Patent Publication Number: US-7914292-B2

Title: Electric plug and method of providing the same

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims priority to U.S. Provisional Patent Application 61/106,071, filed on Oct. 16, 2008, and U.S. Provisional Patent Application No. 61/240,988, filed on Sep. 9, 2009; the contents of both applications are incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates generally to an electrical plug and, more particularly, to an electrical plug having a low profile housing and a rotatable electrical cord. 
     BACKGROUND 
     Conventional electrical plugs can be undesirable because they typically include a housing designed to protrude a substantial distance from the outlet surface, such as, for example a wall when the plug is inserted into a wall outlet contained with the wall. This protrusion causes the plug to be susceptible to unintentional disengagement by: objects moving near the wall outlet, such as, for example persons or objects a person may be carrying; objects being placed close to the wall, such as, for example furniture, computing equipment, consumer electronics and the like; or any such other objects that may come into close proximity to a wall outlet. 
     Many varieties of electrical plugs have been developed which have low profile housings. These electrical plugs with low profile housings are advantageous because they have a reduced housing profile in comparison to conventional electrical plugs. As such, electrical plugs with low profile housings can be less susceptible to unintentional disengagement and may permit objects to be placed closer to a wall outlet, and therefore its associated wall, than is possible with conventional plugs. 
     Most electrical plugs with low profile housings include a power cord that exits the plug perpendicular to the prongs of the plug so as to decrease the profile of plug&#39;s housing. Therefore, when the plug is inserted into a wall outlet, the power cord exits the plug housing parallel to the face of the wall outlet. Unfortunately, this configuration may prove undesirable because it is possible for the cord to block other receptacles in the outlet after it exits the low profile housing. Blocking receptacles prevents additional plugs from being inserted into the outlet. This is even more of a problem with polarized plugs or plugs incorporating a ground prong since these plugs can only be inserted into the wall outlet in a single orientation. 
     Therefore, a need exists in the art to develop electrical plugs with low profile housings and related methods thereto that address such limitations of the current technology. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be better understood from a reading of the following detailed description of examples of embodiments, taken in conjunction with the accompanying figures in the drawings in which: 
         FIG. 1  illustrates an isometric top view of an embodiment of an exemplary rotatable electric plug in accordance with the present disclosure, in accordance with the subject matter described herein. 
         FIG. 2  illustrates an isometric bottom view of the exemplary rotatable electric plug of  FIG. 1 , in accordance with the subject matter described herein. 
         FIG. 3  illustrates an isometric exploded left side view of the rotatable electric plug of  FIG. 1 , in accordance with the subject matter described herein. 
         FIG. 4  illustrates an isometric exploded right side view of the rotatable electric plug of  FIG. 1 , in accordance with the subject matter described herein. 
         FIG. 5  illustrates an isometric translucent top view of the rotatable electric plug of  FIG. 1 , in accordance with the subject matter described herein. 
         FIG. 6  illustrates an isometric translucent bottom view of the rotatable electric plug of  FIG. 1 , in accordance with the subject matter described herein. 
         FIG. 7  illustrates an isometric exploded right side view of another embodiment of a rotatable electric plug, in accordance with the subject matter described herein. 
         FIG. 8  illustrates a cutaway isometric top view of the rotatable electric plug of  FIG. 7 , in accordance with the subject matter described herein. 
         FIG. 9  illustrates an isometric exploded right side view of yet another embodiment of a rotatable electric plug, in accordance with the subject matter described herein. 
         FIG. 10  is a flow chart illustrating an example of a procedure of providing a rotatable electric plug. 
     
    
    
     For simplicity and clarity of illustration, the drawing figures illustrate the general manner of construction, and descriptions and details of well-known features and techniques may be omitted to avoid unnecessarily obscuring the invention. Additionally, elements in the drawing figures are not necessarily drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help improve understanding of embodiments of the present invention. The same reference numerals in different figures denote the same elements. 
     The terms “first,” “second,” “third,” “fourth,” and the like in the description and in the claims, if any, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments described herein are, for example, capable of operation in sequences other than those illustrated or otherwise described herein. Furthermore, the terms “include,” and “have,” and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, device, or apparatus that comprises a list of elements is not necessarily limited to those elements, but may include other elements not expressly listed or inherent to such process, method, system, article, device, or apparatus. 
