US3732820A

US3732820A - Ball anvil primer

Info

Publication number: US3732820A
Application number: US00157299A
Authority: US
Inventors: G Hendricks
Original assignee: Individual
Current assignee: Individual
Priority date: 1971-06-28
Filing date: 1971-06-28
Publication date: 1973-05-15
Anticipated expiration: 1990-05-15

Abstract

A primer including a support disposed within a cavity. The support carries a ball-like anvil over which is disposed an inverted cup-shaped primer cover. A primer powder charge is positioned between the primer cover and anvil and is detonatable upon the application of a percussive force to the primer cover.

Description

United States Patent 1 Hendricks May 15, 1973 54] BALL ANVIL PRIMER 120,196 l0/l87l Hobbs et al. ..102 45 [76] Inventor: Grover E. nendricksrzsss N'E 1,310,844 7 1919 Semple .l02/86.5

. 19th Street, Pompano Beach, FOREIGN PATENTS ORAPPLICATIONS 661,306 5/1938 Germany ..102 45 22 Filed: June 28, 1971 708,996 6/1941 Germany ..102 45 [21] Appl' Noi: 151399 Primary ExaminerRobert F. Stahl Related US. Application Data [63] Continuation-impart of Ser. No. 29,787, April 20,

1970, abandoned.

[52] US. Cl ..'...l02/45 [51] Int. Cl ..F42b 5/36 [58] Field of Search ..102/38, 44, 45, 86.5

[56] References Cited 'UNITED STATES PATENTS 513,997 2/1894 Gatling ..102/45 Attorney Eugene C. Knoblock et al.

[57] ABSTRACT A primer including a support disposed within a cavity. The support carries a ball-like anvil over which is disposed an inverted cup-shaped primer cover. A primer powder charge is positioned between the primen-cover and anvil and is detonatable upon the application of a percussive force to the primer cover.

10 Claims, 9 Drawing Figures PATENTED 3. 732,820

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doned.

BALL ANVIL PRIMER CROSS-REFERENCE TO RELATED APPLICATION This application is a continuation-in-part of my application Ser. No. 29,787, filed Apr. 20, 1970, now aban- SUMMARY OF THE INVENTION This invention relates generally to ammunition cartridges and has particular application to the construction of the primer for the cartridge.

The primer of this invention includes a hole-defining part which may be in the form of a separately constructed battery cup or which may be formed integrally with the cartridge casing end wall or in the base wad of a shot gun shell. The hole-defining part of the primer includes a support means. A ball-shaped anvil is supported by said support means. An inverted cup-shaped primer cover fits within the hole-defining part of the primer and is positioned with its end wall spaced from the anvil. A primer powder charge is disposed between the primer cover end wall and anvil and is detonatable upon the application of a percussive force to the primer cover.

This invention provides the sportsman with an economical, dependable ammunition cartridge and will be of particular benefit to the user of hand-loaded shot gun shells. The primer cover will preferably carry the primer powder charge so as to enable the components of the primer to be assembled in a simple and rapid manner.

Accordingly, it is an object of this invention to provide a shot shell casing having a part of the primer assembly formed integrally therewith.

It is another object of this invention to provide a primer for an ammunition cartridge which is of economical manufacture.

Another object of this invention is to provide a primer for an ammunition cartridge which can be assembled by the head loader in a rapid manner.

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

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal sectional view of an ammunition cartridge having a casing and primer constructed in accordance with this invention.

FIG. 2 is a longitudinal sectional view of the casing of the cartridge illustrated in FIG. 1 showing parts of the primer separated therefrom.

FIG. 3 is an end view of the cartridge casing as viewed in the direction of line 33 of FIG. 2.

FIG. 4 is a fragmentary sectional view of the cartridge casing taken along line 4--4 of FIG. 3.

FIG. 5 is a longitudinal sectional view ofan ammunition cartridge having a primer constructed in accor dance with this invention.

