| 摘要 |
<p>The system lifts a load until it comes into contact with the underside of an I-section girder forming part of a structure. Brackets (1, 2) with V-shaped notches in them are mounted in pairs on the top flange (a) of the girder, and a rope aor chain is reeved round pulleys in each bracket of a pair, so that a free end hangs down from each bracket, on opposite sides of the girder. One end is secured to the load, which is lifted by hauling on the other rope end until it comes up against the lower flange of the girder (A). Three pairs of brackets can be used for a lift, each having side plates in which V-shaped notches are cut, the top edge of the notch being horizontal so as to rest on the top girder flange. A pair of pulleys is mounted on a spindle (4) passing through the two sides plates.</p> |
