Abstract:
A fastener for fixing a panel to a support is provided with a snapping-in foot adapted to contract elastically to enter a fixing orifice of the support. The fastener is further provided with a head having a plate, a hub, a shank and a deformable member, the plate and the hub being connected by the shank adapted to be received in a keyhole-shaped groove of the panel formed within the thickness of the panel in which the member and the hub are adapted to be received. The fastener also has a deformable rim including a plurality of arcs and deformable arms, each disposed between one of the arcs and the hub.

Description:
RELATED APPLICATIONS 
     The present application is based on, and claims priority from, French Application Number 04 07378, filed Jul. 2, 2004, the disclosure of which is hereby incorporated by reference herein in its entirety. 
     FIELD OF THE INVENTION 
     The invention relates generally to fasteners for fixing a panel to a support such as a car body panel. 
     BACKGROUND OF THE INVENTION 
     There is known in the art a fastener provided with a snapping-in foot adapted to contract elastically to enter a fixing orifice of predetermined diameter of the support. This fastener is further provided with a head comprising a rigid plate, a rigid counter-plate, and a deformable flange. The plate and the counter-plate are offset axially and connected by a shank. The plate and the flange are also offset axially and connected by a shank. 
     The panel has a keyhole-shaped groove opening into a larger void and in which the flange and the counter-plate are placed, while the plate and the foot of the fastener remain outside the panel, the foot being adapted to be inserted into the orifice of the support. 
     The flange takes the form of a rigid rim attached to the center of the flange by curved arms. The arms have some flexibility, enabling the flange to deform when moving in the void. 
     To position the fastener in the panel, the head is pushed into the circular part of the groove until the flange is at the height of the void under the elongate part of the groove. The flange and the plate are then caused to slide in the void. 
     If the axis of the fastener is not perfectly transverse to the sliding motion, certain parts of the flange abut against surfaces of the void. The deformation of the flange means that it does not block the sliding movement. 
     Once the fastener is in position in the void, the flange relaxes and the fastener is recentered. 
     When fastening a panel to a support, the deformable flange allows the foot of the fastener to be inserted into an orifice in the support even if the latter is slightly offset relative to the geometry of the groove. 
     The smaller counter-plate is situated against one of the surfaces of the void and prevents the fastener being pulled out. 
     SUMMARY OF THE INVENTION 
     The invention aims to provide a fastener of the above type offering the possibility of cooperating with thin panels whilst at the same time being particularly simple and convenient to manufacture and use. 
     To this end, the invention proposes a fastener for fixing a panel to a support and provided with a snapping-in foot adapted to contract elastically to enter a fixing orifice of said support, said fastener being further provided with a head comprising a rigid plate, a rigid counter-plate, and a deformable member, said plate and said counter-plate being connected by a shank adapted to be received in a keyhole-shaped groove of said panel opening into a void formed within the thickness of said panel in which said member and said counter-plate are adapted to be received, which fastener is characterized in that it comprises a generally round chock having a hub, a deformable rim comprising a plurality of arcs and deformable arms each disposed between one of said arcs and said hub with said hub that forms said counter-plate whereas said arcs and said arms form said deformable member. 
     Thus the fastener includes a chock that both prevents pulling out and deforms to allow easy positioning. 
     According to features of the invention that are particularly simple and convenient both to manufacture and to use:
         said hub is generally square and comprises four corners projecting with respect to said shank; and optionally   said hub has an edge surface on which four of said arms are rooted, each in the vicinity of one of said corners of said hub; and optionally   a first end of each of said arms is connected to one side of said edge surface and a second end of each of said arms is connected to a respective one of said arcs which extends generally facing said side whereas said arm is obliquely disposed between said side and said arc; and optionally   each of said sides comprises a toe extending in the direction of said rim, said toe being situated between said first end of said arm and said corner in the vicinity of said first end; and/or   said rim comprises, for each pair comprising two of said arcs having facing adjacent ends, a bridge extending between said adjacent ends; and/or   said fastener comprises a frustoconical skirt connected to said plate and flared in the direction therefrom toward said snapping-in foot; and/or   said head is formed in one piece with said body; or   said plate is extended by a peripheral ring from which extends a frustoconical skirt flaring therefrom toward said snapping-in foot, said ring and said skirt being molded onto said plate; and/or   said fastener is molded from a plastics material.       

