Patent Abstract:
A w-base fastener that may be used in many applications, including numerous applications throughout the automotive industry, combines the functionality of a w-base fastener with the serviceability of other fasteners. The w-base fastener of the invention provides the ability to service the w-base fastener without damaging the panel or hole in which the fastener is inserted. This is accomplished by incorporating a break joint configured to break at a predetermined load. This break joint permits the fastener to be easily extracted when it breaks under the predetermined load. As the two sections of the fastener are separated, hooks on the fastener body engage tabs on the legs and pull the legs of the w-base fastener inward to prevent interference between the legs and the panel as the fastener is extracted from the hole.

Full Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This Non-Provisional Application claims benefit to U.S. Provisional Application Ser. No. 60/878,825 filed on Jan. 5, 2007. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates generally to fasteners, and more particularly, to w-base fasteners. 
     BACKGROUND OF THE INVENTION 
     It is known that fasteners are used in various applications to perform various functions. It is further known that numerous types of fasteners are used in various automotive applications. A common fastener that is widely used throughout a vehicle is known as a w-base clip or w-prong fastener (hereinafter “w-base fastener”). The w-base fastener and its fastening scheme provide a simple yet effective solution to many fastening needs. As a result, this fastener is economical, functional, and widely accepted among the automotive industry. Exemplary w-base fasteners are disclosed in U.S. Pat. Nos. 5,851,097 and 5,797,714, both assigned to Illinois Tool Works, Inc. 
     Regardless of size or complexity, the w-base fastener utilizes some basic principles in fastening. These principles include multiple legs that compress towards a common member, of which the legs are attached, during the installation in a hole. These legs then expand to engage the backside of the hole to which the fastener is mounted to hold the fastener in a mounted position within the hole. The fastener also includes a head or similar structure that permits items to be mounted to the fastener. The w-base fastener provides an excellent method of retention with an outstanding insertion to extraction force ratio. 
     A known drawback exists, however, when servicing or replacing the known w-base fastener. This problem occurs when the backside of the hole in which the fastener is inserted is not accessible for disengagement of the legs. In this situation, which is a common occurrence in a vehicle, the hole may be damaged upon extraction of the w-base fastener, rendering the hole useless. In other situations, the legs of the fastener may break at a certain load, with the resulting broken w-base pieces remaining in the hole. The invention overcomes these and other known problems by providing a means of securing the w-base fastener to the hole with the option of servicing or replacing the fastener should the need arise without damaging the hole when the fastener is extracted and without leaving any portion of the fastener in or behind the hole. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to a w-base fastener that may be used in many applications, including numerous applications throughout the automotive industry. The invention provides a fastener that combines the functionality of a w-base fastener with the serviceability of other fasteners. Indeed, the invention provides the ability to service the w-base fastener without damaging the panels or hole in which the fastener is inserted. 
     The invention achieves this desired serviceability by providing a w-base fastener that incorporates a breakaway or extension element. This element can be one of multiple embodiments that achieve this serviceability objective. Upon insertion, the w-base fastener of the invention functions in a manner similar to known w-base fastener designs. That is, the legs flex inward toward a common member by pressure exerted on the legs by the edge of the hole. After completely passing through the hole, the legs flex outward creating an interference fit between the backside of the hole and the legs, thereby securing the fastener to the hole. A break point or extension joint is provided in the base of the fastener to either detach or extend under a predetermined load, such as during separation of a secondary panel from a primary panel. The fastener is configured to include hooks disposed on the body to grab the w-base legs during removal and force the legs to collapse during extraction of the fastener from the hole so that the entire fastener can pass freely through the hole without causing damage to the hole. 
     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 an isometric view of an exemplary embodiment of a w-base fastener of the present invention. 
         FIG. 2  is a side view of the embodiment of  FIG. 1 . 
         FIG. 3  is a close-up isometric view of a hook element and a leg element of the embodiment of  FIG. 1 . 
         FIG. 4  is a close-up isometric view of a hook element and a leg element of an additional embodiment of a w-base fastener of the present invention. 
         FIG. 5  is an isometric partial view of an exemplary embodiment of an installed w-base fastener of the present invention, illustrating the positions of the hook and leg after the fastener has been subjected to a load sufficient to separate the fastener at the break joint. 
         FIG. 6  is an isometric partial view of the w-base fastener of  FIG. 5 , illustrating the positions of the hook and leg as the fastener is being uninstalled, after the upper portion of the fastener has been pulled away from the lower portion of the fastener. 
