US3353486A

US3353486A - Self-destructing fuze system for rotating projectiles

Info

Publication number: US3353486A
Application number: US533377A
Authority: US
Inventors: Robert M Haiken
Original assignee: Individual
Current assignee: Individual
Priority date: 1966-03-03
Filing date: 1966-03-03
Publication date: 1967-11-21
Anticipated expiration: 1984-11-21

Description

R. M. HAIKEN 3,353,486

SELF-DESTRUCTING FUZE SYSTEM FOR ROTATING PROJECTILES Nov. 21, 1967 Filed March 5, 1966 lllllh United States Patent the Army Filed Mar. 3, 1966, Ser. No. 533,377 3 Claims. (Cl. Mil-70.2)

ABSTRACT 0F THE DISCLOSURE An auxiliary fuze system for destroying an explosive projectile after a time delay. An unbalanced rotor element is mounted coaxially with the projectile on the spin axis to drive a mechanical timing gear train or to provide a magnetic field to generate a current in generator windings associated therewith in response to rotation of the projectile in flight. An auxiliary fuze train for exploding the main charge of the projectile is initiated by current from the generator windings through switch means provided by a series capacitor in circuit therewith. The capacitor is arranged to break down after a delay time during which it charges to the break-down point, or to charge over a similar delay time and fire a bypass transistor switch means for applying the generator current to fire the auxiliary fuze train. The gear train operates to effect a delayed mechanical switch closing for the same purpose. Any firing-current or power source may be used in this case.

The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment to me of any royalty thereon.

The present invention relates to rotating fuzed projectiles of the type that detonate on impact with a target such as an enemy aircraft, and more particularly to a system for detonating the charge of the projectile if the main fuze fails to impact upon a target.

Frequently, when firing against enemy aircraft flying over friendly territory, the projectile may fail to impact its target. If allowed to continue its flight, the projectile may impact and damage ground installations or personnel, or become a hazard if it falls and fails to detonate. The system of the present invention of the self-destructing type will detonate such a projectile after it has passed its target and before it impacts the ground.

This need for self-destructing fuze means has existed for as long as high explosive projectiles have been used as a defense against aircraft. The problem has been solved in the past by various mechanical time devices, mechanical spin sensors, or pyrotechnic time self-destructing devices.

It is an object of this invention, therefore, to provide an improved self-destructing system for projectiles having means whereby, if the main fuze fails to detonate, an auxiliary fuze will do so and destroy the projectile after it has passed its objective. Over friendly territory thus if the projectile misses its target, the auxiliary fuze explodes the projectile before it can fall on anyone therein.

It is a further object of this invention to provide an improved self-destructing fuze system for rotating fuzed projectiles which includes a series of operative elements adapted for electrical or mechanical operation with substantially equal effectiveness.

It is also a further object of this invention to provide an improved self-destructing fuze system for rotating projectiles which is responsive to rotation of the projectile in operation and includes an inertial power unit operating on the spin axis of the projectile to produce the timing operation and auxiliary fuzing of the projectile.

3,353,486 Patented Nov. 21, 1967 In accordance with the invention, a basic component is an unbalanced rotor whose axis of rotation is located on the center line of the projectile, which is also the axis of spin, but Whose center of mass is remote from the axis of rotation. The unbalanced rotor is then utilized to provide energy storage, either electrical or mechanical, and further conversion to chemical action or detonation, to fire the main charge independently of any fuze train and firing means provided for the projectile on impact. Because of the separation of the center of mass and the axis of spin, the rotor element tends to remain stationary relative to the earth and the projectile spins in its ballistic flight about the stationary rotor element. Thus, the rotor relies upon inertia and gravity forces for its operation. The rotor corresponds to the power unit and is connected to suitable integrator and convertor means which initiates the destruction of the projectile through a fuze train, if required, and the projectile main charge. The critical total power output is dependent upon projectile spin rate and distance or time of flght to the desired destruction point, and is affected by the inherent drag in the power unit.

