Abstract:
A solar panel mounting system having a support, a railing and a clamp by utilizing all the components made with the metal structural members available in the market without resorting to a special fabrication or extrusion for saving material costs. It also saves labor for installation. The plurality of supports are screw connected to the roof rafters to accommodate the solar panels. The plurality of rails are placed on the supports and screw connected at job site. The plurality of clamps are slid inside the rail tube from the ends of rails to proper locations for tightening the solar panels by plurality of clips.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    This invention relates to a mounting system with low cost and easy installation of solar panels on the roof of a building. 
       DESCRIPTION OF THE RELEVANT ART 
       [0002]    A great effort has been taking place in research and development of solar energy systems to generate electricity at a higher efficiency and a lower cost in recent years. The progress has been impressive. There are varieties of mounting systems in the market today. Most of them are made of special fabricated or extruded metals which are relatively expensive and time consuming to install. They resulted in a high percentage of the entire system costs. Technical labor to install the system on the roof under hot sun is difficult to find and expensive. This invention is to utilize the existing metal structural members in construction industry to reduce the material cost and to simplify the installation to save labor cost. 
       SUMMARY OF THE INVENTION 
       [0003]    A general object of this invention is to utilize the existing metal structural components with simple supporting and clamping devices to save the cost of materials. Another object of this invention is to simplify the installation of the system to save the labor costs. According to the present invention a supporting device is prefabricated with pre-drilled screw holes on the base plate for screws with waterproof gasket to fasten the support to the roof rafter. Liquid washer is used at the screw locations to further insure the water-proofing. A circular metal tube as support is weld connected to a base plate at the middle at the bottom, also weld connected to a rail holder with pre-drilled holes on the top. The rail is screw connected to the rail holder through the pre-drilled holes on the rail holder. A threaded rod placed inside the rail extended from the bottom of the rail to above the solar panels is weld attached with a square holding plate right below the top side of rail and another square plate as clip above the solar panels to clamp down the solar panels by a nut on the top. The solar panels are thus well connected to the roof structures. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0004]    The accompanying drawings, which are incorporated in and constitute a part of the specifications, illustrate preferred embodiments of the invention, and together with the description serve to explain the principles of the invention. 
           [0005]      FIG. 1  shows a partial plan of the solar panel system and mounting locations. 
           [0006]      FIG. 2  is an enlarged plan of the mounting system. 
           [0007]      FIG. 3  is a cross-section A-A of the mounting system , showing how the support is tied to the roof rafter. 
           [0008]      FIG. 4  illustrates the support with the structural components welded together and the locations of pre-drilled screw holes. 
           [0009]      FIG. 5  shows the rail with a pre-cut slot on the top of a rectangular tube. 
           [0010]      FIG. 6  shows the threaded rod weld connected by a square holding plate at the height right underneath the top side of the rail and another square plate above the solar panels as a clip to clamp down the solar panels by a nut. 
           [0011]      FIG. 6C  illustrates the way to cut a rectangular tube to two identical end panel clips. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0012]    Reference is now made in detail to the present preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals indicate like elements throughout the several views. 
         [0013]    With the rapid increase in the use of solar panels on the roof of buildings to generate electricity in recent years, various mounting systems have been created to install the solar panels. The cost of materials is relatively expensive because they are made of specially fabricated or extruded metals. This invention creates new simplified method by the utilization or modification of the existing structural members widely used in today&#39;s construction industry. The installation of the system is also simplified to save the labor costs. The support as illustrated in  FIG. 4  is made in the factory by weld connecting a circular tube  32  to a base plate  31  at the bottom and weld connecting a u-shaped rail holder  33  on the top. The base plate  31  can be cut from a regular aluminum sheet to a size of 1/4 inch thick by 1 1/2 inches width by 6 inches long for example. Two pre-drilled holes  35  located as shown on  FIG. 4  are provided for screws  36  with water-proof gasket to fasten support  3  to the roof rafter  1 . In addition to the gaskets on the screws, liquid washer  39  as shown on  FIG. 3A  is placed at the screw  36  locations before drilling screw  36  to the rafter  1  to double ensure the waterproofing. Only one row of screw holes  35  is provided herein because most rafter widths are around two inches or less which normally are not wide enough to accommodate more than one row of screws  36 . The number of screws  36  is determined by the loads, spacing of support  3  and the size of screw  36 . One row of two screws for four feet spacing of support  3  for example is sufficient for general applications. More than two screws in one row with a longer and thicker base plate  31  may be used if needed. Rafter  1  could be flat or sloped and its material could be wood, steel or concrete. A regular stainless steel lag screw for wood, self-drilling stainless steel screw for steel and stainless steel concrete screw for concrete are examples to fasten support  3  to roof rafter  1 . 
