Abstract:
A method seals a projectile having a wall against propellant charge gas pressure occurring during firing of the projectile. A propellant charge is ignited and the projectile is acted upon from the outside by the propellant charge gas pressure. In order reliably to seal the projectile, during the firing thereof, against penetration by propellant charge gas from the outside into the interior thereof, it is proposed that a contact connection of an electrical interface arranged in a channel in the wall is moved in the channel by the propellant charge gas pressure and presses a seal into a sealing seat.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the priority, under 35 U.S.C. §119, of German application DE 10 2013 010 256.1, filed Jun. 18, 2013; the prior application is herewith incorporated by reference in its entirety. 
       BACKGROUND OF THE INVENTION 
     Field of the Invention 
       [0002]    The invention relates to a method for sealing a projectile having a wall against propellant charge gas pressure occurring during firing of the projectile, wherein a propellant charge is ignited and the projectile is acted upon from the outside with the propellant charge gas pressure. 
         [0003]    Modern, large-caliber ammunition is frequently equipped with a projectile which has control elements, control electronics and optionally a seeker head with an optical sensor. By an electronic homing system, it is possible for a shooter to record an image of a target object and to transmit the associated image data via a data line to the control electronics of the projectile before the projectile is fired. For this purpose, control data have to be transferred from the shooter&#39;s homing system to the control electronics of the projectile. 
         [0004]    Since the control electronics are located in the interior of the projectile, whereas the shooter&#39;s homing system is located outside the projectile, an electrical interface permitting an electrical connection between the control electronics and the homing system through a wall of the projectile is required. The electrical interface is expediently located in a channel in the wall of the projectile. 
         [0005]    During firing of the projectile, hot propellant charge gas with a gas pressure of several 1000 bar, with which the projectile is acted upon from the outside and is accelerated in the barrel or tube, arises. Penetration of the hot propellant charge gas into the interior of the projectile results in the control electronics located therein being damaged, and therefore flight control of the projectile by the control electronics may thereby be rendered inoperative. The electrical interface therefore has to be sealed so as to be tight in respect of the propellant charge gas pressure. 
         [0006]    Such an electrical interface is known from German patent DE 10 2005 029 325 B4, corresponding to U.S. Pat. No. 7,491,099. The electrical interface is sealed by a metal pressed body which is pressed into the wall so as to be tight in respect of the propellant charge gas pressure, and in which a metal contact pin is arranged. An electrical insulating layer which electrically insulates the wall from the pressed body is applied to the wall or to the pressed body. In order to seal against extreme propellant charge gas pressures which arise during firing of the projectile, the pressed body has to be firmly pressed in and has to sit very tightly and the insulating layer has to be thin. 
       SUMMARY OF THE INVENTION 
       [0007]    It is an object of the present invention to specify a method with which a projectile can be reliably sealed against penetration of propellant charge gas from the outside into the interior thereof. 
         [0008]    This object is achieved by a method of the type referred to at the beginning, in which, according to the invention, a pressure unit of an electrical interface arranged in a channel in the wall is moved in the channel by the propellant charge gas pressure and presses a seal into a sealing seat. 
         [0009]    The invention is based on the consideration that an electrical insulating layer which, in the prior art, is located on a wall or on a pressed body may be damaged if the pressed body tilts during assembly when being pressed into the wall. Damage to the electrical insulating layer may render the electrical interface unusable if electrical contact between the wall and the contact connection arises because of the damage. 
         [0010]    An insulating layer which is easy to damage can be omitted if an electrically insulating pressed body is used. However, the latter has to be highly stable because of the extreme propellant charge gas pressures and temperatures during firing of the projectile, and therefore only ceramic or glass are suitable as materials. However, tests have shown that a pressed body made of glass or ceramic may crack during firing because of the extreme propellant charge gas pressures of modern projectiles, thus impairing the tightness of the electrical interface. 
