U.S. patent number 3,814,017 [Application Number 05/205,102] was granted by the patent office on 1974-06-04 for method and system arrangement for determining the type and condition of ammunition ready for firing.
This patent grant is currently assigned to Rheinmetall GmbH. Invention is credited to Gunter Backstein, Frank-Volker Spath.
United States Patent |
3,814,017 |
Backstein , et al. |
June 4, 1974 |
METHOD AND SYSTEM ARRANGEMENT FOR DETERMINING THE TYPE AND
CONDITION OF AMMUNITION READY FOR FIRING
Abstract
Method and system arrangement for determining the type and
condition of ammunition which is ready for firing and can be
detonated electrically wherein specific signals corresponding to
the type and the condition values are sent as correction signals to
a firing control computer processing the target data for
positioning a piece of ordnance and/or for setting a fuse of the
ammunition. The ammunition is electrically detonated by means of an
electric propellant charge ignitor connected between the case of
the ammunition and a centrally disposed contact insulated from the
case with all measuring and control signals being supplied to the
ammunition via the central contact.
Inventors: |
Backstein; Gunter (Meerbusch,
DT), Spath; Frank-Volker (Dusseldorf, DT) |
Assignee: |
Rheinmetall GmbH (Dusseldorf,
DT)
|
Family
ID: |
5789960 |
Appl.
No.: |
05/205,102 |
Filed: |
December 6, 1971 |
Foreign Application Priority Data
Current U.S.
Class: |
102/215;
89/28.05; 89/6.5 |
Current CPC
Class: |
F42C
19/12 (20130101); F42C 11/00 (20130101); F42C
21/00 (20130101); F42B 35/00 (20130101) |
Current International
Class: |
F42C
11/00 (20060101); F42C 19/00 (20060101); F42C
21/00 (20060101); F42C 19/12 (20060101); F42b
009/08 (); F42c 011/00 (); F42c 011/06 () |
Field of
Search: |
;102/7.2R,7.2P |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Feinberg; Samuel
Assistant Examiner: Webb; Thomas H.
Attorney, Agent or Firm: Craig and Antonelli
Claims
What we claim is:
1. A method for determining the type and condition of electrically
detonatable ammunition which is ready for firing from a piece of
ordnance including the steps of supplying successive electrical
signals to measuring and control circuits associated with the
ammunition, modifying the signals in accordance with the type and
condition of the ammunition, supplying signals corresponding to the
modified signals of the type and condition values of the ammunition
as correction signals to a firing control computer, supplying
target data signals to the firing control computer, and processing
the correction signals and target data signals to provide output
signals corresponding to at least one of a desired positioning for
the piece of ordnance for firing the ammunition and a desired
setting for a fuse of the electrically detonatable ammunition.
2. A method according to claim 1 and further including the steps of
supplying external correction signals to the firing control
computer, and positioning the piece of ordnance and setting the
fuse in accordance with the processed signals.
3. A method according to claim 1, wherein the steps of supplying
signals to the measuring and control circuits and supplying
modified signals of the type and condition values of the ammunition
includes applying the signals and modified signals through a single
insulated central contact of an electrical ignition primer for the
ammunition.
4. A method according to claim 3, wherein a part of the signals
supplied in succession are of opposite polarity to the remainder of
the signals.
5. A method according to claim 1, characterized in that the signals
for setting the fuse are in the form of a series of pulses, and
including the step of varying the number of pulses in accordance
with the correction signals and target data.
6. A method according to claim 1, characterized in that the signals
for setting the fuse are in the form of voltage pulses, and
including the step of varying the voltage levels in accordance with
the correction signals and target data.
