| 摘要 |
<p>The lifting hook for sheet material has a main body made from two side plates which enclose between them a main arm and an auxiliary arm hinged together by a pin through the top. The main arm has a curved segment with a corrugated face which is swung against a corrugated flat surface projecting from the auxiliary arm. These grip the sheet between them. The main arm carries a cylinder with a spring inside with a swinging arm connecting it to an extension of the curved segments, acting as a return mechanism. The top of the swinging arm engages a curved slot in each side plates, so that the cylinder is guided as the sheet is gripped. The curved segment is released and locked by a trigger which swings inside the gap between the two arms.</p> |
