US Patent 8490445 Electric door lock

A door lock includes a first driven wheel connected drivenly to a motor and having two resilient driving elements, and a second driven wheel connected drivenly to a rotary handle and the first driven wheel. The second driven wheel has a driven element disposed between and driven by the driving elements so that the second driven wheel moves to a first or second position to place a latch bolt in a latching or unlatching position. When the latch bolt is jammed, the second driven wheel is inoperative. However, as the driving elements are resilient, the first driven wheel can continue its rotation without being obstructed.