Torque setting mechanism for motor-driven screwdrivers

摘要

A description is given of a motor-driven screwdriver which has a planetary reduction gear which is coupled to a motor shaft and comprises a sunwheel with a multiplicity of first teeth. A torque setting mechanism contains a locking wheel which is arranged coaxially around an output shaft and has a multiplicity of second teeth, a spring seat arranged coaxially around the output shaft, a spring which acts between the locking wheel and the spring seat and normally acts on the locking wheel such that the first and second teeth mesh with one another, and an adjusting drum which is mounted rotatably on a casing of the motor-driven screwdriver and has a cam situated in sliding engagement with the spring seat. If the adjusting drum is rotated about its own axis, the cam effects an axial movement of the spring seat, so that the pressing force exerted by the spring acting on the locking wheel is thus changed. As a result, by rotating the adjusting drum, the torque can be adjusted, in which process the first and second teeth are disengaged.