Patent Abstract:
An enclosure for an electrical connection between two high-voltage cables that includes an electrically nonconductive separator integral with a mounting base for receiving the high-voltage cables. An electrically nonconductive tubular cover extends over the electrical connection and the high-voltage cables and is releasably attached to the base. The separator has at least two resiliently mounted fingers, and the electrically nonconductive cover extends over the fingers to depress and move the fingers into contact with the high-voltage cables, thereby securing the high-voltage cables in the mounting base. The high-voltage cables are extended beyond the mounting base a distance equal to a desired spacing separating the electrical connection between the high-voltage cables and an electrical conductor associated with the mounting base. The tubular cover is transparent so that the electrical connection joining the high-voltage cables can be visually inspected through the cover.

Full Description:
FIELD OF THE INVENTION 
     The present invention generally relates to an high-voltage connection enclosure and more particularly, to an improved enclosure for connecting high-voltage cables connected to high-voltage gas-filled tubes, for example, neon tubes used for signage. 
     BACKGROUND OF THE INVENTION 
     High-voltage, gas-filled tubes have been widely used for signage for decades. Some neon signage has the gas-filled tubes depicting letters and numbers completely enclosed in a housing that protects the electrical components and electrical connections from the weather. With other sign constructions, the sign is composed of individual gas-filled tubes representing letters and numbers that are individually mounted to an exterior wall or other surface of a structure without the benefit of an enclosure over all of the components. In that construction, the individual gas-filled tubes must be wired together in a high-voltage circuit that is powered from a secondary winding of a transformer. In a known manner, the wire from a gas-filled neon tube has an electrode that is connected to a conductor or wire, for example, a high-voltage gaseous tube and oil ignition (“GTO”) cable. In many applications, the electrical connection between the neon tube electrode and one end of the high-voltage GTO cable is accomplished utilizing a known connector P-K connector. The other end of the GTO cable is then connected to either one side of the secondary winding of the transformer or an electrode of an adjacent gas-filled neon tube. Thus, the gas-filled neon tubes are connected in series with the secondary winding of the transformer. In some applications, a single GTO cable is connected to adjacent gas-filled tubes. While such a connection would seem to be efficient, since the PK connectors are often located within a wall of the structure, the diagnosis and correction of a fault is time consuming and difficult. In other applications, a GTO cable from one gas-filled tube is connected or spliced with a GTO cable from an adjacent gas-filled tube in a junction box. Such known junction boxes have at least one electrically conductive terminal to which the ends of both GTO cables are mechanically connected and secured, thereby electrically connecting the GTO cables together. Other terminal boxes have two electrically conductive terminals connected with a electrically conductive bar, and an end of each of the GTO cables is attached to one of the terminals. 
     Such junction boxes permit gas-filled neon tubes to be very easily connected together. In some applications, the P-K connectors extend through the exterior wall of a building; and the junction boxes are in a relatively protected environment. In other applications, the P-K connectors and the junction boxes are mounted on the exterior wall of the building, and thus, must be impervious to harsh weather conditions. 
     Of significant concern is the potential for arcing or a short circuit between the exposed ends of the GTO cable and any grounded metal component within the junction box. To minimize the potential for arcing within the junction box, regulations are implemented setting forth a minimum distance between a cable connection and a metal portion of the junction box. Over the years, the specified minimum distance has increased, and more recent regulations may require different minimum distances depending on whether the junction box is located inside or outside a structure. Operating in an environment in which the regulations constantly change is a particular challenge with respect to the junction box design. 
     Further, there is a continuing requirement to make junction boxes more reliable and easier to use. For example, some junction box designs have various loose parts that must be assembled in the process of splicing two cables together. Further, after the cable splice is made and the junction box is permanently mounted, all junction boxes are opaque; and therefore, the junction box must be opened or partially disassembled to check the integrity of the splice. 
     Therefore, there is a need for an improved enclosure for connecting the ends of high-voltage GTO cables that can be readily changed to meet regulations that are constantly changing. Further, there is a need for a junction box that permits the integrity of the splice to be checked without having to disassemble the junction box. Further, there is a need for a junction box design that is easier to handle in the connecting of the GTO cables. 
