Abstract:
An electro-mechanical connection is provided for transmitting power to one or more light sources affixed to the shelves of a shelving system. The connection eliminates the need to run wires the entire distance from the light source to a source of power and enables efficient and accurate coupling of the components. This is achieved by provided a slim track strip extending the height of the shelving unit and a specially designed twist connector for tapping off wiring harnesses from the slim track at the level of individual shelves where the harness leads to shelf-mounted light sources.

Description:
CROSS-REFERENCED TO RELATED APPLICATIONS 
     Not applicable 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable 
     BACKGROUND OF THE INVENTION 
     I. Field of the Invention 
     The present invention relates generally to lighting for shelving systems and, more specifically, to electrical connectors for connecting low voltage light sources to low voltage electrical slim tracks associated with such shelving systems. 
     II. Related Art 
     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. 
     Many retail establishments employ overhead ambient light sources and shelving systems for holding merchandise which include a set of vertically arranged shelves which are relatively deep and opaque. This arrangement causes shadows to be cast upon items placed on the lower shelves of the set of shelves because the upper shelves block much of the light. 
     Various lighting and shelving systems have been employed to address this issue. However, such lighting systems often include long wires extending from each individual light source all the way back to a power source. The wires are often twist-tied to shelves and other components of the shelving system, but this is a laborious process and the result is unpleasing from an aesthetics standpoint. 
     SUMMARY OF THE INVENTION 
     The electro-mechanical connection comprises a low voltage electrical slim track, a twist lock connector and a harness. The slim track has an elongate slot defined by first and second lips, a first track conductor adjacent the first lip and extending along a first side of the slot and a second track conductor adjacent the second lip and extending along a second side of the slot. 
     The twist lock connector comprises a plastic connector housing having first and second ends, first and second support ribs located at the first end of the connector housing, an interior wall defining a central channel extending the entire length and open to the first and second ends, and a flange having first and second gaps. The twist lock connector further comprises a first mating member extending from the connector housing and having a first exterior shape and a first mating channel, and a second mating member extending from the connector housing and having a second exterior shape different than the first exterior shape and a second mating channel. The twist lock connector also has first and second locking tabs. The first locking tab extends across the first gap on the flange and is mounted, such as by an integrally formed living hinge, to the flange for movement between a locked position and an unlocked position. Likewise, the second locking tab extends across the second gap on the flange and is similarly mounted to the flange by a living hinge for movement between a locked position and an unlocked position. The twist lock connector further includes first and second connector contacts. Each of the first and second connector contacts has first and second legs extending perpendicular to each other. The first leg of the first connector contact is in engagement with the first support rib of the housing and the second leg of the first connector contact extends through the central channel of the housing and into the first mating channel of the first mating member. Likewise, the first leg of the second conductor contact is in engagement with the second support rib of the housing and the second leg of the second conductor contact extends through the central channel of the housing and into the second channel of the second mating member. The twist lock connector further comprises a contact plug cooperating with the interior wall defining the central channel of the housing to retain the first and second connector contacts in place. 
     When the locking tabs are in the unlocked position, the first legs of the first and second connector contacts are adapted to be inserted into the elongate slot of the low voltage electrical slim track and rotated to bring the first leg of the first connector contact into conductive engagement with the first track conductor and the first leg of the second connector contact into conductive engagement with the second track conductor. When the locking tabs are in the locked position the first legs of the first and second connector contacts cannot be rotated out of engagement with the track conductors. Also, the twist lock connector is held in place vertically along the track because the first legs of the connector contacts and the flange of the twist lock connector reside on opposite sides of the lips (and possibly also the track conductors) of the slim track and provide a pinching force. 
