US3439618A - Wet charged percussion cap - Google Patents

Description

April 22, 1969 GAWLJCK ET AL WET CHARGED PERCUSSION CAP Filed Sept. 21, 1967 FIG. 2b

FIG. lb

' INVENTORS HEINZ GAWLICK FlG.3b

mum BENDLER BY p 9 ATTORNEY- United States Patent 3,439,618 WET CHARGED PERCUSSION CAP Heinz Gawlick and Hellmut Bendler, Furth, Germany, as-

signors to Dynamit Nobel Aktiengesellschaft, Troisdorf, Germany Filed Sept. 21, 1967, Ser. No. 669,628

Int. Cl. F42c 19/10 US. Cl. 102-865 Claims ABSTRACT OF THE DISCLOSURE The present disclosure relates to a primer cap, particularly of the firing pin percussion type, wherein the primer charge is introduced into the capsule of the primer cap by moist charging with an anvil provided on the primer charge and fastened to the capsule. The drying of the wet primer charge is facilitated by providing the anvil with a projection that molds the primer charge into a cup shape between the anvil and capsule during insertion. The anvil may be provided with a plurality of radially extending webs for engaging the sides of the capsule and providing spaces therebetween for receiving the primer charge so that it may be exposed to the outside for drying. Also, the anvil may be made of a permeable porous synthetic material or an impermeable synthetic material provided with perforations, to provide for the quick drying of the wet primer charge.

The dry charging of primer caps, particularly firing pin percussion caps, is particularly dangerous. Therefore, it has been advantageous, in regard to safety, to charge the primer caps with a wet primer charge; this has become increasingly popular. With wet charging, the primer composition or charge is introduced into the percussion cap capsule in the moistened condition and subsequently dried during storage within the capsule.

With dry charging of primer caps, the required amount of primer composition is easily pressed into the percussion cap in a uniform and relatively thick layer, for example 3-4 millimeters in thickness. With the prior art, it has been impossible to wet charge the primer composition in such a manner, that is in a uniform and relatively thick layer, because a uniform and thick layer of wet primer composition could not be dried satisfactorily.

It is an object of the present invention to provide for the wet charging of the primer composition with resulting safety advantages while overcoming the above-mentioned disadvantages of the prior art in regard to drying. Therefore, the present invention provides a primer cap, particularly a firing pin percussion cap with a primer composition introduced in the percussion cap in a moistened condition and with an anvil provided on the primer composition and fastened to the primer capsule to impart to the primer composition a bowl-shaped or cup-shaped distribution during charging by means of a projection on the anvil. With this feature, the surface area of the primer composition is greatly enlarged as compared to the surface area of a similar amount of primer composition in a conventional ararngement, and at the same time the thickness is reduced to such an extent that the uniform and complete drying of the primer charge is assured.

The anvil is preferably constructed of a synthetic material, for example a synthetic polymer such as polyvinyl chloride or polyethylene. The primer cap capsule is preferably made of these same materials. The anvil may be knotted within the capsule by means of a plurality of radially extending webs or arms distributed along the circumference of the anvil in a star-shaped manner to securely clamp the anvil by means of a press fit with the inner walls of the capsule.

In order to further the drying process of the wet primer 3,439,618 Patented Apr. 22, 1969 composition, or to accelerate the same, it is further proposed to make the anvil of a permeable porous synthetic material, or of a synthetic material that is impermeable and provided with perforations.

Further objects, features and advantages of the present invention will become more clear from the following detailed description of several preferred embodiments of the present invention with reference to the accompanying drawing, wherein:

FIGURES la and 1b show respectively a plan view and an axial cross sectional view of a primer cap according to the present invention together with the firing pin (FIG- URE lb being taken on the indicated cross section line of FIGURE la);

FIGURES 2a and 2b are views similar to FIGURES la and lb, respectively, but of a further specific embodiment of a primer cap according to the present invention; and

FIGURES 3a and 3b are views similar to FIGURES la and 1b, respectively, but show an additional specific embodiment of a primer cap according to the present invention.

