Patent Publication Number: US-2016240964-A1

Title: Grounding assembly for sunken placement

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of priority of U.S. provisional patent application No. 62/117,904, titled “Sunken Grounding Apparatus,” filed on Feb. 18, 2015, which is incorporated herein in its entirety by this reference. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to electrical-grounding equipment. More particularly, the present disclosure relates to an apparatus for storing grounding cable and clamp assemblies in sunken placement. 
     BACKGROUND 
     The electrical grounding of an aircraft while fueled and serviced on land, for example at an airport, is typically accomplished using long cables that in some instances must be extended inconveniently across runway or hangar surfaces. A poorly grounded aircraft represents a significant potential sparking hazard particularly when fueling or defueling. Not only can uncontrolled electrical discharges cause fires, they can cause damage to sensitive electronics equipment as well both to on-board systems and ground-based maintenance and diagnostic equipment. 
     The grounding cables typically used are appropriately constructed with heavy-gauge wire and so they are cumbersome to extend and move in busy environments where ground vehicles are moving to load, unload and service aircraft recently landed or preparing for flight. It is preferred that such cables not be driven over by vehicles; and the clamps on the ends of the cables are particularly subject to damage or contamination if poorly treated. 
     Improvements are needed in grounding cable equipment and methods. 
     SUMMARY 
     This summary is provided to introduce in a simplified form concepts that are further described in the following detailed descriptions. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it to be construed as limiting the scope of the claimed subject matter. 
     In at least one embodiment, a grounding assembly for sunken placement in a surface includes: a housing for sunken placement in a surface, the housing defining an interior space; a top plate covering the interior space of the housing, the top plate defining an opening; an access panel having a closed configuration, in which the access panel covers the opening of the top plate to prevent access to the interior space of the housing, and at least one open configuration in which the access panel does not cover the opening of the top plate to permit access to the interior space of the housing; and at least one grounded cable at least partially within the interior space of the housing and configured to be deployed through the opening of the top plate. 
     In at least one example, a strut spans the opening of the top plate and supports the access panel when the access panel is in the closed configuration. 
     In at least one example, the housing includes a bottom floor and four planar vertical side-wall sections. 
     In at least one example, a strut has longitudinal ends connected to respective side-wall sections. 
     In at least one example, the access panel is connected to the top plate by a hinge permitting pivoting of the access panel from the closed configuration to the open configuration. 
     In at least one example, a reel assembly is included within the interior space of the housing and upon which the grounded cable can be rolled for storage. 
     In at least one example, a cutout is formed in an edge of the access panel to accommodate the grounded cable when the grounded cable is deployed and the access panel is in the closed configuration. 
     In at least one example, holes are formed in the top plate to accommodate fasteners by which to fix the grounding assembly to a surface. 
     In at least one example, the top plate has a traction pattern. 
     In at least one example, the top plate has holes to receive fasteners for fixing the grounding assembly to a surface. 
     In at least one example, the housing comprises an outward extending flange contacting the top plate. 
     In at least one example, the top plate has first holes to receive fasteners for fixing the grounding assembly to a surface; and the flange has second holes respectively aligned with the first holes. 
     In at least one example, a grounding rod is electrically connected to the at least one grounded cable. 
     In at least one example, a grounding rod is electrically connected to the at least one grounded cable. 
     In at least one example, the at least one grounded cable is electrically connected to the housing, and a grounding rod is electrically connected to the housing such that the at least one grounded cable is electrically connected to the grounding rod by way of the housing. 
     In at least one example, an electrical contact is connected to a free end of the at least one grounded cable. 
     In at least one example, the electrical contact comprises a clamp. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The previous summary and the following detailed descriptions are to be read in view of the drawings, which illustrate particular exemplary embodiments and features as briefly described below. The summary and detailed descriptions, however, are not limited to only those embodiments and features explicitly illustrated. 
         FIG. 1  is upper perspective view of a grounding assembly for sunken placement in a ground or floor surface according to at least one embodiment. 
         FIG. 2  is a lower perspective view of the grounding assembly of  FIG. 1 . 
