US3516357A - Ammunition cartridge - Google Patents

Description

June 23, 1970 G. E. HENDRICKS AMMUNITION CARTRIDGE Filed Jan. 25. 19

INVEN'IOR. GROVE/P E. HE/VDR/CKS A 7' TO/QNE) United States Patent US. Cl. 102-45 2 Claims ABSTRACT OF THE DISCLOSURE An ammunition cartridge, including a cartridge casing having a base, a projectile and a powder charge contained within the casing. A primer is positioned within the base of the casing and includes an anvil, primer cover, and a preformed primer powder unit. The anvil includes a substantially cylindrical core and an integral concentric cylindrical wall spaced from the core to define a longitudinal annular groove. The anvil core has a longitudinal bore therein. The primer cover has an end wall and a substantially cylindrical wall. The preformed primer unit includes a thin walled envelope confining a powder charge and is positioned within the primer cover adjacent the end wall thereof. The primer cover encircles part of the anvil core and is seated within the annular groove in the anvil with its end wall spaced from the anvil.

BACKGROUND OF THE INVENTION This invention relates to ammunition cartridges.

Primers heretofore used in ammunition cartridges were assembled with the primer powder being inserted into the primer cup or the cartridge casing in an inert or muddy state. After final assembly of the cartridge, the primer was baked for a predetermined period of time and at a predetermined temperature so as to transform its powder into an explosive mixture. The firing hole at the forward end of the primer was then sealed by a lacquer or paper sealing material to prevent the primer powder from being contaminated or subjected to moisture.

SUMMARY OF THE INVENTION This invention relates to an improved ammunition cartridge in which the primer charge is enclosed in a thin walled envelope with said envelope being positioned within the base of the cartridge casing so that the primer powder charge is susceptible to detonation by a percussive force directed toward the casing base.

In this invention the primer powder charge is formed into a prefabricated sealed wafer which is inserted into the circumferential margin of the base of a rimfire ammunition cartridge or into the primer assembly of a centerfire ammunition cartridge and which needs no application of heat after insertion to render it usable. The primer charge, by being sealed in a thin walled envelope, is substantially free of contamination and moisture, thus eliminating the need for sealing the fire hole of the primer assembly. In addition, the prefabricated primer wafer may be readily handled, thereby permitting the primer assembly to be assembled easily.

Accordingly, it is an object of this invention to provide an ammunition cartridge that can be readily and eco nomically assembled.

It is a further object of this invention to provide an ammunition cartridge which can be safely handled by the user and which may be reliably detonated by the hammer or firing pin force of a firearm.

It is a further object of this invention to provide an ammunition cartridge of economical and simplified construction.

Other objects of this invention will become apparent upon a reading of the inventions description.

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BRIEF DESCRIPTION OF THE DRAWINGS The preferred embodiments of the invention have been chosen for the purposes of illustration and description wherein:

FIG. 1 is a longitudinal sectional view of a rimfire ammunition cartridge.

FIG. 2 is a side elevation of the primer utilized in the ammunition cartridge of FIG. 1, with part broken away.

FIG. 3 is a longitudinal sectional view of a centerfire ammunition cartridge.

FIG. 4 is a cross sectional view of the prefabricated primer wafer utilized in the primer assembly of the ammunition cartridge of FIG. 3.

FIG. 5 is a side elevation of the prefabricated primer wafer utilized in the primer assembly of the ammunition cartridge of FIG. 3.

FIG. 6 is a longitudinal sectional view of a primer assembly utilized in the centerfire ammunition cartridge of this invention.

FIG. 7 is a longitudinal sectional view of a modifica tion of the primer assembly of FIG. 6.

FIG. 8 is a right end view of the primer assembly of FIG. 7.

FIG. 9 is a longitudinal sectional view of another embodiment of a primer assembly used in the centerfire ammunition of this invention.

FIG. 10 is a longitudinal sectional view of a modifica tion of the primer assembly of FIG. 9.

FIG. 11 is a longitudinal sectional view of another modification of the primer assembly of FIG. 9.

FIG. 12 is a longitudinal sectional view of another embodiment of a centerfire ammunition cartridge.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The preferred embodiments illustrated are not intended to be exhausted or to limit the invention to the precise forms disclosed. They are chosen and described in order to best explain the principles of the invention and its application and practical use to thereby enable others skilled in the art to best utilize the invention.

This invention pertains to ammunition cartridges of which two general types are illustrated by FIGS. 1 and 3.