The invention will further be understood from the following description, when considered with reference to the accompanying drawing, and its scope is pointed out in the appended claims.

In the drawing,

FIG. 1 is a schematic block diagram of a self-destructing fuze system for a rotating projectile showing the main elements thereof and their operative relation in accordance with the invention,

FIG. 2 is a side view in elevation of a typical power unit of the electrical type for the system of FIG. 1, partly in section and partly broken away, to show the interior elements thereof, together with circuit connections therefor, in accordance with the invention,

FIG. 2A is a schematic circuit diagram of a modification of a portion of the circuit of FIG. 2 in accordance with the invention,

FIG. 3 is a cross-sectional view of the entire unit of FIG. 2 taken on the section line 3-3 to show further details thereof in accordance with the invention, and

FIG. 4 is a schematic diagram of the system of FIG. 1 adapted for mechanical operation and showing a typical arrangement for the entire unit integrating means and conversion means of the system of FIG. 1, in accordance with the invention.

Referrin to the drawing, wherein like elements are designated by like reference characters throughout, and referring particularly to FIG. 1, a rotating projectile, indicated in dash and dot lines at 5, includes in the present example, a piezoelectric generator or transducer 6 at the forward end for generating a voltage upon impact. This element is often referred to as a lucky. This generated .voltage is applied to fire a fuze train 7 as indicated by the arrowed line 8, and this in turn fires the main charge 10 of the projectile as indicated by the arrowed line 9.

The main fuze system of the projectile in the present example thus includes the piezoelectric generator or lucky 6, the fuze train 7 and the connecting lines 8 and 9 for the main charge 10. In accordance with the invention, an auxiliary fuze system is also connected with the main charge to effect independent firing thereof should the projectile fail to impact a target within the desired range.

The auxiliary fuze system, placed to the rear of the main charge in the present example, includes energy sup ply means such as the power unit 12 which operates upon rotation of the projectile, integrator means 14 which operates to accumulate the energy output of the power unit 12 through connection therewith as indicated at 13, energy conversion means such as a converting unit or element 16 which converts the accumulated energy from the inte grator 14, through connection therewith as indicated at 15, for firing the fuze train 18 through an output connection 17 and this in turn fires the main charge through the connection 19.

In operation the integrator means 14 accumulates the energy output of the power unit 12 and when a given total output has been achieved, as over a given number of revolutions of the projectile, it accumulates a sufficient quantity of energy to trigger the converter means 16 and so fire the charge through the fuze train. This is after the lucky or main firing element 6 and its main fuze train 7 have failed to operate by reason of missing the target. The critical total power output is dependent upon the projectile spin rate and the time of flight through the distance to the desired destruction point which is beyond the estimated distance from the target. This disance to the destruction point is thus measured in number of revolutions of the projectile which can be determined. The energy accumulated by the integrator for applying to the converter is designed to be a maximum to insure operation at a point beyond the proper firing point for the projectile.

This system as shown in FIG. 1 is adapted to operate either by the principle of operation outlined, through electrical connection means, or through mechanical means as may be desired or best suited to the requirements of a given projectile or application. If it is desired to utilize the principle of operation, as described, in an electrical configuration, the power unit 12 is a generator which operates to produce output current or energy upon rotation of the projectile in flight after firing. One arrangement of such a generator in accordance with the invention utilizing the unbalanced rotor as above referred to, is shown in FIGS. 2 and 3 to which attention is now directed along with FIG. 1.

The power unit or generator 12 of the present example is provided with an outer elongated cylindrical casing 22, preferably of plastic or light insulating material, on which are placed a number of longitudinally-extending generating windings, such as two in the present example, as shown at 23 and 24. These are connected in series aiding relation to each other and have respective terminal ends or leads 25 and 26. The lead 25 is connected directly with the integrator 14 as indicated at 13 while the lead 26 is connected therewith, as indicated at 13, through a control switch 28 and a connecting lead 29.

