GB965413A - Improvements in or relating to primers designed both for electrical and percussion initiation - Google Patents

Abstract

965,413. Primers. DYNAMIT NOBEL A.G. Aug. 18, 1960 [Aug. 22, 1959], No. 28684/60. Heading F3A. A primer, for cartridge, shell or mine fuzes, is optionally capable of electrical ignition, by direct or indirect conduction of an ignition current through the priming composition, or of mechanical ignition. In one embodiment, Fig. 4, an electrically and mechanically sensitive priming composition 1 is pressed into a polepiece 5 and insulated from an outer electrically conductive shell 3 by an insulating layer 4. A booster charge 2 is pressed on to the polepiece 5 and the priming composition 1 and is sealed off by a foil 8. An anvil 11 serves both as an abutment in the case of mechanical ignition and as one of the electrodes for electrical ignition. The other electrode is afforded by the polepiece 5, the priming composition being rendered electrically conducting by the admixture of graphite or other semi-conductive additive. Other embodiments disclose various arrangements of the above-mentioned parts and primers wherein two compositions are used, one being electrically sensitive and the other percussion sensitive. The latter may be housed in a conventional percussion cap. The insulating layer 4 may be provided by chemical coatings whose composition depend on the material of shell 3. For aluminium they may consist of anodically oxidized layers, for steel or zinc of lacquered phosphate and for other metals of stoving enamel.