         FIG. 3  is a plan view of the top plate of the grounding assembly of  FIG. 1  shown with a top-side access panel closed. 
         FIG. 4  is an example of a traction pattern for the upper surface of the top plate of  FIG. 3 . 
         FIG. 5  is a plan view of the top plate of the grounding assembly of  FIG. 1  shown with the top-side access panel opened and cables deployed. 
         FIG. 6  is an elevation view of the grounding assembly of  FIG. 1  installed below or flush with a floor or ground surface and showing a view of a reel from which a cable is deployed through the open top-side access panel. 
         FIG. 7  is a lower perspective view of a grounding assembly, according to at least one embodiment, in which exemplary arrangements for grounding and securing the grounding assembly are illustrated. 
         FIG. 8  is a plan view of the top side of the lower housing of the grounding assembly, according to at least one embodiment. 
     
    
    
     DETAILED DESCRIPTIONS 
     These descriptions are presented with sufficient details to provide an understanding of one or more particular embodiments of broader inventive subject matters. These descriptions expound upon and exemplify particular features of those particular embodiments without limiting the inventive subject matters to the explicitly described embodiments and features. Considerations in view of these descriptions will likely give rise to additional and similar embodiments and features without departing from the scope of the inventive subject matters. Although the term “step” may be expressly used or implied relating to features of processes or methods, no implication is made of any particular order or sequence among such expressed or implied steps unless an order or sequence is explicitly stated. 
     Any dimensions expressed or implied in the drawings and these descriptions are provided for exemplary purposes. Thus, not all embodiments within the scope of the drawings and these descriptions are made according to such exemplary dimensions. The drawings are not made necessarily to scale. Thus, not all embodiments within the scope of the drawings and these descriptions are made according to the apparent scale of the drawings with regard to relative dimensions in the drawings. However, for each drawing, at least one embodiment is made according to the apparent relative scale of the drawing. 
     A grounding assembly  100  for sunken placement in a ground or floor surface  50  ( FIG. 6 ) such as that of a hangar, maintenance shop or tarmac is shown in  FIGS. 1-6 . The grounding assembly  100  has a lower housing  101  shown in a rectangular box-like configuration having a planar bottom floor  102  ( FIG. 2 ) and four planar vertical side-wall sections  104 . The side-wall sections  104  together define a continuous wall around an interior enclosure space  106  ( FIGS. 5-6 ). A wall surrounding an interior enclosure space in other embodiments of a grounding assembly according to these descriptions can have more or less side-wall sections. For example, in at least one embodiment such a wall is circularly cylindrical. Other configurations and shapes of the housing  101  are within the scope of these descriptions. 
     The grounding assembly  100  has a top plate  108  generally covering the interior enclosure space. The top plate  108  is connected to the upper edges of the side-wall sections  104 , for example by welding or other attachment. A top-side access panel  110  having open ( FIGS. 5-6 ) and closed ( FIGS. 1 and 3 ) configurations permits access, in an open configuration, to the interior enclosure space  106  of the grounding assembly  100 . As shown in  FIG. 5 , the top-side access panel  110  in an open configuration permits access to the interior enclosure space  106  though an opening  112  defined by the top plate  108 . As shown in  FIGS. 1 and 3 , the top-side access panel  110  in its closed configuration covers or fills the opening  112 , preventing access to the interior enclosure space. The access panel  110  is connected in the illustrated embodiment along a marginal edge to the top plate  108  by a hinge  114  ( FIG. 5 ) permitting the access panel  110  to be pivoted around the hinge  114  to open configurations from the closed configuration. 
     The access panel  110  in at least one embodiment is flush upon closure with the upper surface of the top plate  108  defining floor or ground space where vehicle movements and other operations can occur unobstructed. The top plate  108  and access panel  110  are illustrated as generally planar, expectedly for installation and use with the top plate  108  in a horizontal disposition parallel to and optionally flush with a ground or floor surface  50  ( FIG. 6 ). 
