| 摘要 |
<p>The mine roof support plate (10) is used with a bolt in the ground with a load of over 1430 kg. It is made from a rigid rectangle (12) with a raised central part (16) relative to the edges (14). The centre has a base (18) with a central hole (20). The base in rectangular with rounded angular edges. The plate is of equal thickness throughout, between 4.2. and 3.4mm. The hole is circular and the base is raised from the rest of the plate by about 25.4mm. The base has a flat bearing surface (20) around the hole and is at least 3.8mm wide.</p> |
