Abstract:
A w-based panel fastener for securing a molding to a panel includes a nose and a pair of offset wings extending from the nose. The nose has a longitudinal length, an outer surface, and an inner surface opposite the outer surface. The wings are spaced from each other along the longitudinal length of the nose, and each of the wings includes a guide portion extending from the outer surface of the nose and a retainer portion extending generally from the inner surface of the nose. The spaced apart guide portions of the wings form a surface for initial insertion into the opening in the panel. The retainer portion of the wings is adapted to interfit with the opening in the panel to secure the fastener to the panel.

Description:
FIELD OF THE INVENTION 
   The present invention relates generally to a retainer for fastening a molding to a panel, and more particularly to novel retainer design that provides superior installation, retention, removal and servicing capabilities. 
   BACKGROUND OF THE INVENTION 
   Automobile components, such as door trim panels, claddings, wheel lips and body side moldings are typically attached to vehicle panels comprised of plastic, sheet metal or another substrate material using various clips, such as conventional “w-based” clips. An exemplary conventional connection system installation using such w-based clips includes an exterior component affixed to a panel by means of the w-based clip. The installation process generally includes drilling or punching a slot or hole in the panel and subsequent insertion and snap-fitting of wings of the w-based clip, which is installed onto the exterior component, into the slot. 
   One common type of w-based clip, known as an “offset wing” clip, includes a solid, rounded nose that makes initial contact with the panel and is forced through the opening in the panel. A pair of wings extend from opposite sides of the nose for holding the retainer in the slot. The wings are commonly offset along the length of the bridge, and they each include a first portion that angles outwardly and a second portion that angles inwardly. In use, the offset wing clip is inserted by forcing the nose and the wings through the slot in the panel. The first portion of the wings flexes inwardly during insertion until it passes through the slot. The wings then expand outwardly to fill the hole, with the second portion of the wings engaging the hole to hold the retainer in place. 
   One drawback of the conventional offset wing retainer is the inability to effectively control the flexibility of the wings. As a result, it is difficult to control the forces that are required to insert the retainer into the sheet metal slot, to remove the retainer from the slot and to hold the retainer in the slot in the final assembly. This inability to control insertion and removal forces is especially problematic in situations where the retainer must perform to specified insertion and removal standards, and makes it difficult to adapt a particular retainer design to meet a variety of specifications. Accordingly, there remains a need for a panel retainer, and particularly an offset wing w-base retainer, that provides controllable insertion and removal forces without sacrificing retention values, manufacturing cost and efficiency. 
   SUMMARY OF THE INVENTION 
   The above-mentioned problems are overcome by the present invention, which provides an offset wing w-base retainer with a nose that is formed by a pair of interposing guide extensions. 
   In one embodiment, the retainer includes a collar, a pair of posts extending from the collar, and a bridge joining the distal ends of said posts. The bridge has a longitudinal length between the posts, an inner surface facing the collar, an outer surface opposite the inner surface, and first and second lateral sides. First and second wings extend from the bridge generally toward the collar with the first wing adjacent to the first lateral side and the second wing adjacent to the second lateral side. The wings are offset along the longitudinal length of the bridge. The guide extensions extend from the outer surface of said bridge and are separated by a gap. The first guide extension is positioned opposite the first wing and the second guide extension is positioned opposite the second wing. In one embodiment, a portion of material is removed from the inner surface of each guide extension. This removal of material may provide the inner surface of each guide extension with a concave shape. 
   In another embodiment, a fin extends from the outer surface of the bridge and is located in the gap between the guide extensions. The fin may extend above the outer edge of the guide extensions. 
   In another embodiment, the wings each include a first portion that extends from the bridge and angles generally away from the posts, a second portion that extends from the first portion and angles generally toward the posts, an outer surface and an inner surface. A support rib extends from the inner surface. At least a portion of the support ribs extends from the first portion of the wing, and at least a portion of the rib extends from the second portion of the wing. 
   The present invention provides an offset wing, w-base retainer that enables control of the insertion and removal forces of the retainer, while providing for the proper hold force in the assembled position. The guide extensions function similar to the solid, rounded nose of a conventional offset wing retainer, but provide greater flexibility, and increased control of the flexibility, of the wings of the present invention. The separation of the guide extensions opposite each of the wings provides an adequate guide for inserting the retainer into the panel while allowing each wing to flex essentially independently from the other. The size of the gap between the guide extensions can be varied depending on the desired flexibility of the wings, and the size, shape and removal of material from the guide extensions enables additional control of the flexibility of the wings. The fin acts as an additional guide for insertion of the retainer and also protects the guide extensions, and the support rib on the back side of the wing increases the strength of the wings without sacrificing the ability of the wings to flex with respect to the bridge. 
   Other features and advantages of the invention will become apparent to those skilled in the art upon review of the following detailed description, claims and drawings in which like numerals are used to designate like features. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a bottom perspective view of a panel fastener according to one embodiment of the present invention. 
       FIG. 2  is a top perspective view of the panel fastener thereof. 
       FIG. 3  is a bottom view of the panel fastener thereof. 
