US3688701A - Command fuze - Google Patents

Abstract

The shell includes RF detector circuitry, a pulse counter, and a firing circuit for a detonator which may be caused to explode during flight when it receives a predetermined number of radio pulses transmitted by ground command, or when, after receiving the predetermined number of pulses, the shell also receives a radio fire pulse by ground command. The fire pulse may be sent out by differential ranging system which continuously checks the distance to the shell and to the target and sends out the fire pulse when the distance is reduced to the predetermined one.

Description

United States Patent Kern Sept. 5, 1972 COMMAND FUZE 72 I t t N 1 K S o-ttsdal A Primary Examiner-Benjamin A. Borchelt 1 men or C c e Assistant Examiner-Thomas B. Webb [73] Assignee: Motorola, Inc., Franklin Park, Ill. Attorney-Mueller & Aichele [22] Filed: Feb. 2, 1970 I ABSTRACT [21] Appl. No.: 12,881

US. Cl ..102/70.2 P

The shell includes RF detector circuitry, a pulse counter, and a firing circuit for a detonator which may [52] be caused to explode during flight when it receives a 51 1111.01 ..F42c 13/04, F42c 11/00, F420 15/40 Prsdflermined number of radio Pulses transmitted y 581 Field of Search ..102/70.2 P; 343/7 ground command, or when. after receiving the predetermined number of pulses, the shell also [56] a Cited receives a radio fire pulse by ground command. The fire pulse may be sent out by differential ran ing 3 UNITED STATES PATENTS system which continuously checks the distance to the shell and to the target and sends out the fire pulse 32:23: et when the distance is reduced to the predetermined 3,158,859 11/1964 Resnik ..343/7 3,014,215 12/1961 MacDonald ..102/70.2 P 1 Claim, 6 Drawing Figures BATTERY I 22 r- R F counrsn Flame DETONATOR DETECTOR CIRCUIT CIRCUIT I -----l --l CONSTANT DURATION PATENTEBNP' 5 ma 3588.701

SHEET 2 0F 2 VARIABLY SPACED PULSE PRODUCER A szzzrazzzttt ONLY PULSES AND FIRING 1 RADAR 7 2e PULSE PRoDucER 1 FIG 4 so CONSTANT DURATION VARIABLY SPACED DIFFERENTIAL PuLsEs AND FIRING A RANGE RADAR 1 2s PULSE PRODUCER A ARMING 8| FIRING PULSES TARGET RANGE ARMING PULSES FIRING PULSE IIIIIIIIIIIIIIIIII BATTERY ENERGIZATION TIME \ARIATION IN BATTERY ENERGIZATION TIME FLIGHT TIME INVENTOR. NEW C Kern BY M, 'fw

COMMAND FUZE BACKGROUND This invention relates to a fuze for a shell which will cause the shell to explode under radio control.

In many cases, more damage will be done to a target if a shell explodes at a predetermined distance on the approach side of the target. For example, a shell may pass right over a target and do it no damage; however, if the shell explodes over the target or just before it reaches the target, the target may sustain severe damage. While proximity fuzes are known, a proximity fuze normally cannot distinguish between the background and the target. For example, if the target is behind a wall, the shell including a proximity fuze will be exploded by the proximity to the wall and not by the proximity to the target. Similarly, if the trajectory of the shell to the target is low, the proximity fuze on the shell may cause the shell to explode due to proximity to the ground and not due to proximity to the target. Time fuzes are known for shells, but when time fuzes are used the fuzes on each shell must be set individually and the timing of the fuzes of the successive shells must be corrected in accordance with information noted by observing previous shells. Also round to round ballistic changes cause timingerrors.

It is an object of this invention to provide an improved radio controllable fuze for each shell.

It is an object of thisinvention to provide a fuze which will cause the shell of which it is a part to explode during its flight and after a predetermined time, or at a range which is determined after the shell has been fired out of the gun.

SUMMARY In accordance with this invention, a pulse counter is mounted in the shell and fuze means are provided in the shell to cause the fuze to explode the bursting charge of the shell when the counter has counted a predetermined number of transmitted radio pulses. A radio pulse transmitter is so located as to send pulses to be counted to the shell, the pulses produced by the pulse producer being all equal in length but being spaced in time by a variable amount. By varying the spacing between the pulses, the instant of the time of flight at which the shell explodes may be determined. Since the spacing of the pulses produced by the transmitter is variable while the guns are firing the shells, the effect of the shell explosions may be observed and the pulse spacing may be varied to cause the shell to explode at the most effective point in its flight. As another embodiment of this invention, the first series of pulses may arm the fuze on the shell and then a second distinctive firing pulse may be sent out either by the same transmitter or by a supplemental one. This firing pulse will cause all shells that are in flight and which have been armed to explode but will not cause shells carrying unarmed fuzes to explode. The firing pulse may be transmitted under control of a radio ranging device which measures the distance of the target from the ranging device or which measures the distance between the shell and the target.

DESCRIPTION The invention will be better understood upon reading the following description in connection with the accompanying drawing in which:

FIGS. 1 and 2 indicate in block form two embodiments of this invention, and

FIGS. 3 to 6 are diagrams which are useful in explaining the operation of the device of this invention.

