Patent Publication Number: US-2007116537-A1

Title: Push-back fastener

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
      This application claims priority to and all the benefits of U.S. Provisional Patent Application Ser. No. 60/734,625, filed Nov. 8, 2005 and entitled “Push-back Fastener.” 
    
    
     BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The invention relates to a fastener for attaching a first member to a second member. More particularly, the invention relates to a fastener engaging opposing sides of a base member to attach the base member to an attachment member.  
      2. Description of Related Art  
      Push-in fasteners are often used in the automotive industry to secure two members together. Such push-in fasteners typically include a head and a shank having at least one resilient fin which deforms to allow insertion of the shank through an aperture in the members. Once the fin passes through the apertures, the fin springs or bounces back to its original position to prevent the fastener from being pulled back out through the apertures. Thus, the at least one fin retains the shank within the aperture of the member.  
      One common push-in fastener is referred to as a Christmas Tree fastener. Such Christmas Tree fasteners typically utilize a plurality of axially spaced apart and parallel fins positioned along a shank. Another common push-in fastener is referred to as an arrow fastener and includes a deformable arrow-shaped member at one end of a shank. The deformable arrow-shaped member deforms upon insertion of the fastener through one or more apertures. The arrow-shaped member does not allow the fastener to be pulled back out of the apertures without destroying the fastener. Each of the afore-mentioned push-in fasteners have a common drawback—they engage only one side of a member. This results in excessive rattling and an inability to control the position of the attachment to the member after installation.  
     SUMMARY OF THE INVENTION  
      According to one aspect of the invention, a fastener is provided for attaching a first member to a second member. The fastener includes a head and a shank having a first end abutting the head and an opposing second end. An entry guide extends out from the second end of the shank for guiding the fastener into engagement with the second member. An alignment rod extends out from the entry guide for aligning the fastener with the second member. The fastener also includes at least one wing extending out from the shank for engaging the second member and urging the second member into constant engagement with the entry guide. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:  
       FIG. 1  is a perspective view of a fastener according to one embodiment of the invention;  
       FIG. 2  is a cross-sectional view of the fastener fixedly securing an attachment member to a base member;  
       FIG. 3  is a cross-sectional view of the fastener integrally formed with the attachment member for joining the base member thereto; and  
       FIG. 4  is a fragmentary, perspective view of a fastener according to a second embodiment of the invention integrally formed with an attachment member. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      Referring to  FIGS. 1 and 2 , a fastener, generally shown at  10 , according to one embodiment of the invention is utilized to attach at least one first member  12  to a second member  14 . Preferably, the first member  12  is an attachment member and the second member  14  is a base member. The base member  14  includes a first side  16  and an opposing second side  18 . The base member  14  defines a base aperture  20  extending from the first side  16  through the second side  18 . The fastener  10  extends through the base aperture  20  to join the attachment member  12  to the base member  14 .  
      The fastener  10  includes a head  22  and a shank  24  extending out therefrom. The shank  24  includes a first end  26  abutting the head  22 , and an opposing second end  28 . The shank  24  has a length extending between the first  26  and second  28  ends. The particular length of the shank  24  may vary. Preferably, the cross-section of the shank  24  is circular. It is, however, appreciated that the shank  24  may have any of a variety of cross-sectional shapes.  
      An entry guide  30  is located at the second end  28  of the shank  24  to aid insertion of the fastener  10  into the base aperture  20  of the base member  14 . The entry guide  30  preferably has a conical shape and extends between a wide end  32  and an opposing pointed end  34 . The wide end  32  and the pointed end  34  each have a width. The width of the wide end  32  is greater than the width of the pointed end  34 . Moreover, the width of the wide end  32  of the entry guide  30  is also greater than a width of the shank  24 . An alignment rod  35  extends out from the pointed end  34  of the entry guide  30 . Together, the entry guide  30  and the alignment rod  35  align the fastener  10  with the base aperture  20 .  
      The fastener  10  further includes a pair of wings  36 ,  38  spaced apart from the entry guide  30  and extending out from the shank  24  at a location between the wide  32  and pointed  34  ends thereof. Each of the pair of wings  36 ,  38  terminates at a distal end  40  spaced away from the shank  24 . In addition, each of the pair of wings  36 ,  38  is attached to the shank  24  such that the pair of wings  36 ,  38  extends outwardly therefrom in an angular fashion. More specifically, each of the pair of wings  36 ,  38  extends outwardly and downwardly towards the entry guide  30 . The pair of wings  36 ,  38  is formed from a flexible material that allows the pair of wings  36 ,  38  to flex towards the head  22  of the fastener  10  as the fastener  10  is being installed. A channel  42  is formed adjacent the shank  24  between the pair of wings  36 ,  38  and the entry guide  30 .  
      The fastener  10  further includes a hollow interior portion  44  extending generally from the first end  26  of the shank  24  into the entry guide  30 . The hollow interior portion  44  allows inward deformation of the entry guide  30  to facilitate insertion of the fastener  10  through the base aperture  20  of the base member  14 .  
