US3427920A

US3427920A - Base wad

Info

Publication number: US3427920A
Application number: US646929A
Authority: US
Inventors: Homer E Clark Jr
Original assignee: Alcan Co Inc
Current assignee: Alcan Co Inc
Priority date: 1967-06-19
Filing date: 1967-06-19
Publication date: 1969-02-18
Anticipated expiration: 1986-02-18

Description

Feb. 18, 1969 H. E. CLARK, JR 3,427,920

BAS E WAD Filed June 19, 1967 FIG! FIGZ- FIGS 5 I 1 FIG. 6

1 i l l? j INVENTOR HOMER E. CLARK, JR.

BY N

ATTORNEY United States 3,427,920 BASE WAD Homer E. Clark, Jr., Alton, Ill., assignor to Alcan Company, Incorporated, Alton, 111., a corporation of Illinois Filed June 19, 1967, Ser. No. 646,929 US. Cl. 86-12 Int. Cl. F42b 7/02 3 Claims ABSTRACT OF THE DISCLOSURE Background of the invention In order to prevent distortion of the head of a shotgun cartridge so that the same remains strong and solid, it is necessary to prevent gas leakage into the head area upon explosion of the shotgun cartridge propellant. Base wads have been heretofore developed in an eflort to seal the headed end of cartridges against gas leakage as well as to serve to integrate the cartridge head structure. However, currently known base wads have not, in practice, provided the gas-tight seal desired, thereby causing head distortion with resultant poor extraction. There have been attempts to construct base wad overlays for superimposition upon base wads for the purpose of promoting the requisite blockage against gas leakage through the head portion. But the use of such overlays has expectedly complicated manufacturing and added substantially to the cost thereof. Actually, base wad overlays have not fully solved the problem of inhibiting gas leakage. The present invention provides a unique base wad which in usage will present a most effective gas seal.

Summary of the invention It is a primary object of the present invention to provide a base wad which may be integrally formed of suitable moldable material, and hence is amenable to lowcost, high-volume production.

It is another object of the present invention to provide a base wad of the character stated which incorporates a peripheral flange at its normally inner end which is inherently biased into snug engagement with the confronting wall portion of the cartridge casing to provide a seal against gas leakage.

It is another object of the present invention to provide a method for rapidly and economically producing a base wad having a flange inherently urged into tight, gasleakage-proof contact with the cartridge casing.

It is a still further object of the present invention to provide a base wad of the character stated which is reliable and durable in usage; which integrates the cartridge head structure; and which is resistant to distortion upon firing.

Brief description of the drawing FIGURE 1 is a side elevational view of a base wad constructed in accordance with the present invention, illustrating same prior to the flange shaping operation.

FIGURE 2 is a bottom plan view of the base wad as illustrated in FIGURE 1.

FIGURE 3 is an elevational view, in partial section, illustrating the base wad of FIGURE 1 positioned within a forming die preparatory to the flange shaping operation.

FIGURE 4 is an elevational view, in partial section, illustrating the base wad during the flange shaping.

Patent 3,427,920 Patented Feb. 18, 1969 ice FIGURE 5 is an elevational view, in partial section, illustrating the shaped base Wad as presented within the casing of a shotgun cartridge.

FIGURE 6 is a side view of a shotgun cartridge, a portion of the side wall being broken away, incorporating a base wad produced in accordance with and embodying the present invention.

FIGURE 7 is a side elevational view of another form of base wad constructed in accordance with and embodying the present invention, illustrating the same prior to the flange shaping operation.

FIGURE 8 is an elevational view in partial section illustrating the base wad of FIGURE 7 positioned within a forming die preparatory to the flange shaping operation.

Description of the preferred embodiment Referring now by reference characters to the drawing which illustrates the preferred embodiment of the present invention, A designates a base wad for a shotgun cartridge, being formed from suitable moldable plastic material, such as thermoplastics, including normal and linear polyethylene, as well as those from acrylic resins, vinyl resins, etc., wherein the material provides an inherent resiliency, and having a cylindrical body portion 1 which is provided with a central axial bore 2 for receiving a primer. Integrally formed with body 1 and extending radially from the normally inner or upper end thereof, is a peripheral flange 4, the plane of which is coincident with the plane of the said inner or upper end portion of said body 1, being perpendicular to the axis of bore 2. Flange 4 is relatively thin with respect to the over-all thickness or height of body 1, but is of suflicient thickness so as to have a strength inherently urging same into planar perpendicularity with respect to the longitudinal axis of wad A, that is, into radial projection as seen in FIGURE 1.

In order to complete formation of basewad A for disposition within a shotgun cartridge, it is requisite to turn flange 4 through an angle of approximately so that the same will extend endwise of body 1; describing an annulus coaxial with wad A. Such forming or shaping forces flange 4 against its inherent bias. To accomplish the drawing of flange 4 from a flat state to a cuplike condition with body 1, base wad A is subjected to the action of a punch 5 and drawing or shaping die 6. Said die 6 is of the push-through type having a die opening or bore 7 for reception of body 1 and which in its lower portion is of constant diameter and at its upper end is continuous with an upwardly and outwardly inclined flared recess 8 having an angle to the vertical of substantially 45. The outer extremity, or wider end, of recess 8 is of a diameter for accepting flange 4 (FIGURE 3).

Base wad A, as molded with flange 4 extending radially, is inserted into die opening 7 with flange 4 presented within flared recess 8 as shown in FIGURE 3. Punch or male die 5 is of a diameter less than that of body 1 of base wad A so that upon shaping of flange 4 by the forming operation, the same will not interfere therewith.

