Abstract:
A fastening element for attaching to a wall. The fastening element having a contact element having an adhesive surface and a filling opening via which a flowable adhesive agent is capable of being brought between the adhesive surface and the wall. Positioning elements by which the contact element is capable of being positioned at the wall are arranged at the adhesive surface. The positioning element has a width which is variable in dependence on a spacing from the outlet opening. The width reduces at least sectionally as the spacing from the outlet opening increases and is minimal at a maximum spacing from the outlet opening. Accordingly, the adhesive surface is capable of flowing around the positioning element on the introduction between the wall and the adhesive surface.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a U.S. National stage application of International Application No. PCT/EP2014/054351, filed Mar. 6, 2014, which claims priority to EP Application No. 13160082.7, filed Mar. 20, 2013, the contents of each of which is hereby incorporated herein by reference. 
     
    
     BACKGROUND 
       [0002]    1. Field of Invention 
         [0003]    The invention relates to a fastening element for attaching to a wall. 
         [0004]    2. Background Information 
         [0005]    A fastening element for attaching to a wall is described in U.S. Pat. No. 4,822,656. The fastening element has a holder element in the form of a pin which has an external thread. An object can be fastened to the fastening element and thus to the wall via the holder element. The fastening element moreover has a contact element having an adhesive surface. An adhesive agent is applied to the adhesive surface prior to the attachment to the wall. An installation frame into which the fastening element is inserted is subsequently positioned at the wall by positioning elements in the form of adhesive strips, with there not yet being any contact between the adhesive agent and the wall. The fastening element is then brought into a press-on position within the installation frame in which contact position the adhesive surface together with the adhesive agent is pressed against the wall. The installation frame is removed and disposed of after the hardening of the adhesive agent. 
         [0006]    A fastening element for attaching to a wall is described in WO 01/81774 A1 in which no installation frame is required. It likewise has a holder element for holding an object. It has a contact element having an adhesive surface and a rear side and a filling passage which leads from the rear side of the contact element to an outlet opening in the adhesive surface of the contact element. A flowable adhesive agent can be introduced between the adhesive surface and the wall via the filling passage for attaching the fastening element to the wall. The contact element, and thus the fastening element, is positioned at the wall by a positioning element in the form of a double-sided adhesive tape before the introduction of the adhesive element. 
         [0007]    WO 01/81774 A1 does not make any statement on the design or shape of the positioning element. Trials have shown that when commercial adhesive strips in rectangular form (if the thickness of the adhesive strip is neglected) are used, an uneven distribution of the adhesive agent between the adhesive surface and the wall arises. This in turn has the result that the adhesive surface, and thus the fastening element, are not ideally fastened to the wall. 
       SUMMARY 
       [0008]    In the light of this, it is in particular the object of the invention to propose a fastening element which can be attached to a wall without the use of an installation frame and which nevertheless allows a very good adhesion to the wall. In accordance with the invention, this object is satisfied by a fastening element having the features described herein. 
         [0009]    The fastening element in accordance with the invention for attaching to a wall has a holder element for holding an object, a contact element having an adhesive surface and a rear side and a filling passage which leads from the rear side of the contact element to an outlet opening in the adhesive surface of the contact element. A flowable adhesive agent can be brought between the adhesive surface and the wall via the filling passage. The fastening element moreover has a positioning element by which the contact element can be positioned at the wall. “Positioning” is to be understood in this connection such that the fastening element is positioned and thus (pre-)fastened to the wall before the final attachment at a desired position. 
         [0010]    In accordance with the invention, the positioning element has a width which is variable in dependence on a spacing from the outlet opening. The width of the positioning element results from an extent parallel to the adhesive surface and perpendicular to a direction of flow from the outlet opening through a center of area of the positioning element. The width reduces at least sectionally as the spacing from the outlet opening increases and is minimal at a maximum spacing from the outlet opening. The width at the maximum spacing is in this respect minimal at least with respect to the section with reducing width toward the maximum spacing. It is possible that the positioning element also has a smaller width than at the maximum spacing in another section which is closer to the outlet opening. 
