INSTANTANEOUSLY COMPLETELY COMBUSTIBLE CARTRIDGE CASE MEMBER OF POLYVINYL ACETAL

• US 3,749,023 A
• Filed: 07/16/1971
• Issued: 07/31/1973
• Est. Priority Date: 07/23/1970
• Status: Expired due to Term

• Current Assignee: Hidemichi Kazama, Hisao Yamazaki, Kenji Takahashi, Kunihiko Kawaguchi, Mitsuzo Ono, Nippon Koki Co., Ltd. (NOF Corporation), Yoshimitsu Takeda
• Original Assignee: Hidemichi Kazama, Hisao Yamazaki, Kenji Takahashi, Kunihiko Kawaguchi, Mitsuzo Ono, Nippon Koki Co., Ltd. (NOF Corporation), Yoshimitsu Takeda
• Inventors: Takeda, Yoshimitsu, Nippon Koki Co., Ltd., Kawaguchi, Kunihiko, Takahashi, Kenji, Kazama, Hidemichi, Ono, Mitsuzo, Yamazaki, Hisao
• Primary Examiner(s): Stahl, Robert F.
• Application Number:
  US05/163,287
• Time in Patent Office: 746 Days
• Field of Search: 102/38,43R,43P,39,DIG.1,97
• US Class Current: 102/466
• CPC Class Codes: B29C 44/10 Applying counter-pressure during expanding
• CPC Class Codes: B29C 44/5636 with the addition of heat
• CPC Class Codes: F42B 5/181 consisting of a combustible casing wall and a metal base; Connectors therefor
• CPC Class Codes: F42B 5/188 Manufacturing processes therefor
• CPC Class Codes: F42B 5/30 of plastics , i.e. the cartridge-case tube is of plastics
• CPC Class Codes: Y10S 102/70 Combustilbe cartridge

Abstract

By first radially compression-molding a hollow cylindrical foam of a synthetic resin such as polyvinyl acetal, polyurethane and polystyrene in a mold utilizing a pressurized fluid and then by expanding the compressed foam with heat - after moistening it in a heat-expansion mold, an instantaneously completely combustible cartridge case member is obtained. By the inclusion in the foam of at least one kind of reinforcement filler selected from two groups, i.e., fibers of the said resins and a cloth of said resins, prior to being compressed, the said foam can have an increased strength. By also including a binder of a synthetic resin after compression, further increased strength and hardness of the foam is obtained. The outer surface of the case member may be given an easily combustible thin film and also a damp-proof thin coating on top of the said film. This cartridge case member does not combust spontaneously during handling or during transportation since it combusts at a high temperature. This case member leaves no solid combustion residues at the time of combustion within a firearm. Also, the aforesaid cartridge case members are suitable for manufacture on a mass production basis and the cost of manufacture can be lowered greatly.

Claims

2. An instantaneously and completely combustible cartridge casing according to claim 1, in which said foam contains therein at least one kind of reinforcement filler selected from the group consisting of polyvinyl acetal fibers and polyvinyl acetal cloth.

3. An instantaneously and completely combustible cartridge casing according to claim 1, in which said foam contains polyvinyl acetal fibers mixed therein and also contains a layer of polyvinyl acetal coth embedded therein.

4. An instantaneously and completely combustible cartridge casing according to claim 1, in which said foam contains distributed therein synthetic resin reacted with the residual hydroxyl groups contained in the said polyvinyl acetal foam to form a cross-linked structure.

5. An instantaneously and completely combustible cartridge casing accoridng to claim 4, in which said casing has on its external surface an easily combustible thin film comprising nitrocellulose and a thixotropic agent.

6. An instantaneously and completely combustible cartridge casing according to claim 5, in which said easily combustible thin film is covered with a water-proof thin vinylidene chloride coating.

7. An instantaneously and completely combustible cartridge casing according to claim 1, in which the said casing has a metal bottom member securely bonded to the bottom thereof.