Abstract: A truss has a pair of parallel and longitudinally extending chord rods and transverse rods interconnecting the chord rods. First and second slides each have a pair of tubes each fitting over a respective one of the chord rods and slidable longitudinally therealong and a cross member rigidly interconnecting the tubes and formed with a throughgoing hole through which passes a respective anchor member projecting from a tunnel or mine wall. The slides can be longitudinally fixed on the rods.

Abstract: A truss has a pair of parallel and longitudinally extending chord rods and transverse rods interconnecting the chord rods. First and second slides each have a pair of tubes each fitting over a respective one of the chord rods and slidable longitudinally therealong and a cross member rigidly interconnecting the tubes and formed with a throughgoing hole through which passes a respective anchor member projecting from a tunnel or mine wall. The slides can be longitudinally fixed on the rods.

Abstract: An adjustable support column for use between ceiling and floor surfaces of a mine has an outer tube having an outer end braced against one of the surfaces and an inner end and an inner tube having an inner end in the outer tube at the inner end thereof and an outer end braced against the other surface. The tubes are coaxial to an upright axis and a wedge ring carried externally on the inner tube is tapered toward the outer tube and engageable in the inner end of the outer tube for resiliently resisting telescoping of the inner tube into the outer tube with a predetermined force and for permitting telescoping of the inner tube into the outer tube when the tubes are pressed axially together with a force greater than the predetermined force. Formations on the inner tube engage the ring for axially displacing the ring along the inner tube and fix the ring on the inner tube at any of a multiplicity of locations therealong.

Abstract: An adjustable column for use between ceiling and floor surfaces of a mine has an outer tube having an outer end and an inner end and an inner tube having an inner end in the outer tube at the inner end thereof and an outer end. The tubes are coaxial to an upright axis and an external screwthread on the outer-tube inner end fits with an inner screwthread on the inner-tube inner end so that the tubes can be screwed relative to each other to change the axial length of the column. One of the outer ends is operatively braced against one of the surfaces and the other outer end is spaced from the other of the surfaces. A resiliently compressible support element is braced axially between the other outer end and the other surface.

Abstract: A mine prop has a post or column formed by two telescopingly interfitted tubes, one of which has a bottleneck configuration over which the other is spread to provide a resistance to telescoping contraction. At the upper end, a nut is rotatable on the post and can advance the threaded spindle engaged therein to brace the prop between the roof and ceiling of a subterranean structure.

Abstract: A peripherally flexible arch for propping rock structure for mining tracks, tunnels or the like is comprised of a plurality of partially overlapped elongated segments, each of which has an end portion extended toward the rock structure, a bottom portion opposite to the end portion, and a lateral flange offset from the end portion laterally and in the direction toward the bottom portion. Clamping devices are arranged at the ends of the overlapping regions of the segments to clamp the segments to each other. The end portion of each lower segment is inserted into a groove formed between the end portion and the flange portion of each upper segment at the side of this segment facing away from the rock structure. Each clamping device has a hook engaged in a groove formed between the end portion and the flange of the upper segment at the side of this segment facing toward the rock structure.

Abstract: A clamping device for connecting a number of shaped, elongated, flanged through sections of a support structure to each other includes an upper stirrup, the flanges of which are supported on the flanges of the upper through section, a lower stirrup positioned to support the flanges of the lower through section, and clamping bolts extended through the openings in the flanges of the stirrups and the through sections and tightened with nuts. The head of each bolt has supporting projections provided with convexly curved portions which are engaged in the flanges of the upper stirrup in a form-locking fashion.

Abstract: A wall element for an underground gallery has a W-shaped member which is symmetrical relative to its y-axis and has an axis of gravity coinciding with its x-axis and lying at approximately the center of its side, wherein the thickness of its lateral flange portions, base portions and connecting web portions are selected so that, in relation to used weight per meter, the W-shaped member has a maximum possible moment of resistance relative to the x-axis and a maximum possible bending load capacity in the plastic deformation range, and the W-shaped member has such a profile and such thicknesses of these portions that it has at least approximately equal bending load capacities in the plastic deformation region in two opposite directions along the y-axis.