         [0011]    It is thus achieved that the adhesive agent can flow very easily around the positioning element on the introduction between the wall and the adhesive surface and regions do not result behind the positioning element viewed in the direction of flow into which no or comparatively little adhesive agent arrives. The embodiment of the positioning element in accordance with the invention thus makes it possible that the complete region between the adhesive surface and the wall can be filled uniformly with adhesive agent with the exception of the positioning element and thus an ideal adhesion of the fastening element to the wall is ensured. The quantity of adhesive agent which oozes out unused from the intermediate space between the adhesive surface and the wall is moreover very small due to the easy flowing around of the adhesive agent. 
         [0012]    The holder element and the contact element are manufactured from metal or plastic, for example, and are fixedly connected to one another. The connection can be established, for example, by adhesive bonding or by welding, in particular friction welding. It is also possible that the holder element and the contact element are made in one piece. This is in particular advantageous when the elements are composed of plastic. In this case, they can be manufactured using an injection molding process. 
         [0013]    A “wall” is to be understood as a surface at which an object, for example a hook, a panel or similar can be fastened. The wall is in particular designed at least regionally as planar. It is, however, possible that the wall is designed as curved. In addition, the wall can also have two or three part surfaces, in particular planar part surfaces, which are arranged at an angle with respect to one another of in particular 90°. The contact element and thus the adhesive surface then in particular have a shape corresponding to the contour of the wall. The adhesive surface can then in particular be made from a first adhesive part surface, a second adhesive part surface and possibly a third adhesive part surface which are arranged at an angle with respect to one another of 90°, for example. The adhesive part surfaces are in particular designed as planar surfaces. Slight differences between the contour of the wall and the shape of the adhesive surface can also be compensated by the adhesive agent. The wall can, for example, be part of a building, of a vehicle or of an aircraft. The wall can in particular be designed as part of an aircraft at which an inner panel is mounted by fastening elements in accordance with the invention. 
         [0014]    In the geometrical definition and description of the positioning element, a thickness of the positioning element, that is an extent perpendicular to the adhesive surface, and thus also perpendicular to the wall, is neglected. The positioning element is considered in simplified terms as a two-dimensional surface which is aligned parallel to the wall and to the adhesive surface. The positioning element thus has a center of area which is used for defining the direction of flow. The center of area can as in general be determined by geometrical considerations or by integration. It can also be determined purely mechanically by balancing a homogeneous body with the corresponding shape and constant thickness and density. With axially symmetrical surfaces having at least two axes of symmetry, the center of area lies at the point of intersection of the axes of symmetry. 
         [0015]    Reference is also made to the outlet opening in the defining of the direction of flow. In this connection, the outlet opening is only understood as its center, that is its center of area. With a circular outlet opening, this is the center of the cross-sectional surface. 
         [0016]    The named rear side of the contact element from which the filling passage leads to the outlet opening is characterized in that it is not part of the adhesive surface and is still accessible after the positioning of the fastening element at the wall. It can, but does not have to be designed as parallel to the adhesive surface. 
         [0017]    A two-component adhesive, in particular an epoxy adhesive, can be used as the adhesive agent, for example. 
         [0018]    The positioning element in particular adopts a surface portion between 3 and 20%, preferably between 5 and 10%, of the adhesive surface. A very good compromise thus results between the remaining surface which is available for the adhesive agent and thus for the permanent fastening and a holding force of the positioning element after the positioning of the fastening element to the wall and thus on the filling in of the adhesive agent. 
