| 摘要 |
<p>Application of: Gary D. Tyrell and Robert W. Hill For: Mine Roof Supporting Truss System A truss system is disclosed for use in supporting the roof of a mine. The system comprises an assemblage of elements which permit more rapid and efficient installation than prior art truss systems which have generally been installed as a secondary operation, after the standard, required bolting pattern is in place. The present system, on the other hand, may be installed concurrently with and in fact may become part of, the standard bolting system. The system includes a pair of roof bolts installed in conventional fashion in drill holes extending at divergent angles into the mine roof on opposite sides of the mine opening. The bolts each extend through aligned openings in a bearing support plate and a separate angle block having a curved outel surface. The closed ends of a U-bolt, having a curvature corresponding to the surface of the angle block, extend around the two blocks with the open, threaded ends of the U-bolts facing one another. A pair of blocks having three parallel openings therethrough are placed on the two U-bolts, the open ends thereof extending through the outer openings, and secured with nuts. A rod threaded at both ends, or a plurality of such rods joined by a threaded coupler, extends through the center opening of the block, thereby joining the two U-bolts, and is secured by nuts on each end. The truss is tensioned to a desired degree by threaded advance of the nuts on the U-bolts and/or coupling rods. The angle blocks are disclosed in two embodiments, the first having a planar surface engaged by the bolt head or a flat washer, and the second having an inwardly curved cavity ty surrounding the opening through which the bolt passes and is engaged by a mating washer on the bolt head. The design of the second embodiment permits considerable variation in the relative angular orientations of the truss elements.</p> |
