Patent US3894476A successfully refreshed from Google Patents.
US3894476A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Self-adjusting load balancing pneumatic hoist
Assignee: United States Department of Energy
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Filing: 1974-04-05
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Granted: 1975-07-15
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Expires: 1994-04-05
Abstract
Abstract The present invention is directed to a pneumatic hoist incorporating a load balancing system whereby a load supported by the hoist may be vertically repositioned by applying a relatively small force against the load in the direction of desired movement. The load balancing system utilizes a pressure regulator which is capable of continuously maintaining the pressure in the hoist to equal a reference pressure automatically established as required to balance the load and sealed in a pilot chamber of the regulator to provide for the vertical displacement of the load in response to a relatively small force applied in the direction of the desired movement.
Inventors
- 👤 William G Cobb
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 23:14
CPC Classifications
B; B66; B66C; B66C13/00; B66C13/04
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
236 words
A pneumatic hoist positionable between a load and load lifting mechanism for automatically maintaining the load in a selected vertical position provided upon displacing the load by exerting an externally applied force thereon and for significantly reducing the force required to effect the displacement of the load, comprising a cylinder and piston assembly with said cylinder connectable to one of said load and said lifting mechanism and said piston connectable to the other of said one of said load and said lifting mechanism, a housing, movable piston means disposed in said housing for dividing the latter into first and second chambers, a passageway in said piston means communicating with said first chamber and atmosphere, conduit means in registry with both of said chambers and further chamber on one side of said piston in said cylinder, valve means in said conduit means for selectively placing either the first or second chamber in communication with said cylinder, a further conduit means in registry with said first chamber for introducing a flow of pressurized air thereinto from a compressed air supply, and further valve means in said first chamber for regulating the flow of said air through said passageway to atmosphere and into said first chamber from said further conduit means in response to the direction of movement of said piston means with said movement being responsive to the pressure differential in said first chamber and said second chamber.
Claim 2
Dependent Claim
236 words
A pneumatic hoist positionable between a load and load lifting mechanism for automatically maintaining the load in a selected vertical position provided upon displacing the load by exerting an externally applied force thereon and for significantly reducing the force required to effect the displacement of the load, comprising a cylinder and piston assembly with said cylinder connectable to one of said load and said lifting mechanism and said piston connectable to the other of said one of said load and said lifting mechanism, a housing, movable piston means disposed in said housing for dividing the latter into first and second chambers, a passageway in said piston means communicating with said first chamber and atmosphere, conduit means in registry with both of said chambers and further chamber on one side of said piston in said cylinder, valve means in said conduit means for selectively placing either the first or second chamber in communication with said cylinder, a further conduit means in registry with said first chamber for introducing a flow of pressurized air thereinto from a compressed air supply, and further valve means in said first chamber for regulating the flow of said air through said passageway to atmosphere and into said first chamber from said further conduit means in response to the direction of movement of said piston means with said movement being responsive to the pressure differential in said first chamber and said second chamber.
Claim 3
Dependent Claim
78 words
The pneumatic hoist claimed in claim 1, wherein an additional conduit means connects said further chamber and said compressed air supply, additional valve means are in said additional conduit means for placing said further chamber in registry with said compressed air supply for introducing compressed air into said further chamber, and wherein the first mentioned valve means places said second chamber in registry with said compressed air supply through said additional conduit means simultaneously with said further chamber.
Claim 4
Dependent Claim
60 words
The pneumatic hoist claimed in claim 2 wherein a still further conduit means connects said further chamber and said compressed air supply, and wherein valve means are disposed in said still further conduit means contiguous to said further chamber and contactable by said piston for effecting flow of compressed air through said still further conduit means into said further chamber.
Claim 5
Dependent Claim
24 words
The pneumatic hoist claimed in claim 1 wherein valve means are in registry with said second chamber for discharging compressed air therein to atmosphere.
Claim 6
Dependent Claim
112 words
The pneumatic hoist claimed in claim 1 wherein said further valve means comprises a first ball engageable with the passageway in said piston means, a second ball engageable with said further conduit means, a rod interconnecting said balls, and bias means urging both of said first ball and said second ball into an air flow inhibiting engagement with said passageway and said further conduit means, and wherein said piston operates said further valve means to selectively establish communication between said first chamber and atmosphere and said first chamber and said compressed air supply when the pressure in said first chamber is respectively greater and less than the pressure in said second chamber.
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) | 1978-07-14 | 1979-01-13 | 1979-07-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-07-14 | 1983-01-13 | 1983-07-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-07-14 | 1987-01-13 | 1987-07-15 | $7700.00 | Window Closed / Lapsed |