Abstract:
In accordance with the disclosed principles, a novel thermoplastic profile roofing strip and an apparatus for welding the thermoplastic profile roofing strip to a thermoplastic roofing membrane is disclosed. In one embodiment, the thermoplastic profile roofing strip may comprise a horizontal base extending longitudinally and having a notched profile. In addition, the thermoplastic profile strip may comprise a vertical central portion laterally connected at one edge and normal to the horizontal base. In such embodiments, the vertical central portion extends longitudinally along the horizontal base to provide the improved profile. Related methods of welding a thermoplastic strip to a thermoplastic membrane are also disclosed.

Description:
TECHNICAL FIELD 
     In accordance with the disclosed principles, a decorative roof profile and a method for attaching same to thermoplastic roofing membranes, more particularly welding a thermoplastic decorative profile to a thermoplastic single ply membrane is disclosed. 
     BACKGROUND 
     Thermoplastic roofing membranes, such as polyvinyl chloride (PVC) and thermoplastic polyolefin (TPO), are rapidly growing in market acceptance. However, even though they can be made in a wide variety of colors, they do not impart a good aesthetic appearance to a roof surface. In contrast, metal roofing has regular, parallel standing seams that join each sheet of metal. These seams, together with colored metal coatings, provide for an attractive roofing surface. In fact, metal roofing is frequently used as a decorative and functional roof surface for small commercial and public building roof sections that are visible from the street. Some plastic profile systems are available for attachment to thermoplastic roofing membranes, such that a metal roof-like appearance can be obtained. These profile systems are sometimes described as standing seam profiles (SSP). 
     To duplicate this appearance, thermoplastic strips have been secured to the thermoplastic membranes, sometimes by adhesive, and sometimes by the application of heat, all of which is done manually. An example of an adhesive system is a butyl peel and stick tape. Adhesive systems may require the roof membrane be primed prior to attachment, with difficulty being priming the exact area of attachment. Primer that extends onto the roofing membrane may be visible and discolor the membrane. Another disadvantage of adhesively attached profiles is that adhesive systems may not be as robust for the 20 to 30 year life expectancy of the roof system as compared to a permanent attachment method. 
     Applying heat to permanently attach the profiles may require a welder that is large and cumbersome. For a steep sloped roof, this is especially challenging. Also, the roofer will be required to guide the system in a straight line to achieve a good appearance, while keeping the profile in place, and maintaining a balance on a sloped roof. 
     Unfortunately, manual application of the strips is a time consuming and labor intensive process, increasing the cost of the roofing and decreasing the cost advantage gained by selecting thermoplastic roofing over metal roofing. Manual application also increases opportunity for error and is not conducive to creating straight and/or parallel and/or equidistant lines. What is needed in the art is a quick and inexpensive apparatus and method of attaching thermoplastic strips to thermoplastic roofing membranes. 
     SUMMARY 
     Embodiments of the invention provide a thermoplastic profile strip and a welding apparatus for permanently attaching the profile strip to a thermoplastic roofing material. In addition, methods for welding a thermoplastic profile strip to a thermoplastic membrane are also disclosed. 
     In one aspect, an improved thermoplastic profile strip is disclosed. In one embodiment of such a strip, the thermoplastic profile roofing strip may comprise a horizontal base extending longitudinally and having a notched profile. In addition, the thermoplastic profile strip may comprise a vertical central portion laterally connected at one edge and normal to the horizontal base. In such embodiments, the vertical central portion extends longitudinally along the horizontal base to provide the improved profile. 
     In another aspect, an apparatus for welding a thermoplastic profile strip to a thermoplastic membrane is provided. In one embodiment, such an apparatus may comprise a first nozzle capable of directing hot air onto an upper surface of a first edge of a thermoplastic profile strip, and a second nozzle capable of directing hot air onto an upper surface of a second edge of a thermoplastic profile strip. In addition, in such an embodiment, the apparatus may also comprise a tubular splitter capable of simultaneously supplying hot air to the first nozzle and the second nozzle. In more specific embodiments, the first and second nozzles each comprise a first portion for supplying hot air and a second portion configured to apply downward pressure on upper surfaces of the strip that have received hot air. 
     In yet another aspect, methods for welding a thermoplastic profile strip to a thermoplastic membrane are provided. In one embodiment, such a method may comprise placing a thermoplastic profile roofing strip onto a thermoplastic roofing membrane. Such a thermoplastic profile roofing strip may include a horizontal base extending longitudinally having a notched profile, and a vertical central portion laterally connected along one edge to the horizontal base, wherein the vertical central portion extends longitudinally along the horizontal base. In such an embodiment, the method may also include applying an apparatus for welding a thermoplastic profile strip to a thermoplastic roofing membrane. The method may then comprise splitting a supply of hot air to first and second nozzles, and simultaneously directing hot air onto upper surfaces of a first and second lips of the thermoplastic profile strip using the first and second nozzles. In addition, the method could then comprise advancing the apparatus along the length of the thermoplastic profile strip such that the first and second nozzles simultaneously supply the split hot air along the length of the thermoplastic profile strip. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a cross-sectional view of a thermoplastic profile strip to be welded to a thermoplastic roofing membrane. 
