| 摘要 |
A drum driving device for a window shade includes a housing (2) fixed to a frame (1) of the window shade. A cord pulley (4) is rotatably received in the housing (2). A drum (6) is rotatably mounted to a drum shaft (5) received in the housing (2). A single-direction clutch device (7) is mounted between the drum (6) and the cord pulley (4). The clutch device (7) includes a chamber (8) defined in the housing (12). A driving shaft (9) is coaxially mounted to the cord pulley (4). A transmission shaft (10) is mounted in the chamber (8). A driving spring (11) is mounted to an inner periphery of the chamber (8) and around the driving shaft (9) and the transmission shaft (10) in the chamber (8). The transmission shaft (10) has an outer diameter not larger than that of the transmission shaft (9). The driving spring (11) is in tight contact with the driving shaft (9) and the inner periphery of the chamber (8). The transmission shaft (10) is extended out of the chamber (8) and connected to the drum (6). |