         [0019]    In an embodiment of the invention, the positioning element is arranged such that its center of area lies in a range from 20 to 70% of a total flow path of the adhesive agent. The regional indication in this respect is with reference to starting from the outlet opening. A particularly advantageous flowing around of the positioning element and thus a particularly good and uniform of the adhesive agent is thus made possible. A total flow path is to be understood in this respect as the path in the direction of flow from a margin of the outlet opening in the direction of the positioning element up to a margin of the adhesive surface. 
         [0020]    In an embodiment of the invention, the positioning element is arranged so that a free flow path of the adhesive which amounts to at least 20% of the total flow path of the adhesive agent results both between the outlet opening in the adhesive surface of the contact element and the positioning element and also between the positioning element and a margin of the adhesive surface of the contact element. This, on the one hand, makes it possible that the adhesive agent can distribute easily after the exiting of the outlet opening and, on the other hand, that the two part flows of the adhesive agent resulting in the flowing around of the positioning element can recombine after the positioning element and so no regions without adhesive agent arise between the adhesive surface and the wall. A particularly good and uniforni distribution of the adhesive agent is thus made possible, which results in a particularly stable fixing of the fastening element to the wall. 
         [0021]    In an embodiment of the invention, the positioning element has a length which results from an extent in the direction of flow. A ratio of length to maximum width of the positioning element is larger than 1:1. The named ratio is particularly preferably between 2 and 3. A particularly advantageous flowing around of the positioning element is thus made possible. 
         [0022]    In an embodiment of the invention, the width of the positioning element first increases starting from a minimal spacing from the outlet opening up to the reaching of a maximum width in order then to reduce again and to be minimal at the maximum spacing from the outlet opening. A particularly advantageous flowing around of the positioning element is thus made possible. 
         [0023]    In an embodiment of the invention, the positioning element has at least one axis of symmetry. A longest axis of symmetry includes an angle y of a maximum of 60°, in particular a maximum of 45°, with the direction of flow. Larger angles y would prevent a flowing around of the positioning element. 
         [0024]    The positioning element is in particular made as ellipsoid or as diamond-shaped. It can also have a shape which results from two arcs, in particular two arcs of a circle. In this connection, an arc is understood as a line curved in any desired form toward one side. These shapes allow a particularly advantageous flowing around of the positioning element. 
         [0025]    In an embodiment of the invention, the positioning element has a thickness between 0.05 and 3.00 mm, in particular between 0.1 and 0.5 mm. A correspondingly thick layer of adhesive agent can thus form between the adhesive surface and the wall, which allows a particularly good fixing of the fastening element to the wall. 
         [0026]    In an embodiment of the invention, the positioning element has a pressure sensitive adhesive. A pressure sensitive adhesive is to be understood as an adhesive which remains highly viscous and permanently sticky after application to a carrier material and can then be applied to a substrate by pressure and remains stuck there. The positioning element can, for example, be designed as a double-sided adhesive tape. The positioning element can thus be handled particularly easily. In addition, a starting material with a pressure sensitive adhesive is inexpensive and a wide selection is available on the market. The individual positioning elements can in particular only be covered by a single masking film after the attachment to the adhesive surface. A particularly simple handling is thus possible. In addition, the masking film can have a projecting tab by which the masking film can in particular also be pulled off with gloves. 
         [0027]    In an embodiment of the invention, the positioning element is designed as sprayable. The positioning element is then in particular applied to the adhesive surface in that a spray adhesive having a pressure sensitive adhesive is sprayed onto the adhesive surface. To ensure the desired shape of the positioning element, a stencil is in particular used which covers all regions of the adhesive surface except for the region intended for the positioning element. The positioning element can thus be applied very simply and fast and so inexpensively to the adhesive surface. This is in particular advantageous when not only one, but rather a plurality of positioning elements are provided. They can all be applied together in only one workstep. The positioning elements have in particular already been applied to the wall some time before the attachment of the fastening element to the wall and have been covered by a masking film. In this case, in particular only one masking film is used for all positioning elements of an adhesive surface. The fastening element can thus be prepared very fast and simply for the attaching to the wall by pulling off this one masking film. 