The

windings

23 and 24 are excited in operation by a rotor 30 of an elongated flat bar type having north and south poles 31 and 32 along opposite edges as indicated in FIGS. 2 and 3. The rotor is provided with a longitudinally-extending shaft 33 which is off-center with respect to the body of the rotor and extends along one edge thereof, presently near the north pole of the magnet. The shaft 33 is mounted in suitable end hearings in the casing 22, one of which is indicated at 34. The axis of this shaft extends along the spin axis of the projectile and the center of the casing 22, or in other words the unbalanced weight or rotor 30 has its axis of rotation located on the center line of the projectile which is also the axis of spin, while its center of mass, indicated at 35 in FIG. 3, is remote from the axis of rotation.

Because of the separation of the center of mass and the axis of spin, the rotor element 30 tends to remain stationary relative to the earth while the projectile 5 and the remainder of the elements about it spins in ballistic flight. This causes the rotor pole to be passed by the

rotating coils

23 and 24 to effect a generation of voltage therein and, since they are connected in series aiding relation, the voltage output of both coils is added and derived at the

terminals

25 and 26. Presently the switch 28 is of the inertia type which closes only when a very high acceleration is attained, as when the projectile is launched into its initial flight.

An electrical storage capacitor 37 in the integrator 14 is connected with the

leads

25 and 29 through the terminals 13, as indicated, and thence through a series connection with the converter 16 at the terminals or connection elements 15 and through an internal fuze element 39 therein of the series resistance type. The latter is associated with an electrical detonator 40 which, in turn, is connected through the fuze train 18, at its input and

output connections

17 and 19, with the main charge 10 to which is also connected the main fuze train connection 9 as described hereinbefore.

The capacitor 37 of the integrator means 14 is adapted to store an excessive charge suflicient to close a normallyopen transistorized by-pass element 38 connected in parallel relation thereto. Current from the generator is then applied directly through the by-pass 38 to the electrical fuze element 39 which, in turn, then ignites or fires the electrical detonator 40. When this detonates the ignition is then passed on through the fuZe train 18 to the main charge 10 and fires the latter, thereby destroying the projectile shortly after it passes its objective, as provided by the rotation of the projectile to that point.

In FIG. 2A a capacitor 37A is provided in series with the fuze element 39 as a modification of the circuit. This is a low-capacity capacitor which breaks down and discharges when the appropriate charge level is reached. Thus in itself it provides a switch for closing the circuit with the fuze element 39 and provides a direct connection therewith to the

generator windings

23 and 24. This effects the same discharge of the detonator 40 and the main charge it as in the previous example. Both circuits utitize the electric detonator means 39-40 as the converter. In one circuit, the generator output from the

windings

23 and 24 charges the capacitor 37 of higher capacity than the critical charge so that when the critical charge is attained, the transistorized element 38 of the circuit shorts the capacitor 37. The energy stored in the capacitor initiates the electrical detonator 39-40 which transmits the detonation to other elements of the fuze train 18 and on to the main charge it). In the modified circuit of FIG. 2A, the capacitor 37A is of such low capacity that it breaks down when the critical charge is attained. and causes initiation of the electric detonator 39-40 as before.

If it is desired to utilize the principle of operation described, in a mechanical configuration, the system of FIG. 4 may be used, which is now referred to along with the preceding figures. in this mechanical configuration the power unit 12A is substantially the same as the electrical power unit of FIG. 2 without the windings and Without magnetizing the rotor 30A. The rotor 30A operates as an unbalanced weight whose axis of rotation is located on the center line of the projectile as before and this axis is also the axis of spin while the center of mass of the rotor is remote from its axis of rotation. The rotor element 30A thus tends to stand still in flight while the remainder of the projectile rotates about it.

In this case the shaft 33 is connected to a mechanical integrator means 14A which is a gear train 45 having an input gear 46 on the power-unit shaft 33 and about which the gear train rotates to drive an output shaft 47 in connection with a converter 16A which is an indexed detonator having an operating disk or rotating element 48 and a trip mechanism 4-9 associated therewith for triggering the detonator 40A after the converter has rotated a certain number of times in flight to bring the operating elements of the two devices 48 and 49 together at a predetermined time in the flight which is after the time when the projectile should have reached its target.

