US3874173A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hydrostatic power transmission system
Assignee: Individual
•
Filing: 1973-06-04
•
Granted: 1975-04-01
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Expires: 1993-06-04
Abstract
Abstract A hydrostatic power transmission system with co-ordinated control of prime mover and pump, supplying any number of rotary and linear hydrostatic motors controlled integrally and by power transformers respectively.
Inventors
- 👤 Bernard Charles Wilkins
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 15:55
CPC Classifications
F; F16; F16H; F16H61/00; F16H61/38; F16H61/40; F16H61/4148; F16H61/4078; F16H61/4096; F16H61/44; F16H61/456; F16H61/46; F16H61/42; F16H61/423
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
82 words
A hydrostatic power transmission system comprising in combination a reservoir containing liquid at low pressure, a prime-mover-driven pump controlled to deliver the liquid from the reservoir at sensibly constant higher pressure, a plurality of independent rotary variable-displacement hydrostatic motors controlled by integral feedback mechanisms, any number of independent linear hydrostatic motors controlled by power transformers, interconnected high-pressure conduits connecting said pump to said motors and said power transformers, and interconnected low-pressure conduits connecting said motors and said power transformers to said reservoir.
Claim 2
Dependent Claim
82 words
A hydrostatic power transmission system comprising in combination a reservoir containing liquid at low pressure, a prime-mover-driven pump controlled to deliver the liquid from the reservoir at sensibly constant higher pressure, a plurality of independent rotary variable-displacement hydrostatic motors controlled by integral feedback mechanisms, any number of independent linear hydrostatic motors controlled by power transformers, interconnected high-pressure conduits connecting said pump to said motors and said power transformers, and interconnected low-pressure conduits connecting said motors and said power transformers to said reservoir.
Claim 3
Dependent Claim
50 words
The hydrostatic power transmission system as defined in claim 1, in which the prime-mover-driven pump is characterised by an expanding gas cylinder, a common piston member, and a hydraulic cylinder, so combined that the linear motion of the prime mover is transmitted directly to the liquid in the hydraulic cylinder.
Claim 4
Dependent Claim
46 words
The hydrostatic power transmission system as defined in claim 1, in which a pressure-sensing servo system acts upon the pump and the prime mover to start and stop motion of the prime mover and to vary prime mover speed and pump Displacement in any desired relationship.
Claim 5
Dependent Claim
93 words
The hydrostatic power transmission system as defined in claim 1, in which at least one hydrostatic power transformer comprises in combination a pair of variable-displacement hydrostatic pump/motor units, each with two liquid ports and one shaft, so arranged that one port of one pump/motor unit is connected to a higher pressure conduit, and one port of the other pump/motor unit is connected to a lower pressure conduit, the two remaining ports connected to an output pressure conduit, and the shafts mechanically coupled, with the displacement controls automatically actuated to control pressure and flow.
Claim 6
Dependent Claim
33 words
The hydrostatic power transmission system as defined in claim 4, in which at least one linear hydrostatic motor is supplied with power in any required form by one of the hydrostatic power transformers.
Claim 7
Dependent Claim
45 words
The hydrostatic power transmission system as defined in claim 1, in which at least one variable-displacement hydrostatic motor incorporates pressure-sensing servo means for varying motor displacement, so as to maintain a sensibly constant pressure drop across a constriction in an individual conduit of the motor.
Claim 8
Dependent Claim
40 words
The hydrostatic power transmission system as defined in claim 6, in which the constriction is variable in area and coupled to the motor displacement control, so that the displacement of the motor is proportional to the area of the constriction.
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) | 1978-03-31 | 1978-09-30 | 1979-04-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-31 | 1982-09-30 | 1983-04-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-31 | 1986-09-30 | 1987-04-01 | $7700.00 | Window Closed / Lapsed |