Patent Publication Number: US-9407033-B2

Title: Electric power receptacle

Description:
BACKGROUND OF THE INVENTION 
     1. Technical Field 
     The present invention relates generally to electric power receptacles. More particularly, the invention relates to electric power receptacles in furniture power distribution units. 
     2. Background Art 
     Electric power receptacles provide electric power to an electrical device. Typically, electric power receptacles provide power from a 120 Volt (V) 60 Hertz (Hz) alternating current (AC) mains power supply. 
     Furniture power distribution units (FPDU) incorporate an electric power receptacle into stationary or fixed furniture in residential and commercial facilities. For example, an outlet may be placed in a chair for providing electric power to a user while sitting in the chair. 
     Tabletop control and cable management devices are employed in a corporate facility to provide a control and communication interface to users. In particular, touch screens incorporating some combination of a graphical user interface (GUI), control buttons, audiovisual (AV) and communication ports are increasingly being installed in corporate environments. Users desire that these touch screen devices include an electric power receptacle to provide power to various business and presentation devices such as laptop and tablet computers, smartphones, projection devices and speakers. 
     To be certified by certain safety organizations, FPDUs with electric power receptacles must conform to particular specifications or complete certain tests. One such test is a dielectric voltage withstand test, such as the type required by Underwriter Laboratories (UL) headquartered in Northbrook, Ill. A dielectric voltage withstand test involves placing a high voltage across the insulation barrier of a device for a certain period of time after a liquid is spilled in the receptacle. If the insulation holds the voltage after a spill, the device is deemed to have passed the test. 
     There is now a need for a tabletop interface device that includes an electric power receptacle in conformance with certain certification standards for a furniture power distribution unit. 
     SUMMARY OF THE INVENTION 
     It is to be understood that both the general and detailed descriptions that follow are exemplary and explanatory only and are not restrictive of the invention. 
     DISCLOSURE OF INVENTION 
     Principles of the invention provide a tabletop interface device including a spill resistant electric power receptacle. In a first aspect, an electric power receptacle includes a main receptacle body and a rear receptacle cover. The main receptacle body includes one or more cavities. Each of the cavities is configured for receiving an electrical contact further include a drainage slot configured for facilitating liquid drainage from the cavity and a rib slot configured for receiving an isolation rib. The one or more rear receptacle covers are configured for removably fastening to the main receptacle body and further include at least one contact support for supporting an electrical contact and an isolation rib protruding from the rear receptacle cover and configured for isolating the one or more cavities of the main receptacle body when the rear receptacle cover is coupled to the main receptacle body via communication between the one or more rib slots and the isolation rib. 
     In a second aspect, an interface device includes a bucket portion configured for being inserted into an opening of a surface. The bucket portion further includes an electric power receptacle and the electric power receptacle includes an external housing, a main receptacle body and a rear receptacle cover. The external housing is configured for being affixed to the bucket portion. The main receptacle body includes a front face, a first cavity, second cavity, third cavity, fourth cavity, fifth cavity and sixth cavity. The front face includes a hot plug terminal, neutral plug terminal and ground pin terminal. Each of the hot plug terminal, neutral plug terminal and ground pin terminal are configured for receiving a plug. Each of the first cavity, second cavity and third cavity comprise a drainage slot and a rib slot. Each of the one or more cavities and the drainage slots are dimensioned to drain liquid entering through an opening in a front face of the main receptacle body at a rate such that the liquid does not breach the opening in the front face. The rear receptacle cover further includes at least one contact support for supporting an electrical contact and an isolation rib. The isolation rib protrudes from the rear receptacle cover and configured for isolating the one or more cavities of the main receptacle body when said rear receptacle cover is coupled to the main receptacle body via communication between the one or more rib slots and the isolation rib. 
     The present invention seeks to overcome or at least ameliorate one or more of several problems, including but not limited to: providing a touch screen with an electric power receptacle that is spill resistant. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The accompanying figures further illustrate the present invention. 