7. A firing control system for determining the type and condition
of electrically detonatable ammunition which is ready for firing
from a piece of ordnance, comprising ammunition having circuit
means for sensing the magnitude of at least one parameter of the
ammunition, control circuit means and firing circuit means arranged
therein, each of said circuit means having a common lead and each
including blocking means for preventing a signal applied to one
circuit means from being applied to another circuit means, said
ammunition having the case thereof serving as an electrode and a
contact electrically insulated therefrom serving as another
electrode for detonation of the ammunition, a firing control
computer means for connection with said common lead of said circuit
means of the ammunition for supplying signals to the ammunition and
receiving signals therefrom indicative of the type and condition
thereof in the form of correction signals, said computer means
being responsive to the ammunition correction signals, external
correction signals and target signals supplied thereto for
providing output signals for at least one of positioning the
ordnance piece and for setting the control circuit means of the
electrically detonatable ammunition.
8. A firing control system according to claim 7 wherein said
computer means includes a firing control computer having connected
thereto sensing means, control means, external correction means and
target means, said sensing means and control means being arranged
for connection to said common lead of the ammunition.
9. A firing control system according to claim 8, wherein the
ammunition includes electrical ignition primer means in engagement
with the case of the ammunition, said primer means having said
electrically insulated contact centrally arranged therein, said
contact serving for connecting said common lead of said circuit
means to said computer means.
10. A firing control system according to claim 9, wherein said
electrical ignition primer means is in screw-threaded engagement
with the ammunition.
11. A system according to claim 9, wherein said firing circuit
means includes an electric propellant charge igniter and associated
blocking means in the form of a rectifier, said sensing circuit
means includes a temperature-responsive resistor and an electrical
device means for identifying the type of ammunition and associated
blocking means in the form of a rectifier having the same polarity
as the firing circuit rectifier, and said control circuit means
includes a projectile fuse which can be controlled
electrically.
12. A system according to claim 9, wherein said blocking means of
said firing circuit means is a four-layer diode.
13. A system according to claim 11, wherein the electrically
controllable projectile fuse includes a first switching circuit
means for activating the fuse, the associated blocking means being
in the form of a rectifier having opposite polarity relative to the
other blocking rectifiers.
14. A system according to claim 13, wherein the electrically
controllable fuse includes a second switching circuit means for
setting the fuse in accordance with the correction signals and
target signals supplied to said computer means, the associated
blocking means being in the form of a rectifier having the same
polarity as the rectifiers for the firing circuit and the measuring
circuit.
15. A system according to claim 14, wherein said control means of
said computer means includes pulse transmitter means connected to
the firing control computer and adapted to be selectively connected
to the switching circuit for setting the fuse for delivering pulses
the number of which varies in accordance with the firing control
computer output signal depending on the correction signals and
target data signals supplied to the firing control computer.
16. A system according to claim 7, wherein the sensing circuit
means determines the type of ammunition and includes electrical
elements for characterizing the type of ammunition, said elements
providing different correction signals according to the type of
ammunition.
17. A system according to claim 15, wherein an AND gate is
connected between the pulse transmitter and the fuse, the pulse
transmitter providing an input to the AND gate, and a firing button
providing another input to the AND gate such that the pulses reach
the fuse after the firing button has been actuated.
18. A system according to claim 14, wherein the fuse includes an
ignition means and the switching circuit means for setting the fuse
comprises a counting chain with a storage member connected on the
load side, a pulse generator and an acceleration-responsive switch,
the acceleration-responsive switch connecting the pulse generator
to the counting chain after the acceleration phase of the fired
ammunition, and wherein the pulse generator during its operating
period renders the ignition means operative via the counting chain
in accordance with the signal magnitude stored in the storage
member.
19. A system according to claim 14, wherein the fuse includes an
ignition means and the switching circuit means for activating the
fuse and for supplying power to the switching circuit means for
setting the fuse, said activating switching circuit means
comprising an ignition voltage section for supplying the ignition
current for the ignition means and a low voltage section for
supplying power to the fuse setting switching circuit means.
