BREAK-AWAY KNOB DRIVER

摘要

A keyed lever handle for a cylindrical lock is rotatably mounted by its neck on the knob sleeve of the lock and is connected to rotate the sleeve by a driver having a drive lug which breaks away under a predetermined high torque so as to protect the lock mechanism from excess torque. The driver is mounted in two opposite slots in the sleeve and the drive lug projects radially through one of such slots into positive engagement with an inward-opening recess in the knob. The lug is preferably formed with an end recess which leaves two upstanding ears at the sides of the lug which are adapted to shear in the shear plane between the knob and sleeve under excess torque. The driver is preferably trapped in place in the sleeve by the knob, but for assembly and service purposes is also held by a resilient rubber ball or the like received in an opening in the driver and resiliently engaged with the edge of the opposite slot in the knob sleeve.