US3722415A

US3722415A - Electrostatic contact fuze

Info

Publication number: US3722415A
Application number: US00274901A
Authority: US
Inventors: W Lunt
Original assignee: US Department of Navy
Current assignee: US Department of Navy
Priority date: 1963-04-19
Filing date: 1963-04-19
Publication date: 1973-03-27
Anticipated expiration: 1990-03-27

Abstract

1. A contact fuzing system for use in ordnance which will operate at first contact with a target and does not depend upon deformation or deceleration of the weapon carrying the fuzing system for activation comprising: A. A GUIDED MISSILE HAVING FIRST AND SECOND ELECTRICAL CONDUCTING AREAS BEING SEPARATED BY A DIELECTRIC MATERIAL THEREBY FORMING TWO PLATES OF A CAPACITOR, B. AN ELECTRIC POWER SOURCE CONNECTED ACROSS SAID FIRST AND SECOND CONDUCTING AREAS FOR CHARGING SAID AREAS TO A POTENTIAL INVERSELY PROPORTIONAL TO THEIR RESPECTIVE AREAS, C. A LOAD RESISTOR CONNECTED IN SERIES WITH SAID POWER SOURCE AND SAID CONDUCTING AREAS FOR PRODUCING AN OUTPUT SIGNAL VOLTAGE WHEN ONE OF SAID CONDUCTING AREAS IS DISCHARGED BY CONTACTING A TARGET, D. FULL-WAVE RECTIFYING CIRCUIT MEANS CONNECTED ACROSS SAID LOAD RESISTOR FOR PRODUCING A CONSTANT POLARITY OUTPUT SIGNAL WHEN EITHER OF SAID CONDUCTING AREAS IS DISCHARGED.

Description

nited States Patent [191 Lunt [ Mar. 27, 1973 ELECTROSTATIC CONTACT FUZE Wilbur B. Lunt, Arlington, Calif.

[22] Filed: Apr. 19, 1963 [21] Appl. No.: 274,901

[75] Inventor:

FOREIGN PATENTS OR APPLICATIONS 91,592 2/1938 Sweden ..102/70.2 P

Primary Examiner-Benjamin A. Borchelt Assistant Examiner-Thomas H. Webb Attorney-Q. Baxter Warner, J. M. St. Amand and T. M. Phillips EXEMPLARY CLAIM 1. A contact fuzing system for use in ordnance which will operate at first contact with a target and does not depend upon deformation or deceleration of the weapon carrying the fuzing system for activation comprising:

a. a guided missile having first and second electrical conducting areas being separated by a dielectric material thereby forming two plates of a capacitor,

b. an electric power source connected across said first and second conducting areas for charging said areas to a potential inversely proportional to their respective areas,

c. a load resistor connected in series with said power source and said conducting areas for producing an output signal voltage when one of said conducting areas is discharged by contacting a target,

(1. full-wave rectifying circuit means connected across said load resistor for producing a constant polarity output signal when either of said conducting areas is discharged.

1 Claim, 1 Drawing Figure PATENTEDmzmzs WILBUR B. LUNT INVENTOR.

ATTORNEYS ELECTROSTATIC CONTACT FUZE The invention herein described 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 therefor.

The present invention relates to an electrostatic contact fuze and more particularly to a contact fuze which does not depend on the parameters of weapon deceleration or deformation for activation. Contact fuzing has long been the mode of operation of free-fall v ordnance. Present day guided missiles also carry contact fuzing systems to 1) protect the warhead from collision damage when collision courses occur in the blind spots of the ordinary proximity fuzing and (2) to protect against proximity fuze damage when built-in fuzing delays allow collision damage to the fuze prior to actuation. The present invention provides a fuzing system which generates a fuze triggering signal based on the face that a potential difference can be caused to exist between the missile and the intended target. At contact between the missile and target, a flow of electric charges statically carried on the missile will cause a current to flow either to or from the target. The statically carried electric charge is distributed between two conducting areas of the missile insulated from each other and in effect forming two plates of a capacitor. The conducting areas are situated such as to optimize the probability of the one 'or the other contacting the target at the earliest instant of encounter. A power supply such as a battery is used to shiftthe charges in a quantity just sufficient to create a potential difierence between the conducting areas of a magnitude, E. At contact with a conducting target at a differing potential (neutral or uncharged), charges carried on the sensitized conducting area making contact with the target will instantaneously disperse onto the target. This action upsets the previously balanced condition and the battery attempts to recharge the contacting missile area to the, E, potential difference. The resulting flow of recharging current through 'a load resistor creates an output pulse which is used as the firing signal.

Accordingly an object of the present invention is to provide a contact fuzing system which will operate at first contact with a target and does not depend upon deformation or deceleration of the weapon for activation.

Another object of the invention is the provision of an electrostatic fuze which is independent of either closure velocity or missile-target encounter attitudes or angles of approach.

A further object of the invention is to provide an electrostatic fuze which will activate instantaneously at first contact with the target.

Still another object is to provide an electrostatic fuze for use in a guided missile that uses two conducting areas of the missile as electric charge storage areas.

Other objects and many of the attendant advantages of this invention will become readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein there is shown in the single FIGURE, a preferred embodiment of the invention. I

Referring now to the'drawing, there is shown a missile having conducting

areas

12 and 14 insulated guidance radome, nose-section projecting stubs, etc. A

power source such as battery 18 supplies the electric charge to conducting

areas

12 and 14 through switch 20 and load resistor 22. Switch 24 is provided to short circuit the output signal until the missile is armed. A full-wave bridge rectifier 26 is used to provide a constant polarity output regardless of the direction of current flow in load resistor 22. The output from bridge 26 is coupled through coupling capacitor 28 to the firing circuit, not shown.

In operation, and assuming a battery voltage of 500 volts and area 12 is one-fifth the total area of the missile, area 12 would be at plus 400 volts and area 14 at minus volts, with respect to a neutral reference. If under these conditions, area 12 contacted a large neutral conducting target, the charges contained thereon would disperse on the target and its potential would drop to, and remain at, approximately zero volts. Thus, a fuze system imbalance of approximately 400 volts would be immediately created. Power source 18, in order to re-establish an equilibrium condition would have to shift sufficient electrical charge to bring the large area 14 to essentially the full 500 volt battery potential (making the assumption that the target is much larger than area 14). This heavy flow of current through load resistor 22 would produce an output signal sufficient to trigger a firing circuit.

If under the above conditions area 14 had contacted the target, the voltage imbalance would have been only 100 volts and in addition a disproportionately small charge shift would be required to raise area 12 to the 500 volt level due to its lower capacity. Therefore, if

the uncont'acted area is small in comparison to the contacted area, the trigger signal may contain very little energy, requiring that the firing circuit be of very high input impedance.

Switches

20 and 24 are fuze enabling and fuze safety respectively. Switch 20 must be closed prior to switch 24 in the missile flight to allow battery 18 to charge missile 10. Switch 24 retains a short circuit on the fuze output until missile arming occurs.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed is:

1. A contact fuzing system for use in ordnance which will operate at first contact with a target and does not depend upon deformation or deceleration of the weapon carrying the fuzing system for activation comprising:

a. a guided missile having first and second electrical conducting areas being separated by a dielectric 7 material thereby forming two plates of a capacitor,

cl. full-wave rectifying circuit means connected 5 across said load resistor for producing a constant polarity output signal when either of said conducting areas is discharged.