     A strut  116  ( FIG. 5 ) spans the opening  112  below the top plate  108 , for example to strengthen the grounding assembly  100  and to support the access panel  110  and prevent extension thereof below the closed configuration. For example, in at least one embodiment, the strut  116  is connected at its longitudinal ends to opposite side-wall sections  104  and spans the upper end of the interior enclosure space  106  ( FIG. 8 ). The strut  116  supports the top plate  108  (when closed) and any other load such as a vehicle wheel that may travel over or park on the top plate  108  and access panel  110 . 
     A lip  120  of the top plate  108  extends horizontally defining an upper ground perimeter of the grounding assembly  100 , encircling the access panel  110  when hinged down to its closed horizontal position. The top plate  108  can lie upon, flush with, or even slightly below ( FIG. 3 ) the ground surface  50  in various installation preferences. In the sunken placement of the grounding assembly  100  of  FIG. 6 , the top plate  108  is shown as flush or almost flush with the surrounding ground or floor surface  50 . 
       FIG. 4  is an example of a traction pattern  122  for the upper surface of the top plate  108  and that of the access panel  110  as well. While other examples are within the scope of these descriptions, the traction pattern  122  for example can be formed, stamped, etched, applied, or otherwise effected in any desired area  124  ( FIGS. 3,4 ) of the upper surface of the top plate  108  and across the entire top plate  108  and access panel  110  as desired. The traction pattern  122 , and optionally other traction patterns, provides for a repeating non-uniform upper surface of the top plate  108  to increase traction. 
     Various implements, tools, structures and arrangements are available within the interior enclosure space  106  of the grounding assembly  100  in various embodiments. Advantageous features and implements are particularly illustrated in  FIGS. 5 and 6 . For example, the expressly illustrated embodiment of the grounding assembly  100  includes grounding cables  130  deployed from reel assemblies  132 . When not in use, each grounding cable  130  can be stored upon a respective reel assembly  132 , each of which includes a spool upon which a grounding cable  130  is rolled for storage within the interior enclosure space  106  of the grounding assembly  100 . The top-side access panel  110  can be closed to protect the stowed cables and assemblies, to prevent tripping, and to prevent tools, debris and vehicle wheels from dropping into the interior enclosure space  106 . 
       FIG. 5  is a plan view of the top plate  108  of the grounding assembly of  FIG. 1  shown with the top-side access panel  110  opened and grounding cables  130  deployed to arbitrary lengths representing any desired length of deployment. For deployment and use, the top-side access panel  110  can be opened and each grounding cable  130  can be unrolled from its reel assembly  132  to a desired free length. Each illustrated grounding cable  130  is shown as having an electrical contact  134  at its free end for electrical contact with an aircraft or other structure to be grounded. Thus, the electrical contacts  134  are deployed with the grounding cables  130 . As shown in  FIG. 3 , cutouts  140  are formed in an edge of the access panel  110  to accommodate the grounding cables  130  extending from the grounding assembly  100  even when the access panel is closed. 
     Each reel assemblies  132  may have spring-return or bias to rewind its cable  130  or may be hand operated for rewinding. In the illustrated embodiment, a respective stop piece  136  is mounted on each grounding cable  130  to halt rewinding as the electrical contact  134  approaches reel assembly  132 . 
     The cables  130  and electrical contacts  134  are electrically conductive, and may have protective insulating sheaths or covers. For example, the grounding cables  130  may have conducting multi-strand metal wire cores sheathed in electrically insulating outer layers of polymer, rubber or other insulating material. The electrical contacts  134  are electrically conductive, and each is in electrical communication with its grounding cable  130 . For example, each electrical contact  134  may be a spring-biased clamp having forward electrically conducting jaws. Each electrical contact  134  may have a plug or other terminal arrangement for electrical connection to a corresponding mating plug or other terminal arrangement mounted on or electrically connected to a vehicle such as an aircraft. 
     A grounding rod  150  electrically common to the grounding cables  130  is shown in  FIGS. 2 and 7  as extending through a central portion of the floor  102  of the grounding assembly  100  to assure electrical grounding to earth. Other placements can be made in various embodiments. The grounding rod  150  assures proper grounding of the grounding cables  130  and electrical contacts  134 . The top plate  108 , the floor  102  and the side-wall sections  104  may be constructed, for example, of steel, aluminum or other electrically conducting metals. The top plate  108 , the floor  102  and the side-wall sections  104  may also be electrically common to the grounding rod  150  as well. 
