| 摘要 |
A drive arrangement (100) for moving a moving frame of a window or door unit comprises a transmission (102) for coupling to the moving frame such that the transmission (102) can effect opening and closing movement of the moving frame. The drive arrangement (100) further comprises a freewheel clutch (104) having an inner race and an outer race, with one of the inner and outer race being rotatable upon movement of the moving frame. The drive arrangement (100) further comprises a device (106) for selectively allowing or preventing rotation of the other of the inner and outer race. The drive arrangement (100) allows the moving frame selectively either to be allowed to move in both the opening and closing directions, or to be restricted to move in only one direction. |