FIG. 1 illustrates a rimfire ammunition cartridge which comprises a cartridge shell 22 having an annular base flange 24, a primer 11, a powder charge 26 and a projectile head 28. The powder 12 of primer 11 may be of the type commonly used in toy cap guns and is arranged in a body of annular or ring shape as shown in FIG. 2 and enclosed in an envelope 14. Envelope 14 is preferably formed from thin sheets of paper or other breakable and combustible material having suffirient rigidity to retain its wafer-like shape after being inserted into a cartridge. To retain the powder 12 in its annular shape and to prevent its leakage and contamination, envelope 14 is preferably sealed about the outer and inner circumferential peripheries of the powder ring 12 and sized to closely conform to the peripheries of the powder ring thereby forming thin circumferential margins 16 and 18.

Primer 11 is inserted into cartridge shell 22 to abut base 13, with outer margin 16 and preferably a portion of the powder 12 fitting into an interior annular groove 25 formed between base flange 24 and cylindrical wall 27 of shell 22. The powder charge 26 is then placed in the cartridge shell 22 adjacent to or in contact with the primer 11 and there confined by projectile head 28 whose inner part fits in the open end part of the cartridge shell 22 and is preferably fixedly mounted therein by a crimp 23.

FIG. 3 illustrates a centerfire ammunition cartridge which comprises a cartridge casing 2, primer assembly 4, wad and shot carrier 6, projectile powder charge 8 and shot charge 9. Primer assembly 4 is mounted in a concentric aperture 7 in the base of cartridge casing 2 and, although illustrated in FIG. 3 as the primer assembly shown in detail in FIG. 10, can assume any of the various primer assembly embodiments illustrated by FIGS. 6, 7, 9, 10 and 11.

The primer powder 30 used in each of the primer assemblies illustrated in FIGS. 6, 7, 9, 10 and 11 may be of the type commonly used in toy cap guns and is mounded as shown in FIGS. 4 and 5 and enclosed in an envelope 29 so as to form a primer wafer 10. Envelope 29 is preferably formed from thin sheets of paper or other breakable and consumable material having suflicient rigidity to retain its wafer-like shape after being inserted into the primer assembly. To retain the powder 30 in its mounded shape and to prevent its leakage and contamination, envelope 29 is preferably sealed about the outer circumferential periphery of the powder mound and is generally sized to conform to the outer powder mound periphery so as to form an annular margin 32.

The primer assembly of FIG. 6 includes a deep walled battery cup 34 having an aperture 36 preferably concentrically located in its base and a flanged rim 35. A cylindrical anvil 38 with an axial bore 40 therethrough is press fit into battery cap 34. Anvil 38 is circumferentially shouldered to provide a seat for the edge of a cupshaped primer cover 42. The primer wafer 10 is inserted into primer cover 42 and positioned against its base 43. Wafer 10 may be held against base 43 by an adhesive or may have a diameter equal to or greater than the inner diameter of the primer cover so that it may have a press fit at its periphery within the primer cover 42. The primer cover 42 with wafer 10 positioned therein is mounted over anvil 38 and press fit into the battery cup 34 with the edge of cover 42 resting against shoulder 44 of the anvil 38. The depth of primer cover 42 and the longitudinal location of shoulder 44 to anvil 38 is such that, with the edge of the primer cover seating against shoulder 44, the primer wafer 10 lightly contacts anvil 38 with the mounded powder 30 partially overlying bore 40.

A modification of the primer assembly of FIG. 6 is shown in FIG. 7 in which the anvil 46 is in the form of a plate. Anvil plate 46 preferably has a thickness which is less than the diameter of aperture 36 and contains a notch 37 in its end which is positioned adjacent aperture 36.

The primer assembly of FIG. 9 includes a deep walled cup shaped primer cover 50. A primer wafer 10 is inserted into the primer cover 50 and positioned against its base 51. The wafer 10 is held against the base 51 by any one of the means hereinbefore described. A cylindrical anvil 52 having a shouldered portion 14 is press fit into the primer cover 50 with the shoulder portion 54 seating upon the edge 56 of primer cover 50. Anvil 52 has an axial bore 58 therein which may be sealed at its exposed end by thin membrane 60. Membrane 60 is preferably formed as an integral portion of anvil 52 and will rupture at time of firing. The depth of primer cover 50 and the longitudinal location of anvil shoulder portion 54 are such that, with the edge of the primer cover seating against the anvil shoulder portion, the primer wafer 10 is slightly spaced from anvil 52 with the mounded powder partially overlying bore 58.

