Abstract:
A fastener for mounting objects to a wall or to a floor. The fastener includes an anchor member having an elongate body with a shank portion having a spacer formed integrally with one end, a central longitudinal hole extending through the elongate body, and an internally thread section in the longitudinal hole near a second end of the shank. The shank further includes a deformable expansion region between the first end and the second end of the shank. The fastener further includes a mandrel configured to be received within the longitudinal hole of the elongate body.

Description:
FIELD OF INVENTION  
         [0001]    The present invention relates to thin wall fasteners usable for a variety of purposes. More specifically, the present invention relates to a plug type thin wall fastener assembly utilizing a mandrel and an anchor member. The present invention is particularly suited for seismic restraint purposes and for fastening system applications used in steel stud construction.  
         BACKGROUND OF THE INVENTION  
         [0002]    Mounting an object to a thin wall or floor surface with a hollow space behind the wall or floor (hereafter referred to together as “wall”) is challenging. This is because one can not manually access the space behind the wall, and because the wall itself may not provide sufficient structure to resist the moment of a typical bolt or screw inserted therein once a load is applied to the bolt or screw.  
           [0003]    Some prior art fasteners have attempted to overcome part of this problem by providing a means for expanding a portion of the fastener on the opposite side of the wall to prevent the fastener from pulling out of the hole in the wall into which the fastener has been inserted. Generally the wall is squeezed between a front portion of the fastener and the expanded portion of the fastener. Examples include nut and bolt arrangements, bolt and nut/washer combinations, toggle bolts, and deformable plug fasteners.  
           [0004]    A toggle bolt is a bolt having a spring loaded expandable structure coupled to one end. The expandable structure can be collapsed so that the toggle bolt passes though a hole drilled into a wall. Once the expandable structure has passed through the hole in the wall, the expandable structure springs open. One disadvantage to such fasteners is that removing the bolt allows the expandable portion to fall to the bottom of the hollow space behind the wall. Furthermore, the expandable portion may not provide sufficient resistance to turning of the entire assembly as the bolt is tightened.  
           [0005]    A deformable plug assembly is another type of thin wall fastener. Generally such devices comprise a plug formed as an elongate body having a central longitudinal hole, a top end, a deformable middle section and a threaded portion at the end opposite the top end. When the deformable plug assembly is placed in a hole in the wall, the screw is turned and the threaded portion moves toward the top end. The deformable portion expands to a configuration that is larger than the hole to provide clamping pressure on the back side of the wall. Such devices may include features to enhance rotational resistance to prevent the deformable plug from rotating along with the bolt. However, large fasteners, and fasteners for use with very heavy objects, may require large torquing forces to be applied to set the fasteners, and the large torquing forces required may overcome the rotational resistance features of the prior art, and in addition may crack brittle wall materials.  
           [0006]    In a typical steel stud building, the steel studs will have some wall material placed over the steel studs to form the surface of the wall. A typical floor type used in multistory office buildings consists of concrete laid over sheets of corrugated steel. Prior art fasteners used on such concrete floors may crack the concrete when tightened. Also, the concrete may crack during seismic activity.  
           [0007]    A typical wall material includes dry wall comprising a gypsum material sandwiched between two layers of paper. Prior art fasteners will squeeze the wall material when set, which can crack or crush the wall material, resulting in poorly set fasteners. Furthermore, seismic activity also tends to crack brittle materials such as dry wall and concrete.  
           [0008]    What is needed is a thin wall fastener, a thin wall fastener assembly, and a method of using such thin wall fasteners that overcomes disadvantages of the prior art, that can withstand severe torquing, and that allows a bolt to be removed and replaced for affixing objects to the wall.  
         SUMMARY OF THE INVENTION  
         [0009]    One embodiment of the invention is a thin wall fastener or anchoring apparatus for mounting objects to a thin wall or floor surface (hereafter “wall”). The anchoring apparatus is comprised of a spacer member having means for rotation encompassing an aperture, integral with an open ended cylindrically shaped shank member, integral with an open ended cylindrically shaped clinching member having means for expanding upon being compressed, integral with an open ended cylindrically shaped threaded member having internal threads. The members of the anchoring apparatus share a common central axis.  
