| 摘要 |
The invention relates to a device for rapid positioning of a heavy trolley 301. The trolley 301 is finely positioned by means of a fixed positioning rod, for example a gear rack 302, and an interacting rotary element, such as a gearwheel 305, which latter is driven by a motor fixed to the trolley 301. The trolley 301 is rapidly and crudely displaced by means of a further member, this further member being able to be constituted by one more gearwheel 401, which interacts with the gear rack 302 and is driven by a separate motor fixed to the trolley 301. This further member additionally supplies a certain force in the final positioning by means of the gearwheel 305, so that the play between the gearwheel 305 and the gear rack 303 is eliminated by pretensioning. Instead of a second gearwheel 401, a toothed belt or a pneumatic cylinder can be used. <IMAGE> |
