ANTI-REVERSE CLUTCH SAFETY DEVICE

A conventional over-running clutch-type "no back" mechanism normally backstops or grounds out a drive shaft in the event of a load thereon tending to cause reverse wind-up at clutch elements of the mechanism; and the latter is equipped with a safety device which signals the presence of excessive wind up or slip condition. The device is applied coaxially to the mechanism's drive shaft, and includes a sprag assembly torqued reversely in response to such undue slip or wind-up. The assembly is interposed radially between an outer rotatable race, and a cylindrical stud providing an inner race, both races being coaxial with the shaft; and the stud is coupled to rotate with the latter in its driving phase, in which the stud over-runs relative to the outer race. When shaft backstopping is in effect the sprag assembly transmits that torque to the outer race; and in response the excessive wind-up or slip, as picked up by the sprag assembly, the latter causes the outer race to rotate a bit. This minor rotation enables a part of the outer race to cammingly close an electric limit switch, thus originating a signal to audibly or visibly alert an attendant.