           [0010]    In other embodiments, the anchoring apparatus further comprises a mandrel having a head at one end with means suitable for rotation, and a cylindrical shaft extending from the head, the cylindrical shaft having an externally threaded distal end for engaging the internal threads of the anchoring apparatus. Together, the anchoring apparatus and mandrel combine to form a thin wall fastener assembly.  
           [0011]    Additionally, the thin wall fastener assembly may further include a spanner wrench having means for preventing rotation of the anchoring apparatus, while also enabling rotation of the mandrel. 
       
    
    
     DESCRIPTION OF THE DRAWINGS  
       [0012]    [0012]FIG. 1A shows in section an embodiment of the thin wall fastener assembly inserted into a wall and steel stud with the anchor member in an unset state.  
         [0013]    [0013]FIG. 1B shows in section another embodiment of the thin wall fastener assembly inserted into a concrete floor and corrugated steel stud with the anchor member in an unset state.  
         [0014]    [0014]FIG. 2 shows in side view an embodiment of the mandrel.  
         [0015]    [0015]FIG. 3 shows a top view of an embodiment of the mandrel.  
         [0016]    [0016]FIG. 4 shows in section a side view of an embodiment of the anchor member in an unset state.  
         [0017]    [0017]FIG. 5 shows a top view of an embodiment of the anchor member.  
         [0018]    [0018]FIG. 6A shows in section another embodiment of an anchor member inserted into a wall and steel stud with a sleeve to approximate the thickness of the existing wall.  
         [0019]    [0019]FIG. 6B shows in section another preferred embodiment of the anchor member inserted into a concrete floor and corrugated steel stud with a sleeve to approximate the thickness of the existing floor.  
         [0020]    [0020]FIG. 7 shows in section a side view of an embodiment of the anchor member in a set state.  
         [0021]    [0021]FIG. 8 shows a side view of an embodiment of the spanner wrench.  
         [0022]    [0022]FIG. 9 shows a top view of an embodiment of the spanner wrench.  
         [0023]    [0023]FIG. 10A shows in section an embodiment of the thin wall fastener assembly inserted into a wall and steel stud with the anchor member in a set state.  
         [0024]    [0024]FIG. 10B shows in section another preferred embodiment of the thin wall fastener assembly inserted into a concrete floor and corrugated steel stud with the anchor member in a set state. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0025]    The following description is provided to enable any person skilled in the art to make and use the invention and sets forth the best mode presently contemplated by the inventor of carrying out the invention. Various modifications, however, will remain readily apparent to those skilled in the art, as generic principles of the present invention have been defined herein.  
         [0026]    One embodiment of the present invention is a thin wall fastener, and a thin wall fastener assembly, which may be used for a variety of purposes, but particularly for seismic restraint systems in steel stud construction.  
         [0027]    In a typical building, the walls consist of steel studs that will have some wall material placed over the steel studs to form the surface of the wall. A typical wall material includes dry wall comprising a gypsum material sandwiched between two layers of paper. The present invention preferably allows the formation of relatively small holes in the wall material in order to access the steel studs and install the fastener of the present invention.  
         [0028]    The fastener of the present invention does not make contact with the brittle material portions of a wall. Instead, the fastener of the present invention makes contact only with the steel portions of the wall. The other more brittle portions of the wall are removed. The purpose is to create a better fastener, one that does not rely upon brittle wall material for adhesion, instead the fastener only contacts the metal portions of a wall.  
         [0029]    Thin wall fasteners of the present invention are preferably configured so that, when installed, the top surface of the fastener will extend a selected distance from the surface of the steel stud. The purpose is to create a flush surface between the wall and the thin wall fastener. Generally, it is preferred that the selected distance will approximately equal the thickness of the wall material that covers the steel studs, so that the fastener of the invention presents a surface approximately flush with the plane of the wall. However, is some situations it may be preferred that the top of the thin wall fastener of the invention deviate from the plane of the wall.  
         [0030]    In one embodiment, the thin wall fastener of the invention comprises a mandrel and an anchor member. An important characteristic of the fastener is that the anchor member is constructed to expand in snug engagement with the surface surrounding a hole drilled into the steel stud. Also, the fastener is configured to accept a threaded bolt. A second important characteristic of the anchor member is the integral spacer. As previously explained, the height of the spacer may vary, and will typically be selected to accommodate a known thickness of a wall or floor material covering the steel stud.  