         [0011]    The invention solves these problems by the pressure unit being arranged movably in the channel. As a result, the pressure unit can press the seal into the sealing seat by the propellant charge gas pressure. The propellant charge gas pressure is therefore used for sealing the channel itself. This gives rise to the advantage that the channel does not have to be so tightly sealed before the firing. A pressed body can be omitted. Instead, the interface can be inserted considerably more loosely into the channel during assembly. This significantly reduces the risk of damage to electrical insulation. 
         [0012]    The channel is a passage in the wall of the projectile, which, together with a contact connection, produces an electrical contact through the wall. In a preferred manner, the channel is cylindrically symmetric. The axis of symmetry of the channel should be understood here as the axis of the channel. 
         [0013]    A contact connection is an electrical connecting element which is provided in order to produce an electrical connection between control electronics located in the projectile and an electrical system arranged outside the projectile. The contact connection can have a plug-in connection for the plugging in of a plug. 
         [0014]    The channel can have a tapered portion on which the seal can be supported in particular in a flat manner. The sealing seat can be formed by such a supporting surface. Further configurations of the channel can have a plurality of tapered portions and a plurality of sealing seats which can each comprise a supporting surface formed by the tapered portion thereof. 
         [0015]    A displacement of the pressure unit relative to the wall is interpreted as the movement of the pressure unit under the action of propellant charge gas pressure. The movement advantageously takes place parallel to the axis of the channel. In a preferred manner, the movement comprises a distance of at least 0.05 mm, in particular at least 0.1 mm. 
         [0016]    In an advantageous embodiment of the invention, the pressure unit is a contact connection of the electrical interface. By this means, the interface can be of particularly compactly sized design. 
         [0017]    Furthermore, it is advantageous if, when the propellant charge gas pressure occurs, the pressure unit presses a sealing section, which is oriented perpendicular to the axis of the channel, parallel to the axis of the channel into the sealing seat. A particularly large pressure on the sealing seat and therefore good sealing can thereby be achieved. In general, the seal can have one or more sealing sections, wherein a sealing section can be oriented perpendicular, parallel or obliquely to the axis of the channel. 
         [0018]    Furthermore, it is advantageous if the seal has a sealing section oriented parallel to the axis of the channel. The sealing section expediently surrounds the pressure unit, in particular the contact connection, radially. During the movement of the pressure unit, the sealing section can be pressed into the channel, for example by a pressure element of the pressure unit, expediently such that the sealing section is pressed in radially between the pressure unit and the wall and therefore seals the channel against penetration by propellant charge gas. 
         [0019]    As already explained, the pressure unit or the contact connection can be inserted loosely in the channel such that damage to the seal during insertion thereof is avoided. However, the contact connection here should be held so firmly in the channel that it does not fall out of the channel even in the event of shaking movements of the projectile, for example during transport. In addition, it is advantageous if the interface is sealed by the contact connection and the seal so as to be weather tight. 
         [0020]    It is therefore advantageous if the pressure unit is inserted only in a roughly pressed manner with the seal into the channel. This permits the movement of the pressure unit in the channel when the propellant charge gas pressure occurs, the movement bringing about a particularly tight pressing of the seal into the sealing seat. On being pressed in by the pressure unit, the seal is advantageously pressed into the channel more strongly radially than during the rough pressing, and this brings about reliable sealing of the channel against penetration by propellant charge gas. 
         [0021]    The seal advantageously has a sealing section oriented perpendicularly and a sealing section oriented parallel to the axis of the channel. It is advantageous if the compressive force caused on a sealing section, which is oriented perpendicular to the axis of the channel, by the movement of the contact connection is greater, in particular is at least 30 times greater, than the frictional force, which is caused during the movement of the contact connection, along a sealing section oriented parallel to the axis of the channel. As a result, firm pressing in of the seal during the movement of the contact connection is made possible. The perpendicular sealing section is expediently arranged further on the inside than the parallel sealing section. 