     The terms “left,” “right,” “front,” “back,” “top,” “bottom,” “over,” “under,” and the like in the description and in the claims, if any, are used for descriptive purposes and not necessarily for describing permanent relative positions. It is to be understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments of the invention described herein are, for example, capable of operation in other orientations than those illustrated or otherwise described herein. 
     The terms “couple,” “coupled,” “couples,” “coupling,” and the like should be broadly understood and refer to connecting two or more elements or signals, electrically, mechanically or otherwise. Two or more electrical elements may be electrically coupled, but not mechanically or otherwise coupled; two or more mechanical elements may be mechanically coupled, but not electrically or otherwise coupled; two or more electrical elements may be mechanically coupled, but not electrically or otherwise coupled. Coupling (whether mechanical, electrical, or otherwise) may be for any length of time, e.g., permanent or semi-permanent or only for an instant. 
     “Electrical coupling” and the like should be broadly understood and include coupling involving any electrical signal, whether a power signal, a data signal, and/or other types or combinations of electrical signals. “Mechanical coupling” and the like should be broadly understood and include mechanical coupling of all types. The absence of the word “removably,” “removable,” and the like near the word “coupled,” and the like does not mean that the coupling, etc. in question is or is not removable. 
     DETAILED DESCRIPTION 
     In one embodiment, a rotatable electric plug includes a housing, a contact support subassembly, a contact array, a blade array, a rotation plate, and a power cord. The housing can include a top piece having an interior surface and an exterior surface and including a first opening. The housing also can include a bottom piece having an interior surface and an exterior surface, where the bottom piece is in mechanical communication with the top piece. A first cavity can be defined by the interior surface of the top piece and the interior surface of the bottom piece, the first cavity including a second opening. The contact support subassembly can have a top surface and a bottom surface and can be located within the first cavity. The contact support subassembly also can have a third opening in communication with the bottom surface. The contact support subassembly can be mechanically coupled to the interior surface of the bottom piece and can form a second cavity in communication with the third opening. The top of the contact support subassembly can include a plurality of contact support subassembly slots. The contact array can be in mechanical communication with the top surface of the contact support subassembly, and the contact array can include a plurality of concentric contacts. Each one of the plurality of concentric contacts can include a tab passing through an associated one of the plurality of contact support subassembly slots. The blade array can be in slidable communication with the contact array, and the blade array can include a plurality of blades. Each blade of the plurality of blades can be in electrical communication with an associated one of the plurality of concentric contacts of the contact array. The rotation plate can have a top surface and a bottom surface, where the top surface of the rotation plate is sized to fit within the first opening. The rotation plate can include a plurality of rotation slots, where each rotation slot of the plurality of rotation slots is sized to receive an associated one of the plurality of blades of the blade array. The power cord can be configured to pass through the second opening into the first cavity and to further pass through the third opening into the second cavity. The power cord can have a plurality of wires, where each wire of the plurality of wires is configured to mechanically couple to and be in electrical communication with an associated one of the tabs of the plurality of concentric contacts. 
     Turning to the drawings,  FIG. 1  illustrates an isometric top view of an embodiment of an exemplary rotatable electric plug system  100  in accordance with one embodiment of the subject matter described herein. System  100  is merely exemplary and is not limited to embodiments presented herein. System  100  can be implemented in many different embodiments or examples not presented herein. In  FIG. 1 , rotatable electric plug system  100  includes rotatable electric plug head  110  and power cable  120 . Rotatable electric plug head  110  includes a top housing  111 , a bottom housing  112  in mechanical communication with top housing  111  and a rotatable plug assembly  130 . Rotatable plug assembly  130  includes rotation plate  140  and blade array  150  (as see in  FIGS. 3 ,  5  and  6 ). 
