Patent Publication Number: US-2006000169-A1

Title: Apparatus for protecting metal from treated wood

Description:
BACKGROUND OF THE INVENTION  
      The present disclosure relates to apparatus for protecting metal from treated wood. More particularly, the present disclosure relates to apparatus for protecting metal fasteners and anchors used to couple wood treated with a metal-corrosive preservative to some other structure, such as a concrete foundation.  
      The treated wood industry no longer uses arsenic as a preservative to treat wood. Instead, the treated wood industry now uses chemicals such as, for example, Alkaline Copper Quaternary (ACQ) formulations or Copper Azole (CA) formulations, which can cause destructive galvanic corrosion of untreated metal products such as nuts, bolts, straps, and the like if the untreated metal products come into contact with wood treated with these types of wood treatment formulations. Galvanic corrosion occurs when two dissimilar metals come in direct contact with each other and a small electric current flows between the two metals. In the construction industry, fastener manufacturers have responded to the change in the way in which wood is treated by selling either galvanized or stainless steel components. While such galvanized and stainless steel components resist galvanic corrosion when exposed to the new chemicals used to treat wood, these components are quite expensive when compared to metal fasteners that were used in the past.  
     SUMMARY OF THE INVENTION  
      The present invention comprises one or more of the features recited in the appended claims and/or the following features which, alone or in any combination, may comprise patentable subject matter:  
      A combination may comprise a piece of treated wood that is treated with a substance corrosive to metal, a metal fastener configured to couple the piece of treated wood to a structure, and an apparatus for protecting at least a portion of the metal fastener from the treated wood. The piece of treated wood may be a board, such as a 2-by-4, a 4-by-4, a 2-by-6, or the like. The substance used to treat the wood may be an Alkaline Copper Quaternary (ACQ) formulation or a Copper Azole (CA) formulation. The substance used to treat the wood may be of the type that can cause galvanic corrosion of the metal fastener.  
      The structure may be a building foundation and the metal fastener may comprise an anchor configured to couple the piece of treated wood to the building foundation. The anchor may be configured to couple to cinder blocks of the building foundation. A portion of the anchor may be embedded in a filler material between the cinder blocks. A portion of the anchor may be embedded in a filler material between one of the cinder blocks and a concrete slab of the building foundation. The anchor may be configured to couple to a concrete slab of the building foundation. A portion of the anchor may be embedded in the concrete slab. The piece of treated wood may have an aperture that receives a portion of the metal fastener therein. The metal fastener may have a threaded end that extends upwardly from the foundation. The metal fastener may comprise one or more nuts and/or one or more washers that couple to the threaded end. The piece of treated wood may be situated between the building foundation and the one or more nuts or one or more washers. The structure may be a second piece of treated wood. The metal fastener may comprise a bolt that extends through the first and second pieces of treated wood. The metal fastener may comprise a material other than stainless steel. The metal fastener may comprise a material other than galvanized steel.  
      The apparatus for protecting the metal fastener from the piece of treated wood may comprise a bushing. The apparatus for protecting the metal fastener from the piece of treated wood may comprise an insulator. The bushing may surround a portion of the metal fastener. The bushing may have a first portion that lines, at least in part, an aperture in the piece of treated wood. The bushing may have a second portion situated between one or more nuts and/or one or more washers and the piece of treated wood. The first portion of the bushing may comprise a cylinder and the second portion of the bushing may comprise an annular flange. The annular flange may extend radially outwardly from one end of the cylinder. The bushing may be made from either polypropylene, polyethylene, or NYLON® material, for example. The annular flange and cylinder may comprise a unitary piece. The cylinder may comprise a cylinder wall having substantially uniform wall thickness from a first end to a second end of the cylinder. The annular flange may have substantially uniform thickness from a radially innermost portion of the annular flange to a radially outermost portion of the annular flange. The bushing may be configured such that, when the bushing is placed in an aperture that extends through the piece of treated wood, the annular flange contacts a first planar surface of the piece of treated wood and an end of the cylinder spaced from the annular flange is substantially coplanar with a second planar surface of the piece of treated wood.  
