Abstract:
A system of electrical distribution within a building, which selectively energizes power sockets only when an appliance is connected to the socket and in need of power.

Description:
BACKGROUND 
     Common electrical sockets used for power distribution within structures such as homes and businesses have been used for efficient power transmission for decades. While efficient at power transfer, they have numerous shortcomings that are well known yet have never been addressed. The presence of a live uncovered or exposed conducting surface in today&#39;s sockets near the surface of the wall puts children at risk when they insert fingers or objects. If a power cord carrying power from the wall to an appliance is damaged, it creates a live wire outside of the wall, with similar (but greater) risks. 
     The danger of sockets requiring direct connection to transmit power can be addressed by creating resonance between an in-wall source and a wall surface sink, with the sink being connected to a power cable which supplies an appliance. This process is described in numerous U.S. Patents and applications, including U.S. Pat. Nos. 8,115,448, 8,106,539, 8,097,983, 8,084,889, 8,076,801, 8,076,800, 8,035,255, 8,022,576, 7,825,543, and 7,741,734. 
     While the resonance method eliminates the danger of a live wire in a socket, it does not eliminate risk from damage to the cable, nor is it as efficient as it could be if the in-wall source is always on. What is needed, then, is a method for conveniently turning the power on only when a bonafide wall surface sink is connected, and for cutting it off in the event of damage to the cable. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL DRAWINGS 
         FIG. 1  is a schematic representation of one embodiment of the control system when proper connections have been made and power is flowing through the socket. 
         FIG. 2  is a schematic representation of one embodiment of the control system when power is not flowing through the socket. 
         FIG. 3  is a schematic representation of an alternative embodiment of the control system featuring an external hub. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     For the purposes of this application, an “appliance” is any device that operates using mains power such as is typically found in homes and businesses. 
     A plug  10  and a socket  12  are so constructed as to mate with one another for the purposes of transmitting full power  24  capable of operating appliance  18 . The precise shape of the plug  10  and socket  12  do not matter as long as they can be securely connected to one another mechanically. Preferably, a self-centering design is used to easily secure the plug  10  into the socket  12 . The plug  10  and socket  12  are preferably designed to operate to transmit power  24  wirelessly from the socket  12  to the plug  10 . This minimizes the chance of contact between humans or animals and a live wire. However, it is also possible to construct this system with conventional plugs as are already common in homes and business throughout the world. 
     In one embodiment, shown in  FIG. 1 , a transmitter  11  located proximate the socket  12  transmits a radio frequency signal  14 , generated by the signal generator  13 , which uniquely identifies the particular socket  12  with which it is associated. The signal  14  may be compatible with IEEE 802.11 standards to permit the use of readily available hardware for its generation. Along with signal  14 , the socket  12  also constantly streams low power  15  sufficient to energize a few radio chips. Low power  15  is also preferably transmitted wirelessly from socket  12  to plug  10 . The low power  15  is insufficient to operate appliance  18  and also preferably insufficient to harm humans or animals who may come in contact with it. The transmitter  11  is intentionally designed to have a poor impedance match with the air, so that relatively little of the signal  14  is able to leak out. However, a receiver  17  located in the plug  10 , when placed the appropriate distance from the transmitter  11 , has a good impedance match, and the plug  10  therefore receives the signal  14  and low power  15 . The power cable  16  conveys the signal  14  and low power  15  to an appliance  18  with minimal loss. This may involve a dedicated waveguide, such as the familiar coaxial cable, or the signal  14  and low power  15  may be carried by the ordinary copper wires by which full power  24  to turn on the appliance  18  is transmitted, so that the power cable  16  will be of minimal size. The appliance  18  is provided with an antenna  19  that is so designed as to efficiently broadcast the signal  14 . The antenna  19  may be outside the appliance  18  housing, or it may be inside the housing. Preferably, the appliance  18  has a power switch which acts not only to connect and disconnect the full power  24  provided by the plug  10  to the appliance  18 , but also to connect and disconnect the signal  14  and low power  15  to the antenna  19 . 