         [0022]    In a further advantageous embodiment of the invention, when the propellant charge gas pressure occurs, the pressure unit presses in a first sealing section, in particular a sealing section which is arranged further on the inside and is oriented perpendicular to the axis of the channel, temporally before a second sealing section which, in particular, is a sealing section which is arranged further on the outside and is oriented parallel to the axis of the channel. 
         [0023]    Two sealing sections can be pressed in temporally one after the other if there is a gap between the pressure unit and a sealing section. The pressure element thus, for example, only exerts a pressure on a sealing section oriented parallel to the axis of the channel if a sealing section oriented perpendicular to the axis of the channel has been compressed sufficiently strongly beforehand. 
         [0024]    The invention also relates to ammunition having a propellant charge and a projectile. The projectile has a wall which separates an interior space of the projectile from an exterior space around the projectile, and an electrical interface which is provided with a seal and is arranged in a channel in the wall. 
         [0025]    Reliable sealing of the interior space of the projectile can be achieved if, according to the invention, a pressure unit is mounted in the channel so as to be movable relative to the wall in such a manner that said pressure unit, during the movement thereof caused by propellant charge gas pressure arising during firing of the projectile, presses the seal against the wall. The pressure unit is expediently a contact connection. The pressure unit or the contact connection can be surrounded by the seal. 
         [0026]    In an advantageous refinement of the invention, the seal has a cup shape. The pressure element is advantageously arranged in the cup of the seal. 
         [0027]    Furthermore, it is advantageous if the seal has a sealing section which is arranged further on the inside and is oriented perpendicular to the axis of the channel, and a sealing section which is arranged further on the outside and is oriented parallel to the axis of the channel. 
         [0028]    In order to produce the interface, the seal is advantageously first of all placed onto the pressure unit, in particular pressed onto the latter. Alternatively, the seal can be sprayed onto the pressure unit, for example by thermal spraying, and then the pressure unit and the seal are inserted into the channel. It is advantageous if the pressure unit is inserted in a roughly pressed manner with the seal into the wall of the projectile. The effect which can be achieved by this is that the pressure unit together with the seal remains securely arranged in the channel during transport of the projectile. In addition, sealing against moisture, for example during storage of the ammunition, can thereby be achieved. 
         [0029]    The arrangement of the pressure unit and the seal in the channel is expediently mounted movable such that, during firing of the projectile, a movement of the contact connection that is caused by the propellant charge gas pressure and in which the seal is pressed against the wall is possible. 
         [0030]    The seal advantageously has a plurality of sealing sections which, in a particularly advantageous refinement of the invention, have one dedicated contact surface with the wall per sealing section. This has the advantage that a better sealing effect can be achieved. The sealing sections can comprise a sealing section which is arranged further on the inside and is oriented perpendicular to the axis of the channel, and a sealing section which is arranged further on the outside and is oriented parallel to the axis of the channel. In an alternative advantageous refinement of the invention, the seal has a sealing section which is arranged further on the inside and is oriented parallel to the axis of the channel, and a sealing section on the outside, which sealing section is arranged further on the outside and is oriented perpendicular to the axis of the channel. 
         [0031]    At least one sealing section is expediently in the form of a hollow cylinder. On the inside of the wall of the projectile, said hollow cylinder can have a base with an, in particular, circular opening, through which a contact connection can be guided. In an expedient manner, the casing of the hollow cylinder forms a sealing section which is arranged further on the outside and is oriented parallel to the axis of the channel, and the base of the hollow cylinder can form a sealing section which is arranged further on the inside and is oriented perpendicular to the axis of the channel. 