         FIG. 7  is an isometric partial view of an exemplary embodiment of a w-base fastener of the present invention, during installation into a panel. 
         FIG. 8  is a close-up isometric view of the hook and leg element of  FIG. 3  shown in another position. 
         FIG. 9  is a side view of the embodiment partially illustrated 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 EMBODIMENTS 
     The present invention may be embodied in many forms. In one exemplary embodiment depicted in  FIG. 1 , the present invention is directed to a w-base fastener or clip  10  that, as discussed below, provides the ability to service the w-base fastener without damaging the panel and/or hole in which the fastener is inserted, and without leaving any portion of the fastener in the hole. Additionally, the invention provides the functionality of traditional w-base fasteners with the serviceability of other fasteners. 
     Referring to  FIGS. 1 and 2 , the w-base fastener  10 , which may be made of plastic or any other suitable material, includes a head  20 , a body  22 , and a plurality of legs  24  that are joined to the body  22  below a break point or extension joint  28 . The head  20  is used to prevent the fastener  10  from completely passing through the panel or hole in which the fastener is mounted. The head  20  may define numerous shapes and configurations, including the depicted multi-disk-shaped configuration. The head  20  may define a first, second and third disc-shaped head portion  20   a ,  20   b  and  20   c , respectively. As further illustrated in  FIG. 1 , the first head portion  20   a  may define a disc-shape angularly extending contact surface  23  that, in use, serves to prevent the fastener  10  from completely passing through the panel or hole in which the fastener  10  is mounted. This is accomplished by the configuration of the head portion  20   a , which defines a diameter that is greater than the diameter of the hole in which the fastener is mounted. As mounted to a panel, the angular configuration of the head portion  20   a  may provide a resiliency, similar to a spring washer, to further secure the fastener  10  to the panel. 
     The second head portion  20   b  and third head portion  20   c  may serve as mounting members to permit other structures or items to be mounted to the fastener  10  vis-à-vis the second and third head portions. The second head portion  20   b  and third head portion  20   c  may be disc-shaped or define other shapes and may be joined together by, and spaced apart from each other by an intermediate portion  21 . The intermediate portion  21  defines a diameter that is less than the diameters of the second head portion  20   b  and third head portion  20   c  and a height that permits adequate spacing between the second head portion  20   b  and third head portion  20   c . As can be appreciated, with the depicted configuration, items or other structures may be mounted to the intermediate portion  21  between the second and third head portions. One of skill in the art will appreciate that the head  20  may define numerous other known head configurations that permit the mounting of other structures to the fastener  10  and that prevent the fastener from being pulled through the hole or panel to which it is mounted. Consequently, the illustrated head  20  is merely an example of one of the many possible configurations. 
     Continuing to refer to  FIGS. 1 and 2 , connected to or formed integral with the head  20  is the body  22  or common member. The body  22  may extend outwardly from the head portion  20   a  and define an elongated member that provides the structure on which a plurality of legs  24  may be attached. The body  22  may define a cylindrical or rectangular configuration or any other possible configuration. In the exemplary embodiment, a plurality of hooks  26  may be attached to the body  22  between the break joint  28  and the head  20   a . The hooks  26  extend outwardly, such as perpendicularly, from the body  22  to engage the legs  24  during extraction and force the legs  24  to bend inward towards body  22 . As depicted, one hook  26  extends between the body  22  toward each leg  24 . The hooks  26  are joined to the body  22  below tab  30  of each leg  24 . 
     In use during removal of the fastener  10 , once the head  20  is pulled and the break joint  28  has been broken, the portion of the fastener  10  above the break joint may be moved upward to cause the hook  26  to engage the tab  30  on the leg  24 . This engagement causes the legs  24  to move inward toward the body  22 . Drawing each leg  24  toward the body  22  allows the entire fastener  10  to be removed without interference with the edge of the hole. In the embodiment shown, the tab  30  may be angled to correspond to the angle of the hook  26 . The hook  26  may define numerous configurations that serve to connect the body  22  to each leg  24  during extraction and provide a technique for pulling or drawing each leg  24  toward the body  22 . 
       FIG. 3  provides a close-up isometric view of  FIG. 1  and includes the hook  26  and tab  30  areas of fastener  10 . In one embodiment, as the legs  24  are drawn toward the body  22 , the tab  30  moves in a downward direction. In this embodiment, with additional reference to  FIG. 8 , a leg tab notch  32  disposed on an upper end of the tab  30 , engages with a hook tab  27  to lock the legs  24  with the hook tab  27  on hook  26  to stop the downward direction of the tab  30  and keep the tab  30  secured during extraction. The hook tab  27  may be configured to generally correspond in shape to the leg tab notch  32  to provide secure engagement of the hook tab  27  and leg tab notch  32 . 
