| 摘要 |
Support means and system for supporting mine roofs, and particularly those areas of mine roofs between ribs of pillars in coal mines. Coal mine roofs frequently consist, at least in part, of shale in overlying strata, and are notoriously weak in tensile and shear strength. Heretofore, mine roof bolts for strengthening installation systems have been known. Bolts of different types, and different installation systems and patterns have been used. Various drawbacks have existed. The present invention teaches a roof bolt manufacture, and an improved installation use system and pattern. The bolts include a pair of coactive elongated steel members. One member is of a general U-shaped configuration and has edges of a generally undulating or stepped wavilinear configuration, with the formed apex portions slightly inturned. The coactive slide member, formed from a partial round bar is shaped to a generally serpentine shape, again of a generally stepped wavilinear configuration broadly similar to the body edges, and having a straight section at one end. The members are operatively intermeshed in use, with the slide being rectilinearly movable with respect to the body member. Intercoaction of the stepped wavilinear configurations creates a lateral separation and force. The slide is punched inwardly proximate the ends to form inner protrusions adapted to be contained between the body edges and prevent respective lateral slippage upon rectilinear movement between the members. The members, upon insertion in a hole in a mine roof, and actuation thereof, create pressures in the material of the mine roof with reinforcement thereof.
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