       FIG. 4  is a front view of the panel fastener thereof. 
       FIG. 5  is a top view of the panel fastener thereof. 
       FIG. 6  is a side view of the panel fastener thereof. 
       FIG. 7  is a perspective view of the panel fastener assembled with a molding and a panel. 
       FIG. 8  is an exploded view of the panel fastener, molding and panel. 
       FIG. 9  is a cross sectional view of the panel fastener, molding and panel taken along line  9 - 9  in  FIG. 7 . 
       FIG. 10  is a cross sectional view of a panel fastener, molding and panel taken along line  10 - 10  in  FIG. 7 . 
   

   Before the embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein are for the purpose of description and should not be regarded as limiting. The use of “including” and “comprising” and variations thereof is meant to encompass the items listed thereafter and equivalents thereof as well as additional items and equivalents thereof. 
   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   A panel fastener according to one embodiment of the present invention is shown in  FIG. 1  and generally designated  10 . As shown in  FIG. 7 , the fastener  10  is designed to secure a molding  100  to a panel  102 . For purposes of illustration, an exemplary molding  100  and panel  102  are shown in  FIGS. 7-10 . The molding  100  is typically a plastic, injection molded part, that may form, for instance, a portion of an automobile door trim panel. In the illustrated exemplary embodiment, the molding  100  is a flange with a keyhole shaped opening  103  to receive a portion of the retainer  10 . The molding  100  may also include a pair of windows  105 ,  107  on opposite sides of the opening  103 . The panel  102  is typically a sheet metal piece, plastic piece, or another substrate material, that may form, for instance, an automobile door. The exemplary panel  102  includes a slot  109  into which the retainer  10  may be inserted. 
   The fastener  10  is typically made of injection molded plastic, but may be comprised of a variety of materials. In one embodiment, the fastener includes a head plate  20 , a collar  22 , and a neck  21  joined between the head plate  20  and the collar  22  and forming a gap between the head plate  20  and the collar  22 . In the illustrated embodiment, the head plate  20  is a generally flat, rectangular plate having a lower surface  24 , an upper surface  26 , and first and second longitudinal ends  28  and  30 . The lower surface  24  includes two notches  32  and  34  that provide portions of reduced thickness in the head plate  20 . These reduced thickness portions increase the flexibility of the head plate  20 . Additional notches may be included in a variety of shapes, sizes and locations depending on the desired flexibility of the head plate  20 . In one embodiment, a pair of locking tabs  36  and  38  extend from the upper surface  26  of the head plate  20  adjacent to the longitudinal ends  28  and  30 . The locking tabs  36  and  38  interfit with windows  105 ,  107  in the molding  100  (described in more detail below) to provide a secure attachment of the fastener to the panel, while also preventing rotation of the panel fastener  10  with respect to the molding  100 . As shown in  FIGS. 4 and 6 , the neck  21  is generally cylindrical and includes a first end  40  attached to the head flange  20  and a second end  42  attached to the collar  22 . In one embodiment, the collar  22  is also a generally flat plate that includes a lower surface  44  attached to the neck  21  and an upper surface  46  opposite the lower surface  44 . 
   Referring to  FIGS. 2 and 4 , a pair of posts  50 ,  52  extend from the upper surface  46  of the collar  22 . In one embodiment, the posts  50 ,  52  each include a base  54  adjacent to the collar  22  and a distal end  56  defining a height  58  between the base  54  and the distal end  56 . The posts  50 ,  52  also each include a thickness  60  generally perpendicular to the height  58  and a width  62  generally perpendicular to the thickness  60 . In the illustrated embodiment, the width  62  tapers from the base  54  to the distal end  56 . As described in more detail below, the tapered shape of the posts  50 ,  52  allows the posts to tightly engage slot  109  in the panel  102  even in cases where the size of the slot  109  varies slightly from panel to panel. The distal ends  56  of the posts  50 ,  52  are joined by a bridge  70 . The bridge  70  is generally flat, and defines a longitudinal length extending between the posts  50 ,  52 . The bridge additionally includes an upper surface  72 , a lower surface  74 , and first and second lateral sides  76 ,  78 . 
