EP0183892A1

EP0183892A1 - Seal for kinetic munition

Info

Publication number: EP0183892A1
Application number: EP85100647A
Authority: EP
Inventors: Avraham Makov
Original assignee: Israel Military Industries Ltd; State of Israel
Current assignee: Israel Military Industries Ltd; State of Israel
Priority date: 1984-12-04
Filing date: 1985-01-23
Publication date: 1986-06-11
Also published as: DK103885D0; IL73724A0; DK103885A

Abstract

A sabot projectile in which the rear portion is sealed off from the rest of the projectile by means of an annular seal (9) having at least two radially extending and centrosymmetrically arranged arms (10). The arms may be coplanar with the annular seal body, askew with respect to the central axis or located in a plane parallel to the annular seal body and linked thereto by linking pieces.

Description

The present invention concerns a sabot-type armor piercing, kinetic energy munition. Generally speaking such munition whose launchable component will be referred to hereinafter as "sabot projectile", comprises an elongated sub-projectile made of hard, armor piercing metal and partially enclosed within a segmented sabot whose segments are adequately hooped together, means being provided for a suitable interlock between the sabot segments and the sub-projectile to prevent mutual dislocation by the action of the propellant gases. The sabot is so designed as to impart to the sub-projectile the desired muzzle velocity and to separate neatly once the sub-projectile has left the muzzle, in consequence of aerodynamic and other pressure forces acting on the sabot.
In order to prevent damage to and premature separation of the sabot by the action of the propellant gases while the sabot projectile is still in the barrel of the launching weapon, it is necessary to provide for pressure tightness between the rear face of the sabot which is exposed to the propelling pressure and the remaining parts of the sabot projectile. According to the prior art this is achieved by applying a rubber coating on the rear end of the sabot, by injection of a sealing compound into the area to be sealed through specially provided axial and radial internal chambers, or some combination of these two methods. All these prior art methods have turned out to be inconvenient and cumbersome from a manufacturing point of view. Moreover, injection of a sealing compound into channels may result in air bubbles in the seal which would weaken the seal and possibly result in gas leakage under actual firing conditions. Furthermore, there is no reliable method of non-destructive testing of such seals.
It is therefore the object of the present invention to provide improved and simplified means for sealing of the rear of the sabot in a sabot projectile so as to prevent penetration of propellant gases between the sabot and the sub-projectile and between the sabot segments themselves.
In accordance with the present invention there is provided a sabot projectile comprising a penetrator-type sub-projectile partially enclosed within a segmented sabot having a rear portion adapted to receive the thrust of the propellant gases as known per se, characterised in that in front of said rear portion the sabot projectile comprises an annular seal with at least two radially extending and centrosymmetrically arranged arms, which seal is accommodated in a mating cavity comprising a circumferential groove in the body of the sub-projectile and bores in the sabot.
The arms may be coplanar with the annular seal, may form an angle therewith so as to be askew with respect to the axis of the sabot projectile or be located in a plane parallel to that of the annular seal and be linked to the latter by means of suitable linking pieces.
During operation the sealing effect of the seal in the sabot projectile assembly according to the invention is obtained by deformation of the seal as a result of the propellant gas pressure. Thus the seal adapts itself to the firing conditions.
When the sabot projectile according to the invention is fired and leaves the barrel muzzle of the launching weapon, the annular seal separates from the separating sabot segments and from the sub-projectile in consequence of aerodynamic forces.
The invention also provides for use in a sabot projectile assembly of the kind specified, a seal characterised by an annular body with at least two radially extending and centrosymmetrically arranged arms.
The number of arms may vary from 2 upwards and will depend on the general design of the sabot projectile assembly. For many purposes a 3-armed annular seal accommodated in a matching cavity has been found suitable.
The seal may be of any suitable material such as thermosetting elastomer and the like.
In accordance with the invention the properties of the seal can easily and reliably be checked before incorporation into the sabot projectile assembly. Moreover the simple shape and form of the seal in accordance with the invention lends itself readily to mass production.
The annular seal with its readily extending arms and the mating cavity in the sabot projectile may have any suitable profile such as circular, rectang- gular, quadrangular.
The invention is illustrated, by way of example only, in the accompanying drawings in which:

Fig. 1 is an elevation, partly in section of a sabot projectile according to the invention; and
Fig. 2 is a plan view of the annular seal thereof.

The sabot projectile here shown comprises a penetrator-type sub-projectile 1 and a segmented sabot 2 having three segments 3, two of which are shown in Fig. 1 while one is cut away, held together by aluminium hoops (not shown).
The outer surface of projectile 1 and the inner surface of sabot 2 are provided with intermeshing grooves 4 and in this way the sub-projectile and sabot are firmly interlocked so as to resist any relative dislocation in consequence of the propellant gas pressure on the sabot which, depending on the nature of the munition, is of the order of 4000 to 6000 bars.
The rer portion 5 of sabot 2 is fitted with a slipping obturator 6, e.g. of an elastomer adapted for cooperation with the rifling of the barrel of the weapon that launches the sabot projectile.
At its rear portion in front of the rear surface of sabot 2 the sub-projectile 1 comprises a circumferential groove 7 and coplanar therewith sabot 2 comprises three bores 8, the groove 7 and bores 8 together with the sabot wall portion surrounding the groove 7 forming together an annular cavity with three radially extending bores which accommodate an annular seal 9 having three centrosymmetrically arranged arms 10.
When the sabot projectile according to the invention is put together, seal 9 is first forcably slid on so as to snap into the annular groove 7 and thereupon the sabot is assembled around the projectile 1 such that each arm 10 is accommodated by one of the bores 8.
In the embodiment here shown each of radial bores 8 extendsacross the rear portion 5 of the sabot opening into the groove that accommodates the slipping obturator 6, which is particularly favourable from a manufacturing point of view. Each bore 8 is sealed by the slipping obturator 6.
Groove 7 may be of the same shape as those of the intermeshing grooves 4 which are on the sub-projectile 1, which simplifies production.

Claims

1. A sabot projectile comprising a penetrator-type sub-projectile partially enclosed within a segmented sabot having a rear portion adapted to receive the thrust of the propellant gases as known. per se, characterised in that in front of said rear portion the sub-projectile comprises an annular seal with at least two radially extending and centrosymmetrically arranged arms, which seal is accommodated in a mating cavity comprising a circumferential groove in the body of the sub-projectile and radial bores of the sabot.

2. A sabot projectile according to Claim 1, characterized in that the arms are coplanar with the annular seal.

3. A sabot projectile according to Claim 1 characterized in that the arms form an angle with the annular seal so as to be askew with respect to the axis of the sabot projectile.

4. A sabot projectile according to Claim 1 characterized in that the arms are located in a plane parallel that of the annular seal and are linked to the latter by means of linking pieces.

5. For use in a sabot projectile as claimed in claim 1, a seal characterised by an annular body with at least two coplanar, radially extending and centrosymmetrically arranged arms.

6. A seal according to Claim 5 characterized in that the arms are coplanar with the annular body.

7. A seal according to Claim 5 characterized in that the arms are askew with respect to the annular body.

8. A seal according to Claim 5 characterized in that the annular body and arms are located in two parallel planes and each arm is linked to the annular body by a linking piece.