Abstract:
An adaptation cartridge comprises a firing pin casing which is screwed into a cartridge chamber or cartridge chamber tube and is secured against rotation by a radially displaceable slide. The cartridge is used for training on a gun having a subcaliber barrel adapter.

Description:
FIELD AND BACKGROUND OF THE INVENTION 
     The present invention relates in general to cartridges for guns, and in particular to a new and useful adaptation cartridge for an adapter barrel system for the firing of subcaliber ammunition from a gun barrel of larger caliber, with a centrally inserted cartridge chamber and a firing pin casing axially following the chamber. 
     An adaptation cartridge which, as to form and weight, corresponds to an original cartridge of live ammunition is used for training purposes, and is received centrally in a cartridge chamber for a subcaliber ammunition. The firing pin casing of such cartridges serves as transmission element for detonating the cartridge and at the same time as a supporting element for absorption of gas pressure generated in the gun. This means that the firing pin casing takes support on the end side on the breech mechanism of the weapon, e.g. an armor-piercing gun. When closing the breech mechanism, the axially displaceable firing pin casing is pushed forward to the cartridge chamber and thus unlocks the firing pin centrally inserted in the casing. Since after firing a residual stress remains in the adapter barrel system, the firing pin casing is pressed axially against the breech mechanism with great force due to the expansion of the cartridge. The disadvantage of this is that for opening the breech to remove the empty cartridge case, much force must be exerted, and this in turn leads to ejection problems. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention therefore, to provide an adaptation cartridge of the above-mentioned kind which ensures satisfactory and realistic functioning with proper ejection of the adaptation cartridge and adequate safety. 
     According to the invention, this problem is solved in that the firing pin casing is inserted centrally into the cartridge chamber and is connected mechanically and/or dynamically with the cartridge chamber on the breech side and further comprises means for safety against axial and radial displacement as well as of the firing pin. In a technically equivalent design, the firing pin casing may be inserted centrally in a cartridge chamber tube and be mechanically and/or dynamically connected to the cartridge chamber tube, which by its front end is firmly connected to the cartridge chamber and takes support on the adaptation cartridge axially on the breech side. The advantage of an adaptation cartridge for adapter barrel systems designed in this original manner is that it is well suitable for training purposes and is laid out so that all forces occurring during firing are absorbed within the adaptation cartridge. While in the described state of the art cartridges, the breech mechanism jams badly due to the bracing of the ammunition on the breech and can be opened only with great force, with the cartridge according to the invention no clamping whatever occurs. Cartridge ejection can take place easily and no disturbance occur. For the operator this means great safety combined with easy handling. In addition, the invention makes possible a training bombardment in the required time. 
     In a variant of the invention, the firing pin casing may be connected to the cartridge chamber or cartridge chamber tube on the breech side by a trapezoidal thread. Besides safety, this makes it especially easy to load the adaptation cartridge with the subcaliber ammunition. Advantageously the trapezoidal thread is designed so that it is self-locking during bombardment, but is easy to unscrew for disassembly. 
     As a further variant, the breech-side end wall of the firing pin casing may have provided in at least one off-center bore in which is inserted an axially displaceable joint which is in operative connection with a slide radially displaceable in a safety slit in the cartridge chamber or cartridge chamber tube, which slide is held in safe position by a spring. 
     The joint can embrace a cross-bolt, which is passed through a cross-slot in the slide, the slot slanting outward from the plane of the longitudinal axis of the blind bore. 
     Further a second off-center blind bore may be provided in the breech side end wall of the firing pin casing, in which bore an axially displaceable joint is inserted which is in operative connection with a slide radially displaceable in a recess in the firing pin, which slide is held in safe position by a spring. 
     These aforesaid features relate to advantageous designs for safety against radial and axial displacement of the firing pin casing and of the firing pin. The safety device engages whenever the striking pin casing is inserted into the adaptation cartridge. Release of the safety device is possible only with a tool to be introduced into the blind bore from the outside, in that the joint is displaced axially inward, thereby retracting the slide radially from the safety slit. 
     Accordingly, a further object of the invention is to provide an adaptation cartridge for an adaptor barrel system for firing subcaliber ammunition through a gun barrel of larger caliber, comprising a cartridge chamber for carrying the subcaliber ammunition, a firing pin casing centrally inserted in the cartridge chamber and connected to the cartridge chamber and means near the breech end of the adaptation cartridge for axially and radially fixing the firing pin case with respect to the cartridge chamber. 
     A further object of the present invention is to provide such an adaptation cartridge wherein the safety means comprises at least one off center blind bore in the firing pin casing, a joint movably mounted in the blind bore and a slide movable radially with axial movement of the joint for engaging and disengaging a locking safety slot to prevent relative rotation between the casing and the cartridge chamber. 
