Method of making polymer ammunition cartridges having a two-piece primer insert

• US 9,506,735 B1
• Filed: 03/09/2016
• Issued: 11/29/2016
• Est. Priority Date: 03/09/2016
• Status: Active Grant

• Current Assignee: Velocity Holdings LLC (Centerpoint Energy Incorporated)
• Original Assignee: True Velocity, Inc.
• Inventors: Burrow, Lonnie
• Primary Examiner(s): Hayes, Bret
• Assistant Examiner(s): MORGAN, DERRICK R
• Application Number:
  US15/065,299
• Time in Patent Office: 265 Days
• Field of Search: 102/430, 102/464, 102/465, 102/466, 102/467, 102/469, 102/470
• US Class Current: 1/1
• CPC Class Codes: F42B 33/001 Devices or processes for assembling ammunition, cartridges or cartridge elements from parts
• CPC Class Codes: F42B 33/04 Fitting or extracting primers in or from fuzes or charges F42B33/004 takes precedence
• CPC Class Codes: F42B 5/181 consisting of a combustible casing wall and a metal base; Connectors therefor
• CPC Class Codes: F42B 5/30 of plastics , i.e. the cartridge-case tube is of plastics
• CPC Class Codes: F42B 5/307 formed by assembling several elements
• CPC Class Codes: F42B 5/313 all elements made of plastics
• CPC Class Codes: F42C 19/0815 Intermediate ignition capsules, i.e. self-contained primary pyrotechnic module transmitting the initial firing signal to the secondary explosive, e.g. using electric, radio frequency, optical or percussion signals to the secondary explosive initiators for blasting cartridges or air bags F42B3/10
• CPC Class Codes: F42C 19/083 characterised by the shape and configuration of the base element embedded in the cartridge bottom, e.g. the housing for the squib or percussion cap

Abstract

The present invention provides a method of making an ammunition cartridge having a two piece primer insert by forming a two piece primer insert that is overmolding with a cylindrical polymeric middle body and joining a cylindrical polymeric bullet-end component to the cylindrical polymeric middle body to form a polymer ammunition cartridge.

Claims

1. A method of making an ammunition cartridge having a two piece primer insert comprising the steps of:

forming a substantially cylindrical primer insert by providing an upper primer insert portion comprising an upper primer bottom surface, an upper primer aperture through the upper primer bottom surface;

a substantially cylindrical coupling element extending away from the upper primer bottom surface, and an interior surface inside the substantially cylindrical coupling element;

providing a lower primer insert portion comprising a lower primer bottom surface opposite a lower primer top surface, a primer recess in the lower primer top surface that extends toward the lower primer bottom surface and adapted to fit a primer, a lower primer aperture through the lower primer bottom surface, and a flange that extends circumferentially about an outer edge of the lower primer bottom surface, wherein the flange is adapted to receive a polymer overmolding;

aligning the upper primer bottom surface and the lower primer bottom surface to align the lower primer aperture with the upper primer aperture and forming an insert joint;

linking the upper primer bottom surface and the lower primer bottom surface to form a primer insert;

providing a primer flash hole aperture extending through the lower primer aperture and the upper primer aperture;

providing a first polymer composition for molding a polymer ammunition cartridge;

molding from the first polymer composition a substantially cylindrical polymeric middle body having the substantially cylindrical primer insert at a first end and a substantially cylindrical polymeric coupling region at a second end, wherein the first polymer composition extends over an outer surface of the substantially cylindrical primer insert over the flange and the first polymer composition extends over an interior surface of the substantially cylindrical coupling region into the primer flash hole aperture forming a flash hole, wherein the first polymer composition extends from the substantially cylindrical polymeric coupling region into the primer flash hole aperture;

forming a substantially cylindrical polymeric bullet-end component from a second polymer composition comprising a bullet aperture opposite a polymeric bullet-end coupling that mates to the substantially cylindrical coupling region; and

coupling the substantially cylindrical coupling region to the polymeric bullet-end coupling to form a propellant chamber that extends from the primer flash hole aperture to the bullet aperture.

2. The method of claim 1, wherein the upper primer insert portion, the lower primer insert portion or both independently formed by metal injection molding, polymer injection molding, stamping, milling, molding, machining, punching, fine blanking, smelting, or any other method that will form insert portions that may be joined together to form a primer insert.

3. The method of claim 1, wherein linking is by threading, riveting, locking, friction fitting, coining, snap fitting, chemical bonding, chemical welding, soldering, smelting, sintering, adhesive bonding, laser welding, ultrasonic welding, friction spot welding, friction stir welding spin-welding, vibration-welding, ultrasonic-welding, laser-welding techniques or a combination thereof.

4. The method of claim 1, wherein the upper primer insert portion, the lower primer insert portion or both independently comprises a polymer, a metal, an alloy, or a ceramic alloy.

5. The method of claim 1, wherein the upper primer insert portion and the lower primer insert portion are made of the same material or different materials.

6. The method of claim 1, wherein the upper primer insert portion and the lower primer insert portion comprise different polymers, different metals, different alloys, or different ceramic compositions.

7. The method of claim 1, wherein the upper primer insert portion comprises a polymer, a metal, an alloy, or a ceramic alloy and the lower primer insert portion comprises different polymer, metal, alloy, or ceramic alloy.

8. The method of claim 1, wherein the upper primer insert portion and the lower primer insert portion comprise steel, nickel, chromium, copper, carbon, iron, stainless steel brass or a combination thereof.

