| 摘要 |
A control system is disclosed for selective positioning a displaceable device, in particular the load carrying fork cage of a so-called fork-lift truck, into pre-selected positions or heights. The control system includes spaced apart pairs of associated switch elements, one element of each pair being mounted on a stationary guide, and the other element on the displaceable device. Each element pair defines one of the pre-selectable positions when the two elements are aligned, and in that case they further assume an actuated condition. Each element pair is connected in series with a particular selector switch, and when both the selector switch and the element pair are in an actuated condition, a coupling device is energized to cancel or reduce the load carrying ability. The displaceable device then sinks until the two elements of the actuated pair are separated, whereafter the displaceable device is kept stationary in a well defined position or height. The control system is semi-automatic, very simple and well-suited for mounting on already existing fork-lift trucks. |
