Abstract:
The invention relates to a quick coupling for fluid pipes, comprising: a connector with a connecting piece and at least one connecting pipe transversely projecting from said connecting piece, the connecting piece being of the type that can be introduced into a receiving opening of a counterpart in a sealing manner and brought into latching engagement with said counterpart by means of a latching means; a securing means that can be converted from a locking position in which the latching engagement is secured against unlocking to an unlocking position in which the latching engagement can be disengaged; and a fastening means to which said securing means can be fixed in at least one position. To improve a quick coupling of the kind as mentioned above in such a manner that the securing means, after having inserted the connector into the receiving opening of the counterpart, can be mounted to the connector more easily, the fastening means is located, according to the invention, on a side of the connecting pipe facing away from the connecting piece.

Description:
[0001]    The invention relates to a quick coupling for fluid pipes, comprising: a connector with a connecting piece and at least one connecting pipe transversely projecting from said connecting piece, the connecting piece being of the type that can be introduced into a receiving opening of a counterpart in a sealing manner and brought into latching engagement with said counterpart by means of a locking or latching means; a securing means that can be converted from a locking position in which the latching engagement is secured against unlocking to an unlocking position in which the latching engagement can be disengaged or released; and a fastening means to which said securing means can be fixed in at least one position. 
         [0002]    Such a quick coupling is known from WO 2007/042344 A1. According to said quick coupling, the securing means can be fixed in different positions at the connector in a locking manner. The fastening means of the quick coupling is formed by locking grooves provided at the connecting piece which have to be applied thereto before the securing means is being assembled. After being inserted into the receiving opening of the counterpart, the connecting piece is no longer fully accessible so that the securing means should preferably be applied to the connecting piece before the connecting piece is inserted into the counterpart&#39;s receiving opening. 
         [0003]    The invention is based on the object to improve a quick coupling of the kind mentioned above in such a manner that, after the connecting piece has been introduced into the counterpart&#39;s receiving opening, the securing means can be mounted to the connector more easily. 
         [0004]    To solve the object basing the invention, a quick coupling for fluid pipes is provided, comprising: a connector with a connecting piece and at least one connecting pipe transversely projecting from said connecting piece, the connecting piece being of the type that can be introduced into a receiving opening of a counterpart in a sealing manner and brought into latching engagement with said counterpart by means of a latching means; a securing means that can be converted from a locking position in which the latching engagement is secured against unlocking to an unlocking position in which the latching engagement can be disengaged; and a fastening means to which said securing means can be fixed in at least one position, the fastening means being arranged on a side of the connecting pipe facing away from said connecting piece. The fastening means can be located directly on the connecting pipe or on another part of the connector that is above the connecting pipe or on the side of the connecting pipe facing away from the connecting piece. Accordingly, after the connecting piece has been introduced into the counterpart&#39;s receiving opening, the securing means can be mounted to the connector and actuated more easily, thereby facilitating mounting and handling of the quick coupling. Besides, checking the state of the securing means has become easier, as the part of the connector on the side of the connecting pipe facing away from the connecting piece can be viewed better and is more accessible than the part of the connector on the side of the connecting pipe facing the connecting piece. 
         [0005]    Any advantageous developments of the invention are subject-matters of the sub-claims. 
         [0006]    It may turn out to be advantageous to have the securing means fixed to the fastening means when being in its locking position and/or in its unlocking position preferably in non-positive and/or in positive, preferentially in locking manner. Thus, it is particularly easy for the user to find out via tactile feedback generated during the engagement or disengagement whether the securing means is in its securing and/or in its unlocking position. To this end, the securing means may comprise at least one, preferably flexible latching or locking section that can be locked in at least one locking position at the fastening means. Preferably, the latching section complies with at least one of the following requirements:
       The latching section has its inner contour adapted to the outer contour of the connector and can be movably guided on the connector.   The latching section is formed resiliently.   The latching section is of an anchor structure.   The latching section includes at least one latching or snap-in protrusion and/or at least one snap-in reception which can be fixed in engaging manner to the securing means, the snap-in protrusion and/or the snap-in reception preferably being provided on a side of the latching section facing the fastening means.   The latching section comprises a preferably ribbed web extending from a base to a free end.   The latching section comprises at least one side arm branching off from the web substantially in the direction of the web base.   The latching section comprises a securing portion for locking the latching means in its locking position, said securing means preferably being arranged at the free end of the web.       
 
         [0014]    The securing means may comprise multiple identical or different latching or locking sections. The securing means can be designed such that it overlaps the connector on the side of the connecting pipe facing away from the connecting piece. The latching sections may be provided on diametrically opposed sides of the connecting piece. Preferably, the latching section is arranged between two guide sections. The latching section and the guide sections preferably may substantially extend parallel to each other from the same base. The guide sections can be movably guided through the connector and/or the fastening means. The snap-in protrusion and/or the snap-in reception can be provided at the latching section and/or the guide section. 