     When the plug  10  is in the socket  12  ( FIG. 1 ) and the power switch on the appliance (if provided) is in the “on” position, the signal  14  carrying the socket  12  ID travels from the transmitter  11  to the receiver  17 , down the power cable  16 , and to the antenna  19 . Low power  15  travels from socket  12  to plug  10  down the cable  16  to turn on the radio chip connected to antenna  19  in appliance  18 . Signal  14  is broadcast into the air, and then received by a router  20  which communicates with a power controller  22 . The controller  22  may control full power  24  to all sockets  12  in the house or office, or there may be a separate controller  22  for each individual socket  12 . In either case, the sockets  12  are each subject to individual control. When the controller  22  receives the signal  14  identifying the socket  12 , it turns on full power  24  (for example at 110V or greater as required for the operation of the appliance) to that socket  12  and that socket  12  only. Other sockets  12  remain unchanged. The controller  22  may use any well-known means, such as relays, to accomplish this. For as long as the router  20  continues to receive the signal  14 , the controller  22  maintains power  24  to the socket  12 . If the power switch on the appliance  18  (if provided) is turned off or the plug  10  pulled out of the socket  12  ( FIG. 2 ), the connection between the transmitter  11  and the antenna  19  is broken. The broadcast of the signal  14  ceases, and the controller  22  turns off full power  24  to the socket  12 . In like fashion, if the cable  16  is cut or broken, the cable  16  ceases to convey the signal  14  to the antenna  19 , with the same effect. Electrocution hazard is greatly reduced. There is never full power  24  to the socket  12  unless a bonafide appliance  18  that can complete the communication loop with the router  20  is plugged in, and unplugging or damaging the cable  16  cuts full power  24 . (Low power  15  is still provided.) If the socket  12  is of the wireless type as is preferable, there are never live surfaces near the wall, either. In addition, there is no need for power switches to be capable of switching heavy loads within the appliance  18  because that can be handled by the system in the wall. This is of particular advantage for high-current inductive loads, such as those involving electric motors. 
     For certain appliances  18 , the power switch would not be connected to the antenna  19 . For instance, a laptop computer might need to charge its battery even when the computer is turned off. The antenna  19  in such a case would be continuously connected to the cable  16 , regardless of the status of the power switch. 
     A power strip  26  or extension cord with multiple sockets  28  may contain a local controller that may assign a unique ID to each of its sockets  28 , as shown in  FIG. 1 . When such a power strip  26  is connected to the wall socket  12 , it becomes necessary to transmit not only the ID of the wall socket  12  and low power  15 , but also the ID of each power strip socket  28 . The power strip  26  can use a fraction of the low power  15  transmitted from the wall socket  12  for each power strip socket  28 . Each socket  28  carries low power  15  and a signal  14  bearing both the wall socket&#39;s  12  ID and a unique ID for each power strip socket  28 . When an appliance  18  is connected to the power strip  26 , its antenna  19  receives and transmits two identifiers: one for the wall socket  12 , and one for the power strip socket  28 . The controller  22  then energizes the appropriate wall socket  12 , and at the same time transmits the power strip socket  28  ID through wall socket  12 , where it is received by the power strip  26 . The local controller then energizes only the power strip socket  28  whose ID is received from the wall socket  12 . Multiple power strip sockets  28  are activated by the transmission of multiple IDs through the wall socket  12  in the same manner when appliances  18  are connected to those power strip sockets  28 . Sockets in the power strip without a bonafide appliance  18  connected to them are not energized or activated. 
     In an alternative embodiment shown in  FIG. 3 , the signal is not transmitted directly to the router  20 . Rather, the appliance  18  communicates with the controller  22  through an external hub  30 , such as a cell-phone system. In this embodiment, the appliance  18  does not send the signal  14  directly to the router  20 . Rather, the appliance  18  sends the signal  14  to the external hub  30 , which then generates a message  32  to transmit to the router  20 . The system may incorporate a gateway  34  capable of receiving a signal  14  and the message  32  and converting each of them to a new form of encoding, as is known in the art, so that the appliance  18  need not generate sufficient power by itself to reach the external hub  30 , nor be compatible with all possible external hubs  30 . In one embodiment, communications from the appliance  18  or router  20  to the gateway  34  are encoded based on IEEE 802.11, and communications between the gateway  34  and the external hub  30  are based on cellular telephone protocols. These protocols include but are not limited to IEEE 802.16 (known in the art by the trademark WIMAX), 3GPP Releases (including Release 8 and later, known in the art as LTE or “Long Term Evolution”), and standards promulgated by the International Telecommunications Union (including IMT-Advanced), and revisions thereof. These protocols are all well known in the art and are available to the public, and are hereby incorporated in their entirety by reference. Other protocols may also be employed, including those not yet described or even conceived. The message  32  may be passed through the gateway  34  if one is used, or it may be received directly by the router  20 . Because of bandwidth limits, it may be desirable to generate an “on” message  32  and an “off” message  32  in response to the receipt or non-receipt of the signal  14  by the external hub  30 , rather than transmitting the message  32  continuously as in the strictly local system described above. In addition to the advantages described above when a strictly local system is used, the use of the external hub  30  permits power  24  to individual sockets  12  to be controlled remotely. Thus, for instance, a user with a smartphone, tablet computer, or other internet-capable device could activate heating or air conditioning at home before leaving work, so that the temperature inside the house would be comfortable upon arrival. Alternatively, a computer could be programmed to activate lights, television, radio, and other devices in order to give the impression that a vacant house is occupied. 
     The terms and expressions which have been employed in the foregoing specification are used therein as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding equivalence of the features shown and described or portions thereof, it being recognized that the scope of the invention is defined and limited only by the claims which follow.