GB685981A - Improvements in firing mechanism for pyrotechnic devices - Google Patents

Abstract

685,981. Pyrotechnic devices. SCHERMULY PISTOL ROCKET APPARATUS, Ltd. Oct. 31, 1951 [June 12, 1951], No. 13876/51. Class 9(ii) Firing mechanism for pyrotechnic devices such as signal flares comprises a cylindrical member 1 with a forward recess 2 accommodating a detonator holder 21 and communicating with a longitudinal bore 3 in which is a spring-pressed firing pin. In a transverse bore 5 is a pushbutton slide 9 which holds the firing pin 16 in the retracted position. The inner end of the slide has a flange 10 engaging a shoulder 6 in the bore 5 to limit outward movement of the slide, while a pin 13 extending through a bore in the member 1 co-operates with a slot 12 to limit inward movement and prevent rotation of the slide which is held, prior to use of the pyrotechnic device, by passing a split pin 27 through a bore 15 in its outer end. The member 1 has an annular groove 8 into which the casing 25 of the device is cannelured. On removal of the split pin, the slide 9 is pushed inwards bringing an aperture 11 into adignment with the bore 3 and thus releasing the firing pin, the point 20 of which extends into a groove 14 in the slide which rests against a flange 18 of the pin. This flange is cut away at 19 to prevent the formation of an air cushion which would impede movement of the firing pin. The firing mechanism is assembled by first placing the slide in its bore, inserting the transverse pin 13 and then placing the holder 21 containing a" detonator 24 in position. The member 1 is then placed in the casing and the slide caused to move outwards so that the pin 27 can be inserted. An explosive charge is placed in the casing and above it a signal, the casing then being closed by a cap. The firing pin with its spring 28 is then inserted and the bore 3 closed by a retaining screw 29.