         [0015]    In an advantageous development of the invention, the securing means is guided between locking and unlocking position, at least section-wise, through the fastening means and/or through the connector, preferably through the connecting piece and/or through the connecting pipe. Connector and fastening means may form a guiding link having diverse guide sections used to support the securing means when converting between locking and unlocking position in torsion-proof, tilt-proof and/or sliding manner. Said guide sections preferably extend parallel to the direction into which the securing means is converted between locking and unlocking position, preferably parallel to the axis of the connecting piece. At least one guide section may be provided at an outer contour of the connecting piece, at the connecting pipe and/or at the fastening means. The guide section is preferably facing the connecting piece. 
         [0016]    It may be proven beneficial to have the securing means converted between locking and unlocking position by being displaced or moved along the axis of the connecting piece. Thus, converting the securing means from the unlocking position to the locking position can be combined with an introducing movement of the connecting piece into the counterpart&#39;s receiving opening. However, it is also possible to combine converting the securing means from the locking position to the unlocking position with the retracting movement of the connecting piece from the counterpart&#39;s receiving opening, thus facilitating the handling of the quick coupling. 
         [0017]    It may be advantageous to have the fastening means detachably connected to the connector, preferably to the connecting piece and/or to the connecting pipe. This allows to design the fastening means e.g. in the form of an add-on component and/or of an adapter so that one and the same securing means fits to different connectors. 
         [0018]    It may be convenient to have the fastening means plugged onto the connector, preferably onto the connecting piece and/or the connecting pipe. Accordingly, the fastening means can be mounted onto or dismounted from the connector without any assistive and connecting equipment being required, thus further facilitating mounting or dismounting of the quick coupling. 
         [0019]    It may be proven beneficial to have the fastening means connected to the connector, preferably to the connecting piece and/or the connecting pipe, in a permanent, captive and/or non-detachable manner. The fastening means may, at least section-wise, also be integrally formed with the connector, thereby reducing the danger of accidental disengagement of the fastening means from the connector and, thus, of any conceivable disengagement of the latching engagement between connector and counterpart. 
         [0020]    It may be helpful to have the fastening means enclosing the connecting piece and/or the connecting pipe to its full extent. Preferably, the fastening means can be sealed around the connecting piece and/or the connecting pipe. To this end, parts of the fastening means that are complementary to one another can be connected around the connecting piece and/or the connecting pipe in either detachable or non-detachable manner. Preferentially, the fastening means encloses the connecting piece and/or two connecting pipes protruding from the connecting piece in various or diametrically opposed directions to its/their full extent. This allows the fastening means to be connected to the connector in non-detachable manner. 
         [0021]    It may be useful to have the quick coupling comprise a locking mechanism for locking the securing means in at least one position, preferably in the locking position, with regard to the fastening means. Thus, a third securing can be obtained so that the danger of unintentional solving of the latching engagement between latching means and counterpart can be reduced even more. 
         [0022]    It may be convenient to have the securing means and the fastening means comprise surfaces that are lying flush against each other in one position, preferably in the locking position of the securing means. This enables the user to easily recognize whether or not the securing means is in the desired position. Preferably, said surfaces project away from the connecting piece in counter-insertion direction. 
         [0023]    It may be proven advantageous to have the connecting pipe comprise at least one guide surface for movably guiding the securing means during the conversion between locking and unlocking position and/or to position the fastening means with regard to the connector in a torsion-proof and/or slide-proof manner. The guide surface may substantially be directed parallel to the axis of the connecting piece and/or orthogonal to the axis of the connecting pipe. As said guide surface is preferably spaced apart from the connecting piece, the securing means can be supported in a particularly torsion- and tilt-proof manner. 
         [0024]    It may be proven favorable to have the connecting pipe comprise two guide surfaces being spaced apart along the axis of said connecting pipe. Said guide surfaces can be directed substantially parallel to the axis of the connecting piece and/or orthogonal to the axis of the connecting pipe. Said guide surfaces may also form a seat for a connecting section of the fastening means. Preferably, two connecting sections of the fastening means are positioned on two connecting pipes projecting from the connecting piece into various or diametrically opposed directions, between two guide surfaces, respectively, in torsion-proof and slide-proof manner. Thus, the fastening means can be fixed in a definite position to the connector. 
         [0025]    It may be proven advantageous to have the latching means comprise two resilient latch arms protruding from the connecting piece in circumferential direction of the connecting piece and displaced to the connecting pipe. Preferably, the latch arms protrude in counter-insertion direction of the connecting piece and are resiliently designed in radial direction. The latch arms are preferably arranged in the circumferential direction of the connecting piece, preferably centrally between two connecting pipes. As a result, the connector can be kept in the middle of the counterpart&#39;s receiving opening. Furthermore, in this central position between two connecting pipes, the latch arms are easier accessible for the securing means. 
