Patent GB-282921-A (GB)
Title: Improvements in or relating to coal mining and loading machines
IPC: E21C27/10
Filed: 1926-10-15
Abstract: 282,921. McKinlay, E. S. Oct. 15, 1926. Coal-cutting machines.-A coal mining and loading machine has two or more cutters with radially arranged blades which cut concentric rings in the coal, breaker discs carried by the cutter heads which also carry a central boring and breaking bit, scoops for picking up the broken coal and delivery to troughs and shoots leading to a conveyor. The cutters are arranged to rotate in opposite directions. Reciprocating saws are employed to cut out the coal outside the scope of the rotating cutters. As shown the apparatus comprises a pair of lower rails 2 and upper rails 1 with posts 7, 8, 9 and braces and trusses forming a framework on rollers 3, 4. A motor 14 drives worms 16, 17 gearing with worm wheels 18, 19 respectively transmitting motion to shafts 12, 13. Each shaft carries its corresponding cutter 20, 21 on heads 10, 11 respectively having central boring bits 24 with coned surfaces 25 for breaking down the central ring of coal. Discs 26, 27 also carried by the cutter heads enter the concentric channels cut and by means of their wedge shaped outer surfaces brea.k down the rings of coal. The cutters 20, 21 are provided with serrated edges and are each of a form corresponding to an arc struck from the axis of the cutter head. The broken coal falls down and is lifted by scoops 22, carried by the cutter heads. The scoops are suitably shaped to direct the coal at the uppermost position to troughs underneath, which lead to shoots 32 and from thence to a belt conveyor 34, which also receives coal from a lower upwardly inclined shoot 37 as the machine is forced forwardly. Means are adopted to force aside the coal lying at the bottom so as not to foul the roller 3, 4. The uncut coal between the two circular zones dealt with by the rotary cutters is acted on by pairs of saws, an upper pair 41, 42 being carried by a framework 45 which reciprocates under the action of eccentrics keyed to the shafts 12, 13, the framework being slidingly held by dips and guided by rollers such as 52, 53. The conveyer belt, which passes round a series of idler rollers, is driven by a roller 63 from the cutter shaft by worm gearing 74, 73, and is forced against the driving pulley by a spring pressed pressure roller 69 the pressure of which can be adjusted by a nut 72. By loosening the tension of the springs 70 to a suitable amount the speed of the conveyor belt may be reduced or entirely stopped. To keep the machine up to its work, claw bars 76 diverge rearwardly and are pivoted to engage the walls of the mine. The claw bars 76 are coupled to a plunger in an hydraulic cylinder 79. The pressure of the cylinder is transmitted directly to the cutters and not through the frame of the machine. In operation, when the machine is placed in position the claw bars 76 are pushed forwardly until the piston is at the beginning of its stroke m the cylinder 79, pressure is admitted to the cylinder and the anchoring of the machine by the bars 76 forces the cutters against the coal face so that when the circuit of the motor is closed the cutters commence operation, the rings are cut, and the coal broken down picked up by the scoop and taken by the conveyor to a position for loading trucks. The machine advances automatically until the piston is at the bottom of its stroke in the hydraulic cylinder whereupon the anchorage claws are reengaged in a new position. In order to transfer the coal to a loading position above the trucks an extension of the conveyor system is provided and a train of cars may be progressively filled and cable-drawn to the entry of the mine. The extension of the conveyor includes a framework and a belt with its rollers carried thereby. The belt is laced to the main belt and can be turned to any angular position with its framework by unlacing the belt and detaching the auxiliary framework from the main framework on which it is capable of pivoting to the required angular position. The extension may be moved from the main belt or independently. The various types of rollers are described for the belt to facilitate feeding the coal. In Fig. 18 is seen the cutter heads 10, 11 which rotate in opposite direction and in this case cooperate with a chain slot cutter 130 driven by bevel gearing 135 from the cutter shaft. A conveyor belt 137 in this case is arranged beneath the ledge produced by the slot cutter so that the coal is received directly upon the conveyor. In another construction a pair of chain driven slot cutters are mounted to be capable of being swung out step by step from an inoperative position. A piping system serves to exhaust the coal dust or gas from and to supply fluid to the cutting position and a pump or fan may be also introduced. The cutter head may be curved substantially to the shape of a letter S or to an ogee curve to provide the cutter blades in offset relation to one another. In Fig. 25 is shown a construction of cutter head 153 in the form of a hollow bar with pairs of tubes 154, 155. The tubes 155 carry wire or other appropriate material the extremities of which bite into the coal and the tubes 154 are left open for the fluid or for connection to a suction device. The scoop on the cutter heads may have an adjustable wall for controlling the amount of coal fed to the conveyer. Scraper blades may be added to the cutter head to sweep the coal to the conveyer. The breaking down cone at the centre of the cutter head may be replaced by a device with an interrupted conical surface. The discs which break down the coal may be adjustable in position. The wire end cutters may be encased in soft metal which is adapted to wear down thereby constantly exposing the ends of the wire for the cutting operation. The machine may be mounted on plates or shoes where the ground is heavy.