U.S. patent number 3,682,098 [Application Number 05/000,290] was granted by the patent office on 1972-08-08 for explosive charge ignition system.
This patent grant is currently assigned to Messerschmitt-Bolkow-Blohm Gesellschaft mit beschrankter Haftung. Invention is credited to Johann Spies.
United States Patent |
3,682,098 |
Spies |
August 8, 1972 |
EXPLOSIVE CHARGE IGNITION SYSTEM
Abstract
An ignition system particularly for setting off an explosive
charge inclu an inductive connection, between an electrical
ignition system for the charge and a feed voltage source for
actuating the system, by means of transformer windings. The
electrical ignition system includes an electrical ignition element
which is actuated by the voltage induced in two coils, or
transformer winding sections, of the ignition system which are
wound in an opposite sense and arranged in series. The transformer
winding of the ignition system is harmonized with the transformer
winding having the feed voltage applied thereto and which may be
inductively coupled to the transformer winding of the ignition
system. The transformer winding having the feed voltage applied
thereto also comprises two coils, or winding sections, wound in an
opposite sense. The construction includes plug type connections,
for example in the form of a female member or bushing which is
adapted to receive a plug member or male part, the two parts having
corresponding spaced inductive coils which align in the plugged in
arrangement. The coils may also be formed on a flat plate in
side-by-side relationship so that when a transmitting set arranged
on one plate is superimposed on a receiving set on another plate,
the corresponding coils may be superimposed.
Inventors: |
Spies; Johann (Pfaffenhofen,
DT) |
Assignee: |
Messerschmitt-Bolkow-Blohm
Gesellschaft mit beschrankter Haftung (Muenchen,
DT)
|
Family
ID: |
5722177 |
Appl.
No.: |
05/000,290 |
Filed: |
January 2, 1970 |
Foreign Application Priority Data
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|
|
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Jan 11, 1969 [DT] |
|
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P 19 01 271.6 |
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Current U.S.
Class: |
102/206;
336/DIG.2; 336/83; 336/200 |
Current CPC
Class: |
H01F
38/14 (20130101); F41A 19/63 (20130101); Y10S
336/02 (20130101) |
Current International
Class: |
F41A
19/00 (20060101); H01F 38/14 (20060101); F41A
19/63 (20060101); F42c 011/04 (); F42c 011/00 ();
F42c 015/40 () |
Field of
Search: |
;336/DIG.2,206
;102/19.2,70.2 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Engle; Samuel W.
Assistant Examiner: Webb; Thomas H.
Claims
What is claimed is:
1. An ignition circuit system for inductive connection to energize
an igniter for an explosive charge comprising, in combination a
transformer, an ignition circuit including an electrically
energized igniter connected in series with a first winding of said
transformer including two first coils wound in respective opposite
directions and in series with each other; an energizing circuit
including a source of electric potential connected in series with a
second winding of said transformer including two second coils wound
in respective opposite directions and in series with each other;
and respective connection and mounting means independently mounting
portion of the circuit and selectively movable into cooperating
relation with each other with each second coil positioned adjacent
a correspondingly located respective first coil; the winding
direction of each second coil with respect to that of its
correspondingly located respective first coil being such that said
transformer windings are effectively coupled inductively when said
mounting means are in said cooperating relation with each other,
whereby to apply the potential of said source to said igniter to
energize said igniter.
2. An ignition circuit system, according to claim 1, wherein said
two first coils have a low ohmic resistance so as to maintain the
potential at opposite terminals of said igniter at the same value
to prevent accidental energization of said igniter by stray
electric fields, said two first coils thus constituting, when said
connection and mounting means are not in cooperating relation with
each other, an effective short circuit for said igniter.
3. An ignition, according to claim 1, wherein said first and second
windings of said transformer are dimensioned to produce a matching
of the impedance between said source and said igniter when said
connection and mounting means are moved into said cooperating
relation with each other.
4. An ignition circuit system according to claim 1, wherein said
first and second transformer winding coils comprise flat coils.
5. An ignition circuit system inductive connection, according to
claim 1, including respective magnetic material means shielding
each of said first and second coils against interfering magnetic
fields when said connection and mounting means are not in said
cooperating relation with each other; said magnetic material means
having a low magnetic resistance enhancing the inductive coupling
between said first and second winding of said transformer when said
connection and mounting means are moved into cooperating relation
with each other.