         [0026]    It may be convenient to have the connector substantially designed in either X-, T-, Y- or L-shape, the connector preferably including two connecting pipes, the axes thereof being in one plane with the axis of the connecting piece, or the axes thereof being in two planes cutting in the region of the axis of the connecting piece. Thus, various connector configurations can be achieved. 
         [0027]    An independent issue of the present invention relates to a construction kit for a quick coupling for fluid pipes, comprising: a connector with a connecting piece and at least one connecting pipe transversely projecting from said connecting piece, the connecting piece being of the type that can be introduced into a receiving opening of a counterpart in a sealing manner and brought into latching engagement with said counterpart by means of a latching means; a securing means for securing the latching engagement against unlocking; and a fastening means for fixing the securing means in at least one position, the connector, the securing means and the fastening means being connectable to each other such that the securing means is convertible between a locking position in which the latching engagement is secured against unlocking and an unlocking position in which the latching engagement can be released and that the securing means can be fixed to the fastening means in at least one position. Preferably, the fastening means can be arranged on a side of the connecting pipe facing away from the connecting piece. The above-mentioned advantages can, thus, be achieved. The quick coupling and the components thereof may comprise all of the above-mentioned features. 
         [0028]    Preferred developments can be derived by combining the features according to the sub-claims with features according to the description. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0029]      FIG. 1   a  is a perspective view of the quick coupling according to a first embodiment of the invention having a compatible counterpart, with the securing means being in the unlocking position. 
           [0030]      FIG. 1   b  is a simplified sectional view of the quick coupling of  FIG. 1   a.    
           [0031]      FIG. 2   a  is a perspective view of the quick coupling of  FIG. 1   a , with the securing means being in the locking position. 
           [0032]      FIG. 2   b  is a simplified sectional view of the quick coupling of  FIG. 2   a.    
           [0033]      FIG. 3  is an enlarged detail of the securing means of the quick coupling according to  FIGS. 1   a  and  1   b.    
           [0034]      FIG. 4  is a perspective view of a quick coupling according to another embodiment of the invention, with the connector having two connecting pipes the axes of which lying in different planes cutting in the region of the axis of the connecting piece. 
           [0035]      FIG. 5  shows a quick coupling according to a third embodiment of the invention having a connector according to  FIG. 4 , with the fastening means being mounted onto the connector in non-detachable manner. 
           [0036]      FIG. 6  shows a detail of a fastening means according to the third embodiment of the invention. 
           [0037]      FIG. 7  shows a quick coupling according to a fourth embodiment of the invention, with the securing means being in the unlocking position and a latching means being in the unlatching position. 
           [0038]      FIG. 8  shows the quick coupling of  FIG. 7 , with the securing means being in the locking position and the latching means being in the latching position. 
           [0039]      FIG. 9  shows a quick coupling according to a fifth embodiment of the invention, with the fastening means being mounted onto the connector in non-detachable manner and comprising welded components. 
           [0040]      FIG. 10  shows a quick coupling according to a sixth embodiment of the invention, with the securing means being in the unlocking position. 
           [0041]      FIG. 11  is a perspective view of the fastening means of the quick coupling according to  FIG. 10 . 
           [0042]      FIG. 12  is a perspective view of the securing means of the quick coupling according to  FIG. 10 . 
           [0043]      FIG. 13  shows the quick coupling according to  FIG. 10  being inserted into the receiving opening of a counterpart, with the securing means being in the locking position. 
           [0044]      FIG. 14   a  shows a quick coupling according to a seventh embodiment of the invention, with the securing means being in the unlocking position. 
           [0045]      FIG. 14   b  is a schematic sectional view of the quick coupling according to  FIG. 14   a.    
           [0046]      FIG. 15   a  shows the quick coupling according to  FIG. 14   a , with the securing means being in the locking position. 
           [0047]      FIG. 15   b  is a schematic sectional view of the quick coupling according to  FIG. 15   a.    
           [0048]      FIG. 16  is a perspective view of a quick coupling according to an eighth embodiment of the invention. 
           [0049]      FIG. 17  is another perspective view of the quick coupling according to  FIG. 16 . 
           [0050]      FIG. 18  is a perspective view of a quick coupling according to a ninth embodiment of the invention, with the securing means being in the unlocking position. 
           [0051]      FIG. 19  shows the quick coupling according to  FIG. 18 , with the securing means being in the locking position. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Embodiment 1 
       [0052]    The first embodiment of the invention described in the following with regard to  FIGS. 1 to 3  relates to a quick coupling  1  for fluid pipes in the form of a leak-oil connector.  FIG. 1   a  is a perspective view of the inventive quick coupling  1  as well as of a counterpart  6  with a suitable receiving opening  5 , with the securing means  8  being in the unlocking position. 