     In  FIG. 6 , the grounding cable  130  is shown as electrically connected to the housing  101 , for example by connection  138  to a side-wall section  104 . The connection  138  represents an extension of the cable  130 , a second cable connected to the cable  130 , or any electrical connection between the grounding cable  130  and the housing  101 . In that example, the housing  101  is electrically connected to the grounding rod  150 . Thus, the grounding cable  130  can be electrically connected to the grounding rod  150  directly or indirectly. In at least one embodiment, the grounding cable  130  is electrically connected to the housing  101 , which is grounded to earth by contact without a grounding rod being necessitated. In various embodiments, the housing  101  or at least a part of the housing  101  is electrically conductive. 
     Holes  160  are shown as formed through the top plate  108  to receive fasteners  162  ( FIG. 1 ) and fix the grounding assembly  100  in an installment area of a ground or floor surface  50  ( FIG. 6 ). The fasteners  162  may be bolts, anchors, or other connectors. A respective annular countersink recess may surround each hole  160  to accommodate a bolt head. Once the grounding assembly  100  is placed as desired, the fasteners  162  are secured into the ground or floor surface  50  to both mechanically secure and electrically ground the assembly  100  and to stabilize the top plate  108 . In  FIG. 7 , additional holes  164  are shown as formed through the floor  102  and side-wall sections  104  to accommodate additional fasteners  166 . Additional holes  164  may also be formed to permit drainage in the event liquid such as rain or other work fluids enter the grounding assembly  100 . 
       FIG. 6  is an elevation view of the grounding assembly of  FIG. 1  installed below or flush with a floor or ground surface and showing a view of a reel assembly  132  from which a grounding cable  130  is deployed through the open top-side access panel  110 . The grounding assembly  100  can be installed in a surface near where aircraft or other vehicles and equipment are to be grounded. For use in electrically grounding a vehicle such as an aircraft while fueled and serviced, each grounding cable  130  can be extended from its respective reel assembly  132 . Conveniently, each grounding cable  130  can be returned to its respective reel assembly  132  for safe storage when not in use. 
       FIG. 8  is a plan view of the top side of the lower housing of the grounding assembly, according to at least one embodiment. In this example, the lower housing  101  has a flange  144  that extends outward parallel to the top plate  108  when assembled. The flange  144  has holes  146  to receive or permit passage of the fasteners  162  ( FIG. 1 ) when fixing the grounding assembly  100  in an installment area of a ground or floor surface  50  ( FIG. 6 ). The holes  146  in the flange  144  are respectively positioned to align with the holes  160  in the top plate  108  ( FIG. 1 ) so as to receive fasteners  162 . When so installed, the flange  144  is trapped between ground or floor surface  50  and the lip  120  of the top plate  108 . 
     The top plate  108  is shown as circular in  FIGS. 3-4 . Other shapes are used in other embodiments. In at least one particularly advantageous embodiments, the top plate is circular and has a diameter of approximately eighteen inches complying with, for example, military specifications for grounding points. For example, the top plate  108  and access panel  110  may be painted or otherwise colored yellow. 
     As described above, the grounding assembly  100  provides for the grounding of an aircraft and other vehicles and equipment with below surface storage of the grounding cables  130  and electrical contact  134 . Installation can be made in locations where grounding is needed. The grounding assembly  100  minimizes the labor in deploying a grounding cable and minimizes the likelihood of vehicles driving over the cables. 
     Particular embodiments and features have been described with reference to the drawings. It is to be understood that these descriptions are not limited to any single embodiment or any particular set of features, and that similar embodiments and features may arise or modifications and additions may be made without departing from the scope of these descriptions and the spirit of the appended claims. Features shown in at least one of the drawings may be optionally considered as present in each other drawing whether expressly illustrated or not. These descriptions and the drawings are to be viewed as cumulative.