发明名称 MINESHAFT CLOSURES
摘要 <p>IMPROVEMENTS RELATING TO MINESHAFT CLOSURES The present specification discloses a disclosure for sealing off dis-used open mineshafts. The closure comprises an open topped basket-like framework which has a polygonal shape with a side wall which tapers from the open top towards the base of the basket-like framework. The base has a conical shape with the apex of the conical shape extending inwardly of the basket. When at least partially filled with infill, the conical base positions the infill adjacent to the side wall and tends to force the side wall outwards, securing the basket-like framework in a mineshaft.</p>
申请公布号 CA1247383(A) 申请公布日期 1988.12.27
申请号 CA19850494926 申请日期 1985.11.08
申请人 FORD, ROBERT E. 发明人 FORD, ROBERT E.
分类号 E21D7/00;(IPC1-7):E21D1/00 主分类号 E21D7/00
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