With a solid-shaft gearbox, the output shaft is connected to the machine by a coupling, pulley or chain and the gearbox sits on a base by its feet or flange. With a hollow-shaft gearbox, the machine shaft passes through the gearbox, which is carried on that shaft. The K series page lists hollow-shaft and torque-arm connection among the common mounting types.

The torque arm stops the gearbox housing from rotating with the machine shaft. For correct installation:

  • the torque arm is anchored to a fixed point, usually through a flexible bush or spring mount; clamping the arm completely rigid transfers shaft runout to the gearbox bearings as load,
  • the bore diameter must match the machine shaft and key size; assembly paste makes later removal easier,
  • the machine shaft's own bearings must carry the radial load.

The hollow shaft diameter depends on frame size; state the machine shaft dimension when ordering. Example series: K series 455 bevel-helical gearbox.