US3628458A

US3628458A - Missile destruct initiation assembly

Info

Publication number: US3628458A
Application number: US879070A
Authority: US
Inventors: Emmett J Sands
Original assignee: US Department of Navy
Current assignee: US Department of Navy
Priority date: 1969-11-24
Filing date: 1969-11-24
Publication date: 1971-12-21
Anticipated expiration: 1988-12-21

Abstract

A missile destruct initiation assembly is provided that interconnects a detonator to a high-current source and contains a command destruct circuit for passing a command destruct signal to initiate detonation, and an autodestruct circuit responsive to an autodestruct signal, representative of internal missile malfunction to initiate the detonator. Thus, the assembly for initiating missile destruction performs the dual function of being responsive to a command destruct source or an autodestruct source.

Description

United States Patent lnventor Emmett .l. Sands San Jose, Calif. App]. No. 879,070 Filed Nov. 24, 1969 Patented Dec. 21, 1971 Assignee The United States of America as represented by the Secretary of the Navy MISSILE DESTRUCT lNlTlATlON ASSEMBLY 9 Claims, 1 Drawing Fig.

U.S. Cl 102/70.2 R, 114/21 R Int. Cl F42c 11/00, F42c 15/40, F42c 13/00 Field of Search 102/702 [56] References Cited UNITED STATES PATENTS 3,275,884 9/1966 Segall et a1 102/702 X 3,470,419 9/1969 Sitler et al 102/701 X Primary Examiner-Samuel W. Engle Assistant Examiner-Thomas l-l. Webb A ttorneys-Richard S. Sciascia, Ervin F. Johnston and Thomas G. Keough MISSILE DESTRUCT INITIATION ASSEMBLY STATEMENT OF GOVERNMENT INTEREST The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefore.

BACKGROUND OF THE INVENTION For reasons of safety, missiles are conventionally provided with destruct circuits to inhibit the destruction of the missile during launch, or thereafter, in the event that the missile malfunctions or goes past its intended target, to enable its destruction. Contemporary circuits initiated after a predetermined time, or upon malfunction, are usually separate and distinct from a circuit that is initiated by a remotely originating command signal largely because a timed or autodestruct signal and a remotely originating command signal are usually of vastly different magnitudes and, when handled by the same circuitry, fail to initiate detonation. Providing separate circuits ensures more reliable detonation but results in a duplication of many circuit components. This unnecessary duplication means increased weight and is prohibitive on relatively lightweight airto-air missiles or crew-served antitank missiles. A compact, dual-function destruct initiation assembly remains a desired feature in current, tactical missiles.

SUMMARY OF THE INVENTION The present invention is directed to providing a missile destruct initiation assembly including a potential source connected to a detonator by a gap switch. A command destruct circuit, passing a command destruct signal, is paralleled by an autodestruct circuit, responsive to a signal representative, for example, of a missile acceleration. Both circuits are connected to a destruct trigger circuit that drives the gas-filled gap switch. Substantially, complete reliability is provided in the autodestruct circuit by including a clamping means holding the destruct trigger circuit below the critical magnitude required for initiating the gap switch. Paralleling the autodestruct circuit, an autodestruct inhibit circuit actuates the clamping means to ensure nondestruct operation of the circuit prior to the point in time when the autodestruct circuit passes an arming signal.

Therefore, it is an object of the instant invention to provide a destruct initiation assembly of greater safety.

A further object is to provide an initiation assembly possessing a dual-function capability.

Yet another object is to provide a destruct initiation assembly incapable of initiation of a detonator until a predetermined acceleration is reached.

Yet another object is to provide an assembly responsive to dual-function signals and having common circuitry.

An ultimate object of the instant invention is to provide a missile destruct initiation assembly of high reliability and safety by having a minimal amount of components.

