Patent Publication Number: US-8522683-B2

Title: Method for producing a shell and a shell with a sabot projectile produced by this method

Description:
The present application claims priority from U.S. Provisional Patent Application No. 61/199,808 filed Nov. 20, 2008, the entire contents of which are incorporated by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     The invention concerns a method for producing a shell with a projectile, a combustible propellant charge casing, and a casing cover that joins the propellant charge casing with the projectile. The projectile has a sealing ring adjacent to the casing cover. The invention also concerns a shell that has a sabot projectile. 
     Especially in the case of large-caliber tank ammunition with a combustible propellant charge casing, the propellant charge casing is usually connected to the projectile by means of a casing cover, which can consist of a combustible material (for example, nitrated, resin-impregnated cardboard) or an inert material (for example, nonnitrated resin-impregnated cardboard). In addition, tank ammunition requires a deformable sealing ring to prevent propellant gases from flowing past the projectile during its passage through the gun barrel. 
     One of the disadvantages of the previously known methods is that the assembly of the shells is relatively time-consuming and expensive, because separate production lines are necessary for the mounting of the casing cover and the mounting of the sealing ring. For example, the casing cover is joined with the rear region of the projectile body by a bolted joint or an adhesive joint, while the separate sealing ring, which is made of metal or plastic, is either pressed or injected into an annular groove provided for it in the projectile and then must be aftertreated. 
     SUMMARY OF THE INVENTION 
     The object of the invention is to provide a method of the aforementioned type that allows more cost-effective assembly than comparable prior-art methods for producing shells with a casing cover. Another object of the invention is to provide a shell with a sabot projectile that is produced by this method. 
     The invention is based essentially on the idea of producing the casing cover as an injection molded part made of an elastic plastic, such that the front end region of the casing cover facing the projectile forms the sealing ring of the projectile. 
     The integration of the sealing ring in the casing cover allows simple assembly of the shell. In addition, the replacement of the relatively brittle and abrasion-sensitive material used for the casing cover in previously known shells by an elastic plastic means that the total assembly consisting of the casing cover, projectile, and propellant charge casing is less susceptible to fracture and cracking than similar, previously known assemblies, since the elastic plastic absorbs deformational energy. Furthermore, with a plastic easing cover, unintended ignition of the casing cover does not occur if the casing cover rubs against parts of the gun during loading and unloading. In addition, the protective coating needed with previously known casing covers can usually be dispensed with here. 
     The casing cover is preferably provided with an annular rated break point between the region serving as the sealing ring and the region adjacent to it towards the rear end, so that upon discharge, the casing cover separates along the rated break points as the projectile passes into the bore of the gun barrel. The remnants of the casing cover remaining in the area of the loading chamber of the gun barrel are then expelled from the muzzle end of the barrel by the propellant charge gases. 
     The area of the casing cover that serves as the sealing ring can be pressed or shrunk onto the projectile or can be fastened to the projectile by adhesive bonding. 
     It can also be provided for the area of the casing cover that serves as the sealing ring to be fastened to the projectile by a locknut. 
     Further details and advantages of the invention are apparent from the following specific examples, which are illustrated by the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a longitudinal section through the projectile end of a shell of the invention with a sabot projectile and a casing cover. 
         FIG. 2  is an enlarged view of the casing cover shown in  FIG. 1 . 
         FIG. 3  is a perspective view of the casing cover shown in  FIG. 2 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  shows a shell  1  to be fired from a large-caliber smooth-bore cannon. It comprises a sabot projectile  2 , a propellant charge casing  3 , which is merely indicated by broken lines, and a casing cover  4 , which joins the propellant charge casing  3  and the sabot projectile  2 . The sabot projectile  2  consists basically of a subcaliber penetrator  5  and a discarding sabot  6 . In the illustrated embodiment, the sabot  6  is a cup sabot with a plate-shaped propulsion element  7  acting from the rear end on the subcaliber penetrator  5 . 
     In accordance with the invention, the casing cover  4  is an injection molded part made of an elastic plastic, whose front end region  8  ( FIG. 2 ) encloses the propulsion element  7  of the sabot  6  and forms the sealing ring of the sabot projectile  2 . 
     To ensure definite separation of the sabot projectile  2  from the propellant charge casing  3  during discharge, an annular rated break point  10  is provided between the front end region  8  of the sealing ring and the adjacent rear end region  9 . This rated break point  10  is preferably arranged in such a way that when the shell  1  is loaded in a cannon, the rated break point  10  is located in the area of the conical transition to the loading chamber of the cannon, so that when the cannon is fired, the casing cover  4  separates along the rated break points  10  as the sabot projectile  2  passes into the bore of the gun barrel. The remnants of the casing cover  4  remaining in the area of the loading chamber of the gun barrel are then expelled from the muzzle end of the barrel by the propellant charge gases. 
     In the embodiment illustrated in  FIG. 1 , the casing cover  4  is fastened on the sabot projectile  2  by a locknut  11  screwed onto the rear end of the plate-shaped propulsion element  7 . 
     Naturally, the invention is not limited to the specific embodiment described above. For example, the shell is not necessarily one which has a tailpiece-stabilized sabot projectile, but rather the method of the invention can also be used, for example, for shells with a tailpiece-stabilized equal-caliber projectile body. In this case, the region of the casing cover that serves as the sealing ring can be fastened to the usually conically constructed region of the tailpiece holder that faces the projectile body.