20. A system according to claim 19, wherein the ignition voltage
section comprises a capacitor and a rectifier connected in series
and the low voltage section comprises a capacitor with a Zener
diode connected in parallel and a resistor connected in series
therewith and a rectifier.
21. A system according to claim 20, wherein an active power source
is provided in parallel with the low voltage section, an
acceleration-responsive switch being connected between the active
power source and the switching circuit for setting the fuse such
that the active power souce only supplies the switching circuit
with power after the projectile has left the barrel of the
piece.
22. A system according to claim 15, wherein the measuring circuit
means for determining the type of ammunition includes electrical
elements for characterizing the type of ammunition, said elements
providing different correction signals according to the type of
ammunition.
23. A system according to claim 16, wherein an AND gate is
connected between the pulse transmitter and the fuse, the pulse
transmitter providing an input to the AND date, and a firing button
providing another input to the AND gate such that the pulses reach
the fuse after the firing button has been actuated.
24. A system according to claim 17, wherein the fuse includes an
ignition means and the switching circuit means for setting the fuse
comprises a counting chain with a storage member connected on the
load side, a pulse generator and an acceleration-responsive switch,
the acceleration-responsive switch connecting the pulse generator
to the counting chain after the acceleration phase of the fired
ammunition, and wherein the pulse generator during its operating
period renders the ignition means operative via the counting chain
in accordance with the signal magnitude stored in the storage
member.
25. A system according to claim 18, wherein the fuse includes an
ignition means and the switching circuit means for activating the
fuse and for supplying power to the switching circuit means for
setting the fuse, said activating switching circuit means
comprising an ignition voltage section for supplying the ignition
current for the ignition means and a low voltage section for
supplying power to the fuse setting switching circuit means.
26. A system according to claim 25, wherein the ignition voltage
section comprises a capacitor and a recitifer connected in series
and the low voltage section comprises a capacitor with a Zener
diode connected in parallel and a resistor connected in series
therewith and a rectifier.
27. A system according to claim 26, wherein an active power source
is provided in parallel with the low voltage section, an
acceleration-responsive switch being connected between the active
power source and the switching circuit for setting the fuse such
that the active power source only supplies the switching circuit
with power after the projectile has left the barrel of the piece.
Description
The present invention relates to a method and system arrangement
for determining the type and condition of ammunition which is
readied for firing and can be electrically detonated and for
controlling the positioning of the piece of ordnance which fires
the ammunition and/or the setting of the ammunition fuse.
In order not to reveal one's own position to the enemy, it is of
great importance to be accurate with the first firing of the weapon
without first misfiring or trying out the range of a gun. Thus, to
increase the accuracy of fire at the time of the shot it is known
to take into consideration external ballistic data, which affect a
projectile, such as cross winds. It has been found, however, that
this data alone is not sufficient to ensure an accurate striking of
the target at the time of the first shot. In addition, it is
already known to set fuses of ammunition made up into cartridges
located in the barrel of the piece of ordnance by an inductive
potential, a wire being wound around the barrel of the piece at the
position of a coil connected to the fuse. By a brief application of
voltage corresponding to the distance of the target, the fuse is
set.
Also, it is known that the muzzle velocity and therefore the
trajectory of a projectile alters depending on the powder
temperature and therefore attempts have been made to measure the
powder temperature, in order that it can also be taken into
consideration when positioning the piece. For this purpose, several
concentric, mutually insulated rings have been provided in the base
of the case, to which is connected an electric temperature
measuring element, located in the powder of the projectile
cartridge, by means of which the powder temperature can be
ascertained. However, these prior art attempts have not proven
successful.