BRIEF DESCRIPTION OF THE DRAWING The FIGURE depicts the schematic diagram of the preferred form of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawing, the missile destruct initiation assembly is depicted as terminating in a common control panel 10, although operatively employed, the assemblys input and output terminals are arranged in a missile housing as convenience and configuration permit. An external source of AC arming potential is connected across terminals 11 and 12 and is coupled to following circuitry when a pair of coils l4 and 15 are energized by an externally originating arm control signal impressed across terminals 16 and 17. In a representative utilization. the arm control signal across terminals 16 and 17 is the signal transferred to the missile when the missile is switched to the off safe" condition prior to launch or after launch during the missile s first motion.

Coils l4 and 15 displace a plurality of relay contacts 18a, 18b, 18c, and 18d to transfer the AC arming voltage to following circuitry. Switches 18a and 18b, connected in parallel for reliability, cooperate to pass AC potential to a source of high DC current 20. The source is formed of a power supply transformer 20a, full-wave rectifier 20b, load resistors 20c, and high-current storage capacitors 20d functioning in an obvious manner to provide a burst of high DC current across a gap switch 22 to a detonator 21. The gap switch is a gas-filled tube, viz a thyratron-type tube, serially joining the current source and the detonator via its cathode and anode. The potential maintained across the gap switch is insufficient to cause conduction by itself, but conduction occurs between the anode and cathode when grid 22a receives a signal that initiates ionization of gas.

When an arm control signal is impressed across terminals 16 and 17, the coils displace the relay contacts and 18b to transfer an ignition arm control signal to terminals 19a and 19b or give a visual representation of the circuits actuation at a remotely located readout.

Aside from providing the high DC circuit, the AC arming potential impressed across terminals 1 l and 12 is fed to an autodestruct circuit 30 via a power supply transformer 31. The autodestruct circuit functions to initiate detonation when some missile malfunction occurs or after a predetermined time has elapsed, indicating that the missile has missed its intended target. However, prior to launch, but subsequent to the missile destruct initiation assemblys receiving the arm control signal, the autodestruct circuit is inhibited by an autodestruct inhibit input at terminal 32. The autodestruct inhibit input is also derived from the AC arming potential through a first power supply transformer secondary 31a terminating in ter minal points 33a and 33b externally feeding the signal to terminal 32. As the AC arming potential activates the destruct initiation assembly and prior to launch, the autodestruct inhibit input is fed from terminal 32 to the base of transistor 43 for clamping certain following elements, the purpose of which will be set out below.

The autodestruct circuit is actuated to permit the generation of an autodestruct signal when a remotely located accelerometer 34 impresses an arm control signal function upon an autodestruct input terminal 30a. The arm control signal function input is produced as a function of missile acceleration. That is to say, as the relative acceleration of the missile reaches a predetermined value representing a safe separation of the missile from the launcher, the arm control signal function is generated in the accelerometer and is passed to the autodestruct circuit to ensure its self-generation of an autodestruct signal. Simultaneously, the accelerometer passes a nullifying signal on lead 34a to autodestruct inhibit input terminal 32 to remove the autodestruct inhibit signal appearing there.

Within the autodestruct circuit, a second power supply transformer secondary 31b derives a biasing potential fed to transistor 35. This biasing potential impressed across transistor 35 is of insufficient magnitude to initiate conduction by itself. However, as the autodestruct arm control signal is fed to the base of the transistor from input terminal 30a, conduction occurs and then an autodestruct signal is generated on an interconnected capacitor 36. The generated autodestruct signal is blocked from a following destruct trigger circuit 50 because transistor 43 maintains a clamp potential of approximately 1 volt at point 44, which potential is held across a second storage means, capacitor 45. The clamping potential is ensured after removal of the autodestruct inhibit input signal to hold transistor 43 in conduction by feeding a positive control signal to the base of the transistor 42 derived from the second power supply transformer secondary 31b.

Spurious signals are prevented from entering and actuating destruct trigger circuit 50 by serially interposing a backbiased, Zener diode 51 that blocks low-magnitude signals from entering the destruct trigger circuit.

