| 摘要 |
<p>The invention relates to an arch-shaped metal rolled section, used for supporting preparatory and opening mining works. Accroding to the invention, the rolled section comprises two arms (a) interconnected by a thickened area (b), which is smooth or has a prominence (c) at its inner side and at its outer side has another prominence (d), each of said prominences (c and d) being confined by two of some connection surfaces (e and f), said arms (a) having at the ends some thickened heads (g) each provided at its lower side, externally, with a supporting shoulder (i) and a nose (h).</p> |
