Abstract:
Devices, systems and methods for regulating the distribution of electricity at events such as trade shows to prevent exhibitors from utilizing electricity not purchased from the convention center or other entity controlling electricity distribution, including lockable electric outlet boxes having a lockable fuse holder containing a fuse that restricts or limits a specific electrical outlet box or group of outlet boxes to a maximum electrical current or amperage.

Description:
[0001]    The present application claims priority on U.S. application 60/900,499, filed Feb. 9, 2007, entitled “Electrical Power Control Outlets, Methods of Use and Systems”, which is incorporated by reference herein. 
     
    
     FIELD OF INVENTION 
       [0002]    The present power control outlet, method of use and system relates generally to devices and systems for regulating the distribution of electricity at events such as trade shows to prevent exhibitors from utilizing electricity not purchased from the convention center or other entity controlling electricity distribution. Specifically, the invention relates to lockable electric outlet devices and systems that restrict or limit a specific electrical outlet or group of outlets to a maximum electrical current or amperage 
       BACKGROUND OF INVENTION 
       [0003]    At trade shows, exhibitors typically purchase electrical power or are allotted a certain amount of electrical power from a convention center provider and the convention center provider typically supplies electrical power to the exhibitors via power strips supplied by a master power distribution system which is in turn power by public utility. The power strips typically contain individual electrical outlets, or groups of outlets that are placed behind the exhibitors&#39; booths. Typically the fee for rental of exhibition space includes a fee for a specified amount of electrical power. One problem in this regard has been use by exhibitors of more electrical power than was purchased by the exhibitor(s). Excess us of electrical power by one or more exhibitors then creates problems with the electrical distribution system itself, which problems are in addition to the problem of use of electrical power without payment to the provider. These electrical system problems include the potential for overloading the entire convention facility master power distribution system, as well as leaving some of exhibitors with an insufficient supply of electrical power, depending of course on how the master power distribution system for the entire convention center is configured. There is currently no known device or system that attempts to solve this problem, and there is no known device that limits the amount of electrical power that each individual outlet, group of outlets, power strip or group of power strips is allocated from the master power distribution system presently used in convention centers or facilities used for conventions. 
       SUMMARY OF THE INVENTION 
       [0004]    It is an object of the invention to provide a device that regulates the quantity of electricity allotted to convention exhibitors at trade shows, and other special events. The device isolates a specific outlet to specific amperage of a shared or multiple circuits. If an individual outlet utilizes a greater quantity of electricity than the specific amperage that has been allotted, a fuse inside the distribution box will break, suspending electricity flow to that outlet. An indicator light on the outer surface of the distribution box will cease to emit light when a fuse breaks and electricity ceases to flow through the circuit. 
         [0005]    The invention comprises a device that is connected to a master power distribution system that is commonly used to distribute electricity to exhibitors at trade shows and other special events and functions to limit the rate of current supplied from the device by having a lockable, fuse containing fuse holder in circuit whereby the fuse is blown or opened upon the exhibitor drawing power out of the outlet at a rate greater than permitted by the fused circuit. 
         [0006]    The device includes a circuit box containing one or more fuses, a power cord, one or more receptacles, a light emitting diode (LED) for indicating power availability, or an energized system, a fuse holder, one or more fused in the fuse holder, a locking mechanism that functions to prevent access to the fuse holder without the key for the lock, and wiring to and from the power cord to the receptacle(s) that forms an electrical circuit. The housing also has a recessed area adapted to accommodate a panel mount fuse holder which contains one or more fuses including, for example, a 5, 10 or 20 ampere current limiting, type G fuse. Also included is a locking bar type mechanism on the fuse holder secured by a barrel type lock to prevent tampering with the fuse holder. The power line to the fuse is attached to the fuse holder with, preferably, a spade tongue solderless connector. Duplex receptacles are preferably wired in circuit by mechanical means such as solderless eyelets. The preferred power cord is a three-wire cable, for example a 12-gauge SJOOW cable, having rubberized neoprene/thermoset or similar materials rubber like in construction, suitable for indoor use, with oil and water resistant outer jacket, oil resistant inner conductors. The preferred power cord plug is a twist type locking molded plug, for example a NEMA type L5-20, 20 ampere, 125 volt, twist type locking molded plug; and, the power cord attaches to the power control housing with a strain, no strain or no snag strain relief fitting, such as for example, a molded strain relief fitting. The device is connected to a master power distribution system that is commonly used to distribute temporary electricity to trade shows and other special events, and provide power to individual exhibitor sites or areas in accordance with predetermined agreements. 
         [0007]    The device has the capability to prevent circuit breaks in the master power distribution system through limiting the amount of electricity users can exploit from the master power distribution system, thus preventing overloading of the master system and any resulting circuit break. 
         [0008]    The power control and locking device described herein provides electricity to multiple exhibitors in limited, regulated quantities. In its normal use, it prevents exhibitors from utilizing electricity that was purchased by or allotted to another exhibitor. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  is perspective view of a preferred embodiment electrical power control and locking device including a power cord and in an unlocked position; 
           [0010]      FIG. 2  is a perspective view of the  FIG. 1  embodiment showing the lock in the unlocked position, the key and the power cord plug; 
           [0011]      FIG. 3  is a bottom, partially disassembled view of the  FIG. 1  embodiment showing the fuse holder and the locking bracket in the unlocked position; 
           [0012]      FIG. 4  is a perspective view of the locking bar of the  FIG. 1  embodiment; 
           [0013]      FIG. 5  is a diagram of the circuit of the  FIG. 1  embodiment; and, 
           [0014]      FIG. 6  is a view of the interior of the  FIG. 1  embodiment showing the electrical connections of various components such as the outlets, wiring, fuse holder and power cord. 
       