     The invention also proposes an assembly intended to be fixed to a support, comprising a panel having at least one keyhole-shape groove opening into a void formed within the thickness of said panel and at least one fastener for fixing said panel to said support comprising a snapping-in foot adapted to contract elastically to enter a fixing orifice of said support, said fastener further comprising a head comprising a rigid plate, a rigid counter-plate and a deformable member, said counter-plate and said member being received in said void, said plate and said counter-plate being connected by a shank adapted to be received in said keyhole-shaped groove of said panel, and said plate being situated on an exterior surface of said panel comprising said groove, which assembly is characterized in that said fastener comprises a generally round chock having a hub and a deformable rim comprising a plurality of arcs and deformable arms each disposed between one of said arcs and said hub with said hub that forms said counter-plate whereas said arcs and said arms form said deformable member. 
     According to features of the invention that are particularly simple and convenient both to manufacture and to use:
         the depth of said void substantially corresponds to the thickness of said chock; and/or   the depth of said groove substantially corresponds to the height of said shank; and/or   the keyhole-shaped groove has a circular portion and an elongate portion and said elongate portion of said groove has a width slightly less than the diameter of said shank at the junction with said circular portion and a width substantially equal to said diameter over the remainder of said elongate portion.       

    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
       The features and advantages of the invention will emerge from the following description, which is given by way of preferred but non-limiting example, and with reference to the appended drawings, in which: 
         FIG. 1  is a perspective view of a fastener of the invention; 
         FIG. 2  is another perspective view of the fastener; 
         FIG. 3  is a view of the hub, the arms and the rim of the fastener; 
         FIG. 4  is a profile view of the fastener in which the panel and the support with which the fastener cooperates are seen in section; 
         FIG. 5  is a view in section taken along the line V-V in  FIG. 3 ; 
         FIGS. 6 to 9  are similar to  FIGS. 1 ,  2 ,  4  and  5 , respectively, for a different embodiment of fastener,  FIG. 9  being a view in section taken along the line IX-IX in  FIG. 6 ; and 
         FIG. 10  is a diagrammatic view of an assembly of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The fastener  1  shown in  FIGS. 1 to 5  is molded in one piece from a plastics material. It comprises a head  2  and a snapping-in foot  3 . 
     The head  2  includes, starting from its end opposite the foot  3 , a chock  4 , a shank  5 , a plate  6  and a sealing skirt  7 , these various components being coaxial with each other and each having a generally circular shape. 
     The chock  4  includes a generally square hub  8 . It extends around a central circular orifice  9 . This orifice  9  is an extension of the hollow interior portion of the shank  5 . The base  8  has four rounded corners  10 . The chock  4  further includes four arms  11  each extending from one of the four sides  12  of the hub  8 . 
     The arms  11  extend from the edge surface of the chock  4 . The hub  8  and the arms  11  all have the same, generally constant thickness. 
     The chock  4  has quarter-turn symmetry of rotation, and there will be described in detail only one pair comprising a side  12  of the hub  8  and the corresponding arm  11 . 
     In the vicinity of a rounded corner  10 , the side  12  features a recess in the shape of a circular arc extended at the end opposite the corner  10  by the root  13  of the arm  11 . 
     The arm  11  extends from the root  13  to an elbow  16  formed at the junction with an arc  14  that is part of a rim  15 . Each arm  11  is extended by an arc  14 . All the arcs  14  are identical and have a generally constant thickness equal to that of the arms  11 . 
     In the direction away from the root  13 , the arm  11  extends in rectilinear fashion as far as the elbow  16  and the angle between the arm  11  and the side  12  is a small acute angle. 
     The arc  14  is slightly rounded. The angle at the bend  16  between the arm  11  and the arc  14  is also an acute angle and of the same order of magnitude as the above angle. The end  17  of the arc  14  opposite the elbow  16  faces the corner  10 . The arc  14  features two semicylindrical beads  18  forming ejection bosses. They are situated on the face of the arc  14  facing the side  12 , one in the vicinity of the elbow  16  and the other at the end  17 . 
     The thickness of the arm  11  and of the arc  14  is such that they have an overall stiffness. However, the arm  11  is flexible relative to the side  12  and the arm  11  and the arc  14  are flexible relative to each other. 
     The rim  15  is circular and is generally formed by the four arcs  14 . 
     The arcs  14  are separated from each other but connected two by two by a bridge  20 . Each bridge  20  extends from one end  17  of an arc  14  and the elbow  16  to the other end of an adjacent arc  14 . The four bridges  20  are also in the shape of circular arcs so that they close the periphery of the chock  4 . Each bridge  20  is half the thickness of the chock  4  and in the direction of this thickness each bridge extends from the face of the chock  4  adjacent the shank  5 . 