The present invention provides a method and system arrangement
which makes it possible to take accurately into consideration the
condition of a projectile cartridge, i.e., the internal ballistic
properties of a projectile cartridge located in the cartridge
chamber of a customary piece of ordnance provided with an electric
firing device, at the time of adjustment of the positioning gear of
a piece and/or a projectile fuse. The condition of the ammunition
or the internal ballistic ammunition properties are characterized
by the powder temperature inside the projectile cartridge, since it
is known that the gas pressure alters with the powder temperature,
and therefore so does the muzzle velocity of a projectile. Also,
with the method according to the invention and the system
arrangement, the type of ammunition, for example, explosive
incendiary projectiles, hard core or hollow charge projectiles with
time fuses, impact detonators or proximity fuses, whose muzzle
velocities can likewise differ from each other can be
determined.
The method according to the invention includes the steps of
providing successive electrical signals to ammunition which is
ready to be fired by means of measuring and control instruments
connected to the firing control computer, which signals are altered
in accordance with the type and condition of the ammunition and
then supplied by appropriate connections to the measuring and
control circuits associated therewith for application to the firing
control computer as correction signals and in combination with the
target data supplied to the computer bring about an appropriate
positioning of a piece of ordnance and/or setting of a fuse of the
ammunition which is ready to fire. With this method, it is possible
to determine the type and the condition of the ammunition located
in the cartridge chamber of a piece and to take this into
consideration when positioning the piece and/or setting the fuse.
Thus, the positioning of the piece and the setting of the fuse can
take place continuously depending on the data ascertained or just
once, immediately before the firing of a projectile.
In the method according to the invention all the signals are
preferably sent via a single, insulated central contact of a
threaded electrical-ignition primer, which is screwed into the
ammunition, at least a part of the consecutive signals being of
opposite polarity.
According to an advantageous development of the method, the signals
for setting the fuse are in the form of a series of pulses, the
number of which is determined by the control device depending on
the correction signals and target data. Alternatively, it is also
possible in accordance with the present invention for the signals
for setting the fuse to be in the form of voltage pulses, whose
voltage level is determined by the control device depending on the
correction signals and target data.
For carrying out the method according to the invention, a system
arrangement is utilized which is characterized in that in the
ammunition a firing circuit, a measuring circuit and a control
circuit are provided which by means of a common lead can be
connected to measuring and control devices connected to the firing
control computer, electrical blocking means being provided between
the switching circuits for separating the signals intended for the
individual circuits, and in that the firing control computer has
inputs for the correction signals coming from the ammunition which
is ready to be fired and for the input target data and the external
correction data, as well as outputs for the signals for positioning
the piece of ordnance and/or setting the fuse.
According to an advantageous embodiment of the system arrangement
it is provided that the common lead for the firing circuit, the
measuring circuit and the control circuit is connected to the
firing control computer via a single, insulated central contact of
a threaded electrical ignition primer. By means of this connection,
it is possible to use the method and arrangement according to the
invention even in conventional pieces of ordnance having electrical
firing, the connection between the projectile fuse and the primer
being made by plug contacts on screwing in the threaded primer and
inserting the projectile fuse into the case.
According to a further feature of the invention, the firing circuit
includes an electrical propellent charge igniter having an
associated blocking means in the form of a rectifier such as a
four-layer diode and the measuring circuit includes a temperature
responsive resistor and an electrical element for identifying the
type of ammunition. The measuring circuit is provided with
associated blocking means in the form of a rectifier having the
same polarity as the firing circuit rectifier. The control circuit
is provided with a projectile fuse which can be controlled
electrically and preferably includes a switching circuit for
activating the fuse, the associated blocking means in the form of a
rectifier having opposite polarity relative to the other rectifiers
and another switching circuit for setting the fuse depending on the
correction signals and target data wherein the associated blocking
means for this circuit is in the form of a rectifier having the
same polarity as the rectifiers for the firing circuit and the
measuring circuit.