         [0014]    The circular tube  32  can be cut from a regular metal pipe, such as an 1 inch diameter by 1/8 inch wall thickness aluminum pipe for example. Its height depends on the needs for roof drain and ventilation underneath the solar panels  6 . Normally 2 inches to 6 inches is sufficient for applications. The top of the circular tube  32  can be cut flat as shown on  FIG. 3A  or tilted as shown on  FIG. 3B  according to the need of solar panels to be tilted toward the sun. The rail holder  33  can be cut from a regular rectangular metal tube with its width fit to hold rail  4 . It can be cut in half to two identical pieces from a 2 1/4 inch by 3 inch by 1/8 inch wall thickness of a regular aluminum rectangular tube at 1 1/2 inches leg height to fit a 2 inch by 2 inch square tube rail  4  for example. Pre-drilled holes  37  on both legs of the rail holder  33  are provided in factory to accommodate screw  38  for fastening support  3  to rail  4 . The use of self-drilling screw  38  at job site allows an even height of rail  4  on an inevitable small unevenness of the roof surface supported by plurality of identical supports  3  for the entire solar panel system. Screw  38  and its attaching structural members  33  and  41  should have enough strengths to carry downward and upward loads from the solar panels. Screw  38  should not be too long to interfere with the free passage of the threaded rod  51 . A 1/4 inch diameter by 3/4 inch long stainless steel self-drilling screw  38  for example can be used for a  2  inches by  2  inches rail  4 . 
         [0015]    Rail  4  as shown on  FIG. 5  is the main structural member made from a rectangular tube cut a slot  42  on the top to allow the plurality of threaded rods  51  to slide to proper locations from the ends of rail  4  for fastening the plurality of solar panels  6  to rail  4 . Its size is determined by the downward and upward loads from the plurality of solar panels  6  and spacing of the plurality of supports  3 . A  2  inches by 2 inches by 1/8 inch wall thickness aluminum square tube with 4 feet spacing of supports  3  for example is sufficient for normal applications. The 4 feet spacing of supports  3  can fit to most of the rafter spacing of 12 inch, 16 inches or 24 inches. 
         [0016]    Threaded rod  51  as shown on  FIG. 7  extends from the upper surface of the bottom side of rail  4  to above the solar panels  6  with sufficient length for nut  55  to fasten solar panels  6  to rail  4 . A partially threaded rod  51  sits on the upper surface of the bottom side of rail  4  so that screw rod  51  can stay at a proper height for fastening. A square holding plate  52  with its size fits to the distance between the interior faces of the side walls of rail  4  is weld attached to threaded rod  51 . Its rectangular shape prevents the threaded rode  51  from spinning when tightening nut  55  from the top. It also holds the solar panels  6  and rail  4  by clip  53  or  54 . A square clip plate  53  is used for a strong resistant to a high uplift wind load. It is placed on the top of solar panels  6  to fasten plurality of interior solar panels  6  to rail  4  as shown on  FIG. 6A . A clip  54  with the shape as shown on  FIG. 6B  is used for fastening end solar panels. Exterior clip  54  can be cut in two identical pieces as shown on  FIG. 6C . A 1 inch by 2 inches by 1/8 inch wall thickness aluminum rectangular tube can be cut to two identical exterior panel clips  54  at 2 inches long for example. A 1/4 inch diameter stainless steel rod  51  and a stainless steel nut  55  with 1/8 inch thick aluminum holding plate  52  and interior panel clip  53  for example can be used for general applications. This invention allows the space between the solar panels at screwed rod diameter of 1/4 inch as shown by the above example instead of 1 inch by using the mounting system as shown in U.S. Pat. No. 7,600,349, “Low Profile Mounting system” issued to John E. Liebendorfer on Oct. 13, 2009 for example. This less in space not only save the whole area covered by the system, it also create a better structural connection for the clip to tie down the solar panels. 
         [0017]    The present invention includes a method of installing the mounting system. The plurality of shop prefabricated supports  4  are screw connected to the plurality of roof rafters  1 . The plurality of supports  3  are placed at staggered locations for each row of solar panels  6  as shown on  FIG. 1  so that loads from the solar panels  6  can be properly distributed to all rafters  1  underneath all solar panels  6 . Rail  4  is placed on the plurality of support holders  3  before drilling screws  36  to the plurality of rafters  1  to ensure a proper alignment of supports  3 . Liquid washer  39  is placed in pre-drilled holes  35  prior to support  3  is fastened to rafter  1  by screw  36 . After examining the evenness of rail  4 , rail holder  31  is fastened to rail  4  by screw  38  through the pred-drilled hole  37  at the job site. Factory prefabricated plurality of threaded rods  51  welded to a square holding plate  52  are slid to the proper locations from the ends of rails  4 . The plurality of solar panels  6  are properly placed and fastened to rails  4  by nuts  55  with clips  53  underneath as shown on  FIG. 6A  for interior solar panels or  FIG. 6B  for end solar panels. 
         [0018]    It will be apparent to those skilled in the art that various modifications can be made to the mounting system of the instant invention without departing from the scope of spirit of the invention, and it is intended that the present invention covers modifications and variations of the mounting system provided they come within the scope of the appended claims and their equivalents.