Patent Publication Number: US-8535070-B2

Title: Connector for electrified ceiling grid

Description:
FIELD OF THE INVENTION 
     The present invention is directed to connectors, and, more particularly, to connectors for making low voltage direct current electrical connections between conductive elements of an electrified grid. 
     BACKGROUND OF THE INVENTION 
     The electrical grid connecting America&#39;s power plants, transmission lines and substations to homes, businesses and factories operate almost entirely within the realm of high voltage alternating current (AC). Yet, an increasing fraction of devices found in those buildings actually operate on low voltage direct current (DC). Those devices include, but are not limited to, digital displays, remote controls, touch-sensitive controls, transmitters, receivers, timers, light emitting diodes (LEDs), audio amplifiers, microprocessors, other digital electronics and virtually all products utilizing rechargeable or disposable batteries. 
     Installation of devices utilizing low voltage DC has been typically limited to locations in which a pair of wires is routed from the voltage source. Increased versatility in placement and powering of low voltage DC products is desirable. Specifically, there is an increasing desire to have electrical functionality, such as power and signal transmission, in the interior building environment, and specifically in the ceiling environment, without the drawbacks of existing systems. 
     Commercial building spaces such as offices, laboratories, light manufacturing facilities, health facilities, meeting and banquet hall facilities, educational facilities, common areas in hotels, apartments, retirement homes, retail stores, restaurants and the like are commonly constructed with suspended ceilings. These suspended ceiling installations are ubiquitous, owing to their many recognized benefits. Such ceilings ordinarily comprise a rectangular open grid suspended by wire from a superstructure and tile or panels carried by the grid and enclosing the open spaces between the grid elements. 
     Many relatively low power devices are now supported on such ceilings and newer electronic devices and appliances are continuously being developed and adopted for mounting on ceilings. The ceiling structure, of course, typically overlies the entire floor space of an occupiable area. This allows the ceiling to support electronic devices where they are needed in the occupied space. Buildings are becoming more intelligent in energy management of space conditioning, lighting, noise control, security, and other applications. The appliances that provide these features including sensors, actuators, transducers, speakers, cameras, recorders, in general, all utilize low voltage DC power. 
     A conventional grid framework, such as one used in a surface covering system, includes main grid elements intersected by cross grid elements therebetween. The main and cross elements form a grid of polygonal openings into which components such as panels, light fixtures, speakers, motion detectors and the like can be inserted and supported. Known systems that provide electrification to devices, such as lighting components, in conventional framework systems utilize a means of routing discrete wires or cables, principally on an “as needed” point-to-point basis via conduits, cable trays and electrical junctions located in the space behind the grid framework. 
     These known systems suffer from the drawback that the network of wires required occupy the limited space behind the grid framework and are difficult to service or reconfigure. Moreover, the techniques currently used are limited in that the electricity that is provided is not reasonably accessible from all directions relative to the framework plane. For example, electricity can be easily accessed from a ceiling plenum, but not from areas within or below the plane of the grid framework of a suspended ceiling system. Further, the electrical power levels that are typically available are not safe to work with for those not trained, licensed and/or certified. 
     In known systems utilizing track systems, the connecting devices have terminals that provide electrical connections to conductors provided in a track. These tracks also typically require wiring and mechanical support from the area behind the grid framework. In addition, existing track systems are typically viewable from the room space and are aesthetically undesirable. Further still, known track systems typically utilize higher voltage AC power and connect to AC powered devices, requiring specialized installation and maintenance. 
     In an effort to overcome some of the problems with prior systems, internal bus bars have been positioned in the ceiling grid. One such system is described in the documents related to the Emerge Alliance. Such systems provide electrical power through two parallel bus bars embedded with the support rails of a suspended ceiling. Electrical connectors are mated with the bus bars to supply power to various low voltage devices. However, these connectors are often difficult to install or they are expensive and complicated to manufacture and assembly. 
     What is needed are connectors which can be terminated to a grid framework system that provides low voltage DC power connections that can be safely utilized from all angles relative the plane of the grid framework. The present invention accomplishes this need and provides additional advantages. 
     SUMMARY OF THE INVENTION 
     An exemplary embodiment is directed to a connector for installation on a ceiling grid having conductors therein. The connector comprising has a housing, with contact arms mounted in the housing and movable between a first position in which contact portions of the contact arms are not placed in electrical engagement with the conductors and a second position in which the contact portion are place in electrical engagement with the conductors when the connector is mated with the ceiling grid. Mounting members are also positioned in the housing and are movable between a first position in which grid mounting sections of the mounting members are not placed in mechanical engagement with the ceiling grid and a second position in which the grid mounting sections are placed in mechanical engagement with the ceiling grid to provide a mechanical connection between the ceiling grid and the connector. A cam member is provided in the housing. The cam member is movable between a first position, in which the cam member allows the contact arms to be in their first position and the mounting members to be in their first position, and a second position, in which the cam member causes the contact arms and mounting members to be biased to their respective second positions. 
