BACKGROUND OF THE INVENTION  
         [0001]    The present invention relates to a plug connection device for pressure medium conduits.  
           [0002]    European patent document EP 0 234 465 B1 discloses a plug connection device. This device has the disadvantage that in addition to a plug and a housing which receives the plug in anchored condition, an additional component is required. This additional component operates as a safety cap against unauthorized release of the connection and must be plugged over the plug and the housing. The plug connection device is therefore difficult to handle, and also because of the additional component additional and costly manufacturing steps are required.  
           [0003]    In addition, the plug of the prior art is injection molded, and therefore for each plug size a special injection molding tool is needed.  
         SUMMARY OF THE INVENTION  
         [0004]    Accordingly, it is an object of the present invention to provide a plug connection device which avoids the disadvantages of the prior art.  
           [0005]    In keeping with these objects and with others which will become apparent hereinafter, one feature of present invention resides, briefly stated, in a plug connection device which has a plug with a coupling region which, in not inserted condition of the plug, is formed as a substantially ring-shaped circumferential collar and, during insertion into an associated receiving portion of the housing, is deformed so as to form a holding means which engages the arresting edges, or the holding means are formed at one side of a tubular plug portion produced by extrusion.  
           [0006]    The plug connection device of the present invention has the advantage that the components which belong to the plug connection device, namely the plug and the housing can be produced in a cost favorable manner, and a simple handling with simultaneously reliably obtained anchoring is provided, without additional components such as a safety cap.  
           [0007]    Since the tubular plug portion alternatingly is first produced by extrusion and the holding means is then formed at the end side for example by thermal conversion, the manufacturing costs for the inventive plug connection are low. In particular cost intense manufacture of injection molding tools for different plug sizes can be dispensed with.  
           [0008]    The novel features which are considered as characteristic for the present invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, 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.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]    [0009]FIG. 1 is an exploded view of a first preferable embodiment of a plug connection device in accordance with the present invention with a plug and a housing as well as an O-sealing ring;  
         [0010]    [0010]FIG. 2 is a perspective view of the plug in a not plugged-in condition;  
         [0011]    [0011]FIG. 3 is a view showing a transverse cross-section of the inventive plug connection device;  
         [0012]    [0012]FIG. 4 is a view showing a longitudinal section of the plug connection device taken along the line IV-IV of FIG. 3, with arresting projections received in passages of a sleeve forming a part of a housing;  
         [0013]    [0013]FIG. 5 is a view showing a cross-section taken along the line V-V in FIG. 4;  
         [0014]    [0014]FIG. 6 is a view showing a longitudinal section of the plug connection device taken along the line VI-VI in FIG. 3, with bent back regions of the plug associated with guiding jaws of the sleeve;  
         [0015]    [0015]FIG. 7 shows a perspective view of a second alternative embodiment of the inventive plug connection device, with a housing provided for receiving of the plug and having a sleeve of a circular cross-section;  
         [0016]    [0016]FIG. 8 shows a plan view of the housing in accordance with the alternative embodiment;  
         [0017]    [0017]FIG. 9 is a view showing a cross-section taken along the line IX-IX in FIG. 8 through the sleeve; and  
         [0018]    [0018]FIG. 10 is a view showing a longitudinal section of the housing.  
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0019]    A plug connection device shown in FIG. 1 is identified as a whole with reference numeral  10 . It has a housing  11  which serves as a plug bushing, an O sealing ring  12 , and a plug  13 . The housing  11  includes the tubular portion  14  with a throughgoing opening  15  which extends axially along its longitudinal extension. A radially projecting sleeve  16  is formed of one piece with the outer wall of the tubular portion  14  and extends coaxially to the opening  15 . The sleeve  16  has an end side  18  which is open toward a coupling-side end  17  of the tubular portion  14  for receiving the plug  13 . It also has another end side which forms a connection to the tubular portion  14 . The end side  18  of the sleeve  16  which is open toward the coupling-side end of the housing  11  is formed as a hollow contour. The hollow contour is limited in a radial direction at one side by the outer wall of the tubular portion  14  and at the other side by the radial inner side of the sleeve  16 . Therefore the radial jacket surface of the sleeve  16  forms a circumferential outer collar.  
         [0020]    The outer collar has two throughgoing passages  20 ,  20 ′ which are located diametrically opposite to one another in a peripheral direction. The throughgoing passages  20 ,  21  in the outer collar are arranged in peripheral direction between two diametrically opposite guiding jaws  21 ,  21 ′ which have a reduced diameter relative to the remaining peripheral region of the outer collar. The guiding jaw  21 ,  21 ′ are formed as cylinder jacket segments arranged at the same radius. A region located in peripheral direction between this cylinder jacket  7  has a corresponding throughgoing passage  20 ,  20 ′ and is formed as a cylindrical jacket segment with a greater radius than the guiding jaws  21 ,  21 ′. The outer collar is therefore defined by two pairs of the cylindrical jacket segments of two different inner radii.  