A shotgun cartridge casing 11, as fabricated of metal, paper, plastic, or the like, is positioned below die 6 in alignment with die-opening 7 so that through its open upper or die-adjacent end it will receive the shaped base wad A as the same is pushed through said opening 7. Thus, upon downward thrust of punch 5, wad A will be forced through opening 7 of die 6, causing flange 4 to be bent through an angle of substantially 90 by reason of the contour of flared recess 8 and opening 7 to be caused to project in an endwise manner, as may best be seen in FIGURE 4. The continued downward travel of punch 5 forces wad A through die 6 and into casing 11 (FIGURE 5). It will be seen that by the inner walls of opening 7 of die 6 and of casing 11, flange 4 will be restrained against returning to outward or initial radial position, within a plane substantially normal to the axis of base wad A. Through its inherent bias, as by reason of its original character and of its material of construction, which being plastic will possess an inherent resiliency, said flange 4 will be urged outwardly and thereby effect a tight surface contactive engagement with the inner face of tubular casing 11 which urging renders the joint developed therebetween proof against gas leakage.

Casing 11 with the received base wad A is then subjected to the customary heading operation for securing a head 12 upon the normally lower end of casing 11 and with base wad A being thereupon subjected to the opera- Within the range of to 25 tons for forcing base wad A into operative position and causing material to flow into the rim area for strengthening the cartridge and to present the area surrounding the primer for better gas sealing. Said internal punch will effect an annular depression in the confronting end face of base wad A as may best be seen at 3 in FIGURE 6.

Base wad A is thus a self-sufficient unit, not requiring the superimposition of a base wad overlay to bring about a positive sealing engagement.

FIGURE 6 illustrates a shotgun cartridge B having a tubular casing 11, head 12, with base wad A mounted therein as by the procedure above described. Received within bore 2 of base wad A is a primer 13 having an enlarged outer end 14 for reception within the counter-bore 3. A propellant charge 15 is provided upon base wad A, with an obturating wad 16 surmounting said charge 15; there being the customary filler or

separator wads

17, 18 provided upwardly of obturating wad 16, and with a missile charge 19 presented above wad 18. The upper end portion of casing 11 may be folded inwardly or crimped for closing cartridge B and completing the assembly thereof.

The tendency of plastic to return to its original molded form is referred to generally as memory and it is this characteristic which assures of outward pressure of flange 4 for bringing about a tight-joint with casing 11.

With reference now being made to FIGURE 7, it is to be recognized that the original presentation of the flange may extend at an angle of less than 90 to the longitudinal axis of base wad A. Thus, in said figure, A designates a base wad having a cylindrical body 21 with a central axial bore 22 which are in all respects similar to the corresponding portions of base wad A above described. Extending peripherally from one end of body 21 is a flange or skirt 24 which is outwardly flared as at an angle of approximately 45 to the longitudinal axis of said base wad A. The said base wad A may be subjected to the same forming action as base wad A with the flange 24 being forced inwardly through an angle, in this instance, approximately 45 so as to provide an annular skirt coaxial with base wad A.

Thus, the form of base wad shown in FIGURE 7 is but illustrative of the provision of a flange at an angle of less than 90 which may be shaped to bring about the desired gas-sealing action through the aforesaid memory thereof. Consequently, the greater the angle through which the flange is turned the seemingly stronger would be the joint effected although obviously efficacious joints may be formed as a result of a turning through less than 90.

FIGURE 8 illustrates another type of die for forming base wad A; said die being indicated at 26 and being of "tion" of anin'ternalpunch' under substantial pressures as a the push-through type and having a die opening or bore 27 for reception of body 1. The outer end of die opening 27 is continuous with a mouth portion having a diameter considerably less than that of flange 4 but being formed on a slight radius as at R so as to guide the flange in the course of the shaping operation. Thus, dies having other than the flared recess 8 of die 6 are equally effective in bringing about the desired flange formation.

Having thus described my invention, what I claim and desire to obtain by Letters Patent is:

1. A method for installing a base wad within a shotgun cartridge having a casing, a powder charge provided in said casing, and said casing having a missile-discharge or forward end. and ahead orreatwa idfill z S i me h d comprising:

(1) Providing a molded base wad from a suitable thermo-plastic and having normally forward and rearward planar parallel faces, said forward face being directed toward said powder charge, said base wad having a cylindrical body portion, a continuous radially extending peripheral flange provided on the forward face, said flange being disposed at an angle of less than to the proximate forward end face of said base wad,

(2) Placing said base wad body portion in a forming die having a die opening of substantially like diameter as the body portion of said base wad,

(3) Presenting the forward end of said cartridge casing at one end of said die opening and in alignment therewith,

(4) Providing a flared recess at the end of said die opening opposite to that adjacent to that of said cartridge casing,

(5) Disposing said base wad in said die opening with said peripheral flange being received within said flared recess and with the lower end face of said body portion of said base wad being presented toward the forward end of said casing,

(6) And then applying pressure against the forward face of said base wad for forcing same through said die opening and into the forward end of said casing for travel toward the rearward end thereof, said flange being progressively restricted by said flared recess so as to be turned to extend endwise of said base wad forming an annulus coaxial with said base wad body portion.

2. The method for producing a shotgun cartridge base wad as defined in claim 1 and further characterized by said flared recess having a greater cross-section in its portion remote from said die opening than the portion immediately adjacent said die opening.

3. The method for producing a shotgun cartridge base wad as defined in claim 1 and further characterized by the provided molded base wad having a peripheral flange surrounding its forward end face within the same plane as the said forward end face.

References Cited UNITED STATES PATENTS 1,066,980 7/1913 Bailey 86-12 3,157,121 11/1964 Daubenspeck et al. l0242 3,229,634 l/ 1966 Moehlman et al l0242 3,246,603 4/1966 Comerford l0244 X ROBERT F. STAHL, Primary Examiner.

US. Cl. X.R.