Patent GB-761716-A (GB)
Title: Improvements in or relating to pyrotechnic devices for giving visual signals
IPC: F42C14/02
Filed: 1954-08-13
Abstract: 761,716. Pyrotechnic signalling devices. IWATA, Y. Aug. 13, 1954, No. 23606/54. Class 9 (2). A pyrotechnic device for giving visual signals has a cylindrical body 1 closed at one end by an inflammable disc 3 and at the other by an apertured disc 7 in which is seated a tube 5 extending through the body 1 to a second apertured disc 7a which divides the body into two chambers 4, B. The annular chamber B around the tube 5 is filled with inflammable material 2 ignited by means within chamber 4. A pistol grip 13 fitted in the body 1 to abut the flange 7 contains a trigger mechanism 15, 21 connected by a rod 17 extending through the composition 2 to the ignition means A. Within the chamber 4 is a pivoted plate 20 bearing against a spring 10 and apertured to receive the end of a rod 6, which extends through the tube 5. On the rod 6 and resting against the plate 20 is a holder 9 coated with an ignition composition and connected to a fuze cord 22. The composition may be sulphur or antimony sulphide with potassium chlorate and powdered glass bound together with glue. The ignition means A is aligned with the rod 6 and comprises a spring 11 surrounding a member 12 coated with an abrasive agent such as red phosphorus and powdered glass bound together with glue. Before using the device, which may be held in the hand or mounted on a support by means of a spike 29, the trigger 21 is moved to the operative position. Then by depressing the trigger, the rod 17 is pulled downwardly, the pull being transmitted through a lever to the plate 20 to compress the spring 10. On release of the trigger, the spring 10 drives the plate 20 upwardly and thus drives the holder 9 into the ignition means A. The spark produced by the abrasive surface rubbing against the holder 9 ignites the fuze cord 22, which in turn ignites the flash composition 2. The disc 3 is also ignited and destroyed. In a modification, the pistol grip is replaced by a rotatable cap 30 provided with an opening 31 covered with a waterproof seal. When using the device, the cap is rotated until the opening 31 is aligned with a similar opening 27 in the body 1 and the seals of both openings are then destroyed to give access to a trigger 33. By depressing the trigger, the rod 17 is displaced and the holder 9 rubbed against an abrasive surface 12 within the tube 5. Thus inflammable material in the chamber A is ignited and this ignites the tube 5 and the flash powder 2. In another embodiment, Fig. 4, a percussion cap on the inner surface of the disc 3 is adapted to be struck by a rod 35 and thereby ignite a composition 71 in the chamber 4 to initiate the flash charge 2. The rod 35 has a cranked arm 38a extending through an L-shaped opening in the body 1. By moving the arm 38a out of the short branch of the L, the rod is released and a spring 34 then drives the rod against the cap. Triggeroperated devices are also described in which the connection between the trigger and the ignition chamber is housed externally of the body 1. The spark to ignite the fuze cord may be produced by friction between a toothed sector and a pyrophoric stone or by a resistance wire'embedded in ignition material, the wire being connected to an electric battery and the circuit completed by depressing a trigger.