Abstract:
The invention relates to a device for attaching two add-on parts ( 36, 37 ) to a carrier part ( 35 ), said device having an outer clamp ( 1 ) and an inner clamp ( 11 ) that arrests any movement of the outer clamp ( 1 ), said clamps being insertable, in an interlocked arrangement, into a single insertion opening configured in the carrier part ( 35 ) so as to hold not only an add-on part ( 37 ) that is movable relative to the carrier part ( 35 ), but also the additional add-on part ( 36 ), on the carrier part ( 35 ) with a high extraction force for each.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a U.S. National Phase Patent Application based on International Application Serial No. PCT/EP2008/006679 filed Aug. 14, 2008, the disclosure of which is hereby explicitly incorporated by reference herein. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a device for attaching two add-on parts to a carrier part. 
     2. Description of the Related Art 
     In conventional devices for attaching two add-on parts to a carrier part, each add-on part normally has a separate attaching element, each of which is to be anchored in a respective opening provided for this purpose in the carrier part. This is disadvantageous, however, for example when space is limited or when the carrier parts in question are fairly heavily loaded structurally. 
     SUMMARY OF THE INVENTION 
     The present invention provides a device for attaching two add-on parts to a carrier part by which two add-on parts can be attached to a carrier part with economy of space, with relatively little weakening of the carrier part, and relatively easily. 
     By virtue of the fact that the device according to the invention comprises an outer clamp configured with two shank arms and an inner clamp that is disposed between the outer clamp, both of which clamps enter into engagement with the carrier part, via the rear engagement sections and via the bearing sections, respectively, and each of which secures a respective add-on part to the carrier part by means of, respectively, the hold-down tabs and the on-lying tabs, only one insertion opening need be provided in the carrier part for the entire inventive device. The resulting attachment of the two add-on parts is space-saving, structurally minimally weakening, and, due to the inventive configuration of the outer and inner clamps, very easy to perform manually. 
     In one form thereof, the present invention provides a device for attaching two add-on parts to a carrier part, including an outer clamp that is fabricated from a sheet metal strip as a one-piece stamped and bent part and has two shank arms disposed opposite each other and connected to each other at one end, and, at the other, free end of each shank arm, a laterally protruding hold-down tab, wherein each shank arm of the outer clamp has a rear engagement section that extends from a connection end toward the other shank arm and is disposed a first distance from the hold-down tab; and including an inner clamp disposed between the shank arms of the outer clamp and having two oppositely disposed side legs that are connected to each other at one end, characterized in that the inner clamp is fabricated from a sheet metal strip as a one-piece stamped and bent part; in that a laterally protruding on-lying tab is configured at the other end of each side leg of the inner clamp; in that the inner clamp enters into engagement with the carrier part via bearing sections configured each on a respective rear engagement tongue; in that each side leg of the inner clamp has a respective bearing section which extends from a connecting end toward the other side leg and which is a second distance from the on-lying tabs that is greater than the first distance of the rear engagement sections from the hold-down tabs of the outer clamp; and in that, on the inner clamp, each side leg includes, on the side of the bearing section remote from the bearing tab, a stop dog that extends obliquely outward by its free end. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above mentioned and other features and objects of this invention, and the manner of attaining them, will become more apparent and the invention itself will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein: 
         FIG. 1  is a perspective view of an outer clamp as per an exemplary embodiment of a device according to the invention; 
         FIG. 2  is a perspective view of an inner clamp as per the described exemplary embodiment of a device according to the invention; 
         FIG. 3  is a first longitudinal section of the outer clamp according to  FIG. 1  and the inner clamp according to  FIG. 2  as per the described exemplary embodiment of a device according to the invention in an assembled arrangement, in engagement with a carrier part and with two add-on parts; 
         FIG. 4  is a second longitudinal section of the arrangement according to  FIG. 3 , taken at right angles to the longitudinal section of  FIG. 3 ; and 
         FIG. 5  is a side view of the exemplary embodiment according to  FIGS. 1 to 4 , with an inner clamp partially withdrawn from the outer clamp. 
     
    
    
     Corresponding reference characters indicate corresponding parts throughout the several views. Although the exemplifications set out herein illustrate embodiments of the invention, in several forms, the embodiments disclosed below are not intended to be exhaustive or to be construed as limiting the scope of the invention to the precise forms disclosed invention to the precise form disclosed. 