       The components in the drawings are not necessarily drawn to scale, emphasis instead being placed upon clearly illustrating the principles of the present invention. In the drawings, like reference numerals designate corresponding parts throughout the several views. 
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
         FIG. 1  is a touch screen assembly with a spill resistant electric power receptacle in accordance with an illustrative embodiment of the invention. 
         FIG. 2A  is a front view of a spill resistant electric power receptacle in accordance with an illustrative embodiment of the invention. 
         FIG. 2B  is a side view of the spill resistant electric power receptacle in accordance with an illustrative embodiment of the invention. 
         FIG. 2C  is a top view of the spill resistant electric power receptacle in accordance with an illustrative embodiment of the invention. 
         FIG. 2D  is a front perspective view of the spill resistant electric power receptacle in accordance with an illustrative embodiment of the invention. 
         FIG. 3  is an exploded view of the spill resistant electric power receptacle in accordance with an illustrative embodiment of the invention. 
         FIG. 4  shows the rear receptacle cover of the electric power receptacle in accordance with an illustrative embodiment of the invention. 
         FIG. 5A  is a side view of a main receptacle body for the spill resistant electric power receptacle in accordance with an illustrative embodiment of the invention. 
         FIG. 5B  is a back view of the main receptacle body for the spill resistant electric power receptacle in accordance with an illustrative embodiment of the invention. 
         FIG. 5C  is a front view of the main receptacle body for the spill resistant electric power receptacle in accordance with an illustrative embodiment of the invention. 
         FIG. 6  is a back perspective view of the spill resistant electric power receptacle with a portion of the external housing removed in accordance with an illustrative embodiment of the invention. 
     
    
    
     LIST OF REFERENCE NUMBERS FOR THE MAJOR ELEMENTS IN THE DRAWING 
     The following is a list of the major elements in the drawings in numerical order.
           1  touch screen assembly     10  electric power receptacle     12  bucket     14  lid     16  bezel portion     17  main receptacle body     19  rear receptacle cover (collectively the rear receptacle covers of a . . . b)     101  external housing (p/o of electric power receptacle  10 )     103  front plate (p/o of electric power receptacle  10 )     105  first outlet face     107  second outlet face     109  hot plug terminal (collectively the hot plug terminals of  109   a . . . b )     111  neutral plug terminal (collectively the neutral plug terminals of  111   a . . . b )     113  ground plug terminal (collectively the ground plug terminals of  113   a . . . b )     170  cavity (collectively the cavities of  170   a - f )     171  cavity wall (collectively the cavity walls of  171   a - f )     172  drainage slot (collectively the drainage slots of  172   a - e )     173  rib slot (collectively the rib slots of  173   a - e )     190  fastener opening (p/o rear receptacle cover  19  and collectively the fastener openings of  190   a - h )     191  fastener     192  hot contact support (collectively the hot contact supports of  192   a . . . b )     193  neutral contact support (collectively the neutral contact supports of  193   a . . . b )     194  ground pin support (collectively the ground supports of  194   a . . . b )     195  isolation rib (collectively the isolation ribs of  195   a . . . b )       

     DETAILED DESCRIPTION OF THE INVENTION 
     Mode(s) for Carrying Out the Invention 
     The present invention discloses a tabletop interface device comprising an electric power receptacle configured for being spill resistant. The electric power receptacle further comprises elongated electrical contacts which are isolated from each other by cavities in an elongated main receptacle body. A rear receptacle cover further comprises raised portions which interconnect with the main receptacle body forming isolated cavities to keep liquid from entering one cavity from another. Advantageously, the electric receptacle does not require potting or a hard-wire connection to ground. 
     The tabletop interface device is configured for providing an electric power receptacle to a surface such as a horizontal tabletop surface. The electric power receptacle may be a stand-alone device or may be part of a more robust assembly providing more functionality to a user. In an embodiment, the tabletop interface device is a touch screen interface providing cable connections and control buttons. The control buttons may be used to control devices such as lighting devices, shade devices, AV devices, HVAC devices, security devices or any other controllable device. For example, the tabletop interface device may be a Crestron® Connect-It Presentation Interface or a Crestron FlipTop™ Touch Screen or Touch Screen Control System available from Crestron Electronics, Inc. of Rockleigh, N.J. 
