Abstract:
Quick-connect disconnect connectors are provided as part of an electrical assembly used to electrically couple components to the end of an electrical track section. The connectors have a tongue portion insertable into the end of the track only one way to ensure against cross-wiring and include structures for retaining electrical contacts and strain reliefs. The connectors readily disconnect from the end of the track when force is applied which might be sufficient to damage the track or electrical assembly to prevent such damage.

Description:
CROSS-REFERENCED TO RELATED APPLICATIONS 
       [0001]    Not applicable 
       STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0002]    Not applicable 
       BACKGROUND OF THE INVENTION 
       [0003]    I. Field of the Invention 
         [0004]    The present invention relates generally to lighting systems for display cases and shelving units used by merchants. More specifically, the present invention relates to quick-connect and disconnect connectors forming a part of such lighting systems which ensure that no cross-wiring occurs during the assembly process. 
         [0005]    II. Related Art 
         [0006]    Various forms of lighting have been employed in retail establishments. Lighting is used on signage, to provide security, to accent and better display product features, to enhance the prominence and attractiveness of merchandise, and to affect the mood of customers. The eye is drawn to brighter areas of contrasting light. Reading of packaging and labeling is easier in well lighted areas. 
         [0007]    Many retail establishments employ overhead ambient light sources and shelving units for holding merchandise. The shelving units incorporate a plurality of vertically arranged shelves. These shelves are relatively deep and opaque such that the shelves of the shelving unit cast shadows upon or otherwise limit light from reaching merchandise stored on all but the top shelf of the shelving unit. Further, such lighting and shelving units are bland and do not serve to “catch the eye” of the retail customer and do little to attract a customer to a particular item of merchandise. 
         [0008]    Various lighting systems for shelving units have been employed to overcome these deficiencies, but they are often costly, laborious to assemble, and involve numerous electrical connections which must be made after the shelving unit is completely assembled. Further, such electrical connections typically must be taken apart before the shelving unit can be disassembled to prevent damage to the shelves, light fixtures or electrical contacts. Substantial skill and effort is required to assemble and disassemble such prior art lighting systems. If sufficient care is not exercised, such prior art lighting systems increase the risk of electrical shock or even fire. Substantial routing of wires from light fixtures to sources of electricity is required. One undesirable aspect of many such lighting systems is that, after installation, dangling wires detract from achieving the desired effect. The need therefore exists for wiring harnesses and connectors that overcome these deficiencies. 
       SUMMARY OF THE INVENTION 
       [0009]    The present invention is used in conjunction with shelving units which comprise a base, one or more back members extending vertically from the base, and at least one shelf secured to the back members and extending normally therefrom. Typically, the shelving units include a plurality of shelves supported by the back members in spaced, vertical arrangement. The present invention concerns electrical assemblies such as wiring harnesses and connectors used to install lighting systems on such shelving units. More specifically, the electrical assemblies are used to couple electrical devices to a lighting track secured to the back members of the shelving unit and extending vertically from the base of the shelving unit toward the top of the shelving unit. The track has a channel and elongated opening running the length thereof and exposing the channel. Inside the channel, on opposite sides are two parallel conductors running substantially the length of the channel. One of the conductors serves as a positive conductor and the other conductor serves as a negative conductor. 
         [0010]    The wiring harnesses and connectors of the present invention are used to connect a power supply to the track. The connectors may also be used to connect light fixtures mounted to the underside of the individual shelves to the track. The connectors and wiring harnesses are also suitable for joining sections of the track together. The harnesses and connectors are also used to couple multiple electronic devices to the track. 
         [0011]    The connectors associated with the wiring harnesses are designed to ensure proper polarity of the wiring is maintained (i.e., the negative terminals are connected to the negative side of the circuit and the positive terminals are connected to the positive side of the circuit). Also, the connectors are all designed so they are quickly connected and held in place for use. However, when shelving is disassembled or individual shelves are moved, the wiring harness automatically disconnects from either the track or the electrical device (e.g., a power supply or light fixture) to prevent damage to the track, the wiring harness, and the electrical device. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    The foregoing features, objects and advantages of the invention will become apparent to those skilled in the art from the following detailed description and with reference to the following drawings in which like numerals and the several views refer to corresponding parts. 
           [0013]      FIG. 1  illustrates the base and back members of a shelving unit. 
           [0014]      FIG. 2  illustrates a plurality of shelves attached to the base and hack unit of a shelving unit. 
           [0015]      FIG. 3  illustrates a lighting system which may be used with the shelving units of  FIGS. 1 and 2 , 
           [0016]      FIG. 4  illustrates a back member of the shelving unit of  FIG. 1  or  2  together with a pair of lighting tracks joined together by a harness incorporating connectors of the present invention. 