      Additional features, which alone or in combination with any other feature(s), including those listed above and those listed in the claims, may comprise patentable subject matter and will become apparent to those skilled in the art upon consideration of the following detailed description of illustrative embodiments exemplifying the best mode of carrying out the invention as presently perceived. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The detailed description particularly refers to the accompanying figures, in which:  
       FIG. 1  is an exploded perspective view showing a concrete slab, two rows of cinder blocks on the concrete slab, a metal anchor above the cinder blocks, a piece of treated wood having an aperture aligned with a threaded upper end of the anchor, a bushing above the aperture, a pair of washers above the bushing, and a nut above the pair of washer;  
       FIG. 2  is a cross sectional view showing the components of  FIG. 1  in an assembled state having a cylinder of the bushing received in the aperture of the piece of treated wood to prevent the piece of treated wood from contacting the anchor and showing a flange of the bushing preventing a lower washer of the pair of washers from contacting the piece of treated wood;  
       FIG. 3  is a cross sectional view, similar to  FIG. 2 , of an alternative embodiment in which a lower portion of a J-shaped bolt is embedded in a concrete slab and an upper end of the J-shaped bolt has a piece of treated wood coupled thereto by a bushing, a washer, and a pair of nuts;  
       FIG. 4  is a cross sectional view of yet another embodiment, showing first and second pieces of treated wood, each piece of treated wood having an aperture therethrough, a pair of bushings aligned with respective apertures of the pieces of treated wood, a bolt and washer adjacent one of the pair of bushings, and a pair of washers and a nut adjacent the other of the pieces of treated wood; and  
       FIG. 5  is a cross sectional view of the embodiment of  FIG. 4  in an assembled state showing the pair of bushings being configured to prevent contact between the two pieces of treated wood and any of the bolt, the nut, and washers. 
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS  
      An apparatus  10  for protecting a metal fastener  12  from a piece of treated wood  14  is shown in  FIGS. 1 and 2 . The piece of treated wood  14  is treated with a chemical, such as an Alkaline Copper Quaternary (ACQ) formulation or a Copper Azole (CA) formulation, that is corrosive to metal fastener  12  via the mechanism of galvanic corrosion. ACQ formulations are also sometimes referred to as Amine Copper Quaternary formulations. In this disclosure, the acronym ACQ is intended to mean both. These types of wood treatment formulations may contain up to about 40% copper, and possibly more. During the pressure treating process, the wood treatment formulation may impregnate wood  14  thereby giving wood  14  some electrolytic properties. In the past, wood was treated with arsenic which is now illegal (with only a few exceptions) and which contained up to about 2% copper at most. In the example of  FIGS. 1 and 2 , metal fastener  12  is configured to couple the piece of treated wood  14  to a building foundation  16 . Foundation  16  includes at least two rows of cinder blocks  18  supported on a stable underlying structure, such as an illustrative concrete slab  20 .  
      Piece of treated wood  14  has at least one aperture  22  extending therethrough between a first planar surface  24  and a second planar surface  26  of piece of treated wood  14 . Metal fastener  12  extends upwardly from foundation  16  through aperture  22  so that and at least part of a threaded end  28  of fastener  12  projects upwardly beyond surface  24 . Fastener  12  further comprises one or more nuts, such as illustrative hex nut  30 , that couple to threaded end  28  to mount piece of treated wood  14  to foundation  16 . Optionally, one or more washers may be placed on threaded end  28  between nut  30  and apparatus  10 . In the illustrative example, fastener  12  includes a flat washer  32  and a lock washer  34  that are situated on threaded end  28  between nut  30  and apparatus  10 .  
      In the building construction industry, wooden 2-by-4&#39;s and/or 2-by-6&#39;s are typically attached to the building foundation and then the remainder of the building structure is built up from there. In the illustrative example of  FIGS. 1 and 2 , piece of treated wood  14  is a 2-by-4. However, piece of treated wood  14  may be any desired piece of treated wood including, but not limited to, a 2-by-6 or a 4-by-4. In addition, multiple fasteners  12  may be provided for coupling piece of treated wood  14  to foundation  16 . Accordingly, piece of treated wood  14  may have additional apertures therethrough corresponding to the additional number of fasteners used to couple wood  14  to foundation  16 . The description herein of one interconnection between apparatus  10 , fastener  12 , wood  14 , and foundation  16  is applicable to all such interconnections unless specifically noted otherwise.  