As shown in FIGURES la and lb, the cup-shaped capsule 1 is provided with a discshaped (preferably cylindrical) bottom 2 that has a relatively thin central zone, and a tubular relatively thick outer wall 3, which is preferably also cylindrical. Preferably, the capsule 1 is constructed of a soft thermoplastic synthetic polymer material. The recess 4 is filled with a charge 5 that has been pressed by and is held in position by the mandrel-type anvil 6 provided with the perforations 7. The percussion or firing pin 8 is indicated in FIGURE 1b above the percussion cap immediately opposite the central relatively thin zone of the bottom 2. The primer charge is in a generally bowl-shaped or cup-shaped configuration of a relatively large surface area for rapid drying and is further subjected to the drying medium by means of the perforations 7.

In place of the perforated or hollow-cylindrical anvil of FIGURJES 1a and 1b, the anvil 6 of FIGURES 2a and 2b is provided in the shape of a star with four webs or arms 10 uniformly distributed about the circumference thereof at equal distances. The arms 10 tightly engage the interior cylindrical surface of the capsule 1, that is otherwise identical to the capsule 1 of FIGURES 1a and 1b, to provide a force fit for rigidly securing the anvil 6 within the capsule 1. The anvil 6 is provided with a central spike-shaped projection 9 extending toward the primer charge and bottom of the capsule; the projection 9 is pressed into the primer composition to form the primer composition into a bowl-shape or cup-shape. As in 'FIGUR'ES 1a and 1b, the central zone of the bottom of capsule 1 is relatively thin, when compared to the outer side Walls of the capsule 1; this feature has the advantage of providing only negligible resistance to the firing pin so that ignition of the primer charge is not delayed (the firing pin not being shown in FIGURES 2a and 2b). The drying of the primer composition, that is introduced in the moist state, may be accomplished with the embodiment of FIGURES 2a and 2b by way of the zones located between the adjacent webs 10, wherein the primer charge is exposed to the outside.

It is contemplated that the features of FIGURES 1a and 1b and FIGURES 2a and 2b may be combined in a single primer cap wherein the central portion of the anvil 6 or projection 9 of FIGURES 2a and 2b may be provided with perforations similar to perforations 7 shown in FIGURES 1a and lb.

Although the capsule 1 shown in FIGURES 3a and 3b differs from the capsule 1 in FIGURES 1a, lb, 2a and 2b only in its external configuration, it is contemplated that the external configuration may be the same. As shown in FIGURES 3a and 3b, the anvil 6 is provided with radially extending arms or webs 10 arranged in a star-shaped manner about the central projection 9 that presses into the primer composition to mold it into a cup shape. In contrast to FIGURES 2a and 2b, the arms of FIGURES 3a and 3b extend axially to the bottom, as viewed in FIGURE 3b, and radially outward over the front face of the capsule 1 of the primer cap and terminate flush with the outer cylindrical side walls of the capsule l. The anvil 6 is frictionally held in the capsule 1 by the inner portions of the arms 10 radially outward of the projection 9 and engaging the inner cylindrical surface of the capsule 1 and the outer portions of the arms 10 engaging the front face of the capsule 1.

It is contemplated that the features of FIGURES 3a and 3b may be combined with the above-noted combination of the features shown in FIGURES la, lb, 2a and 2b by providing the anvil 6 as shown in FIGURE 2b with an identical front extension and radial extensions of the arms 10 past the front face of the capsule 1 to terminate flush with the outer cylindrical walls of the capsule 1, as shown in FIGURE 3b. Furthermore, it is contemplated that the anvil material as well as the capsule material may be either impermeable or porous to facilitate drying of the wet primer composition.