     SUMMARY OF INVENTION 
     The present invention provides a high-voltage connection enclosure that is less susceptible to arcing and short circuits that may potentially result in a fire. The enclosure of the present invention is easy to use and permits a visual inspection of the electrical connection between two GTO cables without having to remove a cover or in any way disassemble the enclosure. Further, the enclosure of the present invention automatically secures the GTO cables in the enclosure as an enclosure cover is attached. Thus, the present invention provides a more consistent, reliable and higher quality, high-voltage electrical connection between ends of GTO cables. The invention is especially useful in providing an electrical connection with a high-voltage, gas-filled tube used for signage in which the electrical connection is exposed to a wide range of temperature and moisture conditions. 
     In accordance with the principles of the present invention and the described embodiments, an apparatus is provided for enclosing an electrical connection between two high-voltage cables. The apparatus has an electrically nonconductive separator integral with a mounting base for receiving the high-voltage cables. An electrically nonconductive tubular cover extends over the electrical connection and the high-voltage cables and is releasably attached to the mounting base. 
     In one aspect of the invention, the separator has two passages in a base portion to separately receive the high-voltage cables. The high-voltage cables are extended beyond the mounting base, so that the electrical connection is separated from an electrically conductive portion of the mounting base by a desired spacing. The separator also has fingers that are moved by the tubular cover into contact with the high-voltage cables to secure the high-voltage cables in the separator. 
     In a still further aspect of the invention the electrically nonconductive cover is sufficiently transparent so that the electrical connection joining the high-voltage cables can be visually inspected through the cover. 
     In another embodiment, the present invention includes a method of electrically connecting two high-voltage cables by first inserting each of the high-voltage cables into a separate passage formed of a nonconductive material integral with a mounting base. Next the high-voltage cables are extended a distance beyond the mounting base equal to a desired separation between an electrical connection between the cables and an electrical conductor associated with the mounting base. The ends of the high-voltage cables are joined together to form the electrical connection; and then, an electrically nonconductive tubular cover is placed over the electrical connection and the high voltage cables and is releasably attached to the mounting base. 
     In an aspect of that invention, the method further comprises securing the high-voltage cables in the mounting base. 
     Various additional advantages, objects and features of the invention will become more readily apparent to those of ordinary skill in the art upon consideration of the following detailed description of the presently described embodiments taken in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS 
     FIG. 1 is a disassembled perspective view of a high-voltage connection enclosure in accordance with the principles of the present invention. 
     FIG. 2 is a top view of the assembled high-voltage connection enclosure illustrated in FIG.  1 . 
     FIG. 3 is a schematic block diagram of a circuit illustrating the use of the high-voltage connection enclosure illustrated in FIG.  1 . 
     FIG. 4 is an enlarged cross-sectional view taken along line  4 — 4  of FIG.  2  and illustrates the locking of GTO cables in the high-voltage connection enclosure illustrated in FIG.  1 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to FIG. 1, the high-voltage connection enclosure  20  is comprised of a mounting base  22 , a mounting base bracket  24 , a separator  26 , a cover or tubular body  28  and a tube clamp  30 . The mounting base  22  has two opposed cavities  32 ,  34  that have generally circular outer wall portions that are sized to receive flexible metal cable that is typically used. The cavities  32 ,  34  have a depth that permit the metal flexible conduit to be inserted until it hits a rear surface  33  of a top wall  36  of the mounting base  22 . Mounting legs  38  extend laterally away from the rear side  40  of the mounting base  22  and have mounting feet  42  formed on their distal ends. The mounting feet  42  have through holes  44  that accept fasteners for attaching the mounting base  22  to a surface. A hollow cylindrical tube mount  46  extends from the top  48  of the mounting base  22 . The tube mount  46  is equally spaced between the cavities  32 ,  34 , and the tube mount  46  has a cylindrical through bore  47  intersecting the cavities  32 ,  34 . The front side  50  of the mounting base  22  has a clearance hole  52  for receiving a fastener  54  that threadedly engages a hole  56  within the bracket  24 . The cavities  32 ,  34  have an extension or hood  58  on the front side  50  of the mounting base  22 . The mounting base bracket  24  is located immediately below the extension  58  and has ears  60 ,  62  for engaging and locking into grooves in the metal flexible conduit disposed in the respective cavities  32 ,  34 . 
