Abstract:
An electrical assembly including a plurality of electrical modules, each of the plurality of electrical modules being sequentially electrically connected to at least one other of the plurality of electrical modules. Each of the plurality of electrical modules including a coding circuit, each of the coding circuits interacting to identify a number of the plurality of electrical modules that are sequentially electrically connected.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This is a non-provisional application based upon U.S. provisional patent application Ser. No. 60/371,467, entitled “NEXT CONNECT”, filed Apr. 10, 2002. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an electrical distribution system, and, more particularly, to an electrical distribution system, which limits the activation of more than a predetermined number of electrical receptacles. 
     2. Description of the Related Art 
     Electrical wiring codes limit the number of receptacles which can be sequentially connected. It is common for an electrical power source to be routed to an electrical receptacle and power then routed from that electrical receptacle to a subsequent electrical receptacle and this is continued for several electrical receptacles. While there is no physical limitation in wiring in this manner, there are electrical considerations such as contact resistance that may preclude the subsequent connection of electrical receptacles ad infinitum. An electrician can circumvent the electrical code by wiring too many receptacles in a sequential manner. 
     A method to prevent the connection of too many electrical receptacles is to key cables and connectors on electrical receptacles to thereby preclude the attachment of too many electrical receptacles in a single circuit. A disadvantage of this method is that numerous unique cables and receptacle connections must be made. This reduces flexibility and increases the amount of inventory items that need to be stocked. 
     What is needed in the art is a system that will limit the number of electrical receptacles in a single power circuit without relying on unique keyed connector cable systems. 
     SUMMARY OF THE INVENTION 
     The present invention provides an electrical power distribution assembly for use in a modular wall panel system. 
     The invention comprises, in one form thereof, an electrical assembly including a plurality of electrical modules, each of the plurality of electrical modules being sequentially electrically connected to at least one other of the plurality of electrical modules. Each of the plurality of electrical modules including a coding circuit, each of the coding circuits interacting to identify a number of the plurality of electrical modules that are sequentially electrically connected. 
     The present invention advantageously allows an installer to connect electrical receptacles in a sequential manner. 
     Another advantage is that only one type of interconnecting cable is necessary. 
     A further advantage of the present invention is that each of the receptacles can be identical. 
     A still further advantage of the present invention is that if more than a predetermined number of electrical receptacles are connected, the receptacles are disconnected from electrical power. 
     Yet another advantage of the present invention is that compliance with the electrical code is automatic. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawings, wherein: 
         FIG. 1  is a perspective view of an embodiment of a modular wall panel system including a power distribution system having electrical receptacles of the present invention; 
         FIG. 2  is a block diagram of the power distribution assembly of the modular wall panel system of  FIG. 1 ; and 
         FIG. 3  is a schematic diagram of a circuit in the power distribution system of  FIGS. 1 and 2 . 
     
    
    
     Corresponding reference characters indicate corresponding parts throughout the several views. The exemplification set out herein illustrates one preferred embodiment of the invention, in one form, and such exemplification is not to be construed as limiting the scope of the invention in any manner. 
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the drawings, and more particularly to  FIG. 1 , there is shown a modular wall panel system  10  including a modular wall panel  12 , a raceway  14  and next connect receptacle assemblies  16 . Modular wall panel system  10  is utilized in a modem office space as partitioning walls in an open floor plan environment. 
     Now, additionally referring to  FIGS. 2 and 3 , power distribution system  18 , which is enclosed in raceway  14  is shown. Power distribution system  18  includes receptacle assemblies  16 , cable assemblies  20  and circuit assembly  22 . Cable assemblies  20  interconnect receptacle assemblies  16  with each other and a first receptacle assembly  16  to circuit assembly  22 . 
     Receptacle assemblies  16  are electrical modules that include a line conductor  24 , a neutral conductor  26 , a ground conductor  28 , a signal line  30 , a signal line return  32 , a circuit coding element  34 , a cover plate  36 , a neutral socket  38 , a power socket  40  and a ground socket  42 . Conductors  24 ,  26  and  28 , as well as signal line  30  and return  32  are electrically connected to cable assembly  20 . Further, line conductor  24  is electrically connected to power socket  40 , supplying electrical power from line conductor  24  to power socket  40 . In a like manner, neutral conductor  26  is electrically connected to neutral socket  38 , thereby providing a return path for electrical power that is conveyed to power socket  40 . Also in a like manner, ground conductor  28  is connected to ground socket  42 . Circuit coding element  34  is electrically connected across signal line  30  and signal line return  32  to thereby provide information to circuit assembly  22 . Circuit assembly  22  uses the information to determine the number of receptacle assemblies  16  sequentially connected to circuit assembly  22 . Circuit coding element  34  is exemplified in the present invention as a resistor  34 . Resistors  34 , in each of the receptacle assemblies  16 , are effectively connected in parallel to thereby alter the resistance between signal line  30  and signal line return  32 , thereby providing information to circuit assembly  22  as to the number of circuit coding elements  34  and consequently the number of receptacle assemblies  16  connected sequentially thereto. Even though resistor  34  has been shown in receptacle assembly  16 , other passive components or active components may be used to provide information by way of signal line  30  to circuit assembly  22 . 