         [0031]    In other embodiments the invention further includes a spanner wrench. The spanner wrench engages the spacer to prevent the anchor member from turning during the setting process, without interfering with access to the mandrel.  
         [0032]    Reference will now be made in detail to a presently preferred embodiment of the invention as illustrated in the accompanying drawings. FIG. 1A shows a fastener particularly suited for use in seismic restraint systems in steel stud wall construction. FIG. 1B shows another embodiment of the thin wall fastener for use in floors comprised of corrugated steel studs overlaid with concrete or other flooring materials.  
         [0033]    In a preferred embodiment of the invention seen in FIG. 1A, the fastener assembly  10  comprises a mandrel  20  cooperatively received in an anchor member  30 , and may also include a spanner wrench  40  for engaging the anchor member  30 . FIG. 1A also illustrates the relative position of the steel stud  70  and existing wall  80  in relation to the thin wall fastener assembly  10 .  
         [0034]    [0034]FIG. 1B illustrates the preferred relative position of the corrugated steel stud  75  and overlaid concrete floor  90  in relation to the thin wall fastener assembly  10 .  
         [0035]    Referring to FIG. 2, the mandrel  20  preferably comprises a bolt-like structure capable of setting the anchor member  30  by rotational force. In order to provide sufficient rotational force to set the anchor member  30 , the mandrel  20  preferably comprises a shear resistant material, such as steel, although a variety of materials acceptable for such use are well known.  
         [0036]    As shown in FIGS. 2 and 3, the mandrel  20  preferably includes a hexagonal head  22  at one end, and a shaft  24  extending from the hexagonal head  22 . The hexagonal head  22  is preferably sized to accommodate any standard or metric sized wrench. In alternative embodiments, the head may be any practical shape that can be rotated by a tool such as a wrench, screwdriver, or the like. Preferably, the distal end of the shaft  26  includes an externally threaded section to be cooperatively received by an internally threaded section of the anchor member  30 . Any commercially available thread size may be used.  
         [0037]    Referring to FIG. 4, the anchor member  30  preferably comprises a structure capable of providing seismic restraint when set into a steel stud. To provide the necessary seismic restraint, the anchor member  30  is preferably fabricated from steel or other materials resistant to shearing due to seismic events.  
         [0038]    In a preferred embodiment the anchor member  30  includes a spacer  32  at one end and a shank  34  extending from the spacer  32 . The spacer  32  shown in the preferred embodiment is hexagonal in shape, however, any practical shape of the spacer  32  may be used. Thus, for example, the spacer  32  may be square in shape. The shank  34  shown in the preferred embodiment is cylindrical in shape, although, any practical shape of the shank  34  may be used. The spacer  32  and shank  34  preferably have a bore  36  along their central axis, best seen in FIGS. 4 and 5. The bore  36  in spacer  32  and shank  34  is preferably sized to accommodate the mandrel shaft  24 . It is preferred that the spacer  32  extend above the shank  34  a selected distance, typically sufficient to approximately equal the thickness of any existing wall material  80 . However, many other dimensions of the spacer  32  could be used.  
         [0039]    The anchor member shank  34  preferably includes an internally threaded section  38  at a predetermined distance within the shank  34 . The threaded section  38  is preferably configured for threadably receiving the externally threaded distal end of the shank  26  of the mandrel  20 . The threaded section  38  is preferably at least four thread lengths and capable of receiving at least one additional component once the mandrel  20  is removed. Any variety of components may be secured to the wall, such as braces, shelving, straps or other fasteners to secure various objects to the wall  80 . Although four thread lengths is preferred, any practical number of thread lengths that provide adequate thread contact with the mandrel  20  or the additional component may be used. Any practical thread size may be used, however, small thread sizes may provide insufficient seismic restraint.  
         [0040]    The anchor member shank  34  further comprises a clinching section  50 , positioned between the spacer  32  and the internally threaded section  38 . The clinching section  50  is intended to preferentially deform to set the fastener. The clinching section  50  is preferably a pre-weakened section that collapses when force is applied by the rotation of the mandrel  20 . The clinching section  50  collapses to form an enlargement  60 , as seen in FIG. 7, thus “setting” the thin wall fastener assembly  10 .  
