Improvements in or relating to roof supports adjacent to the working faces of mines of coal and other stratified minerals

摘要

839,942. Mine roof supports. SWALLOW, F. C. Feb. 13, 1959 [June 3, 1958], No. 17613/58. Class 20(2) A mine roof support, for use adjacent to the working face, is of square or rhombus form latticework, in which each member is a girder of twice the length of unit lattice-spacing. One form of girder described is of hollow rectangular form, Fig. 1, and carries means B at its mid-point to engage adjacent girders of the same type. Holes C are provided for the insertion of wedges F, which lock the leading girders of the network to those previously set, Fig. 5, enabling them to act as cantilevers, props being placed under all crossing points. An alternative form of girder (Figs. 2, 4, not shown) is of I-section, with corresponding engagement means. The arrangement allows the rearmost row of girders to be remotely dismantled and recovered by the use of ropes or cables. The network may be set up either as in Fig. 5 or with the girders along and perpendicular to the line of advance.