Abstract:
The present invention is a clip and related grounding device. The grounding device has a wire connected to two clips at either end. Each clip is configured to be attached to the frame of a solar panel. The device eliminates fasteners that require bolts or screw to make a sufficient electrical connection between the panel frames. Because the grounding connects frame to frame, it is not necessary to ensure that the frames have a grounding connection to the underlying solar panel mounting system. This enables use of mounting systems that do not conduct electricity. The grounding device is has sufficient gripping strength that the anchoring teeth penetrate through paint, oxidized coating, or annealed finish to create an electrical connection.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a non-provisional that claims benefit of U.S. Patent Application Ser. No. 61/760,624 that is filed on Feb. 4, 2013. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates generally to a grounding system and clips for solar panels. 
         [0004]    2. Description of Background Art 
         [0005]    Solar panels have metal frames that require grounding for safety to prevent someone from touching the frame in a short-circuited system and getting a shock or electrocuted. Because a system for producing solar electric power has large numbers of panels affixed to a complex system of metal rails, the system can be grounded by ensuring that each panel has a sufficient electrical connection between the metal panel frames and the metal rail supports. If the rail system is likewise electrically connected, a single ground wire between the rail and a ground location can complete the grounding. 
         [0006]    Some of the most significant innovations in the solar industry are directed to lowering the overall price per kilowatt that a solar installation costs. As costs at any point in the supply chain for solar electric systems can be reduced, the overall viability of the solar system improves making it an economically favorable alternative to traditional energy sources such as coal or natural gas powered electrical plants. The time required to install a grounding system is a significant portion of the overall labor cost. Thus, some attention has been directed towards providing time saving, economical and effective grounding systems for various solar installations. 
         [0007]    U.S. Pat. No. 8,092,129 discloses a bonding washer for making electrical connections between two metal pieces that are to be mechanically fastened together. The washer is placed between the two metal pieces and the metal pieces are tightened together by a bolt or screw. Teeth on the washer are sandwiched between the two metal pieces and gouge through the two layers being affixed. The bonding washer creates an electrical connection between a panel and the underlying support structure such as rails. The bonding washer requires a fastener such as a bolt or screw fastener, which takes considerable more time. Thus there is a need for a system that may be faster than a grounding system that requires a screw or a bolt. 
         [0008]    U.S. Pat. No. 8,303,357 to Kuwahara discloses a grounding connection mechanism. The system has a U-shaped cam block that cooperates with a shaft to create downward pressure on a conductor/connecting washer to create a connection. Likewise, this system requires a screw or bolt. 
         [0009]    U.S. Pat. No. 8,475,185 to discloses a grounding clip having teeth for electrically bonding two panels and to a second channel section of a top member that functions to support the panels at a predetermined angle. The system requires at least a portion of the second channel section of a top member to be metal to complete the connection. The system requires a screw or bolt to make the connection. However, if a screw or bolt fastener is required to attach the panels to the underlying rail or support, then the grounding system does not need an additional bolt. Nonetheless, if this grounding system would not be useful with a rapid fastening system that does not require a screw or bolt to fasten the panel to underlying rails. 
         [0010]    U.S. Patent Publication No. 20110151703 discloses a swiveled electrical connector for connecting a wire to the frame of a solar panel. The system functions to connect at least one panel to a ground wire in a manner that allows the portion of the connector that clamps the wire to swivel relative to the portion of the connector that connects the panel. The device can be used to electrically connect two panels together with a common ground wire. 
         [0011]    U.S. Pat. No. 5,451,167 discloses a grounding clip. In one embodiment, the grounding clip connects to an appliance panel and has a pair of vertical passageways into which a wire can be inserted to create a positive electrical connection for the purpose of grounding the wire to the appliance panel. It is questionable whether this grounding could be used in an all weather application. It is also questionable whether this grounding clip would be sufficiently robust for a long-term period of use consistent with solar panels. 
         [0012]    U.S. Pat. No. 4,993,959 discloses a grounding clip comprising a U-shaped panel contact comprising inwardly directed tines. There is a wire contact section that has a crimp section. The crimp section is formed towards the side of the U-shaped panel contact. The crimping section is designed for an eighteen (18) gauge wire. The point where the crimping section connects to the remainder of the grounding device is weak and prone to breakage. 
         [0013]    Nonetheless, there still exists a need for a grounding system that can extend a ground wire from one solar panel to another that can be applied rapidly without screws or bolts to slow the attachment process and imparts sufficient clamping strength to create a contact through a paint layer and annealing. There is a need for devices that are strong and durable capable of use in all weather conditions. One or more embodiments of the present invention addresses these and other needs. 