         [0041]    In prototype construction, the clinching section  50  was pre-weakened, by forming the walls of the clinching section somewhat thinner than adjacent sections of the shank. However, any known means for causing the shank to expand preferentially at the clinching section  50  may be used. For example, alternative embodiments of the clinching section  50  may comprise a plurality of parallel slots cut through the shank  34  arranged parallel relative to one another and to the central axis of the shank  34 .  
         [0042]    In some embodiments, a spanner wrench  40  is an included component of the thin wall fastener assembly  10 . Referring to FIGS. 1 and 1A, a spanner wrench  40  engages the spacer  32  to hold the anchor member  30  during the setting process. The engaging section  42  of the spanner wrench  40  preferably extends vertically away from the planar surface of the wrench and is sized and shaped to engage the spacer  32 . The engaging section  42  includes an aperture sized to allow the mandrel head to rotate without hindrance from contacting the spanner wrench  40 . In a preferred embodiment, as seen in FIGS. 8 and 9, the handle  44  of the spanner wrench  40  is angled to allow the user to hold the wrench above the working surface when using the thin wall fastener assembly on large planar surfaces. In the preferred embodiment shown in FIGS. 8, 9, and  10  the engaging section  42  is hexagonal in shape. It is preferable that the engaging section  42  extend from the outer surface of the existing wall to the base of the spacer  32 . However, any practical length of engaging section  42  may be used. It is preferable that engaging section  42  firmly engage the outer surface of the spacer  32 . In some embodiments, each end of the spanner wrench  40  may have a different sized engaging section  42 . However, any practical shape and engaging configuration of the spanner wrench  40  and engaging section  42  may be used.  
         [0043]    In another preferred embodiment as shown in FIG. 6, a sleeve  35  may be used in conjunction with the spacer  32  to approximate the thickness of the existing wall  80 . In another preferred embodiment as shown in FIG. 6A, a sleeve  35  may be used in conjunction with the spacer  32  to approximate the thickness of the existing concrete floor  90 .  
         [0044]    In use on a steel stud thin wall, the fastener  10  of the invention is installed by using a metal detector or stud sensor to locate the steel stud. An appropriately sized hole is drilled through the existing wall  80  and into the steel stud  70 . This first hole should be large enough for the shank  34  of the anchor member  30  to pass through, but not large enough to allow the spacer  32  of the anchor member  30  to pass through. A second larger diameter hole is then drilled in the wall material. The diameter of the second hole is preferably larger than the diameter of the spacer  32 , so that the spanner wrench  40  can be used to hold the anchor member  30  in place while the mandrel  20  is being rotated, as explained below. In alternate methods, the order in which the holes are drilled can be reversed, or the differing diameter sections can be drilled simultaneously. The anchor member  30  is placed into the appropriately sized hole drilled into the steel stud  70 , such that the top surface of the spacer  32  is flush with the existing wall  80 . If the top surface of the spacer  32  is not flush with the existing wall  80 , a sleeve  35  may be used to approximate the thickness of the existing wall  80 , if desired. The spanner wrench  40  is then engaged over the spacer  32  to hold the anchor member  30  in place. Rotational force is then applied to the mandrel head  22  by a wrench, socket, screwdriver, etc., causing the mandrel  20  to threadably engage the anchor member  30 . As clockwise rotational pressure is applied to the mandrel head  22 , the mandrel  20  causes a pulling force onto the anchor member  30 . The pulling force on the anchor member  30  causes the clinching portion  50  to expand as it is compressed, forming an enlargement  60  against the backside of the steel stud  70 . This is best seen in FIG. 10 and in FIG. 10A. The enlargement  60  holds the anchor member  30  in firm contact with the steel stud  70  or corrugated steel stud  75  and inhibits movement of the anchor member. The mandrel  20  is then removed from the anchor member  30  by unscrewing in a counter-clockwise rotation. The spanner wrench  40  is then disengaged from the spacer  32 . The threaded portion  38  is resistant to rotation because the enlargement  60  holds the anchor member  30  in firm contact with the wall or floor.  
         [0045]    The invention is capable of securing at least one additional component to the wall  80  or concrete floor  90 . Any variety of components may be used, such as braces, shelving, straps or other fasteners. The internally threaded portion  38  now acts like a fixed nut. Thus, the mandrel  20  may be used again, along with a washer if desired, for firmly attaching any component to the floor or wall.