Winch or hoist with a friction brake device

Claim 1

In a load-lifting and lowering device including a rotatably mounted drive shaft, load-engaging means connected to said drive shaft, and movable by rotation of said drive shaft to lift and lower a load, the improvement that comprises a cylindrical brake drum surrounding one end of said drive shaft, a plurality of segments, meaNs surrounding said shaft and driven thereby for mounting said segments for radial movement toward and away from the inner surface of said drum, the inner surfaces of said segments being conical, a rotary brake operating member so threadedly connected that relative rotation between said operating member and said shaft causes endwise translation of said operating member, a conical wedge centrally located among said conical inner surfaces of said segments, the inclined surfaces of said wedge being out of parallelism with the adjacent conical inner surfaces of said segments, tapered rollers interposed between said conical wedge and the conical inner surfaces of said brake segments, said rollers being so shaped and arranged as to bear against said inclined surfaces of the wedge and said conical inner surfaces of said segments while being free of roll therebetween so that any relative angular motion of said mounting means and said shaft causes axial movement of said rollers with positive outward displacement of said segments.