Abstract:
An electrical grounding strip has a first link and a second link, wherein the second link is connected directly to the first link, and each of the first and second links has a portion lying substantially in a plane and has at least one electrically conductive spike attached to the portion. The spike projects generally orthogonally to the plane of the link portion. An electrically conductive ground strap is in electrically conductive contact with the spikes of each of the first and second links.

Description:
FIELD OF THE INVENTION  
       [0001]    The present invention relates generally to devices for electrical grounding and in particular to devices for electrical grounding for use with mobile electrical equipment. 
       BACKGROUND OF THE INVENTION  
       [0002]    Electrical systems such as radar and communication systems require grounding. One known method (shown in  FIG. 1 ) for grounding mobile electrical systems such as radar and communication systems has been to use a single grounding rod  110 . The single grounding rod may be, for example, about eight feet long, and is driven into earth. Rod  110  is clamped to cable  112  by clamp  114 , and has a connector  116  for being applied to a ground attachment of a device. One shortcoming of this method is that it is very difficult to use for rapidly deploying systems because it requires considerable crew effort and time to install the grounding rod. Another shortcoming is that such a rod is not re-usable because considerable time and energy would be required to completely pull out the grounding rod. 
         [0003]    Another known method for grounding mobile radar and communication systems is to use a grounding kit, illustrated in  FIG. 2 . Such a grounding kit consists of a number of daisy chained stakes  210 , about 10″ (inches) long, all of which have to be installed by hand in a desired pattern. Each stake has to be individually forced into ground with the use of a hammer  220  and like tools. The stakes  210  are then connected to each other through a grounding cable  240 , which is further connected to ground an electrical system  230 . This requires substantial crew effort and time to drive each of the grounding stakes into the ground around the deployed system. Similarly, when the electrical equipment is to be redeployed or removed, all of the stakes have to be removed manually. This requires considerable crew effort and time because each stake has to be individually pulled out of the ground. It would be desirable to provide for decreased installation and removal time, both in overall time and personnel time, for devices to ground electrical equipment. This can facilitate, by way of example, deploying mobile radar, communications and other electrical systems. 
       SUMMARY OF THE INVENTION  
       [0004]    An electrical grounding strip includes a first link connected directly to a second link. Each of the first and second links has a portion lying substantially in a plane and has at least one electrically conductive spike attached to the portion. The spike projects generally orthogonally to the plane. An electrically conductive flexible member, which is in electrically conductive contact with the spikes of each of the first and second links, grounds the mobile electrical system. 
         [0005]    A method for grounding equipment includes the step of placing a strip made of a first and a second link, each of the first and second links having a planar portion and at least one spike which projects generally orthogonally from the planar portion, in a position such that each of the spikes of the first and second links is pointing toward a grounding surface, electrically connecting each of the spikes to the equipment and applying a load to each link to force each of the spikes into the grounding surface. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES  
         [0006]    Understanding of the present invention will be facilitated by consideration of the following detailed description of the preferred embodiments of the present invention taken in conjunction with the accompanying drawings, in which like numerals refer to like parts and in which: 
           [0007]      FIG. 1  illustrates a prior art device for grounding electrical equipment; 
           [0008]      FIG. 2  illustrates a prior art system for grounding a mobile electrical system; 
           [0009]      FIG. 3  illustrates an electrical grounding strip according to an embodiment of the invention; 
           [0010]      FIG. 4A  illustrates a link of the grounding strip of  FIG. 3 ; 
           [0011]      FIG. 4B  illustrates a direct connection between two links of the grounding strip of  FIG. 3 ; 
           [0012]      FIGS. 5A and 5B  illustrate a method of driving spikes of the grounding strip of  FIG. 3  into a grounding surface; 
           [0013]      FIG. 6  illustrates lodging of spikes of the strip of  FIG. 3  in a grounding surface and removal of the strip; and 
           [0014]      FIG. 7  illustrates an electrical system grounded employing electrical grounding spike strips in accordance with an embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0015]    It is to be understood that the figures and descriptions of the present invention have been simplified to illustrate elements that are relevant for a clear understanding of the present invention, while eliminating, for purposes of clarity, many other elements found in typical grounding methods and systems. However, because such elements are well known in the art, and because they do not facilitate a better understanding of the present invention, a discussion of such elements is not provided herein. The disclosure herein is directed to all such variations and modifications known to those skilled in the art. 