           [0017]      FIG. 5  shows two pieces of track joined together by the harness of  FIG. 4 . 
           [0018]      FIG. 6  shows the same two pieces of track as in  FIG. 5  but with the harness removed, from the track. 
           [0019]      FIG. 7  shows a connector of a harness of the present invention aligned to be inserted in a section of track from the back side of the track. 
           [0020]      FIG. 8  shows the arrangement of  FIG. 7  with the connector inserted into the track. 
           [0021]      FIG. 9  shows a section of track with a connector of the wiring harness aligned for insertion into the track from the front side of the track. 
           [0022]      FIG. 10  shows the arrangement of  FIG. 9  with the connector inserted, into the track. 
           [0023]      FIG. 11  shows a track section coupled to an end cover having substantially the same design as the housing of the track connector of the present invention. 
           [0024]      FIG. 12  is a perspective view showing the hack of the connector of the present invention. 
           [0025]      FIG. 13  is a perspective view showing the front of the connector of the present invention. 
           [0026]      FIG. 14  is a perspective view showing the housing of the connector disassembled from the cover of the connector. 
           [0027]      FIG. 15  is a perspective view showing the housing of the connector of the present assembly disassembled from the cover of the connector, 
           [0028]      FIG. 16  is a perspective view of a wiring harness used to secure two pieces of track together. 
           [0029]      FIG. 17  is a perspective view of the arrangement shown in  FIG. 16  but with the wiring harness disassembled. 
           [0030]      FIG. 18  shows an alternative wiring harness with a track connector at one end and an alternative connector at the other end which may be used to join the connector to a power supply or other device. 
           [0031]      FIG. 19  is a perspective view of the arrangement shown in  FIG. 18  but with the track connector disassembled. 
           [0032]      FIG. 20  shows a wiring harness using the same track connector, but with a different connector to join the wiring harness to an electrical device. 
           [0033]      FIG. 21  shows the same arrangement shown in  FIG. 20  but with the track connector disassembled. 
           [0034]      FIG. 22  shows a wiring harness comprising a track connector and a pair of connectors, one male and one female, used to join one or a pair of electrical devices to a section of track. 
           [0035]      FIG. 23  shows the same arrangement as  FIG. 22  but with the track connector disassembled. 
       
    
    
     DETAILED DESCRIPTION 
       [0036]    This description of the preferred embodiment is intended to be read in connection with the accompanying drawings, which are to be considered part of the entire written description of this invention. In the description, relative terms such as “lower”, “upper”, “horizontal”, “vertical”, “above”, “below”, “up”, “down”, “top” and “bottom”, as well as derivative thereof (e.g., “horizontally”, “downwardly”, “upwardly”, etc.) should be construed to refer to the orientation as then described or as shown in the drawings under discussion. These relative terms are for convenience of description and do not require that the apparatus be constructed or operated in a particular orientation. Terms such as “connected”, “connecting”, “attached”, “attaching”, “joined”, and “joining” are used interchangeably and refer to one structure or surface being secured to another structure or surface or integrally fabricated in one piece unless expressly described otherwise. 
         [0037]      FIGS. 1 and 2  illustrate gondola-type shelving units  10 . The gondola-type shelving unit  10  has a base  12 , a lower back section  14 , and an upper back section  16 . The gondola-type shelving unit  10  also includes three vertical support members  18 ,  20  and  22  extending upwardly from the base  12 . The lower back section  14  includes a pair of panels  24  and  26  while the upper back section  16  includes panels  28  and  30 . As shown in  FIG. 2 , a plurality of shelves  32  are attached to and extend outwardly from the vertical support rails  18 - 22 . 
         [0038]      FIG. 3  shows a lighting assembly  40  particularly well suited for use with gondola-type shelving of the type shown in  FIGS. 1 and 2 . The lighting assembly  40  includes a track  42  which is coupled to a power supply  44  which, in turn, is coupled to an electrical outlet  46 . As such, the track  42  is energized by the power supply  44  and electrical outlet  46 . Also shown in  FIG. 3  is a plurality of light sources  48 . Each light source  48  is intended to be coupled to the bottom of one of the shelves  32  near the front edge of the shelf.  FIG. 3  also shows wiring harnesses  50  coupling the light fixtures  48  to the track  42 .  FIG. 3  also shows an end cap  52  covering the top end of the track and a wiring harness  54  which couples the track to the power supply. The present invention provides improvements to the electrical assemblies in the form of wiring harnesses such as  50  and  54  shown in  FIG. 3 . 
