| 摘要 |
<p>Control of vertical motion of a suspended crane hook assembly to accommodate vertical motion between a station carrying the crane and a station carrying a load is achieved by a transducer on the hook assembly and a control cord depending onto the load station. Tension above a set value in the cord produced by a crew member on the station causes the hook assembly to descend and below the set value causes it to rise. Movement of the stations causes a continuous adjustment of tension and the hook assembly follows the motion, extra tension being applied to guide the hook assembly down to the load and vice versa.</p> |
