Mining machine conveyor and apparatus for controlling the tension thereon

Abstract

A mining machine having a body portion mounted on propelling tracks includes an endless conveyor mechanism that extends longitudinally on the body portion. The conveyor mechanism is rotatably supported at the front and rear end portions thereof by roller assemblies. The rear roller assembly is longitudinally movable and driven by a hydraulically operated motor to advance the conveyor mechanism from a receiving end portion to a discharging end portion. The discharging end portion is supported for lateral swinging movement relative to the main conveyor portion. Hydraulically operated take-up devices are connected to the rear roller assembly and maintain a preselected tension on the conveyor to prevent slack developing therein. Each take-up device includes a cylinder with a rod having a shoulder portion of a preselected differential area against which fluid pressure is applied to extend the rod from the cylinder. The fluid pressure in each cylinder is supplied from the hydraulic circuitry of the conveyor drive motor. Thus, the cylinders are load sensitive so that an increase in the load on the conveyor drive motor, as when the conveyor is swung laterally, results in an increase in force upon the rear roller assembly to take-up the slack in the conveyor. This avoids excessive tension on the conveyor when the conveyor portions are aligned. Only that force required to prevent slack from developing is applied to the conveyor by the take-up devices.