Thus in the present example, the shaft 33 of the powerunit is fixed to the input gear 46 and drives the integrator 14A which is the gear train of suitable design. The gear train drives the converter 16A which includes a timing mechanism that, at the proper time, utilizes the mechanical output of the gear train to initiate the detonating device 40A and hence set off the fuze train 18, as before,. for the main charge 1Q,

The operating sequence for the self-destructing fuze system in the electrical configuration shown in FIGS. 2 and 3 may briefly be described to further indicate the manner of operation of the system. Knowing the range or time of the flight at which it is desired to destroy the projectile and the total number of revolutions the projectile may have attained when it reaches that point, the fuze components are designed to match for this timing. Upon the launch of the projectile 5 a set-back mechanism, hereinbefore referred to and indicated at 50 in FIG. 2 retracts, thereby leaving the magnetized rotor 30 free to tend to remain stationary in rotation with respect to the earth while the

windings

23 and 24 spin around it, thus generating electrical energy which is a fixed output for each revolution of the projectile. At the time the set-back device 50 operates, the inertia switch 28 closes thus allowing the remainder of the circuit to energize. The output of the generator or power unit 12 charges the capacitor 37 and when the charge reaches the required level, the capacitor 37 is dischargd as the switch is closed and the electric detonator 3940 is initiated. The detonator then initiates the remainder of the fuze train 18 which, in turn, initiates the main charge and destroys the projectile.

Thus in accordance with the invention a rotating fuzed projectile is provided with an auxiliary fuze device or system so that if the main fuze fails to detonate by reason of impact, the relative rotation between an unbalanced armature element and other electrical or mechanical elements of the auxiliary fuze carried by the projectile causes suiiicient energy to be generated to detonate the auxiliary fuze. Thus if the projectile misses its target, the auxiliary fuze system will explode the projectile before it can fall on friendly territory.

I claim:

1. In a rotating fuzed projectile having a main detonating charge and a main fuze train operative to fire said charge on impact, an auxiliary self-destructing fuze system therefor comprising, means providing a supply of energy operative upon rotation of said projectile in flight, integrator means connected to said energy supply means for accumulating the energy output therefrom over a predetermined time of flight as measured by the number of revolutions of said projectile, converter means connected with said integrator means for operation in response to energy storage by said integrator means reaching a predetermined level, a second fuze train connected with said converter means and responsive to operation thereof providing a detonation-propagating connection between said convertor and said main charge for eifecting detonation thereof independently of said main fuze train of said projectile, said energy supply means including an unbalanced rotor element the axis of rotation of which is adapted to be located on the center line of the projectile which is the axis of spin thereof and whose center of mass is remote from the axis of rotation, and the integrator and converter means being connected in series relation in the order named with said energy supply means and responsive to rotation of the projectile about said unbalanced rotor to apply a regulated and converted energy output therefrom to said main charge as an auxiliary fuze line.

2. A self-destructing fuze system for a rotating fuzed projectile having a main detonating charge and a main fuze train therefor normally operated from impact, comprising in combination, an unbalanced rotor element having an axis of rotation adapted to lie along the center line of the projectile and on the spin axis thereof and having a center of mass remote from said axis of rotation, means for deriving and storing output energy from the rotational spin of said projectile about said axis of rotation of the rotor element, means connected with said rotor element for storing said energy output over a predetermined rotational limit representative of a desired distance of travel of said projectile, a second fuze train for said main charge, and means for converting and applying said stored energy to effect detonation of said main charge through said second fuze train independently of the main fuze of said projectile, said rotor element being magnetized and provided with electric generator windings associated therewith to generate electric current upon rotation of said projectile, and the storage means including a capacitor and a detonator element connected serially in circuit with said generator windings for receiving its charge therefrom, and said capacitor being subject to by-pass in response to energy storage thereby to a predetermined level.

