WO1990007094A1

WO1990007094A1 - Expulsion projectile

Info

Publication number: WO1990007094A1
Application number: PCT/AU1989/000528
Authority: WO
Inventors: Brian Edmund Walsh
Original assignee: Commonwealth Of Australia
Priority date: 1988-12-14
Filing date: 1989-12-08
Publication date: 1990-06-28
Also published as: FR2640368A1; BE1002991A4; IT8922678A0; IT1237892B; CA2005433A1

Abstract

A projectile having a housing (1) containing a rear cavity (2) for the receipt of a canister (3) to be rearwardly ejected after firing of the projectile. The rear cavity is closed by a closure assembly (11) consisting of an inner substantially rigid base member (13) and an outer relatively thin retaining plate (14) holding the base member in position and, in turn, held in position by a radially, inwardly directed flange (15) of the housing. The base member is of a smaller diameter than the retaining plate to thereby provide a mechanical advantage so that the retaining plate will more readily bulge outwardly so that its peripheral edge portion will be released from the confines of the radially, inwardly directed flange.

Description

EXPULSION PROJECTILE Technical Field

This invention relates to an expulsion projectile, and more particularly a projectile for training purposes where a full explosive effect, as required in combat situations, is not required, but detonation of a quantity of pyrotechnic is required to provide personnel with an indication of the results of firing of the projectile during training. The projectile may also be utilized to release items other than quantities of pyrotechnic, such as canisters containing flares or explosive devices which are required to be distributed. Background Art

In practice, the firing of a training projectile from a gun, cannon or like launching device or weapon, involves the use of a round of ammunition consisting of a cartridge.case containing a propellant ^" and also the projectile itself which are loaded in to the breach of the weapon, the projectile being loaded first followed by the cartridge case, and which upon firing ignites the propellant in the cartridge case to launch the projectile towards the desired target. With expulsion projectiles for training purposes, a canister of pyrotechnic (or high explosive) is contained within a cavity in the rear of the projectile, and together with a fuze, is held in place by a closure assembly for the cavity. The closure assembly must be sufficiently strong as to not rupture inwardly under the force exerted by the propellant gases in the cartridge case, but also sufficiently weak to rupture outwardly when the pyrotechnic spotting package in the projectile either functions or is ejected and the products of combustion of the pyrotechnic in the form of light (flame) and smoke provide an indication to personnel during training.

With one form of known expulsion projectile the closure assembly consists of a plug screw-threaded into the rear end of the projectile to close the cavity containing the pyrotechnic and the fuze or other payloads, but the force created by functioning of an expulsion charge or the detonation of the pyrotechnic has to be sufficient to shear the threads of the screw-threaded plug and in order to do so, the ejection force must be relatively large.

Disclosure of the Invention

It is therefore an object of the present invention to provide a projectile, the rear closure assembly or base of which can withstand the externally applied forces applied to the projectile when the round is fired, but which can be relatively easily rearwardly released from connection to the projectile using a minimum ejection force. The invention therefor envisages a projectile having a housing containing a rear cavity for the receipt of a canister to be rearwardly ejected after firing of the projectile, said rear cavity being closed by a closure assembly, said closure assembly including an inner substantially rigid base member and an outer relatively thin retaining plate holding the base member in position and, in turn, held in position by a radially inwardly directed, retaining means carried by the projectile housing and overlying a peripheral edge portion of the retaining plate.

During firing of the projectile, the external forces applied after deflagration of the propellant in the cartridge case are borne by the combination of the rigid base member and the retaining plate, whilst upon functioning of an expulsion charge or detonation of the pyrotechnic after impact with a target, or upon functioning of a time delay fuze in the cavity, the closure assembly is rearwardly ejected as the retaining plate bulges outwardly whereby its peripheral edge portion moves- radially inwardly to escape the confines of the retaining means.

Preferably said retaining means is a flange formed integrally with the projectile housing

Preferably the diameter of the base member is less than that of the retaining plate whereby the forces applied by its peripheral edge to the retaining plate are radially inwardly of the periphery of the retaining plate to provide a mechanical advantage such that the retaining plate more readily bulges outwardly to release its peripheral edge portion from the confines of the radially inwardly directed flange of the projectile housing without any plastic deformation of the plate.

Brief Description of the Drawings One preferred embodiment of the invention will now be described with reference to the accompanying drawings, in which:

Figure 1 is a cross-sectional view through the rear portion of a projectile in accordance with the preferred embodiment of the present invention; and

Figure 2 is a cross-sectional view taken along line 2-2 of Figure.1.

Best Mode for Carrying Out the Invention

In this preferred embodiment of the invention, the projectile comprises a generally cylindrical housing 1 tapering forwardly (not shown) to an inert tip or nose, and also tapering rearwardly as shown, to its rear end or base. The forward end of the projectile contains an elongate cylindrical cavity la, the forward end of which is closed by a conical tip member (not shown) .