         [0028]    In an embodiment of the invention, the fastening element has a plurality of positioning elements which are in particular distributed uniformly around the outlet opening. A secure positioning of the fastening element and also a uniform distribution of the adhesive agent is thus made possible. 
         [0029]    In an embodiment of the invention, the holder element has a predominantly hollow-cylindrical shape and forms a first part of the filling passage. A particularly simple structure of the fastening element is thus made possible. To hold an object, the holder element in particular has an external thread which can cooperate with a corresponding internal thread of the object. Other holder types are, however, also possible such as a snap-in connection or a click connection. 
         [0030]    In an embodiment of the invention, the contact element is designed as a circular disk through whose central axis a second part of the filling passage extends which ends at the outlet opening. This allows a simple and inexpensive structure of the fastening element. In addition, this shape makes it possible that a quantity of adhesive agent which is as small as possible is sufficient to fill up the total region between the adhesive surface and the wall. This is in particular achieved in that the total flow path is the same in all directions. The contact element in particular has a diameter of 2 to 6 cm. Smaller or larger diameters are, however, also possible depending on the application case. 
         [0031]    It is also possible that the contact element does not have an exactly circular outer contour, but is rather slightly “flattened” in the regions in which positioning elements are arranged. Since the adhesive agent is slowed down by the positioning element on the introduction between the adhesive surface and the wall, it can thus be achieved that the adhesive agent reaches the margin at the total outer contour without passing over the margin at any point. It can thus be achieved that a minimal quantity of adhesive agent is sufficient to fill up the total region between the adhesive surface and the wall. 
         [0032]    Further advantages, features and details of the invention result with reference to the following description of embodiments and with reference to drawings in which elements which are the same or have the same function are provided with identical reference numerals. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0033]      FIG. 1  is a fastening element positioned at a wall; 
           [0034]      FIG. 2  is a plan view of an adhesive surface with positioning elements; 
           [0035]      FIG. 3  is a plan view of a second embodiment of an adhesive surface with positioning elements: 
           [0036]      FIG. 4  is a plan view of a third embodiment of an adhesive surface with positioning elements: 
           [0037]      FIG. 5  is a plan view of a fourth embodiment of an adhesive surface with positioning elements; and 
           [0038]      FIG. 6  is a plan view of a fifth embodiment of an adhesive surface with positioning elements. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0039]    In accordance with  FIG. 1 , a fastening element  10  positioned at a planar wall  11  has a holder element  12 . The holder element  12  has a predominantly hollow-cylindrical shape and has at its peripheral surface an external thread  13  which can cooperate with an internal thread of an object, not shown. The object which is not shown can, for example, be designed as a hook which can be screwed onto the holder element  12  and can thus be held at the wall  11  via the fastening element  10 . 
         [0040]    The fastening element  10  is fixedly connected to a contact element  14  by a weld connection, not shown. The two elements are produced from metal in this embodiment. 
         [0041]    The contact element  14  is designed as a circular disk through whose central axis  15  a second part  16  of a filling passage  17  extends which ends at an outlet opening  18 . The holder element  12  is arranged on the contact element  14  such that it is arranged coaxial to the central axis  15  of the contact element  14 . A first part  19  of the filling passage  17  extends within the holder element  12  and ends with a filling opening  20 . 
         [0042]    The contact element  14  has a planar adhesive surface  21  which is aligned toward the wall  11  and includes the outlet opening  18  of the filling passage  17 . The holder element  12  is arranged on the rear side  22  of the contact element  14  disposed opposite the adhesive surface  21 . The fastening element  10  is positioned at the wall  11  and thus prefastened by a total of four positioning elements  23   a ,  23   b ,  23   c ,  23   d , of which only two positioning elements  23   b  and  23   d  can be seen in  FIG. 1 . The positioning elements  23   b ,  23   d  are designed as double-sided adhesive tapes whose form will be looked at in more detail in the description of  FIG. 2 . The positioning elements  23   a ,  23   b ,  23   c ,  23   d  thus contain a pressure-sensitive adhesive and have a thickness of approximately 0.8 mm so that the adhesive surface  21  of the contact element  14  and the wall  11  have a spacing of approximately 0.8 mm. 
