Improvements in chain coal cutting machines for use in mines

摘要

521,611. Coal-cutting machines. MUSCHAMP, N. J. Nov. 23, 1938, Nos. 34024/38 and 23064/39. [Class 68 (i)] Relates to chain jibs for coal-cutting machines having fixed and movable parts, an interposed spring unit allowing limited reciprocatory movement of the movable part, and means associated with the spring unit for adjusting tension of the chain. In Fig. 1, the jib body is slidable on a post E to which is bolted a sleeve A containing a spring C pressing on an inner sleeve B with a flange F or abutments limiting its movement into the sleeve A; the flange F bears against the integral or attached head H of a screw G engaging a phosphor-bronze nut in the jib body. The movement allowed is insufficient to allow the chain to leave the chain race or driving sprocket. The arrangement of the parts may be reversed, or the sleeve A may be omitted, the spring C and sleeve B then being received in a recess in the post E. In Fig. 3, the spring unit is carried by the jib body, the screw G is held against rotation by a block on its outer end, and adjustment is effected by a nut H. The screw may be protected by a sleeve attached to the nut H and passing through the special unit. In another form, the jib body is fixed to the post E and has a slidable outer end between which and the body, the spring unit and adjusting means are arranged. The spring units may be packed with grease, or two spring units may be provided one on each side of the adjusting screw or each provided with an adjusting screw.