US3369443A - Shot shell process - Google Patents

Description

Feb. 20, 19% J. W, S ANSEY "3,369,443

SHOT SHELL PROCESS Filed Oct. 4, 1966 I NVENTORS' JOHN 144 SHANSEV FIG-7 limited States Patent ()fiice 3,369,443 Patented Feb. 20, 1968 3,369,443 SHOT SHELL PROCESS John W. Shansey, Alton, 111., assignor to Olin Mathieson Chemical Corporation, a corporation of Virginia Filed Oct. 4, 196,6, Ser. No. 584,191 3 Claims. (Cl. 86-10) ABSTRACT OF THE DISCLOSURE A method of combining a one-piece plastic shot shell case having a flange with a metallic cup having a rim, while insuring that the flange is fully received within the rim and the case is fully seated.

The present invention relates to ammunition casings and relates in particular to a one-piece plastic shot shell case and a method of combining such a case with a metallic cup.

More particularly, the invention deals with a novel process for combining a one-piece plastic shot shell casing formed at one end with a radially projecting flange with its complementary metallic cup having a radially projecting hollow rim for receiving the flange.

A particular feature of the invention is the provision of a novel process for ensuring that the radially projecting flange of the plastic shot shell casing enters and is fully received throughout 360 by its mating hollow rim formed in the metallic cup and that the base of the case makes areal contact with the bottom of the cup.

A representative embodiment of the present invention may comprise the steps of reforming the flange from its radially projecting or first position to a second position defining a circular skirt depending from the tubular casing so that the skirt and the tubular casing are generally coaxial, inserting the casing so reformed into a metallic cup until the casing bottoms in the cup, said circular skirt by virtue of its natural tendency to return to its first position tending to feed into or enter said hollow rim as the casing bottoms, and thereafter forcing or working the casing relative to the cup to ensure that the hollow rim is filled throughout its circumference by said flange, and

the base of the case in in areal contact with the bottom of the cup.

Other features and advantages of the present invention will become more apparent from an examination of the succeeding specification when considered in conjunction with the appended drawings, in which:

FIG. 1 is a vertical section of a loaded shot shell where the plastic casing and the metallic cup have been combined in accordance with the principles of the invention;

FIG. 2 is a vertical section of the head or base portion of a plastic shot shell before combination with a metallic p;

FIG. 3 is a similar section of a metallic cup with which the base portion of FIG. 2 is combined;

FIG. 4 shows tooling for reforming the flange from the radial position to the depending position;

FIG. 5 shows the step following the representation of FIG. 4;

FIG. 6 is an enlarged view of a portion of FIG. 5 showing the relationship of the flange and rim at the instant of bottoming; and

FIG. 7 is an enlarged view of FIG. 1 showing the finished assembly after the final working or forcing step with the flat faces of the flange and the boss in a coplanar position.

Referring now in detail to the drawings, note that FIG. 1 shows a plastic shot shell case identified as P in combination with a metallic cup M where one end of the case P includes a radially projecting flange F mating with a corresponding hollow rim R.

As stated previously, the present invention is directed to a novel process for more efficiently affecting the combination of the shot shell casing with a metallic cup to ensure that the casing flange interlocks or mates with the hollow rim throughout their respective peripheries and that the bottom of the case makes areal contact with the cup.

FIG. 2 shows the head 10 of a plastic shot shell including a radially projecting flange 11 having a flat annular face 12 surrounding and offset from a boss 13 also having a flat face.

Aperture 14 is provided for receiving a primer assembly such as is represented in FIG. 1 by the letter A. FIG. 3 shows a metallic cup 16 having a hollow rim 17; the dimensions of the cup 16 including its hollow rim 17 are selected to complement the casing 10 and its flange 11.

FIG. 4 shows the casing 10 entering a forming die 18 whose tapered side wall 19 is operative as the casing is advanced in the direction of the arrow by mandrel 21 to reform flange 11 from its radial condition of FIG. 2 into a circular depending skirt identified in FIG. 4 by the reference numeral 22.

FIG. 5 illustrates the relative position of the metallic cup 16 and the casing 10 at the instant of bottoming.

