| 摘要 |
A crane having at least one movable member and a drive for moving the movable member wherein the control for the crane permits an operator to controllably vary the direction and speed of movement of the movable member. Adaptation of the control to cranes of otherwise conventional construction or to pre-existing cranes is facilitated by an advantageous electrical circuit arrangement, in which direction and speed signals are conducted through a minimum number of electrical conductors in accomplishing the controlled variation of direction and speed of movement.
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