WO1986001280A1

WO1986001280A1 - Macrogranular gun propellant charge

Info

Publication number: WO1986001280A1
Application number: PCT/AU1985/000186
Authority: WO
Inventors: Robert Charles Warren
Original assignee: The Commonwealth Of Australia Care Of The Secretar
Priority date: 1984-08-08
Filing date: 1985-08-06
Publication date: 1986-02-27
Also published as: EP0192670A1

Abstract

A macromolecular gun propellant charge comprising a block (1) having an elongated body of propellant with longitudinal spaced apart channels (2) extending therethrough, which the charge is arranged as a macromolecular block (1) of cylindrical shape adapted to fill the bore (8) of a cylindrical propellant chamber (7).

Description

"MACROGRANULAR GUN PROPELLANT CHARGE"

This invention relates to improvements in and to gun propellant charges, and in particular it relates to a macrogranular charge.

5. Gun propellant charges usually consist of a large number of small elongated grains or members, each with one or more axial perforations, or bundles of sticks which are usually the length of the charge containing part of the cartridge case and. are packed longitudinally.

10. The prior art using packed perforated members may be appreciated by reference to United States Letters Patent No. 4,094,248 assigned to the United States of America as represented by The Secretary of the Army, in which a propellant charge is assembled by stacking together a

15. plurality of extruded longitudinally grooved and channeled polygonally shaped propellant grain_s , the object being to provide for nearly full utilisation of the circular volume of the propellant chamber. The purpose of the multiplicity of channels is to among other things give a near constant

20. burning rate as opposed to a single specially shaped central channel .

In the Specification of United States Letters Patent No. 3779819 JeanPierre Thomas et al assigned to the Society National des Poudres et Explosifs, Paris a block of 25. explosive material is formed in two half sections with particularly shaped configuration and a longitudinal groove channel between the two sections.

In the Specification of United States Letters Patent No. 4291624 Udo Sabranski assigned to Rheinmetall 30. GmbH, of Duesseldorf, an explosive charge block is shown, having air cavities in the explosive material situated to guide the propogation of the shock wave produced by detonation in a predetermined direction. The prior art however, while acknowledging the general art of explosive charges moulded as blocks with directional cavities, does not disclose the principle of moulding a block of unitary construction formed in a sin 5. piece and having a plurality of spaced channels to contr burning, the block being dimensioned to neatly fit the b of the device in which it is used. Prior art does not al the ready distribution of additives which can be advanta ously placed in the single block over any part of its ar 10. whereby to achieve the improved results obtainable from present invention.

The object of the present invention is to produce a improved gun propellant charge in which greater control reproducibility of charge dimensions, and hence more 15. reproducible ballistics are obtainable, and also to gain increase in charge volume and hence better ballistic performance.

Further objects are to obtain easier ignition, the elimination of the need for deterrent coatings, and the 20. ability to place additives such as flash suppressors or wear inhibitors in locations where their action can be optimized.

The invention comprises a macrogranular gun pro¬ pellant charge comprising a block having an elongated bo

25. of propellant with longitudinal spaced apart channels extending therethrough characterised in that the said charge is formed of propellant grains arranged to form a block of cylindrical shape adapted to fill the bore of a cylindrical propellant chamber, the -said block having a

30. plurality of longitudinally positioned spaced channels t said cylindrical block preferably having additives dispersed in the charge at selected localities whereby t control the action of the additives in relation to selec areas of the charge during burning. The invention includes a method of manufacture and use.

Further features of the invention are coaxial alignment of a plurality of blocks, and register means to axially align the channels in adjacent blocks.

To enable the invention to be appreciated some 5. embodiments thereof are described with reference to the accompanying drawings in which:-.

FIG. 1 is a perspective view of a pair of macro- granular gun propellant charge blocks placed end to end according to this invention, showing part of the first 10. block in section to show how the holes extend through the blocks and align, in adjacent blocks,

FIG. 2 is a fragmentary view showing how two such blocks can be placed end to end but showing an independent interface orientating member between the blocks, and

15. FIG. 3 shows how such a block fits into a propellant chamber in say a cartridge, only one block being shown.

As shown in FIG. 1 the macrogranular propellant charge block 1 forming the invention is of circular form to fit the chamber of a barrel or member in which it is

20. intended to be used is dimensioned to fill the space so that there is no need to assemble a series of members as in the prior art. This enables the block 1 to have a cross-sectional design which placed the longitudinal channels 2, as well as any additives, at the most con-

25. venient position in the block both for smoke prevention or reduction and for barrel protection and the like.

The block can be of any required length but if desired it can be used in multiple arrangement as shown in FIG. 1 where a pair of blocks 1 and 1A are placed end to end, register means 3 being provided, the register means 3 being a socket engaged by a tongue 4 formed respectively on the blocks 1 and 1A. This gives the correct orientation 5. to the blocks 1 and 1A to line up the channels 2 through which the required gas circulation and gas flow takes place.

In the form shown in FIG. 2, two blocks 1 and 1A are connected by an interface member 5 again apertured in the required manner and carrying register means in the form 10. of tongues 4A engaging sockets 3A in the blocks.

It will of course be obvious that the orientation can be effected by various means provided the means are so arranged that the channels 2 in the blocks 1 and 1A are correctly lined up for the required action.

