Abstract: A transmission mechanism for a vehicle windscreen wiper arrangement comprises an eccentric driven by an electric motor. A transmission member can be locked either to the eccentric to rotate with it or to a further transmission member which is in turn connected to the linkage of the wiper arrangement. In the second case the wiper arrangement performs a normal on screen wiping motion and in the first case, with the direction of the motor reversed, the wiper arrangement is driven from an on screen to an off screen park position. During this part of its travel the wiper speed is reduced as compared with the normal wiping speed. The mechanism is adaptable to existing wiper arrangements.