     DETAILED DESCRIPTION 
       FIG. 1  is a perspective view of an outer clamp  1  of an exemplary embodiment of a device according to the invention. Said outer clamp  1  is fabricated from a sheet metal strip as a one-piece stamped and bent part, and has a planar bottom section  2  with a square or rectangular base area. Formed on two mutually opposite edge sides of bottom section  2  are shank arms  3 ,  4 , which are inclined with respect to each other and which initially diverge with increasing distance from bottom section  2 , and each of which has a rear engagement section  5 ,  6  in its respective end region remote from bottom section  2 . The rear engagement section  5 ,  6  of each shank arm  3 ,  4  is bent inward and extends from an outward-lying connecting end away from bottom section  2  and toward the respective opposite shank arm  3 ,  4 . 
     Formed at the facing ends of the rear engagement sections  5 ,  6  are respective bearing sections  7 ,  8 , which in turn are connected, each at its edge side directed away from rear engagement section  5 ,  6 , to a respective hold-down tab  9 ,  10 . The hold-down tabs  9 ,  10  each extend outward and protrude laterally beyond the respective shank arm  3 ,  4 . To give the outer clamp  1  a certain elasticity in the longitudinal direction, i.e., in the direction of the shank arms  3 ,  4 , the hold-down tabs  9 ,  10  are configured as S-shaped, with the outer bend, i.e., the one farthest from the particular bearing section  7 ,  8  in the longitudinal direction of the outer clamp  1 , disposed closer to the bottom section  2  than the inner bend, i.e., the one close to the particular bearing section  7 ,  8 . In addition, the dimensions of the bearing sections  7 ,  8  and the dimensions of the hold-down tabs  9 ,  10  are so adapted to one another that the outer bends of the hold-down tabs  9 ,  10  are disposed a first distance from the rear engagement sections  5 ,  6  in the longitudinal direction of the outer clamp  1 . It can also be observed from  FIG. 1  that the hold-down tabs  10  are wider than the shank arms  3 ,  4 . 
       FIG. 2  is a perspective view of an inner clamp  11  of the described exemplary embodiment of a device according to the invention. Like outer clamp  1 , inner clamp  11  is fabricated from a sheet metal strip as a one-piece stamped and bent part, and has a planar foot section  12  with a square or rectangular base area, the dimensions of the foot section  12  of inner clamp  11 , for purposes of compact construction, being approximately equal to those of the bottom section  2  of outer clamp  1 . Configured on mutually opposite edge sides of foot section  12  are side legs  13 ,  14 , which extend from a bulged section  15 ,  16  immediately adjacent foot section  12  and are disposed approximately at right angles to foot section  12 , thus being oriented substantially parallel to each other. At the ends remote from foot section  12 , side legs  13 ,  14  approach each other in their respective head sections  17 ,  18  via an inwardly directed bend  19 ,  20  and are connected to each other via respective side links  21 ,  22 , which are configured on each side leg  13 ,  14  and embrace the respective other side leg  13 ,  14 . Each of the side links  21 ,  22  attaches to a respective interlock web  211 ,  221  that is configured on the respective opposite head section  17 ,  18  and extends outward within the plane of the head sections  17 ,  18 . The side legs  13 ,  14  are thereby solidly connected to each other in the region of the head sections  17 ,  18  and are locked against any movement toward or away from each other. 
     Formed on each side leg  13 ,  14 , on the side of each head section  17 ,  18  facing away from foot section  12 , is a respective laterally outwardly projecting on-lying tab  23 ,  24  is oriented approximately at right angles to the side legs  13 ,  14  and parallel to the foot section  12 . The width of the on-lying tabs  23 ,  24  is substantially the same as that of the side legs  13 ,  14 . 
     It will also be noted from  FIG. 2  that each side leg  13 ,  14  has in its bulged section  15 ,  16  a respective stop dog  25 ,  26  that is canted obliquely outward away from foot section  12  and whose end pointing away from foot section  12  protrudes laterally outward beyond the respective side leg  13 ,  14 . Configured on each side leg  13 ,  14  between the bulged section  15 ,  16  and the bend  19 ,  20  is a rear engagement tongue  27 ,  28 , which is connected by its end proximate the respective bulged section  15 ,  16  to the respective side leg  13 ,  14 . From this connection region, an adjusting section  29 ,  30  of each rear engagement tongue  27 ,  28  extends obliquely outward away from foot section  12 . Joined to the end of each adjusting section  29 ,  30  remote from foot section  12  is a bearing section  31 ,  32 , which extends from an outwardly disposed connecting end inward toward the respective head section  17 ,  18 , and is set at an oblique angle. Finally, each rear engagement tongue  28 ,  29  has at its free end an end section  33 ,  34  that is oriented approximately parallel to the longitudinal direction of the inner clamp  11 . 