15. It would of course also be possible instead of distributing an inhibitor 6 in the block in a .particular manner, such as around the edges as shown in FIG. 1, to have the interface block formed of such a material, or formed to include such a material, but the distribution

20. could be achieved by moulding the block 1 with longitudinal bands containing inhibitor which can take any required form and these bands could be peripheral as shown at 6 in FIG. 1 or could be at particular interval locations such as surrounding or lining the channels 2 to thereby be

25. associated with the surface of the block 1 or with the surface of the longitudinal channels 2 depending on the purpose required and whether an inhibitor or an additive is used. In FIC. 3 the propellant chamber is designated 7 and the bore in which the charge is held is designated 8 and it will be noted that the macrogranular block 1 completely fills the diameter of chamber 7.

5. As stated earlier, in FIG. 1 the peripheral area 6 represents an additive such as a combustion control substance or a bore protection medium but this can be variously positioned depending on where it is most effective. Also a smoke inhibitor can be placed where best

10. suited to control smoke minimisation during the burn, because it will be realised that with a block which fills the propellant chamber, selection of the position of additives is enhanced and the additive can be positioned at any part of the block as for instance by adding the

15. additive during extrusion or moulding of the block.

Thus according to the present invention the propellant charge consists of a block 1 of generally -cylindrical cross section with a series of spaced longitudinal channels through it for burn control, and a series of such blocks

20. can be used to form a stack of such blocks placed end to end blocks each with a plurality of channels in the axial direction generally symmetrically spaced in cross section, the block or blocks having a diameter to neatly fit a cylindrical propellant chamber of a gun or gun cartridge or

25. the like to which the solid propellant is to be applied.

By use of such an arrangement maximum use of the space available is made and the propellant is in the form of a solid body extending across the dimensions of the chamber in which it is housed and has the multi- 30. plicity of longitudinal burn control channels spaced to best advantage, the length of the propellant charge blocks being such as to completely fill the space in which the charge is housed, or as said a series of blocks can be used end to end to fill the space but with each block itself of a cross sectional dimension to neatly fit the diameter of the bore which receives the propellant charge block or blocks. An additive can be positioned anywhere over the 5. whole cross-sectional area and could be associated with areas central or outward in the block as by moulding or extruding a complete block such placement can be readily selected.

By such an arrangement the advantages sought are 10. obtainable in that the propellant charge block can be designed for maximum effect as it occupies the sole cross sectional area of the propellant chamber and the longitudinal holes can be formed in their maximised positions and in the case of where a series of blocks 15. are used end to end register means can be included to ensure correct positioning of the longitudinal holes if for instance they are to be continuous in the final assembly.

It will be realised if a smoke inhibitor, corrosion 20. inhibitor, combustion control substance, flash suppressor or wear inhibitor is to be added this can again be selectively placed at the outer surface of the propellant charge or at selected internal positions, such as at the channels, where it may achieve maximised results, or such a 25. material may be included in an interface between blocks of a multi-block charge or incorporated Into the pro¬ pellant, at any selected area and does not interfere with the general explosive action of the propellant charge, or the simplified loading of charge into a chamber, cartridge 30. or the like. Thus a simple and effective charge is provided which is moulded or extruded in a form to fit the length of a chamber when a single block is used and of a cross sectional dimension the same as the chamber or alternatively 5. a series of successively placed propellant charges can be used arranged end to end in the space and^' each conforming the the dimensions of the chamber, to thereby avoid the need of stacking bundles of sticks as exemplified for instance in the prior art, and ensuring that the 10. best results are obtained from the solid propellant charge .

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. A macromolecular gun propellant charge comprising a block (1) having an elongated body of propellant with longitudinal spaced apart channels (2) extending therethrough characterised in that the said charge 5. is arranged as a macromolecular block (1) of cylindrical shape adapted to fill the bore (8) of a cylindrical propellant chamber (7) and having a series of spaced longitudinal channels (2) extending through it whereby to achieve maximum charge volume and burning.

2. A macromolecular block according to claim 1 characterised in that the said cylindrical block

(1) has additives (6) dispersed in the charge at selected localities whereby to control the action of the additives 5. ( 6) in relation to selected areas of the charge during ignition.

3. A macromolecular gun propellant charge according to claim 1 or 2 characterised in that the said block

(1) has at Least one end arranged to allow stacking of a plurality of blocks (1-1A) in a coaxial extension.

4. A macromolecular gun propellant charge according to claim 2 characterised by register means (3-4) on the said block (1) to select orientation of the said blocks (1-1A) when stacked end to end, said register 5. means (3-4) being positioned to cause the said channels

(2) to be co-extensive in the said blocks (1-1A).

5. A macromolecular gun propellant charge according to claim 2 characterised by register means (3-4) comprising a socket (3) on at least one end of one said block and a matching tongue on at least one end of an adjacent 5. block.

6. A macromolecular gun propellant charge according to claim 3 characterised by a pair of blocks (1-1A) and by an interface member (5) placed between them and having register means (4A) to engage register means (3A) on the blocks (1-1A) and having channels to register with the channels (2).

7. A macromolecular gun propellant charge according to claim 6 characterised in that the interface member

(5) contains an additive.

8. The method of applying a macromolecular gun propellant charge as defined in claim 1 which consists in moulding a propellant into a cylindrical block (1) of one piece having longitudinal channels formed through it and dimensioned to fill the bore of a cylindrical chamber, placing the said charge in a propellant chamber into which it neatly fits, and activating the charge.

9. The method of forming a macromolecular gun propellant charge as defined in claim 1 which consists in extruding a propellant into a cylindrical block

(1) of one piece having longitudinal channels formed through it and dimensioned to fill the bore of a cylindrical chamber, placing the said charge in a propellant chamber into which it neatly fits, and activating the charge.

10. The method of claim 9 or 10 characterised by including an additive in the said cylindrical block at a selected locality.