AU778762B1 - A composite propellant charge - Google Patents

Description

p C'OMMO NWE ALT H OF AU S TRA LI A PATENTS ACT 1952 COMPLETE SPECIFICATION (Original) FOR OFFICE USE Class Int. Class Application Number: Lodged: 6omplete Specification Lodged: Accepted: Published: Priority: Related Art: 9'ame of Applicant: ."A~ddress of Applicant: ECf1JIfY P TAE 01 UJVL iAtT& NE)THERNAUI D4AECtN GvRIIU Y CTr Ad Whitehall, London, England 0 0 AcLtual Inventor(s): GEOR'GE JAMES

STUBBS

00 0 :90 of 0 Address for Service: DAVIES COLLISON, Patent Attorneys, 1 Little Collins Street, Melbourne, 3000.

Complete specification for the invention entitled: "A Composite Propellant Charge" The following statement is a full description of this invention, including the best method of performing it known to me

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la A COMPOSITE PROPELLANT CEARGE This invention relates to composite propellant charges for launching projectiles from gun barrels, which charges are particularly, but not exclusively, applicable to guns having automatic charge handling systems.

It is generally necessary for artillery to carry a range of charges of different energy levels for example to achieve different ranges. A logistically efficient way of providing the required selection of energy levels of propellant charge is to supply identical composite charges each comprising a collection of individual incremental charges one or more of which can be removed to reduce the composite charge to the required strength. In this way one design of composite charge can provide for all a gun's charge requirements.

15 A known composite charge comprises a canvas main charge bag containing several,.separately bagged incremental charges of various explosive energy each of which can be removed manually from the main charge bag by means of a loop of canvas sewn on to each incremental charge bag to reduce the composite charge to the required energy.

20 The remaining charges in the main charge bag can then be loaded into the gun chamber behind a previously rammed projectile.

If the size of the propellant charge needed to engage a particular target is known sufficiently far in advance of engagement the required number of composite charges for the engagement can be prepared in advance. The maximum firing rate will then usually be determined by the rate of which the charge bags can be loaded into the gun barrel. However, if the required charge size can be determined only a short time before engagement of the target, that is when the target is an "instant target", the charges have each to be prepared immediately before loading. This greatly reduces the maximum firing rate of the gun if a charge less than the full composite charge is needed. To provide a gun with a significantly higher maximum rate of fire against instant targets it is necessary to automate the preparation of the composite propellant charge.

Known composite charges are not suitable for use in such an automated system because the flexibility of the main charge bag makes handling awkward and the incremental charges are difficult to locate and remove.

It is an object of the present invention to provide a composite charge more suitable for use in an automated charge handling, preparation and loading system. It is a further object to provide a composite charge that can be manually prepared so that the composite charge is also usable in non-automated charge handling systems and so can be issued as a standard charge for a range of automated and non-automated artillery.

Accordingly, there is provided a composite propellant charge for launching a projectile from a gun barrel which includes an elongate, rigid carrier having a first and a second longitudinal carrier extremity and at least one elongate incremental charge removably located adjacent the carrier, the incremental charge being 15 substantially parallel to the carrier and extending no further than the first or second carrier extremity.

The carrier may contain a propellant charge thereby forming a basic charge on which are removably located the incremental charges.

Because the incremental charges lie between the extremities of S, 20 the carrier the overall length of the composite charge is not altered by their removal. This feature, together with the rigid nature of the carrier, ensures that the extremities of the composite Scharge are fixed relative to each other so that an automatic handling system configured to manipulate the composite charge by its extremities can operate identically for all charge configurations.

Because the incremental charges are positioned about the exterior of the carrier they are readily locatable by an automatic stripping mechanism as well as being accessible for manual stripping.

Preferably the carrier comprises a support and a first and a second cylindrical end member arranged so that the composite charge can roll on a planar surface whether or not any of the incremental charges have been removed. This allows the use of ramps to transfer the composite charges from one station to another during the automatic preparation and loading thereby simplifying the transfer mechanism.

Conveniently the end members may include end caps which engage the incremental charges to locate them adjacent to the basic charge, the end caps being structurally weakend so that individual incremental charges can be removed from the remaining incremental charges.