     A still further object of the invention is to provide an adaptation cartridge which is simple in design, rugged in construction and economical to manufacture. 
     The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which a preferred embodiment of the invention is illustrated. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     An example of the invention is illustrated in the drawings, wherein: 
     FIG. 1 is a longitudinal sectional view of the adaptation cartridge; 
     FIG. 2 is a sectional view of the anti-displacement and anti-rotation device of the striking pin casing of the invention, taken along line II--II of FIG. 1; 
     FIG. 3 is a sectional view of a safety device taken along ling III--III of FIG. 2; and 
     FIG. 4 is a sectional view of the striking pin lock taken along line IV--IV of FIG. 1. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The inventive adaptation cartridge 1 consists essentially of a tubular jacket 2, a cartridge chamber 3, a cartridge chamber tube 4, and a firing pin casing 5. 
     The cartridge chamber 3 is arranged to be centered in jacket 2 of the adaptation cartridge, with the cartridge chamber tube 4 following the cartridge chamber 3 toward the breech mechanism 6 of a gun (not shown) in coaxial arrangement. Tube 4 may be on a one piece extension of the cartridge chamber 3. In the example shown in FIG. 1 it is a separate part, connected to the cartridge chamber 3 mechanically and dynamically, e.g. by threading, welding or pressing. The cartridge chamber tube 4 takes support axially at the breech side end on a flanged ring 7 of the adaptation cartridge 1. The firing pin case 5 has a central bore 8, in which a firing pin 9 and firing pin spring 10 are inserted in an intermediate sleeve 11. At the breech side end, bore 8 has a thread bore 12 to which a tool can be screwed. The thread serves at the same time to receive an assembling tool, as will be described later. In the rear end wall 13 of the firing pin casing 5 an off-center blind bore 14 is cut (FIG. 2). Inserted in the blind bore is a fork-like joint 15, whose arms embrace a cross-bolt 16. Bolt 16 is fitted in a cross-bore 17 in a slide 18 which is radially displaceable and engages in a safety slit 19 of the firing pin casing 5. The cross-bore 17 in slide 18 starts from the plane of the longitudinal axis of the blind bore 14 and slants radially outward. A spring 20 which is supported on the end of the blind bore 14, bears against the slide 18. The protection of the firing pin casing 5 against rotating thus occurs through slide 18 engaging into the safety slit 19 of the cartridge chamber tube 4. 
     Casing 5 is threaded into tube 4 and the tightening of casing 5 into cartridge chamber tube 4 is done by a tool (not shown) which is screwed into the firing pin bore 12 and which protrudes into the blind bore 14 by a tenon. The screwing in of the tool causes axial penetration of the tool tenon into the blind bore 14 against the joint 15. Joint 15 pushes bolt 16 forwardly and thereby the slide 18 moves radially inwardly due to the action of bolt 16 in bore 17. Slide 18 thus is pulled inwardly out of slit 19 while the firing pin casing 5 is being screwed into the cartridge chamber tube 4. In the end position and when the tool tenon is removed, bolt 16 moves back in the cross-bore 17 and thereby causes the slide 18 to come out radially into the safety slit 19 due to the force of spring 20. 
     The slide 18 is now held in this safe position by the joint 15 as well as the spring 20. Unlocking of case 5 can again occur only with the tool, by which the tenon is pushed into the blind bore 14 against the joint 15 and the latter is displaced axially. Thereby the bolt 16 is moved in the control slot or bore 17 and the slide 18 is retracted out of the safety slit 19 radially. 
     Locking of the firing pin 9 occurs in a similar manner. Here the unlocking is done by way of a locking rod 21 in a second off center blind bore 22 in the firing pin casing 5. The locking rod 21 presses axially against a fork-like joint 23, which in turn extracts a slide 26 radially from a recess in the firing pin 9 by way of a bolt 24 in an oblique slot 25. Slide 26 is again held in safe position in the blind bore 22 by a compression spring 27. A subcaliber cartridge 28 is shown in the cartridge chamber 3. 
     In operation, the adapatation cartridge 1 is seated in the large caliber gun with the adapted barrel which is adapted to the diameter of the projectile of cartridge 28. Loading rod 21 has a projection shown in FIG. 1 which extends beyond the breech end face 13. With adaptation cartridge 1 seated in the gun, this projection forces rod 21 forwardly (toward cartridge 28) against the bias of spring 27. This moves slide 26 radially outwardly to permit the forward movement of firing pin 9. When firing the gun, the firing pin of the gun (not shown) can thus strike firing pin 9 which in turn fires cartridge 28. 
     While a specific embodiment of the invention has been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.