         [0053]    The inventive quick coupling  1  comprises an integrally formed, substantially T-shaped connector  2  of a glass-fiber reinforced plastic (e.g. PA66+6 GF30 or Polyamide 66+6 with a 30% glass-fiber portion) including a connecting piece  3  and two connecting pipes  4  transversely protruding from said connecting piece  3 . 
         [0054]    Connecting piece  3  is introducible into receiving opening  5  of counterpart  6  in a sealing manner. In the direction of introduction of quick coupling  1 , indicated by an arrow, a sealing ring  31  is held in a circumferential groove  32  at the end of connecting piece  3 . 
         [0055]    Any leak-oil pipes to be connected can be attached to the cone-shape end pieces of connecting pipes  4 . Axes A 4  of connecting pipes  4  and axis A 3  of connecting piece  3  are lying in one and the same plane. To this end, axes A 4  of connecting pipes  4  each form an angle of 90° with axis A 3  of connecting piece  3 . Axis A 3  of connecting piece  3  coincides, when being in the inserted condition, with axis A 5  of receiving opening  5  as intended. 
         [0056]    Receiving opening  5  defined in counterpart  6  comprises, starting from a surface  60  of counterpart  6 , a chamfer  61  in the entrance region, a snap-in protrusion  62 , a cone-shape widening  63 , an undercut  64 , a cone-shape tapering  65  and a holding area  66 . 
         [0057]    Two identically formed resilient latching or latch arms  7  protrude on diametrically opposed sides of the axis of connecting piece  3  from connecting piece  3  in counter-insertion direction and can be brought into latching engagement with counterpart  6 . Each of said latch arms  7  comprises a wedge face  71  substantially being formed at the free end of latch arm  7  adjacent to the largest radius of latch arm  7  and protruding away from the direction of insertion of connecting piece  3 . Wedge face  71  has an angle of about 45° to axis A 3  of connecting piece  3 . Further, each latch arm  7  is provided at the outside with two wedge faces  72 ,  73  protruding away from connecting piece  3  in the direction of insertion, with wedge face  72  being formed adjacent to the greatest radius of latch arm  7  and wedge face  73  being formed directly adjacent to the cylindrical part of connecting piece  3 . Wedge faces  72 ,  73  each comprise an angle of about 20° with regard to axis A 3  of connecting piece  3 . Due to the different angles of inclination of wedge faces  72 ,  73  with regard to axis A 3  of connecting piece  3 , an inserting force of connecting piece  3  is smaller than a retracting force of connecting piece  3 . Glide surfaces  74  and  75  are provided between wedge faces  71 ,  72  and  73  and extend substantially parallel to axis A 3  of connecting piece  3 , glide surface  74  defining the largest radius of latch arm  7 . The outer contour of latch arm  7  has been adapted to the inner contour of receiving opening  5 . In inner side  76  of latch arm  7  facing towards connecting piece  3  is in the form of a wedge face and is continuously inclined from its low end up to the end of latch arm  7  with regard to the axis of connecting piece  3 , preferably at an angle of about 10°. 
         [0058]    Securing means  8  is integrally formed of plastic or metal and overlaps connector  2  on a side of connecting pipe  4  facing away from connecting piece  3 . To this end, securing means  8  comprises multiple snap-in protrusions  81   a ,  81   b ,  81   c  restricting or defining a variety of snap-in receptions  82   a ,  82   b ,  82   c . Snap-in protrusions  81   a ,  81   b ,  81   c  and snap-in receptions  82   a ,  82   b ,  82   c  are provided at the inner sides facing each other of two resilient, substantially anchor-shaped latching sections. Said latching sections each comprise a ribbed web  83  at the end of which a securing portion  85  is provided, as well as two side arms  84 . Side arms  84  are each fastened substantially in a center region of web  83  and extend opposite to the direction of extension of web  83  so as to form the anchor-shaped structure. Both, web  83  and side arms  84  have resilient properties. Two guide sections  86  respectively protrude from a substantially flat actuating section  87  in parallel, in the same direction and in the same plane alongside of each latching section so that two guide sections  86  laterally flank each of said latching sections. Actuating section  87  constitutes the common basis of all latching sections and guide sections  86 . Securing means  8  is located on fastening means  9  in torsion-proof, movable and captive manner and can be converted either by displacement or movement in the or opposite to the direction of insertion between the unlocking position in which the latching engagement of quick coupling  1  can be unlocked and the locking position in which such latching engagement is secured. Snap-in protrusions  81   a ,  81   b ,  81   c  and snap-in receptions  82   a ,  82   b ,  82   c  provided at the inner sides of the latching sections facing each other serve to fix and catch securing means  8  in the unlocking and in the locking position at fastening means  9 . 
