In general, a scissor jack is described. A typical embodiment includes four arms (4) hingedly arranged to provide two opposite elbows between a base (10) and a load support (11), a pair of trunnions (2, 2.1), one at each elbow connected by a partially threaded shaft (12) with one end of the shaft rotatably engaged in the threaded trunnion (2.1) to extend beyond the outer corner of the elbow.Located on the shaft and between the outer two trunnions is an assembly comprising a pair of levers (3) pivotally assembled on a third trunnion (5) which forms the one end of a double yoke (1) comprising two rods slideably passing through the outer trunnion (2) and beyond the elbow. In contact with and operating against the inner trunnion (5) is a thrust bearing (9) fixed in portion on the shaft by means of a flange. Springs (6) are attached to individual levers and the corresponding arms for alignment purpose.Fully collapsed the angle of operation of the first stage of the lever in contact with the pivot point (8) is such that it simulates the same optimum angle of a typical scissor jack at approximately 75% of it's range. Once the first stage of the lever is fully extended the second stage takes over at pivot point (7) when it is again at the optimum angle. Once the second stage of the sever is fully extended the jack itself is in an optimum height for further lifting. Thus the jack is able to utilise the full extent of it's range of motion.
Scissor Jack
15.07.2021
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 |