3. A self-destructing fuze system for rotating projectiles and the like having a main detonating charge and a fuze train operative to fire said charge on impact, comprising in combination, a power unit operative on rotation with and on the axis of a projectile to generate a charge-firing current, a storage capacitor and an electric detonator for said main charge connected serially in circuit with said power unit, a transistor connected with said capacitor to fire in response to a predetermined charge carried by said capacitor and effect current discharge from said power unit through said detonator for firing the main charge, said power unit including a magnetic rotor element and generator output windings rotatable with the projectile about said rotor element, and said rotor element being mounted with its axis of rotation on the spin axis of the projectile but with its center of mass offset from said spin axis in operation.

References Cited UNITED STATES PATENTS 1,755,023 4/1930 Ruehlemann 10270.2 2,825,283 4/1958 Sobelman 10270.2 2,856,820 10/1958 Schmued et al. 102-79 X 2,891,479 6/1959 Alexander et al. 102-70.2 2,978,983 4/ 1961 Okstein et al. 102-79 2,981,890 4/ 1961 Ruehlemann 102--70.2 X 2,991,716 7/1961 Israel et al. 102--70.2 3,008,416 11/1961 Ruehlemann 102-70.2 3,088,409 5/ 1963 Yavelberg 102-70.2 3,241,373 3/1966 Ricketts et al.

BENJAMIN A. BORCHELT, Primary Examiner.

W. C. ROCH, T. H. WEBB, Assistant Examiner.

Claims

1. IN A ROTATING FUZED PROJECTILE HAVING A MAIN DETONATING CHARGE AND A MAIN FUZE TRAIN OPERATIVE TO FIRE SAID CHARGE ON IMPACT, AN AUXILIARY SELF-DESTRUCTING FUZE SYSTEM THEREFOR COMPRISING, MEANS PROVIDING A SUPPLY OF ENERGY OPERATIVE UPON ROTATION OF SAID PROJECTILE IN FLIGHT, INTEGRATOR MEANS CONNECTED TO SAID ENERGY SUPPLY MEANS FOR ACCUMULATING THE ENERGY OUTPUT THEREFROM OVER A PREDETERMINED TIME OF FLIGHT AS MEASURED BY THE NUMBER OF REVOLUTIONS OF SAID PROJECTILE, CONVERTER MEANS CONNECTED WITH SAID INTEGRATOR MEANS FOR OPERATION IN RESPONSE TO ENERGY STORAGE BY SAID INTEGRATOR MEANS REACHING A PREDETERMINED LEVEL, A SECOND FUZE TRAIN CONNECTED WITH SAID CONVERTER MEANS AND RESPONSIVE TO OPERATION THEREOF PROVIDING A DETONATION-PROPAGATING CONNECTION BETWEEN SAID CONVERTOR AND SAID MAIN CHARGE FOR EFFECTING DETONATION THEREOF INDEPENDENTLY OF SAID MAIN FUZE TRAIN OF SAID PROJECTILE, SAID ENERGY SUPPLY MEANS INCLUDING AN UNBALANCED ROTOR ELEMENT THE AXIS OF ROTATION OF WHICH IS ADAPTED TO BE LOCATED ON THE CENTER LINE OF THE PROJECTILE WHICH IS THE AXIS OF SPIN THEREOF AND WHOSE CENTER FO MASS IS REMOTE FROM THE AXIS OF ROTATION, AND THE INTEGRATOR AND CONVERTER MEANS BEING CONNECTED IN SERIES RELATION IN THE ORDER NAMED WITH SAID ENERGY SUPPLY MEANS AND RESPONSIVE TO ROTATION OF THE PROJECTILE ABOUT SAID UNBALANCED ROTOR TO APPLY A REGULATED AND CONVERTED ENERGY OUTPUT THEREFROM TO SAID MAIN CHARGE AS AN AUXILIARY FUZE LINE.