US2910000A - Hollow charge projectile - Google Patents

Description

oct. 27, 1959 E, w. BRANDT 2,910,000

HOLLOW CHARGE PROJECTILE 3 Sheets-Sheet 1 Filed Dec. 15. 1953 INVENTOR- E. VERA/VD r ATT RNEYS Oct. 27, 1959 E. w. BRANDT HOLLOW CHARGE PROJECTILE 3 Sheets-Sheet 2 Filed Dec. 15, 1953 INVENTOR ATTORNEYS E. w. BRANDT HOLLOW CHARGE PROJECTILE Oct. 27, 1959 3 Sheets-Sheet 3 Figfio Filed Dec. 15, 1953' Eilllllllllill. P

ATTORNEYS United States Patent 2,910,000 I i :HoLLow CHARGE PROJECTILE Edgar William Brandt, Geneva, Switzerland, assignor to Anstalt fiir die Entwicklung von Erfindungen und I Gewerblichen Anwendungen Energa, Vaduz, Liechten- -steirr, a corporation of Liechtenstein: l t v Application December 15,'1953, Serial110,308,388

Claims priority, application. Switzerland December 30, 1952 '1 Claim. (Cl. '1i )2-56) This invention relates to a hollow charge projectile of the kind having a fuze adapted to transmit the fire to a rear detonator disposed in the explosive charge.

It is known that, irrespective of the perforatingpower which characterises a hollow charge projectile, the latter must retain its power even when the impact takes place at avery high angleof incidence 'and on a hard target (for example at an angle of 70 to the perpendicular), at which angle of incidence the fuz'e must still function reliably. 1

Moreover, it is known that the eifect of the hollow charge is at its maximum when the explosion takes place at the moment when the front end of the coveringis at a predetermined distance from the target. Hollow charge projectiles generally have at the front a thin casing which is crushed on impact.

When hollow charge projectiles are fired at high speed, only a very short space of time intervenes between the moment when the fuze touches the target and that at which the covering of the cavity arrives at that optimum distance. Y

It is therefore desirable to equip following three stages have'occurred before the covering has reached the aforesaid position:

' (1) Excitation of the rear detonator by the detonating priming at the front;

(2) Explosion of the main charge; and

(3) Formation of the perforating jet; moving at a speed of the order of l0,000 me'tres per'second.

These conditions must be brought about in'the absence of material obstacles inside and in front of said cone, which would otherwise form a baflie in the passage of the jet and divert'or disperse the same, thereby reducing its perforating action.

To this end, the fuze must have the additional function of destroying and dispersing the whole of its component parts and also the ballisticcap of the projectile on percussion, in order not to hamper the axial concentration and the passage of the metallic particles constituting the perforating jet;

It isknown moreover that the probabilities of hitting a moving target are the greater, the higher the mean speed of the projectile and, consequently, the shorter its time of travel. For a hollow charge projectile moving at high speed (for example 1000 metres per second) the end of the'fuze must be sufliciently remote from the base of the perforation cone for the optimum space between the target and the front end of the-covering to be provided at the time of the explosion'on impact;

Too long a fuze carried forward of the cap, however, may unfavourably influence the external ballistics of the projectile and impair accuracy of firing, so that it is advantageous to increase as much as possible both the speed of functioning of the fuze on percussion and the speed of transmission of the fire from said fuze to the rear detonator. 1

n such projectiles with a firing system having such rapid transmission that theice In order to effect transmission of the fire from the head fuze to the detonator, it has already been proposed to use either detonating cord passing through the per foration cone, or else shock wave transmission in the absence of any intermediate material element.

' The first solution, which isinteresting because of'the high speed of transmission obtained, has the disadvantage of adversely affecting the metal cone through the axial orifice of which transmission is effected andrat the same time reducing the power of the perforating jet. The second solution, which is satisfactory for projectiles the firing speed of which is low, is no longer so when applied to a projectile fired at high speed. The speed of the shock wave, of the order of 2,500 metres per second, is in fact then insufiicient for the explosion to occur at the required distance from the target and thus to achieve optimum perforation.

The present invention provides in ahollow charge projectile of the type comprising a percussion fuze functioning by inertia and by driving-in and fire transmission means adapted to transmit the fire to a rear detonator housed behind the perforation cone lining the cavity of said charge, a construction in which said means comprise a tubular body containing an explosive transmission column at the front end of which said fuze is fixed as a projectiom in front of a chamber ensuring its security against shock or dropping, by being driven back into said chamber, the tubular body and the explosive column that it contains being extended inside the projectile over the entire length of the ballistic cap of the projectile and' detonator, so that the functioning of the percussion ele-" ments of the fuze is so instantaneous, even with a high angle of incidence of impact on thetarget, and the weight of said elements is so low, that'the tubular body carrying the explosive charge undergoes no deviation before having functioned and effected the'transmission of fire to the rear detonator.