In this figure, it is apparent that female die 23 serves as a seat for metallic cup 16 as well as for primer 24 shown in position in primer aperture 14.

Referring now to FIG. 6, which is an enlarged view of a portion of FIG. 5, note that the flat face 26 of boss 13 is in face-to-face contact with the mating surface of the cup 16.

Note further that the flange 11, while having returned to its generally radial position, has not fully entered the hollow rim 17 of the metallic cup 16.

Furthermore, note that the face 12 of the flange 11 is not fully in contact with the flat face of the metallic cup 16 nor are the faces of the boss and the flange coplanar.

Upon the application of additional pressure by the tooling of FIG. 5, the rim 17 of the cup is crimped and the plastic case is forced or worked so that the assembled elements assume the condition shown in FIG. 1. (See FIG. 7, an enlargement of a portion of FIG. 1).

Referring in particular to FIG. 7, note that upon completion of the final step, the flange 11 fully enters and entirely occupies the hollow rim 17. In addition, the flat faces 12 and 26 of the flange 11 and the boss 13, respectively, are coplanar but are intercepted by an annular undercut or groove defined by the reference numeral 27.

The particular advantage of the present invention is to develop a uniform hoop stress encircling and compressing primer A while insuring that the base of the plastic case is snugly in areal contact with the bottom of the metal cup.

In prior art arrangements and without the process steps of the present invention, the flange 11 does not enter the hollow rim fully throughout 360 and frequently there is a gap or space between the base of the case and the cup. When the flange 11 is not fully seated or when the flange 11 buckles or otherwise refuses to enter and fill out the mating portion of the hollow rimthroughout 360", the primer opening 14 is deformed or distorted making it difficult to insert and retain the primer.

Correspondingly, if the case is not fully in areal contact with the bottom of the cup, the primer tends to float relative to the case causing firing difliculties.

Stated otherwise, the process steps of the present invention develop in the side walls of the primer opening 14 a uniform compressive resistance in a radial direction outwardly from the primer opening, thereby avoiding distortion in the opening and developing uniform peripheral squeeze on the primer after assembly. The primer has a firm seat assuring reliable detonation.

It is anticipated that a variety of embodiments of the present invention may be devised without departing from the spirit and scope thereof.

What is claimed is:

1. A method of combining a one-piece plastic shot shell casing having a radially projecting flange surrounding an offset boss at one end of the casing with a metallic cup having a complementary radially projecting hollow rim comprising the steps of: reforming said radially projecting flange to define a circular skirt depending from the tubular body so that the skirt is generally coaxial with the tubular body, inserting said casing with the reformed flange into said metallic cup until the oflset boss bottoms in the cup, said depending skirt by virtue of its natural tendency to return to its condition defining a radially projecting flange tending to feed into said hollow rim as the offset boss bottoms in the cup, and after bottoming said olfset boss working said plastic casing particularly said offset boss relative to said cup to drive said flange radially into the hollow rim to ensure that said hollow rim is completely filled throughout its circumference by said flange and that said casing is in areal contact with the bottom of said cup, the plastic material fo said offset boss providing during said working step a body of plastic material useful to drive said flange outwardly in a radial direction.

2. The method of claim 1, wherein the working step after bottoming eliminates the offset condition of the boss and renders the face of the flange and the boss coplanar.

3. A method of combining a one-piece plastic shot shell casing with a metallic cup having a radially projecting hollow rim comprising the steps of: forming a one-piece plastic shot shell casing with a tubular body and with a circular, radially projecting flange at one end of the tubular body, turning said flange downwardly through an arc of about 90 so that the flange forms a circular skirt depending from the tubular body, inserting said one-piece casing with said circular skirt into the metallic cup until the casing bottoms in the cup, said flange by virtue of its natural tendency to return to its radially projecting position being operative to feed into said hollow rim as the casing bottoms in the cup effective to ensure that said hollow rim is completely filled throughout its circumference by said flange.

References Cited UNITED STATES PATENTS 977,497 12/1910 Bailey 86-12 3,242,789 3/1966 Woodring 86-1l BENJAMIN A. BORCHELT, Primary Examiner.

P. A. SHANLEY, G. H. GLANZMAN,

Assistant Examiners.

Images