     When installed in a surface, the electric power receptacle of the tabletop interface may be flush with the table top surface, raised above, below the horizontal surface or some combination of the above. In addition, the electric power receptacle may be at an angle to the table top surface or parallel with the surface. Finally, the mounting surface may be a horizontal surface such as a table, a vertical surface such as a wall or at an angle such as on a podium. 
       FIG. 1  is a touch screen assembly  1  with a spill resistant electric power receptacle  10  in accordance with an illustrative embodiment of the invention. The touch screen assembly  1  comprises a bucket  12 , a lid  14 , and a bezel  16 . The touch screen assembly  1  is configured to be mounted on a surface such that the bucket  12  is inserted into an opening formed in the mounting surface and is substantially below the mounting surface when mounted. When mounted, the bezel  16  is in contact with and parallel to the mounting surface. 
     The touch screen assembly  1  further comprises a lid  14  which is a hinged lid similar to those found in the FlipTop™ line of touch screens available from Crestron Electronics of Rockleigh N.J. An exterior surface of the lid  14  provides a cover for the bucket  12  of the touch screen assembly  1  when in a closed position. When in a closed position, the lid  14  of the touch screen assembly is substantially parallel with the tabletop surface or at 0 degrees with the tabletop surface. The interior portion of the lid  14  provides a user interface when in an open position. An open position is any angle from greater than zero (0) degrees to one-hundred (180) degrees. 
     In the embodiment shown in  FIG. 1 , the lid  14  comprises a touch screen providing a graphic user interface as well as a plurality of physical buttons. In other embodiments, the lid  14  may provide some other arrangement of one or more of the following: touch screen, physical buttons, decorative face. 
     The bucket portion  12  further comprises an electric power receptacle  10  positioned such that a front face of the power receptacle  10  is facing toward the surface opening thereby providing convenient access for plugs. The electric power receptacle  10  is configured for providing electric power to one or more electrical devices via an inserted plug. In the embodiment shown in  FIG. 1 , the electric power receptacle  10  is a duplex receptacle offering two outlets. In other embodiments, the electric power receptacle  10  may offer a single outlet or more than two outlets. 
     In corporate and residential installations in the United States, the electric power receptacle  10  will commonly provide power from an a 120 V 60 Hz AC mains power supply. In other embodiments, the duplex receptacle may be providing power at different voltage and frequency such as 230 V and 50 Hz. 
       FIG. 2A  is a front view of a spill resistant electric power receptacle in accordance with an illustrative embodiment.  FIG. 2B  is a side view of the spill resistant electric power receptacle in accordance with an illustrative embodiment.  FIG. 2C  is a top view of the spill resistant electric power receptacle in accordance with an illustrative embodiment.  FIG. 2D  is a front perspective view of the spill resistant electric power receptacle in accordance with an illustrative embodiment. 
     The electric power receptacle  10  comprises an external housing  101 . The external housing  101  protects a main receptacle body  17  and fastens to the touch screen assembly  1 . A front plate  103  of the external housing  101  is configured for being attached to a surface of the touch screen assembly  1  via four fastener holes formed in the front plate  103 . The front plate  103  further comprises two openings, each dimensioned for an outlet face  105 ,  107  to extend through the opening. 
     Electrical wires enter the external housing  101  through an opening in a rear face of the external housing  101 . For example, a hot conductor wire, neutral conductor wire and a ground conductor wire may enter the external housing  101  through the rear face of the external housing  101 . 
     In an embodiment, the external housing  101  is composed of two pieces of sheet metal. The two metal sheets are fastened via a fastener such as a threaded screw. 