     In operation, top housing  111  and bottom housing  112  are mechanically coupled together and form a cavity wherein each of the wires contained within power cable  120  is in electrical communication with an associated blade of blade array  150  (detailed below). Furthermore, rotation plate  140  is in rotatable communication with a portion of top housing  111  and includes an associated slot for each blade of blade array  150 , thereby allowing blade array to be placed into electrical communication with an associated electrical socket. Because rotation plate  140  is in rotatable communication with housing  111 , blade array  150  can be rotated to substantially any position required to interface with the aforementioned electric socket (detailed below). 
       FIG. 2  illustrates an isometric bottom view of an embodiment of an exemplary rotatable electric plug system  200  in accordance with one embodiment of the subject matter described herein. System  200  is merely exemplary and is not limited to embodiments presented herein. System  200  can be implemented in many different embodiments or examples not presented herein. In  FIG. 2 , rotatable electric plug system  200  includes rotatable electric plug head  110  and power cable  120 . Elements numbered as in  FIG. 1  function in a substantially similarly way. 
       FIG. 3  illustrates an isometric exploded left side view of an exemplary rotatable electric plug system  300  in accordance with one embodiment of the subject matter described herein. System  300  is merely exemplary and is not limited to embodiments presented herein. System  300  can be implemented in many different embodiments or examples not presented herein. Elements numbered as in  FIGS. 1 and 2  above function in a substantially similarly way. In  FIG. 3 , rotatable electric plug head  110  includes top housing  111  having an opening that is disposed to contain rotatable plug assembly  130 , and bottom housing  112  configured to mechanically couple to top housing  111 . Top housing  111  and bottom housing  112  are coupled to form a cavity to at least partially contain rotatable plug assembly  130  as well as a connecting end portion of power cable  120 . As described above, rotatable plug assembly  130  includes rotation plate  140  located within the cavity formed by top housing  111  and bottom housing  112 , and further includes blade slots to accommodate the passage of associated blades of blade array  150 . Rotation plate  140  is configured to slidably fit with the opening of top housing  111  and maintain rotatable plug assembly  130  within the cavity formed by top housing  111  and bottom housing  112 . In one embodiment, the opening of top housing  111  is delimited by a housing flange, where the housing flange is complementary with a plate flange at the perimeter of rotation plate  140  to thereby restrict rotatable plug assembly  130  from exiting through the opening of top housing  111 . 
     As described above, rotatable plug assembly  130  additionally includes blade array  150  having plug blades  151 - 153 . Plug blades  151 - 153  are sized to be received through the associated blade slots located in the face of rotation plate  140 , and configured such that a portion of each of blade in blade array  150  is retained within the cavity formed by top housing  111  and bottom housing  112 . In some embodiments, plug blade  151  (e.g., a ground plug blade) further includes a plug link  154 , plug blade  152  is mechanically coupled to a leaf spring contact  155  via a rivet  156 , and plug blade  153  further includes a plug link  157 . In these embodiments, plug links  154  and  157  and leaf spring contact  155  are slidably coupled to the associated concentric contacts of contact array  160  within rotatable plug assembly  130 . 
     As described above, rotatable electric plug head  110  additionally includes contact array  160  having a plurality of concentric contacts. In some embodiments, the plurality of concentric contacts of contact array  160  are substantially circular with the largest of the concentric contacts of contact array  160  sized to fit within the cavity formed by top housing  111  and bottom housing  112 . In an example and referring to  FIG. 3 , contact array  160  includes three (3) substantially circular concentric contacts. In  FIG. 3 , each concentric contact of contact array  160  is configured to slidably couple to and be in electrical communication with an associated plug blade of blade array  150 . Additionally and further detailed in  FIG. 4  below, each of the substantially circular concentric contacts of contact array  160  includes a corresponding tab oriented substantially perpendicular to its associated concentric contact and further oriented away from its concentric contact&#39;s associated plug blade of blade array  150 . Although power cable  120  is illustrated above contact support  170  so as to illustrate mechanical coupling of its individual wires to the associated tabs of contact array  160 , it should be understood that end of power cable  120  is located within the cavity created by contact support  170  and bottom housing  112  (detailed below). 