      Apparatus  10  is configured to prevent portions of fastener  12  from contacting piece of treated wood  14 . Apparatus  10 , therefore, serves as an insulator between fastener  12  and wood  14 . By preventing contact between fastener  12  and wood  12 , which is treated with a metal-corrosive substance, such as an ACQ or CA formulation, the corrosion of fastener  12  by galvanic corrosion is prevented or substantially inhibited. Illustratively, apparatus  10  is configured as a bushing (sometimes referred to herein as “bushing  10 ”) that has a first portion  36  received in aperture  22  and a second portion  38  sandwiched between planar surface  24  of the piece of treated wood  14  and washer  32  of the metal fastener  12 . Of course, in embodiments having washer  32  omitted, portion  38  is sandwiched between washer  34  and surface  24 , and in embodiments having washers  32 ,  34  omitted, portion  38  is sandwiched between nut  30  and surface  24 .  
      While bushing  10  may be made of any material having the galvanic corrosion inhibiting characteristics described herein, in most embodiments, bushing  10  may be made from any suitable plastic material, such as polyethylene, polypropylene, or NYLON® material, for example. As such, first and second portions  36 ,  38  of bushing  10  may be formed integrally with one another. Portion  28  rests upon surface  24  of wood  14  and first portion  36  extends from second portion  38  substantially all the way through aperture  22 . However, in the illustrative example, portion  36  does not project beyond planar surface  26 , but rather an annular end surface  40  of portion  36  is substantially coplanar with surface  26  as shown in  FIG. 2 . If desired, bushing  10  may be sized so that annular end surface  40  is positioned within aperture  22  at a location part way between surfaces  24 ,  26 . In most embodiments, however, portion  36  will extend more than half way through aperture  22 .  
      Illustratively, first portion  36  of bushing  10  is cylindrical in shape and second portion  38  comprises a disk-like annular flange that extends radially outwardly from an upper end of portion  36  as shown in  FIGS. 1 and 2 . Bushing  10  has a cylindrical bore  42  that extends axially therethrough. In the illustrative embodiment, the thickness of the cylindrical wall defined by portion  36  beneath portion  38  is substantially uniform at all locations along the axial length of portion  36 . In addition, the disk-like annular flange of portion  38  has a substantially uniform thickness at all location radially outward of portion  36 . In alternative embodiments, these thicknesses may vary such as, for example, in embodiments in which portion  36  is tapered, has axially extending splines (internal and/or external), is threaded (internal and/or external), is stepped in configuration, or is serrated in some manner, and in embodiments in which portion  38  is tapered or countersunk in some manner, has radially extending splines or protrusions (above or below the remainder of portion  38 ), has other types of protrusions (above or below the remainder of portion  38 ), or is stepped in configuration.  
      Portion  36  may have either a loose fit or tight fit within aperture  22 , as desired. In addition, fastener  12  may have either a loose fit or tight fit within bore  42  of bushing  10 . In the illustrative example, portion  36  has a loose fit in aperture and fastener  12  has a loose fit within bore  42  for ease of assembly. Also in the illustrative example, the diameters of the outer peripheries of washers  32 ,  34  are smaller than the diameter of the outer periphery of portion  38  of bushing  10 . Thus, no portion of washers  32 ,  34  extends radially beyond the outer periphery of portion  38 . In addition, illustrative nut  30  is dimensioned such that no portion of nut  30  extends radially beyond the outer periphery of portion  38  of bushing  10 . In alternative embodiments, some portion of any one or more of washers  32 ,  34  and nut  30  may extend beyond the outer periphery of portion  38  yet still be maintained out of contact with piece of treated wood  14  by portion  38  of bushing  10 .  
      Metal fastener  12  is sometimes referred to in the construction industry as an anchor. Accordingly metal fastener  12  is sometimes referred to herein as “metal anchor  12 ” or simply “anchor  12 .” Anchor  12  has a lower C-shaped portion  44  and an upstanding portion  46  that extends upwardly from C-shaped portion  44  as shown in  FIGS. 1 and 2 . Portion  44  includes a lower horizontal segment  48 , a vertical segment  50 , and an upper horizontal segment  52 . Portion  46  includes threaded end  28  and a vertical segment  54  which interconnects threaded end  28  with upper segment  52 . Segments  48 ,  50 ,  52 ,  54  are each generally flat strips of material and threaded end  28  is swaged or otherwise formed into the configuration of threaded end  28 . In the illustrative embodiment segments  48 ,  50 ,  52 ,  54  and threaded end  28  of anchor  12  are made integrally with each other from a single piece of metal strip. In alternative embodiments, anchor  12  may be made from multiple pieces which are coupled together.  