         [0032]    A good sealing action of the seal in the channel can be achieved if a sealing section which is oriented parallel to the axis of the channel is pressed inward parallel to the axis during firing and, in the process, exerts a radial pressure on the wall. A radial pressure contributing to the sealing can be achieved if the height of the sealing section oriented parallel to the axis of the channel is at maximum 20 times, in particular at maximum 8 times, the thickness of the sealing section. A firm radial pressing in of the sealing section, which is oriented parallel to the axis of the channel, between the contact connection and the wall can take place. For as firm a radial compression as possible, it is furthermore advantageous if the thickness of the sealing section oriented parallel to the axis of the channel is at least 0.1 mm, in particular at least 0.3 mm. 
         [0033]    The pressure unit is advantageously provided with a thickened portion, the maximum thickness of which is expediently greater than the minimum thickness of a tapered portion of the channel, which tapered portion forms a sealing seat. 
         [0034]    In a further advantageous refinement of the invention, a sealing section oriented parallel to the axis of the channel radially surrounds a cylindrical thickened portion of the pressure unit. With regard to a good sealing action, the thickness of the sealing section oriented parallel to the axis of the channel is at least 10%, in particular at least 15%, of the thickness of the thickened portion. 
         [0035]    The tapered portion of the channel can be continuous or step-shaped. A step-shaped tapered portion is advantageous. The thickened portion can have, for example, a cylindrical shape or the shape of a conical section. The pressure unit preferably has a thickened portion with a shoulder by which a sealing section oriented perpendicular to the axis of the channel can be pressed against the sealing seat. 
         [0036]    In an advantageous refinement of the invention, the pressure unit has a pressure element. The pressure element can bring about a pressing in of a sealing section between the pressure unit and the wall during the movement of the pressure unit. In the case of a seal having a plurality of sealing sections, the sealing section which can be pressed in by the pressure element can be a sealing section which is arranged further on the outside. If the sealing section arranged further on the outside is oriented parallel to the axis of the channel, the sealing section can advantageously be pressed in radially by the pressure element between the contact connection and the wall. 
         [0037]    In an expedient manner, the pressure element is spaced apart radially from the wall by a gap, and therefore the pressure unit is electrically insulated from the wall. 
         [0038]    In addition, it is advantageous if the pressure unit has a pressure element which is spaced apart from the sealing section of the seal by a gap. The gap makes it possible for the sealing section to be pressed in before another sealing section such that a sealing action can be achieved in two part steps. The gap is expediently arranged between the pressure element and a sealing section which is arranged further on the outside and is oriented parallel to the axis of the channel. The sealing section can thereby be pressed in after a sealing section which is arranged further on the inside and in particular is oriented perpendicular to the axis of the channel. 
         [0039]    The seal preferably contains dielectric material. An additional electrical insulating layer on the seal or the wall of the projectile, the insulating layer insulating the pressure unit, and in particular the contact connection, electrically from the wall of the projectile, can be omitted. A seal composed of an electrically insulating plastic which may optionally be fiber-reinforced is particularly advantageous. 
         [0040]    Furthermore, the invention relates to ammunition having a propellant charge and a projectile having a wall and an electrical interface, which is arranged in a channel in the wall, with a contact connection and a seal which has a sealing section which is oriented parallel to the axis of the channel, surrounds the contact connection radially and seals the contact connection with respect to the wall. 
         [0041]    A reliable sealing of the interior space of the projectile can be achieved by the fact that, according to the invention, the contact connection has at least one pressure element which at least partially radially overlaps the sealing section oriented parallel to the axis of the channel. 
         [0042]    If the seal has a plurality of sealing sections, the sealing section which is oriented parallel can be arranged further on the outside or further on the inside in the channel. The seal is advantageously of cup-shape design, and in particular is in the form of a hollow cylinder. 
         [0043]    The contact connection should expediently be held loosely in the channel such that the contact connection can be pressed in when compressive forces resulting from propellant charge gas pressure arising during firing of the projectile act on the contact connection. This has the advantage that the seal, for its part, can be pressed in through the contact connection. 
         [0044]    The description provided up to now of advantageous refinements of the invention contains numerous features which are reproduced, partially combined into a plurality of features, in the individual dependent claims. However, these features can expediently also be considered individually and put together to form meaningful further combinations. In particular, these features can in each case be combined individually and in any suitable combination with the method according to the invention and the device according to the invention as per the independent claims. 