     In  FIG. 3 , rotatable electric plug head  110  further includes contact support  170  having a base and a sidewall that substantially conforms to fit within the cavity formed by top housing  111  and bottom housing  112 , such as, for example, a circular sidewall that runs along the interior wall of bottom housing  112 . In some embodiments, the base of contact support  170  is configured to receive the concentric contacts of contact array  160  and is further configured to provide electrical insulation between each of the contacts, such as, for example, via grooves configured within the base to accommodate the concentric contacts of contact array  160 . Further to the embodiment, contact support  170  includes a plurality of positioning slots, each of the positioning slots configured to receive an associated tab of an associated concentric contact of contact array  160 . In other embodiments, contact support  170  is configured to form an inner cavity opposite the surface of its base to receive a portion of cable  120  and to facilitate the coupling of wire leads of cable  120  to associated tabs of contact array  160 , where the associated tabs access the inner cavity through the associated positioning slots of contact support  170 . 
     In  FIG. 3 , rotatable electric plug head  110  additionally includes wave spring  180  located between the circular sidewall of contact support  170  and bottom housing  112 . Wave spring  180  is configured to provide pressure to maintain contact between the concentric contacts of contact array  160  and the associated plug blades of blade array  150 . The pressure is provided regardless of whether the plug blades of blade array  150  are in motion or are stationary relative to the concentric contacts of contact array  160 . 
       FIG. 4  illustrates an isometric exploded left side view of exemplary rotatable electric plug system  400  in accordance with one embodiment of the subject matter described herein. System  400  is merely exemplary and is not limited to embodiments presented herein. System  400  can be implemented in many different embodiments or examples not presented herein. Elements numbered as in  FIGS. 1-3  above function in a substantially similarly way. In  FIG. 4  and previously described above, rotatable electric plug head  110  includes contact support grooves  171  configured within the base of contact support  170  to accommodate the concentric contacts of contact array  160 . Rotatable electric plug head  110  additionally includes screws  113  to provide mechanical coupling of top housing  111  to bottom housing  112 . Additional methods for mechanically coupling top housing  111  to bottom housing  112  may be used, including, for example, ultrasonic welding, formed snaps, or solvent bonding attachment techniques. In  FIG. 4 , rotatable electric plug head  110  additionally includes strain relief  114  area within top housing  111  and bottom housing  112  that reinforce the end of power cable  120 . In some embodiments, strain relief  114  within top housing  111  and bottom housing  112 , which together enclose a portion of power cable  120 , includes one or more sets of teeth within the slotted/cord areas where a portion of power cable  120  resides. In this embodiment, the teeth can secure power cable  120  within rotatable electric plug  110 . 
       FIG. 5  is a see-through isometric front view illustrating an exemplary embodiment of a rotatable electric plug system  500  in accordance with one embodiment of the subject matter described herein. System  500  is merely exemplary and is not limited to embodiments presented herein. System  500  can be implemented in many different embodiments or examples not presented herein. Elements numbered as in  FIGS. 1-4  above function in a substantially similarly way. In  FIG. 5 , rotatable electric plug system  500  details the positioning of each of the blades within blade array  150  relative to each contact of contact array  160  that is slidably coupled to the base of contact support  170 . In  FIG. 5 , rotation plate  140  has been removed for visual representation. In some embodiments, the base of contact support  170  receives the contacts of contact array  160 , wherein all or a portion (e.g., the base) of contact support  170  is manufactured to have properties allowing portions of the contacts of contact array  160  to be received within the base, thereby providing electrical insulation between each of the contacts of contact array  160 . 
       FIG. 6  is a see-through isometric front view illustrating an exemplary embodiment of a rotatable electric plug system  600  in accordance with one embodiment of the subject matter described herein. System  600  is merely exemplary and is not limited to embodiments presented herein. System  600  can be implemented in many different embodiments or examples not presented herein. Elements numbered as in  FIGS. 1-5  above function in a substantially similarly way. In  FIG. 6 , tabs ( 161 - 163 ) associated with concentric contacts of contact array  160  extend through positioning slots (not shown) within contact support  170  and are mechanically coupled to and in electrical communication with individual wire leads ( 121 - 123 ) of power cable  120 . In some embodiments, the cavity formed by contact support  170  and bottom housing  112  (removed for visual reference) includes interior walls to provide spatial insulation and a physical barrier between each wire lead ( 121 - 123 ) of power cable  120  and its mechanical coupling to an associated tab (e.g., tab  161 ) of contact array  160  and the other wire lead/tab (e.g., tabs  162  and  163 ) mechanical couplings. 
