| 摘要 |
<p>A hoisting system comprises a power-driven hoist unit (16) attachable to a ladder, and a load-carrying trolley (6, 8) arranged to run along the stiles (5) of the ladder (3). The hoist unit is a self-contained power-driven unit comprising a DC motor (A) with electronic zero current switching to provide a power unit of compact form. The hoist unit may be mounted on scaffolding instead of on a ladder</p> |
