| 摘要 |
Two telescopic lifting beams are loaded in their protruded position and are driven from a retracted position to a protruded position. In order to improve the bending strength of the lifting beams, the lifting beams are surrounded by two telescopic tubes, one of the tubes being fixed to the outer end of the telescopic first lifting beam and is slideable on the second telescopic tube, which extends inwardly on the second lifting beam. |