     In some embodiments, top housing  111 , rotation plate  140 , contact support  170 , and bottom housing  112  can be manufactured from any suitable flame-rated materials, such as, for example, flame-rated acrylonitrile butadiene styrene (ABS) plastic, as available from GE Plastics of Pittsfield, Mass. In addition, top housing  111 , rotation place  140 , contact support  170 , and bottom housing  112  can be manufactured from other rigid or semi-rigid flame-rated thermoplastic materials, such as, for example, flame-rated polycarbonate plastic or polystyrene plastic. In other embodiments, plug blades  151 - 153  of blade array  150  and the concentric contacts of contact array  160  can be manufactured from any suitable electrically conducting material, such as, for example, copper alloys including brass and bronze alloys. 
     In other embodiments, the rotatable electric plug includes a cable stop. In this embodiment, a cable stop is configured to fit within a slotted area of bottom housing  112  and significantly reduce the movement of power cable  120  that is coupled to rotatable electric plug  110 . In still other embodiments, rotatable electric plug  110  does not include ground plug blade  151  as part of blade array  150 . In this embodiment, the concentric contacts of contact array  160  do not have three concentric rings, but instead have two concentric rings, and the base of contact support  170  is also modified accordingly. In this embodiment, each of plug blades ( 152  and  153 ) of plug array  150  can optionally have different sizes, particularly in an embodiment where the plug blades ( 152  and  153 ) of plug array  150  are polarized, so that plug blades ( 152  and  153 ) of plug array  150  couple to an electrical outlet in a specific orientation. 
       FIG. 7  illustrates an isometric exploded left side view of an exemplary rotatable electric plug system  700  in accordance with another embodiment of the subject matter described herein. System  700  is merely exemplary and is not limited to embodiments presented herein. System  700  can be implemented in many different embodiments or examples not presented herein. Elements numbered as in  FIGS. 1-6  above function in a substantially similarly way. In  FIG. 7 , rotatable electric plug head  710  includes top housing  111  having an opening disposed to contain the rotatable plug assembly, bottom housing  112  and a cable stop  725  configured to fit within a slotted area of bottom housing  112  and be coupled to power cable  120  to significantly reduce movement of power cable  120  coupled to rotatable electric plug head  710 . Each of top housing  111  and bottom housing  112  is configured to mechanically couple to the other and form a cavity between them. 
     In  FIG. 7 , rotatable electric plug head  710  additionally includes a rotatable plug assembly  730  having a rotation plate  740  and a blade array  750 . Rotation plate  740  is located within the cavity and includes a face having blade openings for receiving blades. Additionally, rotation plate  740  is configured to slidably fit within the opening of top housing  111  and maintain rotatable plug assembly  730  within the cavity formed by top housing  111  and bottom housing  112 . In some embodiments, top housing  111  is configured to include a flange along the inside opening and the flange is configured to include a complementary configuration to an associated recess at the perimeter of rotation plate  740 . 
     Blade array  750  includes two (2) plug blades sized to be received through two of the blade openings within the face of rotation plate  740 . The blades of blade array  750  are sized so that a portion of each blade is retained within the cavity. Blade array  750  additionally includes a ground plug blade sized to be received through a blade opening within the face of rotation plate  740 . The ground plug blade of blade array  750  is sized so that a portion of the ground plug blade is retained within the cavity. 
     In  FIG. 7 , rotatable electric plug head  710  further includes a contact array  760  having a set of concentric contacts where the largest of the concentric contacts is sized to fit within the cavity formed by top housing  111  and bottom housing  112 , and each of the concentric contacts of contact array  760  are configured to be in mechanical and electrical communication with an associated blade of blade array  750 . Rotatable electric plug head  710  additionally includes a pliable contact pad  770  configured to receive contact array  760  and provide electrical insulation between each of the contacts (detailed in  FIG. 8 , below) as well as provide sufficient pressure to maintain contact between the concentric contacts of contact array  760  and the associated blades of blade array  750  when the blades of blade array  750  are stationary and when the blades of blade array  750  are moving. In  FIG. 7 , rotatable electric plug head  710  additionally includes a pliable pad support  780  configured to receive pliable contact pad  770  and provide sufficient additional pressure, if necessary, to maintain contact between the concentric contacts of contact array  760  and the associated blades of blade array  750  when the blades of blade array  750  are stationary and when the blades of blade array  750  are moving. 
