US 3768413 A
A primer assembly which can be ignited by either impact or electrical means.
Claims available in
Description (OCR text may contain errors)
Elniied States Patent Ramsay 1 Oct. 30, 1973  ELECTRIC AND IMPACT PRIMER 2,960,032 11/1960 Sahlin 102/46 3,577,923 1971 P k' 102 46  Inventor: Marcus Ramsay, New Haven, Conn. 712826 131902 2 52 102146  Assigneez Olin Corporation, New Haven, 606,440 6/1898 Bennett 102/45 Conn- 694,265 2/1902 Von Gortz 102/45  Filed: Mar. 10, 1972 Primary Examiner-Robert F. Stahl  Appl' 233656 Attorney-Donald R. Motsko et al.
 U.S. Cl. 102/46  int. Cl. F421) 5/08  Field of Search 102/45, 46, 70.2,  ABSTRACT A primer assembly which can be ignited by either im-  References Cited pact or electrical means.
UNITED STATES PATENTS 1,485,404 3/1924 Martin 102/46 4 Claims, 4 Drawing Figures PAIENIEUum 30 ms FIG I FIG-3 ELECTRIC AND IMPACT PRIMER This invention relates to a primer assembly for use with conventional cartridges, which primer assembly can be ignited by an electrical charge or by impact with a conventional firing pin.
Primer assemblies have been designed for use with conventional cartridges for ignition by impact from a firing pin. Alternatively, other designs have been presented for primer assemblies wich can be ignited by an electrical current. Impact ignition primer assemblies are quite common and are of the same general configuration and design, generally including a primer cup, a battery cup, an anvil, and a primer charge. Electrically ignited primer assemblies are, on the other hand, rather uncommon and of somewhat exotic design. Electrically ignited primer assemblies do, however, present certain advantages over impact ignition assemblies by providing a shorter ignition time, thus providing a distinct advantage when firing at a moving target such as in skeet or trap.
The electrical-impact ignition, or universal, primer assembly of this invention includes a battery cup containing an anvil, both of rather conventional construction. A primer cup is nested into the mouth of the battery cup and contains a charge of primer material. An intermediate layer of insulating material is sandwiched between the battery cup and the primer cup to electrically insulate the latter from the former. An electrically conductive film is coated over the surface of the primer charge remote from the closed end of the primer cup, the film extending to the sides of the primer cup. As an alternative to the inclusion of an electrically conductive film, the primer charge can be made electrically cnductive by inclusion therein of conductive particles. The primer assembly can be fired either by touching the closed end of the primer cup with a charged electrode, or by impacting the closed end of the primer cup with a firing pin.
It is, therefore, an object of this invention to provide a primer assembly which can be fired either electrically or by impact.
It is a further object of the invention to provide a primer assembly of the character described which can be readily produced with existing manufacturing knowhow and facilities and used with conventional cartridges in place of the conventional impact ignition primer assemblies.
These and other objects and advantages of the invention will become more readily apparent from the following detailed description of a preferred embodiment of the invention when taken in conjunction with the accompanying drawings, in which:
FIG. 1 is a vertical cross-sectional view of a preferred embodiment of the primer assembly of this invention;
FIG. 2 is a cross sectional view of a portion of a conventional cartridge having as a component thereof the primer assembly of FIG. 1;
FIG. 3 is a vertical sectional view of a portion of a firearm showing the cartridge of FIG. 2 chambered for firing by an electrical ignition system; and
FIG. 4 is a vertical sectional view of a portion of a firearm showing the cartridge of FIG. 2 chambered for firing by an impact ignition system.
Referring now to the drawings, FIG. 1 discloses a preferred embodiment of the primer assembly formed in accordance with this invention. The primer assembly includes a battery cup 2 into which is press-fitted a primer cup 4. A layer of insulating material 6 is sandwiched between the battery cup 2 and the primer cup 4 to electrically insulate the primer cup from the battery cup. A charge of priming material 8 is deposited within the primer cup 4 and a film of electrically conductive material 10, such as carbon or the like, is deposited on the surface of the priming material 8. The side edges of the conductive film are in electrical contact with the primer cup 4. An anvil member 12 is positioned within the battery cup 2. It will be noted that the battery cup 2, the primer cup 4, and the anvil 12 are of conventional construction, and the primer material 8 is positioned within the primer cup in a conventional manner.
It will be noted that the anvil 12 contacts the conductive layer 10 and also contacts the battery cup 2. The conductive layer 10 is formed from a conductive resistance material which heats up when subjected to an electrical current. The circuit is grounded to the firearm through the anvil 12, battery cup 2 and intervening cartridge casing (see FIGS. 3 and 4).
