Abstract: Friction driving mechanism for converting a rotating movement of a member into an axial movement of the same and consisting of driving means and to its rotating member connected friction means. The friction means comprises a holder 3, in which there is a number of mutually movable and with the holder 3 in relation to the shaft rotating balls as the axes of rotation of the balls 5 are oblique in relation to the longitudinal axis if the shaft 1. Each of the rotatable balls 5 are according to the invention embedded in rotatable bearing bushes 6. If the shaft 1 meets a stop so that the balls 5 no longer are able to transmit an axial movement to the shaft 1 the axes of rotation of the balls 5 will try to adjust so as to be approximately parallel to the shaft 1. As a result the balls 5 at regular intervals will change position so that the wear is equally distributed over the whole surface of each ball. The advantage is that the friction driving mechanism has a longer lifetime than previously known.

Abstract: Friction driving mechanism for converting a rotating movement of a member into an axial movement of the same and consisting of driving means and to its rotating member connected friction means. The friction means comprises a holder 3, in which there is a number of mutually movable and with the holder 3 in relation to the shaft rotating balls as the axes of rotation of the balls 5 are oblique in relation to the longitudinal axis if the shaft 1. Each of the rotatable balls 5 are according to the invention embedded in rotatable bearing bushes 6. If the shaft 1 meets a stop so that the balls 5 no longer are able to transmit an axial movement to the shaft 1 the axes of rotation of the balls 5 will try to adjust so as to be approximately parallel to the shaft 1. As a result the balls 5 at regular intervals will change position so that the wear is equally distributed over the whole surface of each ball. The advantage is that the friction driving mechanism has a longer lifetime than previously known.