A modification of the primer assembly of FIG. 9 is shown in FIG. 10 in which primer cover 50 has an exterior flange 64 formed about its base.

Another modification of the primer assembly of FIG. 9 is shown in FIG. 11 in which anvil 90 is of a cylindrical configuration having axial bore 92 therein. Anvil 90 includes a core portion 93 and a spaced concentric integral anular wall 96 defining a narrow deep annular groove 94. Snugly seated within annular groove 94 is a cylindrical wall 97 of cup-shaped primer cover 98. A

primer wafer 10 positioned in cover 98 bears against its base. The respective depths of primer cover 98 and annular groove 94 are such that, with the edge of the primer cover wall 98 seated against the bottom of the annular groove 94, the primer Wafer 10 is slightly spaced from anvil with its mounded powder 30 partially overlying bore 92. The end portion of anvil side wall 96 may terminate in an outwardly projecting annular flat flange which is preferably flush with the base of the primer cover 98 or which may extend slightly beyond the base of primer cover 98. Anvil bore 92 may be sealed at its exposed end by thin membrane 102 which preferably constitutes an integral part of anvil 90 and which will rupture at time of firing.

The anvils utilized in the aforedescribed cartridges may be of either metal or hard plastic. The advantage of using a plastic anvil is that it permits the use of thinner material for the primer cover since the plastic will slightly deform under the hammer action of the firing pin rather than provide an unyielding part which could perforate the cover.

The slight space or air gap between the primer wafer and the anvil of the primer assembly is an optional modification. The advantage of such an air gap is that it provides a margin of safety against detonation of the primer powder during assembly of the primer and subsequent handling by the ammunition cartridge user. Of course the air gap, when incorporated, is very slight and will not prevent the primer powder from forceably contacting the anvil upon deformation or movement of the primer cover under the force exerted by the firing pin of a gun. Also the membrane sealing the anvil bore or firing part is optional. Its presence or absence depends in part upon the desirability of sealing the anvil bore to the cartridge powder charge, and where used it will be readily ruptured upon firing.

A primer assembly of similar configuration to that illustrated in FIG. 9 may be sized to fit within the end portion of a cylindrical ammunition cartridge as shown in FIG. 12. This primer assembly comprises an anvil 70, a cup-shaped primer cover 76 and a primer wafer 10 and is press fit into the end portion of shell casing 78. The outer surface 79 of an outturned annular casing flange 80 formed on casing 78 is preferably flush with the exposed surface of base 91 of the primer cover 76. The anvil 70 has an axial bore 72 which preferably flares at its inner end to form a portion of the powder charge chamber 73. Primer wafer 10 lightly touches anvil 70 overlying and preferably sealing the end of bore 72. Confined within chamber 73 by a wadding 82 is a powder charge 74. Shot members 84 are contained in the casing 78 outwardly of wadding 82 and are confined within shell casing 78 by an end wall 86 formed by inwardly bending and crimping the end portion of casing 78.

What I claim is:

1. In an ammunition cartridge including a cartridge casing having a base, a projectile and a powder charge contained within said casing, a primer positioned within the base of said casing and includng an anvil, primer cover, and a preformed primer powder unit, said anvil having a substantially cylindrical core and an integral concentric cylindrical wall spaced from said core to define a longitudinal annular groove, said core having a longitudinal bore therein, said primer cover having an end wall and a substantially cylindrical wall, said preformed primer unit including a thin-walled envelope confining a primer powder charge, said preformed primer unit being positioned within said primer cover adjacent its end wall, said primer cover encircling a part of said anvil core and seated within said angular groove and having its end wall spaced from said anvil to confine said preformed powder unit with its powder charge substantially aligned with said anvil core bore and detonatable upon application of percussive force to said primer cover.

2. The ammunition cartridge of claim 1, wherein said upon firing.

Re 4,076 Re 7,394

anvil includes an integral membrane which encloses one end of said longitudinal bore and which is rupturable References Cited UNITED STATES PATENTS Moffatt 102-45 Hotchkiss 102-45 Van Vechten 102-45 Mills 102-38 X Quinlan et a1 10243 10 6 3,195,463 7/1965 Foote et al. 102-86.5 3,236,181 2/1966 Woodring et a1. 102-45 3,352,240 11/1967 Eckstein 102-45 FOREIGN PATENTS 1,429,346 l/1966 France.

BENJAMIN A. BORCHELT, Primary Examiner S. C. BENTLEY, Assistant Examiner

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