FIG. 6 is an enlarged sectional view of the encircled portion of FIG. 5.

FIG. 7 is an enlarged exploded view of the primer illustrated in FIG. 5.

FIG. 8 is an end view of the primer battery cup as seen from line 88 in FIG. 7.

FIG. 9 is a sectional view taken along line 99 of FIG. 8.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The preferred embodiments "illustrated are not intended to be exhaustive 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 utilize the invention.

FIGS. 1-4 are illustrative of an ammunition cartridge having a casing 10 which is preferably formed from a plastic material, such as polyethylene or polypropolene. Casing 10 includes a tubular portion 12 and an integrally connected end or base portion 14. A wad 16 is disposed within tubular portion 12 and cooperates with base portion 14 to define a powder chamber 17. Wad 16 may be constructed as disclosed in my U.S. Pat. NO. 3,487,779 and carries shot 18. The forward margin 20 of casing tubular portion 12 is folded inwardly to form an end wall to retain shot 18 within the ammunition cartridge. Powder chamber 17 contains a powder charge 22. The cartridge thus far described is of a construction well known in the art.

In this embodiment of my invention casing base portion 14 includes an outer face 24 and has a primer cavity 26 formed therein. Primer cavity 26 opens at casing outer face 24 and is defined by a side wall 25, which preferably includes an inner cylindrical surface 27, and an end wall 28. End wall 28 defines an integral seat or support means which receives a spherical member or anvil 30 and which preferably comprises a plurality of web parts 32. Web parts 32 extend radially outwardly from the longitudinal axis of cavity 26 and define interstices 34 therebetween. The end edge 36 of each web part 32 is beveled with that part of the edge which is adjacent cavity side wall 25 being nearer casing outer face 24 than that part of the edge which is adjacent the longitudinal axis of cavity 26. End wall 28 preferably includes at least three web parts 32 with the convergent end edges 36 thereof cooperating to define a seat into which anvil 30 is positioned. The cavity end wall parts 38 at the bases of the interstices 34 are of a thin-walled, membrane construction.

This invention further includes acup-shaped primer cover 40. Primer cover 40 includes a side wall 42, which is preferably cylindrical, and an end wall 44 and is inserted into cavity 26 with its side wall 42 encircling anvil 30 and its end wall 44 spaced from the anvil. The outer face of cover end wall 44 and outer face 24 of the shell casing are preferably substantially coplanar. A primer powder charge 46 is located between cover end wall 44 and anvil 30. The primer powder charge 46 may consist of an explosive mixture which has been baked onto the inner face of cover end wall 44 or a prefabricated sealed wafer like that disclosed in US. Pat. Nos. 87,735 and 3,5l6,357 which abuts end wall 44. The primer powder charge 46 preferably makes light contact with anvil 30.

Anvil 30 need not be perfectly spherical and in fact can be of a football shape. Anvil 30 may be formed of a metal or hard plastic which is forceably contacted by primer powder charge 46 when primer cover 40 is struck by the firing pin of a gun. The support means in primer cavity end wall 28 is structured to resist forward movement of the anvil 30 relative tothe casing so as to allow primer powder charge 46 to make forceable detonating contact with the anvil. Detonation of the primer powder charge causes the rupturing of membrane parts 38 of cavity end wall 28 and permits the fire from the primer powder charge to travel through interstices 34 and into cartridge powder chamber 17, thereby causing the detonation of powder charge 22 therein. It is to be understood that membrane parts 38 are optional and that cavity end wall 28 may optionally define openings at the bases of the interstices 34.

