Abstract:
A railing system for porches, decks, steps, ramps and the like having a top and bottom rail formed of wood containing a wood preservative that is corrosive to aluminum, aluminum alloys and the like. The system has hollow metal balusters formed of metals which may be harmed by the corrosive effects of the wood preservative. The metal balusters are protected from the corrosive effects of the wood preservative by inert fixtures interposed between the wooden components of the railing system and the metal of the balusters. The fixtures may be joined by runners that simplify installation of the railing system.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to railings made with treated lumber and metal balusters wherein the balusters are isolated from corrosion by the lumber. 
   2. Brief Description of the Prior Art 
   It has been found that an attractive fence or railing resembling a wrought iron fence can be made with hollow metal balusters mounted in holes drilled in top and bottom wooden rails. One such construction is described in our earlier patent (U.S. Pat. No. 6,394,422 to Jones et al.) incorporated by reference herein. 
   In recent years there has been a change in the chemicals employed for treating lumber used in an outdoor environment. Arsenic, the primary component used to preserve wood from deterioration, has been eliminated. To compensate for the lack of arsenic, the amount of copper containing chemicals impregnated into the wood has been greatly increased. The increased copper content has caused the metal balusters, when formed of aluminum, to corrode, especially at the point of contact with the wood. The problem of corrosion is increased in the outdoor environment where the components are exposed to moisture, i.e., from rain, dew and other sources. 
   U.S. Pat. Nos. 1,797,883, 3,810,341, 4,403,767, 4,886,245, 5,419,538, 5,474,395, 6,126,148, 6,305,670, 6,308,937, 6,311,957, and 6,394,422 are incorporated by reference herein. 
   BRIEF SUMMARY OF THE INVENTION 
   The present invention provides a method and structure for rapid and inexpensive construction of railing having balusters formed of metal tubes. The balusters may be made of metal, such as aluminum, aluminum alloys and like materials. 
   The invention provides a structure which protects the balusters from the corrosive effects of wood treated with copper containing wood preservatives and the like. In a preferred embodiment of the invention a noncorrosive fixture provides a barrier flange positioned between the baluster tube and a supporting rail. 
   A further embodiment adds an installation guide mechanism which assists in rapidly positioning an array of fixtures on a supporting rail for rapid installation of the balusters. This mechanism eliminates the need for time consuming hand measuring and layout of the fixtures. 
   It is thus an object of this invention to provide a railing system which may be easily and rapidly constructed from pressure treated wood rails and metal balusters. It is another object to provide a railing system in which the metal balusters are protected from corrosion by the wooden rails. Other objects and features of the invention will be in part apparent and in part pointed out hereinafter. 
   The invention summarized above comprises the constructions hereinafter described, the scope of the invention being indicated by the subjoined claims. 

   
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
     In the accompanying drawings, in which several of various possible embodiments of the invention are illustrated, corresponding reference characters refer to corresponding parts throughout the several views of the drawings in which: 
       FIG. 1  is an exploded perspective view of a railing in accordance with the present invention; 
       FIG. 2  is a broken view of a detail of the invention; 
       FIG. 3  is a cross-sectional view taken along the plane  3 — 3  in  FIG. 2 ; 
       FIG. 4  is a perspective view of a fixture of the invention; 
       FIG. 5  is a top plan view of a joined array of fixtures such as that shown in  FIG. 4 ; 
       FIG. 6  is an exploded side view of an alternative railing according to the invention; 
       FIG. 7  is a cross-sectional view taken along the plane  7 — 7  in  FIG. 6 ; 
       FIG. 8  is a detail in side elevation and on an enlarged scale of two fixtures of the array shown in  FIG. 5 ; and, 
       FIG. 8A  is a detail in further enlarged scale taken along line A—A in  FIG. 8 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring to  FIG. 1 , a section of railing  10  according to the invention is shown. Railing  10  has a horizontal top rail  12  and a horizontal bottom rail  14  with a plurality of balusters  16  placed between the top and bottom rails  14 ,  16 . Balusters  16  may be made from straight sections of round aluminum tubing, but is will be appreciated that they may be made from another material, such as another metal, and may have a different cross-section and/or a more complex shape. 
   Balusters  16  are installed on rails  12  and  14  using fixtures  18  of the invention. Fixtures  18  are installed on bottom rail  14  using screws  20 , as shown in  FIGS. 2 and 3 . Fixtures  18  are installed at appropriate intervals along bottom rail  14 , as shown in  FIG. 1 , and balusters  16  are placed over fixtures  18  with fixtures  18  snugly received in the bottoms of balusters  16 . Fixtures  18  are also installed along top rail  14  at matching intervals and top rail  14  lowered to place its fixtures  18  snugly into the tops of balusters  16 , as shown. 
   As shown in  FIGS. 2 ,  3  and  4 , fixtures  18  have a hollow body  22  with an exterior  24  shaped to conform to in inner configuration of balusters  16  and tapered for snug force fit entry therein. Exterior  24  is shown as having a round cross-sectional shape for round balusters  16  of  FIG. 1 , but may be of a variety of cross-sections such as square, rectangular, oval or the like to match balusters  16  having other internal and external configurations. 
