Abstract:
A fastener assembly including an internally threaded nut and an externally threaded screw for securing at least two materials together. The screw has an externally threaded shank and an enlarged head. The nut has a shank with a hole therein. The hole is internally threaded to threadingly receive the externally threaded shank of the screw. The nut has a diametrically enlarged head on an end of the shank opposite from an end with an opening of the hole. The enlarged head of the nut has a thickness not exceeding 0.10 inches. The underside of the enlarged head of the nut may have an annular recess formed therein surrounding the shank.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The present invention relates to a fastener assembly, and in particular to a fastener assembly including a nut with an enlarged head and an internally threaded shank. 
         [0002]    Fastener assemblies including a nut with an enlarged encapsulated head have an internally threaded shank comprising a blind hole. The screw is threaded into the hole to secure the two fastener parts together and to clamp the fastened pieces together. These types of fasteners are sometimes referred to as T-nuts. 
         [0003]    In some uses of fastener assemblies, such as in the construction of wall panels for truck bodies, the head of the nut portion of the fastener is exposed on the exterior of the truck. These head portions, which may have a thickness of 0.200 to 0.350 inches from their undersurface to their outer surface, protrude from the otherwise relatively flat wall of the truck, generally in rows or columns when the exterior side wall is secured to the interior wall structure of the truck body. The protruding heads prevent sheet-like advertising or informational signs, such as in the form of truck wraps, from being applied to the exterior side wall of the truck, or else cause a distracting and displeasing appearance. 
         [0004]    Consequently, it can be seen that the need exists for a fastener assembly that can provide an attachment mechanism for truck body exterior side walls, yet will allow for the use of sheet-like advertisements known as full wrap graphics or informational signs to be applied to the exterior side wall without causing a distracting or displeasing appearance. 
       SUMMARY OF THE INVENTION 
       [0005]    In an embodiment, the present invention provides a fastener assembly including an externally threaded screw and an internally threaded nut for use in securing at least two materials together, wherein a head of the nut portion of the fastener assembly has a low profile. This means that the thickness of the head of the nut which protrudes from the exterior surface of the truck body is much thinner than conventional T-nut heads, and is on the order of no greater than about 0.080 to 0.150 inches, and preferably about 0.100 inches. 
         [0006]    The underside of the head of the nut, in an embodiment, includes an annular recess extending around the shank of the nut which results in an annular lip being formed on the lower surface at the circumference of the head. 
         [0007]    A seal member, such as an O-ring, may be carried on the shank of the nut. The seal member will be pressed into the annular recess as the fastener is tightened to provide a water tight seal between the lower surface of the head and the exterior surface of the truck body. This seal member will prevent water, such as rain, from entering the truck body at the location of the fasteners. 
         [0008]    To secure the nut in place in the wall of the truck body, and to prevent rotation of the nut as the screw is tightened into the nut, the nut may be provided with anti-rotation protrusions. These protrusions may take the form of ribs or ridges provided on the shank of the nut. The ribs may be arranged parallel to the axis of the screw which is inserted into the nut, or the ribs may be angled relative to the axis. 
         [0009]    The outer surface of the nut portion of the fastener may be provided with a salt spray protector in the form of a liquid sealant that will dry with a very thin thickness so as not to meaningfully increase the thickness of the head portion. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    The features of the present invention which are believed to be novel, are set forth with particularity in the appended claims. The invention, together with further objects and advantages, may best be understood by reference to the following description taken in conjunction with the accompanying drawings, in the several Figures in which like reference numerals identify like elements, and in which: 
           [0011]      FIG. 1  is a cross-sectional view of a two component wall structure showing the low-profile fastener assembly in place. 
           [0012]      FIG. 2  is a perspective view of a disassembled low-profile fastener assembly. 
           [0013]      FIG. 3  is a side sectional view of the nut portion of the fastener assembly of  FIG. 1 . 
           [0014]      FIG. 4  is a side elevational view of an alternate embodiment of the nut portion of the fastener assembly of  FIG. 2 . 
           [0015]      FIG. 5  is an end elevational view of the nut portion of the fastener assembly of  FIG. 4 , taken from the left side. 
