Patent Publication Number: US-8986017-B2

Title: Rotatable electric coupling apparatus and method

Description:
This application takes priority from U.S. provisional application No. 61/718,755 filed Oct. 26, 2012, which is incorporated herein by reference. 
    
    
     BACKGROUND 
     Pendant arm systems used in medical, commercial, and industrial environments typically support or suspend technical equipment needing electric transmissions for their operation. These electrical transmissions may be power or communications. The pendant arm systems allow users to position such technical equipment (including surgical lights, cameras, monitors/displays, yolks, and other devices) using rotational pivot joints. These rotational pivot joints need a reliable rotational electrical connection to provide the technical equipment uninterrupted electrical transmissions. The sizing limitations of the pivot joints require any internal elements to be miniature, while still being able to properly provide reliable electric transmissions. What is presented is a rotatable electric coupling apparatus small enough to secure into the pivot joint of a pendant arm system, or another similar type of apparatus, that provides and maintains a reliable and limitless rotatable electric connection. What is also presented is the method of manufacturing this rotatable electric coupling. 
     SUMMARY 
     What is presented is a rotatable electric coupling for maintaining a continuous electric connection through the pivot joint of a pendant arm system, or another similar apparatus that comprises a pivot joint. The rotatable electric coupling comprises a female connector half, a male connector half, and the female connector half corresponds with the male connector half in a way that maintains a continuous electric connection. 
     The female connector half comprises both a female connector core and a female connector housing. The female connector core comprises a female coupling part, a female core spacer, and a female core base. The female coupling part operatively contacts a corresponding male coupling part, in the male connector half, in such a way that they work in conjunction to maintain a rotational connection. The female core spacer is fastened to the female coupling part and is used to insulate the female coupling part. Both the female core spacer and said female coupling part are mounted to the female core base, which stabilizes the entire female connector core when the female connector core is inserted in the female connector half. The female core base also comprises a channel that is extended when either or both the female core spacer and female coupling part are mounted on the female core base. When the female connector core is complete, the channel laterally extends along the entire length of the female connector core. 
     The male connector half comprises the male coupling part, a male insulator element, and a male connector core. As mentioned above, the male coupling part operatively contacts the corresponding female coupling part, in such a way that they work in conjunction to maintain a rotational connection. The male insulator element is fastened to the male coupling part and insulates the male coupling part. Both the male coupling part and male insulator element are mounded on the male connector core, which has a central burrow. The male connector core stabilizes both the male coupling part and the male insulator element, when the male connector half is operatively inserted into the female connector half. 
     In certain instances, an electrical conduit can be joined to the female coupling part and the electrical conduit could also be secured within the channel using dielectric adhesive. A female end cap could also be fastened to the female connector core. The female core spacer could comprise a plurality of radial sections for fastening to the female coupling part and the female coupling part could also comprise a plurality of outward radial tabs with at least one of those outward radial tabs used for fastening to the radial section of the female core spacer. The female core base could also comprise a plurality of radial segments that are used for fastening to the female core spacer. The female coupling part could also comprise a plurality of inward radial tabs bent peripherally for operatively contacting the corresponding said male coupling part. 
     The female connector half may comprise a plurality of female coupling parts, with at least one of said female coupling parts being made from nonconductive material. The female core base could also have a plurality of channels, with each channel being extended when the female core spacer and female coupling part are mounted on the female core base. 
     In other instances, an electrical conduit could be joined to the male coupling part, a coaxial cable for transmitting an electric control signal could be inserted into the central burrow, and/or the central burrow of the male connector core could be filled with dielectric adhesive. The male coupling part could comprise an elongated divot and the male insulator element could comprise a peg, the peg is able to be interlocked with the elongated divot. The male connector core could comprise a lateral flange for securing the rotatable electric coupling to the pivot joint of a medical spring arm. The male connector half could comprise a plurality of male coupling parts with at least one of those male coupling parts made from nonconductive material. Finally, a limitless rotational connection between both the male coupling part and female coupling part could be created when the female coupling part operatively contacts the corresponding male coupling part. 
