Patent US4088151A successfully refreshed from Google Patents.
US4088151A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Cylinder locking apparatus
Assignee: Borg Warner Corp
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Filing: 1976-05-26
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Granted: 1978-05-09
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Expires: 1996-05-26
Abstract
Abstract A cylinder locking apparatus primarily intended for use on counter-balanced lift trucks incorporating lift cylinders of the single-acting type, comprising a positive sealing poppet-type check valve which operates in the normal manner when the system is in the raise mode, but which in the lowering mode is operable by controlled pilot means triggered manually by the system's main control valve spool, thus permitting the load to be lowered by gravity.
Inventors
- 👤 Joseph A. Schurger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 17:11
CPC Classifications
F; F15; F15B; F15B13/00; F15B13/01; B; B66; B66F; B66F9/00; B66F9/06; B66F9/075; B66F9/20; B66F9/22; F15B13/015; Y; Y10; Y10T; Y10T137/00; Y10T137/8593; Y10T137/87169; Y10T137/87233; Y10T137/87241
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
267 words
A flow control mechanism comprising a body defining a bore and an inlet, an outlet, and a first passage communicating with said bore, said body further defining a chamber communicating with said first passage, a second passage communicating said chamber with said bore, and a work port, said mechanism further comprising a spool slidable in said bore between a first position establishing fluid communication between said inlet and said first passage through said bore and a second position establishing fluid communication between said first passage and said outlet through said bore, said spool defining a third passage communicating said bore with said outlet, a check valve, said check valve having a check valve element movable between an open position establishing fluid communication between said first passage and said work port and a closed position blocking fluid communication therebetween, said check valve defining flow restricting means communicating said chamber with said work port, said check valve element being biased by fluid pressure in said chamber for movement toward its closed position, and a pilot valve, said pilot valve having a pilot valve seat in said bore, and a pilot valve element slidable in said bore between a seated position isolating said second passage from said third passage and an unseated position establishing fluid communication between said second passage and said outlet through said third passage, said pilot valve element being biased by fluid pressure in said second passage for movement toward its seated position, said pilot valve element being engageable and movable by said spool toward its unseated position upon movement of said spool toward its second position.
Claim 2
Dependent Claim
267 words
A flow control mechanism comprising a body defining a bore and an inlet, an outlet, and a first passage communicating with said bore, said body further defining a chamber communicating with said first passage, a second passage communicating said chamber with said bore, and a work port, said mechanism further comprising a spool slidable in said bore between a first position establishing fluid communication between said inlet and said first passage through said bore and a second position establishing fluid communication between said first passage and said outlet through said bore, said spool defining a third passage communicating said bore with said outlet, a check valve, said check valve having a check valve element movable between an open position establishing fluid communication between said first passage and said work port and a closed position blocking fluid communication therebetween, said check valve defining flow restricting means communicating said chamber with said work port, said check valve element being biased by fluid pressure in said chamber for movement toward its closed position, and a pilot valve, said pilot valve having a pilot valve seat in said bore, and a pilot valve element slidable in said bore between a seated position isolating said second passage from said third passage and an unseated position establishing fluid communication between said second passage and said outlet through said third passage, said pilot valve element being biased by fluid pressure in said second passage for movement toward its seated position, said pilot valve element being engageable and movable by said spool toward its unseated position upon movement of said spool toward its second position.
Claim 3
Dependent Claim
51 words
The invention of claim 1, said check and pilot valves having resilient means biasing said check and pilot valve elements toward their closed and seated positions respectively, said pilot valve being of the differential area type such that minimal bias is developed by fluid pressure in said second passage acting thereon.
Claim 4
Dependent Claim
45 words
The invention of claim 1, said body having first and second body portions, said first portion defining said inlet, said outlet, said first passage and said work port, said second portion defining said second passage, and said portions together defining said bore and said chamber.
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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) | 1981-05-08 | 1981-11-07 | 1982-05-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-05-08 | 1985-11-07 | 1986-05-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-05-08 | 1989-11-07 | 1990-05-09 | $7700.00 | Window Closed / Lapsed |