Safety latch for automotive hoists

摘要

A safety latch preventing inadvertent lowering or dropping of an automotive hoist by means of a torsionally biased pawl shaft that automatically self engages with a lateral notch located in the lift at hoist operating height. The backside of a vertically movable gear rack attached to the hoist includes the pawl notch near its lower end and which when raised cooperates with the pawl shaft for effecting a latching relation therewith. The pawl shaft is slotted to embrace the gear rack and is manually releasable for permitting hoist descent by a partial rotation which in one embodiment is effected by manually shifting a bi-stable locking rod. Reset for latching on subsequent ascent of the gear rack is effected by descending engagement of the hoist bolster against the bi-stable locking rod. In an alternative embodiment release is obtained by raising a lift pin which similarly effects partial rotation of the biased pawl shaft. An auxiliary latch in the alternative embodiment prevents self-reset of the pawl shaft until after the notch descends a distance beyond which the pawl shaft and notch could otherwise relatch.