| 摘要 |
<p>The telescopic multi-section lifting jack has the innermost and outermost sections (31,37) connected to end parts co-operating with end pieces (47,46) to provide ball and socket joints at either end of the jack. The lower of the two end parts (38) is of hollow hemispherical form and accepts the lower end portions of all but the outermost (fixed) section (31) when the jack is fully collapsed. In this condition, the upper end portions of the various sections present a stepped conical concavity which partly houses the upper end piece (46).</p> |