         [0016]    Referring to  FIG. 3 , there is shown an electrical ground spike strip  300  in accordance with an embodiment of the invention. The spike strip  300  has two links  310 ,  320  which are connected directly and rotatably to each other. Each of the links  310 ,  320  has two spikes  315  each. Dependant upon the final configuration of the spike strip  300 , additional links  310  may be added to provide the required grounding. The link  310  with two spikes  315  is only illustrative. Furthermore, it is possible to have one or more than two spikes on each link  310 , as will be easily understood by a person of skill in the art. The spike strip  300  also includes a handle  340  which is directly and rotatably connected to link  310 . A flexible, electrically conductive, grounding strap  320  is in electrically conductive contact with each of spikes  315  of the links  310 ,  320 , and may be provided in electrically conductive contact to the equipment which is to be grounded. In the illustrated embodiment, each of links  310 ,  320  is made of a single piece of electrically conductive material, so that the illustrated physical connection between strap  320  and links  310 ,  320  provides electrically conductive connection with spikes  315 . 
         [0017]    Now referring to  FIG. 4A , the link  310  is shown in greater detail. Three segments  311 ,  312  and  313  form a portion  317  of the link  310 . The portion  317  lies substantially in a plane. In this illustrative only embodiment, the three segments  311 ,  312  and  313  define a generally rectangular frame. Segments  311  and  312  are generally straight and generally parallel to each other, defining two opposite sides of a rectangle. In this illustrative embodiment, segment  313  has a central portion  318  which is generally straight and two curved outward extending portions  314 . Segment  311 , at its end opposite to segment  313 , joins an upper end of one of spikes  315 . Segment  311  defines loop or coil  316  of about 450 degrees. An opening defined in the center of coil  316  is sufficiently large to receive a rod of the same size. Portions  314  may be received within coils  316 . As an exemplary embodiment only, the spikes  315  may be about 8″-12″ long. The spikes  315  are slightly curved inward toward the portion  317 . Each spike has an elongated main portion of uniform diameter, and tapers to a point at a distal end thereof, opposite to the end connected to planar portion  317 . 
         [0018]    In the illustrated embodiment, the three segments  311 ,  312  and  313 , and spikes  315 , are formed from a single elongated and shaped cylindrical rod. However, other manufacturing methods may be used to fabricate link  310 . By way of example, three segments can be joined to form the portion  317 , and the spikes joined to the portion  317 , or a single elongated member can be shaped to form the link  310 , including spikes  315 , by bending, or casting or other manufacturing processes. It will be appreciated that coils  316  may be formed around portions  314  of adjoining links when spike strip  300  is formed. As seen in  FIG. 4B , in this particular embodiment of the link connection, the coiled portions  316  of the spikes  315  are wrapped around the curved portions  314  of the member  313  to connect the link  320  with the link  310 . The connection between the links  310  and  320  is pivoting or rotatable connection. Various other known joints can also be used to connect the link  310  with the link  320 . In the illustrated embodiment of the invention in  FIGS. 3 and 4B , the links  310  and  320  are identical. 
         [0019]    Handle  340 , shown in  FIG. 1 , has a generally rectangular frame, defined by straight side segments  341 ,  342 , connecting end segment  343 , and gripping end segment  344 . Handle  340  lies in a plane. Connecting end segment  343 , similar to segment  313  of link  310  (described above in connection with  FIG. 4A ), is generally straight with outward curving portions, that are received in coils  316  of link  310 . Handle  340  is thereby rotatably connected to link  310 . When strip  300  is in the ground, handle  340  may lie flat on the ground. 
