Abstract: A scissor jack for handling heavy duty work includes four arms hingedly arranged to provide two opposite elbows between a base and a load support, a pair of trunnions, one at each elbow connected by a threaded shaft. One end of the threaded shaft is rotatably engaged in a threaded bush anchored to one elbow on a trunnion to extend beyond the outer corner of the elbow. The jack further includes a movable brace comprising a block slidable on the threaded shaft and carried between a pair of plates which are pivotally secured to the connectors and bent to provide stops for simultaneous location of the arms with spacers on the trunnions to determine the extended position of the jack.

Abstract: The invention involves a scissor jack having four arms hingedly arranged to provide two opposite elbows between a base and a load support. A pair of trunnions at the elbows is connected by a threaded shaft. A movable brace is supported between the arms. The brace strengthens and adds support to the jack assembly. In a preferred embodiment, the brace includes a guide assembly which slidably engages the shaft and connectors pivoted between the guide and each of the four arms. The connectors are extensible socket and rod arrangements. Each connector includes a coil spring located over the rod in the socket. The four springs are compressed on extension of the jack to assist in lifting a load.

Abstract: A scissor jack for handling heavy duty work includes four arms hingedly arranged to provide two opposite elbows between a base and a load support, a pair of trunnions, one at each elbow connected by a threaded shaft. One end of the threaded shaft is rotatably engaged in a threaded bush anchored to one elbow on a trunnion to extend beyond the outer corner of the elbow. The jack further includes a movable brace comprising a block slidable on the threaded shaft and carried between a pair of plates which are pivotally secured to the connectors and bent to provide stops for simultaneous location of the arms with spacers on the trunnions to determine the extended position of the jack.