The afore defined construction has the advantageof obtaining the highest possible speed of transmission of; the fire from the head fuze to the main detonator, without risk of spoiling the metal cone, and at the same time permits the completest possible elimination of the inert elements which constitute the mechanical parts of the fuze and of the tubular body of the explosive charge and the ballistic cap of the projectile, which are expelled laterally in the form of small splinters, before the formation of the perforating jet, which latter can then produce the optimum effect on the target.

The speed of detonation of the explosive column, of-

mission of fire two to three times as rapid as that resulting from a shock wave transmitted in air (about 2,500 metres' per second), which latter is moreover rapidly braked on its path and becomes ineffective beyond a certain distance. .It is therefore understandable that the saving in time entailed by transmission by explosive column is further increased by the fact of the shortening of the distance of transmissionwhich, over the height of the cone, thus retains a mean'speed, higher than that whichit would have if it were efiected over a longer distance.

According to one embodiment of the invention and with a view to increasing the speed of transmission while favouring firing at a high angle of incidence of impact, the tubular body containingthe explosive column is extended, forward of the ballistic cap over a length proportionate to the speed of impact of the projectile at practical firing distances, thus constituting an antenna, from the end of which projects a percussion fuze of very small mass and the hard head of which, .havinga cutting edge, is adapted to bite into any target, even-those possessing great resistance. a

This arrangement of the fuze to form an antennaensures that, the greater angle of incidence of the projectile in relation to the perpendicular to the target grows, 'the smaller is the distance remaining to be covered by the projectile before its. explosive charge comes into contact with said target, that is to say the shorter'the time dur ing which the fuze must transmit fire to the main detonator, in order that the perforating jet arising from the explosion can be formed at the optimum distance from said target. Consequently, the speed of the projectile and its incidence of impact constitute two factors the effects of which are additive and in direct proportionwith which the speed of transmission of fire must increase.

The fuze-carrier antenna has an external diameter increasing from the front end towards the base by which it is fixed on the ballistic cap of the projectile. The mechanical resistance to deformation and decentering which said antenna might undergo in the course of transport and handling is thus reinforced.

The tubular body and the explosive column which it contains may be constructed of one or more sections joined toone another by screwing or otherwise, each section being supported by a thin wad which does not impair the speed of transmission of the fire.

Since thefuze contributes to a substantial degree to the speed and dependability of functioning of the assembly, the construction of the same must be defined. In accordance with the present invention, said fuze comprises a primer carrier open at the rear and acting at the same time as striker carrier, said primer carrier being housed in a fuze body which nests in the front part of a hollow fuze carrier constituting a cylindro-conical chamber of a height at least equal to that of the fuze, and the rear part of which, of a diameter decreasing from front to rear, ends (if desired with the interposition of a relay primer) at the top ofthe explosive fire transmission column.

The fuze body is preferably made of a material of greater density and strength than the other elements constituting the fuze, in order to promote, particularly by the effect of inertia, the correct guiding of the striker carrier in the fuze body, even with a large angle of impact.

The fuze has in addition a collar, the front part of which penetratesiinto the striker carrier, and the rear part of which, of greater .diameter, bears on a corresponding bearing surface on the fuze carrier and retains the primer in position while at the same time preventing the penetration of the primer carrier into the fuze carrler.

An elastic spacing member, made of metal or other material, for example a cor-k ring, is interposed between the percussion elements and holds the detonator away from the pointof the striker.

The .aforedescribed construction provides perfect safety in the event of dropping the projectile without it being necessary to add any supplementary member to the fuze, as will hereinafter become apparent.

According to a further feature of the invention, the

percussion head of hard material has a peripheralvgroove in which is gripped the front edge of the primer carrier, while the striker, which is conical in shape, bears by a part of its external surface on an annularbearing surface on the .primer carrier, so that the integral assembly comprising the percussion head and the striker is centered at two places. This has the result that, under heavy firing incidence, the striker, although fixed to project from the outside of the fuze body, remains sufficiently centered to operate the primer.

The part constituting the head and the body of the striker has a generally conical shape, thus constituting a solid of equal resistance, protected from accidental breakage or deformation on striking against the target, even at high speed or with a large angle of incidence.