         [0045]    Other features which are considered as characteristic for the invention are set forth in the appended claims. 
         [0046]    Although the invention is illustrated and described herein as embodied in a method for sealing a projectile and ammunition containing the projectile, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims. 
         [0047]    The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings. 
         [0048]    BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
         [0049]      FIG. 1  is an illustration showing ammunition with a propellant charge and a projectile having control electronics and an electrical interface according to the invention; 
         [0050]      FIG. 2  is an illustration of an electrical interface from  FIG. 1 ; 
         [0051]      FIG. 3  is an illustration showing an alternative electrical interface; and 
         [0052]      FIG. 4  is an illustration showing a further electrical interface with a contact connection having a frustoconical section. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0053]    Referring now to the figures of the drawings in detail and first, particularly to  FIG. 1  thereof, there is shown ammunition  2  with a propellant charge  4  and a projectile  6  which is held on a rear wall of the ammunition  2  by a holding device  8 . The holding device  8  has a predetermined breaking point which releases the projectile  6  during firing such that the projectile  6  can be accelerated by the propellant charge  4  and can take off forwards. 
         [0054]    The projectile  6  has a wall  10  which separates an interior space of the projectile  6  from an exterior space around the projectile  6 . Control electronics  12  are located in the interior space of the projectile  6 . The projectile  6  is surrounded from the outside by the propellant charge  4 . 
         [0055]    An electrical interface  16  is arranged in a channel  14  in the wall  10  of the projectile  6 . A data line  18  connects the control electronics  12  located in the projectile  6  to an electrical system  20  arranged outside the ammunition  2 . 
         [0056]      FIG. 2  shows the electrical interface  16  in the wall  10  of a projectile  6  in an enlarged illustration. The electrical interface  16  is formed with a pressure unit  22  which, in the exemplary embodiments illustrated, is configured as a metal contact connection  22  and which bears the same reference number as the pressure unit  22 . However, it is also possible to design a pressure element independently of a contact connection and without an electrical line function. The channel  14  in the wall  10  is cylindrically symmetric and has a step-shaped tapered portion  26  which forms an inner part of a sealing seat  28 . 
         [0057]    The contact connection  22  reaches completely through the channel  14  and is surrounded by a seal  24 . The contact connection  22  has a pressure element  30  and a cylindrical thickened portion  32  with a shoulder  34 . The seal  24  is in the form of a hollow cylinder. The latter is oriented parallel to an axis  36  of the channel  14  and, on the inside of the wall  10 , has a base with a cylindrical opening through which the contact connection  22  is guided. The casing of the hollow cylinder forms a sealing section  38  which is arranged further on the outside and is oriented parallel to the axis  36  of the channel  14 . The base forms a sealing section  40  which is arranged further on the inside and is oriented perpendicular to the axis  36  of the channel  14 . 
         [0058]    The sealing section  38  which is oriented parallel to the axis  36  of the channel  14  radially surrounds the thickened portion  32  of the contact connection  22  and is located in a radial part of the sealing seat  28 . The sealing section  40  which is oriented perpendicular to the axis  36  of the channel  14  rests on the axial part of the sealing seat  28 . A gap  42  spaces the pressure element  30  apart from the sealing section  38  which is oriented parallel to the axis  36  of the channel  14 . A further gap  44  spaces the pressure element  30  of the contact connection  22  apart radially from the wall  10 . 
         [0059]    The thickened portion  32  of the contact connection  22  has a diameter of 3 mm. The channel  14  has a diameter of 4 mm. The sealing section  38  which is oriented parallel to the axis  36  of the channel  14  and the sealing section  40  which is oriented perpendicular to the axis  36  of the channel  14  have a thickness of 0.5 mm. The sealing section  38  which is oriented parallel to the axis  36  of the channel  14  has a height of 3 mm. 