     The separator  26  has a spacer wall  66  extending from a base portion  68 . The separator  26  is located in the mounting base  22  and through the tube mount  46  at an orientation such that the spacer wall  66  is substantially perpendicular to a line joining the centers of the cavities  32 ,  34 . In other words, the spacer wall  66  bisects the internal bore  47  of the tube mount  46  along a diameter bisecting the top and bottom sides  50 ,  40 , respectively, of the mounting base  22 . The base  68  of the separator  26  has a retaining flange or lip  70  with diametrically opposed locating tabs  72 ,  74 . The spacer wall  66  extends through the base  68  and has a bottom end  76  formed with the retaining lip  70 . A segmented bushing  82  is formed with the retaining lip  70  and has a plurality of through slots  84  between segments  86  to permit radially inward motion of the segments  86  during the mounting of the separator  26  within the mounting base  22 . A plurality of locking teeth or fingers  88  are formed on an inner end of the segmented bushing  82 . The plurality of fingers  88  are cantilevered from the retaining ring  70 , and each of the fingers  88  along with a corresponding bushing segment  86  is resiliently, pivotable with respect to the retaining ring  70 . Therefore, the fingers  88  are independently movable in a generally radial direction with respect to the generally cylindrical bushing  82 . The slots  84  extend between the locking fingers  88  to facilitate a radially inward deformation of the locking fingers  88  in the assembly process. 
     To assemble the separator  26  in the mounting base  22 , the spacer wall  66  is inserted into the bore  47  of the tube mount  46  from the mounting base bottom side  35 . Upon the fingers  88  contacting an edge of the bore  47  of the tube mount  46 , angled surfaces  90  of the fingers  88  facilitate compression of the fingers in response to an axial force being applied against the bottom surface  76  of the retaining lip  70 . As the plurality of fingers  88  and bushing segments  82  move radially inward, the plurality of fingers  88  slide through the bore  47  of the tube mount  46 . As shown in FIG. 1, two opposed projections  89  are aligned with and extend radially from opposite edges  91  of the spacer wall  66 . The projections  89  are radially smaller than the fingers  88  and normally pass through the bore  47  without contacting the walls of the bore  47 . The axial length of the segmented bushing  82  is slightly larger than the axial length of the tube mount  46  (FIG.  2 ). Therefore, as the locating tabs  72 ,  74  contact the inside surface  33  of the front wall  36 , the plurality of fingers  88  pass the top edge  92  of the tube mount  46  and expand radially outward. The top edge  92  of the tube mount  46  locks behind the plurality of fingers  88 , thereby permanently locking the separator  26  into the mounting base  22  and forming an integral unit therewith. The fingers  88  have a length such that they extend radially beyond a cylindrical outer surface  93  of the tube mount  46 . Referring to FIG. 1, the ends of the tabs  72 ,  74  are sized to contact an inner, generally spherically shaped portion of the front wall  36  of the mounting base  22 , thereby preventing the separator  26  from rotating within the mounting base  22 . 
     The tubular body or tube  28  has a closed end  100  and an annular flange  102  at its opposite open end  104 . The tube  28  has an inner, generally cylindrical cavity  105  with a diameter that is slightly larger than the outer diameter of the tube mount  46 . However, the diameter of the cavity  105  is slightly smaller than a diameter extending across the fingers  88 . The spacer wall  66  of the separator  26  as assembled in the mounting base  22  extends outward from the tube mount  46 . After electrically connecting the GTO cables as will be described, the assembly of the high-voltage connection enclosure  20  is completed by sliding the tube  28  over the separator  26 , over the fingers  88  and securing the tube  28  against the mounting base  22  with a tube clamp  30 . Thus, the tube  28  completely encloses the spacer wall  66  and depresses the fingers  88  slightly radially inward. The tube clamp  30  has a cylindrical tubular body  110  that slides over an outer, generally cylindrical surface of the tube  28 . The tube clamp body  110  has an annular bottom edge  112  that contacts an annular top surface  114  of the flange  102  of the tube  28 . The tube clamp  30  also has two diametrically opposed spring arms or clips  116  that are pressed together to cause the arms to extend, thereby permitting ends  118  of the arms  116  to be located in notches  120 , thereby securing the tube  28  to the mounting base  22 . The fully assembled high-voltage connection enclosure  20  is shown in FIG.  2 . 
     Referring again to FIG. 1, the spacer wall  66  extends through and generally bisects the segmented bushing  82  and the retaining lip  70  to form two generally semicircular passages or through holes  96 ,  98 . Passage  96  extends through the retaining lip  70  and the segmented bushing  82  of the base  68  and opens to one side  97  of the spacer wall  66 . Passage  98  similarly extends through the retaining lip  70  and the segmented bushing  82  of the base  68  and opens to an opposite side  99  of the spacer wall  66 . 
