Abstract:
The invention relates to a tongue connection, in particular for fixing an air vent on a wall in a passenger compartment, on a basic body which is to be arranged in a releasable manner on a border of a wall opening by way of at least two tongues which project from the basic body, the tongues engaging, along the opening border, in the opening and restricting movement of the body in the direction of the opening plane. There is provided on at least one tongue a (radial) protrusion which projects outward in the direction of the opening border, cuts into the opening border when the basic body is installed on the wall, and prevents movement of the basic body in the opening plane by producing a form fit in relation to the opening border.

Description:
FIELD AND BACKGROUND OF THE INVENTION 
     The invention relates to a tongue connection, in particular for fixing an air vent on a wall in a passenger compartment. 
     Such a tongue connection is known from EP 0271 706 B1 and relates to a vent for supplying air to windows. Said document discloses an approximately box-like vent frame on which four latching tongues are integrally formed. The vent frame can be secured in through-passages of a corresponding bodywork part by means of said latching tongues, the latter engaging behind an opening border of the wall and preventing movement of the vent frame in the direction perpendicular to an opening plane. 
     A further tongue connection of the basic type can be found in DE 40 16 026 C2, this relating to a device for supplying air to the interior of a vehicle. This document outlines a housing which has arranged on its front side, which is designed as a flange, clip elements which serve for clipping the entire air vent in a cutout of a wall. These clip elements too engage behind an opening border of the wall and thus ensure that the housing is secured in the direction perpendicular to an opening plane of the cutout. 
     SUMMARY OF THE INVENTION 
     The object of the invention is to provide a tongue connection which is of the above type and which allows improved fixing of a basic body on a border of a wall opening. 
     In the case of the tongue connection according to the invention, it is provided on at least one tongue a (radial) protrusion which projects outward in the direction of the opening border, cuts into the opening border, when the basic body is installed on the wall, and prevents movement of the basic body in the opening plane by producing a form fit in relation to the opening border. As a result, in addition to the task of restricting the movement of the basic body in the direction of the opening plane, the tongue can also easily assume the task of securing the basic body in the direction of the opening plane without a separate component being necessary. For example, a rotationally symmetrical basic body can thereby be secured against a rotary movement within a wall opening adapted to it. It should also be conceivable for a basic body with four or more sides to be secured in a specific position, for example, against linear movement within an elongate slot opening. 
     A further advantage is that the form-fitting connection can easily be produced, for example by subjecting the basic body to a force in the direction approximately perpendicular to the opening plane, it also being easily possible for the basic body to be removed subsequently. 
     Advantageous embodiments of the tongue connection according to the invention along with expedient developments of the invention are specified in the subclaims. 
     Thus, it has proven particularly favorable if the tongue can be braced radially with the opening border, as a result of which, in addition to being secured in the direction of the opening plane, the basic body can also be fixed by the tongue in the direction approximately perpendicular to the opening plane. 
     This additional securing of the basic body may also be achieved in that at least one tongue has an additional latching nose by means of which the basic body can be fixed on the wall approximately in the direction perpendicular to the opening plane. 
     If the basic body is of annular design, and if four tongues, offset by in each case approximately 90° with respect to one another, are integrally formed on it, then the basic body may be secured in position, and against rotation, in the direction of the opening plane particularly firmly in a wall opening of circular design. If, in this case, all four tongues each have a radial protrusion, this results in particularly stable securing against rotation within the circular wall opening. 
     It has also proven particularly favorable, in a further configuration of the invention, if the vertically extending radial protrusion is designed in the manner of a cutting edge at least in certain areas, this making it possible for the protrusion to cut easily in the opening border. The cutting-in operation functions particularly well, in particular, when the material of the opening border is softer than that of the protrusion. 
     In addition, the cutting-in operation may be improved in that the cutting portion of the respective radial protrusion is of filetooth-like or sawtooth-like design, as a result of which material can easily be removed at the opening border. 
     It is particularly advantageous for the four tongues to be of resilient design and each to be provided with a latching nose which projects radially beyond a top portion located above, this making it possible to achieve particularly stable securing of the basic body in the direction perpendicular to the opening plane. A further advantage of this configuration is that it is possible for the radial protrusion, during installation, to cut into the opening border of the wall not just in the approximately vertical direction in relation to the opening plane, by an installation force, but also in the horizontal direction, by the spring force of the tongue. 
     If, in this case, in each case one installation lug, which is directed inward in the direction of the center axis of the annular basic body, is integrally formed on the four resilient tongues, then the basic body can easily be centered on the wall opening and can easily be installed by the basic body being subjected to a relatively small force in the direction of the wall opening. 
