| 摘要 |
A locking pulley assembly includes a pulley adapted to be affixed to a surface, a pull handle, a swivel hook, and a cord extending between the swivel hook and the handle around the pulley wheel. The pulley includes a unitary pulley wheel having locking grooves and coaxial frustoconical bearing surfaces, the pulley wheel being mounted for rotation in a unitary frame having inwardly facing frustoconical bearing surfaces engaging the bearing surfaces of the pulley wheel to form a rotatable joint. The handle is comprised of a cylindrical member having a central axial hole with reduced diameter at its central portion for holding a knotted end of the cord. The handle also has a slot at each end thereof of width slightly less than the diameter of the cord, to enable the handle to hold the cord. The swivel hook has a first element adapted to be affixed to the other end of the cord, and a hook pivotally mounted on the first member. In the formation of the pulley, the frame and pulley wheel are sequentially cast, with the bearing surfaces of the first cast member forming the bearing surface part of the die for the casting of the second element. The frame is cast with bowed sides, and these bowed sides are straightened by compression to free the rotating joint. |