Embodiments of the invention will now be described, by way of example only, with reference to the accompaying drawings in which Figure 1 is a cut-away view of a composite charge according'to the present invention, having three incremental charges removably located adjacent to a basic charge by a pair of end caps, the charge being viewed in the direction I of Figure 2; Figure 2 is a cross section of the composite charge shown in .i Figure 1 along the lines II-II of Figure 1; Figures 3 to 6 are schematic cross sectional views of the 15 composite charge shown in Figures 1 and 2 along the line III-III of Figure 1 showing a method of removing the incremental charges from s the basic charge by a stripping pawl;

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stee Figure 7 shows a cross sectional view of the end cap of a further emdobiment having an alternative igniter charge arrangement; Figure 8 shows a cross sectional view of the end cap of a yet O"l further embodiment in which the support supports the end cap against ]inward flexure; Figure 9 is a schematic cross sectional view of the end cap of Oslo** a further embodiment in which the end cap is castellated; and Figure 10 is an end view of an end cap of a further embodiment of the invention.

Referring to Figures 1 and 2 there is shown a composite charge two comprising a carrier 4 and three incremental charges 6. The carrier 4 comprises a combustible open ended charge case 8 constituting the support, of a kraft based material having a generally equilateral triangular cross section with rectangular sides 10 and a first and a second combustible end cap 20 and 22 constituting the end members. The end caps 20 and 22 have tubular side walls 24, 26 and discoid tops 28 and 30 one end cap 20 and 22 mounted on a respective extremity 31a and 31b of the case 8. The end caps 20 and 22 are mounted on the case 8 by end cap supports 32 and 34 which are fixed into a respective extremity 31a and 31b of the case 8 and the end caps 20 and 22.

In some instances the energy levels to be provided by the composite charge may not require a propellant charge to be contained within the carrier 4 in which case the propellant charge may be omitted.

The end cap 20 locates an igniter charge 36 against a perforated combustible end disc 38 adjacent the propellant charge rods 16. The top 28 of the end cap 20 has a central hole to provide access to the igniter charge 36 by a primer tube (not shown). The igniter charge 36 may be omitted from the end cap for separate loading into the gun barrel if desired.

The incremental charges 6 each comprises a combustible charge *case 40 of a kraft based material having a cylindrical form of 15 generally oblate hemispherical cross section with a rectangular side 42 and a curved side 44, the case 40 containing a bundle 46 of propellant charge rods 47 held together by combustible ties positioned towards each end of the bundle 46. The incremental charges are maintained adjacent the case 8 by 'the end caps and 22 within a cylindrical envelope 47 defined by the end caps and 22.

Alternative engagement means to that provided by the end caps and 22 shown can be provided to maintain the incremental charge cases 40 in position relative to the case 8. For example, a releasable fastening fitted to the respective cases 40 and 8 such as a interlocking hook and fibrous pads.

Each tubular side wall 24 and 26 of the end caps 20 and 22 have inner surfaces 23 scored by channels 48 and 49 respectively, which weaken sectors of the end caps 24 and 26 to allow each incremental charge 6 to be removed. The portion of the end cap 24 and 26 locating an incremental charge 6 breaks off or is folded out of the way on application of a radial force. The remainder of the end caps 24 and 26 stay intact to locate the remaining incremental charges adjacent the basic charge.

Other methods of weakening the end caps 24 and 26 to allow release of the incremental charges 6 can be readily devised. For example the tubular side walls 24 and 26 may be provided with a saw-tooth edge which engages with the incremental charges 6, the teeth being readily broken or folded back. Preferably the end caps 24 and 26 are castellated as shown in Figure 9, the strength of the engagement between the end caps 24 and 26 and the incremental charge cases 40 being determined in part by their mark- ratio.

Each incremental charge 6 can be split from the case 8 independently of the others allowing four distinct explosive energy configurations. The incremental charges can be removed manually by pulling them away from the carrier 4 or by use of automatic means as will be described below with reference to Figures 3 to 6.

Referring now to Figure 7 there is shown a composite charge largely as shown in Figure 1 but having a different form of igniter in the end cap 28. The end cap 28 contains an igniter charge held against cloth closures 62 and 64. The igniter charge is initiated in known manner by means of a gun powder pad 66.

S Referring now to Figure 8 there is shown a composite explosive charge largely as shown in Figure 7 but in which the case 8 has castellations 68 formed at the corners of the triangular case 8 which castellations 68 extend through slots (not shown) in a kraft base plate 70. The plate 70 fixes the end cap 28 to the case 8.

The castleattions 68 meet the cloth closure 64 on the underside of the discoid end portion 28 to support the portion 28 against inward flexure. The igniter charge is not shown for clarity.