6. An ignition circuit system, as claimed in claim 1, in which said
first coils are arranged in axially spaced relation on one part of
an interengageable plug-in type connector, and said second coils
are arranged in corresponding axially spaced relation on the other
part of said interengageable plug-in type connector; each part of
said plug-in type connector constituting a respective one of said
mounting means; whereby, when said plug-in type connector has its
parts interengaged, each second coil is positioned in inductive
relation with its correspondingly located respective first
coil.
7. An inductive connection, according to claim 6, wherein said
plug-in type connector is of a coaxial type and includes a female
bushing part and a male plug part.
Description
SUMMARY OF THE INVENTION
This invention relates in general to ignition systems for
explosives and in particular to a new and useful inductive
connection between an electrical ignition system of an explosive
charge and a feed voltage source by means of transformer
windings.
Inductive connections for supplying the electrical ignition system
of powder charges with energy are known, for instance in connection
with missile launchers as indicated in U.S. missile, No. 2,640,417.
In this known device, a missile having a first transformer winding,
the electrical ignition system and the powder charge in the form of
a rocket propellant, is launched from a firing tube. The firing
tube has a second transformer winding connected to a suitable feed
voltage source and inductively coupled with the first transformer
winding in the firing position of the missile.
Even though the first transformer winding which is housed in the
missile is enclosed by a steel shell which shields it against
interferring magnetic fields, it is nevertheless possible to induce
voltages into this winding which is sufficient to ignite the rocket
propellent especially when the interfering magnetic fields are
strong. Such an undesired ignition of the propellant must be
avoided if only for safety reasons. When it is desired to use such
inductive connections for igniting not only missile propellants but
also explosive charges of projectiles or to furnish the energy for
such ignition, then an undesired ignition due to interferring
magnetic or electrostatic fields must be avoided under all
circumstances.
An object of the present invention is therefore to improve the
known inductive connections so that an undesired triggering of the
electrical ignition system is avoided with certainity. In
accordance with the invention, the transformer winding of the
ignition system consists of two coils which are wound in an
opposite sense and arranged in series. Because of the division of
the transformer winding into two coils arranged in series
electrically and wound in an opposite sense and which are arranged
for coupling inductively with two coils of the feed voltage source
which are wound in a corresponding manner, the effects of
interfering magnetic fields are cancelled out in the transformer
(receiver) winding connected with the ignition system so that no
undesired triggering of the ignition system because of such
interference can occur.
According to a feature of the invention, the electrical ignition
element of the ignition system is short circuited by the coils of
the transformer windings. The ohmic impedance value of the
transformer winding which is connected with the ignition system is
so low that an effective electrical short circuit of the electrical
ignition element occurs so that an undesired triggering due to
electrostatic charges is thus avoided with certainity. This is
required particularly for the storing of war heads which are
equipped with such an ignition system or the storing of explosive
charges having a disrupted inductive connection.
The transformer windings of the feed voltage source and the
transformer windings of the ignition system are dimensioned so that
a matching of the impedance between the feed voltage source and the
ignition system takes place. By such a design the transformer
windings required for the inductive transmission are utilized also
for the transformation of the output impedance of the feed voltage
source to the input impedance of the ignition system. This means,
for example, that even relatively low ohmic electrical ignition
elements can be triggered safely by means of a feed voltage source
having a high output impedance.
The inventive inductive connection is advantageously constructed in
a traditional manner as a coaxial plug connection with
concentrically arranged overlapping transformer windings. The
transformer windings may also be arranged as flat coils so that a
plug in type connection is formed by the superposition of two
touching plan parallel plates containing the respective sets of
transformer windings in the form of flat coils.
Accordingly, it is an object of the invention to provide an
improved inductive connection between an electrical ignition system
of an explosive charge and a feed voltage source by means of
transformer windings wherein the transformer winding of the
ignition system comprises two coils wound in an opposite sense and
connected in series and which advantageously includes an electrical
ignition element which is short circuited by the transformer
coils.
A further object of the invention is to provide an electrical
ignition system including an electrical ignition element which is
short circuited by transformer coils which are arranged to receive
induced voltage from a feed voltage source through a second set of
transformer coils, each transformer coil being divided into two
oppositely wound coils connected in series and dimensioned so that
a matching of the impedance between the feed voltage source and the
ignition system takes place.
A further object of the invention is to provide an inductive
connection which includes two transformer coils arranged in series
and wound in an opposite sense and advantageously incorporated as a
plug in type connection which when completed arranges one set of
coils over the other set, the plug in connection being either a
coaxial type or in the form of flat superimposed plates having the
respective coils.
