Abstract:
A fastener and washer assembly wherein the washer includes a central planar bearing portion, an opening through the bearing portion, end portions inclined from a plane of the planar bearing portion and elongated openings on opposed sides of the central opening and a fastener having a body portion and a radial flange portion received in the elongated openings, rotatably supporting the fastener on the washer. The method of assembly includes driving the radial flange portion of the fastener against at least one of the inclined end portions of the washer, resiliently biasing the end portion outwardly and receiving the radial flange portion in the elongated openings.

Description:
RELATED APPLICATIONS  
       [0001]    This application claims priority to U.S. Provisional application Ser. No. 60/451,558 filed Mar. 3, 2003. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    This invention relates to a fastener and washer assembly and method of forming same, wherein the fastener may rotate relative to the washer, but the washer is retained on the fastener.  
         BACKGROUND OF THE INVENTION  
         [0003]    There are many applications which require a washer located between the head or body of the fastener and a substrate to which the fastener is threadably attached, particularly including mass production applications such as automotive applications, where a torque wrench is used to thread the fastener. At present, a washer may be manually placed between the substrate and the fastener head or body in such applications. However, manual placement of a washer requires a separate step which may also be difficult in certain applications. Alternatively, there are nut and washer assemblies available on the market, wherein the washer is rotatably supported on a specially designed nut in a groove in an annular body portion of the nut. A fastener and washer assembly including a washer and bolt assembly utilizing a conventional nut or bolt would, however, be more desirable, particularly from a cost standpoint.  
           [0004]    Another problem associated with a fastener and washer assembly, wherein the fastener is rotatably supported on the washer, is that the fastener and washer may have different strength or hardness requirements. For example, the fastener may require heat treatment or a special protective coating and the washer may preferably be formed from a softer metal or without a protective coating. Thus, it would desirable to form the washer and fastener assembly after heat treatment or application of a protective coating to the fastener.  
           [0005]    The fastener and washer assembly of this invention achieves these advantages or objects including the use of a conventional nut or bolt and may be assembled after heat treatment or coating of the fastener.  
         SUMMARY OF THE INVENTION  
         [0006]    The fastener and washer assembly of this invention may include a conventional nut or bolt particularly, but not exclusively, including a conventional commercially available flange nut or flange bolt having a frustoconical flange or skirt portion, thereby significantly reducing the cost. Further, the fastener and washer assembly of this invention may be assembled after heat treatment or application of a protective coating on the fastener.  
           [0007]    The fastener and washer assembly of this invention includes a conventional fastener, such as a conventional flange bolt or flange nut, and a washer rotatably supported on the fastener. The washer includes a central flat or planar bearing portion having an opening therethrough and opposed upwardly angled end portions or ears on opposed sides of the bearing portion each having an elongated opening extending generally perpendicular to the axis of the opening through the central planar portion which receive the flange or skirt portion of the nut or bolt. The ears are preferably angled relative to the planar bearing portion at an angle of less than 90 degrees, preferably between 30 and 85 degrees, and more preferably between 40 and 80 degrees. The ears may also be bowed outwardly to permit greater movement of the washer relative to the fastener for alignment purposes.  
           [0008]    The method of assembling the fastener and washer assembly of this invention includes forming a flat generally rectangular washer having a central opening and elongated generally parallel openings on opposed sides of the central opening. The ear portions are then formed by bending the plate adjacent the juncture of the elongated openings at an angle of less than 90 degrees or preferably between 30 and 85 degrees, such that the openings are aligned with the flat central bearing portion of the washer.  
           [0009]    The fastener, such as a conventional flange nut or flange bolt, is then assembled on the washer by driving the flange or skirt portion of the nut or bolt against at least one of the upwardly angled ear portions and snapped in place. Thus, the method of assembling a fastener and washer assembly of this invention may also include pretreatment of the fastener, such as heat treatment or application of a protective coating. In the one preferred embodiment of the washer, the elongated slots on opposed sides of the central opening include an arcuate or semi-circular inner wall providing additional bearing support for the fastener and providing semi-circular surfaces which support a conventional flange nut or flange bolt, but permits lateral movement toward and away from the end portions.  
           [0010]    In a preferred embodiment of the fastener and washer assembly, the fastener includes a polygonal body portion and a frustoconical radial flange portion integral and coaxially aligned with the polygonal body portion. Where the fastener is a female fastener or nut, the female fastener includes a bore through the polygonal body portion and the frustoconical flange portion which may internally threaded as required. Where the fastener is a male fastener, such as a stud, the male fastener may include a shank portion integral with the radial flange portion which may be externally threaded as required. As described above, the washer assembled on the fastener includes a planar bearing portion having a central opening, preferably a cylindrical opening, and generally parallel openings or slots on opposed sides of the central opening equally spaced from the central opening and inclined end portions or ears on opposed ends of the planar bearing portion, wherein the ears are bent upwardly from the planar bearing portion through the slot to receive the frustoconical radial flange portion of the fastener through the slots during assembly. In a preferred embodiment, the inner wall of the elongated slots adjacent the central opening is semi-circular providing full bearing support for the circular radial flange portion of the fastener. Thus, the washer is rotatably supported on the fastener and the fastener can freely rotate relative to the washer during threaded attachment of the fastener. As will be understood, a female fastener will normally be threaded onto a male fastener typically located on the other side of a substrate, such as a bracket or other part. Similarly, a male fastener, such as a bolt, will typically be threaded into a female fastener, such as a nut, again typically on the opposite side of the substrate, such that the washer will bear against the substrate during threading of the fastener.  