           [0016]      FIG. 6  is a side sectional view of the nut portion of the fastener assembly of  FIG. 5 , taken generally along the line VI-VI. 
           [0017]      FIG. 7  is a perspective view of the nut portion of the fastener assembly of  FIG. 4 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0018]      FIG. 1  illustrates a portion of a structure  10  (such as a container, portable shelter or truck body) in which a material forming a first structural component  12  such as a wall panel is secured to a second structural component  14  such as an extrusion by means of a plurality of fastener assemblies  16 . Although only two layers of structural components are shown, any number of two or greater structural components may be secured together with the fastener assembly  16  of the present invention. 
         [0019]    As shown in  FIGS. 1 and 2 , each of the fastener assemblies  16  includes a first fastener member  18  and a second fastener member  20 . The first fastener member  18  may be in the form of a T-nut which includes a generally disc-shaped head portion  22 . A generally cylindrical shank portion or post  24  is secured to, and extends from, an underside  26  of the head portion  22 . The shank portion  24  may be provided with an anti-rotation structure  28  in the form of a plurality of longitudinal ridges  30 . The longitudinal ridges  30  are formed on a portion of the length of an outer peripheral surface  32  of the shank portion  24 , and extend generally parallel to a longitudinal axis  34  of the shank portion  24 . The longitudinal ridges  30  may have a constant height along their entire length. 
         [0020]    The shank portion  24  is provided with an internally threaded longitudinal bore  36  comprising a blind hole with an opening  38  at a free end  40  opposite the head portion  22 . The outer peripheral surface  32  of the shank portion  24  near the end  40  has a smooth cylindrical shape with an outer diameter smaller than a width dimension of the anti-rotation structure  28 . 
         [0021]    The underside  26  of the first fastener member  18  has an annular recess  46  surrounding the shank portion  24  which forms an annular lip  48  at a periphery  50  of the head portion  22 . When the fastener assembly  16  is tightened into position, a seal member  52  shown in the form of an O-ring which may be carried on the shank portion  24  will be squeezed between the underside  26  of the head portion  22  and the first structural component  12 , which may be the exterior surface of a truck body. In a preferred embodiment, the O-ring  52  has a diameter greater than a depth of the annular recess  46 . For example, the annular recess  46  may have a depth of about 0.025 inches and the O-ring may have a diameter of about 0.0625 inches. This will cause the O-ring to flatten out, as shown in  FIG. 1  when the underside  26  of the head portion  22  presses against the surface of the first structural component  12 . In this manner, water, such as rain, will be prevented from entering the truck body at the location of the fasteners. 
         [0022]    While the underside  26  of the head portion  22  may be made without any recess, if a seal member  52  is used with such a first fastener member  18 , the seal member may be squeezed to the point where it extends beyond the outer periphery of the head portion  22  potentially causing an unsightly appearance. Further, by using an annular recess  46  forming an annular lip  48 , there are two concentric seal points, the lip engagement with the first structural member  12  and the O-ring engagement with the first structural member. This improves the sealing characteristics. 
         [0023]    The second fastener member  20 , which may be a screw, is provided with a generally cylindrical shank portion  60 . The head portion of the screw may be a countersink head, a round head, pan head, etc., depending on the application involved. The shank portion  60  is provided with external threads  62  that may extend along the entire length of the shank portion  60 , and is adapted to threadingly engage with the internal bore  36  of the first fastener member  18 . An outer side of the head portion  56  of the second fastener member  20  may be provided with a recessed portion  64  that is adapted to receive a tool for rotationally driving the second fastener member. The recessed portion  64  as shown is adapted to receive a TORX.RTM. driving tool, but it is contemplated that the head portion  56  can be adapted or shaped to receive any suitable driving tool, such as a screwdriver, allen wrench or socket wrench. 