         FIG. 2  is a perspective view of an alternate embodiment of a thermoplastic profile strip. 
         FIG. 3A  is a side view of a welder attachment for attaching a thermoplastic profile strip to a thermoplastic roofing membrane. 
         FIG. 3B  is a front view of the welder attachment of  FIG. 3A . 
         FIG. 3B  is a detailed view of embodiments of the nozzle tips of  FIG. 3A  conjoined for use with the welding apparatus of  FIG. 2 . 
     
    
    
     DETAILED DESCRIPTION 
     A thermoplastic profile strip  100  as shown in  FIG. 1 . The profile strip  100  may be attached to a thermoplastic roofing membrane in accordance with the disclosed principles. The thermoplastic profile strip  100  is preferably produced as an integrally formed seamless thermoplastic object. Methods of production of the thermoplastic profile strip  100  may include extrusion, molding, etc. The thermoplastic profile strip  100  preferably includes an upstanding central portion  105  extending lengthwise along the strip and opposed flange portions  110  extending widthwise from the central portion  105 . In some embodiments, the opposed flange portions  110  extend from the central portion  105  in the range from about 0.5 inch to about 1 inch, and in a preferred embodiment may be about ⅝ inch. The opposed flange portions  110  length may depend on the height of the upstanding central portion  105  that needs to be supported. 
     In some embodiments, the upstanding central portion  105  height ranges from about 1 inch to about 3 inches, more preferably from about 2 inches to about 2.5 inches. In a preferred embodiment, the upstanding central portion  105  height is 1.25 inches. Opposite the upstanding central portion  105  and the opposed flange portions  110  is a bottom surface  115 . In a preferred embodiment, the bottom surface  115  is about ¾ inch. In alternate embodiments, the bottom surface  115  may range from about ⅛ inch to about 1 inch. In some embodiments, the bottom surface  115  may be coated with an adhesive. In some embodiments, the bottom surface  115  may be coated with a pressure sensitive adhesive and  125  a release liner  130 . In some embodiments, the adhesive  125  may be, but not limited to, butyl rubber adhesive and the release liner  130  may be, but not limited to, siliconized paper. 
     The upper portion of the upstanding central portion  105  includes an integral hook  135 . In a preferred embodiment, the hook  135  has a cross section similar to an upside down U. In an alternate embodiment, the hook  135  may also include a lip. In alternate embodiments, the hook  135  may be any cross sectional shape capable of being a guide or used with a lock as described below. 
     In an alternate embodiment, the thermoplastic profile strip  100  may have a triangular cross-sectional shape as seen in  FIG. 2 . The opposed flange portions  110  may include a notched profile. The profile would extend along the length of both of the opposed flange portions  110 . The notched profile may be any shape, such as a square tooth (as shown) or saw toothed and the like. During continuous welding, the notched profile may enable the teeth to be heated along with sections of the thermoplastic roofing membrane. The welder foot may then “smear” the teeth out over the heated thermoplastic roofing membrane ensuring a good weld. 
     Embodiments of an apparatus  300  for welding the thermoplastic profile strip  100  to the thermoplastic roofing membrane are shown in  FIGS. 3A-3B . Like numerals are used across the figures to describe similar parts of the apparatus  300 . In a preferred embodiment, the apparatus  300  includes a first nozzle  400 A, a second nozzle  400 B, a platform guiding device  500 , and a splitter  600 . In addition, other embodiments of a welding apparatus that may be employed with the profile strips of the present disclosure may be found in co-pending U.S. application Ser. No. 12/651,331, which was filed the same day as the present disclosure, and is commonly owned with the present disclosure and incorporated herein by reference in its entirety. 
       FIG. 3A  is a side view of the apparatus  300  and  FIG. 3B  is a front view of the apparatus  300  connected to the first nozzle  400 A and the second nozzle  400 B. In a preferred embodiment, the first nozzle  400 A and the second nozzle  400 B are identical and only the first nozzle  400 A will be described. The splitter  600  supplies hot air to the first nozzle  400 A and the second nozzle  400 B. The splitter  600  includes an inlet  610  and a plurality of outlets  620 . In a preferred embodiment, the splitter  600  is fabricated from pipe components, i.e., fittings. In an alternate embodiment, the splitter  600  is an integrally fabricated piping component. The sizing of the splitter  600  including the inlet  610  and the plurality of outlets  620  will be dependent on the sizing of the first nozzle  400 A and the second nozzle  400 B, which will be sized dependent on the thermoplastic profile strip  100 . The splitter  600  will be connected to a hot air supply (not shown), preferably a hot air gun. In an alternate embodiment, the apparatus  300  may only include a first nozzle  400 A. 
