A double-acting threaded jack includes an outer cylinder having a liquid guiding hole, an inner piston rod installed at the center of the outer cylinder, a lifting piston rod sheathed on the inner piston rod, and a pressure relief module installed in the outer cylinder; a liquid guiding pipeline passing through the inner piston rod; and first and second hydraulic chambers formed between the lifting piston rod and the inner piston rod. A liquid is filled from the liquid guiding pipeline into the first/second hydraulic chamber to descend/ascend the lifting piston rod respectively. The pressure relief module has an adjusting member with a through hole, a stop member for stopping the liquid guiding pipeline, and a spring installed between the adjusting member and the stop member. The liquid will push open the stop member and discharge from the through hole of the adjusting member in an overpressure situation.
ANTI-OVERPRESSURE DOUBLE-ACTING THREADED JACK
2015-07-30
Patent
Elektronische Ressource
Englisch
IPC: | B66F HOISTING, LIFTING, HAULING, OR PUSHING, NOT OTHERWISE PROVIDED FOR, e.g. DEVICES WHICH APPLY A LIFTING OR PUSHING FORCE DIRECTLY TO THE SURFACE OF A LOAD , Hub-, Verhol- oder Schubvorrichtungen, soweit nicht anderweitig vorgesehen, z.B. Vorrichtungen mit unmittelbarer Krafteinwirkung auf die Last |
Three-stage double-acting self-fitting hydraulic jack
Europäisches Patentamt | 2015
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