     A first outlet face  105  and a second outlet face  107  protrude through the front plate  103 . The face of each receptacle provides a hot plug terminal  109 , a neutral plug terminal  111  and a ground pin terminal  113 . The hot plug terminal  109  and neutral plug terminal  111  are aligned with and dimensioned for receiving a first blade and a second blade of a plug. 
     The first outlet face  105  and second outlet face  107  are each aligned with and dimensioned to receive plugs compliant with industry standards such as the National Electrical Code (NEC) and the National Electrical Manufacturers Association (NEMA). In this embodiment, the dimensions of the openings are dimensioned as a standard receptacle in accordance with “NEMA 5-15”. Therefore, the hot plug terminal  109  and neutral plug terminal  111  of each electric receptacle are dimensioned to receive plug blades that comply with U.S. ANSI/NEMA standard WD 6-2002 sheet 1-15 (“NEMA 1-15”) for 110 V, 15 A, 2 wire plugs. That is to say, the neutral blade has a length that is between 0.625 and 0.718 inches, a height that is between 0.307 and 0.322 inches, and a width that is approximately 0.06 inches. The hot blade has a length that is between 0.625 and 0.718 inches, a height that is between 0.24 and 0.26 inches, and a width that is approximately 0.06 inches. 
     Although the embodiment shown in  FIG. 2A-D  includes hot and neutral plug terminals that are flat blades, the invention could also be applied to receptacles dimensioned to receive plugs having hot and neutral conductors in other shapes and orientations. These could include, for example, D- or U-shaped conductors of U.S. ANSI/NEMA standard WD 6-2002 sheet 5-15 (“NEMA 5-15”), or square, circular, L or T-shaped conductors. 
       FIG. 3  is an exploded view of the spill resistant electric power receptacle  10  in accordance with an illustrative embodiment. In this view, portions of the external housing  101  have been separated to show a main receptacle body  17 , a first rear receptacle cover  19   a  and a second rear receptacle cover  19   b . Each of the first rear receptacle cover  19   a  and the second rear receptacle cover  19   b  are dimensioned to interlock together. Each of the first rear receptacle cover  19   a  and second rear receptacle cover  19   b  further comprises four fastener openings  190   a - h  extending laterally through the portion and configured for each receiving a fastener  191   a - h , such as a threaded screw. Each of the eight total fastener openings  190   a - h  of the first rear receptacle cover  19   a  and second rear receptacle cover  19   b  is aligned with a corresponding fastener opening in the main receptacle body  17 . The corresponding fastener openings of the main receptacle body  17  receive a fastener  191   a - h , thereby securing the main receptacle body  17  to the first rear receptacle cover  19   a  and the second rear receptacle cover  19   b.    
     The first rear receptacle cover  19   a  and second rear receptacle cover  19   b  each further comprise a hot contact support  192   a - b  and a neutral contact support  193   a - b . The hot contact support  192   a - b , neutral contact support  193   a - b  and ground contact support  194   a - b , of each rear receptacle cover  19  protrude perpendicularly from the front face of the rear receptacle cover  19  and may be formed of a single piece of material with the rear receptacle cover body, such as from a single piece of plastic material at a specific grade to meet UL requirements. For example, the entire rear receptacle cover  19  may be formed from a single piece of plastic by a molding process, milling process or three dimensional printing process. Advantageously, this provides simple manufacturing and a minimum number of parts. 
     A ground contact may be attached to a ground support  194   a - b  protruding perpendicularly from the body of each of the first rear receptacle cover  19   a  and the second rear receptacle cover  19   b . Each of the hot contact support  192  and neutral contact support  193  is configured for supporting an electrical contact and the ground contact support is configured for supporting a ground contact. 
       FIG. 4  shows the first rear receptacle cover and second rear receptacle cover of the receptacle in accordance with an illustrative embodiment. Each electrical contact attaches to the contact support and is configured for making conductive contact with a plug blade and either supplying or returning electrical power to the power supply via a wire. In the embodiment shown, a portion of the contact support extends through an opening in the electrical contact, thereby affixing the electric contact to the contact support. Each receptacle cover comprises a first groove, second groove and third groove for supporting the hot wire, neutral wire and ground wire in conductive connection with the electric contact. 
