Switching device for variable speed gears in machine tools

摘要

A switching device for variable speed gears in machine tools having an assembly which includes a plurality of axially disposed, rotatably-driven cam discs, each of which is associated with an electric microswitch. Non-rotatable spacers serve to position the cam discs. A spherical key bed clamp axially clamps the cam discs together while permitting rotation of individual ones thereof. A non-rotating indicating disc displays the present RPM or respective gear stage. A shock absorber in the individual gear trains between switching bars and their respective electric motors provides sufficient damping and cushioning to prevent a hard start-up impact when the motor is switched on or when a sliding gear block is engaged. The shock absorber may include an elastic linkage or an elastic spur gear in a toothed wheel gear reduction unit located between the motor drive shaft and the link shaft.