         [0060]    To produce the interface  16 , the cup-shaped seal  24  is placed around the contact connection  22 , in particular is pressed on the thickened portion  32  of the contact connection, such that the seal  24  radially compresses the contact connection  22 . The contact connection  22  is subsequently inserted with the seal  24  into the channel  14 , specifically in such a manner that the contact connection  22  is not ejected from the channel  14  even in the event of strong shaking. The seal  24  seals the channel  14  so as to be tight with respect to rain, and therefore the interior components of the projectile  6  are protected against weathering effects. In the event of a pressure from the outside of above 100 bar, the contact connection, which is located relatively loosely in the channel  14 , is moved inwards such that the contact connection presses onto the inner sealing section  40 . 
         [0061]    During firing of the projectile  6 , the propellant charge  4  of the ammunition  2  is ignited. The propellant charge gas arising in the process presses from the outside against the projectile  6  with a gas pressure of approximately 6000 bar. The pressure causes the holding device  8  to break off and leads to acceleration of the projectile  6  along a barrel. The propellant charge gas pressure in particular also acts on the contact connection  22  of the electrical interface  16 . 
         [0062]    The movably mounted contact connection  22  first of all presses, with the shoulder  34  of the thickened portion  32  thereof, during the movement thereof caused by the propellant charge gas pressure, the sealing section  40 , which is oriented perpendicular to the axis  36  of the channel  14 , into the sealing seat  28 . A first sealing action is thereby achieved. Owing to the gap  42  between the pressure element  30  and the sealing section  38  oriented parallel to the axis  36  of the channel  14 , the contact connection  22  initially does not yet press against the sealing section  38  which is oriented parallel to the axis  36  of the channel  14 . By this means, the inner sealing section  40  is initially compressed with the greatest possible pressure, and therefore the sealing section seals cracks possibly arising in the channel  14  during firing. 
         [0063]    If the sealing section  40  which is oriented perpendicular to the axis  36  of the channel  14  is pressed in to such an extent that the pressure element  30  of the contact connection  22  touches the sealing section  38  which is oriented parallel to the axis  36  of the channel  14 , the pressure element  30  begins to exert a pressure on the sealing section  38 . The sealing section  38  is pressed inwards and therefore causes a radial compressive force against the contact connection  22  and the wall  10 . An additional sealing action is thereby achieved by the gap between the thickened portion  32  of the contact connection  22  and the channel wall then also being sealed by the radial pressure of the sealing section  38 . The channel  14  is reliably sealed and the control electronics  12  of the projectile  6  protected. 
         [0064]      FIG. 3  illustrates an alternative configuration of the electrical interface  16  in the wall  10  of a projectile  6 . The description below is essentially restricted to the differences with regard to the exemplary embodiment in  FIGS. 1 and 2 , to which reference is made with regard to features and functions remaining the same. Components remaining substantially the same are basically numbered with the same reference numbers and features which are not mentioned are adopted in the exemplary embodiments below without being described again. 
         [0065]    The channel  14  has a tapered portion  26  with two steps, of which one forms an axial sealing seat  46  located further on the outside and the other forms a radial sealing seat  48  located further on the inside. The seal  24  does not have a base on the inside of the wall  10  of the projectile  6 , but rather has, on the outer side of the wall  10  of the projectile  6 , a collar which protrudes radially over the casing of the hollow cylinder section of the seal  24  and inwardly has a circular opening through which the contact connection  22  is guided. 
         [0066]    The casing of the hollow cylinder again forms the sealing section  38  which is oriented parallel to the axis  36  of the channel  14 , but is arranged further on the inside of this exemplary embodiment. In this case, the cover forms the sealing section  40  which is oriented perpendicular to the axis  36  of the channel  14 , but is arranged further on the outside in this exemplary embodiment. The sealing section  40  which is oriented perpendicular to the axis  36  of the channel  14  rests on the sealing seat  46  which is arranged further on the outside. The pressure element  30  of the contact connection  22  rests on the sealing section  40  which is oriented perpendicular to the axis  36  of the channel  14 . 