Moreover, provision is made for reserving a peripheral space between the body of the striker and the striker carrier, with theobject of facilitating the driving back of the striker, at high impact speed, by deformation of the front part of said striker carrier, before the shearing of the rear collar. I

Although the shear-resistance of said collar is smaller than the crush-resistance of the striker carrier, the inertia of the latter, at high impact speed, is nevertheless such that it alone is driven back.

In order to enable the invention to be more readily understood, reference is made to the accompanying drawings which illustrate diagrammatically and by way of example, various-embodiments thereof and in which:

Figures 1 to 4 illustrate thefiring and the functioning of different hollow charge projectiles, with a large angle of incidence of impact on the target, shown inaxial section;

Figure 5 shows a projectile in accordance with the invention at the moment when its fuze reaches the target;

Figure 6 is a partial axial section of a hollow charge projectile in accordance with the invention;

Figure 7 illustrates on a larger scale and in axial section the fuze and the firing means of the projectile illustrated in Figure 6; V

Figure 8 is a modification, also inaxial section, of the assembly shown in Figure 7; and

Figures 9 to 13 illustrate, likewise in axial section and on a larger scale, various possibilities of operation of the fuze illustrated in Figures 7 and 8.

Figure 1 shows diagrammatically the normal operation of a hollow charge projectile (in broken lines), of which the perforating jet j issuing from the cone 0 under the effect of the explosion is concentrated axially and perforates the armour plate P struck by the projectile at a larger angle of incidence of impact.

On the other hand, as shown in Figure 2, the fuze of the projectile has not operated in time and the explosive charge, which has come into contact with the target, commences to crush itself against the latter, so that the hollow charge effect will be partial or may even not be achieved at all. v

The projectiles of Figures 3, 4 and 5 are illustrated at the moment when. the end of the fuze 1 reaches the target. In Figure 3 ,the transmission has to be effected from the primer m of the fuze to the detonator 2 over the total height of the ballistic cap b and of the cone 0, at the speed of about 2,500 metres per second, and the perforating jet must be formed before the projectile has travelled the distance x, which is the shorter, the greater the incidence of impact -(x is smaller than x for an incidence of impact on the plate P larger than the incidence on the plate P). v

If the speed of the projectile on impact is high, it is understandable that the length x (or x for the incidence corresponding to the plate P) will be travelled .in too short a space of time for the transmission of the fire and the hollow charge phenomenon to take place in time.

, According to one feature of the present invention, which is illustrated in Figure 4, it is possible to increase the distance x (or x) by mounting the fuze to project from the end of a tubular body, one part of which constitutes an antenna forward of the ballistic cap b of the projectile, said tubular body enclosing an explosive column having a high detonation speed (7,000 to 8,000 metres per second);

The transmission of the fire is then effected over the d. Experience however has shown that the rear end of the tubular body must not pass beyond the base of the Figure 5, optimum conditions are attained when the part,

of the explosive column inside the projectile extends substantially over the length of the ballistic cap.

The projectile illustrated in Figure 6 (the rear part of which has not been shown) comprises a fuze, the head 1 of which projects from the end of a fuze body 2, which is nested in the fuze carrier 3, which in turn is fixed in the head of a tubular body 4, the parts 1, 2, 3 and 4 constituting an antenna mounted forward of the ballistic cap 5 of the projectile. The tubular body 4 is extended into the interior of the projectile, substantially over the entire length of the ballistic cap 5. Said tubular body may comprise a plurality of sections 4, 4a, 4b, screwed one into the other, and contains in its interior an explosive column formed of the elements 6, 6a, 6b (see Figure 7).

The hollow explosive charge 7 and a relay charge 8 are housed in the body 9 of the projectile. A metal cone 10 lining the cavity of the charge 7 is open at its apex facing a detonator 11 housed in the relay charge 8. The ballistic cap 5, having an external screw thread at its base, is screwed into the body 9 of the projectile and, through the medium of annular packings 12, holds in position the explosive charge 7 and the cone 10, at the same time as it immobilises a conical part 13 centering the tubular body 4.

The explosive column 6 preferably consists of compressed explosive, for example penthrite, hexogen or derivatives thereof. As shown in Figure 7, thin wads 14, 15, interposed between the elements 6, 6a, 6b of the explosive column serve as wedging or retaining means and prevent said elements from moving back under the eifect of the acceleration on the firing of the shot or from being displaced during transport and handling, in the corresponding tubular sections 4, 4a, 4b.

