US3885461A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Self-locking piston and rod assembly for a fluid motor or the like
Assignee: Caterpillar Inc
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Filing: 1973-10-23
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Granted: 1975-05-27
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Expires: 1993-10-23
Abstract
Abstract The piston of a fluid operated linear motor is sealingly secured to the piston rod by means which produce a self-tightening effect in response to the rotational forces often experienced by such pistons in operation. The piston is threadably engaged on a portion of the rod and one end of the piston bites into an adjacent inclined step thereon to provide a seal between the piston and the rod. A lock nut bearing against the piston is threadably engaged on an adjacent portion of the rod which has threads with a finer pitch. Owing to the differences in the threads rotational forces, which might otherwise tend to loosen the piston and seal, have the effect of jamming the piston more tightly against the lock nut.
Inventors
- 👤 Chester A Crisp
- 👤 Herschel M Williamson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 02:11
CPC Classifications
F; F16; F16B; F16B39/00; F16B39/02; F16B39/12; F16B39/16; F16J; F16J1/00; F16J1/10; F16J1/12; F16B2200/00; F16B2200/40; F16B2200/403
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
222 words
A piston and piston rod assembly for reciprocation within a cylinder comprising a piston rod having a first portion with threads thereon of a first pitch and having a second portion with threads thereon of a lesser pitch, an annular piston threadably engaged on said first portion of said rod, the threaded engagement of said piston on said rod being wholly at said first portion thereof, a lock nut threadably engaged on said second portion of said rod and in direct engagement with said piston for exerting axial pressure on said piston, said second portion of said rod being of reduced diameter relative to said first portion thereof and said lock nut has an internal diameter correspondingly smaller than that of said piston, a conical step being formed on said rod adjacent said first portion thereof, and said piston has a threaded bore through which said first portion of said rod extends, said bore having theads engaging said threads of said first portion of said rod with the end of said bore adjacent said step being unthreaded and forming with a planar face of said piston a continuous annular sharp edge which bites into said concial step of said rod upon threading of said piston on said first portion of said rod to block fluid flow between said piston and said rod.
Claim 2
Dependent Claim
222 words
A piston and piston rod assembly for reciprocation within a cylinder comprising a piston rod having a first portion with threads thereon of a first pitch and having a second portion with threads thereon of a lesser pitch, an annular piston threadably engaged on said first portion of said rod, the threaded engagement of said piston on said rod being wholly at said first portion thereof, a lock nut threadably engaged on said second portion of said rod and in direct engagement with said piston for exerting axial pressure on said piston, said second portion of said rod being of reduced diameter relative to said first portion thereof and said lock nut has an internal diameter correspondingly smaller than that of said piston, a conical step being formed on said rod adjacent said first portion thereof, and said piston has a threaded bore through which said first portion of said rod extends, said bore having theads engaging said threads of said first portion of said rod with the end of said bore adjacent said step being unthreaded and forming with a planar face of said piston a continuous annular sharp edge which bites into said concial step of said rod upon threading of said piston on said first portion of said rod to block fluid flow between said piston and said rod.
References Cited (Backward Citations)
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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) | 1978-05-26 | 1978-11-25 | 1979-05-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-05-26 | 1982-11-25 | 1983-05-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-05-26 | 1986-11-25 | 1987-05-27 | $7700.00 | Window Closed / Lapsed |