Abstract:
A retaining clip comprising a U-shaped body having a pair of legs that are flexibly connected at their bottom ends and spaced apart to receive therebetween a blade fastener is herein disclosed. Each of the legs of the retaining clip has a head projection that extends laterally from its top end and a cooperating pair of detent structures, each extending laterally from the exterior surface of the respective legs at a predetermined distance below the head projections. Retaining tabs are disposed within and extend inwardly from respective tab apertures formed through each of the legs. These retaining tabs are inclined toward the bottom ends of the legs and are constructed and arranged to easily allow a blade fastener to be inserted therebetween and to subsequently engage the blade fastener to securely retain the blade fastener within the retaining clip. The retaining tabs are constructed and arranged to oppose any forces that would tend to withdraw the blade fastener from the retaining clip substantially in compression.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention is drawn to a retaining clip useful in forming a “blind” connection between a first panel and a second panel.  
         BACKGROUND OF THE INVENTION  
         [0002]    When making a blind connection between a first panel, typically the sheet metal framework of an automobile or the like, and a second panel, often an interior panel of the same automobile, it is well-known to use a simple metal retaining clip that can be received within a window or aperture formed through the first panel and that will engage therein a fastener that extends from an undersurface of the second panel. Such prior art metal retaining clips are deficient in that the abrasive nature of the metal retaining clips often wears through the paint or anticorrosive coatings of the primary panel, thereby promoting corrosion. In addition, metal retaining clips have a distinct tendency to buzz, squeak, and rattle, a condition typically referred to as BSR. In an effort to reduce or eliminate BSR and to prevent corrosion, plastic fasteners have been used to replace the prior art metal retaining clips. Unfortunately, these plastic retaining clips tend to be relatively complex, require complex tooling and molding operations, and have moderately high insertion forces required to seat a blade fastener therein.  
           [0003]    In light of these deficiencies, it would be desirable to provide a retaining clip that may be constructed of non-abrasive materials such as plastic and the like using relatively simple and inexpensive molds and which has a relatively low insertion force.  
         SUMMARY OF THE INVENTION  
         [0004]    The present invention is realized in a retaining clip having a U-shaped body with a pair of legs that are flexibly connected at their bottom ends. These legs are spaced apart sufficiently to receive therebetween a blade fastener that typically extends from the backside of a panel that is to be assembled with yet another panel, such as where the interior panels of an automobile are secured to the framework of the automobile. The retaining clip also has a pair of head projections that extend laterally from the top ends of the respective legs and a pair of detent structures that also extend laterally from exterior surfaces of the respective legs at a predetermined distance from the head projection of each of those legs. Each of the legs of the retaining clip has a tab aperture formed therethrough within which is disposed a retaining tab. These retaining tabs are essentially cantilever structures, are inclined inwardly from the legs of the retaining clip, and may be deflected to permit the blade fastener to be received between the legs of the retaining clip. The tips of the retaining tabs are constructed and arranged to engage an aperture formed through the blade fastener in such a manner as to prevent the withdrawal of the blade fastener from between the legs of the retaining clip. The retaining tabs oppose any forces applied to the blade fastener that would tend to withdraw the blade fastener from within the retaining clip substantially in compression. Note that the hold that the retaining tabs maintain upon the blade fastener exceeds the strength of the hold maintained by the retaining clip on the panel into which it has been inserted. Note also that it is often desirable to be able to withdraw the retaining clip from a window in which it is seated for servicing of the panels that the retaining clip serves to connect. In this case, it may be desirable to include with the retaining clip a pair of support bars that are secured across the respective tab apertures and to the retaining tabs themselves. In this way opposing forces engendered within the retaining tabs are applied to the legs of the retaining clip nearer the bottom of the legs to reduce the outwardly directed component of the opposing forces that acts to secure the retaining clip in a window formed through a first panel.  
           [0005]    The retaining tabs of the retaining clip of the present invention preferably form an acute angle with the blade fastener when the blade fastener has been engaged therein. In addition, the tips of the retaining tabs are constructed and arranged to either engage each other through the aperture formed through the blade fastener or to engage an edge or lip of the aperture formed through the blade fastener itself in order to offset lateral forces applied to the retaining tabs by the blade fastener.  