Referring to Figure 9 there is shown schematically a cross section of an alternative form of case 8 and 40 in which the corners of the cases 8 and 40 have larger radii of curvature than those of the embodiments of Figures 1 to 8. This reduces the surface areas of the cases 8 and 40 for a given propellant charge volume as well as allowing a more even thickness of case, in particular the tendency to have a- greater thickness of material at the corners is reduced. This provides a 20-25% weight reduction for a given strength of case and volume of propellant.

Referring to Figures 3 to 6 there is shown a composite propellant charge 2 that has been brought to a preparation section of an automatic charge handling apparatus in which the tops 28 and of the end cap 20 and 22 (not shown) are engaged by rotatable drive discs (not shown) which exert an inward force on the composite charge 2. Ridges in the drive disc (not shown) engage in radial grooves 39 formed in the end caps 20 and 24 (see Figure 10). A planar stripper pawl 52 rotatable about a hinge axis A is biased to urge the edge of the pawl into contact with the outer surface of the charge 2. The charge 2 is rotatable by the drive discs in the direction opposing the lay of the pawl 52, that is in an anticlockwise direction as drawn. A sensor (not shown) associated with the stripper pawl 52 detects when the end of the pawl moves inwardly into the gap between two of the incremental charges 6 as shown in Figure 4. The charge 2 is then rotated through a further 120 to o..:strip one whole incremental charge 6 from the carrier 4 as shown in O 0 Figures 4 to 6. The stripped charge falls from the composite charge 2 into a disposal bin (not shown). Once the required number of incremental charges 6 have been subtracted the drive discs are 0* separated and composite charge 2 moved to the loading mechanism of S. the automatic charge handling apparatus. Referring now to Figure 9 there is shown an embodiment of the invention having an end cap in which the discoid portion 72 is provided with three integrally moulded, raised triangular portions 74. These act as stops to limit the lateral movement of the incremental charges 40 while being stripped by the method shown in Figures 3 to 6 so obviating any tendency for the charge 40 to jamm against a neighbouring incremental charge and to act as a fulcrum to aid the stripping action of the pawl 42.

The fixed length of the composite charge according to the present invention means that simplified ramming mechanisms for shell and charge can be used; the shell can be partly rammed into place and then the shell and charge ram together into the fully loaded position using a common ramming mechanism of single length ramming stroke regardless of the total charge energy. The fixed length of the composite charge also ensures that the igniter is always near the primer tube and that shell fall-back is reduced to a known, acceptable limit. Charge preparation is also simplified since only complete composite charges need to be carried, the stripped incremental charges being retained in a disposal bin after removal.

It will be clear to those skilled in the art that different embodiments of the present invention, incorporating geometrical and structural configurations other than those shown in the specific examples above are possible.

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a S 0* a a a* ct a a TILE ABSTRACT IS ON THE

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Claims (6)

1. A composite propellant charge for launching a projectile from a gun barrel comprising an elongate, rigid carrier having a first and a second longitudinal carrier extremity -and -at least one elongate incremental charge removably located adjacent the carrier each incremental charge being substantially parallel to the carrier and extending no further than the first and second carrier extremity.

2. A composite propellant charge as claimed in claim 1 in which the carrier comprises an elongate, rigid support having a first and a second longitudinal support extremity and a first and a second end member mounted on each of said support extremities, so as to define a cylindrical envelope; each of the incremental charges being located on the carrier so as to not extend outside the envelope.

3. A composite proplellant charge as claimed in claim 2 in which the first and second end members and each incremental charge are releasably interengageable. A composite propellant charge as claimed in claim 3 in which the first and second end members each comprises an end cap having a "discoid portion defining one of the carrier extremities and a tubular portion extending from the discoid portion, the tubular portion releasably engaging each incremental charge. A composite propellant charge as claimed in claim 4 in which the tubular portion of the end cap is castellated.

6. A composite propellant charge as claimed in any one of claims 2 to 5 in which the support supports the discoid portion against inward flexure.

7. A composite propellant charge as claimed in any one of the preceding claims in which the carrier contains a propellant charge.

8. A composite charge as claimed in any one of claims 2 to 7 in which each of the end members has a projecting member located between adjacent incremental charges. Dated this 5th day of June 19.9.2 ROYAL ORDNANCE PLC By their Patent Attorneys DAVIES COLLISON CAVE