         [0021]    An end  22  of the housing  11  which faces away from the plug  13  is provided for receiving a pressure medium conduit, while the opening  15  of the housing  11  serves as a flow passage for the pressure medium. A radial circumferential groove  23  is provided at the coupling-side end  17  of the housing  11  on the outer wall of the tubular portion  14 . It receives the O-sealing ring  12 . The plug  13  of the plug connection device  10  has a tube  24  with an inner diameter substantially corresponding to the outer diameter of the associated tubular portion  14  of the housing  11 . Therefore the tube  24  of the plug  13  is pluggable on or displaceable on the tubular portion  14  of the housing  11 .  
         [0022]    As can be seen from FIG. 2, the tube  24  of the plug  13  in a not-plugged in condition is provided at its coupling-side end  25  with a radial outwardly projecting and circumferential collar  26 . The collar  26  is connected with the tube  24  of one piece and preferably is composed of a flexible material. The collar  26  has a greater outer radius than the open end side  18  of the hollow contour of the housing  11  and comes therefore first, as can be seen from FIG. 1 during fitting or plugging of the plug on the tubular portion  14  of the housing  11 , to abutment at the end side  18  of the sleeve  16  which faces the collar. During a further axial displacement of the plug  13  in direction to the sleeve  16  the collar  26  is bent back in correspondence with the inner course of the hollow contour, and the regions  26  of the collar  26  which abut against the guiding jaws  21 ,  21 ′ of the sleeve  16 , because of the narrow inner diameter of the guiding jaws  21 ,  21 ′, are angled more than the regions  26 ″ of the collar  26  which abut against the both remaining segments of the hollow contour with a greater diameter. Thereby the regions  26 ″ associated with the segments of the sleeve  16  of the greater diameter extend at a greater angle from the tube longitudinal axis and form diametrically opposite arresting projections.  
         [0023]    During insertion or coupling of the plug  13  and the sleeve  16  of the housing  11 , the diametrically opposite arresting projections arrestingly engage in the throughgoing passages  20 ,  20 ′. The collar-side end  25  of the tube  24  abuts as an end abutment against the closed end side of the sleeve  16 , and the arresting projections  26 ″ form an opposite abutment with inner sides of the throughgoing passages  20 ,  20 ′ which face correspondingly the open end side  18  of the sleeve  16 . In this coupled condition the O-sealing ring  12  arranged in the ring grooves  23  is located between the outer wall of the tubular portion  14  of the housing  11  and the inner wall of the tube  24  of the plug  13 .  
         [0024]    [0024]FIG. 3 shows the inventive plug connection device  10  in anchored and thereby arrested condition, in which the plug  13  is plugged in the housing  11  and arrested in it. For this purpose the collar  26  of the plug  13  is received in the outer collar of the sleeve  16 , and the collar  26  is deformed. In particular, it deforms so that the regions  26 ′ of the collar  26  which face the guiding jaws  21 ,  21 ′ abut angularly against the inner surfaces of the guiding jaws  21 ,  21 ′, and the intermediately arranged regions of the collar  26  engage as arresting projections extending from the tube  24  through the associated throughgoing passages  20 ,  20 ′ in the outer collar of the sleeve  16 . Since each of the flange-like arresting projections  26 ″ is engaged in a form-locking manner by two opposite inner sides which limit the opening cross-section of the corresponding throughgoing passage  20 ,  20 ′ in a radial direction, a reliable rotation prevention against a radial turning of the plug  13  in the anchored condition is obtained.  
         [0025]    [0025]FIG. 4 illustrates the anchored and thereby arrested condition of the plug connection device  10 , in which the arresting projections  26 ′ of the plug  13  are received in the sleeve  16  of the housing  11  and with their free ends engage through the throughgoing openings  20 ,  20 ′ of the outer collar. They each form an angle of approximately 45° to the outer wall of the tube  24 . Since the collar-side end of the plug  13  axially abuts against the closed end side of the sleeve  16  and the flange-like arresting projections  26 ″ of the collar  26  for this purpose form an axial opposite abutment with the inner sides of the throughgoing passages  20 ,  20 ′ which face the open end side of the sleeve  16 , a reliable securing against an axial turning of the plug in the anchored condition is obtained.  
         [0026]    [0026]FIG. 5 shows a circular-arc curvature of the guiding jaws  21 ,  21 ′ in the cross-section, which extends approximately over one quadrant and is concentric to the tubular portion  14  of the housing  11 . Due to the concentric course of the guiding jaws  21 ,  21 ′ to the corresponding adjacent outer wall portions of the tubular portion  14 , together with its diameter narrowing a correspondingly narrower ring gap portion is formed for receiving the correspondingly associated region of the collar  26  and the plug tube  24  which comes to abutment. As can be seen from FIG. 6, in the anchored and thereby arrested condition of the plug connection device  10 , the regions of the plug collar  26  which are pressed against the inner surfaces of the guiding jaws  21 ,  21 ′ and abut against them are bent back substantially parallel to the outer wall of the plug tube  24 . Therefore, a frictional connection between the guiding jaws  21 ,  21 ′ and the associated regions of the collar  26  of the plug  13  is provided. The collar-side end  25  of the plug tube  24  is located in abutment with the closed end side of the sleeve  16 .  