     The harness comprises a cable. At the one end of the cable is a first harness housing having a first end and a second end, a first port having a first interior shape corresponding to exterior shape of the first mating member of the twist lock connector and open to the first end, a second port having a second interior shape corresponding to exterior shape of the second mating member of the twist lock connector and open to the first end. The harness connector further comprises an electrical contact located in the first port of the first harness housing and coupled to a first conductor of the twist lock connector and an electrical contact located in the second port of the first harness housing and coupled to a second conductor of the twist lock connector. The harness connector is adapted to be joined to the twist lock connector by mating the first part with the first mating member and the second port with the second mating member to thereby provide a conductive engagement. A second end of the cable may be attached directly to a light source or to a second harness housing used to couple the harness to a light source such that the light source is powered from the track via the twist lock and harness. The second harness housing may be identical to the first harness housing. The design of the second harness housing may be modified to accommodate connection to any of a variety of light sources and the design of the second harness housing will, therefore, depend on the light source selected for use. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       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 in the several views refer to corresponding parts. 
         FIG. 1  is a perspective view of an electro-mechanical connection. 
         FIG. 2  is a top view of a portion of the electro-mechanical connection shown in  FIG. 1 . 
         FIG. 3  is a partial exploded view of the electro-mechanical connection shown in  FIG. 1 . 
         FIG. 4  is an exploded view of the twist lock connector of the electro-mechanical connection shown in  FIG. 1 . 
         FIG. 5  is a perspective view of the twist lock connector of the electro-mechanical connection shown in  FIG. 1 . 
         FIG. 6  is a second perspective view of the twist lye lock connector of the electro-mechanical connection shown in  FIG. 1 . 
         FIG. 7  is a side view of the twist lock connector; and 
         FIG. 7A  is a cross-section through line A-A in  FIG. 7 . 
         FIG. 8  is a perspective view showing a harness conductor comprising two identical harness housings. 
         FIG. 9  is a perspective view of a gondola-type shelf. 
         FIG. 10  is a perspective view of a harness suited for use with gondola-type shelving. 
     
    
    
     DETAILED DESCRIPTION 
     The description of the preferred embodiments 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 derivatives 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”, “join” 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. 
       FIG. 1  shows a novel electro-mechanical connection comprising a low voltage electrical slim track  10 , a twist lock connector  20  ( FIG. 3 ), a harness  70  and a light source  90 . The low voltage electrical slim track  10  comprises an elongated slot  12  defined by a first lip  14  and a second lip  16 . Extending along the length of the elongate slot  12  adjacent the first lip  14  is a first track conductor  15 . Extending along the elongate slot  12  adjacent the second lip  16  is a second track conductor  17 . The lips  14  and  16  and the conductors  15  and  17  extend substantially the entire length of the elongate slot  12 . 
     When the electro-mechanical connection  1  of the present invention is used in connection with shelving, such as retail shelving, the low voltage electrical slim track  10  can be attached to the back of the shelving so that it extends vertically from the bottom of the shelving to the top with the slot opening defined by the lips  14  and  16  facing the front of the shelving. Those skilled in the art will recognize that a power supply (not shown) will be coupled to the electrical slim track  10  for delivery of electrical power along the entire length of the first and second track conductors  15  and  17 . 
     The electro-mechanical connection  1  further includes a twist lock connector  20  ( FIG. 3 ). The twist lock connector is designed so that it can be coupled to the track  10  at any point along the elongate slot  12  and track conductors  15  and  17 . While one such twist lock connector  20  is shown in the drawings, the reader should appreciate that multiple twist lock connectors  20  can be attached to the track at various desired locations along the track. Each twist lock connector  20  includes a plastic connector housing  22  ( FIG. 4 ) having a first end  24  and a second end  26 . The connector housing surrounds a central channel, defined by an interior wall  28 , which extends between, and is open to, the first end  24  and second end  26  of the housing. 
     The plastic connector housing  22  also includes a flange  30  adjacent to the first end  24  of the housing  22 . The flange includes a first inset or gap  32  and a second inset or gap  34 . Projecting forward of the flange  30  is a cylindrical member  35  having a first support rib  36  and a second support rib  38  separated by a first rib divider  40  and a second rib divider  42 . 