     In some embodiments, top housing  111 , bottom housing  112  and pliable pad support  780  including positioning slots, of rotatable electric plug head  710 , are manufactured using an injection molding process. In other embodiments, the plug blades of blade array  750  are stamped and formed so as to pass through rotation plate  740  with a portion of the plug blades of blade array  750  remaining within the rotatable plug assembly  730  area. In still other embodiments, the plug blades of blade array  750  are inserted into an injection mold and rotation plate  740  is formed fixing the plug blades of blade array  750  into rotation plate  740 . 
     In yet other embodiments, pliable contact pad  770 , including positioning slots, is formed via a thermal set molding and pliable contact pad  770  is placed on pliable pad support  780  forming a contact support subassembly. In this embodiment, the positioning slots (not shown) of pliable pad support  780  and pliable contact pad  770  are aligned. The concentric contacts of contact array  760  are manufactured using any suitable method, such as, for example stamping and forming of the concentric contacts of contact array  760  into concentric shapes and including tabs for extending through the positioning slots within pliable contact pad  770  and pliable pad support  780 . In this embodiment, the three wires of power cable  120  are then attached to the tabs of the concentric contacts of contact array  760  that protrude though the positioning slots of pliable pad support  780  portion of the contact support subassembly forming a contact support assembly. 
     Power cable  120  and the attached contact support assembly are then placed into bottom housing  112 . Rotation plate  740 , including the attached plug blades of blade array  750 , is placed into top housing  111 . Top housing  111  and bottom housing  112  are fitted and secured together, such as, for example by screws, ultrasonic welding, formed snaps, or solvent bonding attachment techniques. 
     Advantages of rotatable electric plug head  710  include rotation plate  740  having mounted plug blades of blade array  750 , where the plug blades of blade array  750  have integrated contacts, and pliable pad  770  provides electrical insulation between the individual concentric contacts of contact array  760  and maintains contact between the plug blades of blade array  750  and each associated concentric contact of contact array  760 . 
       FIG. 8  is a cutaway isometric view illustrating an embodiment of an exemplary rotatable electric plug system  800  in accordance with one embodiment of the subject matter described herein. System  800  is merely exemplary and is not limited to embodiments presented herein. System  800  can be implemented in many different embodiments or examples not presented herein. Elements numbered as in  FIG. 7  above function in a substantially similarly way. In  FIG. 8 , rotatable electric plug system  800  illustrates potential positioning of plug blades ( 751  and  752 ) and ground plug blade  753  relative to each concentric contact of contact array  760 , as well as illustrating potential interaction between pliable contact pad  770  and each concentric contact of contact array  760 . In this embodiment, pliable contact pad  770  is illustrated as receiving the concentric contacts of contact array  760 . Additionally, because pliable contact pad  770  is manufactured to have properties allowing portions of pliable contact pad  770  to reposition between each of the concentric contacts of contact array  760 , pliable contact pad  770  provides electrical insulation between each of the concentric contacts of contact array  760 . In this embodiment, pliable pad support  780  provides support for pliable contact pad  770 . Further to this embodiment, cable stop  725  is located within a slotted area of bottom housing  112  and provides significantly reduced movement of power cable  120  when coupled to the rotatable electric plug head  710 . 
       FIG. 9  illustrates an isometric exploded left side view of an exemplary rotatable electric plug system  900  in accordance with another embodiment of the subject matter described herein. System  900  is merely exemplary and is not limited to embodiments presented herein. System  900  can be implemented in many different embodiments or examples not presented herein. Elements numbered as in  FIGS. 1-8  above function in a substantially similarly way. In  FIG. 9 , pliable pad support  780  and bottom housing  112  of  FIG. 7  are replaced with a modified bottom housing  912  including formed ribs  980  configured to provide the functionality of the pad support  780  of  FIG. 7 , above. In one embodiment, modified bottom housing  912  can be manufactured using an injection molding process. 
