US3783748A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Cam follower piston
Assignee: National Research Development Corp UK
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Filing: 1971-09-02
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Granted: 1974-01-08
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Expires: 1991-09-02
Abstract
Abstract A piston adapted to carry a cam follower and particularly for use as a ball or roller piston in a hydrostatic pump or motor, comprises a piston body having a seating at one end, an insert of low friction material which is shaped to provide in the seating a bearing for the cam follower, and means for securing the insert to the piston body. The piston body preferably has a recess or aperture communicating with the seating and the insert of low friction material extends into or through the recess or aperture to lock the insert to the piston body. The insert is conveniently made of polytetrafluorethylene, nylon or an acetal material.
Inventors
- 👤 S Cunningham
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 10:18
CPC Classifications
F; F16; F16J; F16J1/00; F16J1/10; F16J1/14; F16J1/22; F01; F01B; F01B3/00; F01B3/0082; F01B3/0085; F04; F04B; F04B1/00; F04B1/12; F04B1/122; F04B1/124; F05; F05C; F05C2225/00; F05C2225/04
Claims Analysis
Total Claims: 1
Claim 1
Independent Claim
195 words
A piston for a hydrostatic machine comprising: a freely rotating cam follower member for following a cam surface in a hydrostatic machine by reciprocatory motion of the cam follower member in a cylinder bore of the machine; a piston body for reciprocatory travel along the cylinder bore, said piston body having at one end a working face for exposure to the working fluid of said hydrostatic machine, and at the other end a seating face defining a seating for said cam follower member but exposing a portion of said cam follower member protruding from said piston body to engage a cam surface, said piston body having at least one aperture extending from said seating to a side wall of said piston body; an insert of low friction synthetic plastics material positioned between said cam follower member and said seating in said piston body and having an internal bearing surface for said cam follower member, said insert extending through said at least one side wall aperture and forming around the perimeter of said side wall a sealing ring adapted to engage the inner surface of said cylinder bore within which said piston body reciprocates in use.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-01-07 | 1977-07-09 | 1978-01-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-01-07 | 1981-07-09 | 1982-01-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-01-07 | 1985-07-09 | 1986-01-08 | $7700.00 | Window Closed / Lapsed |