| 摘要 |
1,095,607. Electric hoists. DRESSER INDUSTRIES Inc., July 26, 1966 [Aug. 25, 1965], No. 33679/66. Heading B8B. In an electric hoist comprising a frame 2, a motor shaft 8 on the frame and a brake 14, 15, 18 normally braking the shaft 8, a control shaft 20 normally in a neutral position is oscillatable in either direction to release the brake via a self aligning cam follower 44 and a brake actuator 34. The brake comprising a disc 18 splined to the motor shaft 8 and intermediate two discs 14, 15 rotationally fixed but axially movable relative to the shaft 8, is applied by the actuator 34 which pivots about points 35 under the force of a spring 47 and compresses the discs together. The cam follower 44 is a slack fit on the shaft 20 whereby it can align itself in diametrically opposed V- grooves forming a cam track on the end of the brake actuator 34. Oscillation of the shaft 20 in either direction by a lever and rope arrangement, causes the cam follower 44 to ride the cam track on the actuator 34 and pivot the same into the brake release position. Oscillation of the shaft 20 also operates a motor reversing switch 13 via a rack 31 and pinion 32. The direction of motor drive depends on the direction of oscillation of the shaft 20 which is returned to its neutral position by a spring 25 when the rope and lever arrangement is released. |