     What is also presented is a method of manufacturing the rotatable electric coupling. The method comprises assembling the male connector half, assembling the female connector half, and inserting the male connector half into the female connector half. Assembling the male connector half comprises the steps of—(1) mounting one male coupling part on the male connector core, (2) mounting one male insulator element on the male connector core, repeating steps (1) or (2) or both (1) and (2) until all male coupling parts and all male insulator elements are mounted on the male connector core. Assembling the male connector half also comprises filling the central burrow in the male connector core with dielectric adhesive. Assembling the female connector half comprises the steps of—(1) fastening one female coupling part to one female core spacer in such a way that the channel extenders are aligned, (2) stacking the fastened female coupling part and female core spacer on the female core base or stacking them on an already stacked female coupling part and female core spacer. This stacking should be done in a way that the channel of the female core base is extended by the channel extenders of the fastened female coupling parts and female core spacers. Repeating steps (1) or (2) or both (1) and (2) until all fastened female coupling parts and female core spacers are stacked on the female core base or stacked on an already stacked female coupling part and female core spacer, which, when these steps are complete, creates a female connector core. Assembling the female connector half also comprises—fastening the female end cap to the female connector core, applying dielectric adhesive throughout the channel of the female connector core, and inserting the female connector core and female end cap into a female connector housing. 
     Assembling the male connector half could also comprise—joining each male coupling part to an electrical conduit, interlocking the peg of the male insulator element with the elongated divot of the male coupling part, and/or inserting a coaxial cable into the central burrow of the male connector core. Assembling the female connector half could also comprise—joining each female coupling part to an electrical conduit, and/or fixedly securing a coaxial contact member to the female end cap. In certain instances, the male connector is only able to mount at most nine male coupling parts. The number of female coupling parts used in the manufacture of the rotatable electric coupling could be equal to the number of male coupling parts, less than the number of male coupling parts, or more than the number of male coupling parts. 
     Those skilled in the art will realize that this invention is capable of embodiments that are different from those shown and that details of the devices and methods can be changed in various manners without departing from the scope of this invention. Accordingly, the drawings and descriptions are to be regarded as including such equivalent embodiments as do not depart from the spirit and scope of this invention. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       For a more complete understanding and appreciation of this invention, and its many advantages, reference will be made to the following detailed description taken in conjunction with the accompanying drawings. 
         FIG. 1  is a side view of rotatable electric couplings installed in the pivot joints of a pendant arm system; 
         FIG. 1A  is a close up view of one of the rotatable electric couplings of  FIG. 1 ; 
         FIG. 1B  is a close up view of another of the rotatable electric couplings of  FIG. 1 ; 
         FIG. 2  is a perspective view of one of the rotatable electric couplings of  FIG. 1 ; 
         FIG. 3  is a perspective view of one of the rotatable electric couplings of  FIG. 1 , wherein the female connector half and the male connector half are partially disconnected; 
         FIG. 4  is a perspective view of one of the rotatable electric couplings of  FIG. 1 , wherein the female connector half and the male connector half are fully disconnected; 
         FIG. 5  is a side view of the male connector half of a rotatable electric coupling; 
         FIG. 5A  is a cross-sectional top view of the male connector half of  FIG. 5 , as depicted by the figure line  5 A- 5 A; 
         FIG. 6  is a cross-sectional side view of the male connector half of  FIG. 5 , as depicted by the figure line  6 - 6 ; 
         FIG. 7  is an exploded view of the male connector half of  FIG. 5 ; 
         FIG. 8  is a rear perspective view of the male connector half of  FIG. 5 ; 
         FIG. 9  is a perspective view of a male coupling part and a male insulator element separated from each other; 
         FIG. 10  is a close up cross-sectional side view of the tip of the male connector half, without a coaxial cable positioned in the central burrow of the male connector half; 
         FIG. 11  is a side view of the female connector half; 
         FIG. 12  is a cross-sectional side view of the female connector half of  FIG. 11 , as depicted by the figure line  12 - 12 ; 
         FIG. 13  is an exploded view of the female connector half of  FIG. 11 ; 
         FIG. 14  is a perspective view of a female coupling part; 
         FIG. 15  is a perspective view of the female coupling of  FIG. 14  fastened to a female core spacer, with only a portion of the female core spacer shown; 
         FIG. 16  is a perspective view of a plurality of fastened female coupling parts and female core spacers stacked on a female core base; 
         FIG. 17  is a perspective view of a female connector core fastened to a female end cap; 
         FIG. 18  is a perspective view of a male coupling part and a male insulator element being slidably mounted on a male shaft of the male connector half; 
         FIG. 19  is a perspective view of an adhesive syringe filling the central burrow of the male connector half with dielectric adhesive; and 
         FIG. 20  is a perspective view of an adhesive syringe filling the channels of the female connector half with dielectric adhesive. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to the drawings, some of the reference numerals are used to designate the same or corresponding parts through several of the embodiments and figures shown and described. Corresponding parts are denoted in different embodiments with the addition of lowercase letters. Variations of corresponding parts in form or function that are depicted in the figures are described. It will be understood that variations in the embodiments can generally be interchanged without deviating from the invention. 
