Abstract: A machine carriage, for example for a mine roof support, has a beam with rounded ends around which an articulated track runs in a guide path which defines lateral clearance at each side of the track on the straight part of the path. The track is guided without play around the rounded ends of the beam.

Abstract: A channelling machine for cutting a preliminary groove around the working face of a tunnel being excavated. A guide and drive track assembly comprising at least two guide rails and a drive rail displaceable into the immediate proximity of the working face. The guide and drive track assembly is disposed entirely inside a hollow support frame of cross-section complementary to that of the tunnel being excavated. The guide and drive track assembly also includes a back-up rail likewise disposed inside the support frame. Another guide and drive track assembly may be provided symmetrical to the first. The machine is braced against the walls by a plurality of front and rear hydraulic cylinders which also adjust the alignment of the machine in the tunnel. The machine is mounted for displacements on a cradle.

Abstract: A hauling device, for example for a mining machine, has two clamping elements which grip on ramps each of which elements is attached to an operating rod of a hauling jack. The jacks are operated alternately, in conjunction with the clamping elements to advance or retract the machine, and the hauling jacks are hydraulically interconnected in a manner to avoid hunting.