The command destruct circuit 46 is provided for passing remotely originating command destruct signals to the destruct trigger circuit when monitoring personnel seek to destroy the missile for purposes of safety or for missile effectiveness. A command destruct signal fed to terminal 47 also is of a magnitude in excess of the back-biasing potential required to break down back-biasing, Zener diode 51 and to initiate conduction through the destruct trigger circuit.

initiation of the destruct trigger circuit hinges on supplying biasing potentials to the anode of either silicon-controlled

rectifiers

52 or 53, and, simultaneously generating, within the destruct trigger circuit, a gating potential sufficient to break down either of the SCR's and cause conduction.

When conduction occurs, a burst of energy is fed to the primary of a trigger circuit coupling transformer 54. The secondary of the transformer is connected to the grid 22a of the gap switch which ionizes the gas to create a conductive path for the high DC current to the detonator.

The electronic coaction and the operation of the above referred to circuit will become more apparent by following the sequence occurring when either a command destruct signal or an autodestruct signal is fed to the gap switch.

Upon supplying the AC arming voltage to the complete destruct initiation assembly via impressing an arm control signal across terminals 16 and 17, power supply transformer 200 provides the high source of DC current while power supply transformer 31 supplies biasing potential to the autodestruct circuit 30, as well as providing an autodestruct inhibit input signal at autodestruct inhibit input terminal 32. The high-current storage capacitors 20d are charged to a magnitude approaching 2,400 volts DC and the entire destruct initiation assembly is now armed, but will not fire the detonator until a command destruct signal or an autodestruct signal is received.

When the command destruct signal is fed to terminal 47, the anode circuit of SCR 53 is energized. The command destruct signal, having passed through Zener diode 51, also provides a signal input to the base of transistor 55. Charging the command destruct signal on capacitors 48 and 48a supplies biasing potential for transistor 55 as well as for a transistor 56. As the command destruct signal is first fed to the transistor 55 base circuit as a step signal, capacitor 57 acts as a short circuit and shunts a resistor 58. Transistor 56 collector current raises the potential across a resistor 59 and provides gate voltages for the SCR's 52 and 53. The collector current also feeds a feedback potential back to the base of transistor 55 via a resistor 60, capacitor 61, and diode 62. As capacitor 57 is charged by the transistor 55 emitter current, transistor 55 emitter voltage is increased. After capacitor 57 charges, approximately 1 volt DC is required at the base of transistor 55 to hold it in the conducting condition. A feedback voltage from transistor 56 clamps transistor 55 into conducting condition momentarily. Transistor 56 is driven into conduction when about 28 volts appear across resistor 59. The energy stored at the anode of SCR 53 is conducted to the primary of trigger circuit coupling transformer 54. The large output pulse having a very fast rise time is produced across the secondary of transformer 54 and is fed to the grid 22a to cause ionization of the gas within gap switch 22. An output pulse of about 2,000 amperes is transferred to the detonator to initiate detonation.

Prior to launch, upon impressing an arm control signal across terminals 16 and 17, the autodestruct circuit is energized through transformer 31 via a first and second power supply transformer secondary 31a and 31b and receives full wave rectified power across the autodestruct inhibit output 330 and 33b, and receives biasing potentials for its transistors 35, 42, and 43. The autodestruct inhibit output appearing across terminals 33a and 33b, full-wave rectified power, is fed to autodestruct inhibit input terminal 32 and to the base of transistor 43 to drive it in conduction and to maintain a lowpotential clamp on capacitor 45.

The rectified output from second power supply transformer secondary 31b, providing biasing potential for transistor 35, also holds transistor 42 in the conducting condition to provide a low-potential clamp on capacitor 45 when the autodestruct inhibit input signal is removed from the base of transistor 43. Thusly biased, transistor 35 is nonconducting and the autodestruct circuit is considered not armed at this point.

