A new or improved coupling for sectional roof-supporting arches applicable for use in coal mines and the like

摘要

320,972. Rothwell, N., and Smith, J. W. Aug. 2, 1928. Shoring; ironwork, constructional.- Sectional ironwork arch-forming members for use in mines are joined together by means of one-piece sleeves 2 shaped to fit approximately the section metal and secured in position by means of wedges 3 passing between the sleeve and the arch members. The sleeve may surround the whole or only a part of the section metal but bears on both sides of the web of the section. Sight holes 4 may be provided in the sides of the sleeve which may also be stiffened by ribs.