A further object of the invention is to provide an inductive
connection particularly for the ignition system of an explosive
charge which is simple in design, rugged in construction, and
economical to manufacture.
The various features of novelty which characterize the invention
are pointed out with particularity in the claims annexed to and
forming a part of this specification. For a better understanding of
the invention, its operating advantages and specific objects
attained by its use, reference should be had to the accompanying
drawings and descriptive matter in which there are illustrated and
described preferred embodiments of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings:
FIG. 1 is an axial sectional view of a detached plug in type
inductive connection for an explosive charge constructed in
accordance with the invention;
FIG. 2 is a top plan view of a single one of a flat plate type plug
connection of another embodiment of the invention; and
FIG. 3 is a schematic electrical wiring diagram of the plug
connection.
GENERAL DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to the drawings in particular, the invention embodied
therein in FIG. 1, includes a plug connection for an inductive
connection between an electrical ignition system of an explosive
charge and its feed voltage source. In this embodiment the
inductive connection is preferably constructed in the manner of a
traditional coaxial plug connection which includes a bushing part
or female part 1 which carries, at two axially spaced locations,
two cylindrical coils 2 and 3. The coils 2 and 3 are electrically
connected together in series and are oppositely wound.
The bushing part 1 is arranged to receive a plug part or male part
4 which includes two cylindrical coils 5 and 6 which are arranged
at spaced axial locations corresponding in spacing to that of the
coils 2 and 3 and located so that they will be covered by the coils
2 and 3 of the bushing part when the plug connection is assembled.
The coils 5 and 6 are connected in series and are oppositely wound
in a manner similar to that of the coils 2 and 3.
In the embodiment indicated in FIG. 2, a plug connection is made by
two identical plate members only one of which, plate 7, is
indicated. The plate 7 carries two flat coils 8 and 9 which are
connected together in series and which are oppositely wound. The
other part (not shown) is constructed in a similar manner and
carries two additional flat coils (not shown) which are wound
correspondingly to the coils 8 and 9 and are connected in series
and are arranged so that they cover the coils 8 and 9 when the
additional plate is superposed on the plate 7.
A simplified electrical wiring diagram for the inductive connection
is shown in FIG. 3, and it includes an ignition system 10 having a
transformer winding 11 for operating an electrically actuated
ignition element 12. The transformer winding includes two coils 111
and 112 which are wound in an opposite sense and arranged in series
electrically. These coils correspond for example, to the coils 2
and 3 of FIG. 1. A feed voltage source 20 in an energizing circuit
22 acts upon a second transformer winding 21 which also comprises
two coils 211 and 212 which are wound in respective opposite
directions and connected together in series. Because the respective
coils 111 and 211 and 112 and 212 which communicate with each other
inductively are wound in the same sense, the voltages induced in
the coils 111 and 112 add up to a total voltage which safely
triggers the ignition element 12 when the ignition system 10 and
the feed voltage system 22 are connected with each other
inductively through transformer winding 11 and 21. Due to the low
ohmic resistance of transformer winding 11, when not inductively
coupled to transformer winding 21, this transformer winding 11,
with its sections 111 and 112, acts as a short circuit for the
ignition element 12, protecting the latter against energization by
stray electrostatic or electromagnetic fields.
By using suitable materials to form shields or shielding elements
13 and 14 the transformer windings 11 and 21 are shielded against
interfering magnetic fields when they are in the unassembled
condition through the action of the shields 13 and 14 which act as
magnetic circuits. In the assembled conditions these shielding
elements 13 and 14 favor the inductive coupling because the
magnetic impedance is relatively small for the magnetic flux which
developes between the transformer windings 11 and 21. The number of
windings of the transformer windings 11 and 21 are so harmonized
mutually that a matching of the impedance of the feed voltage
source 20 to the electrical ignition element 12, as a consumer of
the energy furnished by the feed voltage source 20, takes
place.
Besides the advantageous electrical properties of the inductive
connection such as insensitivity to interfering magnetic fields and
electrical short circuiting of the electrical ignition element in
the unassembled state of the plug connection, the arrangement
offers the additional advantage that it can be built so as to be
very strong and robust mechanically. The arrangement is such that
for certain applications in modern weapons technology explosive
charges directly connected to the plug part of the plug connection
can be triggered without damaging or even destroying the reusable
bushing part 1 even though there are considerable shock wave loads
which occur.
* * * * *