         [0059]    Fastening means  9  integrally formed of plastic or metal comprises a substantially flat fastening section  91  to which securing means  8  can be fixed in a locked manner. Fastening section  91  substantially extends in a plane orthogonally arranged to axis A 3  of connecting piece  3 . Stiffening longitudinally and transversely running ribs  92  preferably extend perpendicularly to fastening section  91 . Each of said two ends of fastening section  91  is provided with an actuating section  93  having a surface lying, when in locking position, flush against a surface of securing means  8 , and having a connecting section  94  that can be fixed on one of said connecting pipes  4  in a locking manner. Each of said connecting sections  94  exactly fits between two guide surfaces  41 ,  41  integrally formed with connecting pipes  4  and extending perpendicularly to axes A 4  of connecting pipes  4 . Contours and dimensions of connector  2 , fastening means  9  and securing means  8  match to each other such that connector  2  and fastening means  9  constitute a guiding link for securing means  8  so that securing means  8  can be converted between unlocking and locking position in torsion-proof, tilt-proof and sliding manner. To this end, guide sections  86  of securing means  8  are received in sliding manner between actuating sections  93  and fastening means  9  and between inner guide surfaces  41 . The latching sections have an inner contour matching to the outer contour of connecting piece  3  and slide or glide on the diametrically opposing outer sides of connecting piece  3 . 
         [0060]    The preferred application of the invention will be described in the following in detail with regard to the drawings. 
         [0061]    The quick coupling  1  is inserted in the direction of insertion into receiving opening  5  of counterpart  6 , while securing means  8  is preferably caught in the unlocking position at fastening means  9 . During the insertion, connecting piece  3  is first centered in receiving opening  5  by means of wedge faces  72 ,  73  facing away from connecting piece  3 . Wedge faces  72  facing away from connecting piece  3  in the direction of insertion lie flat against snap-in protrusion  62  without any force being applied in the direction of insertion (insertion force). Applying an insertion force causes interaction of latch arms  7  with snap-in protrusion  62  via wedge engagements so that latch arms  7  are radially displaced towards the inside, in order to slide with glide surface  75  over snap-in protrusion  62 . Owing to the resilient properties of latch arms  7 , same return to a position projecting away from connecting piece  3  so that latch arms  7  find their way into undercut  64  behind snap-in protrusion  62  where they are caught or locked in place. Wedge faces  71  facing away from connecting piece  3  in counter-insertion direction get into engagement with snap-in protrusion  62  and widening  63 , with latch arms  7  being entirely accommodated in receiving opening  5  and not projecting from receiving opening  5  over surface  60  of counterpart  6 . Thus, quick coupling  1  is in latching engagement with counterpart  6 . According to the unlocking position, schematically shown in  FIG. 1   a , fastening section  91  is positioned in the second snap-in reception  82   b . Securing means  8  is not in latching engagement with latch arms  7  so that latch arms  7  can be radially urged towards the inside. 
         [0062]    Securing means  8  is now converted by means of displacement or movement with regard to fastening means  9  in the direction of insertion from the unlocking to the locking position. When converting the securing means  8  from the unlocking to the locking position, securing sections  85  interact with latch arms  7  such that latch arms  7  cannot be displaced or urged towards the inside in radial direction when they are in the locking position. Moreover, latch arms  7  are spread-off or opened and urged deeper into receiving opening  5  by means of a wedge engagement with snap-in protrusion  62 . Thus, a secondary securing can be realized. In the locking position, fastening section  91  is positioned in the first snap-in reception  82   a  so that securing means  8  is fixed or caught to fastening means  9 . In the locking position, the surface of actuating section  87  of securing means  8  facing away from connecting piece  3  extends flush against the surfaces of actuating sections  93  of fastening means  9  facing away from connecting piece  3 . 
         [0063]    Securing means  8  may again be converted from the locking position to the unlocking position by movement in counter-insertion direction of securing means  8 . In the unlocking position, securing means  8  is not in engagement with latch arms  7  so that latch arms  7  can be radially urged towards the inside. Applying a force in counter-insertion direction (pull-out force) causes that quick coupling  1  can be pulled out of reception opening  5 . In the unlocking position, securing means  8  is again fixed or caught to fastening means  9 , with fastening section  91  being located in the second snap-in reception  82   b . Accordingly, securing means  8  can, thus, be converted from the unlocking position to the locking position in a reversible manner. 
         [0064]    The subsequently following embodiments are substantially based on the first embodiment. Features serving for the same function were given the same reference numbers as in case of the first embodiment. From now on, only essential differences with regard to the first embodiment will be explained in more detail and, where possible, it is refrained from giving repetitions of the preceding description. 
