| 摘要 |
Apparatus for positioning and moving heavy elements relative to one another is disclosed. The apparatus comprises a pair of spindles threadably engaged in opposite ends of an elongated protective socket member. Each spindle is provided with a pair of axially spaced slide surfaces engaging with cooperating surfaces on the socket for minimizing the flexural or bending strain on the spindle. At least one slide surface of each spindle and its cooperating socket surface is arranged to prevent disengagement of the spindle from the socket. A synchronizer element, having polygonal ends, is axially mounted in the socket member, the polygonal ends of which synchronizer element engage in differently-shaped polygonal bores in a respective spindle to permit relative rotation between the spindles of a maximum of 90 DEG and to prevent one of the spindles from being threaded either to its extended or retracted position independently of the other spindle. |
