Abstract: 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.

Abstract: The disclosed safety latch is operable with automotive hoists that have a rack gear connected to and movable with the hoist piston. The piston, which carries the hoist superstructure, is disposed in a cylinder so that the piston telescopes to raise and lower the hoist in response to hydraulic or pneumatic pressure acting thereon. A pinion gear mounted on the latch is in engagement with the rack and, through a slip clutch mechanism, drives an operating lever that is connected with a latch dog for securely engaging the rack to prevent movement of the rack and the piston downwardly with respect to the cylinder. The latch operating mechanism can be operated manually to completely disengage the latch dog from the rack whereby the hoist may be lowered. The slip clutch mechanism is provided with a lost motion coupling member between the latch operating member and the latch dog so that the latch dog remains in engagement with the rack should the system for raising the hoist become inoperative.