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Publication numberUS3601054 A
Publication typeGrant
Publication dateAug 24, 1971
Filing dateMar 17, 1969
Priority dateMar 17, 1969
Publication numberUS 3601054 A, US 3601054A, US-A-3601054, US3601054 A, US3601054A
InventorsChristianson William O
Original AssigneeUnidynamics Phoenix
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Method and apparatus for electromagnetically initiating ordnance
US 3601054 A
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Description  (OCR text may contain errors)

United States Patent inventor William 0. Christianson [56] References Cited Lllchfield Park, UNITED STATES PATENTS P 969 2,459,854 1/1949 Swift, Jr 89/37 x Flled d r 2,640,417 6/1953 Bjork et al. 1 102/46 x V: hoe 3,177,651 4/1965 Lawrence... 102/702 ux Assignee 1; yu l? 3,351,016 11/1967 Simpson 102/702 6 3,362,329 1/1968 Epstein 102/702 Primary Examiner-Robert F. Stahl METHOD AND APPARATUS FOR Attorney-Drummond, Cahill & Phillips ELECTROMAGNETICALLY INITIATING gmwing ABSTRACT: In order to obviate the necessity for using firing pins or electrical probes for initiating ammunition, a cluster of [1.8. CI 102/46, conductors are enclosed within a mass of pyroignition materi- 89/28, 102/702 R al, and means are provided to subject the cluster of conduc- Int. Cl F42b 9/08 tors to control electromagnetic radiation such that they are Field of Search 89/135, 28; heated into an incandescent state to ignite the pyroignition 42/84; 102/46, 70.2 material.

Patented Aug. 24, 1971 350L054 BE- E INITIATION COMMAND POWER l POWER SUPPLY (MODULATOR) OSC'LLATQR INVENTOR. WILLIA M O. CHRISTIANSON ATTORNEYS METHOD AND APPARATUS FOR ELECTROMAGNETICALLY INITIATING ORDNANCE This invention relates to ordnance and, more particularly, to a method and apparatus for initiating ammunition and the like.

The devices presently used for initiating the ammunition of the larger ordnance pieces may be classified broadly as either firing pins or electrical probes. Firing pins and electrical probes, however, continue to display a disturbing tendency to fail. In particular, when used with caseless ammunition, firing pins and electrical probes have been observed to be subject to severe and rapid deterioration such that failure occurs at a rate intolerable in modern warfare.

It is a general object of this invention to provide means for reliably initiating ammunition.

It is a further object of this invention to provide such means without the use offiring pins or electrical probes.

It is a more specific object of this invention to provide initiating means utilizing controlled electromagnetic radiation to heat a cluster of conductors to incandescence.

These and other objects are achieved, according to one aspect of the invention, by disposing a cluster of conductors, each cut to a predetermined length, within a mass of pyroignition material and subjecting the cluster of conductors to'electromagnetic energy preferably at the frequency at which the individual conductors are one-half wavelength. The high current coupled into the conductors quickly heat them into an incandescent state to initiate the pyroignition material surrounding them.

The subject matter of the invention is particularly pointed out and distinctly claimed in the concluding portion of the specification. The invention, however, both as to organization and method of operation, may best be understood by reference to the following description taken in connection with the accompanying drawings of which:

FIG. 1 is a schematic representation of the firing system; and

FIG. 2 is a cross-sectional detail of the ignitor.

Referring now to FIG. 1, an ammunition round including propellant l packed within a case 2 is shown in cross section as disposed within a barrel 3. The illustration of cased ammu nition is merely exemplary, and it will be understood that the invention is equally applicable to ordnance pieces using caseless ammunition. An ignitor 4 is contained within a coaxial recess in the base of the case 2.

A power oscillator 5, such as a klystron, magnetron or the like, is modulated by selectively energizing its power supply 6 in the manner well known in the radar and high frequency engineering arts. The power supply 6 may be automatically or manually energized and deenergized by any convenient means suitable to the particular operating environment as represented by the block labeled initiation command in FIG. 1.

Electromagnetic energy, generated when the power oscillator is in operation, is coupled through a conventional wave guide 8 to an antenna horn disposed within the ordnance piece as represented in H0. 1. Thus, the antenna horn 9 directs the electromagnetic energy, through an electromagnetic window" 10, into the ignitor 4.

The construction of the ignitor 4 is shown more clearly in FIG. 2. A mass of pyroignition material 10 is packed within an inner casing 11 and an outer case comprising a cap 12 and a cover 13. The cover 13 must pass electromagnetic energy without significant attenuation and, therefore, should, like the window 10 of FIG. 1, be composed of any one of the wellknown materials possessing'the requisite properties.

A cluster of conductor sections 14 is generally centrally disposed within the pyroignition material 10 as best shown in FIG. 2. Typically, the cluster comprises a plurality of metallic wires, for example, aluminum or pyrofuse wires, cut to substantially the same predetermined length. Their function will be described below. It may also be observed at this oint that the upper portlon 15 of t e inner casing 11 is para olic and consists of a material, such as carbon or metal, which efficiently reflects electromagnetic waves.

Referring again to FIG. 1, as well as FIG. 2, to initiate the pyroignition material 10, the initiation command device 7 is activated to energize the power supply 6 thereby bringing the power oscillator 5 into operation. Electromagnetic energy from the power oscillator 5 is coupled through the wave guide 8 to the antenna horn 9 from which it is directed through the window 10 and the cover 13 to the ignitor. The electromagnetic energy passes through the pyroignition material 10 and is reflected from the parabolic surface 15 of the inner casing 11 to focus on the conductor cluster 14. The resulting currents developed in the individual conductors of the cluster quickly heat them into an incandescent state to initiate the pyroignition material 10 which, in turn, initiates the propellant.