     In  FIGS. 7-9 , top housing  111 , rotation plate  740 , pliable contact pad  770 , pad support  780 , and bottom housings  112  and  912  can be manufactured from any suitable flame-rated materials, such as, for example, flame-rated acrylonitrile butadiene styrene (ABS) plastic, as available from GE Plastics of Pittsfield, Mass. In addition, top housing  111 , rotation plate  740 , pliable contact pad  770 , pad support  780 , and bottom housings  112  and  912  can be manufactured from other rigid or semi-rigid flame-rated thermoplastic materials, such as, for example, flame-rated polycarbonate plastic or polystyrene plastic. In other embodiments, plug blades of blade array  750  and concentric contacts of contact array  760  can be manufactured from any suitable electrically conducting material, such as, for example, copper alloys including brass and bronze alloys. 
     In a different embodiment, the rotatable electric plug heads  710  and  910  do not include cable stop  725 . In this embodiment, top housing  111  and/or bottom housings  112  and  912  can optionally have one or more teeth within the slotted areas of top housing  111  and/or bottom housings  112  and  912 . Said teeth can secure cable  120  within the rotatable electric plug head. In the same or different embodiment, rotatable electric plug heads  710  and  910  do not include a ground plug blade. In these embodiments, the concentric contacts of contact array  160  do not have three concentric rings, but instead have two concentric rings, and pliable contact pad  770 , pad support  780 , and/or bottom housing  112  are also modified accordingly. Furthermore, in these embodiments, each of the plug blades of blade array  750  can optionally have different sizes, particularly in an embodiment where the plug blades of blade array  750  are polarized, so that plug the blades of blade array  750  couple to an electrical outlet in a specific orientation. 
       FIG. 10  illustrates an example of a method  1000  of providing a rotatable assembly. Method  1000  is merely exemplary and is not limited to embodiments presented herein. Method  1000  can be implemented in many different embodiments or examples not presented herein. 
     Method  1000  of  FIG. 10  includes a procedure  1010  of providing rotatable plug elements. The rotatable plug elements can include: a top housing, a bottom housing, a contact support, a contact array, a blade array, a rotation plate, and a power cord. The top housing can be the same as or similar to top housing  111  ( FIGS. 1-9 ); the bottom housing can be the same as or similar to bottom housing  112  ( FIGS. 1-8 ) or bottom housing  912  ( FIG. 9 ); the contact support can be the same as or similar to contact support  170  ( FIGS. 3-6 ) or contact pad  770  ( FIGS. 7-9 ); the contact array can be the same as or similar to contact array  160  ( FIGS. 3-6 ) or contact array  760  ( FIGS. 7-9 ); the blade array can be the same as or similar to blade array  150  ( FIGS. 3-6 ) or blade array  750  ( FIGS. 7-9 ); the rotation plate can be the same as or similar to rotation plate  140  (FIGS.  1  and  3 - 6 ) or rotation plate  740  ( FIG. 7-9 ); and the power cable can be the same as or similar to power cable  120  ( FIGS. 1-9 ). 
     Next, method  1000  continues with a procedure  1020  of coupling the rotation plate to the top housing. In some embodiments, a top surface of the rotation plate is configured to engage an opening in the top housing. In such an embodiment, the top surface of the rotation plate will be visible through an exterior surface of the top housing. 
     Subsequently, method  1000  has a procedure  1030  of sliding blades of the blade array though rotation slot of the rotation plate. The blades of the blade array can be similar to or the same as blades  151 - 153  ( FIG. 3 ). In some embodiments, the rotation plate has a separate slot for each of the blades of the blade array. Therefore, each blade is slid into its corresponding slot in the rotation plate. 
     After procedure  1030 , method  1000  continues with a procedure  1040  of coupling the blade array to the contact array. In some embodiments, the coupling of the blade array to the contact array comprises coupling the blade array so that it is in slidable communication with the contact array. Furthermore, in the same or other embodiments, each of the blades of the blade array is in electrical communication with a separate concentric contact of the contact array. 
