GB476225A - Improvements in supporting posts or struts specially applicable to pit props - Google Patents

Abstract

476,225. Mine props. GRIFFITHS, E. E., and BATRGATE, R. A. June 3, 1936, No. 15484. [Class 20 (ii)] A telescopic pit-prop is adapted to give a constant resistance to collapse by deformation of an easily renewable member positioned between the movable parts of the prop. In one form, Fig. 1, the prop comprises channel-shaped members 20, 21, slidable one within the other, the outer member 20 having welded to it, stiffening collars 22, 23, acting as guides for the upper member 21. A cross-pin 26 on the upper member is supported in a loop of a deformable member 25 fixed at one end to the lower prop member and bent upwardly about the cross-pin, to bear against the web of the upper prop member, so that movement between the pit-prop members is resisted by the constant resistance of the member 25 to deformation. In another form, Fig. 5, multiple cross-pins 26, which may be in staggered formation, bear against bends in a strip 25 secured at its upper end to the lower prop member, while in yet another .form, Fig. 8, an H-section bar 21 slides in a hollow rectangular tubular member 20, and deformable elements 25 are disposed on each side of the web of the section bar. Fig. 10 shows an arrangement of props as supports for a mine arch 39, 40, having angles 43 to bear upon the upper ends of the collapsable props at each side.