     As shown in  FIGS. 1 through 1B , a rotatable electric coupling  10  is positioned in each pivot joint  12  (also known as a swivel joint) of a pendant arm system  14  used to support technical equipment  16 , such as the LCD monitor shown in  FIG. 1 . The rotatable electric coupling  10  connects electrical conduit  18  through the pendant arm system  14  to the supported attached technical equipment  16 . This connection provides the technical equipment  16  mounted on the pendant arm system  14  with stable, continuous electrical transmissions (including, but not limited to, electric power and electric communication signals). The rotatable electric coupling  10  or the pivot joint  12  may also be provided with adjustable stops (not shown) to limit the rotational movement of the pendant arm system  14  beyond certain angles. While such stops may be necessary due to the structural limitations of the pendant arm system  14 , the rotatable electric coupling  10  is designed to fully rotate 360 degrees without disrupting the continuous electric connection through the pivot joint  12 . It should be understood that the rotatable electric coupling  10  could be installed in other apparatuses that require continuous electric connections through a rotational movement of a joint. 
     As shown in  FIGS. 2 through 4 , the rotatable electric coupling  10  comprises a female connector half  20  and a corresponding male connector half  22  to maintain a continuous electric connection through individual electrical conduits  18  connected to the female connector half  20  and the male connector half  22 . The male connector half  22  is operatively inserted into an opening (discussed below) located at one end of the female connector half  20 . Once operatively inserted, the male connector half  22  and female connector half  20  are rotatable relative to each other and the male connector half  22  can be easily detached and operatively reinserted back into the female connector half  20  when needed. When the rotatable electric coupling  10  is positioned in the pivot joint of a pendant arm system  14 , the male connector half  22  remains stationary and acts as a stator element, whereas, the female connector half  20  rotates and acts as a rotor element. Properly inserting the male connector half  22  into the female connector half  20  also completes the electrical connection for each electrical conduit  18  through the entire rotatable electric coupling  10 . 
     The male connector half  22  comprises two lateral flanges  40  each comprising a notch  42 . Referring back to  FIGS. 1 through 1B , it can be seen that the flanges  40  and notches  42  position and secure the rotatable electric coupling  10  into the pivot joint of the pendant arm system  14 . Typically, the pendant arm system  14  or pivot joint  12  has some kind of corresponding extrusions (not shown) that interlock into each notch  42  to hold the rotatable electric coupling  10  in place. A joining mechanism (not shown) could also be inserted through each notch  36  and into the pendant arm system  14  to hold the rotatable electric coupling  10  in place. 
     As can be seen in  FIGS. 1 through 1B , the rotatable electric coupling  10  functions in any orientation with the electric transmissions going first through either the male connector half  22  or the female connector half  20 . In some embodiments of the rotatable electric coupling  10  (not shown), ball bearings could be used to assist the rotation of the rotatable electric coupling  10 , but this is not required in the embodiments shown. When the pendant arm system  14  is manufactured, the male connector half  22  may be installed into one half of the pivot joint  12  and the female connector half  20  may be installed into the other half of the pivot joint  12 . When two halves of the pivot joints  12  are assembled, the male connector part  22  should be simply inserted into the female connector half  20  to complete the pivot joint  12 , as discussed above. So long as the proper connections with the electrical conduit  18  are established, no further electric connections need to be made within the pivot joint  12 . 
     Referring to  FIGS. 5 through 9 , the male connector half  22  comprises a male connector core  24 , a male support  26 , a tip  34 , and a central burrow  28  running centrally through the entire male connector core  24 . The male connector half  22  also comprises a plurality of metallic electrically conductive male coupling parts  30  and nonconductive male insulator elements  32  laterally mounted along the outside of the male connector core  24  between the male support  26  and the tip  34 . When operatively inserted into the female connector half (not shown), the male coupling parts  30  are correctly positioned to contact a metallic electrically conductive corresponding female coupling part (as discussed below) in a way that maintains a limitless rotational electrical connection. The limitless rotational electrical connection is one in which the male coupling parts  30  and female coupling parts are connected in such a way that each can rotate 360 degrees, or beyond, relative to each other without causing any disruption in their electrical connection. 
