Abstract:
We disclose a method for securing an infrared transmissive polymer to integrated panels, deadfronts, or transition plates, thus providing a reinforced polymer window through which the thermographer can scan an energized unit without being directly exposed to contact with internal components or having to remove said panels, deadfronts, or transition plates. We also disclose a device for securing the polymer consisting of a retention frame with half shear retainers that keep the polymer locked in place.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention is generally directed toward a method and device for affixing an infrared transmissive polymer window to a panel of an electrical enclosure. 
       BACKGROUND OF THE INVENTION 
       [0002]    Thermal infrared scans of switchgear and other electrical enclosures allow technicians to monitor and possibly identify faulty or failing components within the device. However, to get an accurate scan, the thermal imaging must be performed while the device is energized and, either with the enclosure panels removed to provide a clear view of the electrical components, or through a viewing window. 
         [0003]    These windows are typically made of an extremely thin infrared transmissive polymer. However, this thin polymer window must be reinforced with hard material to give it structural integrity so that it does not break or become damaged due to heat or pressure from within the panel. This material is typically perforated with an array of holes such that it forms a protective grill. However, the protective grill adds a layer that may obscure the imaging infrared scanner&#39;s view of the electrical components and could interfere with the accuracy of the imaging process. 
       SUMMARY OF THE INVENTION 
       [0004]    We disclose a method of securing an infrared transmissive polymer to integrated panels, deadfronts, or transition plates, thus providing a polymer window through which the thermographer can scan an energized unit without being directly exposed to harm. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0005]    Further advantages of the invention will become apparent by reference to the detailed description of preferred embodiments when considered in conjunction with the drawings: 
           [0006]      FIG. 1  depicts a perspective view of the infrared scanning port as viewed from inside the electrical panel. 
           [0007]      FIG. 2  depicts an elevation view of the infrared scanning port as viewed from inside the electrical panel. 
           [0008]      FIG. 3  depicts a left side elevation view of the infrared scanning port. 
           [0009]      FIG. 4  depicts an elevation view of the infrared scanning port as viewed from the front. 
           [0010]      FIG. 5  depicts a right side elevation view of the infrared port. 
           [0011]      FIG. 6  depicts an exploded perspective view of the infrared port. 
           [0012]      FIG. 7  depicts a left side elevation view of the inset A of  FIG. 3 . 
       
    
    
     DETAILED DESCRIPTION 
       [0013]    The following detailed description is presented to enable any person skilled in the art to make and use the invention. For purposes of explanation, specific details are set forth to provide a thorough understanding of the present invention. However, it will be apparent to one skilled in the art that these specific details are not required to practice the invention. Descriptions of specific applications are provided only as representative examples. Various modifications to the preferred embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be applied to other embodiments and applications without departing from the scope of the invention. The present invention is not intended to be limited to the embodiments shown, but is to be accorded the widest possible scope consistent with the principles and features disclosed herein. 
         [0014]    As will be appreciated from the figures, panel  2  is a unit enclosure panel that separates the electrical components within it from the environment, including integrated panels, deadfronts, or transition plates. Aperture  20  in panel  2  is an opening through which the infrared scanner has a line of sight view of the electrical components. Although the embodiment shown in the figures has an aperture  20  that is approximately hexagonal shape and about four inches wide between the vertices, aperture  20  may be any shape and size to allow an infrared camera to have an unobstructed view of the electrical components in the electrical panel. 
         [0015]    Panel  2  also has a series of retention holes  14  surrounding the aperture  20 . The retention holes  14  are configured to receive a portion of infrared transmissive polymer  4  and retention frame  6  as part of the half shear retention system that will keep the infrared transmissive polymer  4  in place. In a preferred embodiment, these retention holes  14  are located annually around aperture  20 . 
         [0016]    As will be appreciated from  FIG. 6 , the infrared transmissive polymer  4  will act as a window over the aperture  20 . The infrared transmissive polymer  4  is a thin flexible sheet of polymer that allows the passage of infrared radiation through it. When positioned over aperture  20 , the edges of the infrared transmissive polymer  4  extend beyond aperture  20  and overlap with panel  2 . 
         [0017]    A portion of infrared transmissive polymer  4  that overlaps with panel  2  is sandwiched between panel  2  and retention frame  6 . Retention frame  6  is generally a flat piece of hard material, such as metal, having an opening in the interior that approximates the shape and size of aperture  20  and is referred to herein as frame opening  22 . As can be seen from the  FIG. 1 , in one embodiment, the frame opening  22  is a symmetric, approximately hexagonal shape with cutouts to accommodate a captive retention bolt  18  (described below). 