     An exemplary embodiment is also directed to a connector for installation on a ceiling grid having conductors therein. The connector has housing. Contact arms are mounted in the housing, with the contact arms having contact portions. Mounting members are mounted in the housing, with the mounting members having grid mounting sections. A cam member is provided in the housing, with the cam member being movable between a first position and a second position. As the cam member is moved from the first position to the second position, the cam member biases the contact portions of the contact arms into electrical engagement with the conductors of the ceiling grid and biases the grid mounting sections of the mounting members mechanical engagement with the ceiling grid to provide a mechanical connection between the ceiling grid and the connector. 
     An exemplary embodiment is also directed to a connector for installation on a ceiling grid having conductors therein. The connector has a housing. Contact arms are mounted in the housing, with the contact arms having contact portions. Mounting members are mounted in the housing, with the mounting members having grid mounting sections. A cam member is provided in the housing, with the cam member being movable between a first position and a second position. The cam member is a linear member which extends in a direction which is essentially parallel to a longitudinal axis of the connector. As the cam member is moved from the first position to the second position, the cam member biases the contact portions of the contact arms into electrical engagement with the conductors of the ceiling grid and biases the grid mounting sections of the mounting members mechanical engagement with the ceiling grid to provide a mechanical connection between the ceiling grid and the connector. 
     Other features and advantages of the present invention will be apparent from the following more detailed description of the preferred embodiment, taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a perspective view of a room space having an electrified ceiling according into which a connector can be inserted and electrically engaged. 
         FIG. 2  shows a perspective view of a section of an exemplary grid member which can be used in the electrified ceiling of  FIG. 1 . 
         FIG. 3  shows a perspective view of an exemplary connector according to an exemplary embodiment. 
         FIG. 4  shows a front elevational view of the exemplary connector of  FIG. 3 . 
         FIG. 5  shows a top view of the exemplary connector of  FIG. 3 . 
         FIG. 6  shows a perspective view of the exemplary connector as the connector is fully inserted into the exemplary grid member. 
         FIG. 7  shows an exploded view of the exemplary connector. 
     
    
    
     Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. 
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention will be described more fully hereinafter with reference to the accompanying drawings, in which illustrative embodiments of the invention are shown. In the drawings, the relative sizes of regions or features may be exaggerated for clarity. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. 
     It will be understood that spatially relative terms, such as “top”, “upper”, “lower” and the like, may be used herein for ease of description to describe one element&#39;s or feature&#39;s relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “over” other elements or features would then be oriented “under” the other elements or features. Thus, the exemplary term “over” can encompass both an orientation of over and under. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly. 
     The present invention is directed to connectors for use with an electrified framework or ceiling grid. For illustrative purposes,  FIG. 1  shows a room space  10  having a ceiling  12  supported by a ceiling grid framework  14 . However, any system having a grid framework, including floors and wall, can utilize the technology of the invention. The ceiling  12  may include decorative tiles, acoustical tiles, insulative tiles, lights, heating ventilation and air conditioning (HVAC) vents, other ceiling elements or covers and combinations thereof. Power for low voltage devices  16  attached to or suspended from the ceiling  12  or framework  14  is provided by the conductive material placed upon the ceiling grid framework  14 . Low voltage devices  16 , such as, but not limited to, light emitting diode (LED) lights, speakers, smoke or carbon monoxide detectors, wireless access points, still or video cameras, or other low voltage devices, may be utilized with the electrified ceiling. 
     In the exemplary embodiment shown, conductive material is disposed on a surface of at least one of the plurality of grid members. In the exemplary embodiment shown in  FIG. 2 , first and second conductive strips  18  and  20  are disposed on a grid element  22  of the grid framework  14 . The conductive strips  18  and  20  have opposite polarity, i.e. one is positive and one is negative. The conductors  18 ,  20  are housed inside the lower box  24  of the grid element  22 . More specifically, in the exemplary embodiment shown, the conventional lower box  24  configuration typically has a base wall  26 , a pair of side walls  28  and a pair of flanges  30  that define a slot  32  therebetween. Conductors  18 ,  20  which are positioned on respective surfaces of the pair of sidewalls  28 . 
     One or more connectors  100  are provided to electrically connect the devices  16  to the grid elements  22  of the grid framework  14 . For example, a connector assembly  100  provides a low voltage electrical connection between the conductors  18 ,  20  on the grid framework  14  and a device  16  such as a light. 
