Abstract: The present invention discloses a scissor jack comprising four arms hingedly arranged to provide two opposite elbows between a base and a load support. A pair of trunnions are provided with an outer trunnion at one outer elbow and a threaded trunnion at another outer elbow opposite to the one outer elbow connected through a threaded shaft. The inner third trunnion is connected to two rods to form a yoke. The yoke is configured to slideably pass through the outer trunnion of the one outer elbow to extend beyond the one outer elbow. A pair of levers are provided which are configured to be secured to the inner third trunnion. The scissor jack further comprises springs or any other retaining mechanism attached to a pair of levers, to ensure that the pair of levers return to their original location or position when the scissor jack is lowered.

Abstract: 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.