US2892407A

US2892407A - Shaped cavity explosive charge

Info

Publication number: US2892407A
Application number: US268651A
Authority: US
Inventors: Norman A Macleod
Original assignee: Individual
Current assignee: Individual
Priority date: 1952-01-28
Filing date: 1952-01-28
Publication date: 1959-06-30
Anticipated expiration: 1976-06-30

Description

June 30, 1959 N. A. MacLEOD SHAPED CAVITY EXPLOSIVE! CHARGE INVENTOR. NgRMAN A.MAcLEOD. B 9!? 1 ATTORNEY nited States T 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 therefor.

This invention relates to explosive charges of the metal lined shaped cavity type, and more particularly to a charge of the type indicated wherein the gases and stream of metal particles produced by the explosion form a jet having maximum velocity and other desired characteristics.

, A shaped charge usually comprises a cylinder of high explosive with the forward end formed with a metal lined conical cavity and the rear end provided with an axially positioned detonator which, upon being actuated, creates a detonation wave traveling forwardly in the high explosive to the cavity, which thereupon produces a high velocity jet of gases characteristic of this type of charge. The detonation wave in such case first envelops the apex, and thence moves forwardly to the base, of the cone.

The present invention contemplates initiating the explosion of the high explosive in a transverse plane disposed forwardly of the rear end of the charge, and so disposed with reference to the cone that the detonation wave, instead of traveling from the apex to the base of the cavity, will travel from the base to the apex thereof, or will be caused to move otherwise in such relation to the cavity as to produce the desired characteristics in the jet. Accomplishment of this result may involve the use of a shield surrounding the rear end of the charge and separating the charge from the detonator, the two being connected only by a layer of explosive material overlying the shield. Actuation of the detonator thereby initiates the explosion in the shaped charge simultaneously at all points along the edge of the shield.

An object of the invention is to control the explosion characteristics of a shaped charge by a simultaneous line or peripheral initiation of. the charge to produce sym metrical or asymmetrical detonation wave fronts with respect to the axis of the charge.

A further object of the invention is to control the direction, velocity, and initiation characteristics of the jet from a shaped cavity charge.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following description.

Fig. 1 is a view in longitudinal cross-section of a device embodying the invention;

Fig. 2 is an enlarged fragmentary view showing a modified form of shield;

Fig. 3 is a view similar to Fig. 2, but showing a modified form of the invention;

Fig. 4 is a similar view of a projectile embodying a further modified form of the invention; and

Fig. 5 is a similar view of a further modified form of the invention.

The form of the invention shown in Fig. 1 includes a charge of high explosive having its forward end atent Patented June 30, 1959 shaped with a cavity in conical or other suitable form, and provided with a metal liner 12. Since the forms which the cavity of a shaped charge may take are known, it is convenient to refer herein to the cavity as a cone, having an apex and a base, even though the actual shape of the cavity may depart considerably from the conical. Surrounding the charge 10 is a shield 14 which may be of steel or other rigid material of sufficient thickness to prevent the transmission of a detonation wave therethrough. The shield 14 terminates near the base of the metal liner 12 to provide an annular gap or opening 16. A relatively thin outer shell 18 encloses the assembly, and is spaced from the shield 14 to provide a cylindrical space in which is placed a thin layer of explosive 20, which may or may not be of the same composition as that of charge 10. A detonator 22 is mounted in the shell 18 at the rear end or base of the device, and is actuated in any suitable manner to set oif the explosive 20. The Wave front thus caused travels forwardly through explosive 20, and thence passes through opening 16 to initiate the explosion of charge 10 at the base of the cone indicated at 12.

Successive positions of the wave front are indicated by broken lines A, which show the wave front progressing rearwardly from opening 16 to the apex of the cone. Simultaneously, the liner 12 will be collapsed inwardly along the lines indicated at L, M, and N, the latter position being the instantaneous position of a rapidly collapsing cone at a time when a considerable portion of the high explosive charge is as yet undetonated. The pressure within the cone is therefore sustained during its collapse, producing very high forward velocity of the jet when the lines N meet. The cone is thus collapsed by a progressive decrease in its radius. Stated differently, the walls of the instantaneous cone indicated at N approach each other at higher velocity than would be the case in the conventional shaped charge, wherein the wave front travels forwardly from the detonator, reaching the apex of the cone first and collapsing the cone by decreasing the altitude; in such a case, the jet begins to form only after a considerable portion of the high explosive has been detonated, and formation of the jet continues for a short time after the high explosive has been completely detonated, whereas with the arrangement shown in Fig. 1, formation of the jet begins with the beginning of detonation, and is completed at about the same instant as detonation is completed, with resulting higher jet velocity. In Fig. 2 is shown a modified form of shield, comprising two spaced

sheets

24, 25 of steel or the like with an interposedlayer 26 of litharge. The composite shield thus formed may be substituted for the shield 14 of Fig. 1. The form of the invention shown in Fig. 3 is designed to initiate explosion of the high explosive at apoint opposite'to the walls of the cone, thus producing a jet of somewhat different characteristics than is produced by the device of Fig. 1. In the Fig. 3 device, the elements are the same, and are designated by the same reference numerals, as in Fig. 1, except that the shield, indicated at 30, terminates well to the rear of the base of the conical liner 12, with the result that the explosion propagated in the thin layer of explosive 20 is transmitted to the high explosive 10 at a point (more accurately, at all points of a circle) lying opposite to an intermediate portion of the walls of liner 12. The direction of travel of the wave front is therefore substantially normal to said walls, and the cone is collapsed by simultaneous decrease of its radius and altitude. The jet produced by such collapse will differ not only from that produced by known types of shaped charges, but also from that produced by the form of the invention shown in Fig. 1. Various modified efiects can be obtained by varying the length of the shield 30 and the shape and size of the cavity.