Each end wall web part 32 may be slotted at 50 so as to accommodate the marginal edge portion of primer cover side wall 42, as shown in FIG. 1. The leading edge 52 of primer cover 40 is preferably slightly spaced from the base of each web part slot 50 so as to assure movement of the primer cover relative to casing base portion 14 and forceful contact between the primer powder charge 46 and anvil 30 as a percussive force is applied to the primer cover. The primer cover 40 is retained within primer cavity 26 by frictional contact of its side wall 42 with either cavity side wall. 25 or web parts 32 or with both the cavity side wall and web parts. It is also contemplated that the support means of cavity end wall 28 can include anvil retainer means, such as inturned lips which grasp the anvil, for causing the anvil to be firmly held within the support means by the end wall itself.

FIGS. -9 are illustrative of an ammunition cartridge having the primer of this invention formed entirely of a separate construction instead of having a part integrally formed as a portion of the cartridge casing as shown in FIGS. l-4. This cartridge is of a similar construction as the cartridge in FIGS. l-4, having a casing 10, a wad 16 which cooperates with the base portion 14' of the casing to define a powder chamber 17, shot 18, and a powder charge 22.

Base portion 14 of the casing has a central annular bore 60 which extends from theouter face 24 of the base portion to powder chamber 17. The inner margin of bore 60 is defined by an inturned annular lip 62. The primer includes a battery cup 64 having an annular side wall 66. The inner end 67 of cup side wall 66 preferably has a reduced outside dimension so as to define a shoulder 68 which abuts lip 62 of the base portion as the battery cup 64 is pressed into bore 60 in a frictional fit. The outer end of said wall 66 can have a reduced inside dimension at 69 and may terminate in an outturned annular lip 70. Lip 70 of the side wall is received within an annular recess 71 formed in outer face 24 of the base portion at bore 60. A post 72 is coaxially positioned within cup 64, extending from the inner end 67 of side wall 66 to a location inwardly spaced from the outer end of the side wall. Post 72 is supported within bore 60 by a plurality of spaced, radially extending web parts 74 which are integrally connected between the post and side wall 66 at its inner end 67. The interstices 76 between web parts 74 may be open or, preferably, are closed by rupturable thin end wall parts or membranes 78. End face 80 of post 72 is of a concave configuration. In other constructions of this primer, the web parts 32 as described in FIGS. l-4 could be substituted for post 72.

The anvil 30 and the primer cover 40 including its power charge 46 of the primer shown in FIGS. ll-4 and above-described preferably constitute components of the primer shown in FIGS. 5-9. Anvil 30, which is preferably spherical in shape, is supported upon end face 80 of post 72. Primer cover 40 is inserted into bore 60 in a light press fit with its side wall 42 encircling anvil 30 with clearance and its end wall 44 spaced from the anvil. The outer face of cover end wall 44 and the outer face 82 of cup 64 are preferably coplanar. The primer charge 46 carried within cover 40 preferably makes light contact with anvil 30. The leading edge 52 of cover 40 is preferably slightly spaced from web parts 74. When cover end wall 44 is struck by the firing pin of a gun, cover 40 moves into cup 64 and causes the powder charge 46 inside the cover to make forceable detonating contact with the anvil 30 which is supported by post 72. Detonation of the primer powder charge causes the rupturing of wall parts 78 of the cup which permits the fire from the primer powder charge to enter cartridge powder chamber 17, thereby causing the detonation of powder charge 22 therein. Cup 64 is preferably of a molded composition, such as polyethylene, polypropolene, or ABS polymers. Cover 42 may be formed from a metal material or plastic. Anvil 30 may be formed of a metal or hard plastic.

It is to be understood that this invention is not to be limited to the details herein given but that it may be modified within the scope of the appended claims.

What I claim is:

1. A primer for an ammunition cartridge comprising means having a hole therein and including a side wall defining said hole, a spherical member disposed within said hole, means supporting said spherical member being carried by said hole-defining means, a cover having a side wall and an end wall, said cover side wall extending into said hole with said end wall being spaced from said spherical member, a powder charge disposed between said spherical member and end wall detonatable upon the application of a percussive force to said cover.

2. The primer of claim 1 wherein said spherical member is spaced from said hole-defining means side wall, said cover side wall encircling said spherical member and being positioned between said hole-defining means side wall and spherical member.