       SUMMARY OF THE INVENTION 
       [0014]    The present invention is a clip and related grounding device. The grounding device has a wire connected to two clips at either end. Each clip is configured to be attached to the frame of a solar panel. The device eliminates fasteners that require bolts or screw to make a sufficient electrical connection between the panel frames. Because the grounding connects frame to frame, it is not necessary to ensure that the frames have a grounding connection to the underlying solar panel mounting system. This enables use of mounting systems that do not conduct electricity to support metal frame panels that require a grounding system. The grounding device has sufficient gripping strength so that the anchoring teeth penetrate through paint, oxidized coating, or annealed finish to create an electrical connection. 
         [0015]    A solar panel grounding clip for securing a grounding wire to a solar panel frame. The grounding clip comprises a strip of spring steel of a predetermined width that is formed and cut to define a generally U-shaped receptacle having a top clamping jaw and a bottom clamping jaw configured to receive a panel. 
         [0016]    The receptacle has a back wall and a forward positioned mouth. The receptacle height adjacent the back wall conforms to the thickness of the solar panel frame and narrows towards the forward positioned mouth. Each of the top clamping jaw and bottom clamping jaw have one or more rearwardly and inwardly directed teeth, respectively. The mouth further defines two outwardly diverging lips defining a panel receiving opening forward the mouth. One lip is formed into a wire-crimping loop that is configured to receive and clip a grounding wire at one end of the grounding wire. 
         [0017]    In one embodiment, the grounding clip is made of stainless spring steel. The stainless spring steel has a minimum thickness of 0.5 mm and a maximum of 0.7 mm. 
         [0018]    In another embodiment, the receptacle has a width that is a minimum of 1.0 mm and a maximum of 3.5 mm wire creates a sufficient bond. 
         [0019]    In one aspect of the invention, there is a solar panel grounding device for securing a grounding wire between a first solar panel frame and a second solar panel frame. The solar panel grounding device has a wire with a first end and a second end. 
         [0020]    A first clip formed from a first strip of spring steel of a predetermined width that is formed and cut to define a generally U-shaped first receptacle configured to receive a first panel. The first clip has a first top clamping jaw and a first bottom clamping jaw. The first receptacle has a first back wall and a forward positioned first mouth. The receptacle height adjacent the back wall conforms to the thickness of the solar panel frame and narrows towards the first mouth. Each of the first top clamping jaw and first bottom clamping jaw have one or more rearwardly and inwardly directed teeth adjacent the first mouth, respectively. The first mouth further defines two outwardly diverging first lips defining a panel receiving first opening forward the first mouth. One first lip is formed into a wire 12-crimping loop and crimp holds the first end of the wire. 
         [0021]    The solar panel grounding device has a second clip formed from a second strip of spring steel of a predetermined width that is formed and cut to define a generally U-shaped first receptacle configured to receive a second panel. The second clip has a second top clamping jaw and a second bottom clamping jaw. The second receptacle has a second back wall and a forward positioned second mouth. The receptacle height adjacent the back wall conforms to the thickness of the solar panel frame and narrows towards the second mouth. Each of the second top clamping jaw and second bottom clamping jaw have one or more rearwardly and inwardly directed teeth adjacent the second mouth, respectively. The second mouth further defines two outwardly diverging second lips defining a panel receiving second opening forward the second mouth. One second lip is formed into a wire crimping loop that is configured to receive and fasten by compressing or crimping the wire crimping loop around the grounding wire at one end of the grounding wire. 
         [0022]    In one embodiment, the first clamp and second clamp are made of stainless spring steel. Preferably, the stainless spring steel has a minimum thickness of 0.5 mm and a maximum of 0.7 mm. 
         [0023]    The grounding wire is a tin or nickel-plated copper wire. Preferably the wire is tin plated copper wire. Typically, the grounding wire is bare in that it does not have an insulated sheath over the wire. 
         [0024]    In one embodiment, the wire is fourteen gauge or larger, preferably twelve gauge or larger. 
         [0025]    The wire has a thickness that is a minimum of 0.015 inches. 
         [0026]    In one embodiment, the receptacle has a width that is a minimum of 1.0 mm and a maximum of 3.5 mm wire creates a sufficient bond. 
         [0027]    In another embodiment, there is a method of electrically connecting two solar panel frames comprising the steps of providing one or more of the grounding devices disclosed above. The method comprises the steps of attaching the first clip to the first frame and attaching the second clip to the second frame. 
         [0028]    The frame and second frame are selected to have a thickness that is a minimum of 1.0 mm and a maximum of 3.5 mm. 