           [0011]    As will be understood by those skilled in this art, various modifications may be made to the disclosed embodiments of the washer, fastener and washer and fastener assembly within the purview of the appended claims. The embodiments of the fastener and washer assembly and method of forming a fastener and washer assembly disclosed herein are for illustrative purposes only.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]    [0012]FIG. 1A is a top view of one embodiment of a washer blank prior to forming the ears;  
         [0013]    [0013]FIG. 1B is a top view of an alternative embodiment of a washer blank;  
         [0014]    [0014]FIG. 2A is a top view of the washer blank shown in FIG. 1A following forming of the ears from the blank;  
         [0015]    [0015]FIG. 2B is a side view of the washer after forming the ears from the blank shown in FIG. 1B;  
         [0016]    [0016]FIG. 3 is a perspective view of the washer shown in FIG. 2A;  
         [0017]    [0017]FIG. 4 is an end view of one embodiment of a nut and washer assembly of this invention;  
         [0018]    [0018]FIG. 5 is a top view of the nut and washer assembly shown in FIG. 4;  
         [0019]    [0019]FIG. 6 is a side view of the nut and washer assembly shown in FIGS. 4 and 5;  
         [0020]    [0020]FIG. 7 is a perspective view of the nut and washer assembly shown in FIGS.  4  to  6 ;  
         [0021]    [0021]FIG. 8 is a side view of the nut and washer assembly shown in FIGS.  4  to  7  during assembly of the nut and washer assembly;  
         [0022]    [0022]FIG. 9 is a side view of one embodiment of a bolt and washer assembly of this invention;  
         [0023]    [0023]FIG. 10 is a top view of the bolt and washer assembly shown in FIG. 9;  
         [0024]    [0024]FIG. 11 is a side view of FIG. 10;  
         [0025]    [0025]FIG. 12 is a perspective view of the bolt and washer assembly shown in FIGS.  9  to  11 ; and  
         [0026]    [0026]FIG. 13 is a side view of the bolt and washer assembly shown in FIG. 11 during assembly of the washer on the bolt illustrating the method of assembly. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0027]    [0027]FIG. 1A illustrates one preferred embodiment of a flat rectangular washer blank  20 B having linear or planar side faces  22  and linear or planar end faces  24 . The rectangular washer blank  20 B further includes a central circular opening  26  spaced generally equally between the side faces  22  and the end faces  24 . The washer blank  20 B also includes elongated generally parallel openings or slots  28  on opposed sides of the central opening  26  adjacent the side faces  24  equally spaced from the central opening  26  and extending perpendicular to the axis of the central opening  26 . In this embodiment, the elongated openings  28  each include a curvilinear inner side wall  30 , which are generally semi-circular, providing a flat generally circular bearing face  34  as described further below. The elongated openings  28  in this embodiment may also include linear outer side walls  32 . The embodiment of the washer blank  120 B in FIG. 1B is also generally rectangular and includes linear side faces  122 , but the end faces  124  are curvilinear or generally semi-circular each having an axis coincident with the circular center opening  126 , such that the elongated openings  128  on opposed sides of the central opening  126  are also generally semi-circular having a curvilinear or generally circular inner side wall  132  and a generally semi-circular outer side wall  132 . That is, the nut blank  120 B in FIG. 1B is similar to the nut blank  20 B shown in FIG. 1A except that the end faces  124  are generally semi-circular and the elongated openings  128  are also semi-circular.  
         [0028]    [0028]FIGS. 2A and 3 illustrate the washer  20  after forming the ears on washer blank  20 B shown in FIG. 1A. As shown in FIG. 2A, the end faces  24  have been deformed upwardly at an angle relative to the flat bearing face  34  of less than 90 degrees and preferably between 30 and 85 degrees, or more preferably between 40 and 80 degrees. As best shown in FIG. 3, the end portions  36  are bent upwardly about a linear axis  38  which is generally coincident with the ends of the semi-circular inner side walls  30 , such that the generally circular bearing face  34  remains flat. The washer  120  is similarly formed, such that the end portions  136  are planar and deformed upwardly at an angle of less than 90 degrees relative to the bearing face  134 , as described above in regard to FIG. 2A, except that the end faces  124  are generally semi-circular as described above in regard to FIG. 1B.  