3. The primer of claim 1 wherein said hole-defining means constitutes a battery cup adapted for insertion into the base of said ammunition cartridge.

4. The primer of claim 1 wherein said hole-defining means constitutes an integral part of the base of said ammunition cartridge.

5. A combined shot shell casing and primer wherein said casing has a tubular portion and an end wall portion, said tubular portion defining at least in part a powder chamber, said end wall portion including an outer face and having a primer cavity, said primer cavity opening at said outer face and defined by a side wall and an end wall, said end wall defining a support means, an anvil seated within said support means, a primer cover having an end wall and a side wall, said primer cover inserted into said primer cavity and having its end wall spaced from said anvil, and a primer powder charge disposed between said cover end wall and anvil and being detonatable upon application of a percussive force to said pn'mer cover.

6. The casing and primer of claim 5, wherein said support means includes a plurality of web parts extending radially outwardly from the longitudinal axis of said primer cavity, each web part having a beveled end edge cooperating with the beveled end edge of at least one other web part to define converging seating surfaces engaging said anvil.

7. The casing and primer of claim 6, wherein adjacent web parts form an interstice therebetween, said end wall portion having a thin-walled part at the base of said interstice, said thin-walled pan separating said primer cavity and powder chamber and being rupturable upon detonation of said primer charge.

8. The casing and primer of claim 5, wherein said anvil is spherical in shape and said cover side wall encircles said anvil with clearance.

- 9. A primer for an ammunition cartridge comprising a battery cup adapted for insertion into the base of said ammunition cartridge, said cup having a side wall, a ball-shaped anvil disposed within said cup and spaced from said side wall, means carried by said cup for supporting said anvil within said cup, a cover having a side wall and end wall, said cover side wall encircling said anvil with clearance, said end wall being spaced from said anvil, a powder charge disposed between said anvil and end wall detonatable upon the application of a percussive force to said cover.

10. The primer of claim 9 wherein said anvilsupporting means is a post extending longitudinally within said cup and having a concave end face at one of its ends, said post being spaced from said cup side wall and joined at the other of its ends to said cup by spaced radially projecting web parts, each web part extending from said post to said cup side wall, said anvil seated on said concave post end face, said cover side wall extending between said post and cup side wall.

Claims

5. A combined shot shell casing and primer wherein said casing has a tubular portion and an end wall portion, said tubular portion defining at least in part a powder chamber, said end wall portion including an outer face and having a primer cavity, said primer cavity opening at said outer face and defined by a side wall and an end wall, said end wall defining a support means, an anvil seated within said support means, a primer cover having an end wall and a side wall, said primer cover inserted into said primer cavity and having its end wall spaced from said anvil, and a primer powder charge disposed between said cover end wall and anvil and being detonatable upon application of a percussive force to said primer cover.

7. The casing and primer of claim 6, wherein adjacent web parts form an interstice therebetween, said end wall portion having a thin-walled part at the base of said interstice, said thin-walled part separating said primer cavity and powder chamber and being rupturable upon detonation of said primer charge.

9. A primer for an ammunition cartridge comprising a battery cup adapted for insertion into the base of said ammunition cartridge, said cup having a side wall, a ball-shaped anvil disposed within said cup and spaced from said side wall, means carried by said cup for supporting said anvil within said cup, a cover having a side wall and end wall, said cover side wall encircling said anvil with clearance, said end wall being spaced from said anvil, a powder charge disposed between said anvil and end wall detonatable upon the application of a percussive force to said cover.

10. The primer of claim 9 wherein said anvil-supporting means is a post extending longitudinally within said cup and having a concave end face at one of its ends, said post being spaced from said cup side wall and joined at the other of its ends to said cup by spaced radially projecting web parts, each web part extending from said post to said cup side wall, said anvil seated on said concave post end face, said cover side wall extending between said post and cup side wall.