US3744379A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Rotary hydraulic machines
Assignee: ZF International UK Ltd
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Filing: 1971-03-29
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Granted: 1973-07-10
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Expires: 1991-03-29
Abstract
Abstract A hydraulic pump or motor in which a rotor has a plurality of pistons slidable in radial bores in the rotor. The pistons engage a cam ring surrounding the rotor, and the eccentricity of the cam ring can be varied by means of one or more servo pistons.
Inventors
- 👤 F Freeman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 22:38
CPC Classifications
F; F01; F01B; F01B13/00; F01B13/04; F01B13/06; F01B13/061; F04; F04B; F04B49/00; F04B49/12; F04B49/123; F04B49/128; F04B1/00; F04B1/04; F04B1/06; F04B1/07
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
119 words
A rotary hydraulic manhine comprising a casing, a pintle secured to and extending into the casing, a rotor rotatable about the pintle, a plurality of radial bores in the rotor, pistons reciprocable respectively in the bores, a cam ring within the casing surrounding the rotor and pistons, the pistons engaging the inner face of the cam ring and means for varying the eccentricity of the cam ring with respect to the rotor, said eccentricity varying means including a bore within the pintle, a piston responsive to a servo pressure slidable within the pintle bore and being cooperable with the cam ring to urge the cam ring in one direction to vary the eccentricity thereof with respect to the rotor.
Claim 2
Dependent Claim
119 words
A rotary hydraulic manhine comprising a casing, a pintle secured to and extending into the casing, a rotor rotatable about the pintle, a plurality of radial bores in the rotor, pistons reciprocable respectively in the bores, a cam ring within the casing surrounding the rotor and pistons, the pistons engaging the inner face of the cam ring and means for varying the eccentricity of the cam ring with respect to the rotor, said eccentricity varying means including a bore within the pintle, a piston responsive to a servo pressure slidable within the pintle bore and being cooperable with the cam ring to urge the cam ring in one direction to vary the eccentricity thereof with respect to the rotor.
Claim 3
Dependent Claim
15 words
The machine as claimed in claim 1 in which said servo piston is a ball.
Claim 4
Dependent Claim
55 words
The machine as claimed in claim 1 including a further servo-piston slidable in a further bore in the pintle, said further servo-piston being responsive to a further servo, pressure and coacting with said cam ring to urge the cam ring in a direction opposite to its movement in response to the first mentioned servo pressure.
Claim 5
Dependent Claim
24 words
The machine as claimed in claim 3 which includes biasing means acting on said further servo piston in support of said further servo pressure.
Claim 6
Dependent Claim
15 words
The machine as claimed in claim 3 in which said further piston is a ball.
Claim 7
Dependent Claim
30 words
The machine as claimed in claim 1 including a projection extending internally of said casing, about which projection said cam can roll under the influence of said servo responsive piston.
Claim 8
Dependent Claim
23 words
The machine as claimed in claim 1 in which each said piston in said radial bores includes a slipper engaging said cam ring.
Claim 9
Dependent Claim
18 words
The machine as claimed in claim 7 in which said slippers are secured to said pistons by studs.
Claim 10
Dependent Claim
19 words
The machine as claimed in claim 1 including a sealing arrangement on said casing through which said rotor extends.
Claim 11
Dependent Claim
36 words
The machine as claimed in claim 9 in which said sealing arrangement comprises a pair of rings mounted on the casing and sealingly engaging said rotor, and means biasing said rings into engagement with said rotor.
Claim 12
Dependent Claim
19 words
The machine as claimed in claim 10 in which said rings define a chamber which communicates with a drain.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-07-09 | 1977-01-08 | 1977-07-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-09 | 1981-01-08 | 1981-07-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-09 | 1985-01-08 | 1985-07-10 | $7700.00 | Window Closed / Lapsed |