US3771454A

US3771454A - Primer

Info

Publication number: US3771454A
Application number: US00293192A
Authority: US
Inventors: W White; T Ciccone
Original assignee: United States Department of the Army
Current assignee: United States Department of the Army
Priority date: 1972-09-28
Filing date: 1972-09-28
Publication date: 1973-11-13
Anticipated expiration: 1990-11-13

Abstract

A percussion primer for small caliber ammunition in which the pellet loading can be accomplished by disc punching machines to increase primer production rates. A thin sheet of plastic material is seated in the base portion of the primer cup and has an upper surface coated with an abrasive material, preferably antimony sulfide. A plastic disc of igniter material overlies the abrasive material, and a plastic disc of high energy combustible material overlies the igniter disc. A protective foil overlies the combustible disc, and an anvil is seated in the cup and pressed against the foil.

Description

United States Patent [1 1 White et al.

[ Nov. 13, 1973 [22] Filed:

[ PRIMER [75 Inventors: Wilmer White, Haddonfield, N.J.;

Thomas Q. Ciccone, Cornwells, Pa.

[73] Assignee: The United States of America as represented by the Secretary of the my Sept. 28, 1972 [21] Appl. No.: 293,192

[52] US. Cl. 102/45 [51] Int. Cl. F42!) 19/10 [58] Field of Search 102/45, 38, 86.5

[56] I References Cited UNITED STATES PATENTS 2,021,498 11/1935 Campbell 102/45 3,320,887 5/1967 Quinlan et al. 102/45 Primary Examiner-Robert F. Stahl Att0rney-Harry M. Saragovitz et a1.

[57] ABSTRACT 4 Claims, 1 DrawingFigure PATENTEB NOV 1 3 I975 PRIMER This invention described herein may be manufactured, used, and licensed by or for the Government for governmental purposes without the payment to us of any royalty thereon.

'This invention relates to primers, and more particularly, to percussion primers for small caliber ammunition.

l-leretofore, a loosely bound mix of chemical ingredients for a primer pellet were mixed and pelleted by manually rubbing the mix over perforated plates of predetermined dimensions prior to loading with a knock out plate.

It is an object of the invention to provide a primer having a laminated plastic pellet.

Another object of the invention is to provide such a primer that enables a high volume production rate to be obtained with product uniformity.

These and other objects, features and advantages will become more apparent from the following description and accompanying drawing which is a sectional view of a percussion primer embodying the principles of the invention.

The substantially cylindrical brass cup 11 has a closed base portion 12 of predetermined thickness to accommodate penetration by a firing pin of a munition firing mechanism (not shown). The laminated primer pellet, shown generally at 13, preferably includes a thin sheet 14 of plastic material having a lower or bottom surface that seats against the cup base portion 12 as well as an upper surface that is coated with an abrasive material 15. A plastic disc 16 of igniter material overlies the abrasive coating 15, and a plastic disc 17 of high energy combustible material overlies the igniter disc 16. A waterproof seal of protective foil 18 overlies the combustible disc 17, and the conically shaped brass anvil 19 is press-fitted within the sidewalls of cup 11 with the anvil nose portion 20 pressed against the foil 18.

Preferably, the abrasive coated thin plastic sheet 14 comprises a thin layer of cellulose nitrate base sealing compound having a bottom surface that adhers to the cup base 12 and an upper surface which is coated with antimony sulfide 15. The igniter plastic material 16 is prepared in sheet form and consists of a polymerized mixture of nitrocellulose, acetone, lead styphnate and tetracene. The highly combustible plastic material 17 is prepared in sheet form and consists of a polymerized fuel and oxidizer mixture of nitrocellulose, acetone and barium nitrate. An appropriate disc punching machine punches the desired igniter plastic disc 16 of predetermined size from the igniter sheet and the disc 16 is allowed to fall directly into its cup 11 upon the abrasive coated sheet 14. Similar punching; technique is utilized for loading one or more highly combustible discs 17 from its sheet, prior to assembling a punched aluminum protective foil 18 which also can be of wax paper or tin material. After being loaded, the primer cup is drained and dried prior to insertion of anvil 19. Upon drying of the primer, substantially all of the acetone will have been evaporated.

Various modifications, changes or alterations may be resorted to without departing from the scope of the invention as defined in the appended claims.

We claim:

1. A percussion primer for small caliber ammunition, comprising a substantially cylindrical cup member having a closed base portion,

a thin sheet of plastic material having a bottom surface seated against said base portion and an upper surface coated with an abrasive material,

a plastic disc of igniter material overlying said abrasive material,

a plastic discof high energy combustible material overlying said igniter disc,

a protective foil overlying said combustible disc, and

an anvil seated in said cup member and pressed against said foil.

2. The structure in accordance with claim 1 wherein said abrasive material is antimony sulfide.

3. The structure of claim 2 wherein said igniter material includes nitrocellulose, lead styphnate and tetracene, and said combustible disc includes nitrocellulose and barium nitrate.

4. The structure of claim 3 wherein said foil is a material selected from the group including aluminum, tin

and wax paper.

Claims

2. The structure in accordance with claim 1 wherein said abrasive material is antimony sulfide.
3. The structure of claim 2 wherein said igniter material includes nitrocellulose, lead styphnate and tetracene, and said combustible disc includes nitrocellulose and barium nitrate.
4. The structure of claim 3 wherein said foil is a material selected from the group including aluminum, tin and wax paper.