Patent US3817152A successfully refreshed from Google Patents.
US3817152A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hydraulic jack
Assignee: Individual
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Filing: 1972-03-13
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Granted: 1974-06-18
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Expires: 1992-03-13
Abstract
Abstract Fluid pressure system comprises a piston which is slidably mounted in a cylinder and divides said cylinder into two variable chambers, said chambers being interconnected through a by-pass, and said piston having two main surfaces, each exposed to the pressure in one of said variable chambers, and a third surface exposed to the pressure in a space other than one of said chambers, and means responsive to a predetermined increase in the pressure in said space to connect one of said chambers to a source of fluid pressure, to close said by-pass, and to connect the other of said chambers to exhaust.
Inventors
- 👤 M Viron
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 19:55
CPC Classifications
B; B29; B29C; B29C45/00; B29C45/17; B29C45/64; B29C45/67; B29C45/6764; F; F15; F15B; F15B15/00; F15B15/20; F15B15/204
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
199 words
Fluid pressure system comprising a piston member (10) which is slidably mounted in a cylinder (12) and divides said cylinder into two variable volume chambers (14, 15), said chambers being connected through a by-pass (17), and said piston member having two main surfaces (10a, 10b), having substantially identical areas each exposed to the pressure in one of said variable-volume chambers, and a third surface (10c) exposed to the pressure in a first space (9) other than either of said chambers, and means (6, 7, 8) for actuating said piston member, said actuating means comprising means for connecting said space to a source of pressure fluid (4) thus applying pressure to said third surface (10c) to advance said piston member in one direction while driving fluid from one of said chambers (14) to the other (15) through said by-pass until the advance of said piston produces a predetermined effect, and means (22, 20, 23) responsive to the attainment of said predetermined effect for automatically increasing the pressure on said piston member by connecting said other chamber to a source of fluid under pressure, closing said by-pass, and connecting said one chamber (14) to exhaust when said predetermined effect is attained.
Claim 2
Dependent Claim
199 words
Fluid pressure system comprising a piston member (10) which is slidably mounted in a cylinder (12) and divides said cylinder into two variable volume chambers (14, 15), said chambers being connected through a by-pass (17), and said piston member having two main surfaces (10a, 10b), having substantially identical areas each exposed to the pressure in one of said variable-volume chambers, and a third surface (10c) exposed to the pressure in a first space (9) other than either of said chambers, and means (6, 7, 8) for actuating said piston member, said actuating means comprising means for connecting said space to a source of pressure fluid (4) thus applying pressure to said third surface (10c) to advance said piston member in one direction while driving fluid from one of said chambers (14) to the other (15) through said by-pass until the advance of said piston produces a predetermined effect, and means (22, 20, 23) responsive to the attainment of said predetermined effect for automatically increasing the pressure on said piston member by connecting said other chamber to a source of fluid under pressure, closing said by-pass, and connecting said one chamber (14) to exhaust when said predetermined effect is attained.
Claim 3
Dependent Claim
152 words
A fluid pressure system as claimed in claim 1 in which said piston member has a fourth surface (10d) facing in a direction opposite to that faced by said third surface (10c) and subject to the pressure in a second space (26) outside said cylinder, said actuating means comprises a first reversible pressure fluid distributor (8) movable between a first position connecting said first space (9) to said pressure source and said second space (26) to exhaust, and said pressure increasing means comprises a second, reversible electrically actuated fluid distributor (38) movable between a first position connecting said one chamber (14) to said pressure source (4) and said other chamber (15) to exhaust, a second position in which neither chamber is connected to said pressure source (4) and a third position in which said other chamber (15) is connected to said pressure source and said one chamber (14) is connected to exhaust.
Claim 4
Dependent Claim
25 words
A fluid pressure system as claimed in claim 6 comprising electrical means for actuating said second distributor and responsive to the position of said rod.
Claim 5
Dependent Claim
39 words
A fluid pressure system as claimed in claim 3 in which said electrical means for actuating said second distributor is also responsive to the position of a device to which the pressure on said piston is to be applied.
Claim 6
Dependent Claim
31 words
Fluid pressure system as claimed in claim 1 in which said piston member is connected to a rod which actuates apparatus offering a varying resistance to the movement of said piston.
Claim 7
Dependent Claim
22 words
Fluid pressure system as claimed in claim 5 in which pressure increasing means is responsive to the pressure in said first space.
Claim 8
Dependent Claim
75 words
Fluid pressure system as claimed in claim 1 in which said means for connecting one of said chambers to a source of fluid pressure and for closing said by-pass is a single spring-loaded valve responsive to the pressure in said space, and movable between a first position in which it closes a connection between said other chamber and said pressure source and a second position in which it closes said by-pass but opens said connection.
Claim 9
Dependent Claim
129 words
A fluid pressure system as claimed in claim 1 in which said piston member has a fourth surface facing in a direction opposite to that faced by said third surface and subject to the pressure in a second space outside said cylinder, and said actuating means comprises reversible pressure fluid distributor means movable between a first position in which it is connected upon operation of said pressure increasing means to simultaneously supply pressure fluid to one of said spaces and one of said variable chambers while connecting the other of said spaces and the other of said variable chambers to exhaust, and a second position in which pressure fluid is supplied to said other space and variable chamber while said one space and variable chamber are connected to exhaust.
Claim 10
Dependent Claim
76 words
A fluid pressure system as claimed in claim 8 in which said pressure increasing means comprises two spring-loaded valves in said by-pass, one of which is responsive to the pressure in each of said spaces, and each of which is movable between a first position in which it closes a connection between a different one of said chambers and said pressure source and a second position in which it closes said by-pass but opens said connection.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-06-17 | 1977-12-17 | 1978-06-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-17 | 1981-12-17 | 1982-06-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-17 | 1985-12-17 | 1986-06-18 | $7700.00 | Window Closed / Lapsed |