US4016719A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hydrostatic transmission system
Assignee: Technion Research and Development Foundation Ltd
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Filing: 1976-03-30
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Granted: 1977-04-12
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Expires: 1996-03-30
Abstract
Abstract An hydraulic power transmission circuit comprises a high-pressure section and a low-pressure section, which together include (a) an internal or external combustion free-piston engine to each of whose pistons is attached one piston pump, the pump piston and the engine piston being rigidly connected for the purpose of joint axial motion; (b) at least one rotary motor or linear actuator adapted to be driven by the hydraulic fluid pressurized by the said piston pumps; (c) valve means for directing the hydraulic fluid to and from the motors or actuators; (d) a charge pump; (e) accumulator means for balancing the fluctuations of pressure and quantity of the hydraulic fluid; and (f) means for controlling the operation of the free-piston engine, said means comprising a rotary auxiliary hydraulic motor of the positive displacement type in the low-pressure section of the circuit, which motor is provided with transmission means for driving a rotary distributor at a number of revolutions governed by the frequency of the free-piston engine.
Inventors
- 👤 Amotz Yavnai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 18:28
CPC Classifications
F; F16; F16H; F16H43/00; F02; F02B; F02B71/00; F02B71/04; F02B71/045; F02G; F02G1/00; F02G1/04; F02G1/043; F02G1/0435; F02B75/00; F02B75/02; F02B2075/022; F02B2075/025
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
220 words
A hydrostatic transmission system comprising a hydraulic circuit consisting of a high-pressure section and a low-pressure section, which together include a free-piston engine having at least two cylinders each having one engine piston to which is connected a pump piston, said engine piston being rigidly connected to said pump piston for the purpose of joint axial motion; at least one rotary motor or linear actuator adapted to be driven by the hydraulic fluid pressurized by said piston pumps; valve means for directing the hydraulic fluid to and from said motor or actuator; means for controlling the operation of said free-piston engine, said controlling means comprising a rotary distributor and a rotary, auxiliary hydraulic motor of the positive displacement type in the low-pressure section of the circuit, said auxiliary hydraulic motor being provided with transmission means for driving said rotary distributor at the number of revolutions governed by the frequency of said free-piston engine, said rotary distributor being provided with ports for alternately connecting each pump cylinder in turn to the high-pressure section and to the low-pressure section of the hydraulic circuit in such an order that each pump is connected to the high-pressure section during at least part of its pumping stroke from the stroke's beginning, and to the low pressure section during the entire length of its return stroke.
Claim 2
Dependent Claim
220 words
A hydrostatic transmission system comprising a hydraulic circuit consisting of a high-pressure section and a low-pressure section, which together include a free-piston engine having at least two cylinders each having one engine piston to which is connected a pump piston, said engine piston being rigidly connected to said pump piston for the purpose of joint axial motion; at least one rotary motor or linear actuator adapted to be driven by the hydraulic fluid pressurized by said piston pumps; valve means for directing the hydraulic fluid to and from said motor or actuator; means for controlling the operation of said free-piston engine, said controlling means comprising a rotary distributor and a rotary, auxiliary hydraulic motor of the positive displacement type in the low-pressure section of the circuit, said auxiliary hydraulic motor being provided with transmission means for driving said rotary distributor at the number of revolutions governed by the frequency of said free-piston engine, said rotary distributor being provided with ports for alternately connecting each pump cylinder in turn to the high-pressure section and to the low-pressure section of the hydraulic circuit in such an order that each pump is connected to the high-pressure section during at least part of its pumping stroke from the stroke's beginning, and to the low pressure section during the entire length of its return stroke.
Claim 3
Dependent Claim
42 words
A hydrostatic transmission system as claimed in claim 1, wherein said auxiliary motor is so dimensioned as to rotate at a speed proportional to the engine frequency while receiving the entire quantity of fluid returned to the pumps, through the low-pressure section.
Claim 4
Dependent Claim
49 words
A hydrostatic transmission system as claimed in claim 1, wherein said auxiliary motor is also adapted to drive auxiliary equipment such as a fuel injection pump or a spark-ignition mechanism, at a speed suitable for timing their operation with the speed of the prime engine piston to be served.
Claim 5
Dependent Claim
60 words
A hydraulic transmission system as claimed in claim 1 wherein the high-pressure section and the low-pressure section are connected to form a closed circuit arranged for the entire quantity of the hydraulic fluid to pass through the high-pressure section to the drive motors or actuator and then through the low-pressure section and said auxiliary motor back to the pump cylinders.
Claim 6
Dependent Claim
107 words
A hydraulic transmission system as claimed in claim 1 wherein the high-pressure section and the low-pressure section form an open circuit, wherein the distributor ports are adapted to deliver hydraulic fluid to the drive motor or actuator only during the first part of the expansion stroke of the free-piston engine, and to the auxiliary motor during the second part of the expansion stroke, while duct means are provided for guiding the fluid discharged from the drive motor or actuator into an open sump, a charge pump to be driven by the auxiliary motor being provided to deliver the hydraulic fluid from said pump to the auxiliary motor.
Claim 7
Dependent Claim
36 words
A system in accordance with claim 1 further comprising accumulator means for balancing the fluctuations of pressure and quantity of the hydraulic fluid, said accumulator means being located between said controlling means and said valve means.
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) | 1980-04-11 | 1980-10-11 | 1981-04-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-04-11 | 1984-10-11 | 1985-04-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-04-11 | 1988-10-11 | 1989-04-12 | $7700.00 | Window Closed / Lapsed |