| 摘要 |
PURPOSE:To carry out return of a brake mechanism immediately after completion of lowering of an elevating member and to simplify structure. CONSTITUTION:A drum brake 25 is installed on a main spindle 3 given rotation in accordance with elevation of an elevating member and a transmission shaft 4 interlocked with the same main spindle 3. In the meantime, a brake release mechanism 36 to hold the same drum brake either in a braking state and a brake release state and a DC solenoid connected to the brake release mechanism 36 and to drive the brake release mechanism 36 are arranged. A top member 7 is screwed on the main spindle 3 free to move. Thereafter, as the DC solenoid is excited and the brake release mechanism 36 is driven, the main spindle 3 rotates and the top member 7 starts to move. Then, a microswitch 56 detects the movement and stops feeding to the DC solenoid 35 In the meantime, a lock member 41 detects completion of movement of the top member 7 and converts the drum brake 25 from the brake release state to the braking state. |