     The thickness of the plate  6  is much less than the height of the shank  5  or that of the chock  4 , which are substantially equivalent. On the other hand, the plate  6  and the chock  4  have substantially the same diameter. 
     The sealing skirt  7  extends from the face of the plate  6  opposite the shank  5 . The skirt  7  is frustoconical, its height is comparable to that of the chock  4 , and it is particularly thin. 
     The radius of the free edge of the skirt  7  is substantially the same as that of the plate  6 , whereas the radius of the junction with the plate  6  is very much less. 
     The snapping-in foot  3  includes a flat core  30  and two curved wings  31  each extending from the flat core  30 . 
     The core  30  is oriented in an axial plane and converges toward the free end  21  of the foot  3 , which is pointed. The other end of the core  30  is connected to the head  2 , to be more precise to the plate  6 , on the side opposite the shank  5 . 
     The wing  31  ( FIGS. 4 ,  5 ) is connected to the core  30  along an edge surface  32  of the core  30  and has, facing the plane face  33  of the core  30 , an internal surface  34  flanked by the face  33 , a longitudinal edge surface  35  and a transverse edge surface  36  facing the face  6 . 
     The internal surface  34  of the wing  31  is concave and in the present example has a profile that generally follows that of the external surface of the foot  3 . 
     The foregoing description is equally valid for the second wing  31 . 
     On respective opposite sides of a plane  40  of inflexion ( FIG. 5 ) oriented transversely to the axial direction of the foot  3 , the external surface of the latter tapers respectively toward the pointed end  21  of the foot  3  and toward the transverse edge surfaces  36  of the wings  31 . 
     The external surface of the foot  3  has an edge (not visible) at the level of the plane  40  and having a generally oval shape. 
     Each wing  31  has a generally constant thickness, but with a slightly reduced thickness toward the longitudinal edge surface  35 . 
     The annular space situated around the shank  5  and between the chock  4  and the plate  6  is adapted to be received in a groove of a facing panel  41  such as an automobile body lateral embellisher ( FIGS. 4 ,  10 ). In the present example the panel  41  includes a keyhole-shaped groove  42  whose circular portion has a diameter corresponding to that of the chock  4  and whose elongate portion has a width corresponding to that of the shank  5 . The thickness of the wall of the panel  41  in which the elongate portion is formed corresponds to the height of the shank  5 . The elongate portion opens into an void whose width substantially corresponds to the diameter of the rim  15  and whose thickness substantially corresponds to that of the chock  4 . Thus the void opens at one end into the circular portion, the depth of the circular portion corresponding to the combined thickness of the elongate portion of the groove  42  and that of the void. 
     The elongate portion has a width slightly less than the diameter of the shank  5  at the junction with the circular portion and a width substantially equal to the diameter over the remainder of the elongate portion. 
     The chock  4  is fitted to the panel  41  by pressing the chock  4  into the circular portion until it is pushed far enough in to move in translation into the void under the elongate portion. Because of the reduction in the width of the groove  42  at the junction between the circular and elongate portions, the shank  5  has to be forced into the elongate portion of the groove  42 . The fastener  1  is then slid toward the back of the elongate portion. 
     Ideally, the fastener  1  is offered up to the circular portion on the axis of the circular portion and slid parallel to the orientation of the elongate portion and transversely to the axis of the fastener  1 . However, these operations are generally carried out in such a way that the axis of the fastener is rarely transverse to the sliding movement. 
     With the axis of the fastener  1  inclined to a transverse direction on sliding, the center of the chock  4  is offset from the middle of the void and the chock  4  is not flat in the void. In this position, the rim  15  is deformed, to a degree that depends on the inclination. 
     If the rim  15  necessitates a small deformation, only one arc  14  flexes, independently of the others. If the deformation is greater, the arm  11  flexes as well as the arc  14 . In an extreme situation, the load is transmitted to an adjacent arm via a bridge  20 . 
     Once positioned in the elongate portion, the fastener can be recentered since the arms  11  and the arcs  14  resume a relaxed position in which the axis of the fastener is transverse to the panel  41 . 
     The fastener  1  is retained in the void by the ring  15 , whose dimensions are adapted to immobilize the fastener  1 . 
     The dimensions of the chock  4  are matched to those of the void, which avoids vibrations causing noise and the risk of the panel separating from the support. Despite the fabrication tolerances of the panel  41  and the fastener  1  and the geometry of the void, this matching is possible thanks to the presence of the deformable rim  15  and the deformable arms  11  on the chock  4 . 