The projectile illustrated in Fig. 4 comprises an outer shell 32 provided with an ogive 3'4 and containing a charge of high explosive formed with a shaped cavity provided with a liner 1 2 similar to that of Fig. 1. At the tip of the ogive is an impact fuse 36. The inner surface of the ogive is coated with a thin sheet of explosive 38 which transmits the explosive wave from the' fuse 36, along the sheet 38, through an annular opening 40 adjacent the face of the liner 12, and thence to the charge: 10; In: the illustrated form of the invention, the resulting wave front patterns are similar to those shown in Fig. l, but it will be understood that they may be varied in: ac-- cordance with the factors above discussed. It should also be understood that the continuous sheet of'explosive 38 may instead be a plurality of spaced strips which will initiate explosion of the high explosive at a plurality of points around the opening 40.

The device illustrated in Fig. is similar to that of Fig. 4, except that the ogive 34 is replaced by a flat metal cap 42 which carries the fuse 36 and the sheet of explosive, indicated at 44 in this figure, and also serves to protect the contents until detonation.

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. An explosive shaped charge capable of producing a target pentrating jet whose penetrating force is de pendent on its velocity and density comprising: a cylindrical outer shell with an inwardly extending metal conical liner at one end and a fiat base at the other end, said conical liner having an inner apex, an outer base, and walls connecting said apex and base; a detonator positioned in the said flat base of said shell; a quantity of high explosive contained in said shell and surrounding said conical liner, said explosive being capable of producing detonation waves after detonation has been initiated by said detonator, said detonation waves collapsing said liner; and a cylindrical cup-shaped shield having a closed end, an open end and a circular wall therebetween embedded in said explosive between said shell and said conical liner with said open end of said shield surrounding said conical liner, the plane defined by said open end of said shield being parallel to the outer base of said conical liner and said plane being disposed between the apex and the base of said conical liner, said shield constituting means for directing the said detonation waves initially toward the walls adjacent the base of said conical liner thereby collapsing said conical liner progressively from its base to its apex thus increasing the velocity and density of said penetrating jet.

2. An explosive shaped charge as claimed in claim 1 wherein: said cylindrical outer shell has a circular wall connecting said flat base and the outer base of saidconical liner and said shield is disposed symmetrically with respect to said shell and said shield is so dimensioned externally that its circular wall and closed end are positioned closely adjacent to the circular wall and flat base of said cylindrical shell whereby the portion of the explosive separating said shell and said shield is in the form of a thin-walled cylinder.

3. An explosive shaped charge capable of. producing a target penetrating jet whose penetrating force is dependent on the velocity and density of said jet comprising: a cylindrical outer shell with an inwardly extending metal conical liner at one end and a flat base at the other end, said conical liner having an. inner apex, an outer base and a conical wall connecting said apex and liner base; a detonator positioned in the said flat base of said shell; a metallic cylindrical cup-shaped shield having a closed end and an open end disposed interiorly and symmetrically with relation to the axis of said outer shell; the' plane defined by said open end of said shield cutting the axis of said conical liner between the apex and base thereof, and the external parts of said shield being positioned adjacent the corresponding parts of said shell; a

main explosive charge disposed in the space defined by' disposed between the cylindrical walls of said shell and shield and between said closed end of said shield and said flat base of said shell, said priming charge being in contact with said detonator at one end of the shell and said main explosive charge at the other conical liner end of said shell whereby the detonation waves initiated in' said priming charge by said detonator may be transmitted to that portion of the main explosive charge disposed adjacently to the base and wall of said conical liner thereby collapsing said conical liner progressively from its base to its apex and thus increasing the velocity and density of said penetrating jet.

References Cited in the file of this patent UNITED STATES PATENTS 1,039,459 Sokolowski Sept. 24, 1912 2,628,559 Jasse Feb. 17, 1953 2,809,585 Moses Oct. 15, 1957' OTHER REFERENCES Technical Publication No. 2157, American Institute of Mining and Metallurgical Engineers, March 1947, pages: 1-16.

Behavior of Metal Cavity Liners in Shaped Explosive Charges, Technical Publication No. 2158, American Institute of Mining and Metallurgical Engineers, March 1947, pages 1-12.

Explosives with Lined Cavities, reprint from Journal of Applied Physics, vol. 19, No. 6, pages 563-582, June 1948.

Life magazine, October 23, 1950, pages 67-70.