         [0039]    One such improved electrical assembly is shown in  FIGS. 4-6 . Visible in  FIG. 4  is a vertical support rail  20  which includes a plurality of slots  21  used to couple the shelves  32  to the vertical support rail. Also shown in  FIG. 4  are the upper and lower back panels  30  and  26  as well as a coupling member  27  used to join the edges of the back panels  26  and  30  together. Attached adjacent to the top back panel  30  and the vertical support  20  is a first track portion or section  41  of track  42 . Attached adjacent back panel  26  and, vertical support  20  is a second track portion or section  43  of track  42 . During assembly, the upper track portion  41  is secured to panel  30  and the lower track portion  43  is secured to panel  26 . However, this leaves a physical gap between the track portions  41  and  43  and no electrical connection between the conductors residing within these track portions. 
         [0040]    To close the gap and provide such an electrical connection, wiring harness  50  is provided. The wiring harness  50  includes a positive insulated conductor  52  and a negative insulated conductor  54  which together comprise a 2-wire cable  56 . Attached to opposite ends of cable  56  are connectors  58 . These connectors are designed to mate with the open ends of the track sections  41  and  43  such that the wiring harness provides an electrical connection between the negative conductors within track portions  41  and  43  and, an electrical connection between the positive conductors located within the track portions  41  and  43 . More specifically, and as better illustrated in  FIG. 6 , the track portions  41  and  43  include a pair of electrical conductors  60  and  61  located on opposite sides of a channel  62 . The channel  62 , as well as the two electrical conductors  60  and  61 , runs the length of the track sections  41  and  43 . The connectors  58  mate with the open ends of the track portions  41  and  43  as illustrated in  FIGS. 4 and 5 . 
         [0041]      FIGS. 7-17  provide greater details concerning the construction of the assembly  50  and the features of the connectors  58  which provide quick connect and quick disconnect functionality while at the same time ensuring that cross-wiring does not occur. 
         [0042]    As best shown in  FIGS. 14 ,  15  and  17 , the connectors  58  comprise a molded plastic housing  70  and a cover  72 . The connector housing comprises a base  74 . Extending upwardly from the base is a proximal wall  76 , a pair of sidewalls  78  and  80  and a distal wall  82 . Extending forward from the distal wall  82  is a tongue  84 . A chamber  86  is formed by the base  74  and the proximal, side and distal walls  76 - 82  of the connector housing  70 . The proximal wall  76  includes an opening  77  through which the cable  56  may pass. The sidewalls  78  and  80  include lock openings  79  and  81 . The distal wall includes an opening  83 . The tongue  84  is external to the distal wall  82  in a direction opposed to the chamber  86 . The tongue  84  includes an alignment rail  86  and non-conductive pins  90  and  92  projecting upwardly from the tongue  84 . 
         [0043]    As noted above, the cable  56  includes a positive conductor  52  and a negative conductor  54 . The opposed ends of positive conductor  52  are connected, such as by soldering, to flat conductor tabs  100  and the opposed ends of conductor  54  are connected, such as by soldering or the like, to flat conductor tabs  102 . Each flat conductor tab has a hole  104  extending through the tab. Strain reliefs  106  cover and support the connection between the conductors  52  and  54  and the conductor tabs  100  and  102 . 
         [0044]    As part of the assembly process, the ends of the cable  56  are inserted into the housings  70  of the connectors so that the cable passes through the opening  77  in the proximal wall  77  of the base  74 , the strain reliefs  106  at one end of the cable reside within the chamber  86  of the housing and the flat conductor tabs  100  and  102  extend through the opening  83  in the distal wall and the holes  104  in the connector tabs  100  and  102  mate with respective pins  90  an  92  on the tongue  84 . Further, the outside edge  108  of tab  100  and the outside edge  110  of tab  102  extend outwardly in opposite directions beyond the side edges of the tongue  84  when so assembled. When the flat conductor tabs  100  and  102  are over the pins  90  and  92  such that the pins  90  and  92  extend through the holes  104 , the alignment rail  88  extends between the inside edges of the tabs  100  and  102  to prevent them from coming in contact with each other and a short circuit being formed, 
         [0045]    The cover  72  of the connector housing  70  includes a chamber cover portion  120  and a tongue cover portion  122 . Projecting from the sides of the chamber cover portion  120  are locking tabs  124  which mate with the lock openings  79  and  81  of the connector housing  70 . Further, the tongue cover member  122  includes an alignment channel.  126  which mates with the alignment rail  88  such that the alignment rail  88 , alignment channel  126 , lock openings  79  and  81  and locking tabs  124  secure the cover  72  to the housing  70  to complete the assembly. 
         [0046]    When so assembled, the strain reliefs  106  are locked within the chamber  86  and the conductor tabs  100  and  102  are locked in place by the pins  90  and  92  between the tongue  84  and the tongue cover member  122 . 
