US3854593A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Overload switch-off device for hydraulic lifting or adjusting mechanisms connected in tandem, in particular for hydraulic loading and unloading cranes
Assignee: Individual
•
Filing: 1972-09-19
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Granted: 1974-12-17
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Expires: 1992-09-19
Abstract
Abstract An overload switch-off device for hydraulic lifting or adjusting mechanisms connected in tandem, in particular for hydraulic loading and unloading cranes, wherein blocking valves intended for blocking the sliding spools in a main control valve block are arranged upstream of the latter. The blocking valves are capable of actuation by one or several control valves which are controlled by magnets that are actuated by means of a circuit closed by jib arm switches and an electrical pressure switch, as a result of which the flow to the hoses for the jib arms of a crane can be effected in such a way that the supply of a pressure medium (oil) to the driving elements for the lift arm, the luffing arm and the telescopic arm is interrupted if the permissible load limit is reached, while alternatively the supply for such operations is blocked which if carried out would cause further loading of the jib arms which are already loaded to their maximum permissible limit.
Inventors
- 👤 S Gross
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 23:16
CPC Classifications
F; F15; F15B; F15B13/00; F15B13/02; B; B66; B66C; B66C23/00; B66C23/88; B66C23/90; F15B20/00
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
316 words
An overload switch-off arrangement for hydraulic loading and unloading cranes comprising a plurality of jib arms connected in tandem for relative movement with respect to each other; a plurality of hydraulic actuating means, each associated with adjacent jib arms, for moving said adjacent jib arms relative to each other; a plurality of hydraulic conduit means, each connected to one of said hydraulic actuating means for conducting hydraulic fluid to and from each of said actuating means; and a plurality of main control valves, each connected to one of said hydraulic conduit means for controlling hydraulic fluid flow therethrough; said overload switch-off arrangement comprising: a. a pressure-sensitive switch in at least one of said conduit means and sensitive to a predetermined maximum hydraulic pressure, b. a plurality of switches, each associated with adjacent sets of said jib arms and arranged to be actuated when said adjacent sets of jib arms are moved to obtain a predetermined position relative to each other, c. a plurality of valve means, each associated with one of said switches, d. means operatively connecting said pressure-sensitive switch, switches and valve means, e. a plurality of hydraulically operated blocking valves, each operatively connected to one of said main control valves, and f. a plurality of further hydraulic conduit means, each extending between one of said valve means and one of said blocking valves, g. whereby an overload is detected by at least one of said valve means when actuated by closure of said pressure-sensitive switch and at least one of said switches associated with adjacent sets of said jib arms, and the associated blocking valve is actuated closing the associated main control valve, interrupting the supply of hydraulic fluid to one of said hydraulic actuating meAns, and those operations of the jib arms attending to increase the overload are blocked, while those operations of the jib arms tending to reduce the overload are permitted.
Claim 2
Dependent Claim
316 words
An overload switch-off arrangement for hydraulic loading and unloading cranes comprising a plurality of jib arms connected in tandem for relative movement with respect to each other; a plurality of hydraulic actuating means, each associated with adjacent jib arms, for moving said adjacent jib arms relative to each other; a plurality of hydraulic conduit means, each connected to one of said hydraulic actuating means for conducting hydraulic fluid to and from each of said actuating means; and a plurality of main control valves, each connected to one of said hydraulic conduit means for controlling hydraulic fluid flow therethrough; said overload switch-off arrangement comprising: a. a pressure-sensitive switch in at least one of said conduit means and sensitive to a predetermined maximum hydraulic pressure, b. a plurality of switches, each associated with adjacent sets of said jib arms and arranged to be actuated when said adjacent sets of jib arms are moved to obtain a predetermined position relative to each other, c. a plurality of valve means, each associated with one of said switches, d. means operatively connecting said pressure-sensitive switch, switches and valve means, e. a plurality of hydraulically operated blocking valves, each operatively connected to one of said main control valves, and f. a plurality of further hydraulic conduit means, each extending between one of said valve means and one of said blocking valves, g. whereby an overload is detected by at least one of said valve means when actuated by closure of said pressure-sensitive switch and at least one of said switches associated with adjacent sets of said jib arms, and the associated blocking valve is actuated closing the associated main control valve, interrupting the supply of hydraulic fluid to one of said hydraulic actuating meAns, and those operations of the jib arms attending to increase the overload are blocked, while those operations of the jib arms tending to reduce the overload are permitted.
Claim 3
Dependent Claim
129 words
An overload switch-off arrangement in accordance with claim 1 wherein said pressure-sensitive switch is an electrical pressure-sensitive switch, said switches associated with adjacent sets of said jib arms are electrical switches, said valve means associated with each switch is a solenoid-control valve means and said means connecting said pressure-sensitive switch, switches and valve means is an electrical circuit means, whereby an overload is detected by at least one of said solenoid-control valve means when actuated by closure of said electrical pressure-sensitive switch and at least one of said electrical switches associated with adjacent sets of said jib arms, and the blocking valve associated with said one solenoid-control valve is actuated closing the associated main control valve, interrupting the supply of hydraulic fluid to one of said hydraulic actuating means.
Claim 4
Dependent Claim
26 words
An overload switch-off arrangement in accordance with claim 1, wherein the blocking valves are each provided with two pistons which block the associated main control valve.
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) | 1977-12-16 | 1978-06-17 | 1978-12-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-16 | 1982-06-17 | 1982-12-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-16 | 1986-06-17 | 1986-12-17 | $7700.00 | Window Closed / Lapsed |