     The fastener  1  and the panel  41  thus form an assembly ready to be fixed to a support  50 . 
     The support  50  ( FIG. 4 ) to which the fastener  1  is to be fixed has a circular contour orifice  22  having a diameter less than the maximum radial dimension of the foot  3  (that maximum radial dimension is in the plane  40 ). 
     With the head  2  positioned in the panel, the foot  3  is forced into the orifice  22 , with the tip  21  of the foot  3  first, cooperation between the perimeter of the hole and the portion of the wings  31  situated between the end  21  and the plane  40  having the effect of causing the wings  31  to flex progressively until this portion of the foot has passed through the orifice  22 . The wings  31  relax, the effect of which is to entrain the foot  3  in the pressing-in direction until this results in abutment against the face of the support  50  situated on the side from which the foot  3  has been pressed in. The sealing skirt  7  is then pressed against the panel  50 . 
     If the orifice  22  in the support  50  is not perfectly aligned with the groove  42 , the latter must be inclined to insert it into the orifice  22 . The chock  4  is then no longer flat in the void, and an arc  14  (and where applicable an arm  11 ) is (are) flexed to allow positioning of the fastener  1  in the panel and the support. This situation may arise in particular when using a panel and a support that must be fixed by means of more than one fastener  1 . 
     Because the sealing skirt  7  is thin, the abutting engagement at the end of pressing in the foot  3  is obtained on the panel  41  rather than on the fastener  1 . 
     The four corners  12  of the hub  8  provide resistance to pulling the panel  41  off the support  50  at four points. If traction is applied in the pulling off direction, the four corners  12  bear against an internal surface  51  of the panel  41  in the void with the result that the chock  4  cannot deform at the level of the hub  8  in this direction parallel to the axis of the fastener  1 . Thus it cannot be pulled through the elongate portion of the groove  42  if excessive traction is exerted on the fastener  1 . This resistance to pulling off is accentuated by the arms  11  and the rim  15 . Those components are deformable, but each arm  11  and the associated arc  14  are relatively substantial around the hub  8 , which limits their deformation in a direction parallel to the axis of the fastener  1 . The chock  4  combines the function of preventing pulling out and the function of beneficial deformation, in particular when fitting the fastener into the panel and into the support. 
     To disengage the panel  41  from the support  50 , a traction force is applied to the panel. The fastener  1  is not pulled out, thanks to the projecting corners  12 . During this movement, the fastener  1  may be subjected to a force in the direction parallel to the axis of the fastener  1 . It is generally subjected to successive forces in different directions so that the chock  4  is deformed, without breaking, as a function of these forces, in the same manner as described above. The foot  3  is then less able to resist pulling out and leaves the orifice  22  in the support  50  with a movement that is the reverse of that described above. 
     Then, if necessary, the fastener  1  is removed from the panel  41  by sliding the fastener  1  along the elongate portion of the keyhole-shaped groove  42 . 
     Referring to  FIGS. 5 to 9 , in another embodiment, the fastener  1  has a hub  8 , a plate  6  and a sealing skirt  7  each having a form different from that of the corresponding component in the embodiment described above. These differences do not modify the various properties and behaviors of the fastener as described above. 
     The hub  8  has four triangular orifices  60  regularly distributed around the central circular orifice  9 . Instead of recesses in the shape of circular arcs, the hub  8  has four toes  61  projecting toward the facing arc  14 . These toes project further relative to the shank  5  than the corners  12  and provide good resistance to pulling out. 
     The plate  6  is radially smaller than in the previous embodiment, and also thicker. The perimeter of the plate  6  bears on a peripheral ring  62  that is extended toward the foot by a sealing skirt  7  that is flared toward the foot  3 . The skirt  7  is less flattened. The slope of the lateral surface of the skirt  7  is much more pronounced. 
     The ring  62  and the skirt  7  are molded onto the plate  6  in one piece from a plastics material. Thus a plastics material may be selected that is different from that forming the rest of the fastener  1 . Particularly good sealing properties can be obtained in this way, if necessary. 
     In one variant of the system, the panel includes keyhole-shaped grooves including a notch transverse to the elongate portion, into which notch the fastener is wedged. 
     In another variant, the system includes a panel having a plastics material block fixed into an void of corresponding dimensions. The block features a keyhole-shaped groove adapted to receive the fastener. 
     Alternatively, the foot of the fastener has different wings. 
     More generally, other foot shapes for the fastener with a deformable chock as described are feasible. 
     The present invention is not limited to the embodiment described and shown and encompasses any variant execution thereof.