US3758079A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Control system for balancing hoist
Assignee: Gardner Denver Inc
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Filing: 1970-11-18
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Granted: 1973-09-11
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Expires: 1990-11-18
Abstract
Abstract A control system for a pneumatically operated balancing hoist in which a load attached to the hoist cable is balanced by regulating air pressure acting on the piston of an expansible chamber hoist motor. The control system is characterized by a pneumatic control circuit including a pressure regulating valve which has a sensor operable to sense the pressure in the hoist motor chamber required to balance a load and set the regulator valve to maintain the load balancing pressure value. The control circuit also includes a pneumatically operated valve which limits the flow of compressed air to the hoist motor to prevent rapid wind-up of the hoist cable. A further feature of the control system includes a circuit arrangement in which the hoist motor exhaust valve is operable to exhaust pressure air from the motor chamber only in response to receiving a positive pressure signal from a pendant hoist controller.
Inventors
- 👤 W Workman
- 👤 G Pontiac
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 01:21
CPC Classifications
B; B66; B66D; B66D3/00; B66D3/18; B66D2700/00; B66D2700/02; B66D2700/026
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
235 words
A control system for a fluid operated balancing hoist, said balancing hoist including a pressure fluid operated motor having an expansible chamber, means connected to said motor and operable to be connected to a load for raising and balancing said load in response to the operation of said motor, and passage means for conducting pressure fluid to and from said expansible chamber; said control system including a pressure fluid regulator valve connected to said passage means for supplying pressure fluid to said expansible chamber, said regulator valve including pressure sensing means having a movable actuator in communication with said expansible chamber for sensing the pressure in said expansible chamber and for causing said regulator valve to change said fluid pressure in response to a change in the weight of said load, means for locking said actuator including means for gripping and holding said actuator in a predetermined position for causing said regulator valve to maintain a fluid pressure in said expansible chamber corresponding to a balanced condition of a load connected to said hoist, said means for locking said actuator including fluid operated release means for releasing said actuator to move to cause said regulator valve to change said fluid pressure in response to a change in the weight of said load; and, said control system includes a controller including valve means for supplying pressure fluid for operating said release means to release said actuator.
Claim 2
Dependent Claim
235 words
A control system for a fluid operated balancing hoist, said balancing hoist including a pressure fluid operated motor having an expansible chamber, means connected to said motor and operable to be connected to a load for raising and balancing said load in response to the operation of said motor, and passage means for conducting pressure fluid to and from said expansible chamber; said control system including a pressure fluid regulator valve connected to said passage means for supplying pressure fluid to said expansible chamber, said regulator valve including pressure sensing means having a movable actuator in communication with said expansible chamber for sensing the pressure in said expansible chamber and for causing said regulator valve to change said fluid pressure in response to a change in the weight of said load, means for locking said actuator including means for gripping and holding said actuator in a predetermined position for causing said regulator valve to maintain a fluid pressure in said expansible chamber corresponding to a balanced condition of a load connected to said hoist, said means for locking said actuator including fluid operated release means for releasing said actuator to move to cause said regulator valve to change said fluid pressure in response to a change in the weight of said load; and, said control system includes a controller including valve means for supplying pressure fluid for operating said release means to release said actuator.
Claim 3
Dependent Claim
51 words
The invention set forth in claim 1 wherein: said controller includes valve means including actuating means for supplying pressure fluid to said expansible chamber, and said actuating means is operable to actuate said release valve means to release said actuator concurrently with the supplying of pressure fluid to said expansible chamber.
Claim 4
Dependent Claim
51 words
The invention set forth in claim 2 wherein: said control system includes exhaust valve means connected to said expansible chamber, and said exhaust valve means includes a pressure fluid actuator responsive to pressure fluid being supplied thereto for operating said exhaust valve means to vent pressure fluid from said expansible chamber.
Claim 5
Dependent Claim
28 words
The invention set forth in claim 3 wherein: said controller includes valve means for supplying pressure fluid to said pressure fluid actuator to actuate said exhaust valve means.
Claim 6
Dependent Claim
165 words
A control system for a fluid operated balancing hoist, said balancing hoist including a pressure fluid operated motor having an expansible chamber, means connected to said motor and operable to be connected to a load for raising and balancing said load in response to the operation of said motor, and passage means for conducting pressure fluid to said expansible chamber; said control system including valve means in communication with said passage means for valving pressure fluid to said motor from a pressure fluid supply for raising a load, and flow control means interposed in said passage means between said pressure fluid supply and said motor and including means responsive to a low pressure condition in said expansible chamber for causing said flow control means to limit the flow pressure fluid to said expansible chamber, said means being responsive to an increased pressure condition in said expansible chamber for causing said flow control means to provide substantially unrestricted flow of pressure fluid to said expansible chamber.
Claim 7
Dependent Claim
165 words
A control system for a fluid operated balancing hoist, said balancing hoist including a pressure fluid operated motor having an expansible chamber, means connected to said motor and operable to be connected to a load for raising and balancing said load in response to the operation of said motor, and passage means for conducting pressure fluid to said expansible chamber; said control system including valve means in communication with said passage means for valving pressure fluid to said motor from a pressure fluid supply for raising a load, and flow control means interposed in said passage means between said pressure fluid supply and said motor and including means responsive to a low pressure condition in said expansible chamber for causing said flow control means to limit the flow pressure fluid to said expansible chamber, said means being responsive to an increased pressure condition in said expansible chamber for causing said flow control means to provide substantially unrestricted flow of pressure fluid to said expansible chamber.
Claim 8
Dependent Claim
78 words
The invention set forth in claim 5 wherein: said flow control means comprises valve means movable to be in a first position to limit the flow of pressure fluid to said expansible chamber and a second position to provide substantially unrestricted flow of pressure fluid to said expansible chamber, and said means responsive to said increased pressure condition in said expansible chamber includes actuator means for moving said valve means from said first position to said second position.
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) | 1976-09-10 | 1977-03-12 | 1977-09-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-09-10 | 1981-03-12 | 1981-09-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-09-10 | 1985-03-12 | 1985-09-11 | $7700.00 | Window Closed / Lapsed |