           [0006]    While the preferred embodiment of the present invention has a single pair of retaining tabs, it is envisioned that the retaining clip may comprise multiple pairs of retaining tabs. In addition, the present invention may be adapted such that the blade fastener has a width much greater than its height. Such a blade fastener may be engaged by a single retaining clip having similar dimensions, or by multiple retaining clips having a single pair of retaining tabs or multiple pairs of retaining tabs. In any case, the magnitude of force required to insert the blade fastener into the retaining clip is relatively low, and typically is about two pounds.  
           [0007]    The present invention may also be characterized as a mechanism for securing together a first and a second panel. This mechanism comprises a retaining clip that has a U-shaped body formed of a pair of legs that are flexibly connected at their bottom ends. The legs are spaced apart from one another sufficiently to receive therebetween a blade fastener that is secured to a second panel. Each of the legs has extending laterally from an exterior surface thereof a head projection and a detent structure. The head projection extends laterally from an upper end of each leg whereas the detent structure is positioned below the head projection a predetermined distance therefrom. Each of the legs also has formed therethrough a tab aperture having disposed therein a retaining tab. Each of the retaining tabs extends from adjacent the head projection inwardly toward the bottom of the legs. These retaining tabs are constructed and arranged to permit the blade fastener of the second panel to be inserted between the legs but to thereafter engage the blade fastener in such a manner that a withdrawal force applied to the blade fastener will be opposed by the retaining tabs substantially in compression. Preferably, these retaining tabs will form an acute angle with the blade fastener as the withdrawal force is applied thereto. In use, the retaining clip is first engaged with the blade fastener and the assembled mechanism is then inserted into a window formed through the second panel to secure the first and second panels together. 
       
    
    
     DESCRIPTION OF THE DRAWINGS  
       [0008]    [0008]FIG. 1 is a perspective view of the retaining clip of the present invention;  
         [0009]    [0009]FIG. 2 is a side elevation of the retaining clip of FIG. 1.  
         [0010]    [0010]FIG. 3 is cut away side elevation of the retaining clip of the present invention taken along cutting lines  3 - 3  shown in FIG. 2;  
         [0011]    [0011]FIG. 4 is a schematic representation of the retaining clip of the present invention shown in relation to a window formed through a first panel and a blade fastener extending from a second panel;  
         [0012]    [0012]FIG. 5 is a partial, schematic view of the retaining clip of the present invention illustrating how the retaining tabs thereof secure a blade fastener therein;  
         [0013]    [0013]FIG. 6 is a side view of an alternate embodiment of the present invention showing a retaining clip with multiple pairs of retaining tabs having retained therein a blade fastener; and,  
         [0014]    [0014]FIG. 7 is a perspective view of an alternate embodiment of the retaining clip of the present invention further comprising support bars secured to the retaining tabs of the retaining clip. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0015]    Although the disclosure hereof is detailed and exact to enable those to practice the invention, the physical embodiments herein disclosed merely exemplify the invention, which may be embodied in other specific structures. While the preferred embodiment has been described, the details may be changed without departing from the invention, which is defined by the claims.  
         [0016]    FIGS.  1 - 3  illustrate a retaining clip  10  of the present invention from various angles. The retaining clip  10  essentially comprises a pair of legs  12  that are resiliently connected at their bottom ends  14  to form a U-shaped body. Each of the legs  12  has extending laterally therefrom at its top end  16  a retaining head  18 . In addition, each of the legs  12  has formed into an exterior surface thereof a detent structure  20 . This detent structure is spaced a predetermined distance d from the undersurface of the retaining heads  18 . As can be seen from the Figures, legs  12  are angled or biased outwardly to form an acute angle with one another.  
         [0017]    Each of the legs  12  has an aperture  22  formed therethrough. While the exact size and shape of the aperture  22  may vary from application to application of the present invention, in a preferred embodiment, the aperture has an upper end that begins at the retaining heads  18  and extends to the bottom  14  of the retaining clip  10 . Within each of the apertures  22  of each leg  12  there exists a retaining tab  24 . The retaining tabs  24  are connected at their base end  26  to the upper surface of the aperture  22  proximate the retaining head  18 . The retaining tabs extend inwardly of the legs  12  into the U-shaped space formed therebetween. It is preferred that the retaining tabs  24  be symmetrical with one another. The tips  28  of each retaining tab may be of any suitable shape, but are preferably provided with at least one sharp edge.  
