Original Publication Date: 1985-Aug-01
Included in the Prior Art Database: 2005-Feb-19
A screwdriver to be used manually or in a robotic system has a torque limiter which, when the torque limit is reached, applies further torque in a series of pulses. Higher ratio gearing than is normal in screwdrivers can be used, thus allowing higher initial screw run in speeds. Also, torque reaction is reduced at the final torque limit since the pulses are mainly reacted by inertia within the driver. A screwdriver blade 1 (Fig. 1) carries at its upper end a flanged ring 2 having an internal cam face 3. The face 3 (Fig. 2) is in two halves, each of which has a flat inwardly inclined part 4 leading to an outwardly curved part 5 leading to a curved part 6 concentric with the ring 2. Depending into the ring 2 is the output shaft 7 of a motor assembly.