     Finally, it has proven particularly advantageous for an air vent with an annular base body, a rotatable rotary base and a spherical vent to be arranged in the wall opening with the aid of the tongue connection, it being the case that the air vent can be installed particularly easily and is of an attractive and expedient configuration. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Further advantages, features and details of the invention can be gathered from the following description of a preferred exemplary embodiment and with reference to the drawings, in which: 
     FIG. 1 shows a side view of an air vent with a basic body and tongues, projecting from the latter, of a tongue connection according to the invention; 
     FIG. 2 shows an enlarged illustration of one of the projecting tongues of the tongue connection according to the invention in accordance with the detail II in FIG. 1; 
     FIG. 3 shows a lateral sectional view of the projecting tongue of the tongue connection according to the invention along section line III—III in FIG. 2; 
     FIG. 4 shows a sectional view of a wall with a wall opening, illustrated on a reduced scale, on the underside of which it is possible to see four incisions introduced by the tongues; 
     FIG. 5 shows a bottom view of the wall opening with the incisions according to FIG. 4; and 
     FIG. 6 shows a section view of a further wall with a wall opening (illustrated on a reduced scale), on the underside of which it is possible to see the incisions introduced by the tongues. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1 shows an air vent  10  which has an annular basic body  11  with a center axis MG. The annular basic body  11  is illustrated in cut-away form to the left of a cut-off line and—as can be seen in the cut-away portion—has an approximately L-shaped cross-section with a side portion  12  and a bottom portion  13 . The basic body  11  receives a rotary base  14 , which can be rotated about the center axis MG and is adapted to the basic body  11  in the region of the side portion  12  and of the bottom portion  13  by way of a base ring  15 . In this case, the rotary base  14  can be adjusted in latching steps in relation to the basic body  11  by means of a latching device (not shown) or by latching teeth. The basic body  11  may—as is shown here—have a circumferential protrusion  23 , by means of which the rotary base  14  is received in the basic body  11  in an axially secured manner. Integrally formed on a top end surface  16  of the base ring  15  are two upwardly projecting base lugs  17 , which are designed essentially in the form of segments of a circle. The two base lugs  17 , which are arranged diametrically in relation to the center axis MG, receive a spherical vent  18  such that it can be pivoted about a pivot axis SD. The pivot axis SD preferably runs in the center of the base lugs  17  and approximately normal to the center axis MG and parallel to a bottom surface  19  of the basic body  11 . Provided between the base lugs  17  and the spherical vent  18  are latching teeth or latching devices (not illustrated) by means of which the spherical vent  18  can be pivoted in latching steps, out of the central position shown, through an angle α of approximately 40° in the upward direction and through an angle β of approximately 25° in the downward direction. The spherical vent  18  is designed approximately in the form of a segment of a sphere and has air-outlet openings  20 , which extend approximately between the base lugs  17  and are each bounded in the upward and downward directions by directing walls  21  which are fastened on an outer wall  22  of the spherical vent  18  and are provided for the directed distribution of the air emerging into the passenger compartment, the spherical vent  18  being designed to be open at its bottom end for the purpose of letting in the air. The directing walls  21  are adapted in shape to the outer contour of the spherical vent  18 , with the result that the latter gives a spherical impression overall. Integrally formed on the bottom surface  19  of the annular basic body  11  are four tongues  24  which project downward from said basic body, are integrally formed so as to be offset in each case by 90° with respect to one another, and have the same radial spacing in each case in relation to the center axis MG. 
     FIGS. 2 and 3 illustrate one of the projecting tongues  24 , in accordance with detail II in FIG. 1, respectively in a front view (FIG. 2) and in a lateral sectional view (FIG. 3) along section line III—III in FIG.  2 . The tongue  24  is integrally formed on the bottom portion  13  of the basic body  11  by way of a top portion  25 , which has an outwardly projecting radial protrusion  26 . The radial protrusion  26  runs vertically and comprises a bottom web portion  27  and a cutting portion  28  arranged above the latter. The web portion  27  is of constant width and thickness over its entire height and merges into the cutting portion  28  at a transition edge  29 . The cutting portion  28  has a cutting edge  30  which extends from the transition edge  29  to a top point  31  of the radial protrusion  26 , the cutting portion  28  tapering both in width and in thickness from the transition edge  29  and running to a point in the direction of the top point  31 . This forms, in the region of the cutting portion  28 , a left-hand cutting surface  42  and a right-hand cutting surface  43 , which are approximately triangular and are of smooth design in this case. However, it should also be possible for the cutting surfaces  42 ,  43  to be provided with fileteeth, in order to allow the radial protrusion  26  to cut in more easily. It is also possible for the cutting edge  30  to be provided with sawteeth for the purpose of improving the cutting action. 
