US3886867A

US3886867A - Contact fuze

Info

Publication number: US3886867A
Application number: US573574A
Authority: US
Inventors: Philip Krupen
Original assignee: US Department of Army
Current assignee: US Department of Army
Priority date: 1956-03-23
Filing date: 1956-03-23
Publication date: 1975-06-03
Anticipated expiration: 1992-06-03

Abstract

1. An ordnance device comprising: a first conductive element, an explosive material contained in the first conducting element, an insulating material, a forward conductive element attached by the insulating material to the first element, a detonator means for setting off the explosive material responsive to an electrical current, one side of said detonator means connected to the first element, an electrical lead connecting the other side of said detonator means to the forward conductive element, and means for electrostatically charging the two elements to approximately the same potential; so that when an aforesaid conductive element touches an object with a different electrostatic potential a current flow passing through said detonator means sets off the explosive material.

Description

United States Patent 11 Krupen l l CONTACT FIYZE [75] Inventor; Philip Krupen. Washington. DC.

I73] Assignee: The United States of America as represented by the Secretary of the Army, Washington. DC.

[22] Filed: Mar. 23, 1956 l Appl. No.: 573,574

[52] US. Cl.,- r. [OZ/70.2 R [51] Int. Cl. F42C 11/00 [58I Field of Search 102/702. 70.2 G. 70.2 GL1 310/7; 317/99. 246. 244; 324/109. 60: 250/813 [56! References Cited UNITED STATES PATENTS 1505.042 4/l95l) Gourdon... l(l2/7(l.2 GA

FOREIGN PATENTS OR APPLICATIONS 673.794 6/l952 United Kingdom 3l0/7 June 3, 1975 Primary ExaminerRohert F. Stahl Assistant E.t'aminerC. T. Jordan Attorney, Agent. or Firm-Nathan Edelberg: Robert P. Gibson; Saul Elbaum EXEMPLARY CLAIM I. An ordnance device comprising: a first conductive element, an explosive material contained in the first conducting element, an insulating material, a forward conductive element attached by the insulating material to the first element. a detonator means for setting off the explosive material responsive to an electrical current, one side of said detonator means connected to the first element, an electrical lead connecting the other side of said detonator means to the forward conductive element. and means for electrostatically charging the two elements to approximately the same potential; so that when an aforesaid conductive element touches an object with a different electrostatic potential a current flow passing through said detonator means sets off the explosive material.

5 Claims, 5 Drawing Figures DETONATOR INSULATION .1 INVENTOR it Phil/)0 Krup en ATTORNEYJ.

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

This invention relates to fuzes for ordnance projectiles and more particularly to electrostatic contact fuzes.

In certain projectiles, such as those containing shaped charges, it is necessary that the explosive charge within them be detonated immediately upon contact with the target. This invention provides an electrostatic fuze adapted to detonate the explosive charge the instant contact is made. It comprises a projectile with two conducting parts divided by an insulator. Both parts are given an electrical charge after launching, then when one part touches the target, that part discharges to the target and an electrical potential exists between the two parts. The current flow resulting from this potential is utilized to initiate the explosive charge.

An object of this invention is to provide a fuze for ordnance projectiles which initiates detonation the instant contact is made with a target.

Another object is to provide a fuze which has a high degree of safety.

Another object of this invention is to provide a means for producing an electrostatic charge for such a fuze.

Still further objects are to achieve the above with a device that is sturdy, simple, and reliable, yet cheap and easy to manufacture.

The specific nature of the invention as well as other objects, uses and advantages thereof will clearly appear from the following description and from the accompanying drawing, in which:

FIG. 1 is a schematic representation of a projectile in accordance with this invention approaching a target.

FIG. 2 is similar to FIG. 1 at the instant of contact.

FIG. 3 is a half sectional view of a device in accordance with this invention, with some electrical components shown schematically.

FIG. 4 is an elevational view of another means of charging a projectile, partially broken away.

FIG. 5 is a schematic representation of the device shown in FIG. 4.

As seen in FIGS. 1 and 2 a projectile containing an explosive material 12 in the form of a shaped charge has forward electrically conductive element or segment 14 separated from the projectile body and first conductive element or casing 16 by electrical insulating material 18. The casing 16 and segment 14 are electrically charged (shown positive in FIGS. I and 2) by means described later. The segment 14 is connected by lead 20 to detonator 22 in the back of the projectile to set off the explosive material 12 as required for shaped charge operation. When the segment 14 makes contact with target 24 (FIG. 2), which has a different electrical potential from the projectile, the charge on segment 14 drains to the target and an electrical potential is developed across detonator 22. The resulting current flow causes immediate detonation. If casing 16 first contacts an object, its charge will drain and a potential will likewise be developed across detonator 22.

It is necessary that a low-energy detonator 22 be used. Well-known carbon-bridge and conductive-mix types are suitable.

Four methods of electrostatically charging the projectile are: contact fingers, dust-filled cartridge, windblown dust (FIG. 3), and capacitance (FIGS. 4 and 5).

Contact fingers at the muzzle ofa gun are well known to the art. The potential required on the fingers for this type charging is of the order of 10,000 volts. As the energy is low, this potential may be obtained from small battery and vibrator units that are well known in the electrical art.