         [0024]    In  FIGS. 4-7  a second embodiment of the first fastener member is shown at  18 A. This embodiment varies from the embodiment shown in  FIGS. 1-3  in that the ribs  30 A are angled relative to the axis of the shank portion  24 A and the shank portion is relatively shorter than the shank portion  24  shown in  FIGS. 1-3 . In all other respects the construction of the first fastener member  18 A in  FIGS. 4-7  is the same as that shown in  FIGS. 1-3 , namely, there is an annular recess  46  extending around the shank portion  24 A in the undersurface  26 A of the head portion  22 A forming an annular lip  48 A at the periphery  50 A of the head portion. Other similar elements have the same reference number applied as in  FIGS. 1-3 , with the addition of an A suffix. 
         [0025]    In operation, the first fastener member  18  is inserted into a bore  66  in the structural component  12 , as shown in  FIG. 1 . The bore  66  has a diameter that is slightly less than the diameter of the anti-rotational structure  28 . The longitudinal ridges  30  frictionally engage the inner surface of the bore  66 . The smooth cylindrical shape of the outer peripheral surface  32  of the shank portion  24  is smaller in diameter than the bore  66 , allowing the first fastener member  18  to be easily inserted into the bore. 
         [0026]    After the first fastener member  18  has been inserted into the first structural component  12 , the second fastener member  20  is then inserted through an aligned bore  68  in the second structural component  14 , and a driving tool is used to rotationally drive the second fastener member  20 , thus causing the threaded shank portion  60  of the second fastener member to threadingly engage the threaded inner bore  36  of the first fastener member  18 . The frictional engagement of the anti-rotation structure  28  with the inner surface of the bore  68  prevents rotational movement of the first fastener members  18  with respect to the bore  68  of the first structural component  12 . 
         [0027]    The triangular configuration of the longitudinal ridges  30  (see  FIG. 2 ) also allows the first fastener members  18  to be non-destructively removed from the first structural component  12  upon application of a significant axial force. This advantage is particularly important in applications where disassembly and reassembly are required, such as in containers and portable shelters. 
         [0028]    The low profile (thickness) of the head portion  22 ,  22 A results in a nearly smooth surface for the first structural member  12 , thereby allowing the surface of the first structural member to be covered with thin, sheet-like advertisements or informational signs, such as truck wraps, without causing any unsightly bumps at the locations of the fasteners assemblies  16 . The low profile also allows the sheet-like advertisements or informational signs to adhere to the surface of the first structural member without the formation of bubbles or gaps which might detrimentally affect the adherence. 
         [0029]    To provide protection for the first fastener components  18 , they may be coated with a salt spray protector which will seal the surfaces of the first fastener components, and particularly the head portion, from salt spray or other corrosive materials that might lead to rusting or deterioration of the first fastener components. 
         [0030]    The outer surface of the head portion  22 ,  22 A may be painted white or other color, depending on the covering to be placed over the first structural member and the fastener assembly  16  so that if the sheet-like advertisement or informational sign is scraped or torn in the location of the fastener assembly, the fastener assembly will not be readily visible. 
         [0031]    In a particular embodiment, such as shown in  FIGS. 4 and 6 , the first fastener member  18 A may have the following approximate dimensions: Diameter (A) of head  22 A—0.850 inches. Diameter (B) of smooth portion  32 A of shank  24 A—0.335 inches. Length (C) of smooth portion  32 A of shank  24 A—0.135 inches. Axial length (D) of anti-rotational ribs  30 A—0.145 inches. Outer diameter (E) of annular recess  46 A—0.650 inches. Diameter (F) at tops of anti-rotational ribs  30 A—0.375 inches. Thickness (G) of head portion  22 A—0.100 inches. Thickness (H) of head portion  22 A at periphery—0.035 inches. Depth (I) of annular recess  46 A—0.025 inches. Distance (J) from end of anti-rotational ribs  30 A to the underside  26 A of the head portion  18 A—0.010 inches. Threaded recess  36 A sized to receive a ¼ inch—20 threaded screw. 
         [0032]    As is apparent from the foregoing specification, the invention is susceptible of being embodied with various alterations and modifications which may differ particularly from those that have been described in the preceding specification and description. It should be understood that I wish to embody within the scope of the patent warranted hereon all such modifications as reasonably and properly come within the scope of my contribution to the art.