         [0043]    A flowable adhesive agent, not shown, can be introduced between the adhesive surface  21  and the wall  11  for the final attachment of the fastening element  10  to the wall  11 . The adhesive agent dries and then hardens and the fastening means or element  10  is thus fixedly connected to the wall  11 . 
         [0044]      FIG. 2  shows the fastening element  10  in a view from the wall  11 , that is a plan view of the adhesive surface  21  of the contact element  14  designed as cylindrical or disk-shaped with the exception of the second part  16  of the filling passage  17 . The representation is in this respect not exactly to scale. The filling passage  17  is designed as cylindrical and ends with the circular outlet opening  18 . The outlet opening  18  is arranged so that its center  24  lies on the central axis  15  of the contact element  14 . The four positioning elements  23   a ,  23   b ,  23   c ,  23   d  are each designed as identical ellipses and are distributed uniformly around the outlet opening  18 . The ellipsoid positioning elements  23   a ,  23   b ,  23   c ,  23   d  each have a long axis of symmetry and a short axis of symmetry of which only a respective one long axis of symmetry  26   a  and one short axis of symmetry  27   a  of the positioning element  23   a  are provided with reference numerals. The two axes of symmetry each intersect at a center of area  25   a ,  25   b ,  25   c ,  25   d  of the positioning elements  23   a ,  23   b ,  23   c ,  23   d . A respective direction of flow  28   a ,  28   b ,  28   c ,  28   d  which extends, starting from the center  24  of the outlet opening  18 , through the centers of area  25   a ,  25   b ,  25   c ,  25   d  of the positioning elements  23   a ,  23   b ,  23   c ,  23   d  thus results for each positioning element  23   a ,  23   b ,  23   c ,  23   d . The positioning elements  23   a ,  23   b ,  23   c ,  23   d  are aligned so that the respective long axis of symmetry  26   a , and thus the longest axis of symmetry, is aligned along the direction of flow  28   a ,  28   b ,  28   c ,  28   d . A respective angle of 90° results between two adjacent directions of flow  28   a ,  28   b ,  28   c ,  28   d  due to the uniform distribution of the positioning elements  23   a ,  23   b ,  23   c ,  23   d  around the outlet opening  18 . 
         [0045]    Since all the positioning elements  23   a ,  23   b ,  23   c ,  23   d  have an identical shape and are also aligned identically with respect their respective directions of flow  28   a ,  28   b ,  28   c ,  28   d , only the positioning element  23   b  will be looked at in the following, with the statements also applying to the positioning elements  23   a ,  23   c ,  23   d.    
         [0046]    The positioning element  23   b  has a width which is variable perpendicular to the direction of flow  28 , and thus parallel to the short axis of symmetry, and which depends on a spacing from the outlet opening  18  or more exactly on the spacing from the center  24  of the outlet opening  18 . Three widths b 1 , b 2 , b 3  are drawn by way of example, with the first width b 1  lying, viewed from the outlet opening  18 , before the short axis of symmetry, the second width b 2  on it and the third width b 3  behind it. The width first increases constantly as the spacing from the outlet opening  18  increases and reaches the maximum width b 2  at the short axis of symmetry. Subsequently, the width continuously reduces and reaches a minimal width of quasi zero at a maximum spacing  29 . The positioning element  23   b  furthermore has a length  1  which results from an extent of the positioning element  23   b  in the direction of flow  28   b . A ratio of length  1  to the maximum width b 2  of the positioning element  23   b  is in this respect approximately 3 and thus larger than 1:1: 
         [0047]    The adhesive agent is supplied via the outlet opening  18 . It then flows radially outwardly up to a margin  30  of the adhesive surface  21 . A total flow path  31  of the adhesive path thus results which starts at a margin  32  of the outlet opening  18  and ends at the margin  30  of the adhesive surface  21 . Since both the adhesive surface  21  and the outlet opening  18  are circular, the total flow path  31  is of equal length in all directions. 