     As shown in the embodiment illustrated in  FIG. 4  and  FIG. 8 , hook  26  may further comprise a lead-in element  34  to assist in the initial engagement of tab  30  to hook  26 . The embodiment may also include a ledge  31  disposed on body  22 , the ledge  31  configured to provide a positive stop for the downward movement of leg  24  once it is engaged by hook  26  and drawn in towards the body. The ledge  31  may thus prevent the leg  24  from being capable of sliding below the hook  26 . 
     Referring back to  FIG. 2 , the legs  24  are joined at the common end  38  which may form or define a point or tip that is configured to facilitate the insertion of the fastener  10  into the panel or other surface to which the fastener is mounted. In an embodiment, the body  22  defines opposing tapered portions  36  that enhance the insertion of the fastener  10  into the panel or hole in which the fastener  10  is mounted. 
     By way of further illustration, the releasable connection between a panel and fastener  10  will provide a desired level of retention force but not enough retention to cause damage to the panel or other material to which the fastener is mounted. For example, the material surrounding a hole in a panel of a 0.8 inch thick sheet of metal might deform if 100 pounds of extraction force is applied. If a specific application requires 50 pounds of retention force, but the w-base fastener requires 120 pounds of force before it will extract from the hole, the panel will become damaged if the 120 pounds of force is exerted on the fastener to remove it from the hole. The invention alleviates this problem by providing a break joint  28  that will be activated at a load between the required load such as 50 pounds and the maximum load such as 100 pounds. 
       FIG. 5  illustrates the position of a portion of the hook and leg, relative to the panel hole edge  37 , after the fastener has been subjected to a load sufficient to separate the fastener at the break joint. Referring to  FIG. 6 , once this break occurs, the separation of the upper portion of the body  22  from the lower portion at break joint  28  will cause the hooks  26  to engage the legs  24  and draw the legs  24  toward the body  22 , thus disengaging the legs from the backside of the panel on which the fastener is mounted. Once in this position, the body  22  and legs  24  will freely pass out of the hole without interference with the panel hole edge  37 . When an extension joint is employed, the fastener  10  can then be reset and reused in the same application, if desired. 
     In use, when the fastener  10  is inserted into a hole formed in a panel, the fastener  10  behaves similar to known w-base fasteners. That is, as shown in the partial view in  FIG. 7  and full side view in  FIG. 9 , the legs  24  flex inward by pressure exerted on the legs by the panel hole edge  37 . After completely passing through the panel hole, the legs  24  flex outward creating interference between the backside of the panel and the legs  24 . The head portion  20   a  will contact the front side of the panel and the combination of the legs  24  contacting the backside of the panel and the head portion  20   a  contacting the front side of the panel secures the fastener to the panel. 
     It should be understood that the secondary connection of the invention is not limited to the panel hole and retaining tab configuration or the use of a break joint. As mentioned above, the fastener  10  may comprise a joint  28  that functions as an extension joint. The function of the extension joint is to both provide separation of the two portions of the fastener  10  to activate the engagement of the hooks  26  with the legs  24 , and to allow the two portions to be reconnected so that the fastener may be reused. The extension joint may be reusable through the employment of a two-part clasp means configured to open upon application of a predetermined load, where one part of the clasp is disposed directly below the extension joint separation point and the other part of the clasp is disposed directly above the extension joint separation point. Any suitable clasp means may be used that will open when subjected to a predetermined force in a non-destructive manner, such that the clasp may be closed again and remain closed until at least the same predetermined load is applied to the clasp. 
     In an embodiment, body  22  further comprises a hollow center containing a separate axial inner portion element. The inner portion element may have an upper end and a lower end, and the lower end may be integrally formed with the interior of body  22 . The upper end, however, may be configured to allow the portion of the fastener  10  above the joint  28  to slide up to the top of the inner portion element, on which is disposed a positive stop. Thus the w-base fastener is prevented from completely separating into two pieces. In an alternate aspect, a hollow portion of body  22  may contain a flexible tether configured to connect the upper and lower portions of fastener  10  as a secondary means to prevent the loss of the w-base end of the fastener during or after extraction from use. Other embodiments and configurations are possible to provide the secondary connection or similar releasable connection and are considered within the scope of the invention. 
     Variations and modifications of the foregoing are within the scope of the present invention. It should be 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.

Technology Classification (CPC): 5