EXPLANATION Turning first to FIG. 1, ashell 10 is illustrated which carries, besides theusual detonator 12, a control or command means for causing firing of thedetonator 12. This means includesanantenna 14 which may be built into the back end of theshell 10 and aradio frequency detector 16, the output of which is coupled to acounting circuit 18. The output of thecounting circuit 18 is fed to afiring circuit 20 whose output is in turn fed to thedetonator 12. Theelements 16, 18 and 20 may be put on a chip such as theintegrated circuit 22. Theelements 12, 16, 18, and 20 are energized by abattery 24.

When theshell 10 of FIG. 1 is fired from a gun in the direction oftarget 26, as shown in FIG. 3, pulses from a constant duration variably spacedpulse producer 28 are radiated by anantenna 30 which is the output of thepulse producer 28 to theantenna 14 on theshell 10. The concussion produced by the propelling charge for theshell 10 causes thebattery 24, which is in an inactive state until the occurrence of the concussion, to become energized. As indicated byline 31 of FIG. 6, a certain length of time must pass before thebattery 24 is energized. Also, as indicated by thelines 32 and 34 of FIG. 6, all batteries do not become energized after exactly the same time interval after the concussion takes place. Therefore, thebattery 24 becomes operative during a time after it has left the gun barrel indicated by thelines 32 or 34 or some time thereinbetween. When thebattery 24 is energized, the describedelectronic elements 16 and 18 become operative to receive, to detect, and to count the pulses 36 (see FIG. 6) transmitted by thetransmitter 28 of FIG. 3. When a predetermined number ofpulses 36, such as 256 thereof, for example, have been counted by thecounter 18, a pulse is applied to thefiring circuit 20 by thecounter 18 to cause thedetonator 12 to explode. The observer can note when theshell 10 has burst and by manipulation of the adjustingwheel 40 of thetransmitter 28, for example, the burst can be brought closer to the gun if it is beyond thetarget 26 by making the time or spaces between thepulses 36 smaller, or further from the gun by making the time or spaces between thepulses 36 greater. Since the shell bursts occur only at the time the counter counts 256 pulses (for example), the time of flight of theshell 10 before it bursts is controllable by making the time between the pulses greater or less. A radio ranging system may be adapted to control the spaces between the pulses in accordance with the distance to the target.

It may be desirable to only arm the shell by means of spaced pulses of uniform width and explode the shell by means of another firing pulse whose time position is adjustable either manually or automatically. Such a shell is shown in FIG. 2. In FIGS. 1 and 2, the same reference characters are applied to similar elements.

In FIG. 2, thechip 42 has applied thereto, besides theRF detector 16, thecounter circuit 18, and thefiring circuit 20, apulse width discriminator 44 and anAND circuit 46. Thecounter 18 and thewidth discriminator 44 are connected between the output of the RF detector l6 and respective input terminals of theAND circuit 46. The output of theAND circuit 46 is connected to the input of thefiring circuit 20.

The operation of the shell of FIG. 2 is explained in conjunction with FIGS. 4 and 5 andline 48 of FIG. 6. Arming pulses 50, which are short and uniform in duration but variably spaced in time, are counted by thecounter 18 of FIG. 2. When it has counted 256 pulses (for example), it applies an output to theAND circuit 46, but at that time theAND circuit 46 has only one input thereto, whereby it has no output. At a desired time, afiring pulse 52 is transmitted to theshell 10. Thisfiring pulse 52 is wider than thearming pulses 36, whereby thefiring pulse 52 gets through the pulse widthdiscriminator circuit 44 which applies the second input pulse to theAND circuit 46. There now being a pulse applied to each of the inputs of theAND circuit 46, theAND circuit 46 applies an output to thefiring circuit 20 which causes thedetonator 12 to explode.

By use of a differentialrange radar apparatus 54, shown in FIG. 5, the firing pulse 52 (FIG. 6) may be sent out automatically when the shell and thetarget 26 are at the right distance apart for inflicting maximum damage on thetarget 26.

Since all thearmed shells 10 that are in the air will be exploded by thefiring pulse 52, even though only the front one is at the desired burst position, it may be desirable to adjust the spacing of thearming pulses 50 so that only theshells 10 that are near thetarget 26 are armed. In this manner,several shells 10 which bracket thetarget 26 may be exploded simultaneously, while theshells 10 that are still at too great a distance on the approach side of thetarget 26, will not be exploded.

Thedifferential range radar 54 of FIG. 5 may be constructed in accordance with the application of Neil C. Kern, Ser. No. 790,327, filed Jan. 9, 1969, entitled Differential Ranging Systems, and assigned to M0- torola, Inc.

What is claimed is: l. A shell including: a detonator, an antenna, a radio detector connected to said antenna, a pulse counter connected to said radio detector and being responsive to an external command signal, a pulse width discriminator, an AND circuit having two input connections and an output connection, and the output of said counter being connected to one input connection of said AND circuit, said pulse width discriminator being connected between the output of said detector and the other input of said AND circuit and the output of said AND circuit being connected to said detonator for causing said detonator to explode in response to said external command.

Claims (1)

1. A shell including: a detonator, an antenna, a radio detector connected to said antenna, a pulse counter connected to said radio detector and being responsive to an external command signal, a pulse width discriminator, an AND circuit having two input connections and an output connection, and the output of said counter being connected to one input connection of said AND circuit, said pulse width discriminator being connected between the output of said detector and the other input of said AND circuit and the output of said AND circuit being connected to said detonator for causing said detonator to explode in response to said external command.

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