发明授权
US4382721A Mine roadway support stilt 失效
矿井巷道支撑高耸

Mine roadway support stilt
摘要:
A mine roadway support stilt includes, on two opposing faces thereof, a plurality of deformable, longitudinally extending indentations and, on the remaining faces, additional indentations to inhibit improper insertion of the I-beam joist support normally received in said stilt.
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