A signal originating from accelerometer 34, indicative of the launched missiles having attained a predetermined acceleration, tums on" transistor 35. Transistor 35 collector current charges an autodestruct signal on capacitor 36 through diode 37 and resistor 38. Since the transistors 42 and 43 are both conducting, an accumulated signal on capacitor 45 is still clamped to a low potential by reason of the current flowing through transistors 42 and 43. A supply potential for

transistors

55 and 56 is provided from the charge on capacitor 36 fed through the path including diode 39 and resistor 40. However, no current flows from the

transistors

55 and 56 in the absence of transferring the autodestruct signal stored on capacitor 36 to the base of transistor 55. Thus, the autodestruct circuit is armed with transistors 35, 42, and 43 conducting, and with autodestruct signal of approximately 39 volts DC, for example, charged on capacitor 36.

In the event of missile malfunction, such as a defect in a missiles motor or an improper guidance or firing sequence arises, a circuit interrupter switch 41 interconnected in the collector circuits of transistors 42 and 43 breaks open. The interrupter switch can be a timed break relay or merely consist of a heat-, pressure-, or vibration-responsive break relay strategically located in the missile to interrupt the supply potential of transistors 42 and 43.

With the supply potential holding transistors 42 and 43 in conduction removed via opening of the interrupter switch, the clamp on capacitor 45 is removed. Capacitor 45 is charged with the autodestruct signal stored on capacitor 36 and the anode circuit of SCR 52 is forward biased through lead 520. Simultaneously, the autodestruct signal is fed to the base of transistor 55 via diode 49, Zener diode 51, and resistor 51a to drive

transistors

55 and 56 into conduction according to the same electronic cooperation occurring when the command destruct signal is fed to destruct trigger circuit 50.

The only exception between the operation of the trigger circuit when receiving an autodestruct signal or a command destruct signal, arises from the fact that, upon receiving an autodestruct signal, the gating signal delivered to the gates of both SCR's causes the forward biased SCR 52 to conduct and pass an ionizing pulse to transformer 54, whereas, when a command destruct signal is coupled to the destruct trigger circuit, SCR 53 is forward biased and the gating signal, fed to both gates, actuates only SCR 53 to pass the ionizing pulse to transformer 54.

When the autodestruct circuit initiates detonation of detonator 21, a series of autodestruct signals are passed to the detonator via the trigger circuit, since transistor 35 continues to charge capacitor 36 which, in turn, feeds the charged autodestruct signal to capacitor 45 and onto the destruct trigger circuit. The series of autodestruct signals are desirable to ensure detonation.

Included in the instant assembly are two inhibit functions, an autodestruct safe command function 70 and a destruct acceleration switch inhibit function 71, provided to prevent the charging of capacitor 36, while the missile is on the launch pad, or while traveling the length of the launch tube prior to reaching a magnitude of acceleration required to generate the autodestruct arm control signal in accelerometer 34. Prior to launch, the autodestruct safe command function grounds capacitor 36 through safe/arm relays in an external interlock and the destruct acceleration switch assembly when the acceleration level is below the critical magnitude. As long as either or both of the inhibit functions are actuated, capacitor 36 is grounded through resistors 70a or 710 and the voltage across capacitor 36 remains too low to permit operation of the circuits associated with

transistors

55, 56, SCR 52 and SCR 53.

Terminals are optionally provided for feeding monitoring signals to a visual readout display and, in the preferred embodiment, provide a readout for an autodestruct power indicator at terminal 75 and for an autodestruct power indicator at terminal 76. A return terminal 77 for the command destruct circuit 46 may be provided as well as an autodestruct arm control function return terminal 78 and an autodestruct inhibit input terminal 79 to complete the above described circuits.

Obviously, many modifications and variations of the present invention are possible in the light of the above teachings, and, it is therefore understood that within the scope of the disclosed inventive concept, the invention may be practiced otherwise than as specifically described.