   A pair of wings  80 ,  82  extend from the bridge  70  generally toward the collar  22 . In one embodiment, a first wing  80  extends from the bridge adjacent the first lateral side  76  proximate to the first post  50  and a second wing  82  extends from the bridge adjacent the second lateral side  78  proximate to the second post  52 , such that the wings are offset along the length of the bridge  70 . In one embodiment, the wings  80 ,  82  are offset along the length of the bridge  70  such that they define a gap  84  between the wings  80 ,  82 . The gap  84  is controlled to provide clearance between the wings  80 ,  82  when they are flexed inwardly. It also is designed so that the wings will interact to support each other if a cross load is applied. Each wing  80 ,  82  includes a first portion  86  extending from the bridge  70  and a second portion  88  extending from the first portion  86 . The first portion  86  angles outwardly from the posts  50 ,  52  and the second portion angles generally toward the posts  50 ,  52 . Each wing additionally includes an outer surface  90 , an inner surface  91 , and a ledge  92  extending from the outer surface  90 . As illustrated, the ledge  92  is positioned at the junction between the first  86  and second  88  portions of the wings  80 ,  82 . The ledge  92  includes a lower surface  94  that forms an angle with the second portion  88  of the wings  80 ,  82 . As described in more detail below, in use, the lower surface  94  of the ledge  92  impedes removal of the retainer  10  from the panel  102 . The angle between the lower surface  94  and the second portion  88  can be varied depending on the desired removal force. In embodiment, each wing  80 ,  82  also includes a support rib  93  extending from the inner surface  91  to provide the wing  80 ,  82  with additional strength. In the illustrated embodiment, the support rib  93  extends from the inner surface  91  with a first portion  95  of the support rib  93  extending from the first portion  86  of the wing  80  and a second portion  97  of the support rib  93  extending from the second portion  88  of the wing  80 . The support rib  93  strengthens the wings  80 ,  82  in the area of the junction between the first  86  and second  88  portions of the wings  80 ,  82  without substantially altering the flexibility of the wings  80 ,  82  with respect to the bridge  70 . 
   A pair of interposing guide extensions  96 ,  98  extend from the upper surface  72  of the bridge  70 . In one embodiment, the guide extensions  96 ,  98  act as a nose for guiding the retainer into the slot or hole  109  in the panel. In the illustrated embodiment, the first guide extension  96  extends from the bridge  70  opposite the first wing  80 , and the second guide extension  98  extends from the bridge  70  opposite the second wing  82 . In one embodiment, the guide extensions  96 ,  98  each include an outer surface  110  that angles inwardly generally in line with the first portion  86  of the wings  80 ,  82 . The guide extensions  96 ,  98  additionally include an inner surface  112 . In one embodiment, material is removed from the inner surface  112  to increase the flexibility of the wings. As shown, the inner surface  112  of each guide extension  96 ,  98  is cut so that it is concave. The guide extensions  96 ,  98  may each also include a longitudinal edge  115  that angles inwardly along the longitudinal length of the bridge  70 . The angle of the longitudinal edges  115  can be varied to provide a lead-in for the retainer  10  as it is inserted into the slot  109  in the panel  102 . The guide extensions may be separated by a gap  114  that allows each guide extension  96 ,  98  and its corresponding wing  80 ,  82  to flex independently from the other guide extension  96 ,  98  and wing  80 ,  82 . The width of the gap  114  may be varied as desired to control the flexibility of the wings  80 ,  82 . An increase in the size of the gap  114  also increases the flexibility of the wings  80 ,  82 . In one embodiment, a fin  116  is disposed on the bridge within the gap  114 . In one embodiment, the fin  116  extends from the upper surface  72  of the bridge  70  and includes a fin base  118  that spans the width of the bridge  70  from the first lateral side  76  to the second lateral side  78 . The fin  118  may have a rounded outer edge  120  that provides a nose to enable easier insertion of the retainer  10  into the panel  102 . In the illustrated embodiment, the outer edge  120  of the fin  118  extends above the guide extensions  96 ,  98  to protect the guide extensions  96 ,  98  during insertion. 
   In operation, the retainer  10  is attached to the molding  100  by inserting the neck  21  into the keyhole shaped opening  103  in the molding, with the molding fitting between the head plate  20  and the collar  22 . The notches  32  and  34  allow the head plate  20  to flex as the neck  21  is inserted into the opening  103 . In one embodiment, the neck  21  snap-fits into the opening  103 . The locking tabs  36  and  38  may fit into the windows  105  and  107  to provide a secure attachment and prevent rotation of the retainer  10  relative to the molding  100 . 
   The retainer  10  is attached to the panel  102  by inserting the retainer through the slot  109  in the panel  102 . As shown in  FIG. 8 , the retainer is aligned with the slot  109  and positioned such that that fin  116  and guide extensions  96 ,  98  (shown in  FIG. 2 ) are adjacent to the slot  109 . The retainer  10  is then inserted through the slot  109 . As the retainer is inserted, the first portion  86  of the wings  80 ,  82  contacts the panel  102  and the wings  80 ,  82  flex inwardly until the retainer  10  is inserted past the first portion of the wings  80 ,  82 . The angle of the second portion  88  of the wings  80 ,  82  then acts to hold the retainer in the slot  109 , with the second portion  88  engaging the slot  109 . The base  54  of the tapered posts  50 ,  52  (at width  62 ) substantially fills the slot  109  to prevent damage to the wings  80 ,  82 , for instance, when a rotational force is placed on the retainer  10 . The ledge  92  prevents the retainer  10  from being removed from the slot  109 . 
   Variations and modifications of the foregoing are within the scope of the present invention. It is understood that the invention disclosed and defined herein extends to all alternative combinations of two or more of the individual features mentioned or evident from the text and/or drawings. All of these different combinations constitute various alternative aspects of the present invention. The embodiments described herein explain the best modes known for practicing the invention and will enable others skilled in the art to utilize the invention. The claims are to be construed to include alternative embodiments to the extent permitted by the prior art. 
   Various features of the invention are set forth in the following claims.