     The mounting base  22  and bracket  24  are normally made from an electrically conductive material, for example, a cast zinc. The electrically conductive material is chosen for reasons of cost and physical strength. The separator  26  is normally made from an electrically nonconductive material, for example, a “LEXAN”  503  plastic material; however as will be appreciated other electrically nonconductive materials may be used. The tubular body  28  is also made from an electrically nonconductive material, for example, a clear or transparent glass; but as will be appreciated, other electrically nonconductive materials may be used. 
     In use, referring to FIG. 3, the high-voltage connection enclosures  20  are typically used in a serial circuit with high-voltage, gas-filled tubes  122 , for example, neon tubes. Each end of the gas-filled tubes  122  has an electrode that is connected to a GTO cable  126 ,  128  inside a PK connector  130 . The gas-filled tubes  122  are wired together in a serial circuit that is powered from a secondary winding from a transformer  124 . Thus, the first and last gas-filled tubes  122  have one electrode connected to first ends of GTO cables  126 . In a known manner, the GTO cables  126  are normally routed through sections of conduit  129 , for example, a flexible metal conduit; and the opposite ends of the GTO cables  126  are connected to a secondary winding of a transformer  124 . The other electrodes of the gas-filled tubes  122  are connected via GTO cables  128  that are routed in respective sections of conduit  131  and connected together in a junction box, for example, the high-voltage connection enclosure  20 . 
     In making an electrical connection or a splice, the tube clamp  30  is disengaged; and the tube clamp  30  and tube  28  are removed from the mounting base  22 . Further, the fastener  54  is loosened to loosen the mounting base bracket  24 . Referring to FIGS. 1 and 2, a length of GTO cable  132  extending from the end of one of the metallic flexible conduits  134  is inserted into the cavity  32  through the first passage  96  and along the one side  97  of the spacer wall  66 . A length of the GTO cable  132  should extend beyond the distal end  136  of the spacer wall  66 . In a similar manner, a second GTO cable  138  extending from the end of a metallic flexible conduit  140  is threaded through the cavity  34 , the second passage  98  and along the opposite side  99  of the spacer wall  66 . Again, a length of GTO cable  138  should extend beyond the distal end  136  of the spacer wall  66 . Referring to FIG. 4, it should be noted that the cavities  96 ,  98  are nominally sized such that the outer surfaces of the GTO cables  132 ,  138  just touch the respective opposite sides  97 ,  99  of the spacer wall  66  and the respective opposed inner surfaces  101 ,  103  of the respective fingers  88   a ,  88   b . Referring to FIG. 2, the conduits  134 ,  140  are then inserted in the respective cavities  32 ,  34 , and the fastener  54  is tightened, Tightening the fastener  54  clamps the mounting base bracket  24  tightly against the conduits  134 ,  140 . The ears  60 ,  62  on the bracket  24  engage or penetrate an external feature of the conduits  134 ,  140 , thereby more firmly securing the conduits to the mounting base  22 . For example, if the conduits  134 ,  140  are metal flexible conduits, the ears  60 ,  62  lock into helical grooves extending over an exterior surface of the metal conduits  134 ,  140 . As the fastener  54  is tightened and the mounting base bracket brought up against the conduits  134 ,  140 , a rearward extending flange or cover  141  of the bracket  24  functions to cover the cavities  32 ,  34 . The ends of the respective GTO cables  132 ,  138  extending beyond the distal end  136  of the spacer wall  66  are stripped to bear respective conductors or wires  142 ,  144 . The wires  142 ,  144  are twisted together or otherwise joined with an electrical connector to form a high-voltage electrical connection  146  beyond the distal end  136  of the spacer wall  66 . 
     Thus, the separator  26  performs several functions. First, the openings  96 ,  98  provide paths for the GTO cables through the mounting base  22  that protect the cables from scuffing or physical damage from any edges or other physical features of the mounting base  22 . Further, the separator spacer wall  66  has a length that guarantees a spacing or separation between the high-voltage electrical connection  146  and any metal components, for example, the front wall  36  of the mounting base  22 . That separation or spacing is often determined by UL regulations. Further, different spacing or separations are readily obtained by simply changing the length of the spacer wall  66  and the tube  28 . In addition, the spacer wall  66  provides mechanical support for the high-voltage connection  146  immediately adjacent its distal end  136 . 