     Next, method  1000  continues with a procedure  1050  of coupling the contact array to a surface of the contact support. In some embodiments, each of the separate concentric contacts of the contact array comprises a tab. Each of the tabs of the concentric contacts can pass through a separate slot in the contact support. As an example, the tabs can be the same as or similar to tabs  161 - 163  ( FIG. 6 ). In the same or different embodiment, procedure  1050  can include positioning the contact array over the contact support. 
     Then, method  1000  has a procedure  1060  of coupling each wire of the power cable to a separate tab of the concentric contacts. As an example, the wires of the power cable can be the same as or similar to wire leads  121 - 123  ( FIG. 6 ). The wires can be coupled to the tabs using any method of coupling. 
     After procedure  1060 , method  1000  continues with a procedure  1070  of coupling the top housing to the bottom housing. Any method may be used to couple the top housing to the bottom housing. For example, the top housing and the bottom housing can be coupled using ultrasonic welding, formed snaps, or solvent bonding. In another example, screws are used to couple the top housing to the bottom housing. As an example, the screws can be the same as or similar to screws  113  ( FIG. 4 ). In some embodiments, after the top housing and the bottom housing are coupled, an opening is created between the first housing and the second housing. In such embodiments, the power cable can pass through this opening. 
     Although  FIG. 10  illustrated various procedures of method  1000 , it will be understood by those skilled in the art that various changes can be made to method  1000  without departing from the scope of the invention. For instance, the order of the procedures can be altered. As one example, procedure  1030  can occur before procedure  1020 ; procedure  1040  can occur before procedure  1030 ; procedure  1050  can occur before procedure  1040 ; and/or procedure  1060  can occur before procedure  1050 . As another example, not all the plug elements described in reference to procedure  1010  above need to be provided at one time. It is possible that the power cable may not be provided until procedure  1060  is being performed. 
     In addition, additional procedures can be added to method  1000 . For example, method  1000  can include a procedure of providing a pressure mechanism. The pressure mechanism can be used to provide pressure to maintain contact between the concentric contacts of the contact array and the blades of the blade array. As an example, the pressure mechanism can be the same as or similar to wave spring  180  ( FIGS. 3-6 ) As best seen in  FIG. 6 , pressure mechanism  160  can be coupled to the contact support  170 , between contact support  170  and bottom housing  112 . In another example, pressure mechanism can be the same as or similar to pliable pad support  780  ( FIG. 7-9 ). In this example, pliable pad support  780  is coupled contact pad  770  between contact pad  770  and bottom housing  112  (or  912  if  FIG. 9 ). 
     Although aspects of the subject matter described herein have been described with reference to specific embodiments, it will be understood by those skilled in the art that various changes may be made without departing from the scope of the subject matter described herein. Accordingly, the disclosure of embodiments is intended to be illustrative of the scope of the subject matter described herein and is not intended to be limiting. It is intended that the scope of the subject matter described herein shall be limited only to the extent required by the appended claims. To one of ordinary skill in the art, it will be readily apparent that the devices and method discussed herein may be implemented in a variety of embodiments, and that the foregoing discussion of certain of these embodiments does not necessarily represent a complete description of all possible embodiments. Rather, the detailed description of the drawings, and the drawings themselves, disclose at least one preferred embodiment, and may disclose alternative embodiments. 
     All elements claimed in any particular claim are essential to the subject matter described herein and claimed in that particular claim. Consequently, replacement of one or more claimed elements constitutes reconstruction and not repair. Additionally, benefits, other advantages, and solutions to problems have been described with regard to specific embodiments. The benefits, advantages, solutions to problems, and any element or elements that may cause any benefit, advantage, or solution to occur or become more pronounced, however, are not to be construed as critical, required, or essential features or elements of any or all of the claims. 
     Moreover, embodiments and limitations disclosed herein are not dedicated to the public under the doctrine of dedication if the embodiments and/or limitations: (1) are not expressly claimed in the claims; and (2) are or are potentially equivalents of express elements and/or limitations in the claims under the doctrine of equivalents.