         [0029]    FIGS.  4  to  7  illustrate a nut and washer assembly of this invention, wherein the washer  20  is assembled on a conventional flange nut  40 . As will be understood by those skilled in this art, a conventional flange nut  40  includes a body portion  42  having a polygonal outer surface  44 , typically hexagonal, as shown, or octagonal, a threaded opening  46  and a radial flange or skirt portion  48  having a frustoconical outer surface  50  and a circular or cylindrical rim portion  52 . Although the fastener and washer assembly of this invention is not limited to a conventional flange nut or flange bolt (shown in FIGS.  9  to  13 ), one important object of this invention is to utilize a conventional nut or bolt of the type commonly used in mass production applications, such as the automotive industry, to reduce costs and to meet the existing specifications of such manufacturers.  
         [0030]    As shown in FIG. 8, the washer  20  is assembled on the flange nut  40  by receiving the radial flange or skirt portion  48  into one of the elongated openings  28  and the radial flange portion is then snapped into the opposed elongated opening  28  by a force shown by arrow P which may be applied by hand or preferably by a press. As set forth above, the female fastener and washer assembly shown in FIGS.  4  to  7  will typically be threaded on a male fastener which extends through an opening in a substrate, such as a bracket, wherein the washer  20  is supported on the substrate and the nut is threaded on a threaded portion of a male fastener (not shown). Similarly, the bolt and washer assembly shown in FIGS.  9  to  12  described below is typically received through an opening in a substrate and a nut or other female fastener is threaded onto the end of the bolt, wherein the washer  20  is received against the substrate. Upon assembly, the central opening  26  of the washer  20  may be coaxially aligned with the threaded opening  46  of the washer  20 , as shown in FIG. 6, and the flange nut  40  is free to rotate relative to the washer. The radial flange or skirt portion  48  of the nut  40  is received on the flat semi-circular bearing surface  34  of the washer  20 , shown in FIGS. 2A and 3, providing an enlarged bearing area which fully supports the radial skirt or flange portion  48  of the nut  40 . The flange nut  40  is also free to move laterally toward and away from the upwardly angled end or ear portions  36  because the slots formed by the elongated openings  28  have a width greater than the minor diameter of the frustoconical outer surface  50 .  
         [0031]    FIGS.  9  to  12  illustrate a bolt and washer assembly of this invention, wherein the washer  20  is assembled on a conventional flange bolt  54 . As will also be understood by those skilled in this art, a conventional flange bolt  54  includes an elongated shank portion  56 , which is typically externally threaded as shown at  58 , and a head portion  60 , which is substantially identical to the flange nut  40  described above. That is, the head portion  60  includes a polygonal outer surface  62  and a radial flange or skirt portion  64 . The skirt portion  64  typically includes a frustoconical surface  66  and a circular or cylindrical rim portion  68 . As described above with regard to FIG. 8, the washer  20  is assembled on the flange bolt  54  by driving the skirt portion  66  as shown by arrow P, which snaps the skirt portion  66  into the elongated openings  28  of the washer. That is, the force P causes the angled end portions  36  to spread or deflect radially outwardly, receiving the flange portion  66  into the elongated openings  28 . In this embodiment, the shank portion  56  is first received through the central opening  26  prior to snapping the washer  20  on the flange bolt  54 . The semi-circular flat bearing surface  34  shown in FIGS. 2A and 3 similarly supports the radial flange or skirt portions  64  as described above.  
         [0032]    As will be understood by those skilled in this art, a conventional or typical flange nut is formed of carbon steel, such as ASTM A563M, which is typically heat treated. A conventional flange bolt is also generally formed of steel, such as ASTM F568M or SAE J1199 and heat treated to Rockwell 42 to 48. The flange nut or flange bolt may then be coated with a protective coating, such as a zinc coating or a black oxide. A flange nut or flange bolt is then threaded onto a bolt in the nut and washer assembly of this invention or into a threaded opening in the bolt and washer assembly of this invention. In mass production applications, the fastener is typically threaded using a conventional torque wrench set at about 1370 in./lbs. With the method of forming a fastener and washer assembly of this invention, the flange nut or flange bolt may be heat treated and coated to the manufacturer&#39;s specifications and then assembled on the washer of this invention by simply snapping the washer in place as described above. However, the fastener will freely rotate on the washer following assembly. As will now be understood, the inclination of the end portions  36  of the washer is preferably less than 90 degrees to permit the washer to be snapped on the fastener. However, the angle of inclination should be greater than 40 degrees and less than 90 degrees to assure that the washer remains on the fastener and the washer may be snapped in place on the fastener.  
         [0033]    Having described preferred embodiments of the fastener and washer assembly and a method of assembly, it will be understood by those skilled in this art that various modifications may be made within the purview of the appended claims. For example, end portions  36  may be bowed outwardly as shown in phantom at  36 A in FIG. 2A to provide greater clearance. Further, the opening  26  may be elongated toward the end faces  24  to accommodate misalignment. The washer may also be welded to the substrate by providing conventional weldable dimples (not shown) on the flat bearing portion opposite the fastener preferably adjacent the end faces. The washer  20  is preferably formed of steel, such as SAE 1050 or 1065, but is preferably not heat treated.