| 摘要 |
An operating unit (5) for operating a window covering. The operating unit (5) includes a housing (11), a rotatable drive pulley (13) having an axis of rotation and first and second mounting positions in the housing, with respect to the axis of rotation, an engagement device (15), rotatable about the axis of rotation, and a brake mechanism (45, 47, 49) for, in use, arresting the engagement device when the drive pulley (13) is not rotated and preventing the engagement device and drive pulley from being back driven by the window covering. The engagement device (15) has a plurality of circumferentially spaced pins (19) parallel to the axis of rotation. The drive pulley (13) has a corresponding plurality of openings (17) facing the pins (19). In the first mounting position, the pins on the engagement device (15) engage with the corresponding openings (17) in the drive pulley and the engagement device rotates with the drive pulley. In the second mounting position, the pins (19) do not so engage and the engagement device (15) thereby can rotate relative to the drive pulley (13). |