     After the high-voltage electrical connection  146  is made, the clear tubular body  28  is slid over the connection  146 , the GTO cables  132 ,  138 , spacer wall  66  and the fingers  88 . The inner diameter of the cavity  105  of the tubular body  28  is slightly smaller than a diameter extending across the fingers  88 . Therefore, referring to FIG. 4, as the cylindrical inner surface  107  of the tubular body  28  is slid over the fingers  88 , the fingers  88  are deflected or forced radially inward. A lower corner or edge surface  101  at the intersection of the tooth  88   a  with its corresponding segment  86   a  is pushed into the outer surface of the cable  132 . That deflection of the tooth  88   a  and segment  86   a  functions to lock the cable in the cavity  96  and resists forces on the cable  132  occurring in a direction toward the viewer of FIG. 4. A lower corner or edge surface  103  at the intersection of the tooth  88 b with its corresponding segment  86   b  is pushed into the outer surface of the cable  138 , thereby locking the cable  138  in the cavity  98 . 
     Upon sliding the tubular body  28  over the fingers  88 , the bottom surface  106  on flange  102  of the tubular body  28  contacts a forward surface  108  on the mounting base  22 . Thereafter, the cylindrical body  110  of the tube clamp  30  is slid over the tubular body  28  until the bottom edge  112  of the cylindrical body  110  contacts an upper annular surface  114  of the flange  102 . The spring arms  116  are then manually compressed until the arm ends  118  slide into the locking notches  120 . Upon releasing the spring arms  116 , the ends  118  of the spring arms  116  are secured in the notches  120 , thereby securing the tubular body  28  to the mounting base  22 . If not already permanently mounted, the mounting base is then mounted on a wall with the clear tubular body pointing in the vertically upward direction. 
     The high-voltage connection enclosure  20  provides a connection enclosure for interconnecting high-voltage, gas-filled tubes that is less susceptible to arcing and short circuits which may lead to a fire when exposed to a wide range of temperature and moisture conditions. With the high-voltage connection enclosure described herein, the separator  26  is fixed in the mounting base  22 ; and therefore, routing the GTO cables and making the electrical connection is very easy. Further, the clear glass tubular cover not only provides superior, long term electrical insulating capability, but the clear cover permits an immediate visual inspection of the electrical connection without having to remove a cover or disassemble the enclosure in any way. Being able to quickly determine the mechanical integrity of the electrical connection makes diagnostic and maintenance procedures much less time consuming and more efficient. Thus, the high-voltage connection enclosure provides a consistent, reliable and high quality, high-voltage electrical connection between ends of GTO cables. 
     While the present invention has been illustrated by a description of various described embodiments and while these embodiments have been described in considerable detail, it is not the intention of Applicant to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications within the spirit and scope of the invention will readily appear to those skilled in the art. For example, in the described embodiment, the tubular body  28  is described as a generally cylindrical body which has a generally circular cross-sectional shape. As will be appreciated, the tubular body  28  may have any cross-sectional shape, for example, noncircular or multilateral. Further, the tubular body is described as being secured by a spring clamp  30 ; however, as will be appreciated, the tubular body may be secured to the mounting base  22  by other means, for example, a threaded connection. Further, the tube clamp  30  may be made from a metal, plastic or other material that provides the necessary function. In addition, as will be appreciated, in the assembly of the tubular body  28  onto the mounting base  22 , it may be desirable to mounted the end  106  of the tubular body  28  against an O-ring located over the circular mount  46  and against the forward surface  108 . 
     Further, in the described embodiment, the separator  66  is secured to the mounting base  22  by resilient fingers  88  to form a unitary structure with the mounting base. While a plurality of circumferentially arranged fingers  88  is described, a single or any number of fingers may be used. In addition, as will be appreciated, instead of using the fingers  88 , the separator  26  may be connected to the mounting base  22  by adhesives, welding, threads or other means. Alternatively, the mounting base  22  and separator  26  may be manufactured as a single unitary structure. 
     The description of the tubular body  28  as being clear glass means that the tubular body is sufficiently translucent or transparent so that the electrical connection may be visually inspected through the cover. Alternatively, the tubular body may also be opaque although the advantage of visual inspection will be lost. As will be further appreciated, even though glass has excellent long term electrically insulation properties, the tubular body  28  may be made of other electrically nonconductive materials. 
     Therefore, the invention in its broadest aspects is not limited to the specific detail shown and described. Consequently, departures may be made from the details described herein without departing from the spirit and scope of the claims which follow.

Technology Classification (CPC): 8