Ammunition and explosives – Cartridges – Case
Reexamination Certificate
1998-11-06
2001-03-27
Price, Thomas (Department: 3643)
Ammunition and explosives
Cartridges
Case
Reexamination Certificate
active
06205927
ABSTRACT:
FIELD OF THE INVENTION
The present invention pertains to an electric impulse cartridge or primer device for igniting explosive or pyrotechnic charges wherein the device is provided with improved high energy emission and high ignition rate combustible electrodes which significantly reduce the elapsed time from generation of an electrical firing signal to ignition of a charge in the device and an associated explosive or pyrotechnic charge.
BACKGROUND
This invention is related to the electrical or electrostatic discharge pyrotechnic cartridge and primer device inventions disclosed and claimed in my U.S. Pat. No. 5,235,127 issued Aug. 10, 1993 and my co-pending U.S. patent application Ser. No. 08/688,085 filed Jul. 29, 1996. The electrically fired primers or cartridges described in the above referenced patent and pending patent application provide certain advantages over conventional bridge wire type igniters or primers which are susceptible to the effects of unwanted or stray electromagnetic radiation, sometimes referred to as the high energy radio output (HERO) effect. Although the primer devices or cartridges disclosed and claimed in my prior patent and patent application provide certain advantages as set ford therein, there has been a continuing need to provide a cartridge or primer device which has a higher rate of energy output and a reduced firing cycle time. In the ignition of ordnance charges, for example, it is desirable to minimize the firing time once the ignition or firing signal has been transmitted to the ordnance apparatus. Moreover, the cost of simulated ordnance devices and the residue provided by prior art primer devices or igniters has also driven the effort to develop still further improvements in impulse cartridges or primer devices for use with ordnance charges and other pyrotechnic devices and wherein such primer devices may be reused or at least the material of which they are made can be recycled. It is to these ends that the present invention has been developed.
SUMMARY OF THE INVENTION
The present invention provides an improved electrically fired or ignited cartridge or primer device for providing ignition of a primer charge of explosive or pyrotechnic material which, in itself, may produce a useful concussion, visible light and noise effect or may be used to ignite additional explosive or pyrotechnic charges for simulating ordnance discharges. The cartridge may also be used in live ordnance devices for energizing or igniting same.
In accordance with one aspect of the present invention an electric cartridge or primer device is provided which is formed of a molded plastic body or case provided with a cavity for receiving a pyrotechnic or explosive composition. The cartridge is also provided with improved electrodes which are formed of compositions which provide for generation of a high rate of energy output in a minimum amount of time to ignite the pyrotechnic or explosive charge of the device, which in turn may be used to ignite additional charges or compositions.
In accordance with another aspect of the present invention the electrodes of the impulse cartridge may be formed of electrically conductive plastic or similar compositions which may be doped with conductive materials which improve the firing speed and the energy output from the electrodes into the associated charge of explosive or pyrotechnic composition. The electrode dopant materials also provide an electrical resistance value which is useful for identifying the particular type of cartridge or primer device in place in an ordnance system. The cartridge body may also be doped with materials which provide a predetermined electrical resistance to a low voltage pulse of predetermined voltage and/or frequency. Accordingly, a discrete low voltage interrogation pulse may be imposed on the device to measure the resistance and identify the particular cartridge.
In accordance with still another aspect of the present invention the cartridge electrodes may be formed of a conductive thermoplastic, such as ABS (acrylonitrile-butadiene-styrene) which is doped with combinations of combustible or explosive compositions selected from a group consisting of boron, molybdenum trioxide, magnesium, polytetrafluoroethylene, fluoroelastomers, barium chromate and potassium perclorate. Selected combinations of the dopants cumulatively amounting to approximately 20% to 80% of the electrode by weight, in combination with the ABS plastic, have been determined to provide a substantially reduced ignition time for the cartridge, in the range of ten milliseconds or less, while providing substantial caloric output to ignite the cartridge charge as well as associated charges which are to be ignited by the cartridge. Such electrodes are electrically conductive and also undergo chemical conversion in response to a high voltage electrical potential thereacross to release energy and initiate energy release by other materials in proximity to the electrodes. Accordingly, the electrodes may be considered combustible, are consumed in the conversion process and may be defined as pyroconductive elements.
In accordance with still a further aspect of the present invention, an impulse cartridge or primer device is provided with pyroconductive electrodes which are suitable for molding and may be molded in place in conjunction with molding the cartridge body using conventional injection molding processes.
Still further, the present invention contemplates the provision of an electric impulse cartridge or primer device which is provided with a molded pyroconductive electrode and a second pyroconductive electrode which may comprise a conductive “ink” or coating which may be printed on the device body and arranged in a pattern which facilitates a very high rate of ignition or energization of the device explosive charge composition.
Those skilled in the art will appreciate the above mentioned features and advantages of the invention together with other important aspects thereof upon reading the detailed description which follows in conjunction with the drawings.
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Akin Gump Strauss Hauer & Feld L.L.P.
Brown Randall C.
Martin Michael E.
Price Thomas
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