   With continuing reference to  FIG. 4 , fixtures  18  may have a plurality of longitudinal ribs  26  thereon. Ribs  26  assist in providing a snug fit between balusters  16  and fixtures  18 . As shown in  FIGS. 3 and 4 , fixtures  18  may be hollow having a central cavity  28  therein. Central cavity  28  may terminate in an opening  30  at the bottom of fixtures  18 . Fasteners, such as screws  20  or other fasteners, may be received in central cavity  28  and extend through opening  30  which forms a collar through which the shank of fastener  20  passes to join fixtures  18  to upper and lower rails  12 ,  14 . Opening  30  includes an abutment shoulder  31  against which the head of fastener  20  is stopped. As shown in  FIG. 2 , screws  20  may be readily installed using a power driver  32 . 
   Referring to  FIGS. 3 ,  4  and  8 , fixtures  18  are provided with a flange  34  at the terminus of fixtures  18 , as shown. Flange  34  acts as a stop against which balusters  16  are seated, when received therein, and spaces balusters  16  from rails  12  or  14  on which balusters  16  are installed. In place, flange  34  of fixture  18  acts as a corrosion barrier by keeping balusters  16  out of contact with rails  12  and  14  which may contain a corrosive wood preservative. 
   Referring to  FIGS. 6 and 7 , an alternative embodiment is shown. A second fixture  36  may be used with an inclined top rail  38  and an inclined bottom rail  40 , as shown. Fixture  36  may have an inclined bottom surface  42  to match the angle of inclination of top rail  38  and bottom rail  40 . Inclined top rail  38  and bottom rail  40  are typically installed along steps or ramps, as is known in the art. Balusters  16  may be installed using fixtures  36 , as shown in  FIGS. 6 and 7 . Typically, balusters  16  will extend vertically, even though top rail  38  and bottom rail  40  are inclined to the vertical. 
   Fixtures  36  may have a central cavity  44 , similar to central cavity  28  described above. Central cavity  44  may also terminate in an opening  46 , similar to opening  30  described above. Fasteners, such as screws  20  may be received through central cavity  44  and opening  46  to join fixtures  36  to upper and lower rails  38 ,  40 , as shown in  FIGS. 6 and 7 . Balusters  16 , shown in phantom in  FIG. 7 , may be installed in upper rail  38  and lower rail  40  as described above. 
   Fixtures  36  also may have flanges, such as circumferential flanges  48 , which act as a stop for balusters  16  and space balusters  16  from upper rail  38  and lower rail  40 . When so installed, flanges  48  of fixtures  36  provide a corrosion barrier by keeping balusters  16  out of contact with wood which may contain a corrosive preservative. 
   Fixtures  18  and  36  may be fabricated from a variety of conventional material. Nonconductive ceramics, glass, rubber compounds and plastics may be used. Preferred materials are the conventional chemically inert or corrosion resistant polymers such as polyethylenes, polypropylenes, vinyl polymers, polyamidenylon polymers, polyethers and polyesters, including mixtures and copolymers thereof. These materials are strong, durable and inexpensive and possess the preferred balance of flexibility and rigidity. It has been found that if sufficiently elastic polymers are used a single embodiment of fixture  36  may be used for railings placed at a range of angles of inclination. The flexibility of the elastomer provides sufficient compliance to allow fixture  36  to distort to conform to the angle of inclination of upper rail  38  and lower rail  40 . The compliance may be enhanced by providing transverse grooves, not shown, in bottom surface  42  of fixture  36 , if desired. 
     FIGS. 5 and 8  show an alternative embodiment of fixtures  18  or  36  arranged as an array  49 . By using an injection moldable polymer, such as an injection moldable polyethylene, array  49  of fixtures  18  can be molded as a unit. Fixtures  18  are joined by runners  50  formed of thin strips of polymer which are molded with the fixtures  18 . Runners  50  can be sized in length to space fixtures  18  or  36  to provide the appropriate spacing for balusters  16 , for example runners  50  can provide a spacing of 4.5 inches between adjacent balusters  16 . By using runners  50  to provide the spacing between adjacent balusters  16  on top rail  12  and bottom rail  14 , railing  10  can be constructed in a minimum of time since the step of hand laying out the location of the fixtures  18  can be eliminated. 
   Runners may be provided with weakened areas  51  adjacent to fixtures  18 ,  36 , as shown in  FIGS. 5 and 8 , spaced above flanges  34 ,  48 , respectively. When the installation of fixtures  18 ,  36  on runners  50  has been completed, balusters  16  sever weakened areas  51  as the balusters are installed over fixtures  18 ,  36  such that runners  50  may be removed and discarded. 
   While fixtures  18 ,  36  were originally developed for use with wooden rails treated with preservatives, the fixtures may be used with untreated wood such as cedar or with synthetic materials. With these materials, fixtures  18 ,  36  provide for easy assembly of a railing system because the rails need not be drilled to receive balusters  16 . This is a significant advantage in the case of synthetic materials which may be soft and weakened by drilling. It will therefore be understood that fixtures used with rails which do not corrode the metal balusters are within the claims to the fixtures. 
   In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained. As various changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.