         [0048]    The positioning element  23   b  is arranged such that its center of area  25   b  has a spacing  33  from the margin  32  of the outlet opening  18  which corresponds to approximately 62% of the total flow path  31 . In addition, a first flow path  34  of the adhesive agent results between the margin  32  of the outlet opening  18  and the positioning element  23   b  which corresponds to approximately 29% of the total flow path  31 . The first free flow path  34  simultaneously represents a minimal spacing of the positioning element  23   b  from the outlet opening  18 . In addition, a second free flow path  35  of the adhesive agent results between the positioning element  23   b  and the margin  30  of the adhesive surface which likewise corresponds to approximately 29% of the total flow path  31 . 
         [0049]    In the second embodiment in accordance with  FIG. 3 , an adhesive surface  121  and an outlet opening  118  are identical to the embodiment in accordance with  FIGS. 1 and 2 . Four positioning elements  123   a ,  123   b ,  123   c ,  123   d  are arranged uniformly around the outlet opening  118 . The positioning elements  123   a ,  123   b ,  123   c ,  123   d  are sprayed on in this embodiment and have a thickness of approximately 0.3 mm. 
         [0050]    The ellipsoid positioning elements  123   a ,  123   b ,  123   c ,  123   d  each have a long axis of symmetry and a short axis of symmetry of which only a respective one long axis of symmetry  126   a  and one short axis of symmetry  127   a  of the positioning element  123   a  are provided with reference numerals. The two axes of symmetry each intersect at a center of area  125   a ,  125   b ,  125   c ,  125   d  of the positioning elements  123   a ,  123   d ,  123   c ,  123   d . A respective direction of flow  128   a ,  128   b ,  128   c ,  128   d  thus results for each positioning element  123   a ,  121 ,  123   c ,  123   d . The positioning elements  123   a ,  121 ,  123   c ,  123   d  are aligned so that the respective long axis of symmetry  126   a , and thus the longest axis of symmetry, is aligned along the direction of flow  128   a ,  128   b ,  128   c ,  128   d.    
         [0051]    Since all the positioning elements  123   a ,  123   b ,  123   c ,  123   d  have an identical shape and are also aligned identically with respect their respective directions of flow  128   a ,  128   b ,  128   c ,  128   d , only the positioning element  121  will be looked at in the following, with the statements also applying to the positioning elements  123   a ,  123   c ,  123   d.    
         [0052]    The positioning element  123   b  has a width which is variable perpendicular to the direction of flow  128   b  and thus parallel to the short axis of symmetry and which depends on a spacing from the outlet opening  118 . The width first increases constantly as the spacing from the outlet opening  118  increases and reaches a maximum width b 12  at the short axis of symmetry. Subsequently, the width continuously reduces and reaches a minimal width of quasi 0 at a maximum spacing. The positioning element  123   b  furthermore has a length  11  which results from an extent of the positioning element  123   b  in the direction of flow  128   b . A ratio of length  11  to the maximum width b 12  of the positioning element  123   b  is in this respect approximately 3.5 and thus larger than 1:1. 
         [0053]    The positioning element  123   b  is arranged such that its center of area  125   b  has a spacing from a margin  132  of the outlet opening  118  which corresponds to approximately 50% of the total flow path. In addition, a first flow path of the adhesive agent results between the margin  132  of the outlet opening  118  and the positioning element  1233  which corresponds to approximately 21% of the total flow path. The first free flow path simultaneously represents a minimal spacing of the positioning element  123   b  from the outlet opening  118 . In addition, a second free flow path of the adhesive agent  121  results between the positioning element  123   b  and a margin  130  of the adhesive surface  121  which likewise corresponds to approximately 21% of the total flow path. 