     Extending from the second end  26  of connector housing  22  is a first mating member  44  having a first mating channel  45  and a second mating member  46  having a second mating channel  47 . The first and second mating members  44  and  46  are shown as having two different exterior, i.e., cross-sections. The first mating channel  45  and second mating channel  47  comprise generally rectangular bores that extend the entire length of the associated mating member and are in open communication with the central channel defined by interior wall  28  of the connector housing  22 . 
     Pivotally connected to the connector housing  22  of twist lock connector  20 , such as by integrally formed living hinges, is a pair of locking tabs  48  and  50 . First locking tab  48  extends across and is pivotally secured within the first gap  32  for pivotal movement between the first locked position and a second unlocked position. Likewise, the second locking tab  50  is positioned within the second gap  34  for similar pivotal movement between a first locked position and a second unlocked position. Pins, axles, or ears can be used instead of integrally formed living hinges to pivotally secure the locking tabs  48  and  50  within the respective gaps  32  and  34 . As shown in the drawings, a raised orientation note  49  is formed onto the first locking tab  48  and signifies the “up” position of the connector when the connector is joined to the electrical slim track  10 . 
     The twist lock connector  20  also includes a first connector contact  52  ( FIG. 4 ). Connector contact  52  has a first leg  54  and a second leg  56 . The two legs extend generally perpendicular to each other. The first leg  54  of the first connector contact  52  extends over and engages the first support rib  36  while the second leg  56  of the first connector contact extends through the central channel of the housing and into the first mating channel  45  of the first mating member  44 . Also shown is a second connector contact  58  which also has a first leg  60  and a second leg  62 . The first leg  60  of the second connector contact  58  engages the second support rib  38  while the second leg  62  extends through the central channel  28  of the housing and into the second mating channel  47  of the second mating member  46 . A contact plug  64  cooperates with a first rib divider  40  and a second rib divider  42  and also with the walls defining the first mating channel  45  and second mating channel  46  to provide appropriate spacing between the first and second connector contacts  52  and  58  to prevent a short circuit and to retain the connector contacts  52  and  58  in place, all as best seen in  FIG. 7A . 
     As illustrated in  FIGS. 1-3 , the twist lock connector is adapted to be joined to the electrical slim track  10 . To join the twist lock connector  20  to the electrical slim track  10 , the twist lock connector  20  is placed in the position shown in  FIG. 3  and the two locking tabs  48  and  50  are squeezed together toward the first and second mating members  44  and  46 . The twist lock connector  20  is then advanced toward the track until the flange  30  engages the lips  14  and  16  of the track. The twist lock connector  20  is then rotated about 90 degrees as illustrated in  FIG. 3  into the position shown in  FIGS. 1 and 2 . This causes the ends of the first legs  54  and  60  of the connector contacts  52  and  58  to engage and form an electrical connection with the track conductors  15  and  17 . 
     More specifically, the first legs  54  and  60  of connector contacts  52  and  58  reside on the inside of lips  14  and  16  of the track in electrical contact with the respective track conductors while the flange  30  resides on the outside of lips  14  and  16 . The tolerances are such that the flange  30  and first legs  54  and  60  provide a pinching force which retains the twist lock connector at the desired vertical location along the track  10 . Releasing the locking tabs  48  and  50  causes them to return to the locked position preventing rotation (and inadvertent release) of the twist lock connector  20  relative to the electrical slim track  10  until the locking tabs  48  and  50  are again squeezed toward each other. To prevent the twist lock connector  20  from being rotated in the wrong direction and thereby reduce the possibility of crossed electrical connections, indicia in the form of raised orientation  49  are provided. 
