 👤 Olivier Isaac
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 09:55
CPC Classifications
F; F16; F16H; F16H61/00; F16H61/38; F16H61/40; F16H61/46; F16H61/472; Y; Y10; Y10S; Y10S60/00; Y10S60/906
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
191 words
In a hydrostatic transmission, a device for controlling the stroke volume of a variable stroke hydraulic pump, supplying a hydraulic motor through a closed circuit, said device comprising: an auxiliary constant stroke pump to replenish the closed circuit with liquid, an adjustable choke member, mounted in a hydraulic circuit traversed by a flow of liquid dependent on the rotary speed of the variable stroke pump, adapted to create a loss of load, a first hydraulic jack sensitive to said load loss, adapted to control the stroke volume of the variable stroke pump, a second hydraulic jack sensitive to the delivery pressure of the variable stroke pump, adapted to control the opening of said choke member so that, when the delivery pressure of the variable stroke pump increases, a reduction in the stroke volume of the latter is effected, and a tachometric constant stroke pump, distinct from said auxiliary pump, driven at a speed proportional to that of the constant stroke pump, said tachometric pump feeding in parallel, the adjustable choke member and the first hydraulic jack, said choke member being connected, downstream, to a reservoir of liquid at relatively nil pressure.
Claim 2
Dependent Claim
191 words
In a hydrostatic transmission, a device for controlling the stroke volume of a variable stroke hydraulic pump, supplying a hydraulic motor through a closed circuit, said device comprising: an auxiliary constant stroke pump to replenish the closed circuit with liquid, an adjustable choke member, mounted in a hydraulic circuit traversed by a flow of liquid dependent on the rotary speed of the variable stroke pump, adapted to create a loss of load, a first hydraulic jack sensitive to said load loss, adapted to control the stroke volume of the variable stroke pump, a second hydraulic jack sensitive to the delivery pressure of the variable stroke pump, adapted to control the opening of said choke member so that, when the delivery pressure of the variable stroke pump increases, a reduction in the stroke volume of the latter is effected, and a tachometric constant stroke pump, distinct from said auxiliary pump, driven at a speed proportional to that of the constant stroke pump, said tachometric pump feeding in parallel, the adjustable choke member and the first hydraulic jack, said choke member being connected, downstream, to a reservoir of liquid at relatively nil pressure.
Claim 3
Dependent Claim
100 words
Device according to claim 1 comprising a slide valve having an output connected by a supply channel to the second hydraulic jack, said slide valve having means selective as to direction of operation and having two inputs, each of said input being connected to a respective side of said closed hydraulic circuit, the means selective of the direction of operation of said slide valve being adapted to occupy the position for which the supply channel of said second hydraulic jack is connected to that side of the closed circuit where the delivery pressure of the variable stroke pump is exerted.
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) | 1975-03-21 | 1975-09-20 | 1976-03-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-03-21 | 1979-09-20 | 1980-03-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-03-21 | 1983-09-20 | 1984-03-21 | $7700.00 | Window Closed / Lapsed |