    
    
       [0015]    Reference symbols or names are used in the Figures to indicate certain components, aspects or features shown therein. Reference symbols common to more than one Figure indicate like components, aspects or features shown therein. 
       DETAILED DESCRIPTION 
       [0016]    With reference to  FIGS. 1 and 2  the exterior of a preferred embodiment of the present electrical power control circuit and locking device  20  will be described. The device  20  is a circuit box that preferably includes a housing  22 , an electrical power cord  24 , one or more power receptacles  26 , such as an industrial grade, 20 ampere, nominal 115-125 VAC, NEMA 5-20 R configuration, duplex receptacle and a plug  21 . The housing  22  is preferably of an electrical insulator material, such as a plastic that is durable. The presently most preferred material is a translucent polycarbonate that has been injection molded in the shape and configuration shown. Also, the housing is preferably of a 2-piece, molded construction, the pieces of which are preferably fastened together with a plurality of conventional fasteners, such as screws. In the embodiment shown in  FIG. 1 , the two pieces are screwed together with eight Philips type screws inserted into recesses provided in the backside or bottom part  25  of the 2-part housing. 
         [0017]    The housing also preferably includes a light-emitting diode  28  (LED) semiconductor on the front, outer surface of the circuit box  20  that emits a continuous light when the electrical circuit is energized and ceases to emit light when a fuse breaks and/or electrical current is otherwise not available to the circuit, such as when the device is unplugged from a power supply. With reference to  FIG. 1 , the assembled housing is provided with an opening  30 , preferably at the end opposite that of the power cord, and into which a fuse holder  32  is positioned. The preferred fuse holder is commercially available from Ferraz Shawmut as its GPM-S, 600 v, 30 A panel mount model. The fuse holder  32  accommodates conventional fuses, one of which is shown at  68 , preferably with a 5, 10 or 20 amps, type G fuse. 
         [0018]    With reference to  FIGS. 1-3 , the box  20  is also provided with a locking mechanism that includes a locking bar  34 , a first locking bar housing portion  36 , a first locking bar housing portion recess  38 , a second locking bar housing portion  40  and a second locking bar housing portion recess  42 , all of which are preferably positioned on the housing  22  adjacent the fuse holder  32 . 
         [0019]    With reference to  FIGS. 1-4 , the locking bar or bracket  34  has length, width, and thickness that is sized to slide or reciprocate within the recesses  38  and  42 . Bar  34  also has a U-shaped region or channel  44  and a hole or aperture  46 . When in the locked position, the distal end or bottom of the U is pressed tightly against the top of the fuse holder  32 , and prevents the fuse holder cap  33  from being rotated to open the fuse holder and remove and replace the fuse contained therein. The hole or aperture  46  is for receiving the plunger or striker of a lock that in turn prevents the locking bar from being removed from the recess(es)  38  and/or  42 . As shown in  FIG. 3 , lock  48  is positioned within lock channel, or cavity  50  in the second locking bar housing portion  40 . Preferably the lock is a barrel type, keyed lock having a single plunger or striker and a key  47 . Other types of locks can be used in the present power control and locking device, so long as it functions for its intended purpose of preventing unauthorized removal and replacement of the fuse. In the locked position, the locking bar is inserted fully into the recesses, the bottom part of the U-shaped portion of the locking bar is pressed against the cover of the fuse holder, and the lock plunger or striker extends through the hole  46  to thereby prevent sliding of the locking bar, and prevent access to the fuse holder. 
         [0020]    With reference to  FIGS. 5-6  the electrical circuit  52  is provided with a source of nominal 125 VAC electrical power through line  54  to each of the two receptacles  56 ,  58 , which are connected in parallel. The receptacles  56 ,  58  are also connected to ground via line  60  as shown in  FIG. 5 , and represented in  FIG. 6  with wires  62  and  64 . As shown in  FIGS. 1 ,  5  and  6  power is supplied via the power cord  24 , and the power line  54  is represented by wires shown connecting the receptacles  56  and  58 , the fuse holder  32  and the LED  28 . The fuse inside the fuse holder is shown as fuse  68  in  FIGS. 5 and 6 . The power cord is attached to the housing with a strain relief fitting  66 . While one preferred embodiment is provided for a specific 125 VAC power distributions system, other embodiments that accommodate other voltages, and other currents may be constructed using the principles explained herein. 
         [0021]    As may be seen from the above description, the locking mechanism prevents tampering with and unauthorized access to the fuse holder. Thus, when electrical loads are placed on the circuit in any single power box that exceeds the current limit for the installed fuse, the fuse will blow, and the host or other administrative authority will eventually become aware of the situation. In this way when an exhibitor uses his/her assigned electrical power box, or permits its use to exceed the amount of electrical power purchased from the convention center provider, the power will stop and the exhibitor will have to contact the convention center provider to remedy the situation. 
         [0022]    Although specific embodiments of the invention have been described, various modifications, alterations, alternative constructions, and equivalents are also encompassed within the scope of the invention. 
         [0023]    The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense. It will, however, be evident that additions, subtractions, deletions, and other modifications and changes may be made thereunto without departing from the broader spirit and scope of the invention as set forth in the claims.