     As shown in  FIGS. 1 and 3 , the electro-mechanical connection  1  also includes a harness  70 . The harness  70  includes a cable containing at least two wires  81  and  83 . The wires  81  and  83  of the harness  70  may be coupled at one and to a first harness housing  71  and at the other end to a light source  90  (such as by soldering the ends of the wires  81  and  83  to the light source  90 ) as suggested by  FIG. 1 . Alternatively, a second harness housing  71  may be employed at the opposite ends of the wires  81  and  83  as shown in  FIG. 8  such that two harness housings  71  are provided. In this case, the second harness housing is used to connect the harness  70  to the light source  90 . 
     The first harness housing  71  has a first end  72  coupled to the cable and a second end  73 . The first harness housing  71  has, at the second end  73 , an opening to a first port  74  and an opening to a second port  78 . The ports  74  and  78  of the first harness housings  71  are sized to receive the first and second mating members  44  and  46  of the twist lock connector  20 . To ensure the electrical connections are properly made, the interior wall defining the first port  74  has the same shape as the exterior wall of the first mating member  44  and the first port  74  is sized to receive the first mating member  44 . Likewise, the interior wall defining the second port  78  of the harness housing  71  has a shape matching the exterior wall of the second mating member  46 . The second port  78  is designed to receive the second mating member  46 . The risk of an improper cross-connection between the twist lock connector  20  and first harness housing  71  is eliminated because the shapes of the two ports  74  and  78  differ and because the shapes of the mating members  44  and  46  also differ. 
     To provide electrical connectivity, the first harness housing  71  contains a third electrical, contact  80  ( FIG. 1 ) located within the first port  74  and a fourth electrical contact  82  located within the second port  78 . As such, when the first harness housing  71  is mated with the twist lock connector  20 , the third electrical contact  80  engages the first connector contact  52  and the fourth electrical contact  82  engages the second connector contact  56 . 
     As best shown in  FIG. 1 , wire  81  extends from the third electrical contact  80  of harness  70  and a wire  83  extends from the fourth electrical contact  82  of the harness  70 . These wires  81  and  83  electrically couple a light source  90  to the harness  70 . The light source  90  can be of any standard type including one or more incandescent bulbs, one or more fluorescent tubes, but in low voltage applications LEDs have proven to be highly advantageous. In  FIG. 1 , the light source is shown as including four LEDs  92 ,  94 ,  96  and  98 . These LEDs may be single color LEDs or multi-colored LEDs. Likewise, when single colored LEDs are used, the individual LEDs  92 ,  94 ,  96  and  98  may be of different colors. 
     Rather than making the direct connection between the wires  81  and  83  and the light source  90  shown in  FIG. 1 , certain benefits may result from proving a second harness housing  71  at the second ends of the wires  81  and  83  as shown in  FIG. 8 . The two harness housings  71  may have identical configurations. Alternatively, one of the harness housings  71  may be adapted for use with a particular style of twist lock connector  20  and the other harness housing  71  adapted for use with a particular style of light fixture  90 . Further, raised indicia, such as  75 , may be provided on the harness housings  71  to help a user align and attach the harness housings  71  to light source  90  and twist lock connector  20 . 
     Based upon the foregoing description, one of ordinary skill in the art will appreciate that the electro-mechanical connection  1  provides a simple, clean, neat, tidy, useful and attractive mechanism for lighting retail shelving or the like. More importantly, the electrical connection described above eliminates the need for wires to dangle or to be bundled or to run all the way from a light source to a power supply. Instead, a single power supply powers the track  10 . Likewise, the electro-mechanical connection  1  permits one or more light sources  90  to be attached to each shelf of a shelving unit, allowing the height of the individual shelves of the shelving unit to be adjusted and for a short, direct connection to be made between the light source and the track at whatever height the individual shelves are placed. 
     While the harness housings  71  frictionally engage the conductors leading to the light sources as well as the twist lock connectors  20  to which they are attached to ensure a stable electrical connection, there is no mechanism firmly locking the harness housings  71  in place. Thus, should a user remove a shelf without first disconnecting the harness connector  70  from the light source or twist lock connector  20 , the harness connector  70  will automatically disconnect from the twist lock connector  20  and/or light source when the shelf is removed without damaging any of the components. To add strength and durability, a strain relief  85  may be coupled between the cable and the harness housings  71  of the harness connector  70  as also illustrated in  FIG. 8 . 