       Embodiment 2 
       [0065]    The second embodiment of the invention will be described in the following with regard to  FIG. 4 . The statements refer to a condition in which securing means  8  is fixed to fastening means  9  which is mounted to connector  2 . Deviating from the first embodiment, axes A 4  of connecting pipes  4  extend in a plane perpendicular to axis A 3  of connecting piece  3  or in various planes cutting in axis A 3  of connecting piece  3 . To compensate the different angles of axes A 4  of connecting pipes  4 , fastening section  91  of fastening means  9  is bent according to the course of axes A 4 . Moreover, at the side of a connecting pipe  4 , guide sections  86  of securing means  8  are aligned substantially parallel to the plane spanned by axis A 4  of the appertaining connecting pipe  4  and axis A 3  of connecting piece  3 . The latching sections also extend parallel to said plane. Further, at the side of the other connecting pipe  4 , guide sections  86  are aligned substantially parallel to the plane spanned by axis A 4  of the other connecting pipe  4  and axis A 3  of connecting piece  3 . As in the first embodiment, contours and dimensions of connector  2 , fastening means  9  and securing means  8  match each other such that connector  2  and fastening means  9  form a guiding link for securing means  8  by which securing means  8  can be converted between unlocking and locking position in a torsion-proof, tilt-proof and sliding manner. 
       Embodiment 3 
       [0066]    The third embodiment of the invention that is based on the second embodiment according to  FIG. 4  will be described in the following with regard to  FIGS. 5 and 6 . Deviating from the second embodiment, fastening means  9  is mounted to connecting pipes  4  in an unsolvable manner. To this end, connecting section  94  of each fastening means  9  is caught in a positive-locking manner with a substantially W-shaped yoke  95  and closed around the circumference of the appertaining connecting pipe  4 . As shown in  FIG. 6 , yoke  95  closes a receiving opening of connecting section  94  into which connecting pipe  4  has been received, a wedge-shaped protrusion  95   a  of yoke  95  being in a wedge engagement with two wedge faces  94   a  facing away from the reception at the ends of the legs of connecting section  94 . Snap-in protrusions  95   b  provided at the inner sides of the free ends of yoke  95  are caught by snap-in protrusions  94   b  provided at the outer sides of the legs of connecting section  94 . When yoke  95  snaps onto connecting section  94 , snap-in protrusions  94   b ,  95   b  interact via wedge faces such that yoke  95  is easier to be locked to than to be unlocked from connecting section  94 . 
       Embodiment 4 
       [0067]    The fourth embodiment of the invention that is also based on the second embodiment according to  FIG. 4  will be explained in the following with regard to  FIGS. 7 and 8 . In addition to the second embodiment, fastening means  9  comprises a latching means  97  that can be converted between an unlatched state ( FIG. 7 ), in which securing means  8  can be converted between the locking and the unlocking position, and a latched state ( FIG. 8 ) in which securing means  8  is latched in the locking or latching state. In the locking position of securing means  8 , the surfaces of actuating sections  87 ,  93  of securing means  8  and of fastening means  9  facing away from connecting piece  3  extend flush against each other. In this state, latching means  97  movably guided on an actuating section  93  of fastening means  9  can be moved over actuating section  87  of securing means  8  such that the movement of securing means  8  with regard to fastening means  9  is either locked, blocked and/or caught. Accordingly, securing means  8  cannot be converted from the locking position into the unlocking position. Thus, a tertiary securing has been realized. 
       Embodiment 5 
       [0068]    The fifth embodiment of the invention that is also based on the second embodiment according to  FIG. 4  will be explained in the following with regard to  FIG. 9 . Deviating from the second embodiment, fastening means  9  comprises two complementary components  9   a ,  9   b  that can be arranged around connecting pipes  4  from different sides and welded to each other so as to connect fastening means  9  with connector  3  in a non-detachable manner. For mounting the components that can be welded, weld projections or cams of one component  9   b  are inserted through complementary weld projection openings of the other component  9   a  and then welded to each other so as to combine the two components in a positive locking and firmly joint manner. As to this, the lower component  9   b  comprises an opening through which connector  2  and securing sections  85  of securing means  8  are extending. In the condition as shown, fastening means  9  is closed around the entire circumference of connecting piece  3  and around the two connecting pipes  4 . Components  9   a ,  9   b  can be fixed via inner and outer guide faces  41 ,  42  in exactly one position to connector  2  in a slide-proof and torsion-proof manner. Contours and dimensions of connector  2 , fastening means  9  and securing means  8  match to each other such that connector  2  and fastening means  9  form a guiding link for securing means  8  by which securing means  8  can be converted between the unlocking and the locking position in torsion-proof, tilt-proof and sliding manner. 
