| 摘要 |
1. Actuating and fastening device for roller curtains having a stationary part (1) with a first coupling surface (1b) and a hub (2) which is axially movable and rotating with respect to the stationary part and by its rotation causes the winding and unwinding of the roller curtain, respectively, said hub having a second coupling surface (2b) cooperating with the first coupling surface, this second surface being pressed against the first coupling surface under the action of a resilient means (5) operating the movable hub (2) in order to brake it, at least one ball being provided arranged between the movable hub (2) and the axially stationary part (1), said ball being urged in a wedge-like narrowing slit between a surface (1a) provided on the axially stationary part (1) and the movable hub (2) by means of cam surfaces (3a) provided on a driving member (3) whenever the driving member is rotated relative to the movable hub (2), in order to raise the coupling surface (2b), until at its final fastened position said ball causes the rotary connection between the driving member (3) and the movable hub (2), characterized in that the balls (4) are arranged in a radial guideway (2a) provided in the movable hub (2) ; that the wedge-like slit inwardly radially narrows ; that the driving member is a ring (3) covering from the outside the wedge-like slit, which ring has on its inner periphery the cam surface (3a) formed so that, by turning the ring (3) relative to the movable hub (2), it inwardly radially urges the ball (4) in its guideway (2a), axially displacing the movable hub (2) and lifting its second coupling surface (2b) ; that the cam surface (3a) then urges the ball to a final position against a radial stop, so as to clamp it between the cam surface (3a) and one side of the guideway (2a) and transfer the rotary motion from the ring (3) to the movable hub (2) ; and that the wedge-like slit has such an inclination that at the end of the driving torque the ball is radially outwardly moved back under the axial pressure of the resilient means (5) acting on the movable hub (2). |