      The fastener  10  may be formed from any of numerous materials. Preferably, the fastener  10  is formed from a plastic material due to its strength, cost-effectiveness, and ability to withstand distortion. Materials such as polypropylene, polyethylene, and nylon are particularly suitable for the fastener  10 .  
      It is appreciated that although the fastener  10  and at least one attachment member  12  have been set forth as separate components, the fastener  10  may be integrally formed with the attachment member  12 , as shown in  FIG. 3 .  
      In operation, to attach the attachment member  12  to the base member  14 , the fastener  10 , with the attachment member  12  secured thereto, is first aligned with the base aperture  20  by way of the entry guide  30  and the alignment rod  35 . The fastener  10  is then pushed through the base aperture  20  until the wide end  32  of the entry guide  30  clears the second side  18  of the base member  14 . The base aperture  20  has a width that is less than the width of the wide end  32  of the entry guide  30 . Thus, the entry guide  30  temporarily deforms in order to allow passage thereof through the base aperture  20 . Such deformation of the entry guide  30  is facilitated by the hollow interior portion  44  of the fastener  10 . Once the entry guide  30  passes through the base aperture  20 , the wide end  32  of the entry guide  30  abuts the second side  18  of the base member  14  to prevent the fastener  10  from being pulled back through the base aperture  20 , thereby attaching the attachment member  12  to the base member  14 . When the fastener  10  is fully installed, the distal end  40  of each of the pair of wings  36 ,  38  engages the first side  16  of the base member  14  to urge the base member  14  into constant engagement with the wide end  32  of the entry guide  30 . The ability of the wings  36 ,  38  to flex accommodates base members  14  of varying widths and tolerance variations.  
      The engagement of the wings  36 ,  38  pushing against the first side  16  of the base member  14  urges the second side  18  of the base member  14  against the wide end  32  of the entry guide  30  to retain the base member  14  in a tight fit between the wings  36 ,  38  and entry guide  30 , thereby eliminating rattle that would be otherwise produced by the vertical shifting of the base member  14  along the shank  24  between the first  26  and second  28  ends thereof. This engagement also improves the ability to control the position of the attachment member  12  after installation of the fastener  10  and improves the retention of the attachment member  12  to the base member  14 .  
      Referring to  FIG. 4 , wherein like primed reference numerals represent similar elements as those described above, the fastener  10 ′ in a second embodiment of the invention is integrally formed with the attachment member  12 ′ and includes a pair of spaced apart, flexible legs  52 ,  54  extending out therefrom. The pair of spaced apart legs  52 ,  54  defines an elongated opening  55  therebetween. Each of the spaced apart legs  52 ,  54  extends between a connecting end  56  abutting the attachment member  12 ′ and an opposing distal free end  58 . The legs  52 ,  54  are interconnected generally midway between the ends  56 ,  58  by a center bridge  60 . The portion of each leg  52 ,  54  extending from the center bridge  60  to the distal free end  58  forms a respective flexible finger  62 ,  64 . The flexible fingers  62 ,  64  form an entry guide that is received within and through the base aperture  20 ′ formed in the base member  14 ′. The flexible fingers  62 ,  64  deform inwardly to facilitate insertion of the fastener  10 ′ into the base aperture  20 ′ of the base member  14 ′.  
      The fastener  10 ′ includes the alignment rod  35 ′ extending out from the center bridge  60 . The alignment rod  35 ′ terminates at a leading end  68  which extends beyond the distal free end  58  of each of the pair of spaced apart legs  52 ,  54  for aligning the fastener  10 ′ with the base aperture  20 ′ formed in the base member  14 ′.  
      Each of the spaced apart legs  52 ,  54  flares outwardly from the distal free end  58  thereof to a respective abutment wall  70 ,  72 . The abutment walls  70 ,  72  have a diametrical width that is greater than a diameter or width of the base aperture  14 ′ of the base member  12 ′.  
      Each of the spaced apart legs  52 ,  54  also includes one of the pair of flexible wings  36 ′,  38 ′ extending out therefrom. More specifically, each of the pair of wings  36 ′,  38 ′ extends laterally outwardly from each leg  52 ,  54  toward the distal free end  58  thereof. A channel  42 ′ is defined by the pair of wings  36 ′,  38 ′ and the abutment walls  70 ,  72  alongside each leg  52 ,  54  for receiving and retaining the base member  14 ′. It is appreciated that the installation of the fastener  10 ′ to join the attachment member  12 ′ to the base member  14 ′ proceeds in the same manner as the above-described first embodiment of the invention with the wings  36 ′,  38 ′ engaging the first side  16 ′ of the base member  14 ′ and urging the second side  18 ′ of the base member  14 ′ against the abutment walls  70 ,  72 .  
      One skilled in the art will appreciate that many modifications of the fastener  10  are possible. For example, the entry guide  30  could, instead of having a conical shape, be an additional set of wings that angle upwards towards the head  22  of the fastener  10 . As another example, the entry guide  30  could include one or more relatively flexible fins integrally formed at the second end  28  of the shank  24  such that, upon insertion of the fastener  10  through the base aperture  20 , the fins would flex towards the head  22  and successively engage the second side  18  of the base member  14  to connect the attachment member  12  to the base member  14 . In yet another example, the wings  36 ,  38  may include one or more disc-shaped fins extending around a perimeter of the shank  24  to form a flexible rib therealong.  
      The invention has been described in an illustrative manner. It is to be understood that the terminology, which has been used, is intended to be in the nature of words of description rather than of limitation. Many modifications and variations of the invention are possible in light of the above teachings. Therefore, within the scope of the appended claims, the invention may be practiced other than as specifically described.