         [0067]    Also in the case of the electrical interface  16  illustrated in  FIG. 3 , the contact connection  22 , during the movement thereof caused by the propellant charge gas pressure, initially presses in the sealing section  40  which is oriented perpendicular to the axis  36  of the channel  14 . This can be attributed, in the case of this electrical interface  16 , to a gap  50  which spaces the thickened portion  32  of the contact connection  22  and the sealing section  38 , which is oriented parallel to the axis  36  of the channel  14 , axially apart from the wall  10 . 
         [0068]    If the sealing section  40  which is oriented perpendicular to the axis  36  of the channel  14  is pressed into the sealing seat  46  arranged further on the outside to such an extent that the sealing section  38  which is oriented parallel to the axis  36  of the channel  14  touches the sealing seat  48  arranged further on the inside, the contact connection  22  begins to radially press in the sealing section  38 , which is oriented parallel to the axis  36  of the channel  14 , between the contact connection  22  and the wall  10 . 
         [0069]      FIG. 4  illustrates a further possible configuration of the electrical interface  16 , which is depicted in  FIG. 1 , in the wall  10  of a projectile  6 . The thickened portion  32  of the contact connection  22  has two sections: a cylindrical section  52  arranged further on the outside and a frustoconical section  54  arranged further on the inside. A gap  56  spaces the cylindrical section  52  of the thickened portion  32  of the contact connection  22  radially apart from the wall  10 . 
         [0070]    The seal  24  partially surrounds the thickened portion  32  of the contact connection  22 . The seal  24  is in the form of a cylinder. The cylinder is oriented parallel to the axis  36  of the channel  14  and has a cutout along the axis  36  of the channel  14 , through which the contact connection  22  is guided. The cutout has a cylindrical section arranged further on the outside and a frustoconical section which adjoins the cylindrical section and is arranged further on the inside. The two sections of the cutout divide the seal  24  into a sealing section  58  which is arranged further on the outside and surrounds the cylindrical section of the thickened portion  32  and a sealing section  60  which is arranged further on the inside and surrounds the frustoconical section of the thickened portion  32 . 
         [0071]    The contact connection  22 , during the movement thereof caused by the propellant charge gas pressure, presses the sealing section, which is arranged further on the inside, by the thickened portion  32  radially against the wall  10  and axially against the tapered portion  26  such that the compressive force exerted on the inner sealing section by the contact connection  22  therefore has both a directional component which is perpendicular to the axis  36  of the channel  14  and a directional component which is parallel to the first directional component. Reliable sealing of the electrical interface  16  is thereby achieved. 
         [0072]    The following is a summary list of reference numerals and the corresponding structure used in the above description of the invention:
     2  ammunition     4  propellant charge     6  projectile     8  holding device     10  wall (of  6 )     12  control electronics     14  channel (of  10 )     16  electrical interface     18  data line     20  electrical system     22  contact connection     24  seal     26  tapered portion     28  sealing seat (in  14  for  24 )     30  pressure element (of  22 )     32  thickened portion (of  22 )     34  shoulder (of  32 )     36  axis (of  14 )     38  sealing section (of  24 ) oriented parallel (to  36 )     40  sealing section (of  24 ) oriented perpendicular (to  36 )     42  gap (between  30  and  38 )     44  gap (between  10  and  30 )     46  sealing seat arranged further on the outside (in  14  for  24 )     48  sealing seat arranged further on the inside (in  14  for  24 )     50  gap (between  10  and  32  and between  10  and  38 )     52  cylindrical section (of  32 )     54  frustoconical section (of  32 )     56  gap (between  10  and  32 )     58  sealing section (of  24 ) arranged further on the outside     60  sealing section (of  24 ) arranged further on the inside