         [0029]    The step of attaching the first clip and the step of attaching the second clip causes the teeth to remove a layer of annealing and/or paint. 
         [0030]    In one embodiment of the method of the present invention, the first frame and the second frame are mounted to a mounting system or support device that is not an electrical conductor. 
         [0031]    The present invention, including its one or more embodiments, can be better understood with reference to the following drawings, detailed description and examples, which are included to teach the invention without limiting the scope of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0032]      FIG. 1  is a perspective view of a grounding clip of one embodiment of the invention. 
           [0033]      FIG. 2  is a bottom view of  FIG. 1 . 
           [0034]      FIG. 3  is an elevated side view taken along the lines  3 - 3  of  FIG. 2 . 
           [0035]      FIG. 4  is a top view taken along lines  4 - 4  of  FIG. 3 . 
           [0036]      FIG. 5  is a plan view of the grounding clip of one embodiment showing the cuts and folds prior to stamping. 
           [0037]      FIG. 6  is a perspective view of the grounding device of one embodiment of the present invention. 
           [0038]      FIG. 7  is an elevated side view of the grounding device of one embodiment of the present invention. 
           [0039]      FIG. 8  is an elevated side view of the grounding device in an expanded state receiving the solar panel frame into the grounding clip  10  receptacle  16 . 
       
    
    
     DETAILED DESCRIPTION 
       [0040]    With reference to  FIGS. 1-4 , a grounding clip of one embodiment of the present invention is shown. The solar panel grounding clip  10  is for securing a grounding wire  12  (see  FIG. 6 ) to a solar panel frame  8  (see  FIG. 9 ). The grounding clip  10  is designed to provide a powerful hold on a solar panel frame  8 , yet not require screws, bolts, clamps, crimping tools, pliers, lever or the like to increase the clamping force of the grounding clip  10 . The simple design eliminates excessive parts and complex assembly steps making the device easy to make. 
         [0041]    At best, a light tap of a hammer or mallet is the only assistance that a user may require to assist affixing the grounding clip  10  to the panel frame  8 . Thus, the grounding clip  10  design eliminates the need for tools with the exception of a possible mallet. The grounding clip  10  comprises a strip of spring steel of a predetermined width that is formed and cut to define a generally U-shaped receptacle  16  having a top clamping jaw  18  and a bottom clamping jaw  20  configured to receive a panel frame  8  into the receptacle  16  between the jaws  18  and  20 . 
         [0042]    With particular reference to  FIGS. 1 to 4 , the receptacle  16  has a back wall  22  and a forward positioned mouth  24 . A top lip  34  and a bottom lip  36  diverge in a forward direction from the mouth  24  to provide an opening  37  to receive the panel frame  8 . The receptacle  16  height A adjacent the back wall conforms to the thickness of the solar panel frame  8  and narrows B towards the forward positioned mouth  24 . The top clamping jaw  18  has two side-cut teeth  26 . The bottom clamping jaw  20  has one center cut tooth  28  and two side-cut teeth  30 . The teeth  26 ,  28 , and  30  point inwardly and rearwardly. 
         [0043]    A panel frame  8  is inserted into the receptacle  16  past the mouth  24  by a force in the direction of F 1  as shown in  FIG. 8 . The panel frame  8  slides into the sloped side of the teeth  26  on the top jaw  18  and the teeth  28  and  30  on the bottom jaw  20  with relative ease. Once the panel frame  8  is inserted past the tip of the forward most positioned top teeth  30 , the panel frame  8  can only move into the receptacle  16 . The force of the spring jaws  18  and  20  cooperate to cause the tips of the teeth  26 ,  28  and  30  to penetrate a layer of oxidized aluminum, annealing or even a painted layer on the panel frame  8  and grip the panel frame  8 . The teeth  26 ,  28  and  30  are forced past the superficial oxidized or protected layer into the soft aluminum of most frames making at least five points of electrical contact. 
         [0044]    But, when a force is applied in the direction of F 2  opposite F 1 , the points of the top teeth  26 , on the top jaw  18  and the points of the bottom teeth  28  and  30  on the bottom jaw  20  cooperate to dig the panel frame  8  and prevent movement of the panel frame  8  out of the mouth  24 , thereby securing the panel frame  8  in the jaws  18  and  20 . 
         [0045]    As noted, the mouth  24  further defines an outwardly diverging top lip  34  and an outwardly diverging bottom lip  36 . In the present embodiment of  FIGS. 1-4 , the bottom lip  36  is bent back into a wire-crimping loop  38  that is configured to receive and bind to a grounding wire  12  at one end of the grounding wire  12 . 