         [0018]    [0018]FIG. 4 illustrates the retaining clip  10  in relation to a window  32  formed through a first panel  30 . Note that the window  32  is typically rectangular and will have a size that is complementary to that of the retaining clip  10  so that the retaining clip  10  may be inserted and retained therein. Note that the thickness of the first panel  30  will dictate the distance d between the retaining head  18  and the detent structure  20  of each leg  12 . In use, the retaining clip  10  is first engaged with the blade fastener  42 . Once the retaining clip  10  is assembled with the blade fastener  42  as a “part-in-assembly” or PIA, the retaining clip  10  may be inserted into the window  32 . As the retaining clip  10  is inserted into the window  32 , the legs  12  will be biased inward to permit the U-shaped body of the retaining clip  10  to pass therethrough. As the retaining heads  18  of the retaining clip  10  contact the upper surface  34  of the first panel  30 , the resilient structure of the retaining clip will bias the legs  12  outwardly such that the detent structures  20  will engage the undersurface  36  of the first panel  30 .  
         [0019]    As can be appreciated, the detent structure  20  may have many useful shapes; however, it is preferred to form the detent structure  20  into a gradually outwardly extending structure that can accommodate first panels  30  of varying thickness. In general, the thickness of the panel  30  will be the same as or slightly greater than the distance d between the detent structure  20  and the retaining head  18  of the retaining clip  10 . In this manner, the BSR associated with loose retaining clips may be minimized or completely avoided.  
         [0020]    The connection between the first and second panels  30 ,  40  will generally be a blind connection, i.e., the blade fastener  42  and the PIA retaining clip  10  extend from an undersurface  44  of the second panel  40  and cannot be seen by one who is assembling the second panel  40  with the first panel  30 . It is to be understood, however, that the present invention may be adapted for use with structures other than the first and second panels  30 ,  40  that do not require the blind connection described herein. Accordingly, the present invention is not to be limited to only blind connections. In addition, it may also prove useful to assemble first and second panels  30 ,  40  by first inserting the retaining clip  10  into the window  32  in the first panel  30  and subsequently inserting the blade fastener  42  into the retaining clip  10 .  
         [0021]    [0021]FIG. 5 illustrates how the blade fastener  42  is retained within the retaining clip  10  of the present invention. As can be seen, the blade fastener  42  is inserted fully into the U-shaped channel formed between the legs  12  of the retaining clip  10 . Note that the legs  12  are spaced apart sufficiently such that when the retaining clip  10  is received within the window  32  in the first panel  30 , the blade fastener  42  may thereafter be inserted between the legs  12 . Note also that FIG. 5 is a schematic illustration of the present invention and the dimensions and clearances shown are not to be taken as a literal representation of the preferred embodiments.  
         [0022]    As the blade fastener  42  is inserted between the legs  12  of the retaining clip  10 , the retaining tabs  24  will be resiliently biased outwardly by the tip  46  of the blade fastener  42 . When the undersurface  44  of the second panel contacts the upper surface of the retaining heads  18  or is sufficiently close to the retaining heads  18 , the tips  28  of the retaining tabs  24  will return to their first, unbiased position as the aperture  48  formed through the blade fastener  42  is moved into the position illustrated in FIG. 5. The aperture  48  of the blade fastener  42  may be of any suitable size or shape, with the sole requirement being that the aperture  48  must be constructed and arranged to engage the tips  28  of the retaining tabs  24  of the retaining clip  10 . Once the blade fastener  42  is fully seated within the retaining clip  10 , the retaining tabs  24  act to prevent the second panel  40  from being withdrawn therefrom. More specifically, where a withdrawal force indicated by arrow W is applied to the second panel  40 , the retaining tabs  24  will generate opposing forces indicated by arrows F. Whereas the withdrawal force W is directed in a substantially normal direction from the first panel  30  within which the retaining clip  10  is received, the opposing forces F which oppose the withdrawal force W are directed substantially along the length of the retaining tabs  24  and at an acute angle to one another. As can be appreciated, the sum of the vertical components of the opposing forces F engendered within the retaining tabs  24  will balance and counteract the withdrawal force W applied to the second panel  40 . The retaining tabs  24  are further constructed and arranged such that as a result of the withdrawal force W, the tips  28  of the retaining tabs  24  will contact one another such that the horizontal components of the opposing forces F engendered within each of the retaining tabs  24  will oppose one another and cancel each other out. The tips  28  of retaining tabs  24  preferably have formed therein a notch that will engage a lip or edge of the aperture  48 . The tips  28  of the retaining tabs may also have formed therein a vertically aligned flat that allows the tips  28  of the retaining tabs  24  to directly engage one another through the aperture  48 . Yet another embodiment of the retaining tabs  24  has tips  28  having sharp points or surfaces constructed and arranged to engage the surface of the blade fastener  42 . In this embodiment, the blade fastener  42  may comprise an aperture  48 , a roughened or grooved surface (not shown), or at least one relatively soft spot on the tip of the blade fastener  42  that the sharpened tips  28  of the retaining tabs  24  can dig into.  
