Abstract: A rack for mounting on a segmented mine wall face conveyor and for assisting the movement of a drum mining machine along the conveyor, the rack comprising a series of rack segments aligned substantially in an end-to-end relationship, each rack segment provided with a plurality of equidistantly spaced pins adapted for driving engagement with a pinion of the drum mining machine, each segment rotatably mounted on the conveyor, and adjacent rack segments rotatably joined together by a connection link. Means are disclosed for extending and contracting the connection link relative to each adjacent rack segment, and means are disclosed for maintaining the rack at a relatively constant position relative to the pinion in the region of engagement with the pinion.

Abstract: A device for safety guiding of hauling chain, especially for a ranging drum shearer in coal mining equipment having chain haulage means, consists of chain screening /5/ at a guard /6/ of conveyor /7/ and of chain guides /11/ fixed to a ranging shearer /1/, wherein said guides /11/ travel along the route of conveyor /7/ inside the screening placed at chain guard /6/. The screening of hauling chain /5/ is confined by screening plates /12/, /13/ and /14/ at the upper part of chain guard /6/, having its uncovered side closed by screening end /20/ of a double end lever /15/, pivoted in hub /16/ below the lower screening plate /12/. The retaining end /20/ of double end lever /15/ is closed by the tension of spring /17/, attached by one end to the retaining end /18/ of lever /15/ and by another to a grip /19/ fixed to the body of the guard /6/.

Abstract: A sprocket wheel arrangement adopted particularly for drives in mining machines as, for example, push-plate conveyors and mining equipment. The number of teeth on the sprocket wheel is smaller than the number of seats between the working surfaces of the teeth and cooperating with chain links passing over the sprocket wheel. The seats are open from one side, and are provided with retaining walls only from the side of the teeth. The planes of bottom lands of adjacent seats intersect and form, thereby, an edge. The sprocket wheel arrangement may be used in driving systems of both coil chains and fish-plate chains.