We claim:

1. A primer cap, particularly of the firing pin percussion type, with a capsule and a primer charge introduced into the capsule of the primer cap by moist charging with an anvil provided on the primer charge and fastened in the capsule of the primer cap, in combination with the improvement wherein the capsule is cup-shaped with a substantially closed bottom end and a generally axially tubular side wall forming a forward open end, the primer charge is substantially cup-shaped to provide a large surface area of relatively thin dimensions for quick drying, the anvil has projection means extending toward the closed end of the capsule directly engaging and for molding the primer charge into the cup-shape during insertion, the anvil includes a plurality of integral radially extending webs tightly engaging the interior surface of the capsule side wall with a press fit to securely hold said anvil within the capsule, said primer charge extends between said webs, and means exposing substantially the entire forwardly facing surface of said primer charge between said webs to the atmosphere.

2. The primer cap according to claim 1, wherein said anvil is constructed of a relatively permeable porous syn- .hetic material to constitute means for conducting air :hrough said anvil to the surface of said primer charge :ngaging said anvil.

"3. The primer cap according to claim 1, wherein said anvil is constructed of a relatively permeable porous naterial to constitute means for conducting air through aaid anvil to the surfaces of said primer charge engaging said anvil.

4. The primer cap according to claim 1, wherein said :apsule tubular side wall is cylindrical, said closed end is 1 bottom disk having a central relatively weakened portion :hinner than the remainder of said disk to offer negligible 'esistance to a firing pin penetration, said anvil is sub- :tantially cup-shaped opening in the same direction as taid cup-shaped capsule and being provided with a plu- 'ality of perforations axially extending therethrough and arranged uniformly in a circle, said anvil and capsule being constructed of a synthetic polymer material, said primer charge extending forwardly into said perforation.

5. The primer cap according to claim 1, wherein said capsule tubular side wall is cylindrical, said closed end is a disk having a central relatively weakened section thinner than the remainder of said disk for providing negligible resistance to penetration of a firing pin, said anvil includes a central projection extending generally axially toward said weakened section, said primer charge extending forwardly into the space immediately radially between a-djacent webs, said capsule and said anvil being constructed of a synthetic polymer material.

6. The primer cap according to claim 5, wherein said anvil extends axially forwardly beyond the forwardmost surface of said capsule, and said webs have forwardmost portions radially extending outwardly and terminating flush with the adjacent outer axially extending surface of said capsule tubular side wall, said primer composition generally filling the space between said webs and said capsule side wall.

7. The primer cap according to claim 6, wherein said anvil is additionally provided with a plurality of axially extending perforations.

8. A method of constructing a primer cap, comprising the steps of: introducing a wet primer charge into a cupshaped capsule; engaging an anvil directly with the wet primer charge, thereafter, forcing the anvil into the wet primer charge toward the bottom of the capsule to mold the wet primer charge into a cup-shaped between the anvil and the capsule; conducting air through the anvil to the interior surface of the cup-shaped primer charge and simultaneously drying the primer charge.

9. The method according to claim 8, wherein said step of forcing the anvil into the wet primer charge includes molding the wet primer charge forwardly toward the open end of the capsule between radially extending webs of the anvil.

10. The method according to claim 9, including the step of force fitting the radially extending webs of the anvil into the capsule simultaneously with the step of forcing the anvil into the wet primer charge.

References Cited UNITED STATES PATENTS 256,684 4/ 188.2 Hobbs l0286.5

750,624 1/1904 Edmunds 102-865 3,119,338 1/1964 Pissacroia 10286.5 X 3,121,394 2/1964 Anzalone 10.2-86.5 3,195,463 7/1965 Foote et al. 10286.S

FOREIGN PATENTS 1,082,044 12/ 1954 France.

735,888 4/ 1943 Germany.

BENJAMIN A. BORCHELT, Primary Examiner.

GERALD H. GLANZMAN, Assistant Examiner.

US. Cl. X.R. 86-1

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