GB1376932A - Apparatus for steering a longwall mineral mining machine - Google Patents

Abstract

1376932 Mineral mining machines COAL INDUSTRY (PATENTS) Ltd 13 Oct 1972 [12 Nov 1971] 52691/71 Heading E1F [Also in Division G3] A mineral mining machine 1, having a cutter head 6, is provided with a probe 10 for sensing the rock boundary of a seam which is mounted on that part of the machine carrying the cutter head by means of an arm 11 biassed toward the seam; the machine being steered in response to signals from the probe and from a means which senses the position of the probe relative to the machine. The arrangement shown has a machine 1 mounted on an under frame 4 which has guides 5 (only one shown) engaging the upper flanges of conveyor pans 3 and the machine is steerable by hydraulic rams which cause relative pivoting between upper and lower portions of the under frame to change the cutting horizon. The probe 10 is a combined radiation emitter/detector and is mounted on an arm 11 which is in the form of a hydraulic ram; the ram including a potentiometer arrangement (20, Fig. 3, not shown) producing an output dependent on the rams extension. A control means (Fig. 3 not shown) operates the steering rams and receives, in addition to signals from the probe and arm, a reference signal (28) from a potentiometer preset in accordance with the desired seam thickness, and a signal from an inclinometer (25) which senses the inclination of the seam floor. The inclinometer is designed to produce no signal as long as the inclination of the machine remains within preset limits but outside these limits to produce a signal having a much greater effect than the other signals. The probe is shown mounted directly behind the cutting head but can be mounted over the axis of rotation of the head (Figs. 4, 5 not shown). The arm 11, instead of having a variable length as shown, can have a fixed length and be pivotally mounted to the machine with its pivotal movement providing signals of the probe's movement.