What is claimed is:

1. In a missile destruct initiation assembly including a potential source connected to a detonator by a gap switch, an improvement therefore is provided comprising:

a command destruct circuit configured for passing a command destruct signal; means for producing a signal representative of missile acceleration;

an autodestruct circuit responsive to the acceleration signal including,

means for generating an autodestruct signal as said acceleration signal reaches a predetermined magnitude,

first means coupled to the generating means for storing said autodestruct signal,

second means for storing said autodestruct signal,

clamping means in operative connection with the second storage means for impressing a hold signal, having a lesser magnitude than said autodestruct signal, thereon, and

means coupling the first and second storage means for transferring said autodestruct signal therebetween upon disruption of said operative connection; and

a destruct trigger circuit connecting said command destruct circuit and said second storage means to said gap switch to initiate said detonator upon receiving either one of the destruct signals.

2. An assembly according to claim 1 further including:

interrupter means included in said clamping means for ensuring said disruption of said operative connection upon missile malfunction.

3. An assembly according to claim 2 further including:

inhibiting means connected to said clamping means to ensure said hold signal prior to receiving said acceleration signal at said predetermined magnitude in said autodestruct circuit.

4. An assembly according to claim 3 in which said potential source provides a biasing source to said assembly and a high current source to initiate said detonator upon ionization of said gap switch when receiving either one of said destruct signals.

5. An assembly according to claim 4 further including:

an interlock simultaneously activating said biasing source,

said high-current source, and said inhibiting means upon being actuated to arm said missile prior to launch and, optionally, after launch first motion.

6. An assembly according to claim 1 in which said destruct trigger circuit includes a first SCR interconnected to derive biasing and gate potentials from said command destruct signal and a second SCR interconnected to derive biasing and gate potentials from said autodestruct signal.

7. An assembly according to claim 6 in which said destruct trigger circuit includes means for passing only those said destruct signals above a trigger threshold and to inhibit the deriving of said gate potentials for both SCR's when said destruct signals are below said trigger threshold.

8. An assembly according to claim 7 in which said destruct trigger circuit includes a plurality of interconnected SCRs and transistors for ensuring said gate potentials of the proper magnitude.

9. An assembly according to claim 2 in which said interrupter means initiates a repetitive said autodestruct signal for ensuring conduction in said gap switch and initiation of said detonator.

Claims

1. In a missile destruct initiation assembly including a potential source connected to a detonator by a gap switch, an improvement therefore is provided comprising: a command destruct circuit configured for passing a command destruct signal; means for producing a signal representative of missile acceleration; an autodestruct circuit responsive to the acceleration signal including, means for generating an autodestruct signal as said acceleration signal reaches a predetermined magnitude, first means coupled to the generating means for storing said autodestruct signal, second means for storing said autodestruct signal, clamping means in operative connection with the second storage means for impressing a hold signal, having a lesser magnitude than said autodestruct signal, thereon, and means coupling the first and second storage means for transferring said autodestruct signal therebetween upon disruption of said operative connection; and a destruct trigger circuit connecting said command destruct circuit and said second storage means to said gap switch to initiate said detonator upon receiving either one of the destruct signals.

2. An assembly according to claim 1 further including: interrupter means incluDed in said clamping means for ensuring said disruption of said operative connection upon missile malfunction.

3. An assembly according to claim 2 further including: inhibiting means connected to said clamping means to ensure said hold signal prior to receiving said acceleration signal at said predetermined magnitude in said autodestruct circuit.

5. An assembly according to claim 4 further including: an interlock simultaneously activating said biasing source, said high-current source, and said inhibiting means upon being actuated to arm said missile prior to launch and, optionally, after launch first motion.

7. An assembly according to claim 6 in which said destruct trigger circuit includes means for passing only those said destruct signals above a trigger threshold and to inhibit the deriving of said gate potentials for both SCR''s when said destruct signals are below said trigger threshold.

8. An assembly according to claim 7 in which said destruct trigger circuit includes a plurality of interconnected SCR''s and transistors for ensuring said gate potentials of the proper magnitude.