In accordance with the present invention, by means of the
four-layer diode, the measuring voltage, which measures the powder
temperature by the change of the temperature-responsive resistor,
for example, a thermistor, and which indicates the type of
projectile with the aid of an element for identifying types of
ammunition, is prevented from firing the propellent charge igniter
since the four-layer diode becomes conductive only with a voltage
substantially higher than the measuring voltage. In the direction
in which the control circuit for setting the projectile fuse is
conductive, the measuring and firing circuits are blocked by the
rectifiers of opposite polarity. The measuring and controlling thus
occurs by applying signals of opposed polarity, the ignition of the
firing charge occurring with simultaneous destruction of the
measuring circuit.
According to a further feature of the invention a pulse transmitter
is provided, which is connected to the firing control computer and
which can be connection to the switching circuit for setting the
fuse and delivers pulses, the number of which is determined by the
firing control computer depending on the correction signals and
target data supplied to the firing control computer.
In order to determine the type of ammunition, in the arrangement
according to the invention, switching elements are provided for
characterizing the type of ammunition, which switching elements
produce different correction signals according to the type of
ammunition.
According to a further feature of the invention, the pulse
transmitter is connected to the fuse with the interposition of an
electrical gate circuit of the "AND" type, the other input of the
gate being connected to the firing button, such that the pulses
reach the fuse only after the firing button has been actuated.
In order to be able to carry out the setting of the fuse in an
advantageous manner depending on the correction signals and the
target data, the switching circuit for controlling the fuse has a
counting chain with a storage element connected on the load side
and a pulse generator, as well as an acceleration-responsive
switch, which switch connects the pulse generator to the counting
chain after the accelerating phase, so that during its operating
period the pulse generator renders the ignition element operative
by means of the counting chain while taking into consideration the
value stored in the storage element. The switching circuit for
activating the fuse and for supplying power to the switching
circuit for setting the fuse also comprises an ignition voltage
section for supplying the ignition current for the ignition element
and of a low voltage section for supplying power to the switching
circuit for setting the fuse. The ignition voltage section
preferably comprises a capacitor and a rectifier connected in
series and the low voltage section comprises a capacitor with a
zener diode connected in parallel and a resistor connected in
series therewith and a rectifier.
In a further development of this system arrangement, an active
power source is arranged in parallel to the low voltage section,
which can be connected to the switching circuit for setting the
fuse by means of an acceleration-responsive switch in such a way
that the active power source only supplies the switching circuit
with power after the projectile has left the barrel of the
piece.
It is therefore an object of the present invention to provide a
method and system arrangement for determining information of the
type and condition of ammunition which is readied for firing and
for controlling the positioning of a piece of ordnance and/or
setting the fuse of the ammunition in accordance with the
ammunition information as well as target and external correction
data which overcomes the drawbacks of prior art arrangements.
It is another object to provide electrical ignition primer means
which can be secured to conventional ammunition and which includes
a common lead for all signals to and from the ammunition.
It is a further object to provide ammunition which is electrically
detonatable via the cartridge case serving as one pole for the
circuit and a contact electrically insulated therefrom as the other
pole.
These and further objects, features and advantages of the present
invention will become more obvious from the following description,
when taken in connection with the accompanying drawings which show,
for purposes of illustration only, several embodiments in
accordance with the present invention, and wherein:
FIG. 1 shows diagrammatically a projectile cartridge connected to a
firing control computer, the cartridge being located in a barrel of
a piece of ordnance;
FIG. 2 is a diagrammatic circuit diagram of an activating
device;
FIG. 3 is a graph showing the sequence of the measuring and control
signals when using a series of pulses for setting the fuse;
FIG. 4 is a graph showing the current flow curves for various types
of projectile when using different capacitors as elements for
recognizing the type of ammunition;
FIG. 5 is a graph showing the sequence of the measuring and control
signals when using negative voltage pulses for setting the fuse;
and
FIG. 6 is a graph showing current flow curves for various types of
projectile when using different resistors as elements for
recognizing the type of ammunition.
