US3807175A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fluid system having positive vertical hold means
Assignee: Individual
•
Filing: 1972-06-06
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Granted: 1974-04-30
•
Expires: 1992-06-06
Abstract
Abstract A fluid system having a variable displacement fluid pump connected in a closed-loop fashion to a fluid cylinder having a piston and a pair of connecting rods extending from opposite sides of the piston and externally of the fluid cylinder with one rod supporting a vertically displacable load. A directional flow control valve connected to the inlet and outlet of the fluid pump selectively directs fluid to pressure chambers within the fluid cylinder on opposite sides of the piston to reciprocate the same within the fluid cylinder and displace the load. The lower pressure chamber of the fluid cylinder, which is exhausted during a downward stroke of the piston, is in communication with the pump via the directional flow control valve and a pilot operated check valve which, in its normally closed position, permits fluid flow from the pump outlet through the directional flow control valve to the lower pressure chamber while preventing fluid flow from the lower pressure chamber to the pump inlet and thereby maintaining the load at any desired vertical position. An independent source of fluid, maintained at a constant pressure, is selectively connected to the pilot operated check valve to open same to permit an unrestricted communication between the lower pressure chamber of the fluid cylinder and the directional flow control valve when the same is shifted to communicate high pressure fluid from the pump outlet to the upper pressure chamber of the fluid cylinder to move the load downwardly.
Inventors
- 👤 P Kubik
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 13:42
CPC Classifications
F; F15; F15B; F15B13/00; F15B13/01; F15B11/00; F15B11/02; F15B2211/00; F15B2211/20; F15B2211/205; F15B2211/2053; F15B2211/20546; F15B2211/20553; F15B2211/30; F15B2211/305; F15B2211/30505; F15B2211/30525; F15B2211/315; F15B2211/3157; F15B2211/31576; F15B2211/32; F15B2211/327; F15B2211/329; F15B2211/355; F15B2211/50; F15B2211/505; F15B2211/50509; F15B2211/50518; F15B2211/515; F15B2211/5158; F15B2211/5159; F15B2211/55; F15B2211/60; F15B2211/615; F15B2211/635; F15B2211/6355; F15B2211/70; F15B2211/705; F15B2211/7051; F15B2211/7053; F15B2211/7054
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
205 words
A fluid system comprising: a fluid pump having inlet and outlet means; a fluid cylinder having reciprocating piston means and first and second port means respectively communicating within said fluid cylinder on the opposite sides of said piston means; directional flow control valve means selectively operable to connect said pump inlet and outlet means to said first and second port means, in a closed loop fashion for reciprocating said piston means within said cylinder; pilot operated check valve means disposed between said directional flow control valve means and one of said cylinder port means, said check valve means being normally operable to permit fluid flow from said directional flow control valve means to said one port means and prevent a reverse flow of fluid from said one port means to said directional flow control valve means; an independent source of fluid pressure; control valve means operable upon actuation for communicating said independent source of fluid pressure to said pilot operated check valve to open same and permit fluid flow from said one port means to said directional flow control valve means; and means for actuating said control valve means when said directional control valve means communicates said pump outlet to said other cylinder port means.
Claim 2
Dependent Claim
205 words
A fluid system comprising: a fluid pump having inlet and outlet means; a fluid cylinder having reciprocating piston means and first and second port means respectively communicating within said fluid cylinder on the opposite sides of said piston means; directional flow control valve means selectively operable to connect said pump inlet and outlet means to said first and second port means, in a closed loop fashion for reciprocating said piston means within said cylinder; pilot operated check valve means disposed between said directional flow control valve means and one of said cylinder port means, said check valve means being normally operable to permit fluid flow from said directional flow control valve means to said one port means and prevent a reverse flow of fluid from said one port means to said directional flow control valve means; an independent source of fluid pressure; control valve means operable upon actuation for communicating said independent source of fluid pressure to said pilot operated check valve to open same and permit fluid flow from said one port means to said directional flow control valve means; and means for actuating said control valve means when said directional control valve means communicates said pump outlet to said other cylinder port means.
Claim 3
Dependent Claim
52 words
The fluid system defined in claim 1, wherein said fluid pump is a variable displacement pump; and further comprising pressure responsive means for varying displacement of said pump; said independent source of pressure being adapted to be selectively communicated to said pressure responsive means for varying displacement of said variable displacement pump.
Claim 4
Dependent Claim
84 words
The fluid system defined in claim 2, wherein said directional flow control valve means comprises a pilot operated directional flow control valve having a first spool means movable when pressure is selectively communicated to the opposite ends thereof, and a pilot valve having a spool means for selectively communicating said control pressure to the opposite sides of said first mentioned spool means, said pilot valve spool being adapted to communicate said control pressure to said pilot operated check valve when in a selected position.
Claim 5
Dependent Claim
127 words
The fluid system defined in claim 1, wherein said pilot operated check valve comprises a passageway having a valve seat and a valve member engagable thereto, said valve member being movable in one direction to permit flow thereacross, said valve member having rod means extending therefrom and engaging a piston member, said piston member being exposable to said control pressure and adapted to cause said valve member to unseat from said valve seat or permit fluid communication in an opposite direction through said check valve, the effective pressure responsive area of said piston member of said pilot operated valve tending to open said pilot operated valve being 40 times greater than the effective pressure responsive area of said valve member tending to close said pilot operated valve.
Claim 6
Dependent Claim
181 words
A fluid system comprising: a fluid pump having inlet and outlet means; a fluid cylinder having reciprocating piston means and first and second port means respectively communicating within said fluid cylinder on the opposite sides of said piston means; means selectively operable to connect said pump inlet and outlet means to said first and second port means, in a closed loop fashion for reciprocating said piston means within said cylinder; pilot operated check valve means disposed between said pump and one of said cylinder port means, said check valve means being normally operable to permit fluid flow from said pump to said one port means and prevent a reverse flow of fluid from said one port means to said pump; an independent source of fluid pressure; control valve means opeRable upon actuation for communicating said independent source of fluid pressure to said pilot operated check valve to open same and permit fluid flow from said one port means to said pump; and means for actuating said control valve means when said pump outlet is communicated to said other cylinder port means.
Claim 7
Dependent Claim
181 words
A fluid system comprising: a fluid pump having inlet and outlet means; a fluid cylinder having reciprocating piston means and first and second port means respectively communicating within said fluid cylinder on the opposite sides of said piston means; means selectively operable to connect said pump inlet and outlet means to said first and second port means, in a closed loop fashion for reciprocating said piston means within said cylinder; pilot operated check valve means disposed between said pump and one of said cylinder port means, said check valve means being normally operable to permit fluid flow from said pump to said one port means and prevent a reverse flow of fluid from said one port means to said pump; an independent source of fluid pressure; control valve means opeRable upon actuation for communicating said independent source of fluid pressure to said pilot operated check valve to open same and permit fluid flow from said one port means to said pump; and means for actuating said control valve means when said pump outlet is communicated to said other cylinder port means.
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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) | 1977-04-29 | 1977-10-29 | 1978-04-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-04-29 | 1981-10-29 | 1982-04-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-04-29 | 1985-10-29 | 1986-04-30 | $7700.00 | Window Closed / Lapsed |