      Each cinder block  18  has two rectangular walls  56  which are vertically oriented and three connection walls  58  which are also vertically oriented as shown in  FIG. 1 . Walls  58  interconnect walls  56  and are spaced apart so as to define two openings  60  which extend vertically through the associated cinder block  18  and which have generally square-shaped cross section. Each wall  56  has a thickness dimension  62  and a height dimension  64  as shown in  FIG. 1 . Segments  48 ,  52  of anchor  12  have approximately the same lengths as thickness dimension  62  and segment  50  is slightly longer than height dimension  64 . As shown best in  FIG. 2 , C-shaped portion  44  of anchor  12  surrounds three surfaces of wall  56  of one of cinder blocks  18  such that segment  48  is situated beneath the associated wall  56 , segment  50  abuts (or is in close proximity with) an outwardly facing surface of the associated wall  56 , and segment  52  is above the associated wall  56 . Segment  54  extends upwardly from segment  52  through opening  60  of the associated concrete block  18  and abuts (or is in close proximity with) an inwardly facing surface of the associated wall  56 .  
      Segment  48  is embedded in a filler material  66  provided between concrete slab  20  and the lower one of the two cinder blocks  18  shown in  FIG. 2 . Segment  52  is embedded in filler material  66  provided between the upper and lower cinder blocks  18  shown in  FIG. 2 . In alternative foundation arrangements, additional rows of concrete blocks  18  may be provided between the two illustrative rows of concrete blocks  18  and concrete slab  20 , it being understood that, in such arrangements, anchor  12  would be associated with the upper two rows of concrete blocks  18  so that threaded end  28  projects upwardly beyond the uppermost row of concrete blocks  18 . Thus, the concrete blocks  18  adjacent anchor  12  and the associated filler material  66  prevent anchor  12  from moving relative to foundation  16 .  
      Because bushing  10  prevents contact between fastener  12  and piece of treated wood  14 , fastener  12  does not need to be made from galvanized or stainless steel. Instead, fastener  12  may be made from less expensive grades of metal which would otherwise corrode in an unacceptable manner by the mechanism of galvanic corrosion if contact between such metal and wood  14  were to occur. Thus, use of bushings  10  in building construction provides a substantial cost savings compared to using galvanized or stainless steel fasteners.  
      Referring now to  FIG. 3 , an alternative foundation  76  and an alternative metal fastener  72  are shown. Elements of the embodiment shown in  FIG. 3  which are substantially similar, or the same, as elements of the embodiment of  FIGS. 1 and 2  are denoted by like reference numerals. Accordingly, the description above regarding such elements having like reference numerals, and alternatives thereof, is applicable to the embodiment shown in  FIG. 3  unless specifically noted otherwise.  
      Foundation  76  comprises a concrete slab  20  having an upper surface  70  upon which surface  26  of piece of treated wood  14  rests. Fastener  72  is sometimes referred to in the construction industry as a J-bolt. Accordingly, fastener  72  is sometimes referred to herein as “J-bolt  72 ” or “J-shaped bolt  72 .” J-bolt  72  has a lower portion  74  which includes a bend or elbow  78 . Lower portion  74  is embedded in concrete slab  20 . J-bolt  72  includes an upper portion  80  that extends vertically upwardly from lower portion  74  and that projects beyond upper surface  70  of concrete slab  20 . In addition, upper portion  74  of J-shaped bolt  72  has a threaded end  82  that extends beyond upper surface  24  of piece of treated wood  14 . In the illustrative example, fastener  72  includes nut  30  and flat washer  32  which are mounted on threaded end  82 , but fastener  72  also includes a jam nut  84  mounted on threaded end  82  above nut  32 .  
      Bushing  10  prevents any portion of fastener  72 , including upper portion  80 , nuts  30 ,  84 , and washer  32  from contacting piece of treated wood  14 . Thus, fastener  72  does not need to be made from galvanized steel or stainless steel, but rather may be made from less expensive grades of metal which would otherwise corrode in an unacceptable manner by galvanic corrosion if contact between such metal and wood  14  were to occur. According to this disclosure, therefore, a metal fastener may be protected against a metal-corrosive substance used to treat wood by the use of illustrative bushing  10 , and its alternatives described herein, regardless of the configuration of the metal fastener, regardless of the configuration of the piece of treated wood, and regardless of the structure (such as foundations  16 ,  76 ) to which the piece of treated wood is coupled.  