Referring now to the drawings wherein like reference numerals
designate like parts throughout the several views and more
particularly to FIG. 1, there is shown a projectile cartridge 2
with a case 2a and a projectile 2b located in a cartridge chamber
1a of a barrel 1 of a piece of ordnance. The projectile cartridge
is secured in the barrel 1 of the piece by a breech-block mechanism
part 3. A threaded electrical ignition primer 4 is screwed into the
case 2a and is provided with a centrally disposed contact 6 which
serves as an electrical pole or electrode and is electrically
insulated by a layer of synthetic material 5. The central contact 6
is connected by a diode 7 to a temperature sensing element 9, for
example, a thermistor, and to an element for characterizing the
type of ammunition in the form of a capacitor 8a, connected in
parallel thereto, and to the threaded electrical ignition primer 4
which is in electrical contact with the case 2a. The case 2a serves
as the other electric pole or electrode for the ammunition circuits
and is generally at ground potential. In parallel with this circuit
is a series connection of a four-layer diode 11 and an electrical
propellent charge igniter 12, the igniter being surrounded by a
propellent charge powder 10. The central contact 6 is also
connected by plug and socket connections 14 to a projectile fuse
15, which can be a delay fuse or time fuse, a proximity fuse or an
impact detonator.
The fuse 15 includes a fuse activating device 39, which receives a
signal via the blocking device 13 for making the ammunition live
only when it has been inserted in the cartridge chamber 1a of the
barrel 1 of the piece. In the present embodiment an electronic time
fuse is illustrated which is set by a firing control computer, as
will be described hereafter, and includes a counting chain 36 with
a storage device 38 connected on the load side and a pulse
generator 35, preferably in the form of a quartz crystal timer. The
counting chain 36 is connected to the central contact 6 by a diode
33 and the plug and socket contacts 14 and is controlled by the
pulse generator 35 such that a signal is sent to an ignition device
37, when the specified time for firing the projectile has been
reached.
The activating device 39 serves for supplying power to both the
pulse generator 35 as well as the counting chain 36 and the storage
device 38. In addition, it serves for supplying the ignition
current for the ignition device 37. According to a preferred
embodiment, the activating device 39 is divided into an ignition
voltage part 39a for supplying the ignition current for the
ignition member 37 and into a low voltage part 39b for supplying
power to the pulse generator 35, the counting chain 36 and the
storage device 38. As shown in FIG. 2, the low voltage part 39b
includes a capacitor 41 connected in parallel with a Zener diode
42, which capacitor 41 is charged via a resistor 43 and the
rectifier 13b to the voltage, for example, of about 15V,
illustrated by the first part of the signal c in FIG. 3. The
ignition voltage part 39a, consisting of the capacitor 40, is then
charged by the recitfier 13a to the voltage of approximately 100V
illustrated by the second part of the signal c. Since the Zener
diode 42 becomes conductive at a voltage above 15V, the voltage at
the capacitor 41 is independent of the higher ignition voltage and
remains at the former value.
In accordance with a further development of this embodiment, a
power source in the form of an electrical battery 44 is connected
in parallel with the low voltage capacitor 41. The battery 44 is
intended for supplying power to the pulse generator 35, the
counting chain 36 and the storage device 38, after the projectile
2b has left the barrel 1 of the piece. For this purpose, an
acceleration responsive switch 34 is interposed, which makes the
connection only when the acceleration phase has ended. In this
manner the constant connection of the battery 44 to the pulse
generator, the counting chain 36 and the storage device 38
resulting in discharge of the battery is avoided. Also, during the
high acceleration after the ignition of the propellent charge, the
pulse generator 35 may not work properly and therefore, according
to the invention, the pulse generator 35 is connected to the
counting chain 36 by another acceleration-responsive switch 34 only
after the acceleration phase. It should be noted that the ignition
voltage does not of necessity have to be supplied from outside. It
can also be produced by means of induction by the low voltage part
39b. Thus, it is possible to avoid providing a source of ignition
voltage on the piece, of course due to this the fuse becomes more
complicated.
