IL33703A

IL33703A - Explosive shell

Info

Publication number: IL33703A
Application number: IL33703A
Authority: IL
Original assignee: Bofors Ab
Priority date: 1969-01-20
Filing date: 1970-01-14
Publication date: 1973-11-28
Also published as: ES375612A1; CH501888A; NL7000697A; DE2001754A1; FR2037318A5; IL33703A0; BE744615A; GB1245906A

Description

Explosive Shell Ε, η naive s ell ! I ! j I The present invention relates to explosive shells having| I shra nel material i.e. bursting charge placed between two j cylinders. i The Swedish patent specification 'No. 110,337 describes 1 'an explosive shell in which shrapnel in the form of hardened : balls is placed between an inner guide cylinder and the outer : surface of the body of the shell, and in which an explosive composition is housed within the guide cylinder.

. It. has been discovered that in order to obtain the greatest possible effect the shrapnel, in the form of balls for instance, must be imparted a very high initial velocity and that to this end. the explosive composition within the shell must act on the shrapnel material as effectively as possible. Furthermore, in modern shells a very high rotary velocity of j the shell is obtained, in some cases reaching to 30 000 r/m. It is therefore obvious that the shrapnel will be · sub ,-jected .'to large mass forces and the shell must be so constructed that !there is no risk of the shrapnel leaving the shell, as a re- ; suit .'of the mentioned mass forces, before 'the shell explodes.' Upon examining the construction . known from the Swedis ' patent specification 110,33'/ with regard to the aforegoing the following conclusions are reached: I Because the ball-shaped bursting charges lie within the outer wall of the shell it is obvious that if the balls are to be retained within the' shell in ' an effective manner this wall must be heavily dimensioned, to enable it to take up the axial forces acting thereupon - the inner guide sleeve does not assist in this respect.

As a result of the robust design of- the outer wall a coiri- paratively strong resistance is obtained to the ejection of the balls from the shell when it is exploded by the ex losivej located therein. i I I The inner guide sleeve, which lies between the balls andj ' I i the explosive substance, acts as a very incomplete propelling ί ' ·. 'surface for the balls as a result of its relative weak dimen-: ! sioning.

I 9 I The present invention is therefore- related to an explo- 1 sive shell of the type in which the pre shaped body of shrap- ' nel material is placed between two sleeves and within the in-- ner of whic! sleeves there is provided an explosive' substance', •and which is intended to rotate at high speed when fired.

The invention is mainly characte ized' in that the inner ■ cylinder comprises. an integrated ■ portion of the. actual 'shell.; body- and is dimensioned to. transmit a ■ portion of the axial 'forces occurring when, the, hell is fired, while the outer . jcylinder is dimensioned to transmit .the maximum stresses I occurring as a result of centrifugal force and also to-co-ntrij- ;bute towards absorbing the aforementioned axial forces,- and, ; I furthermore, to retain the shrapnel- material in the shell' .. ,. i.d-uring passage of the same through the air. j An embodiment of the invention will now be described in i I more detail with reference to' the accompanying drawing-, . addi- -;tional characteristic features of the ' invention being disclosed j in con junction- herewith. The drawing shows an explosive shell ^according to the present invention mainly in section.

The shell illustrated in the drawing comprises a front portion 1 provided with a fuse, which, for instance, may be a sorcalled proximity fuse. This portion of the shell, how-! ever,, does not constitute part of the present invention and ! will .not therefore be described in detail. The front portion! i j'l of the shell is joined in a suitable manner, normally by j screw joint, with the rear portion, which is indicated generally by the reference numeral 2.

The rear portion 2 comprises a shell body having a •connecting portion 3 which is in contact with the propelling j gases and which is provided with a copper driving band 3a ' dapted to guide the shell in the rifling of the barrel. In 'the exemplary embodiment, the portion 3 continues in a direcJ tion towards the front. end ·οί' the shell and in front of the copper drive band 3a' through an integrating portion k- in the cylinder form of an inner metal »te-e*v-e of such wall thickness that • . cylinder — * : the sie v^ . + is capable of absorbing and transmitting to the 1 front portion of the shell the axial forces occurring when j the shell is fired. As a result of its intended function the ' ' " ί linner cylinder k- obtains considerable wall thickness and,, ' in ■ i contradistinction to the case of the weakly dimensioned innerj Ί : guide cylinder of the aforementioned patent specificationj j jwill act as a very effective propelling surface. The. forward ; jend of the inner cylinder may be .provided with a thickened, j annular portion } .the purpose of which will be described in j ■ ' ■ i the following. . j Positioned outside the inner cylinder k is the preformed| shrapnel material 8, which preferabl comprises balls made ofj a metql of high density. These balls are conveniently held to}- gether in a bed of some suitable plastic material, e.g. an ester resin, so that the preformed shrapnel material is present in the form of a plastic cylinder with the balls bedded therein. The dimensions of the preformed portion 8 are such that during manufacture of the shell said portion can be pushed onto the inner sleeve leaving a small clearance therebetween.