      Referring now to  FIGS. 4 and 5 , piece of treated wood  14  is mounted to a second piece of treated wood  86  by a metal fastener  88 . In the illustrative example, piece of treated wood  86  is a 4-by-4 board. However, any two pieces of treated wood may be coupled together in accordance with the teachings of this disclosure. While the types of structures having pieces of treated wood coupled together are innumerable, a few examples of such structures include decks, porches, piers, playground equipment, barns, storage sheds, and roller coasters. Elements of the embodiment shown in  FIGS. 4 and 5  which are substantially similar, or the same, as elements of the embodiment of  FIGS. 1 and 2  are denoted by like reference numerals. Accordingly, the description above regarding such elements having like reference numerals, and alternatives thereof, is applicable to the embodiment shown in  FIGS. 4 and 5  unless specifically noted otherwise.  
      Illustrative fastener  88  comprises an elongated bolt having a hex head  90  and an elongated shaft  92  with a threaded end  94 . Second piece of treated wood  86  has a first planar surface  96 , a second planar surface  98 , and an aperture  100  extending therethrough between surfaces  96 ,  98 . As was the case with first piece of treated wood  14 , second piece of treated wood  86  is treated with a chemical, such as an ACQ formulation or a CA formulation, that is corrosive to metal. Thus, a second apparatus  110  for protecting metal fastener  88  from second piece of treated wood  86  is provided. Apparatus  10 , therefore, serves as an insulator between fastener  88  and wood  86 .  
      Illustratively, apparatus  110  is configured as a bushing (sometimes referred to herein as “bushing  110 ”) that is shaped similarly to bushing  10 . Accordingly, bushing  110  has a first portion  112  received in aperture  100  and a second portion  114  sandwiched between planar surface  96  of the piece of treated wood  86  and a washer  116  of the metal fastener  88 . Of course, in embodiments having washer  116  omitted, portion  114  is sandwiched between hex head  90  and surface  96 . While portion  114  of bushing  110  is substantially the same in size and configuration as portion  38  of bushing  10 , portion  112  of bushing  110  is much longer than portion  36  of bushing  10  so as to accommodate the increased distance between surfaces  96 ,  98  of wood  86  as compared to the distance between surfaces  24 ,  26  of wood  14 .  
      As was the case with bushing  10 , bushing  110  may be made from any suitable plastic material and may be formed integrally with one another. Portion  114  abuts surface  96  of wood  86  and first portion  112  extends from second portion  114  substantially all the way through aperture  100 . However, in the illustrative example, portion  112  does not project beyond planar surface  98 , but rather an annular end surface  118  of portion  112  is substantially coplanar with surface  98  as shown in  FIG. 5 . If desired, bushing  110  may be sized so that annular end surface  118  is positioned within aperture  100  at a location part way between surfaces  96 ,  98 . In most embodiments, however, portion  112  will extend more than half way through aperture  100 . In the illustrative embodiment, only a minimal amount clearance is provided between end surface  118  of bushing  110  and end surface  40  of bushing  10 . The clearance between end surfaces  40 ,  118  of bushings  10 ,  110 , respectively, allows fastener  88  to tightly clamp pieces of wood  14 ,  86  together without interference from bushings  10 ,  110 .  
      Illustratively, first portion  112  of bushing  110  is cylindrical in shape and second portion  114  comprises a disk-like annular flange that extends radially outwardly from an one end of portion  112  as shown in  FIGS. 4 and 5 . Bushing  110  has a cylindrical bore  120  that extends axially therethrough. The description above of alternative shapes and configurations of bushing  10  is equally applicable to bushing  110 . Portion  112  may have either a loose fit or tight fit within aperture  100 , as desired, and fastener  88  may have either a loose fit or tight fit within bore  120  of bushing  110 . In the illustrative example, loose fits are provided for ease of assembly. Fastener  88  extends through bores  42 ,  120  of bushings  10 ,  110 , respectively, so that threaded end  94  extends beyond portion  38  of bushing  10 . Thus, nut  30  and washers  32 ,  34  of fastener  88  may be mounted on the portion of threaded end  94  that projects beyond bushing  10 .  
      Although certain illustrative embodiments have been described in detail above, variations and modifications exist within the scope and spirit of this disclosure as described and as defined in the following claims.