| 摘要 |
A frame elevating mechanism having first and second frames vertically spaced from one another. The first frame is configured to be supported on a floor surface. The second frame has a pair of longitudinally spaced elongate guide tracks extending coextensively with each lateral side of the second frame. Lever arms are provided on the first frame and include at the distal ends thereof a follower member operatively coupled to a respective one of the guide tracks. Each of the aforesaid lever arms has thereon an elongate second guide track configured to receive thereon a distal end of one of the arms of a two arm lever pivotally mounted on the first frame. Drive mechanisms are provided which operatively engage the second arm of the two arm lever to effect a change in elevation of the second frame relative to the first frame.
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