An arrangement of a sensor on a wheel bearing unit, the sensor is fixed to an outer wheel bearing ring of the wheel bearing unit, and at the sensor is located opposite an encoder of the wheel bearing unit which encoder can rotate with respect to the sensor about an axis of rotation of the wheel bearing unit. The apparatus may comprise a housing that may be attachable to a portion of the surface. The period of time is at least as long as the time required for a front clamp of the sheet material article trimmer to grip the sheet material article against the front table. The inner barrel is provided with a receptacle for housing batteries and a light emitting object that goes through a top end of the first main body when the inner barrel is inserted into the first main body. The bending device includes a fixing base on which the bending mechanism is mounted, and an articulated robot on which a chuck mechanism for holding the workpiece is mounted and which moves the chuck mechanism.