U.S. patent number 3,601,054 [Application Number 04/807,727] was granted by the patent office on 1971-08-24 for method and apparatus for electromagnetically initiating ordnance.
This patent grant is currently assigned to Unidynamics/Phoenix Unidynamics/Phoenix. Invention is credited to William O. Christianson.
United States Patent |
3,601,054 |
Christianson |
August 24, 1971 |
METHOD AND APPARATUS FOR ELECTROMAGNETICALLY INITIATING
ORDNANCE
Abstract
In order to obviate the necessity for using firing pins or
electrical probes for initiating ammunition, a cluster of
conductors are enclosed within a mass of pyroignition material, and
means are provided to subject the cluster of conductors to control
electromagnetic radiation such that they are heated into an
incandescent state to ignite the pyroignition material.
Inventors: |
Christianson; William O. (N/A,
AZ) |
Assignee: |
Unidynamics/Phoenix;
Unidynamics/Phoenix (AZ)
|
Family
ID: |
25197061 |
Appl.
No.: |
04/807,727 |
Filed: |
March 17, 1969 |
Current U.S.
Class: |
102/200; 102/201;
89/28.05 |
Current CPC
Class: |
F42B
5/08 (20130101); F41A 19/63 (20130101); F42C
19/12 (20130101) |
Current International
Class: |
F42B
5/08 (20060101); F42B 5/00 (20060101); F41A
19/00 (20060101); F41A 19/63 (20060101); F42C
19/00 (20060101); F42C 19/12 (20060101); F42B
009/08 () |
Field of
Search: |
;89/135,28 ;42/84
;102/46,70.2 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Stahl; Robert F.
Claims
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 energy.
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.
Description
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 of firing 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 1
packed within a case 2 is shown in cross section as disposed within
a barrel 3. The illustration of cased ammunition 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 5 is in
operation, is coupled through a conventional wave guide 8 to an
antenna horn disposed within the ordnance piece as represented in
FIG. 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 well-known 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 point that the upper portion 15 of the
inner casing 11 is parabolic 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 efficiency, 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 gigaHertz, 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.
* * * * *