     At the bottom end of the top portion  25 , the tongue  24  comprises a latching nose  32 , which projects beyond the top portion  25  in the radially outward direction. The latching nose  32  terminates, on the outside, approximately flush with the web portion  27  of the radial protrusion  26  and has an outwardly and downwardly inclined latching surface  39 . 
     The bottom end of the tongue  24  forms an installation lug  33 , which is formed integrally with the top portion  25  and the latching nose  32 . The installation lug  33  is reduced somewhat in width in relation to the top portion  25  and—as can be seen in FIG.  3 —is bent inward in the direction of the axis of rotation MG of the basic body  11 . 
     FIG. 4 illustrates a sectional view of a wall  34  with a somewhat sunken bead  35 , in which the wall  34  has an opening  36  passing through it. The wall opening  36  is of circular design and is adapted in diameter approximately to the outer sides of the top portions  25  of the tongues  24 . The wall opening  36  is introduced into the wall  34  approximately perpendicularly, a border  37  of the wall opening  36  likewise extending approximately perpendicularly to the wall  34 . On the top side of the wall  34 , an opening plane ÖE extends in the bead  35 , the bottom surface  19  of the basic body  11  coming to rest thereon when the air vent  10  is installed. 
     On the underside of the wall  34 , it is possible to see in the opening border  37 —and this can also be seen in FIG.  5 —for incisions  38  which are offset by in each case approximately 90° with respect to one another and have been cut into the opening border  37  by the radial protrusions of the installed, and subsequently removed, air vent  10 . The incisions  38  thus correspond in shape to the cutting portion  28  of the tongues  24  and—as can be seen in FIG.  4 —in longitudinal section are cut in approximately in the form of triangles on the underside of the opening border  37 . FIG. 4 shows that the cross-section of the incisions  38  is also approximately triangular. 
     The opening border  37  illustrated in FIG. 6 widens outward in the direction of the underside of the wall  34 , with the result that the incisions  38  introduced into the opening border  37  by the cutting portions  28  of the tongues  24  run approximately over the entire height of the opening border  37 , and approximately parallel to the latter. The cross-section of the incisions  38 , once again, is approximately triangular. 
     The air vent is installed as follows: 
     Since the wall opening  36  corresponds in diameter approximately to the diameter of the tongues  24  on the outside of their top portion  25 , the air vent  10  can be centered on the top side of the wall opening  36  by being placed in position by way of the inwardly directed installation lugs  33  of the tongues  24 . If the air vent  10  is then forced vertically in the. direction of the wall  34 , then the resilient tongues  24  slide downward along the top side of the border  37  of the wall opening  36 , the resilient tongues  24  moving inward toward the center axis MG of the basic body  11 . Once the tongues  24 , following further movement of the air vent  10  in the downward direction, have passed the bottom end of the opening border  37  by way of the latching surfaces  39  and the web portions  27  of the radial protrusions  26 , the resilient tongues  24  are *moved outward again and latch in their installation position, as a result of which the basic body  11  is secured perpendicularly to the opening plane ÖE. In this case, the bottom surface  19  of the basic body  11  comes to rest flush on the top surface of the wall  24 , which is determined by the opening plane ÖE. By virtue of the tongues  24  moving in the downward and outward directions, the radial protrusions  26  cut into the border  37  of the wall opening  36  by way of their cutting portion  28 , with the result that the basic body  11  is braced radially and secured against rotation by a form fit between the radial protrusions  26  and the incisions  38 . In the exemplary embodiment shown here, the radial protrusions  26  cut into the opening border  37  of the wall  34  both in the approximately vertical direction in relation to the opening plane ÖE, by an installation force, and in the horizontal direction, by the spring force of the tongue  24 . It is thus possible for the incisions  38  to be cut in by the radial protrusions  26  only on the underside of the opening border  37 —as in FIG.  4 —or parallel to an oblique opening border  37 —as in FIG.  6 . It would likewise be conceivable for the radial protrusions  26  to cut into the opening border  37  of the wall  34  either only, by an installation force, in approximately the vertical direction in relation to the opening plane ÖE or in the horizontal direction, by the spring force of the tongue  24 . In order to allow the incisions  38  to be cut into the opening border  37  of the wall  34 , it is also possible for the tongues  24  to be produced from a correspondingly harder material than the wall  34 . A basic body  11  formed integrally with the tongues  24  must additionally be formed from a material which ensures the resilient properties of the tongues  24 , for example from a relatively brittle polypropylene. An impact-resistant polypropylene is an example of the suitable basic material for the wall  34  in this combination.