It should be noted that in a projectile with, for example, an
impact detonator, the activating device 39 can consist of a simple
switch member, which makes the fuse live. However, it can also
consist of a power storing device, to which the necessary power is
supplied from outside by a power supply device. Depending upon the
requirements, it can also be an active power source which is
switched on from outside or of a combination of both.
As shown in FIG. 1, the central contact 6 is connected to a
change-over switch 20 by a contact 17 insulated in a layer of
synthetic material 16 provided in the breechblock mechanism 3. This
change-over switch has an input II for the ammunition activating
signal, which is produced in a generating device 40 of conventional
construction which provides either a pulse, which switches on the
activating device 39 or a voltage signal of a certain duration,
which charges the activating device 39. Another input I of the
change-over switch 20 is connected to the firing control computer
18 by a measuring and control device 27 for recognizing the type of
ammunition and a temperature measuring and control device 28. The
firing control computer 18 serves for actuating the positioning
mechanism 22 for the piece of ordnance and for setting the fuse 15
depending on the data supplied, i.e., depending on the external
correction data supplied by transducer device 26, on the target
data supplied by the transducer device 25, on the type of
ammunition supplied by the device 27 and on the powder temperature
supplied by the device 28. It should be noted that transducer
device 25, 26 and measuring devices 27 and 28 are all of
conventional construction for performing the desired operations in
converting input data into signals utilizable as inputs for the
computer 18. The determining values for the fuse 15 are converted
by means of a pulse transmitter 32 into a series of pulses, the
number of which is determined by the correction signals and target
data supplied to the computer 18 which provides an output to
transmitter 32. These pulses are preferably sent to the ammunition
via an AND gate 31 and the change-over switch 20. The second input
of the gate 31 is connected to the firing button 21, so that the
pulses from the pulse transmitter 32 are only passed on to fuse 15
after the firing button 21 has been pressed.
According to a further embodiment (not shown) the determining
values for the fuse 15 are expressed by negative voltage pulses d'
as shown in FIG. 5, the voltage level of which is determined by the
correction signals and target data supplied, the different voltage
level of the illustrated voltage pulses representing the changing
computer output in accordance with the values of the correction
signals and target data which are continuously altering up to the
moment of firing.
The first pulse coming from the gate 31 is further sent via a delay
device 30 to the propellent charge ignition device 29, which
provides an output signal e, as shown in FIGS. 3 and 5, in the form
of a greatly increased voltage to the electric propellent charge
igniter 12. The ignition voltage is of a level which causes the
four-layer diode 11 to conduct, the diode only becoming conductive
at this voltage. Obviously, the four-layer diode 11 may be replaced
by another equivalent device, which has a blocking action in one
direction and becomes conductive at a predetermined voltage. It
should be noted that the electrical delay device 30 is only
necessary if the time between the actuation of the electric
propellent charge igniter 12 and the ignition of the propellent
charge is too short for sending the fuse setting pulses to the
fuse.
In operation, upon placing the ammunition in the ammunition chamber
of the piece of ordnance and switching on the firing control
computer, the change-over switch 20 alternately establishes a
connection between one of its inputs I and II and its output III,
beginning with a connection between the input I and the output III.
