| 摘要 |
A primary mining post, prop, or support that is yieldable to the settling forces of a mine shaft and has a double ball and socket configuration to respond to the shifting that occurs with roof settling in mine shafts. The post has a ball on each end of the main support body and corresponding sockets in each of the respective top and bottom bases. The main body has means for yielding to the heavy weights put thereon. The double ball and socket configuration allows the heavy weights of a settling subterranean roof to be fully transmitted axially along the length of the main body of the post during off vertical loading without undue buckling and failure. The loading characteristics remain virtually identical with straight vertical and off vertical loading. Traditional supports will buckle and fail under a shifting load since the load forces are distributed differently under a non vertical load.
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