The section 4b is terminated by a detonating primer 16 having a slightly concave base,'constituting a small charge known as a flat charge, the transmission of fire from which is directed and more rapid than that of an ordinary primer.

Moreover, depending on the consistency and the density of the explosive in the tubular body 4, the latter can be made in one piece, :as shown in Figure 8, and obturated at its rear mouth, if required, by a metal cone 18 forming a plug adapted to ensure rapid transmission of fire to the detonator 11 by a hollow charge effect.

The fuze of the projectile illustrated in Figure 7, and on a larger scale in Figure 9, comprises a striker carrier 19 serving at the same time as a primer carrier and enclosing in its rear part a detonating primer 20, which is retained at the front side by a cork ring '21. The latter is adapted to contract after the manner of a spring when percussion is effected by inertia and the primer 20 is thrown on to the tip 22 of the striker. The head 1 of the striker, which is made of a harder material than current armour, comprises a cutting edge 23 which bites into the target on impact.

The striker carrier 19 has a hollowed shape, pierced at its centre forward of the primer 20, the conical tip of the striker taking up position inside the hole provided and being centered at 24 on a slightly widened out bearing surface. The striker 25 has at the front a groove 26 which is gripped by the front edge of the striker carrier 19, so that the striker is retained and centered striker carrier 19, facilitates the driving of the striker on impact, as will hereinafter be explained.

The detonating primer is retained at the rear required through the medium of a flexible washe 28) on the base of a collar 29, a part of smaller diameter of which collar penetrates into the primer carrier 19. The rear part of the collar 29, of larger diameter, rests on an internal bearing surface of the fuze body 3. I The striker 7 carrier 19, housed in the fuze body 2',is retained therein by crimping the front edge of the latter, and the two parts thereof are respectively in contact by their base with the collar 29, being thus maintained in position in the fuze carrier 3. A free space 30, serving as safety chamber, is reserved behind the collar 29. The slightly conical part 31 of the chamber 30 has a diameter decreasing from front to rear and ends through a passage 32 over an intermediate primer 33 at the head of the explosive transmission column 6. It will be noted that the primer 33 (Figures 7 and 8) can be dispensed with, in which case the passage 32 opens directly on to the explosive column 6.

The hereinbefore described fuze functions as follows:

At rest, the respective elements constituting the fuze are disposed as shown in Figure 9.

In the event of accidental dropping of the projectile on its head from a suflicient height (Figure 10) the collar 29 is sheared at its base, at the same time as the front of the fuze body 2 is deformed and crushed, thus absorbing the shock on the projectile. The fuze is then progressively arrested in the narrowed part 31 of the chamber 30. If in falling the projectile should fall with its rear part foremost, the collar 29 is sheared by inertia, as shown in Figure 11, and the fuze, penetrating into the safety chamber 30, is braked in the part 31 of reduced diameter. Whatever the position of the projectile when dropped, therefore, the safety of the fuze is assured and percussion cannot occur.

The functioning of the fuze on the target as illustrated 30, while the primer 20, continuing its movement, is

thrown against the point 22 of the striker. If the impact occurs at high speed (Figure 13), the striker carrier 19 is crushed and the tip 22 of the striker reaches the primer 20, even before the collar 29 has been sheared.

Irrespective of the mode of percussion, the fire is transmitted from the detonating primer 20 to the explosive column 6, then through the cone 10 to reach, within a minimum space of time, the rear detonator 11, which communicated the explosion to the hollow explosive charge.

It is understood that the invention has been described only by way of example and that various modifications can be made thereto without departing from the scope of the invention defined by the appended claim.

What I claim is: v

In combination with a hollow charge projectile comprising a body, an explosive charge in said body, a balfire to said main detonator, said means including a tubular housing carried by said ballistic cap, a fuze fixed at the front end of said tubular housing, an explosive column in said housing, a chamber in said tubular housing between said fuze and said explosive column, said fuze comprising a deformable striker-carrier mounted on the front end of the tubular housing, a substantially conical striker having an integral end portion and an intermediate peripheral groove by which the striker is held by the strikercarrier, an inner annular bearing portion on said strik'ercarrier, said striker resting in central position on said bearing portion, said striker being separated from the striker-carrier by a peripheral space in front of said bear- 1,597,499 Rushmere Mar. 18, 1919 8' Wfight Apr. 12, 1921 Remondy Mar. 31, 1925 Remondy Nov. 17, 1925 FOREIGN PATENTS Great Britain May 22, 1946

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