| 摘要 |
The device comprises an electrically operated motor 10 for driving a rotating wheel 19 that drives a wire 18 arranged as a loop. Attached to the wire are carriages 20, preferably arranged on opposing wires of the loop so that when the wheel 19 is rotated the carriages on opposing wires move in opposite directions, so as to both simultaneously close or open the curtains. The motor 10 drives the wheel 19 via shaft 12 and an electromagnetic clutch 1, the motor and the clutch being both activated or deactivated at the same time by a control circuit 15, so that, when the motor is deactivated, the clutch is not engaged and the wheel 19 can rotate independently, thereby permitting the manual drawing of curtains in an effortless manner. The clutch comprises a first part (2, Fig.1), a second part (3, Fig.1), a magnetising coil (4, Fig.1) positioned over the second part 3, and a toothed wheel (5, Fig.1) that is fixedly connected to a stud (8, Fig.1) of the second part 3. When the coil is inactive, parts 2 and 3 rotate freely with respect to each other and when it is energised they magnetically engage to transmit the rotation from the motor to the toothed wheel 5 and then to wheel 19. |