         [0047]    Extending outwardly from one side of the tongue cover member  126  (or alternatively tongue  84 ) is an alignment guide  128 . This alignment guide ensures that the connector  58  is not inserted into the end of the track  42  upside down which could lead to a short circuit or cross-wiring. The ends of the track sections are made asymmetrical and cooperate with the alignment guide  128  to provide this advantage. 
         [0048]    As illustrated in  FIGS. 4-6  and  16 - 17 , two connectors  58  are attached at opposite ends of the cable  56  to complete the construction of the wiring harness. One of the connectors is attached to rail portion  41  and the other is attached to rail portion  43 . When so connected, independent electrical connections are made between the positive conductors  60  of the rail portions  41  and  43  via the positive conductor  52  and the positive conductor tabs  100  of the harness  50 . Likewise, an electrical connection is made between the negative conductors  61  of the track portions  41  and  43  via the negative conductor  54  and the negative conductor tabs  102  of the harness  50 . The alignment guides  128  of the connectors  58  prevent the connectors  58  from being inserted into either track portion  41  or track portion  43  upside down which would, of course, lead to cross-wiring in a short circuit. 
         [0049]    In many cases, friction between the elements associated with the tongue portions of the connectors  58  and the channels  62  of the track portions  41  and  43  will prevent inadvertent disconnection or dislodgement of the wiring harness  50  from the track portions. To provide an additional measure of security, each track portion includes a hole  130  extending through the back of the track near the end of the track portion. Likewise, each connector includes an arch-shaped tab  132  extending outwardly from the tongue cover member  122  which engages the hole  130  when the connector is joined to the end of the rail portion to provide further engagement. 
         [0050]    It should be clear from the foregoing the electrical assembly  50  provides a quick, easy and error-free method of creating a proper electrical connection between the track portions  41  and  43 . Further, when the shelving assembly  10  is disassembled such that the panel  30  is removed, the electrical assembly comprising harness  50  will disconnect from one or both of the track sections  41  or  43  automatically and without damage to the track or the harness. There is no need for a person disassembling the shelf to disconnect the harness before taking the back of the shelving unit apart. 
         [0051]    Connectors such as  58  may be used with other electrical assemblies to attach other items to the track.  42 . As shown in  FIG. 3 , one item typically coupled to the track is a power supply  44 . Power supplies often include a pin-type connector designed to be coupled to a barrel jack. As shown in  FIGS. 18 and 19 , a harness can easily be formed with such a barrel jack  140  at one end and connector  58  of the present invention at the opposite end, enabling the power supply  44  to be quickly and easily coupled to the track in an error-free manner. 
         [0052]    Other power supplies incorporate other types of connectors.  FIGS. 20 and 21  show a harness incorporating the connector  58  to the present invention at one end and an alternative power supply connector  142  at the opposite end. 
         [0053]    Sometimes it is desirable to attach a pair of electrical devices to a track or, alternatively, supply power from a single power supply to a plurality of tracks.  FIGS. 22 and 23  illustrate harnesses which incorporate the track connector  58  of the present invention with a pair of cables, one cable  56  attached at its opposite ends and to a female Molex connector and the other cable  57  attached at its opposite end to a male Molex connector.  FIGS. 18-23  are provided to demonstrate that the connector  58  of the present invention has multiple applications when forming harnesses and the opposite end of the cable can be joined to the identical connector or to any of a variety of alternative connectors, those shown in  FIGS. 18-23  merely illustrating some of the multitude of options which are available. 
         [0054]    From the foregoing, it will be appreciated that although specific examples have been described herein for purposes of illustration, various modifications may he made without deviating from the spirit and scope of this disclosure. By way of example, wiring harnesses may be formed using the connector of the present invention which includes one, two or even more cables with any of a number of different connectors attached to the opposite ends of the cables. Likewise, the harnesses may be colored to match the shelving with which they are used to hide them from view. Alternatively, the harnesses, connectors or cables may be color coded to meet the needs of a specific application. Likewise, various indicia may be provided on the connector of the present invention. Such indicia may be in the form of written labeling or ridges or the like formed in the connector housing  70  or connector cover  72 . Likewise, the materials used to form various components may vary depending on the particular application. For example, the gauge of the wire used in the cabling may be altered and the material used as conductive elements in the cable may be altered depending on the cost of raw materials. Examples of such conductive materials include aluminum or copper. The cable, of course, will be provided with a non-conductive sheath to prevent a short circuit from being created between the conductive elements and the shelving components which are typically made of metal. Likewise, the housing and cover of the connectors  58  can be made out of any of a variety of non-conductive plastics or other non-conductive materials. It is, therefore, intended that the foregoing detailed description be regarded as illustrative rather than limiting, and that it be understood that it is the following claims, including all equivalents, that are intended to identify the invention.