     The first rear receptacle cover  19   a  of the receptacle and the second rear receptacle cover  19   b  of the receptacle each further comprise an isolation rib  195   a - b . The isolation rib is a raised portion in the shape of a “T”. Each isolation rib comprises a main arm bisecting each rear receptacle cover  19  between the hot contact support and neutral contact support. The isolation rib further comprises a minor arm perpendicular from the main arm and separating the hot contact support and neutral contact support thereby further quartering that bisected half of the rear receptacle cover  19 . As will be described in further detail below, the isolation rib  195   a - b  of each rear receptacle cover  19  ensure that fluid, such as a liquid, entering through the face of the receptacle does not form an electrical connection between two contacts supported by that portion, thereby causing a short. 
       FIG. 5A  is a side view of a main receptacle body of the spill resistant electric power receptacle in accordance with an illustrative embodiment.  FIG. 5B  is a back view of the main receptacle body of the spill resistant electric power receptacle in accordance with an illustrative embodiment.  FIG. 5C  is a front view of the main receptacle body of the spill resistant electric power receptacle in accordance with an illustrative embodiment. 
     The main receptacle body  17  of the receptacle comprises a first isolation cavity  170   a , a second isolation cavity  170   b , a third isolation cavity  170   c , a fourth isolation cavity  170   d , a fifth isolation cavity  170   e  and a sixth isolation cavity  170   f , each defined by an opening in a back surface of the main receptacle body  17 . Each of the cavities  170   a - f  extends into the main receptacle body  17  toward the face and forms cavity walls  171  surrounding each cavity. 
     The cavities  170  are aligned with the terminal openings of the outlet faces  105 ,  107 . The first cavity  170   a , second cavity  170   b , fourth cavity  170   d  and fifth cavity  170   e  are configured for receiving an electrical contact and a contact support  192 ,  193 . The third cavity  170   c  and sixth cavity  170   e  are configured to receive a ground support  194  and associated ground contact. 
     The main receptacle body  17  further comprises a plurality of drainage slots  172   a - e  formed of openings in the cavity walls  171 . The drainage slots  172   a - e  extend through the outside of the cavity wall  171  to the isolation cavity  170  and are positioned to allow any fluid such as a liquid that has entered a cavity  170 , such as through the receptacle openings in the front face of the receptacle, to drain from that cavity  170  without shorting the electrical contacts. For example, the fluid may comprise liquid water or water vapor or some combination of the two. In the embodiment shown in  FIG. 3 , the main receptacle body  17  comprises a drainage slot  172  for each cavity  170  formed from an opening on the outer cavity wall  171  extending along the length of the wall and perpendicular to the front face of the main receptacle body  17 . The drainage slots  172  extend from the rear surface of the main receptacle body  17  to substantially the front face of the main receptacle body  17 , thereby maximizing the length of the drainage slot. Substantially to the front face of the main receptacle body does not require that the drainage slot extend the entire depth of the main receptacle body as it may be structurally beneficial to have material between the edge of the drainage slot and the front face of the main receptacle body. 
     The cavities and the drainage slots are dimensioned such that liquid drains from each cavity  170  at a rate greater than it can accumulate in the cavity  170  after entering through a plug terminal of the face. In particular, the cavities  170 , electrical contacts and drainage slots are elongated to facilitate liquid drainage from the cavity  170 . In the embodiment shown in  FIGS. 5A, 5B and 5C , the depth of the main receptacle body  17  (i.e. the length of the cavity wall  171  from the rear surface of the main receptacle body  17  to the front surface of the main receptacle body  17  at the base of the outlet face) is approximately 1.48 inches. The height of the main receptacle body  17  at the rear surface is approximately 2.4 inches. The height of the outlet face  105 ,  107  is approximately 1 inch. Accordingly, the ratio of the depth of the main receptacle body  17 , and therefore the length of the drainage slot, to the height of the outlet face  105 ,  107  is approximately three to two. Approximately three to two comprises ratios within a reasonable range of three to two which result in liquid draining from the drainage slot at a rate which is greater than it can accumulate in the cavity  170  after entering through a plug terminal of the face. 