9. The method of claim 1, wherein the upper primer insert portion, lower primer insert portion or both comprises 102, 174, 201, 202, 300, 302, 303, 304, 308, 309, 316, 316L, 316Ti, 321, 405, 408, 409, 410, 415, 416, 416R, 420, 430, 439, 440, 446 or 601-665 grade stainless steel or Ti₆Al₄V.

10. The method of claim 1, further comprises a flash hole groove that extends circumferentially about the upper primer aperture or the lower primer aperture.

11. A method of making an ammunition cartridge having a two piece primer insert comprising the steps of:

providing a two piece primer insert for ammunition comprising;

an upper primer insert portion comprising an upper primer bottom surface opposite an upper primer top surface, an upper primer aperture through the upper primer bottom surface and the an upper primer top surface;

a flash hole groove that extends circumferentially about the upper primer aperture on the upper primer bottom surface, a substantially cylindrical coupling element extending away from the upper primer top surface, and an interior surface inside the substantially cylindrical coupling element;

a lower primer insert portion comprising a lower primer bottom surface opposite a lower primer top surface, a primer recess in the lower primer top surface that extends toward the lower primer bottom surface and the primer recess adapted to fit a primer, a lower primer aperture through the lower primer bottom surface, and a flange that extends circumferentially about an outer edge of the lower primer bottom surface, wherein the flange is adapted to receive a polymer overmolding; and

an insert joint that links the upper primer bottom surface and the lower primer bottom surface to align the lower primer aperture with the upper primer aperture and form the two piece primer insert;

providing a primer flash hole aperture extending through the lower primer aperture and the upper primer aperture;

providing a first polymer composition for molding a polymer ammunition cartridge;

molding from the first polymer composition a substantially cylindrical polymeric middle body having the two piece primer insert at a first end and a substantially cylindrical polymeric coupling region at a second end, wherein the first polymer composition extends over an outer surface of the two piece primer insert over the flange and extends over the interior surface of the substantially cylindrical coupling element into the primer flash hole aperture forming a flash hole, wherein the first polymer composition extends from the substantially cylindrical polymeric coupling region into the primer flash hole aperture;

forming a substantially cylindrical polymeric bullet-end component from a second polymer composition comprising a bullet aperture opposite a polymeric bullet-end coupling that mates to the substantially cylindrical polymeric coupling region; and

coupling the substantially cylindrical polymeric coupling region to the polymeric bullet-end coupling to form a propellant chamber that extends from the primer flash hole aperture to the bullet aperture.

12. The method of claim 11, wherein the upper primer insert portion, the lower primer insert portion or both are independently formed by metal injection molding, polymer injection molding, stamping, milling, molding, machining, punching, fine blanking, smelting, or any other method that will form insert portions that may be joined together to form a primer insert.

13. A method of making an ammunition cartridge having a two piece primer insert comprising the steps of:

forming a two piece primer insert comprising the steps of;

forming an upper primer insert portion comprising an upper primer bottom surface, an upper primer aperture through the upper primer bottom surface;

a substantially cylindrical coupling element extending away from the upper primer bottom surface, and an interior surface inside the substantially cylindrical coupling element;

forming a lower primer insert portion comprising a lower primer bottom surface opposite a lower primer top surface, a primer recess in the lower primer top surface that extends toward the lower primer bottom surface and the primer recess adapted to fit a primer, a lower primer aperture through the lower primer bottom surface, and a flange that extends circumferentially about an outer edge of the lower primer bottom surface, wherein the flange is adapted to receive a polymer overmolding;

aligning the upper primer bottom surface and the lower primer bottom surface to align the lower primer aperture with the upper primer aperture to form an insert joint;

linking the upper primer bottom surface and the lower primer bottom surface to form the two piece primer insert;

providing a primer flash hole aperture extending through the lower primer aperture and the upper primer aperture;

providing a first polymer composition for molding a polymer ammunition cartridge;

molding from the first polymer composition a substantially cylindrical polymeric middle body having the two piece primer insert at a first end and a substantially cylindrical polymeric coupling region at a second end, wherein the first polymer composition extends over an outer surface of the two piece primer insert over the flange and extends over the interior surface of the substantially cylindrical coupling element into the primer flash hole aperture forming a flash hole, wherein the first polymer composition extends from the substantially cylindrical polymeric coupling region into the primer flash hole aperture;

forming a substantially cylindrical polymeric bullet-end component from a second polymer composition comprising a bullet aperture opposite a polymeric bullet-end coupling that mates to the substantially polymeric cylindrical coupling region; and

coupling the substantially cylindrical polymeric coupling region to the polymeric bullet-end coupling to form a propellant chamber that extends from the primer flash hole aperture to the bullet aperture.

14. The method of claim 13, wherein the upper primer insert portion, the lower primer insert portion or both are independently formed by metal injection molding, polymer injection molding, stamping, milling, molding, machining, punching, fine blanking, smelting, or any other method that will form insert portions that may be joined together to form a primer insert.

15. The method of claim 13, wherein linking is by threading, riveting, locking, friction fitting, coining, snap fitting, chemical bonding, chemical welding, soldering, smelting, sintering, adhesive bonding, laser welding, ultrasonic welding, friction spot welding, friction stir welding spin-welding, vibration-welding, ultrasonic-welding, laser-welding techniques or a combination thereof.

16. The method of claim 13, wherein the upper primer insert portion, the lower primer insert portion or both independently comprises a polymer, a metal, an alloy, or a ceramic alloy.

17. The method of claim 13, further comprises a flash hole groove that extends circumferentially about the upper primer aperture or the lower primer aperture.

18. The method of claim 13, wherein the upper primer insert portion and the lower primer insert portion independently comprise steel, nickel, chromium, copper, carbon, iron, stainless steel brass or a combination thereof.