A system for charging a projectile by releasing dust from a cartridge containing dust and gas under pressure is fully disclosed in a co-pending application by Theodore et al., Ser. No. 458.999 filed Sept. 28, I954, under common assignment to the Government as represented by the Secretary of the Army.

FIG. 3 shows a system for charging by wind-blown dust. In this system a nose piece 26 is attached to casing 16 by threads 28. The nose piece comprises an annular metal base 30 to which is attached, by molding for example, tip 32 of insulating material. The majority of tip 32 is covered by the forward conducting segment 14. At the portion of tip 32 adjacent to the base 30 is an annular protuberance 34 having a series of shallow depressions or cavities 36 along its outer surface. Band 38 is threaded to base 30 and covers protuberance 34 and cavities 36. Narrow slots 40 in band 38 are over each cavity 36. The cavities 36 are filled with dust 42, such as talc, before firing or launching. The air rushing along the projectile blows the dust out of the slots 40 charging the projectile by the triboelectric effect. The force of the air is increased because the forward portion of the cavities act as a scoop, and the slots are at a point of reduced pressure resulting from the Bernoulli effect.

Insulated lead 20 connects to segment 14 through a hole 44 in tip 32. The other end of lead 20 connects to switch 46 in the safety and arming mechanism. This switch insures that segment 14 and casing 16 are at the same potential by grounding the lead 20 to the casing during storage, firing and charging (position shown in FIG. 3). The switch also shorts the detonator. The switch is activated by an ordinary time delay mechanism initiated by setback so that its connects lead 20 to detonator 22 after charging. It will be noted that segment 14 is as widely separated from casing 16 as practicable to reduce capacitance between the two.

The system is very safe because in addition to the regular safety and arming mechanism the only source of power is the dust 42 in the cavity 36. The only way an electrical charge is produced is by the high velocity air resulting from the flight of the projectile.

The electrostatic charging system shown in FIG. 4 is styled capacitance charging because of its analogy to the capacitor in the schematic representation of FIG. 5. In it a bomb 50 has an explosive charge 52, a forward conducting segment 54 separated from the conductive casing 56 by insulating material 58. The contemplated detonator circuit is the same as disclosed above. The bomb 50 is connected to aircraft 60 by conventional shackles 62. The casing 56 has a can 64 inserted in it, electrically connected to it. Plug 68 is snugly fitted in the can 64 but insulated from it by dielectric material 66 between the plug and can, thereby forming a capacitor 69. The plug 68 is attached to aircraft 60 by an electrical cable 70 which is electrically connected to one side of direct current power supply 72 within the aircraft. The other side of power supply 72 is connected to the aircraft and through shackles 62 to bomb 50 and can 64. In operation, the shackles 62 are opened and the bomb 50 is separated from the aircraft and one side of power supply 72. The charge which is on the can half of capacitor 69 is therefore trapped on it, As the bomb falls, the cable 70 pulls plug 68 away from can 64 and the charge on the can is distributed through the bomb. The important factor is to obtain enough charge on the bomb to operate the detonator. Because of the high capacitance between plug 68 and can 64, a power supply potential of about 100 volts is sufficient.

It will be apparent that the embodiments shown are only exemplary and that various modifications can be made in construction, materials, and arrangement within the scope of the invention as defined in the appended claims For example, the original signal can be amplified before applying it to a less sensitive detonator.

I claim:

2. The invention as defined in claim 1 wherein said means for electrostatically charging the two elements comprises: a can inserted in and electrically connected to said first element; a plug snugly fitted in the can; a dielectric material; the plug insulated from the can by the dielectric material; and a direct current power supply one side ofwhich is connected to the plug and other side connected to said first element.

3. The invention as defined in claim 1 wherein said means for electrostatically charging the device as a whole comprises: an annular protuberance on said insulating material. the surface of said protuberance having cavities; dust in the cavities; and a slotted band covering the protuberance and cavities, said slotted band electrically connected to said first element.

4. In an ordnance projectile, means for electrostatically charging the projectile comprising: the outer surface of the projectile having a cavity, dust in the cavity, and a band covering the cavity, the band having a slot over the cavity so that as air rushes over the projectile it blows dust from the cavity.

5. In an ordnance projectile, means for electrostatically charging the projectile comprising: a can inserted in the projectile. a plug removably mounted in the can, dielectric material between the plug and the can, a direct current power source one side of which is connected to the plug, and means for connecting and disconnecting the other side of the power source to the can.

Claims

2. The invention as defined in claim 1 wherein said means for electrostatically charging the two elements comprises: a can inserted in and electrically connected to said first element; a plug snugly fitted in the can; a dielectric material; the plug insulated from the can by the dielectric material; and a direct current power supply one side of which is connected to the plug and other side connected to said first element.

3. The invention as defined in claim 1 wherein said means for electrostatically charging the device as a whole comprises: an annular protuberance on said insulating material, the surface of said protuberance having cavities; dust in the cavities; and a slotted band covering the protuberance and cavities, said slotted band electrically connected to said first element.