     The bearing sections  30 ,  31  and the on-lying tabs  23 ,  24  are a second distance apart that is greater than the first distance between the rear engagement sections  5 ,  6  and the hold-down tabs  9 ,  10  of outer clamp  1 . 
       FIG. 3  represents a first longitudinal section of the outer clamp  1  according to  FIG. 1  and the inner clamp  11  according to  FIG. 2 , as per the described exemplary embodiment, in an arrangement where they are inserted one inside the other in an installed situation, in which a carrier part  35 , for example in the form of an autobody panel, is connected to a fabric mat  36  of an airbag assembly, as a first add-on part, and to a mounting housing  37 , configured as the “retainer” of the airbag assembly, as a second add-on part. As can be seen from  FIG. 3 , the hold-down tabs  9 ,  10  of outer clamp  1  bear against the fabric mat  36 , while the rear engagement sections  5 ,  6  of the outer clamp  1  are engaged, in their inner edge regions, with the rim of an insertion opening  38  formed in the carrier part  35 . The inclination of the rear engagement sections  5 ,  6 , together with the elasticity afforded by the curved hold-down tabs  9 ,  10 , act to bring about tolerance compensation with respect to the thickness of the carrier part  35  and/or of the first add-on part, here in the form of the fabric mat  36 . 
     The bearing sections  8 ,  9  of outer clamp  1  lie with their outward sides against the insertion opening  38  provided in carrier part  35 , and against a through-clearance  39  provided in the fabric mat  36 , whereas the inner sides of bearing sections  8 ,  9  butt against inner clamp  11  in response to even a relatively slight movement of the shank arms  3 ,  4  of outer clamp  1  toward each other, causing the outer clamp  1  to be anchored to the carrier part  35  with a high extraction force despite relatively flexible construction. 
       FIG. 4  shows the outer clamp  1  according to  FIG. 1  and the inner clamp  11  according to  FIG. 2  in a second longitudinal section, depicting the described exemplary embodiment of a device according to the invention in the arrangement of  FIG. 4 , the section plane of the second longitudinal section being roughly perpendicular to the section plane of the first longitudinal section, that of  FIG. 3 . It can be seen from  FIG. 4  that the on-lying tabs  23 ,  24  of inner clamp  11  are disposed in a receiving space  40  formed in the mounting housing  37 , and secure the mounting housing  37  to the carrier part  35  by the fact of the bearing sections  31 ,  32  of rear engagement tongues  27 ,  28  of inner clamp  11  bearing against the rim region of the insertion clearance  38 . Meanwhile, the hold-down tabs  9 ,  10  of outer clamp  1  are disposed in a chamber space  41  formed in the mounting housing  37 . 
       FIG. 5  is a side view of the outer clamp  1  according to  FIG. 1  and the inner clamp  11  according to  FIG. 2  as per the described exemplary embodiment of a device according to the invention, in an arrangement where the inner clamp  11  is pulled a displacement distance out of the outer clamp  1 , compared to the arrangement of  FIGS. 3 and 4 . The arrangement according to  FIG. 5  is realized, for example, when, after an airbag  42  of which the fabric mat  36  is a part has expanded, as illustrated schematically in  FIG. 5 , the depicted mounting housing  37  and any other mounting housings  37  (not shown) are lifted off the carrier part  35  as a result of the high forces in play after the deflection of the rear engagement tongues  27 ,  28  of inner clamp  11 . The ends of the stop dogs  25 ,  26  of the side legs  13 ,  14  of inner clamp  11  meanwhile butt against the rim region of the insertion clearance  38  of carrier part  35  and block any further withdrawal of inner clamp  11  from outer clamp  1 , short of excessive forces having a destructive effect. Since inner clamp  11  is still between the bearing sections  7 ,  8  of outer clamp  1 , even in this pulled-out arrangement, the solidity of the connection of the fabric mat  36  to the carrier part  35  is preserved, since the shank arms  3 ,  4  of the outer clamp  1  are still unable to move toward each other because of the locking action of the inner clamp  11 . 
     While this invention has been described as having a preferred design, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.