| 摘要 |
671,830. Ammunition cartridges. PARIS, C. April 14, 1949. No. 10223/49. Class 9 (i). A cartridge case 4 is closed by a ring 1 of metal or of material known under the term "plastics", the ring having a serrated edge with the tips of the teeth in engagement with the case. The metal ring may have an upturned serrated edge 3 and be of larger diameter than the case. Before inserting the ring 1, a disc 5 of impermeable plastic material is placed on the shot wad 6. This disc may be of cellulose acetate, vinyl chloride, polystyrol, natural or synthetic rubber, poly-isobutylene or similar material. The edge of the disc may be thickened or if a flat disc of uniform thickness is used an annulus 7 is placed on the disc before the closure ring 1. The annulus may be adjacent the wad. The ring may be of cellulose acetate or polyamide of thickness between 0.3 mm. and 1 mm. To insert the closure, the case is placed in a recess of the same diameter in a block of wood or metal and the closure forced into the case, the teeth formed by the serrations thus coming into biting engagement with the inner wall of the cartridge. Closures of thermoplastic material may be forced into position by preheated plungers. Metallic cartridge cases may be internally grooved, roughened or serrated to engage the teeth of the closure ring. |
