Abstract: A power supply system for a drum-cutter mining machine utilized in longwall mining operations. Three-phase electrical power is supplied to a rectifier circuit positioned remote from the mining machine to rectify the three-phase electrical power. Rectified electrical power is supplied to the mining machine through cables, whereat the electrical power is inverted by inverters. Power transistors are coupled between the inverters and the respective motors of the mining machine. Positioning the rectifier remote from the mining machine allows the body of the mining machine to be of reduced dimensions.

Abstract: In a drum cutter-loader underground mining machine, wherein the drum is rotatably carried by an arm arranged adjacent to the coal face side of the machine. The arm is pivotally adjusted by a number of pressure cylinders and carried on an axis arranged between a machine body and a housing of a drive motor for the drum. The cylinders are carried by the machine body on a common axis with their piston rods connected to the housing on a common axis, the pivot axes of the arm, cylinders and the piston rod connections being parallelly arranged.

Abstract: A gear rack is made up of rack segments arranged end-to-end supported by and extending along face conveyor for meshing engagement with a gear of a drive to propel a mining machine along a mine face. The teeth of each rack segment extend between longitudinal cheek sections. A thicker one of the cheek sections has a downward extending shoulder at each of opposite ends to engage in a cavity of a bracket and secured therein for limited movement by a fastener pin. A wall section of the bracket extends against a bearing surface formed by a cavity in the underside of the gear tooth at the end portion of the rack segment. The width of the wall section corresponds to the width of the bearing surface.

Abstract: A transformer for use on an underground mining machine, such as a shearer loader. The transformer is cylindrical in shape and contains a central cavity extending therethrough to allow positioning of the transformer about a drive shaft of the motor of the mining machine. A tubular housing surrounds a cylindrical iron core with such housing containing a helically wound coolant duct to allow coolant fluid to flow therethrough.