         [0046]    With reference to  FIG. 5 , the grounding clip  10  is made by cutting, pressing and forming an elongated strip of spring steel according to the pattern  41  of  FIG. 5 . 
         [0047]    In one embodiment, the grounding clip  10  is made of stainless spring steel. The stainless spring steel has a minimum thickness of 0.5 mm and a maximum of 0.7 mm. 
         [0048]    Top lip  34  is bent along top lip fold line  46 . The top jaw  18  generally extends from top lip fold line  46  to top back wall fold line  48 . The back wall  22  generally extends from top back wall fold line  48  to bottom back wall fold line  50 . The receptacle  16  adjacent the back wall  22  has a width that is a minimum of 1.0 mm and a maximum of 3.5 mm, preferably 3.1 mm. A 3.2 mm receptacle  16  is effective at clipping to a panel ranging from 1.1 mm to 3.06 mm. 
         [0049]    The bottom jaw extends from bottom back wall fold line  50  to approximately the mouth  24  that begins proximate bottom teeth  26  and  28 . A jogging double bend formed in region  44  will be formed to narrow the receptacle  16  from the portion of the receptacle  16  adjacent the back wall  22  towards the mouth  24 . Bottom teeth  26  and  28  when processed are cut to the shape of the teeth  26  and  28 . They are pressed upward from the bottom jaw  20  on an angle in a rearward direction. The bottom lip  36  is rolled to form the wire-crimping loop  38 . 
         [0050]    The system can be stamped in multiple steps or formed with a four-way press such as a four-slide press. The grounding wire  12  is connected to the grounding clips by compressing the wire crimping loop onto the wire in the four slide press at the factory while the grounding clips  10  are being pressed to ensure connection of consistent quality and save time at the installation site. Grounding wires  12  can be of a predetermined length. 
         [0051]    In one embodiment shown in  FIGS. 6-8 , two clips  10  of one or more embodiments described above are attached to each ends of a grounding wire  12  of predetermined length and thickness. 
         [0052]    The grounding wire  12  is a tin or nickel-plated copper wire. Preferably the grounding wire  12  is tin plated copper wire. Typically, the grounding wire  12  is bare in that it does not have an insulated sheath over the grounding wire  12 . 
         [0053]    In one embodiment, the grounding wire  12  is fourteen gauge or larger, preferably twelve gauge or larger. Depending upon the application, a 12 gauge wire having a 2.1 mm diameter is sufficient to ground most 12 panel arrays. 
         [0054]    In another embodiment, there is a method of electrically connecting two solar panel frames comprising the steps of providing one or more of the grounding devices disclosed above. A clip  10  is affixed to the underside of a panel frame  8  by placing the mouth  24  of the grounding clip  10  directly over the panel frame  8 . The user (preferably wearing work gloves) can grasp the panel frame  8  and the grounding clip  10  between the thumb and forefinger and press until the grounding clip  10  slides over the panel frame  8  until the panel frame  8  abuts against the back wall  16  of the grounding clip  10  or close to the back wall  16 . The grounding wire  12 , preferably unbent extends longitudinally along the frame  8  to an adjacent frame  8 . 
         [0055]    The step of attaching the first clip and the step of attaching the second clip causes the teeth to remove a layer of annealing and/or paint by creating a gouge or groove in the paint, annealed surface or oxidized layer. The removal of this covering layer is an important part of the invention because it improves the quality of the connection. 
         [0056]    In one embodiment of the method of the present invention, the first frame and the second frame are mounted to a mounting system or support device that is not an electrical conductor. 
       Example 1  
     Short-Time Current Test 
       [0057]    Method: Three samples of the grounding device were subjected to the above test. 
         [0058]    The grounding device was not intended for attachment to a rod, conduit, pipe, outlet box etc., and so was assembled in the intended manner using its largest rated conductor. Specifically, in each of the three samples a grounding wire  12  connected two solar panel frames. 
         [0059]    The grounding device was subjected to the test current for the specified time. The test current passed through the first panel, the first clip, the 12-gauge nickel-plated grounding, the second clip and the second solar panel frame in series. The current of 470 Amps was passed through for four seconds. 
         [0060]    After having carried the specified current, the test sample assembly was evaluated for continuity from the first panel through the grounding device to the second panel. An indicating device such as an ohmmeter, battery-and-buzzer combination, or the like, was used to determine whether electrical continuity existed after the system was subject to the current. 
         [0061]    Results: The results were acceptable since the grounding or bonding device did not crack, break, or melt and continuity was maintained on all sample assemblies.