     As shown in  FIGS. 3 through 7 , an exemplary connector assembly  100  for making a low voltage electrical connection between one or more devices  16  and conductors  18 ,  20  housed inside the lower box  24  of a grid element  22  is provided. The connector assembly  100  provides the electrical interface required and the flexibility of attaching the connector assembly  100  to the box  24  of a respective grid element  22  at any position along the length of the grid box  24 . In addition, the connector assembly  100  provides a robust mechanical connection with the grid element  22  and an electrical connection between the conductors  18 ,  20  and various devices  16 . 
     Referring to  FIG. 7 , the exemplary connector assembly  100  includes a connector housing  102  comprising two halves  104  and  106 . The connector halves  104 ,  106  are essentially identical, with connector half  104  being turned  180  degrees relative to connector half  106 . Therefore, for ease of explanation only connector half  104  will be described in detail. However, as the connector halves  104 ,  106  are identical, the detailed description of connection half  104  is equally applicable for connector half  106 . 
     Each housing is molded from plastic or other material having the strength and electrically insulative properties required. Connector half  104  has a top surface  110  which is configured to about against or be positioned proximate a respective flange  30  of the grid element  22 , as will be more fully described. The top surface  110  has a contact projection  112  which extends therefrom. In the exemplary embodiment shown, the contact projection  112  is positioned at the midpoint of the longitudinal axis of the top surface  110 . Openings  114  extend through the top surface  110 . In the exemplary embodiment shown, the openings  114  are positioned proximate the ends of the top surface  110  and are spaced equally from the contact projection  112 . Other positioning of the contact projections  112  and openings  114  can be used without departing from the scope of the invention. 
     A contact  120  is secured in each contact half  104 ,  106 . As best shown in  FIG. 7 , each contact  120  has a mounting portion  122  which has an opening  124  extending therethrough. First contact arms  126  extend from the mounting portion  122 . The first contact arms  126  are pressed into respective cavities in the housing half  104 ,  106  providing proper location and attachment to housing half  104 ,  106 . A second contact arm  128  extends from the mounting portion  122 . The second contact arm  128  has a contact portion  130  which is positioned proximate the contact projection  112 . The second contact arm  128  and the contact portion  130  are configured to have resilient characteristics. 
     Mounting hardware  132 ,  134 ,  136  extends through the opening  124  to mount the contact  120  to the housing half  104 ,  106 . Nut  136  is positioned in a recess  138  to provide the required retention of the nut  136  relative to the housing half. This configuration captures the nut  136  in a recess  138 , whereby, if the connector  100  must be opened in the field, the mounting hardware  132 ,  134 , nut  136 , and contact  120  will not fall out. 
     A device mounting hardware  142 , which in the exemplary embodiment is in the form of a hex nut with threads, is mounted in the housing  102 . Recesses  144  in each half  104 ,  106  maintain the mounting hardware  142  in position. A strain relief plate  146  is provided proximate the mounting hardware  142  so wires may be inserted through the strain relief plate  146  to provide proper strain relief In one exemplary embodiment, two wires (not shown) may be attached between the mounting hardware  132  and  134  and routed through the strain relief plate  146  and through the mounting hardware  142  to a respective external low voltage device  16 . 
     Mounting members  150  are positioned in mounting areas  151  of the housing  102 . Each mounting member  150  has a grid mounting section  152 , a connector mounting section  154 , a cam engagement section  156 , and a spring arm  157 . 
     Each mounting section  154  is mounted in the housing with section  152  extending through respective opening  114  of housing  102 . The mounting sections  154  cooperate with ribs on the walls of the mounting areas  151  of the housing to limit the movement of the mounting members  150 . The grid mounting sections  152  have spaced projections  153  which cooperate with the top surface of the flanges  30  to better maintain the mounting sections  254  is cooperation with the flanges  30 , as will be more fully described. 
     A cam member  170  is provided in the housing  102 . In the exemplary embodiment shown, the cam member  170  extends is a linear member which extends in a direction parallel to the longitudinal axis of the housing  102 . The cam member  170  extends through openings  172  provided at either end of the housing  102 . The cam member  170  has camming surfaces  174  positioned on opposed side surface thereof Multiple camming surfaces  174  are provided on each side surface. In the exemplary embodiment, the camming surfaces  174  are projections which have a sloped surface, but various other configurations may be used. Operator engagement areas  176  are provided proximate the ends of the cam member  170 . Other configurations of the cam member  170  may be used without departing from the scope of the invention. 
     When installing the connector assembly  100  on a respective grid element  22 , the connector assembly  100  is moved toward the grid element  22 . As this occurs, the longitudinal axis of the assembly  100  is positioned essentially parallel to the longitudinal axis of the box  24  of the grid element  22 . As assembly  100  is moved toward grid element  22 , projection  112  and the contact portions  130  of the contacts  120  are inserted between flanges  30  into slot  32  of box  24 . Grid mounting sections  152  of mounting members  150  are also inserted between flanges  30  into slot  32  of box  24 . Insertion continues until the top surface  110  of the connector assembly  100  is in contiguous relation with the pair of flanges  30  of the box  24  which define the slot, such that the projection  112 , contacts  120  and mounting members  150  are properly positioned in the slot  32 . Other methods of insuring proper position of the projection  112 , contacts  120  and mounting members  150  may be used, such as, but not limited to, the top of the projection  112  engaging the base wall  26 . 
