Abstract: A mining machine is disclosed comprising a mobile base and a cutting head assembly at a forward end of the mobile base having a cutter drum rotatable about an output shaft disposed along the longitudinal axis of the cutter drum. A drive system for the cutting head assembly comprises at least one motor for driving at least one toothed motor pinion and a generally cylindrical combination gear having generally circular end surfaces. A bevel or face gear is formed in at least one of the end surfaces, having teeth adapted to mate with and be driven by the toothed motor pinion. The combination gear has a worm gear formed in the outside cylindrical surface, which is disposed in driving engagement with the teeth of an output gear integrally and coaxially connected to the output shaft of the cutter drum.

Abstract: Stretching of a conveyor belt to prevent edge spillage during horizontal turns is achieved with a new and improved chain extending longitudinally of the belt intermediate its side edges and secured to the belt. The chain is formed of alternate links, one of which is a C-shaped link secured to the belt and the other of which is a connecting link adapted to be engaged by a twin-drive sprocket. The links are loosely fitted such that the C-shaped links can be secured to the belt with a minimum distance between links and thereafter pulled apart to stretch the belt to which the chain is attached.