Abstract:
A projectile with a tandem charge consisting of a borehole charge and a secondary firing charge, in which exact piercing guidance between the borehole charge and the secondary firing charge is obtained by the counterdirectional motion of the housing part with the secondary firing charge relative to a tubular guiding part of the housing.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a projectile having a tandem charge consisting of a borehole charge or shaped charge and a secondary firing charge, which projectile comprises a tubular housing in which the secondary firing charge provided with a propellant charge is stored. 
     German Pat. No. 18 11 331 describes a projectile with a tandem charge in which the secondary firing charge is stored in a tubular shaft behind the shaped charge. The secondary firing charge has a propellant charge which is initiated by the bottom fuse of the projectile upon impact. Firing the shaped charge by the secondary firing charge is not provided in the device disclosed in that patent, however, 
     From DE-OS No. 27 57 806, a connecting device between two stages of an aerodynamic body with built-in propulsion drive has become known. The forward and the rear stage are arranged movably relative to each other by means of two meshing cylindrical surfaces and are held together by means of detachable fastening means. Because of the propulsion mechanism pressure of the rear stage, the fastening means are sheared off and the rear stage is pushed onto the forward stage. Guidance of the piercing bolt attached to the rear stage in the direction toward the percussion igniter fastened in the forward stage exists only in the region where the meshing cylindrical surfaces overlap. 
     In tandem charges, especially in take-off trajectory bombs of present design, it is known to equip the housing with a tubular guide, in which the secondary firing charge is supported with a sliding fit. Thus, the secondary firing charge will move in the guide toward the forward housing part in the event of a suitably directed acceleration force. This process is utilized for piercing a percussion fuse. However, operating failures occur again and again because no ignition could take place due to an axial offset of the piercing guide or premature breaking away of the borehole charge. 
     SUMMARY OF THE INVENTION 
     It is therefore the object of the present invention to provide a piercing guide in a tandem projectile such that malfunctioning of the ignition especially due to an offset of the piercing needle relative to the percussion fuse is prevented. 
     The above and other objects of the invention are achieved by a projectile with a tandem charge comprising a shaped charge and a secondary firing charge, the projectile comprising a tubular housing in which the secondary firing charge provided with a propellant charge is stored, the projectile comprising a first housing part which contains the shaped charge together with a percussion fuse arranged rearward and axially centered and which has at its rearward outer surface an outside surface with a defined guide length. The projectile further contains a second housing part with a straight or a stepped inside surface which is pushed with the forward part of the inside surface completely over the outside surface given by the guide length and is held by means of detachable fastening means and which has at its rearward end a housing bottom sealing the second housing part. The projectile contains the housing of the secondary firing charge with the igniting device belonging thereto and a propulsion reflector (cartridge-case base) which is supported with its outer surface in the inside surface of the second housing part with a sliding fit and which has as its tip a piercing bolt which is arranged axially centered and corresponds to the percussion fuse, and is fastened to the second housing part with further detachable fastening means. Finally, the projectile contains between the propulsion reflector and the housing bottom an expansion space and a gas generator which is arranged at the housing bottom and is initiated by means of an igniter started by the percussion contact. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     An embodiment according to the invention is shown in the sole figure of the drawing and will be described in greater detail in the following detailed description: 
     The FIGURE shows a longitudinal section through a tandem charge projectile. 
    
    
     DETAILED DESCRIPTION 
     The projectile basically comprises three housing parts 1, 2, 3 with the masses m1, m2, m3 which are supported movably inside each other in an at least partially form-locking manner. The forward first housing part 1 contains the shaped charge BL of the tandem projectile. Axially behind it, the corresponding pierce-sensitive igniter SZ is arranged. At its rearward end, the outer surface MF1 of the housing part 1 has a setback cylindrical outside surface AF with the length LF. 
     Onto this cylindrical outside surface AF, the forward end of the cup-shaped second housing part 2 is pushed with its cylindrical inside surface JF1 and fastened by means of a number of screws S 1  ..., Sn which can be sheared off. The housing part 2 can be designed as a stepped tube or advantageously with a sructured envelope SH, the structure envelope being fastened to the housing part 2 by means of screws S&#39; 1  . . . , S&#39; n , the shearing-off force of which is at least twice as large as that of the fastening means S 1  . . . , S n . In its rearward part, it has a further cylindrical inside surface JF2, in which the housing 3 of the secondary firing charge NL is movably supported with its cylindrical outside surface MF2. 
     The secondary firing charge NL is fastened in the region of its propulsion reflector T by means of shear pins ST 1  . . . ST n  to the gas generator G, leaving an expansion space E free. The gas generator itself is bolted with its form-locking housing to the housing body GB by mounting screws HS 1  . . . , HS n . 
     The third housing part 3 finally contains the secondary firing charge NL of the tandem projectile and the corresponding fuse ZNL. A piercing bolt AB is fastened, axially centered, to the tip of the third housing part; it is aligned accurately centered with the piercing-sensitive igniter SZ. 
     The piercing process proceeds as described in the following: 
     When the projectile G strikes a target Z, the inpact igniter AK mounted in the tip of the projectile, for instance, a proximity fuse of known design, triggers the gas generator G. The gas pressure generated by the same escapes suddenly into the expansion space E and acts on the mutually opposite end faces of the propulsion reflector T and the housing bottom GB with pressure. Thereby, the shear pins ST 1  . . . , ST n  and simultaneously the screws S 1  . . . , S n  are sheared off and the oppositely-directed motion process from the second housing part 2 and the secondary firing charge NL begins. 
     The second housing part 2 is guided on the cylindrical outside surface AF of the first housing part and itself guides the third housing part 3 along the second cylindrical inside surface JF2. The length LF of the piercing guide necessary for operation through the second housing part 2 to the housing part 1 equipped with the impact fuse is calculated, depending on the piercing travel AW required for operation as a function of the housing masses m2 and m3 of the second and third housing part 2, 3 and an arbitrarily selectable safety factor S as: 
     
         LF=(m3/m2)×AW×S. 
    
     By the masses which are moving freely relative to each other, an axially centered guidance is assured at any time during the piercing process. 
     The special advantage of the invention is seen in the fact that with such a design of a tandem charge, exact piercing guidance is always assured due to the counter-moving mass motion, independently of the conditions under which a target is struck. 
     In the foregoing specification, the invention has been described with reference to an exemplary embodiment thereof. It will, however, be evident that various modifications and changes may be made thereunto without departing from the broader spirit and scope of the invention as set forth in the appended claims. The specification and drawings are, accordingly, to be regarded in an illustrative rather than in a restrictive sense.