GB1275721A - Signal flare and mine-anchor line cutter utilizing the same - Google Patents

Abstract

1275721 Signal flares for mine anchor-line cutters MINE SAFETY APPLIANCES CO 8 June 1961 20840/61 Heading F3A A signal flare for an explosively operated mine anchor-line cutter is released from the cutter when this is fired and, being buoyant, rises to the surface where gases, generated by a chemical contained in the flare being exposed to water after separation of the flare from the cutter, produce a flame. In one embodiment described (Fig. 2), the flare comprises a cork ball 50 having a diametrical passage in which is mounted a metal tube 51 projecting at one end from the ball which thus floats with this end of the tube 51 pointing downwards. The chemical 52, calcium phosphide which may also contain calcium carbide, is contained in the tube 51 and is kept dry until it is to be used by being tightly sealed in a glass bottle 53. The ball 50 is housed between a spherical recess 55 in the frame of the cutter and a metal cup 57 soldered at 59 to the frame, this joint and the glass bottle 53 both being broken when the chisel of the cutter is driven against the frame to cut through a mine anchor-line. The chemical 52, which becomes wet and generates a gas, does not leave the tube 51 because it is held in a porous fabric bag 63. In another embodiment (Fig. 4), the flare is held in the cavity between a semi-cylindrical recess 67 in the cutter frame and a semi-cylindrical holder 69, the latter being soldered to the frame by a joint 68. The chemical 74 is contained in an open ended metal tube 75 enclosed by a fabric bag 76 and disposed in a glass bottle 73, a cylindrical float 77 occupying the space between the bottle 73 and the bag 76. The float 77 is produced by pouring a predetermined amount of polystyrene beads into the bottle 73 before the tube 75 and bag 76 are inserted, after which the bottle 73 is heated to cause the beads to swell. In a modification of this embodiment, the flare is held to the cutter frame by a metal band, the ends of which are secured by a coil spring which is severed by the chisel when the cutter is fired. In a further embodiment, a flare, similar to the one shown in Fig. 4, is held in an axial chamber inside the chisel by a closure disc soldered to the rear end of the chisel, this joints being broken by the shock of the explosion when the cutter is fired.