At this moment a voltage is applied via the diode 7 to the
measuring circuit consisting of the capacitor 8a and the resistor
9. This voltage corresponds to the signal a in FIG. 3 and is
supplied by the measuring and control device 27 which, for example,
may include suitable means for providing the signal at the instance
of switching of the change-over switch. As indicated previously,
the capacitance of the capacitor 8a is chosen in accordance with
the type of ammunition, so that for different types of ammunition
the different charging currents shown in FIG. 4 result. The device
27 also includes means for recognizing the type of ammunition in
the form of a current measuring member 27b and a delay member 27a
connected in such a manner that the charging current is measured a
certain time T after switching on the voltage, so that according to
the type of ammunition a current I.sub.1, I.sub.2, I.sub.3 of
varying magnitude is measured (FIG. 4) and a signal indicative
thereof is supplied to the firing control computer 18, which uses
this value for setting the fuse 15. After the charging current
through the capacitor 8a dies away, there flows through the
thermistor 9 only the constant current I.sub.4, whose value depends
on the instantaneous resistance of the thermistor 9. The
temperature measuring device 28 measures this current and provides
an output signal indicative of the temperature of the propellent
charge which is fed to the firing control computer 18. As shown in
FIG. 3, the two signals a and b have a positive polarity at the
central contact 6, whereas the signal c, which is produced by the
generating device 40, has a negative polarity. This signal c is fed
to the activating device 39 for charging the capacitors when the
change-over switch 20 produces the connection between the input II
and output III in accordance with its timed switching
characteristics. After a predetermined time interval the
change-over switch 20 switches back to the connection between the
input I and the output III and the signals a and b are again
supplied to the firing control computer 18 for updating the
computer. After another switching to the connection between the
input II and the output III, a connection from the generating
device 40 is again made to the activating device 39. It should be
noted that the alternating input of positive and negative signals
a, b, c can be used to return the counting chain to a definite
starting position, so that these signals do not influence the
setting of the fuse.
By pressing the firing button 21 at the point A, as shown in FIG.
3, the change-over switch 20 is instantaneously switched back to
the connection between the input I and the output III. A signal is
thus provided to the gate 31 which enables the gate and passes the
pulses d (FIG. 3) from the pulse transmitter 32 to the counting
chain 36 by way of the change-over switch 20, the plug and socket
connections 14 and the diode 33. The first pulse is also fed with a
predetermined delay which is determined by the delay device 30 or
by the ignition delay of the propellent charge to the propellent
charge ignition device 29 which provides a greatly increased
voltage output signal e to the electric propellent charge igniter
12 through the four-layer diode 11 which is conductive at this
voltage. Thus, the ignition of the propellent charge occurs and the
projectile is accelerated in the barrel of the piece. During the
acceleration phase, the acceleration-responsive switch 34 is opened
so that the pulse generator 35 is separated from the counting chain
36. After the projectile leaves the barrel, the acceleration ceases
and the pulse generator 35 is connected to the counting chain 36.
From this point on the pulse generator 35, the counting chain 36
and the storage device act upon each other in a well-known manner
such that after a period corresponding to the number of pulses
supplied, a signal is sent to the ignition device 37, which
explodes the projectile.
The aforedescribed method of operation relates to a projectile with
a time fuse. However, different types of fuses may be utilized. For
example in a projectile with a proximity fuse, the signal coming
from the pulse counter 36 does not cause the projectile to explode,
but rather activates the actual proximity fuse a short distance
from the target, so that a premature explosion by the response of
the proximity fuse to objects other than the target is thus
avoided.
It should be noted that the member 8a for recognizing the type of
ammunition does not necessarily have to be a capacitor, as shown,
but may be replaced by other electrical members, such as, for
example, by a resistor or an inductance or a combination of these.
When using different resistors as the member for recognizing the
different types of ammunition and assuming that the powder
temperature alters with the time T, according to the type of
ammunition, for example, the current flow curves I'.sub.1,
I'.sub.2, I'.sub.3 illustrated in FIG. 6 result.
Under certain circumstances, the gate 31 can be dispensed with,
such that the pulses from the pulse transmitter 32 are fed to the
fuse 15 after each occurrence of the activating signal c. In this
manner, the setting of the fuse would alter continuously until the
moment of firing. However, care must be taken in this type of
operation to ensure that the last pulse sequence before firing
effects the final setting of the fuse.
Obviously, many modifications and variations of the present
invention are possible in the light of the above teachings. It
should therefore be understood that within the scope of the
appended claims, the invention may be practiced otherwise than as
specifically described.
* * * * *