       Embodiment 6 
       [0069]    The sixth embodiment of the invention that is also based on the second embodiment according to  FIG. 4  will be explained in the following with regard to  FIGS. 10 to 13 .  FIG. 10  shows quick coupling  1  in the unlocking position of securing means  8 .  FIG. 11  is a perspective view of fastening means  9 .  FIG. 12  is a perspective view of securing means  8 . Deviating from the second embodiment, securing means  8  comprises different latching sections and guide sections  86   a ,  86   b ,  86   c ,  86   d  arranged on different sides of connector  2  and fastening means  9 . The latching section on the inner side of the curve of connector  2  (i.e. the side of the smaller angular distance of axes A 4  of connecting pipes  4 ) comprises a ribbed web  83  with a securing portion  85  at its end and a side arm  84 . Side arm  84  is provided between web  83  and first guide section  86   a . Together with web  83  and arm  84 , first guide section  86   a  forms a structure of about G-shaped form, the slot-shaped opening thereof extending in a direction facing away from actuating section  87 . Second guide section  86   b  is connected to web  83  over its entire length and extends in another plane than first guide section  86   a . The latching section on the outer side of the curve of connector  2  (i.e. the side of the larger angular distance of axes A 4  of connecting pipes  4 ) is, as in case of the first embodiment, of anchor-shaped form. Third guide section  86   c  extends parallel to first guide section  86   a  and forms, together with web  83  and arm  84 , a structure of about G-shaped form, the slot-shaped opening thereof extending in a direction facing away from actuating section  87 . Fourth guide section  86   d  is provided, spaced apart from the latching section, on the outer side of the curve and extends parallel to second guide section  86   b . Snap-in protrusions  81   a ,  81   b ,  81   c  are located at the opposing inner sides of latching sections and/or guide sections  86   a ,  86   b ,  86   c ,  86   d .  FIG. 13  shows quick coupling  1  when mounted into receiving opening  5  of counterpart  6 , with securing means  8  being in the locking position. 
       Embodiment 7 
       [0070]    The seventh embodiment of the invention that is substantially based on the first embodiment according to  FIGS. 1 to 3  will be described in the following with regard to  FIGS. 14 and 15 . Deviating from the first embodiment, connector  2  is of a substantially cross-shaped structure, with fastening means  9  being partially molded on a side of connecting pipes  4  facing away from connecting piece  3 . Connector  2  is substantially of an X-shaped form.  FIG. 14   a  is a perspective view of quick coupling  1 , with securing means  8  being in the unlocking position.  FIG. 14   b  is a schematic sectional view of quick coupling  1  of  FIG. 14   a .  FIG. 15   a  is a perspective view of quick coupling  1 , with securing means  8  being in the locking position.  FIG. 15   b  is a schematic sectional view of quick coupling  1  of  FIG. 15   a.    
         [0071]    Deviating from the first embodiment, securing means  8  comprises two latching sections each having a ribbed web  83  and a securing portion  85  at the end thereof, web  83  extending, as intended, parallel to axis A 3  of connecting piece  3  and being of an inner contour adapted to the outer contour of connector  2  in order to be able to slide onto the outer side of connector  2 . At the upper end of each of said webs  83  there is provided an actuating section  87 . The two actuating sections  87  are connected to each other via two parallel guide sections  86 . 
         [0072]    Each of said inner sides of the latching sections facing each other is provided with a snap-in reception  82 . When in the unlocking or the locking position, snap-in receptions  82  can be brought into latching engagement with latching sections  91 ,  91   b  of fastening means  9 . 
         [0073]    Fastening means  9  comprises three walls  90   a ,  90   b  formed together with latching sections  91   a ,  91   b  projecting from connecting pipes  4  parallel to each other and spaced apart from each other perpendicularly to the axes A 4  of connecting pipes  4  on the side of connector  2  facing away from connector  2 . Outer walls  90   a  are integrally connected via ribs  90   c  to the circular-shaped and disk-shaped guide surfaces  41  of connecting pipes  4 . Each of said ribs  90   c  substantially extends in the plane spanned by axis A 3  of connecting piece  3  and axes A 4  of connecting pipes  4 . Latching sections  91   a ,  91   b  protrude substantially perpendicularly to said plane from both sides of walls  90   a ,  90   b . Two gap-shaped receptions are provided between outer walls  90   a  and center wall  90   b  for guiding guide sections  86  of securing means  8  in a sliding manner during the conversion between unlocking and locking position. 
         [0074]    For mounting quick coupling  1 , guide sections  86  of securing means  8  are inserted into the gap-shaped receptions between walls  90   a ,  90   b . Subsequently, a substantially plate-shaped lid  98  is snapped onto the outer walls  90   a  of fastening means  9  so as to close the gap-shaped reception between walls  90   a ,  90   b . Thus, securing means  8  is connected to fastening means  9  in non-releasable manner. 
         [0075]      FIG. 14   b  is a schematic sectional view of the quick coupling according to  FIG. 14   a  when in unlocking position. The section extends through one of the two walls  90   a . As can be seen, when in the unlocking position, securing means  8  is in latching engagement with fastening means  9 . To this end, snap-in receptions  82  are snapped onto latching sections  91   a . Securing means  8  is in abutment with lid  98  serving as stopper. Moving securing means  8  towards the direction of insertion (arrow) can cause securing means  8  to be converted from the unlocking to the locking position. 