         [0018]    As can be seen from  FIG. 7 , retention frame  6  includes a series of half shear retainers  8  that surround frame opening  22 . These half shear retainers  8  are dimple-like protrusions that extend from the plane of the retention frame  6 . In a preferred embodiment, the half shear retainers  8  protrude beyond the plane to a distance of approximately half of the width of the retention frame  6 . The half shear retainers  8  are positioned around the frame opening  22  such that each one lines up with a retention hole  14  in the panel  2  when they are placed against each other. The infrared transmissive polymer  4  also may include a series of holes, referred to as polymer holes  24 , that are positioned in a corresponding pattern to the retention holes  14  in the retention frame  6 . Each half shear retainer  8  is configured to pass through a corresponding polymer hole  24  and into a retention hole  14  in the panel  2  when the retention frame  6  and infrared transmissive polymer  4  are properly oriented and positioned together. 
         [0019]    When properly oriented such that the half shear retainers  8  in the retention frame  6  each  14  line up with a corresponding polymer hole  24  and retention hole  14  in the panel  2 , the retention frame  6  and infrared transmissive polymer  4  can be positioned against panel  2 , effectively sandwiching the infrared transmissive polymer  4  between retention frame  6  and panel  2 . The assembly can then be secured by the use of hardware such as the retaining nuts  10  and retaining bolt  26 . Retaining bolt  26  can be passed through holes in panel  2 , infrared transmissive polymer  4 , and retention frame  6 . Retaining nut  10  can then be fastened onto the bolt, such that the retention frame  6  is secured against panel  2 . It should be appreciated that retaining bolt  26  is short enough that it does not protrude very far into the electrical panel. This helps ensure that it does not come into contact with any energized electrical components. 
         [0020]    With retention frame  6  securely fastened against panel  2 , infrared transmissive polymer  4  is secured and is prevented from moving due to the series of half shear retainers  8  positioned around frame opening  22 . The infrared transmissive polymer  4  would act as a window that infrared radiation can pass through while preventing contaminants from entering the electrical enclosure. The infrared transmissive polymer  4  would also prevent a user from inadvertently contacting electrical components housed within the electrical enclosure. 
         [0021]    In a preferred embodiment, a cover  12  is provided that protects the transmissive infrared polymer  4  from being exposed to the environment, thus reducing the risk of it become damaged or dirty. As can be seen in  FIG. 4 , cover  12  is approximately the same shape and slightly larger than aperture  20 , such that it completely obscures aperture  20  when it is in a closed position. Cover  12  can swing in front of the aperture  20  due to it being affixed to the panel  2  through pivot point  16 . The cover  12  is configured such that it can hook against captive retention bolt  18  and remain in a closed position. 
         [0022]    The terms “comprising,” “including,” and “having,” as used in the claims and specification herein, shall be considered as indicating an open group that may include other elements not specified. The terms “a,” “an,” and the singular forms of words shall be taken to include the plural form of the same words, such that the terms mean that one or more of something is provided. The term “one” or “single” may be used to indicate that one and only one of something is intended. Similarly, other specific integer values, such as “two,” may be used when a specific number of things is intended. The terms “preferably,” “preferred,” “prefer,” “optionally,” “may,” and similar terms are used to indicate that an item, condition or step being referred to is an optional (not required) feature of the invention. 
         [0023]    The invention has been described with reference to various specific and preferred embodiments and techniques. However, it should be understood that many variations and modifications may be made while remaining within the spirit and scope of the invention. It will be apparent to one of ordinary skill in the art that methods, devices, device elements, materials, procedures and techniques other than those specifically described herein can be applied to the practice of the invention as broadly disclosed herein without resort to undue experimentation. All art-known functional equivalents of methods, devices, device elements, materials, procedures and techniques described herein are intended to be encompassed by this invention. Whenever a range is disclosed, all subranges and individual values are intended to be encompassed. This invention is not to be limited by the embodiments disclosed, including any shown in the drawings or exemplified in the specification, which are given by way of example and not of limitation. 
         [0024]    While the invention has been described with respect to a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments can be devised which do not depart from the scope of the invention as disclosed herein. Accordingly, the scope of the invention should be limited only by the attached claims.