AN APPARATUS INCLUDING AN ADJUSTING SYSTEM FOR ADJUSTING A ROTATIONAL POSITION OF A SHAFT WITH RESPECT TO A SHAFT HOLDING MEMBER

摘要

An apparatus (1) includes an adjusting system for adjusting a rotational position of a shaft with respect to a shaft holding member, comprising a frame (2), a shaft (15) which is rotatably supported by the frame (2), a shaft holding member (19, 21) which is linked to the frame (2) and which is connectable to the shaft (15), wherein the shaft (15) is rotatable with respect to the shaft holding member (19, 21) about a centreline (5) of the shaft (15), wherein the adjusting system is provided with a driving source (6, 9) for applying a torque on the shaft (15), a friction coupling (F) for connecting the shaft (15) and the shaft holding member (19, 21) to each other and blocking the shaft (15) and the shaft holding member (19, 21) with respect to each other in rotational direction of the shaft (15), a spring (22) for applying a predetermined force on the friction coupling (F) so as to create a predetermined friction force at the friction coupling (F), an actuator (17) being in engagement with the spring (22), an electromagnet (20) for exerting a force on the actuator (17), wherein the spring (22) and the actuator (17) are adapted such that under operating conditions the force on the friction coupling (F), caused by the spring (22), in a non-operated condition of the electromagnet (20) is higher than a force on the friction coupling (F) in an active condition of the electromagnet (20).