GN 327 safety handwheels feature the ultimate in health and safety at work standards because the handwheel, if disengaged, is mounted on a fixed component, the bearing flange. The wheel is fully disengaged from the rotating shaft.
The bearing flange can also accept the bearing of the shaft via the bearing bushing (code No. 1). This bearing bushing is a dry bearing (DU bushing). Normally, the shaft has a separate bearing and the bearing bushing serves to center the bearing flange.
Centering can also be effected by a centering ring (code No. 2) if the appropriate bore hole has been made at the machine side. In this case there is no need for the bearing bushes and no bearing friction (heating) will occur.