Referring now to FIG. 2, the primer assembly of FIG. 1 is shown positioned in a cartridge which cartridge is of conventional construction. The cartridge includes a basal end wall 14 provided with a primer aperture 16 opening into a flash hole 18. The flash hole in turn opens into a cavity 20 in which is packed a propellant charge 22. The primer assembly is press-fitted into the primer aperture in a normal manner. The remainder of the cartridge, which is not shown, is of conventional construction and includes a projectile of some sort which is fired by deflagration of the propellant charge 22. This deflagration of the propellant charge is initiated by combustion of the primer charge, which causes a flame to flash through the flash hole 18 into the propellant charge 22 to ignite the latter.
Referring now to FIG. 3, the cartridge is shown chambered in the firing chamber of a firearm. The configuration of the firing chamber of the firearm is conventional, however, the firearm shown in FIG. 3 is one which is adapted for firing ammunition electrically. The firing chamber 24 is disposed in the barrel 26 of the firearm, and the firearm includes a reciprocating bolt member 28 which extends into the barrel 26 and closes off the rear end of the firing chamber 24. The bolt 28 includes an electrode 30 positioned on its axis so that when the bolt 28 is in its battery position, as shown in FIG. 3, the tip of the electrode 30 contacts the primer cup 4. When one pulls the trigger of the firearm, an electrical current is caused to pass through the electrode and thence to the battery cup 4 and the conductive film 10 to electrically heat the latter and ignite the primer charge 8. As previously noted, the circuit is grounded to the firearm barrel 26 by the anvil l2, battery cup 2 and cartridge wall 14. The circuitry and switches used to pass an electrical current to the electrode when the trigger is pulled will preferably include a battery and discharging capacitor. The arrangement shown in my U.S.'Pat. No. 3,580,113, issued May 25, 1971, can be used for this purpose.
Referring now to FIG. 4, there is shown the firing chamber portion of a conventional impact ignition type firearm which includes a firing chamber 32 formed in a rearward portion of the firearm barrel 34. A reciprocating bolt member 36 extends into and closes off the rearward end of the firing chamber 32 in a conventional manner. The bolt 36 includes a firing pin 38 which is normally spring-biased rearwardly to the position shown in FIG. 4. When the trigger of the firearm is pulled, a hammer or striker is caused to impact the rearward end of the firing pin 38 thus driving the latter forward against the primer cup 4. The primer cup is thus deformed inwardly against the anvil 12 causing compression of the primer charge 8 between the anvil and the primer cup thus causing the primer charge 8 to ignite.
It will be readily appreciated that the primer assembly of this invention can be fired by either an electrical arrangement wherein an electrical current is delivered to the primer cup to ignite the primer charge or, alternatively, by a conventional firing pin or hammer which is caused to strike the primer cup thus crushing the primer charge between the primer cup and anvil, thus causing ignition of the primer charge. Thus, a universal primer assembly is provided which does not have to be modified to be fired by either electrical or impact means. From a manufacturing standpoint, only minor modifications need be made to the standard impact type primer assembly to adapt the latter for firing by electrical current in accordance with this invention.
Since many changes and variations of the disclosed embodiment of the invention may be made without departing from the inventive concept, it is not intended to limit the invention otherwise than as required by the appended claims.
What is claimed is:
l. A primer assembly which can be fired both by impact and electrically, and which comprises:
a. a battery cup;
b. a primer cup nested in said battery cup;
c. a layer of electrical insulating material sandwiched between said primer cup and said battery cup to electrically insulate the former from the latter;
d. a charge of priming material deposited in said primer cup;
e. electrically conducting means for producing heat when subjected to an electrical current, said conducting means contacting said priming material and said primer cup; and
f. anvil means contacting said electrically conducting means and said battery cup for conducting an electrical current from said electrically conducting means to said battery cup and for crushing at least a portion of said priming material against said primer cup upon delivery of an impact blow to said primer cup.
2. The primer assembly of claim 1, wherein said electrically conducting means is a film of electrically conductive material contacting on one surface of said priming material and sandwiched between said anvil means and said priming material.
3. The primer assembly of claim 1, wherein said electrically conducting means is in particulate form dispersed throughout said charge of priming material.
4. In a primer assembly of the type including a battery cup, a primer cup nested in said battery cup and containing a charge of priming material, and an anvil positioned in said battery cup in contact with the latter and operative to crush at least a portion of the priming material against the primer cup upon delivery of an impact blow to the primer cup, the improvement comprising:
a. an insulating material sandwiched between said primer cup and said battery cup to electrically insulate the former from the latter; and
b. electrical conducting means contacting said priming material, said primer cup and said anvil, said electrical conducting means being operable to produce heat when subjected to an electrical current.