         [0054]    In the third embodiment in accordance with  FIG. 4 , an adhesive surface  221  and an outlet opening  218  are identical to the embodiment in accordance with  FIGS. 1 and 2 . Four positioning elements  223   a ,  223   b ,  223   c ,  223   d  are arranged uniformly around the outlet opening  218 . 
         [0055]    The positioning elements  223   a ,  223   b ,  223   c ,  223   d  have a shape which results from two arcs of a circle. They each have a long axis of symmetry and a short axis of symmetry of which only a respective one long axis of symmetry  226   a  and one short axis of symmetry  227   a  of the positioning element  223   a  are provided with reference numerals. The two axes of symmetry each intersect at a center of area  225   a ,  225   b ,  225   c ,  225   d  of the positioning elements  223   a ,  223   b ,  223   c ,  223   d . A respective direction of flow  228   a ,  228   b ,  228   c ,  228   d  thus results for each positioning element  223   a ,  223   b ,  223   c ,  223   d . The positioning elements  223   a ,  223   b ,  223   c ,  223   d  are aligned so that the respective long axis of symmetry  226   a , and thus the longest axis of symmetry, is aligned along the direction of flow  228   a ,  228   b ,  228   c ,  228   d.    
         [0056]    Since all the positioning elements  223   a ,  223   b ,  223   c ,  223   d  have an identical shape and are also aligned identically with respect their respective directions of flow  218   a ,  228   b ,  228   c ,  228   d , only the positioning element  223   b  will be looked at in the following, with the statements also applying to the positioning elements  223   a ,  223   c ,  223   d.    
         [0057]    The positioning element  223   b  has a width which is variable perpendicular to the direction of flow  228   b  and thus parallel to the short axis of symmetry and which depends on a spacing from the outlet opening  218 . The width first increases constantly as the spacing from the outlet opening  218  increases and reaches a maximum width b 22  at the short axis of symmetry. Subsequently, the width continuously reduces and reaches a minimal width of quasi 0 at a maximum spacing. The positioning element  223   b  furthermore has a length  12  which results from an extent of the positioning element  223   b  in the direction of flow  228   b . A ratio of length  12  to the maximum width b 22  of the positioning element  223   b  is in this respect approximately 2.8 and thus larger than 1:1. 
         [0058]    The positioning element  223   b  is arranged such that its center of area  225   a  has a spacing from a margin  232  of the outlet opening  218  which corresponds to approximately 50% of the total flow path. In addition, a first flow path of the adhesive agent results between the margin  232  of the outlet opening  218  and the positioning element  223   b  which corresponds to approximately 21%% of the total flow path. The first free flow path simultaneously represents a minimal spacing of the positioning element  223   b  from the outlet opening  218 . In addition, a second free flow path of the adhesive agent results between the positioning element  223   b  and a margin  230  of the adhesive surface  221  which likewise corresponds to approximately 21% of the total flow path. 
         [0059]    The third embodiment in accordance with  FIG. 5  differs from the embodiment in accordance with  FIGS. 1 and 2  only in that the ellipsoid positioning elements  323   a ,  323   b ,  323   c ,  323   d  are rotated clockwise by a respective angle y of 15° about their respective centers of area  323   a ,  323   b ,  323   c ,  323   d . A longest axis of symmetry  326   b  and the direction of flow  318   b  thus include an angle y of 15°. 
         [0060]    The fourth embodiment in accordance with  FIG. 6  differs from the embodiment in accordance with  FIGS. 1 and 2  only in that the positioning elements  423   a ,  423   b ,  423   c ,  423   d  are designed as half-ellipses which only start at the short axis of symmetry of the associated complete ellipse.