         [0076]      FIG. 15   b  is a schematic sectional view of the quick coupling according to  FIG. 15   a  when in the unlocking position. Again, the section extends through one of the two walls  90   a . As can be seen, when in the locking position, securing means  8  is in latching engagement with fastening means  9 . To this end, snap-in receptions  82  are snapped onto latching sections  91   a . In this position, guide sections  86  are located at the bottoms of the gap-shaped receptions between walls  90   a ,  90   b . Moving securing means  8  against the direction of in insertion (arrow) can cause securing means  8  to be converted from the locking position to the unlocking position again. 
       Embodiment 8 
       [0077]    The eighth embodiment of the invention that is substantially based on the first embodiment according to  FIGS. 1 to 3  will be described in the following with regard to  FIGS. 16 and 17 .  FIGS. 16 and 17  are perspective views of quick coupling  1  seen from different sides. 
         [0078]    Deviating from the first embodiment, quick coupling  1  comprises just one connecting pipe  4 , axis A 4  of which substantially being arranged orthogonally to axis A 3  of connecting piece  3 . On the diametrically opposing side of the first connecting pipe  4 , a lug  21  with a T-shaped projection  22  is provided to which fastening means  9  can be fixed at one side thereof. When in the locking position, securing means  8  is in abutment with T-shaped projection  22 , with a surface of securing means  8  facing away from connector  2  in a counter-insertion direction lining up precisely with a surface of fastening means  9  facing away from connector  2  in a counter-insertion direction. Connector  2  is substantially of an L-shaped form. 
       Embodiment 9 
       [0079]    The ninth embodiment of the invention that is substantially based on the seventh embodiment according to  FIGS. 14 and 15  will be described in the following with regard to  FIGS. 18 and 19 .  FIGS. 18 and 19  are perspective views of quick coupling  1  seen from different sides. 
         [0080]    Deviating from the seventh embodiment, axes A 4  of connecting pipes  4  extend at an angle of about 135°, respectively, to axis A 3  of connecting piece  3 , axes A 4  of connecting pipes  4  and axis A 3  of connecting piece  3 , however, being in one plane. Connector  2  is substantially of a Y-shaped form. 
         [0081]    As in the first embodiment, securing means  8  comprises two latching sections, each having a ribbed web  83  at the end of which a securing portion  85  is provided, and to side arms  84 , web  83  extending, as intended, in the direction of insertion parallel to axis A 3  of connecting piece  3  and each of said latching sections having an inner contour adapted to the outer contour of connector  2  so as to be able to slide on the outer side of connector  2 . At the upper end of each of said webs  83  an actuating section  87  is provided, the two actuating sections  87  being connected to each other via a guide section. Each of said inner sides of said latching sections facing each other is provided with snap-in protrusions and snap-in receptions (not shown) that can be brought into latching engagement with latching sections of fastening means  9  when in the unlocking or the locking position. 
         [0082]    Fastening means  9  comprises two walls  90   a  provided with latching sections projecting from connecting pipes  4  parallel to each other and spaced apart from each other perpendicularly to the plane spanned by axis A 3  of connecting piece  3  and axes A 4  of connecting pipes  4  on the side of connector  2  facing away from connecting piece  3 . A gap-shaped reception is provided between walls  90   a  for movably guiding the guide section of securing means  8  when being converted between the unlocking and the locking position. Walls  90   a  are integrally connected via ribs  90   c  to connecting sections  94  that can be snapped onto connecting pipes  4 . Each of said ribs  90   c  substantially extends in the plane spanned by axis A 3  of connecting piece  3  and axes A 4  of connecting pipes  4 . 
         [0083]    For mounting quick coupling  1 , the guide section of securing means  8  is inserted into the gap-shaped reception between walls  90   a . Subsequently, a substantially plate-shaped lid  98  is snapped onto outer walls  90   a  and ribs  90   c  of fastening means  9  so as to close the gap-shaped reception between walls  90   a . Thus, securing means  8  is connected to fastening means  9  in non-releasable manner. 
         [0084]    When being in the unlocking position according to  FIG. 18 , securing means  8  is in latching engagement with fastening means  9 . To this end, securing means  8  is in abutment with lid  98  serving as a stopper. Moving securing means  8  in the direction of insertion (arrow) causes securing means  8  to be converted from the unlocking to the locking position. 
         [0085]    When being in the locking position according to  FIG. 19 , securing means  8  is also in latching engagement with fastening means  9 . In this position, the guide section is located at the bottom of the gap-shaped reception between walls  90   a . Moving securing means  8  in counter-insertion direction (arrow) causes securing means  8  to be converted from the locking position to the unlocking position again.