     The components of the electro-mechanical connection described above are well-suited for lighting a gondola-type shelving system. The track  10  can be mounted to the back and extend vertically. Twist lock connectors  20  can be positioned in the track  10  at approximately the same height as the shelves. See, for example, shelf  110  in  FIG. 9 , and the light source  90  can be fastened to the bottom of the shelf at its front edge. The harness  70  can then be attached to the twist lock connector  20  and light source  90  with the wires  81  and  83  being out of sight and running from the front to the back of the shelf  110  beneath the shelf  110 . 
       FIG. 10  shows a modification to the harness  70  which provides for even a neater and cleaner installation. As shown in  FIG. 10 , the harness  70  has a pair of harness housings  71  and  73 . Harness housings  71  form a connection with a twist lock connector  20  and the other harness housing  73  forms a connection with the light source  90  as described above. A cable, comprising wires  81  and  83 , extends between and electrically couples the two harness housings  71  and  73 . The harness  70  further includes a wire tray  100 . The wire tray  100  has a U-shape cross section and is elongate extending substantially the length of the wires  81  and  83 . The wire tray  100  thus includes a channel  102  extending its entire length in which the wires  81  and  83  reside with only a small portion of the wires extending past the two ends of the wire tray  100 . The wire tray  100  also has a plurality of retainers  104  which can be bent over the top of the channel  102  after the wires  81  and  83  have been placed in the channel  102  to secure the wires  81  and  83  in the channel  102 . The wire tray  100  also includes at least one coupling member  106  to secure the wire tray  100  to an undersurface of a shelf such as shelf  110 . 
     The style of coupling member  106  will vary depending upon the nature of the shelf. The coupling member  106  may be in the form of a magnet, screw, adhesive, clip, hook or the like.  FIG. 10  shows two coupling members  106  which are suited for use with a gondola shelf  110  of the type shown in  FIG. 9 . It includes rows of holes  112  extending along the front and back. As shown in  FIG. 10 , the coupling members  106  are upstanding hooks integrally formed with and extending upwardly from the wire tray  100 . One of the hooks  106  mates with a hole  112  near the front of the shelf  110  while the other hook  106  mates with a hole  112  near the back of the shelf  110  to secure the wire tray and harness  70  to the shelf  110 . The length of the hooks  106  will depend on the height of any shelf framing members (not shown) on the underside of the shelf  110  which must be crossed by the wire track  100 . 
     When the wire harness  70  including the wire tray  100  of  FIG. 10  is employed, prior to mounting of the shelf  110  to a shelving system, the light source  90  may be mounted to the underside and proximate the front of shelf  110 , the wire tray may also be mounted to the shelf  110  by coupling the hooks  106  of wire tray  100  with holes  112  of the shelf, and the connection between the light source  90  and harness housing  73  of the harness  70  may be made. Likewise, the twist lock connector  20  may be coupled to the track  10  before the shelf  110  is installed so that after installation of the shelf  110 , the only connection remaining to be made is between the other harness housing  71  and the twist lock connector  20 . This makes installation extremely easy. The installer is not required to make all of the electrical connections and route wires after installation of the shelves which can be awkward and difficult. Further, because there are no locks used to couple the twist lock connector  20  and harness housing  71  together, the connection between the twist lock connector  20  and harness housing  71  simply pulls apart when a shelf  110  is removed from the shelving system. 
     From the foregoing, it will also be appreciated that although the specific examples have been described herein for purposes of illustration, various modifications may be made without deviating from the spirit or scope of this disclosure. It is therefore intended that the foregoing detailed description be regarded as illustrative rather than limiting and that the following claims, including all equivalents, are intended to define the invention.