         [0020]    Illustrated in  FIGS. 5A and 5B , is a method for grounding equipment using the rollover electrical spike strip  300 . The strip  300  is laid on ground  510  in a desired pattern, with spikes  315  of the links  310 ,  320  pointing toward the ground  510 . Spikes  315  are in contact with the ground  510 , and are substantially supporting strip  300 . A load is then moved onto spike strip  300 . In one embodiment, the load may be a wheeled vehicle, having wheel  500 . The wheeled vehicle may be a self-propelled, motorized vehicle. The motorized vehicle may alternatively be a tracked vehicle. As the wheel  500  rolls over the strip  300 , it forces the spikes  315  into the ground  500 . In  FIG. 5A , link  310  is positioned so that segment  313  and points of spikes  315  are generally in contact with the ground. As spikes  315  are curved toward planar portion  317 , the points of spikes  315  are substantially orthogonal to the ground. As wheel  500  moves forward, link  310  is rotated so that spikes  315  are driven into the ground. As the spikes of link  310  are driven into the ground, coils  316  of link  310  are moved to the ground. Segment  313  of link  320 , which is disposed through coils  316  of link  316 , is thus moved closer to the ground, causing link  320  to rotate such that the planar portion  317  of the link  320  is positioned tangentially to the wheel  500  and spikes  315  of link  320  are pointed closer to orthogonal to the ground, as shown in  FIG. 5B . As portion  317  is planar, wheel  500  may easily continue rolling once spikes  315  of link  310  have been completely driven into the ground. The wheel  500  then rolls over the link  320 , and forces the spikes  315  of the link  320  into the ground. Similarly, as the spikes of each link are forced into the ground, the planar portion  317  of the subsequent link becomes tangential to the wheel  500 , and spikes  315  of the subsequent link are oriented closer to orthogonal to the ground. Since all the spikes  315  are electrically connected by the ground strap  330  (of  FIG. 3 ), the equipment is grounded when the ground strap is connected to the equipment. 
         [0021]    Now referring to  FIG. 6 , the entire strip  300  is shown after each of spikes has been driven into the ground. All of the spikes  315  are lodged firmly into the ground. The handle  340  can be used to pull the strip  300  out of the ground when the strip is no longer needed, such as when the equipment is being moved again. Gripping segment  344  of handle  340  may be engaged and pulled upward, so that initially handle  340  rotates about its connection to link  310 . As a user continues to apply a manual or mechanical force to gripping segment  344 , link  310 , and then successively the remaining links, are pulled out of the grounding surface. 
         [0022]      FIG. 7  illustrates an electrical system  700  grounded employing electrical grounding spike strips in accordance with an embodiment of the invention. A wheeled vehicle  710 , having wheels  500 , carries an electrical device  700 , which includes a radar array  710  in this example. Four electrical grounding spike strips  300  are deployed, with the spikes  315  of each firmly lodged into the grounding surface  510 , providing good electrical contact between the spikes and the grounding surface. Grounding strap  330  is electrically connected to each spike strip  300  and to attachment  720  for grounding device  700 . Thus, device  700  is grounded. 
         [0023]    An exemplary advantage of a ground strip in accordance with an embodiment of the invention is that, since the weight of a vehicle is used to embed the spikes in the ground, significant savings in crew effort and time are achieved in providing for grounding of mobile electrical devices when compared with the methods illustrated in  FIGS. 1 and 2 . A further exemplary advantage is that significant savings in crew effort and time are achieved in removing a spike strip in accordance with an embodiment of the invention from the ground. The use of a spike strip in accordance with an embodiment of the invention thus facilitates rapid deployment of mobile electrical systems. It is further advantageous that a grounding strip in accordance with an embodiment of the invention is reusable. 
         [0024]    It will be apparent to those skilled in the art that modifications and variations may be made in the apparatus and process of the present invention without departing from the spirit or scope of the invention.