GB1018590A - Mine anchor-line cutter - Google Patents

Abstract

1,018,590. Mine anchor-line cutters. MINE SAFETY APPLIANCES CO. June 8, 1961, No. 20839/61. Heading B7A. A mine anchor-line cutting tool suitable for engagement by like tools in a group of parallel tools extending at right angles to a supporting sweep line comprises a frame 1 provided with a rearwardly extending barrel 3 and an anvil 9 with a portion spaced in front of the barrel, in which barrel a chisel 4 is slidably mounted for movement toward the anvil by an explosive charge 7 disposed within the frame behind the chisel, means being provided for detonating the charge 7 and including a rod 37 normally held in a forward inoperative position by a rigid trigger 45 which moves when engaged by an anchorline in such a direction as to release the rod 37 for movement to its operative detonating position by means of a coil spring 43. The spring 43 encircles the rod 37 and is compressed between the front wall of a recess 38 in the frame 1 and the front end of a plunger 33 to which the rod 37 is fastened. Movement of the rod 37 causes the plunger 33 to enter a passage 30, which is filled with water when the tool is submerged, the water being compressed by the plunger 33 and a piston 31 contained in this passage 30 moved rearwardly to actuate a firing pin 22 by means of a pivoted lever 26. Such a tool is light in weight and several of them can be mounted side by side on a single fin. The leg 10 of the anvil 9 is reduced in thickness at its rear end so that it can extend into a notch ] 1 in the front end of the frame 1 where it is secured by means of a threaded shear pin 12. The anvil 9 is released when it is struck by the chisel 4 but, because its leg 10 is confined between the side of the chisel 4 and the adjoining frame, it is compelled to move straight ahead far enough for it to clear the anvil on the frame of the adjoining tool.