         [0023]    As the retaining tabs  24  are essentially cantilever structures that extend from the legs  12  of the retaining clip  10  proximate to the retaining heads  18  thereof, the flexible nature of the retaining tabs  24  permits a relatively low insertion force required to insert the blade fastener  42  into the retaining clip  10  of about two pounds. Nevertheless, because the retaining clips  10  are made from a material sufficiently rigid to prevent significant buckling of the retaining members  24 , the retaining tabs  24  will act as a triangular or A-frame structural member that is quite strong. In addition, the hold that the retaining tabs  24  maintain on the blade fastener  42  will be stronger than the hold that retaining clip  10  has on the window  32  formed through the first panel  30 . In this manner it is possible to disassemble the second panel  40  from the first panel  30  without damaging the blade fastener  42  or retaining clip  10 .  
         [0024]    In a preferred embodiment of the present invention, the retaining clip  10  will have a single pair of retaining tabs  24  that engage a single aperture  48  formed in a blade fastener  42 . However, it is to be understood that the retaining clip  10  may comprise any number of retaining tabs  24  as shown in FIG. 6. The retaining tabs  24  of the retaining clip  10  may in turn engage a single aperture  48  formed through a blade fastener  42  or multiple apertures  48  formed through the blade fastener  42  as dictated by the particular application to which the assembly is directed. Furthermore, it is to be understood that while the blade fasteners  42  are herein disclosed as being of approximately the same width as the retaining clips  10 , it is possible that the blade fasteners  42  may extend much wider than their height. For example, a blade fastener  42  may extend the entire length of a panel  40 . As can be appreciated, the window  32  formed in a first panel  30  will be elongated to form a slot that is sized to receive the elongated alternate embodiment of the blade fastener  42 . In this instance, the blade fastener  42  may be provided with a single aperture  48  running the length of the blade fastener  42 , with a single aperture  48  located in a key position along the blade fastener  42 , or with a plurality of apertures  48  located at predetermined locations along the width of the blade fastener  42 . Similarly, the elongate alternate embodiment of the blade fastener  42  may be engaged by a single, elongated retaining clip  10  having a width approaching that of the blade fastener and having multiple pairs of retaining tabs  24  to secure the second panel  40  to a first panel  30 . Alternatively, multiple retaining clips  10  having single pairs of retaining tabs  24  may be inserted into an elongate window  32  that is sized to receive the elongate blade fastener  42  at predetermined positions dictated by the position of the aperture of apertures  48 .  
         [0025]    [0025]FIG. 7 illustrates an alternate embodiment of the present invention that further comprises a pair of support bars  50 . Each support bar  50  is secured to a leg  12  across the tab aperture  48 . The retaining tabs  42  are secured to the support bars  50  so as to transmit opposing forces engendered within the retaining tabs  42  by a withdrawal force directly to the legs nearer the bottom  14  of the legs  12 . This may be particularly useful where the retaining clip  10  is used in metal first panels  30  that have sharp edges around window  32 . The application of the opposing forces to the legs  12  below the head projections/retaining heads  18  reduces the outward forces applied to the legs  12  that cause the legs  12  and particularly the detent structures  20  to strongly engage the sharp edges of the window  32 . This lowers the force required to remove the retaining clip  10  from the window  32  and permits easy access to the panels  30 ,  40  for servicing.  
         [0026]    The foregoing is considered as illustrative only of the principles of the invention. Furthermore, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described. While the preferred embodiment has been described, the details may be changed without departing from the invention, which is defined by the claims.