Abstract: A locking mechanism for releasably locking a wheel to a rotatable hollow shaft having a terminal end includes expandable segments located axially outwardly of the shaft terminal end, and an expanding rod extending through the shaft and segments. Axial movement of the rod relative to the shaft and segments selectively expands the segments outwardly into releasable locking engagement with a sleeve positioned over the segments.

Abstract: A safety lock device for lifts or the like includes a pair of elongated inner and outer members. The inner member is movable longitudinally relative to the outer member between a retracted position and a plurality of extended positions. The lock device includes friction brake means carried by the inner member for automatically locking the inner member against movement toward its retracted position from any extended position. The brake means provides free extending movement of the inner member from its retracted position to its extended positions. A selectively operable releasing means is movable from a brake armed position to a brake releasing position for providing movement of the inner member from any of its extended positions to its retracted position. Operating means automatically move the releasing means to its brake armed position upon movement of the inner member from its retracted position toward its extended positions.