The rear end of the projectile contains a rear cylindrical cavity 2 in which is inserted a thin walled aluminium canister 3 containing a pyrotechnic (or high explosive) , followed by a cylindrical nylon holder 4 bearing against the end of the canister 3 and which, in turn, has a rear cylindrical cavity 5 which receives a fuze 8» The orientation of the fuze is correctly aligned by means of an alignment pin 6 extending radially inwardly of the holder 4 to engage within a slot 7 extending longitudinally of the fuze 8. The holder 4 is, in turn, held in place via an annular spacer 9 and disc-shaped felt pad 10 to allow for any dimensional tolerances, and the whole assembly is completed by a closure assembly generally indicated as 11. The rear cavity 2 is stepped as 12 to provide a larger diameter portion 2a at the opening from the cavity 2, and the closure assembly 11 comprises a rigid steel, disc-shaped base member 13 bearing against the felt pad 10 and slidably received .within the larger diameter portion 2a of the cavity 2. The closure assembly 11 is completed by a thin outer aluminium retaining plate 14, the circumferential peripheral portion of which is held in place by a radially inwardly directed circumferential flange 15 forming part of the rear end of the housing 1 of the projectile.

In the embodiment described, upon launching of the projectile from the weapon by means of deflagration of the propellant in the associated cartridge case as previously described, the external forces applied to the rear or base of the projectile are borne by the closure assembly 11, and in particular the rigid base member 13, so as to prevent actuation of the fuze 8 and premature detonation of the pyrotechnic in the canister 3. However, upon impact of the projectile with the target the impact forces will cause actuation of the fuze 8 and detonation of the pyrotechnic within the canister 3 causing an expansion of the products of combustion of the pyrotechnic within the rear cavity 2 to act on the assembly of holder 4, spacer 9, pad 10 and closure assembly 11 and cause the assembly to be rearwardly ejected from the projectile with the combusting pyrotechnic resulting in the production of light (flame) and sound to indicate to personnel the point of impact of the projectile with the target. In order to eject the rear assembly, all that is required is that the retaining plate 14 disengage from within the inwardly directed flange 15 of the projectile housing, and this is merely achieved by the base member being rearwardly forced against a retaining plate to cause it to bulge outwardly whereby its peripheral portion moves radially inwardly without any plastic deformation and its diameter decrease to a size less than the internal diameter defined by the flange 15. It will be apparent that the internal force required by detonation of the pyrotechnic is considerably less than the external force required during deflagration of the propellant in the associated cartridge case to launch the projectile, and thus considerably less ejection force is required than is the case with known projectiles. In addition, as the diameter of the base member 13 is less than the diameter of the retaining plate 14, the mechanical advantage achieved by the peripheral edge of the base member being applied radially inwardly of the peripheral edge of the retaining plate 14, reduces the force required to bulge the retaining plate and disengage its peripheral edge portion from the confines of the flange 15 of the projectile housing.

As an alternative to utilizing the projectile in a training exercise, it may also be used to rearwardly eject other items such as canisters or clusters of other military items such as flares to illuminate the surrounding .area, or explosive devices to be distributed over a predetermined ground area, and in that respect the rear cavity may contain a quantity of propellant material adapted to be ignited by a fuze having a pre-selected time delay function to achieve rear ejection of the items in question at a predetermined point in the flight of the projectile.

Claims

CLAIMS :

1. A projectile having a housing containing a rear cavity for the receipt of a canister to be rearwardy ejected after firing of the projectile, said rear cavity being closed by a closure assembly, said closure assembly including an inner substantially rigid base member and an outer relatively thin retaining plate holding the base member in position and, in turn, held in position by a radially inwardly directed retaining means carried by the projectile housing and overlying a peripheral edge portion of the retaining plate.

2. A projectile as claimed in Claim 1, wherein said retaining means is a flange formed integrally with the projectile housing.

3. A projectile as claimed in Claim 1 or 2, wherein the diameter of the base member is less than that of the retaining plate, whereby the forces applied by the peripheral edge to the retaining plate are radially inwardly of the periphery of the retaining plate to:, provide a mechanical advantage such that the retaining plate more readily bulges outwardly to release its peripheral edge portion from the confines of the radially inwardly directed retaining means without any plastic deformation of the plate.

4. A projectile as claimed in any one of the preceding claims, wherein a fuse holder is positioned between said canister and said closure assembly, and has a fuse cavity therein for receiving a fuse.

5. A projectile as claimed in Claim 4, wherein the fuse is aligned within said fuse cavity by means of a radially extending alignment pin through the wall of the fuse holder and engaging within a slot extending longitudinally of the fuse.

6. A projectile substantially as hereinbefore described with reference to the accompanying drawings.