     With the assembly  100  properly inserted, an operator engages a respective operator engagement area  176 , causing the cam member  170  to be moved from a first position, in which the camming surfaces  174  do not engage the cam engagement sections  156  of the mounting members  150  or the contact arms  128  of the contacts  120 , to a second position, in which the camming surfaces  174  do engage the cam engagement sections  156  of the mounting members  150  and the contact arms  128  of the contacts  120 . As this movement from the first position to the second position occurs, the camming surfaces  174  engage the cam engagement sections  156  and the contact arms  128 , causing the sections  156  and arms to be biased outward in a direction toward the sidewalls  28  of the grid element  22 . 
     With the cam member  170  in the second position, the contact portions  130  of the contact arms  128 , which extend from the sides of the projection  112 , engage the conductors  18 ,  20  of the box  24 . As the contact arms  128  are resiliently deformable, the contact arms  128  of the contacts  120  will provide sufficient force to maintain a positive electrical connection between the conductors  18 ,  20  and the contact portions  130 . The resiliency of the contact arms  128  also allows the contact arms  128  and contact portions  130  to compensate for any irregularities in the conductors  18 ,  20 . In addition, the engagement sections  152  are biased outward to cooperate or engage with the flanges  30  to prevent the withdraw of the engagement sections  152  from the slot  32 , thereby providing a mechanical interface to maintain the assembly  100  in position relative to the grid element  22 . In the exemplary embodiment shown, the projections  153  are configured to be positioned proximate to or in engagement with the upper surfaces of the flanges  30  to provide a secure mechanical connection. 
     With the assembly  100  properly mounted to the grid element  22 , a low voltage electrical device may be mounted to the assembly  100  at mounting hardware  142 , thereby establishing an electrical connection between the conductors  18 ,  20  and the low voltage device by means of contact  120 , contact plate and mounting hardware  142 . The cooperation of the engagement sections  152  of members  150  with the grid element  22  provide sufficient mechanical support to support the weight of and to allow the low voltage device to hang from the assembly  100  and grid element  22 . 
     The assembly  100  is designed to hold a low voltage electrical device fixture and carry low voltage current thereto. In alternate exemplary embodiments, a conventional threaded component can be attached at the bottom of the housing  102  to hold a fixture such as a camera or lighting device. In addition, the housing  102  may include miscellaneous conventional fixture mounting hardware such as strain reliefs, nipples, etc. for attaching the low voltage electrical device, such as a pendant light, to the assembly  100 . In other exemplary embodiments, the low voltage electrical device may have wires which must be electrically connected to wires or contact pads of the assembly  100 . In such applications the wires may be inserted through the mounting hardware  142  and through the strain relief plate  146  to provide proper strain relief The ends of the wires may then be attached by placing them under and tightening screws or using other conventional means. The low voltage electrical device wires are then threaded through the fixture mounting hardware. 
     If the device is no longer needed, the device may be removed from the assembly  100 . The assembly  100  may then be removed from the grid element  22 . Alternatively, the assembly  100  may be removed from the grid element with the device still attached. In order to remove the assembly  100 , the cam member  170  is moved from the second position back to the first position. As this occurs, the contacts  120  and the mounting members  150  are allowed to return to their initial or unbiased positions, thereby causing the engagement sections  152  and contact portions  130  to move away from the sidewalls  28  of the grid element  22  and to disengage from the flanges  30 . Contact portions  130  return to their unbiased position due to their resilient characteristics, while engagement sections return to their initial position due to the forces exerted by spring members  157 . This allows for the withdraw of the engagement sections  152  and the contact portions  130  from the slot  32 , insuring that the assembly  110  can be both electrically and mechanically removed from the grid element  22 . 
     There are various advantages associated with the type of assembly described herein and represented by the exemplary embodiment of assembly  100 . Installation of the assembly onto the grid is intuitive and can be accomplished by trained installers and consumers alike. In addition, as the installation and removal of the connector does not damage the connector or the grid, the connector may be used over many cycles and for various devices. 
     As the projection and contacts are used to provide the electrical connection, the contacts can be configured to optimize the electrical connection to the conductors of the grid element. This allows the contacts to compensate for tolerances associated with the grid box. Once inserted into the grid element, the contacts are concealed and protected from damage. 
     With the engagement sections properly cammed into position, the engagement sections provide the mechanical connection required to maintain the assembly and device connected thereto in position. This allows the mechanical load on the contacts to be minimized, thereby allowing less material to be used for the contacts. 
     While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.