| 摘要 |
<p>A device for stepwise lifting heavy loads, wherein one or more units each consists of a vertical support member resting on a rigid bed and accommodating a lifting member vertically displaceable in the support member; supporting elements shorter than the length of displacement of the lifting member, one such supporting element being insertable into the support member above the lifting member in its lowered position in order, upon upward displacement of the lifting member, to be introduced into a vertical guiding tube aligned with the support member, the load resting on top of the uppermost supporting element in the guiding tube; and a support plate insertable between the guiding tube and the support member in engagement with the top end surface of the latter, the support plate permitting vertical displacement of the supporting element resting on the lifting member when the supporting element is situated partly within the support member, but preventing downward displacement of the supporting element when it is completely inserted into the guiding tube.</p> |