For maximum efiiciency, it will be understood that the conductive wire cluster 14 will be centered at the focus of the parabolic reflector 15. Further, each of the conductors in the cluster 14 will have been cut to a length which is nominally one-half wavelength at the frequency of the electromagnetic energy directed at the cluster. For example, for a frequency of 13 gigaI-Iertz, this length is approximately 0.5 inch. Adjustment of the sensitivity of the conductor cluster can be changed by varying the wire diameter and/or the material. The dimensions of the parabolic reflector 15, the antenna horn 9,

etc., may also depend upon the frequency, but these are matters well known in the radar engineering art and need not be treated at length here.

While the principals of the invention have now been made clear in an illustrative embodiment, there will be immediately obvious to those skilled in the art many modifications of structure, arrangement, proportions, the elements, materials, and components used in the practice of the invention which are particularly adapted for specific environments and operating requirements without departing from those principals.

I claim:

1. Apparatus for igniting pyroignition material comprising:

A. a cluster of electrical conductors disposed in heat-conducting relationship with the pyroignition material;

B. a source of electromagnetic energy;

C. means for exposing said cluster of conductors to said electromagnetic energy;

D. said electrical conductors are of predetermined substantially equal lengths; and

E. said electromagnetic energy has a frequency such that the predetermined lengths of said conductors is substantially one-half wavelength.

2. The apparatus of claim 1 which further includes means for selectively activating said course of electromagnetic ener- 3. The apparatus of claim 2 in which the pyroignition material is contained within a housing, said housing including a first side composed of a material exhibiting the properties of an electromagnetic window.

4. The apparatus of claim 3 in which said housing further includes a second side disposed opposite said first side, said second side comprising a paraboloid of electromagnetically reflective material whereby the electromagnetic energy is focused on said cluster of conductors.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US2459854 *Apr 18, 1946Jan 25, 1949Swift Jr Willard EGrenade projector
US2640417 *Dec 18, 1946Jun 2, 1953Us Sec WarIgnition safety device for induction fired rockets
US3177651 *Jan 18, 1962Apr 13, 1965United Aircraft CorpLaser ignition
US3351016 *Dec 10, 1965Nov 7, 1967Universal Match CorpExplosive arming and firing system
US3362329 *Dec 10, 1963Jan 9, 1968Sidney EpsteinElectro-explosive devices
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US5668342 *Dec 7, 1995Sep 16, 1997Discher; Stephen R. W.Apparatus and method for detection and neutralization of concealed explosives
US6152039 *Sep 4, 1991Nov 28, 2000Royal Ordnance PlcInitiation of propellants
US6591753Oct 11, 2000Jul 15, 2003Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V.Propellant device for pipe weapons or ballistic projection
US7775145Aug 2, 2007Aug 17, 2010Xtreme Ads LimitedSystem for neutralizing explosive and electronic devices
US7775146Feb 12, 2008Aug 17, 2010Xtreme Ads LimitedSystem and method for neutralizing explosives and electronics
US7784389 *Mar 20, 2006Aug 31, 2010Technology Patents, LlcAnti-terrorist system
US7958809Aug 13, 2010Jun 14, 2011Xtreme Ads LimitedMethod for neutralizing explosives and electronics
US8250961Jul 8, 2010Aug 28, 2012Technology Patents, LlcAnti-terrorist system
US8561515Dec 20, 2012Oct 22, 2013Xtreme Ads LimitedMethod for neutralizing explosives and electronics
US8683907Mar 14, 2013Apr 1, 2014Xtreme Ads LimitedElectrical discharge system and method for neutralizing explosive devices and electronics
DE2255140A1 *Nov 10, 1972May 24, 1973France EtatZuendvorrichtung mit elektrischer ausloesung
DE102009006079A1Jan 26, 2009Jul 29, 2010Oao Znjj "Burevestnik"Shot load igniting device for use in projectile chamber of artillery system, has coaxial apparatus whose part is provided at sides of chamber, and transmission source provided in frequency region, where chamber forms vertical shaft
DE202009014949U1Jan 26, 2009Oct 7, 2010Oao Znjj "Burevestnik"Einrichtung zur Zündung der Wurfladung in der Geschosskammer eines Artilleriesystems mit hülsenloser Ladung
EP1067354A1 *Jun 19, 2000Jan 10, 2001Giat IndustriesInitiating device for an explosive charge
EP1334327A2 *Sep 28, 2001Aug 13, 2003Superior Ballistics, Inc.Firearm cartridge and case-less chamber
WO1993005356A1 *Sep 4, 1991Mar 18, 1993Royal Ordnance PlcThe initiation of propellants
WO1994021980A1 *Mar 16, 1994Sep 29, 1994Jacques DavidFiring a composition with a microwave generator________________
WO1998036235A1 *Feb 12, 1998Aug 20, 1998Anthony Keith BrownMethod and apparatus for the remote clearance of explosive devices
WO2001027553A1 *Oct 11, 2000Apr 19, 2001Eisenreich NorbertPropellant device for pipe weapons or ballistic projection
WO2005043069A1 *Oct 27, 2004May 12, 2005Aknine GerardEmp firing mechanism for large caliber firearms and artillery
Classifications
U.S. Classification102/200, 89/28.5, 102/201
International ClassificationF41A19/00, F42C19/12, F41A19/63, F42C19/00, F42B5/08, F42B5/00
Cooperative ClassificationF42B5/08, F42C19/12, F41A19/63
European ClassificationF41A19/63, F42C19/12, F42B5/08