CARTRIDGE WITH SAFETY FUSE IN THE DRIVE SYSTEM, AND METHOD FOR PRODUCING IT

Abstract

A cartridge with a drive system and a projectile which is connected to the drive system, wherein the drive system has a propellant case filled with a propellant and has a case bottom containing a substantially axially extending case bottom opening with a T-shaped edge contour. The case bottom opening is closed by a plug which is of T-shaped configuration, receives an ignition cap and is held in position by a safety fuse ring of a rupture disc. The safety fuse ring is arranged between the front side of the head part of the plug and the rear side of an adjoining inner-side projection of the case bottom, with the result that the propellant chamber is delimited by the front surface of the plug neck. An inner edge of the safety fuse ring engages in a positively locking and/or non-positive manner into an outer groove-shaped recess of the plug.

Claims

1. A method for assembling a cartridge having a propulsion system and having a projectile connected to the propulsion system, wherein the propulsion system comprises a propellant casing that is filled with propellant charge and has a case bottom that has a substantially axially extending case bottom opening, and wherein the case bottom opening is closed by a plug that accommodates a primer and is held in this position by a fusible ring of a burst protection device, the method comprising: inserting the fusible ring into the case bottom opening from a rear side of the case bottom of the propellant casing until a front of the ring bears against an internal projection of the case bottom, and then inserting the plug into the case bottom opening; and exerting an axial force on a back of the fusible ring by a head part so that the fusible ring is compressed and plastically deformed and its material flows radially into the groove-shaped recesses of the plug and the case bottom as a result of which no additional seals are necessary.

2. The method according to claim 1, wherein the primer is joined to the plug before the plug is inserted into the case bottom opening of the propellant casing.

3. The method according to claim 1, wherein a filling of the propellant casing takes place through the case bottom opening.

4. A cartridge assembled according to the method of claim 1, wherein the front of the fusible ring bears against the back of an internal projection of the case bottom and the back of the ring bears against the front of the head part of the plug, wherein the inner edge of the ring engages an outer groove-shaped recess of the plug in a positive and/or frictional manner and its outer edge engages an inner groove-shaped recess of the case bottom in a positive and/or frictional manner, so that the fusible ring is not directly subjected to gas pressure and no additional seals are required.

5. The cartridge according to claim 4, wherein the fusible ring has an outside diameter chosen such that it is insertable into the case bottom opening from the back of the case bottom for assembly of the cartridge.

6. The cartridge according to claim 4, wherein the plug is T-shaped in design.

7. The cartridge according to claim 4, wherein the plastically deformable fusible ring material is an alloy made of bismuth and tin.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus, are not limitive of the present invention, and wherein:

[0020] FIG. 1 illustrates a longitudinal section through the rear area of the propulsion system of a cartridge according to the invention after insertion of a fusible ring and a plug into the case bottom opening of the propellant casing, before the plug is in its assembled final position, and

[0021] FIG. 2 illustrates a view corresponding to FIG. 1 after the plug has reached its final position.

DETAILED DESCRIPTION

[0022] In FIGS. 1 and 2, the propulsion system of a cartridge according to the invention (for example, a practice cartridge of 40 mm caliber) is labeled 1. For the purpose of a complete insensitive munition (IM), reference is made to DE 10 2004 020 838 B3 or DE 10 2011 014 402 A1, which are incorporated herewith by reference.

[0023] The propulsion system 1 comprises a propellant casing 3 filled with a propellant charge 2 and having a case bottom 4 arranged at the back. The case bottom 4 has a case bottom opening 5 with a (preferably) T-shaped edge contour viewed in the direction of the longitudinal axis of the cartridge. The case bottom opening 5 is closed by a corresponding plug 6 that here is T-shaped in design with a head part 7 and a plug neck 8. A primer 9 is pressed into this plug 6.

[0024] Arranged between the front 10 of the head part 7 of the plug 6 and the back 11 of an internal projection 12 of the case bottom 4 is a plastically deformable fusible ring 13 (made from an alloy of bismuth and tin, for example) that has an outside diameter chosen such that it can be inserted into the case bottom opening 5 from the back 14 of the case bottom 4 (FIG. 1).

[0025] Starting from the position of the plug 6 shown in FIG. 1, if the head part 7 is now subjected to an axial force in the direction of the fusible ring 13, the front 17 of the fusible ring 13 bears against the back 11 of the internal projection 12, and the back 18 of the fusible ring 13 bears against the front 10 of the head part 7 of the plug 6, so that the fusible ring 13 is compressed and plastically deformed. As a result, the material of the fusible ring 13 flows radially into a groove-shaped recess 15 of the plug 6 and into a groove-shaped recess 16 of the fusible ring 13 [sic: should probably read: “case bottom 4”] (FIG. 2). Consequently, the inner edge 19 of the fusible ring 13 now engages the outer groove-shaped recess 15 of the plug (6) in a positive and frictional manner, and the outer edge 20 of the fusible ring engages the inner groove-shaped recess 16 of the case bottom 4 in a positive and frictional manner.

[0026] As a result, the plug 6 is fixed in place within the case bottom opening 5 without appreciable impingement on the fusible ring 13 by the propellant gases occurring in the event of later firing.

[0027] In contrast, if the cartridge should be exposed to an unintentional fire, for example in a munitions depot, the fusible ring 13 melts before ignition of the primer 9 or the propellant powder takes place, and the plug 6 is released, so that after ignition of the propellant charge 2 the propellant gases that form push it out of the case bottom opening 5 without appreciable velocity.

[0028] Assembly of the propulsion system 1 itself is simplified. The primer 9 is placed in the plug 6. The fusible ring 13 is placed in the propellant casing 3. The unit comprising the plug 6 and primer 9 is then pressed into the propellant casing 3 with axial force. In consequence, as already mentioned, the fusible ring 13 is compressed in height so that the material deforms plastically and flows radially into the groove-shaped recesses 15 in the propellant casing 3 and plug 6. This pressing also provides sealing against external environmental influences. The deformation of the fusible ring 13 creates a secure retaining force against the forces arising during transport, vibration, and firing.

[0029] The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are to be included within the scope of the following claims.