     Cable assembly  20  includes cable  44  and connector  46 . Cable  44  has multiple conductors to accommodate the conveyance of electrical power and at least one signal. Connectors  46  are identical and connect with either end of receptacle assembly  16  or to circuit assembly  22 . Cable assembly  20  is utilized to connect circuit assembly  22  to a receptacle assembly  16  as well as to interconnect sequential receptacle assemblies  16 . Advantageously, cable assemblies  20  are identical and interchangeable, thereby reducing a need to inventory multiple cable configurations. 
     Plug  48  is connected to and provides electrical power to conductors  50  that pass the electrical power on to circuit assembly  22 . Circuit assembly  22 , also known as a control assembly  22 , includes a line conductor  52 , a neutral conductor  54 , a ground conductor  56 , and a circuit board assembly  58 . Line, neutral and ground electrical connections are respectively electrically connected to conductors  50  to provide power to circuit assembly  22 . Circuit board assembly  58  includes a transformer  60 , a rectification circuit  62 , a voltage regulator  64 , a capacitor  66 , a reference resistor  68 , a voltage reference zener diode  70 , a reference ground  72 , an operational amplifier  74 , a transistor  76 , a relay  78  and a connector assembly  80 . Connector assembly  80  interacts with, and is connected to, switched line conductor  82 , switched neutral conductor  84  and signal line  86 . 
     Electrical power is supplied to circuit assembly  22  by way of conductors  52  and  54 . Transformer  60  is connected across line conductor  52  and neutral conductor  54  to provide electrical power to the sensing circuit contained on circuit board assembly  58 . Incoming electrical power is transformed by transformer  60  to a lower voltage, which is then rectified by rectification circuit  62 . Voltage regulator  64  takes the rectified power and regulates the output to a specific DC level. Capacitor  66  substantially removes AC ripple from the DC voltage line. The voltage therefrom is supplied to operational amplifier  74  and transistor  76 . DC Voltage is also supplied to reference resistor  68 . Signal line  86  is connected to one input of operational amplifier  74 . The voltage on signal line  86  is the result of the voltage divided across resistor  86  that is in series with resistors  34  that are connected in parallel with each other. To another input of operational amplifier  74  there is connected zener reference diode  70 , which establishes a voltage reference for operational amplifier  74 . Operational amplifier  74 , is operating as a comparator  74  in that comparator  74  is comparing the voltage received from signal line  86  to the voltage reference of zener diode  70 . As long as the voltage present on signal line  86  exceeds the voltage from reference zener diode  70 , operational amplifier  74  has a positive voltage output which supplies current to and drives transistor  76 . Transistor  76  has a collector connected to the voltage output of regulator  64 . The base of transistor  76  is connected to the output of operational amplifier  74 . When operational amplifier  74  has a positive output and is driving the base of transistor  76 , current is conducted through the collector and out the emitter of transistor  76 , thereby driving a coil in relay  78 . When the coil in relay  78  is energized, the normally open contacts, to which switched line conductor  82  and switched neutral conductor  84  are connected to conductors  82  and  84 , are closed thereby electrically connecting line  52  to line  82  and neutral  54  to neutral  84 . 
     The operation of power distribution system  18  is such that as additional receptacle assemblies  16  are sequentially connected, resistors  34  are added in parallel with each other thereby altering the voltage on signal line  86 . As the voltage on signal line  86  is decreased to a point that it is less than the voltage from reference zener diode  70 , then operation amplifier  74  goes to a low state causing transistor  76  to no longer conduct current therethrough. This then de-energizes the coil in relay  78  causing normally open contacts to return to an open position. This then deactivates all electrical receptacles  16  until the number of electrical receptacles  16 , connected sequentially in power distribution system  18 , is reduced to be equal to or less than a predetermined number. The predetermined number exemplified in the present invention is eight, therefore by adding a ninth electrical receptacle  16  to power distribution system  18  will cause circuit assembly  22  to deactivate all electrical receptacles  16  connected thereto. This advantageously, automatically prevents an installer from violating an electrical wiring code. 
     Connector  80  of circuit assembly  22  connects to connector  46  of a cable assembly  20 . Signal line  86  of circuit assembly  22  is electrically connected to signal line  30  in each of receptacle assemblies  16 . Signal line return  32  may be connected to either ground line  56  or a separate line provided by way of connector  80 . 
     Although the sensing of the number of receptacles in the present invention has been described as measuring a voltage across parallel resistors  34  in receptacle assemblies  16 , resistive element  34  can be replaced with inductive or capacitive elements. Measured variation in the inductive or capacitive elements can be accomplished by utilizing an alternating waveform and a voltage sensing circuit. Alternatively, active circuit elements can be used as coding element  34  in a similar manner to convey information to circuit assembly  22 . 
     Alternatively, optic signals carried on fiber optic interconnections can be used instead of electrical ones to thereby determine the number of receptacle assemblies  16  that are sequentially connected. Coding elements  34  then would be in the form of optical elements that alter a signal on the fiber optic connection. 
     While this invention has been described as having a preferred design, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.