     The main receptacle body  17  further comprises rib slots  173  formed in the opening in the cavity wall  171 . The rib slots  173  are configured for receiving and communicating with the isolation ribs  195  of each of the rear receptacle covers  19   a - b  to further isolate each cavity  170  from the other cavities and ensure liquid which has entered one or more of the cavities does not create a short between electric contacts. 
     In an embodiment, the isolation rib  195  of each rear receptacle cover  19  is formed integrally from one piece of material, such as from a single piece of plastic material, with that rear receptacle cover  19   a - b . For example, the entire rear receptacle cover  19  may be formed from a single piece of plastic at a specific grade to meet UL requirements and by a molding process, milling process or three dimensional printing process. Advantageously, this provides simple manufacturing and a minimum number of parts. Additionally, this provides convenient alignment and assembly with the main receptacle body  17 . Alternatively, in another embodiment, the isolation rib  195  of each rear receptacle may be a mechanical gasket, such as an elastomer configured to attach to the rear receptacle cover  19  such as by fitting in a corresponding groove of the rear receptacle cover  19 . 
     The drainage slots  172 , in conjunction with the isolation ribs  195  and the rib slots  173 , ensure that liquid entering a cavity  170  through the faceplate will drain out of the cavity  170  and away from any other electric contact. Accordingly, the electric contacts will not be shorted by any liquid entering and the receptacle can adequately pass a dielectric withstand test. 
       FIG. 6  is a back perspective view of the spill resistant electric power receptacle with a portion of the external housing  101  removed in accordance with an illustrative embodiment. The receptacle shown in  FIG. 5  is connected as it would be during operation. The main receptacle body  17  and the first rear receptacle cover  19   a  and second rear receptacle cover  19   b  are interconnected, with the isolation ribs  195  inserted into the isolation slots  173 . The eight threaded screws  191  are inserted through the fastener openings  190 ,  170  in the first rear receptacle cover  19   a , second rear receptacle cover  19   b  and the main receptacle body  17  thereby securing the three portions together. 
     The electric contacts are connected to a power supply by a plurality of wires protruding through the external housing  101 . A hot wire enters the external housing  101  and is connected to a first internal hot wire and a second internal hot wire via a wire connector. The first and second internal hot wire each supply electric power to an electrical contact in each receptacle. A neutral wire enters the external housing  101  and is connected to a first internal neutral wire and a second internal neutral wire via a wire connector. The first and second internal neutral wire each supply a return path to an electrical contact in each receptacle. A ground wire enters the external housing  101  and is connected to a common ground attached to the external housing  101 . A ground wire runs from each ground contact to the common ground. 
     INDUSTRIAL APPLICABILITY 
     To solve the aforementioned problems, the present invention is a unique device in which an electric power receptacle  10  is provided in a touch screen assembly  1 . The electric power receptacle  10  provides a fluidly isolated environment for each contact thereby allowing the electric power receptacle  10  to pass a dielectric withstand test. 
     LIST OF ACRONYMS USED IN THE DETAILED DESCRIPTION OF THE INVENTION 
     The following is a list of the acronyms used in the specification in alphabetical order.
         A ampere   AC alternating current   ANSI American National Standards Institute   AV audiovisual   FPDU furniture power distribution unit   GUI graphical user interface   HVAC heating, ventilation, air conditioning   Hz Hertz   In inch   NEC National Electrical Code   NEMA National Electrical Manufacturers Association   UL Underwriters Laboratory   V Volt       

     ALTERNATE EMBODIMENTS 
     Alternate embodiments may be devised without departing from the spirit or the scope of the invention. For example, the electrical receptacle may accept plugs of a different size and orientation than a NEMA 5-15 plug.