         [0027]    An alternative embodiment of the housing  11  for the plug connection device  10  is shown in FIGS.  7 - 10 . The parts which are identical to the parts of the embodiment of FIGS.  1 - 6  are identified with the same reference numerals. As can be seen particularly from FIG. 7, the housing  11  has a tubular portion  14  with a throughgoing opening  15  extending axially in a longitudinal direction. A ring-shaped sleeve  16  is arranged coaxially to the tubular portion  14 . It has an open end side which faces the coupling-side end of the tubular portion  14 , and a closed end side which faces to the free end  22  of the housing  11  and formed of one piece with the tubular portion  14 . The sleeve  16  is provided with two diametrically opposite throughgoing passages  20 ,  20 ′, located on its radial circumferential outer collar and provided for receiving the corresponding arresting projections  26 ″ of the plug  13 . This embodiment is different from the first embodiment substantially in that, the sleeve of the housing  11  has a circular cross-section so that both the guiding jaws  21  and the portions provided with the throughgoing passages  20  are arranged on the same radius. The plug of the plug connection device  10  is formed identically to the first embodiment.  
         [0028]    [0028]FIG. 8 shows that the throughgoing passages  20  have a substantially rectangular opening cross-section. The edge length of the opening cross-section facing in the peripheral direction is greater than the edge length oriented transversely to it. FIG. 9 illustrates the circular shape of the cross-section of the sleeve  16 . The passages  20  are arranged on the sleeve  16  diametrically opposite in a peripheral direction and the guiding jaws  21  are located between them. Since the outer collar of the sleeve  16  facing toward the guiding jaws  21  is arranged concentrically to the tubular portion  14 , the thereby formed intermediate space is formed as a circumferential ring gap for receiving the associated region of the collar  26 . FIG. 10 illustrates the sleeve  16  which is formed of one piece on the tubular portion  14  of the housing, with end sides which project in an axial direction and have inner edges forming corresponding axial abutments for the plug  13 .  
         [0029]    It is characteristic for the both embodiments of the invention that the plug  13  of the plug connection device  10  has a coupling region, which in not plugged-in condition of the plug  13  is formed as a substantially ring-shaped, circumferential collar  26 , and during insertion in the receiving portion  16  of the housing  11 , which is correspondingly formed as a sleeve is deformed so that, the flange-like arresting projections  26  which engage the arresting edges limiting the throughgoing openings are formed. For destruction-free release of the inventive plug connection device  10  from its anchored condition, a tool which preferably corresponds to the geometric arrangement of the throughgoing passages can be utilized.  
         [0030]    An alternative embodiment of the inventive plug connection device  10  can be formed so that, the arresting projections  26 ″ in correspondence with the embodiment of FIG. 1, as well as FIGS.  3 - 10  are formed by extruding the tube  24  of the plug which is composed preferably of polyamide and deforming at the tube end the collar  26  as well as the arresting projections  26 ′ for example by thermal deformation. Thereby in the not inserted condition of the plug  13  the arresting projections  26  are formed flange-like and substantially radially projecting, while the intermediate regions  26 ′ are turned in direction of the longitudinal axis of the plug. Therefore during insertion of the plug  13  in the associated housing, the regions  26 ′ come frictionally to abutment against the corresponding guiding jaws  21 ,  21 ′ of the housing, while the arresting projections  26 ″ arrestingly engage through the corresponding throughgoing openings  20 ,  20 ′ and spring in them.  
         [0031]    Furthermore, the end of the housing  11  provided for receiving the pressure medium conduit can have a receiving region  14  with radially expanding thickenings which are spaced equidistantly in the axial direction. They are formed as conical ring shoulders and with their conically narrowing sides face toward the end  22 . Thereby because of such a profiling, a tight and non releasable anchoring of a pressure medium conduit fitted on the end  22  of the housing  11  is guaranteed.  
         [0032]    It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of constructions differing from the types described above.  
         [0033]    While the invention has been illustrated and described as embodied in plug connection device, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.  
         [0034]    Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention.
A plug connection device for pressure medium conduits, for binding or connection of fuel conduits has a housing provided with arresting edges, a plug insertable in the housing and having holding elements which form-lockingly engage the arresting edges, the plug having a coupling region which in a not plugged in condition of the plug is formed as a substantially ring-shaped circumferential collar and during insertion in an associated receiving portion of the housing is deformed so that the holding elements engaging the arresting edges are formed, or the holding elements are formed at an end side on a tubular plug portion produced by extrusion.