Disclosed is a mechanism to open and close windows and to automatically close doors. A roller car (9) is operated along the centre line of a primary slide track (4) causing a roller (7), affixed to the roller car (9), to exert force upon one or the other side of a slot (8) in the operating member (1) which is pivotally affixed to the primary slide track (4) at one end, to operate a secondary slide track (6) through a pivotally mounted slide (5) on the outer end of the operating member (1). The centre line of the primary slide track (4) and the centre line of the slot (8) in the operating member (1) cross each other at a substantially constant acute angle (13). When the roller car (9) is fitted with a spring which provides constant tension in a direction away from the operating member's (1) pivot point (2), it causes the closer to close automatically. The angle (13) may be varied to increase or decrease the speed and force of operation.