Abstract: A torque limiting coupling including: (a) an input gear (7) and an output (8) gear interconnected by a torque limiting device; (b) gear chain (9) interconnecting the input and output gears; and (c) a torque limiting device which retains the gear train (7, 8, 9) to prevent relative rotation of the gear train (7, 8, 9) and the input (7) and output gears (8) to provide a 1:1 input output ratio below a predetermined level of input torque and releases the gear train to allow relative rotation between the input (7) and output gears (8) at or above the predetermined level whereby excess torque is dissipated.