     The first nozzle  400 A includes an inlet  405  and a tip  410 . The inlet  405  will be connected to one of the outlets  620  of the splitter  600 . The tip  410  includes an outlet for delivering a hot air stream to the edge of the opposed flange portions  110 . In an alternate embodiment, the tip  410  is shaped to be placed on the notched profile of the opposed flange portions  110 . The cross section of the first tip  410  is preferably shaped to provide an even flow of hot air across the notched profile. Moreover, the elongated pointed profile of the tip  410  allows heat to be applied from a back portion of the tip  410 , while the front end of the tip  410  continues to apply downward pressure to the welding area as the tip  410  is moved along the profile strip  100 . 
     As shown in  FIG. 3B , the platform guiding device  500  is capable of moving the splitter  600 , first nozzle  400 A, second nozzle  400 B along the length of the upstanding central portion  105  of the thermoplastic profile strip  100 . In some embodiments, the platform guiding device  500  may be self-propelled while in other embodiments the platform guiding device  500  may be manually propelled by an operator. In a preferred embodiment, the platform guiding device  500  includes a platform  505  and a guide  510 . In a preferred embodiment, the platform  505  is capable of supporting the hot air supply and associated parts. The platform  505  may be shaped and sized by one of skill in the art to support the platform  505 , the guide  510 , and associated parts. 
     To ensure the hot air and pressure are applied to the welding area, the guide  510  travels along the upstanding central portion  105  of the thermoplastic profile strip  100 . In a preferred embodiment, the guide  510  is an upside down U in cross section sized to be placed over the thermoplastic profile strip  100 , preferably the hook  135 . The guide  510  may also include a guide roller. In some embodiments, the guide roller is sized to control the elevation of the platform guiding device  300 . In some embodiments, the guide roller is a silicon roller. In alternate embodiments, the guide roller may be made of any hard rubber with a smooth surface. In some embodiments, the guide  510  also includes a locking device. The locking device is shaped and sized to connect with the hook  135  of the thermoplastic profile strip  100 . In some embodiments, the locking device is a movable platform having a first position for providing access to place the guide  510  on the upstanding central portion  105  and a second position to place the movable platform in contact with the hook  135  of the thermoplastic profile strip  100 . In alternate embodiments, the guide  510  has a cross section for mounting on the cross sectional profile of the thermoplastic profile strip  100 . 
     Before the thermoplastic profile strip  100  is welded to the thermoplastic roofing membrane, the thermoplastic profile strip  100  may be temporarily attached to the thermoplastic roofing membrane in straight parallel lines using the adhesive  125  and release liner  130 . In operation, the first nozzle  400 A and the second nozzle  400 B are positioned as shown in  FIG. 3B . The first nozzle  400 A and the second nozzle  400 B preferably drag over the teeth and are long enough that they cover several teeth simultaneously. As the platform guiding device  500  moves along the upstanding central portion  105  of the thermoplastic profile strip  100 , jets of hot air from the first nozzle  400 A and the second nozzle  400 B weld the notches to the thermoplastic roofing membrane  200 . The tip  410  may then “smear” the notched teeth out over the heated thermoplastic roofing membrane ensuring a good weld. 
     While a number of particular embodiments of the present invention have been described herein, it is understood that various changes, additions, modifications, and adaptations may be made without departing from the scope of the present invention, as set forth in the following claims. 
     Additionally, the section headings herein are provided for consistency with the suggestions under 37 C.F.R. 1.77 or otherwise to provide organizational cues. These headings shall not limit or characterize the invention(s) set out in any claims that may issue from this disclosure. Specifically and by way of example, although the headings refer to a “Technical Field,” such claims should not be limited by the language chosen under this heading to describe the so-called technical field. Further, a description of a technology in the “Background” is not to be construed as an admission that technology is prior art to any invention(s) in this disclosure. Neither is the “Summary” to be considered as a characterization of the invention(s) set forth in issued claims. Furthermore, any reference in this disclosure to “invention” in the singular should not be used to argue that there is only a single point of novelty in this disclosure. Multiple inventions may be set forth according to the limitations of the multiple claims issuing from this disclosure, and such claims accordingly define the invention(s), and their equivalents, that are protected thereby. In all instances, the scope of such claims shall be considered on their own merits in light of this disclosure, but should not be constrained by the headings set forth herein.