Outside the preformed shrapnel material is an outer metal cylinder 7 which has the double purpose of. contributing towards transmission of the axial forces occirring when the j shell is fired and, above all, of retaining the shrapnel ma- ' !terial.8 in place during passage of shell through the air i against the forces acting as a result of the rapid rotation .[ j of the shell. ■ 1 ! , In order to obtain a maximum effect from -the shell, it "· ! has been shown to advantage to allow the inner cylinder k to', ' take up the major portion of the axial forces and- to allow ' ; ; the outer cylinder to take u 'the remaining, minor portion o.£ ; said axial forces, simultaneously as it retains the preformed shrapnel material. Since the- inner cylinder and. the outer j cylinder 7 together take up the axial forces, the inner cylinder*, k is able to act. as a very effective propelling surface and the outer cylinder 7 does not obstruct to any great extent exit of the shrapnel material. It has- also been, discovered- that an explosive shell of the aforedescribed type has a considerably much greater efi'iciency than an explosive i shell designed 'according to the afore me tioned Swedish patent} specification.

The outer, cylinder 7 i s- manufaqtured ' of high grade stee|l and in the case of shells having a diameter of ko mm has a wall 'thickne s of for instance 0.8 mm while, the inner cylin- der *+ has a wall thickness a proximately twice that of the j outer cylinder. During manufacture, the outer cylinder 7 is j i passed over the cylindrical, preformed shrapnel material 8, j which is previously fitted over the cylinder and has an ' ! outer diameter sufficiently large to permit it to fit over j j the cylinder 8 containing the shrapnel material, leaving a ; j small clearance therebetween. · [ I ; ■ To enable the outer cylinder / to parti 'cipate in trans ·- I " i i , mitting the axial forces., the cylinder in the exemplary erabo-r j.diment is secured between a shoulder 10 on the portion 3 and. , a shoulder- 11 on a ring 6, which is provided with internal > thread's engaging external threads on the ring portion 5, which in the exemplary embodiment · also is provided with internal threads to receive the front portion 1 of the shell. ■ As previously mentioned, because the two cylinders be-, 'tween, which the preformed shrapnel material Ls located, comprises element s which when the shell is fired together trans?- mit. the axial . forces to the fo ward portion 2 of the shell, · : and' because, the outer cylinder Ls adapted to retain- the pre-' formed, .-shrapnel material, it is possible to obtain, a . particu-. i'larly effectLve shell. In addition, manufacture of the shell is considerably simplified in that performed shrapnel material is used, •which is simply fitted onto the inner .cylinder and · then retained by the outer cylinder.

The interior of the shell Ls. filled in the normal- manner with' a. suitable :explosive. composition and does not form..part . of the invention, except to the extent that the .illustrated method of construction considerably increases the space available for the explosive.

It has been presumed in the foregoing that the two cylinders are made of suitable grade steel, although it is obvious that other materials which present the necessary •properties can be used.

The invention is obviously not restricted to the shown and described embodiment, which is given by way of example only, but may be changed v/ithin the scope of the claims. For instance, the shrapnel material need not necessarily be in the form of balls embedded in a plastic material but can be re-formed rings. or pre-formed cylinders .of metal of 'high density. ..

Claims

1. WHAT IS OLAIMEIP IS j lf An explosive shell of the type which has preformed shrapnel material positioned between two cylinders and which within the inner of the cylinders has an explosive substance and is adapted to rotate at high s eed when fired, characterised in that the inner cylinder (4) comprises the rear part of the shell as an integrating portion of the body (3) thereof the wall thickness of that portion being a multiple of the wall thiokness of the forward part of the inner cylinder, while the outer cylinder (7) is of a wall thickness equal t or less than the wall thickness of the forward part of the inner t : ' : ■.· cylinder, ¾Pha outer cylinder (7) being ssoured between a shoulder (10) on the rear portion (3) of the shell and a shoulder (ll) on an annular portion (6), which by means of a screw Joint is connected with the front, thickened portion (5) of the imvier cylinder ( ), the latter thickened portion (5) preferably serving to support the front portion (l) of the shell·

2. The shell claimed in the preceding claim, characterised in that the preformed shocapnel material consists in a known manner of' balls (fc) embedded in a plastic material to form a cylinder which can be fitted "tfnto the inner cylinder (4) and is adapted to receive the outer sleeve (7) as a member fitted onto the cylinder. f The shell of any of Claims 1-2, characterised in that the inner cylinder ( ) is given a wall thickness whioh is approximately twice that of the outer cylinder 5· An explosive shell* substantially as hereinbefore described and shown in