     The male connector core  24  stabilizes and correctly positions the male coupling parts  30  and male insulator elements  32 , when the male connector half  22  is operatively inserted into the female connector half  20 . The male connector core  24  is generally made from injection molded nonconductive polymer plastic material, but may be made from any nonconductive material able to stabilize both the male coupling parts  30  and male insulator elements  32  as well as be formed into a similar shape. 
     The male connector core  24  generally has a tubular shape with a circular cross-section (not shown). The cross-section of the tip  34  is wider in diameter than the cross-section of the male connector core  24 . The mounted male coupling parts  30  and mounted male insulator elements  32  press against one side of the tip  34 , helping to maintain their position on the male connector core  24 . A tip chamfer  35  assists in guiding the male connector half  22  into the female connector half  20  (as shown in  FIGS. 2-4 ). The male connector core  24  also has two elongated openings  36  oriented opposite each other that run laterally down the length of the male connector core  24 . The elongated openings  36  allow for the electrical conduit  18  joined to each male coupling part  30  to go into the central burrow  28  of the male connector half  22 . The male shaft support  26  provides a base for the male connector core  24 . 
     In the embodiment shown in  FIGS. 4 through 9 , the male connector half  22  comprises nine male coupling parts  30  and nine male insulator elements  32 . As best shown by comparing  FIGS. 9 and 10 , each male coupling part  30  is substantially ring shaped except an elongated divot  41  and a minor recessed area both located on its interior surface  42 . The elongated divot  41  is located opposite to the recessed area where the electrical conduit  18  is joined to the male coupling part  30 . The electrical conduit  18  is soldered to the male coupling part  30  and this recessed area is shaped to allow that soldering to join to the male coupling part  30  without unduly spreading along the entire interior surface  42 . It should be understood that any method of joining the electrical conduit  18  to the male coupling part  30  that allows for an electrical connection between the electrical conduit  18  and male coupling part  30  may work. It may also be desirable to identify each electrical conduit  18  by uniquely coloring the coating on each electrical conduit  18 . The exterior surface  43  of the male coupling part  30  has a high polish finish to smooth this surface and facilitate the limitless rotational electrical connection. It should be understood, that smoothing the exterior surface  43  may be done in other ways, such as, but not limited to, adding an oil based lube to the outer surface  43 . 
     Each male insulator element  32  fastens to its corresponding male coupling part  30  and insulates its corresponding male coupling part  30  by keeping the electricity flowing through the male coupling part from flowing into other male coupling parts  30  mounted on the male connector core  24 . Typically the male insulator elements  32  are made from nonconductive injection molded polymer plastic material, but any nonconductive material may work. The male insulator elements  32  are also used to laterally space each male coupling part  30  apart from the next nearest male coupling part  30 , ensuring each male coupling part  30  is correctly positioned along the male connector core  24 . Each male insulator element  32  comprises a peg  44  that is shaped to compliment the elongated divot  41  of the corresponding male coupling part  30 . To fasten the male insulator element  32  to the male coupling part  30 , the peg  44  slides into and interlocks with the elongated divot  41 . 
     In certain applications, it may be beneficial for at least one male coupling part  30  laterally mounted along the male connector core  24  to be made from nonconductive material, otherwise known as a “blank male coupling part.” This configuration allows for there to be less than nine conductive male coupling parts  30  to be mounted along the male connector core  24  without having to change the length or shape of the male connector core  24 . If needed, this configuration also allows for there to be fewer conductive male coupling parts  30  than corresponding conductive female coupling parts, discussed below. Such nonconductive male coupling parts  30  may be made out of the same injection molded polymer plastic material that the male insulator element  32  and/or the male connector core  24  are made out of, but any nonconductive material may work. 
     As briefly discussed above, the male connector core  24  comprises a central burrow  28  that runs laterally through the center of the male connector core  24  and creates openings on both of its ends. A coaxial cable  46  is insertable into the central burrow  28  such that a male or plug-type connector  49  of the coaxial cable  46  protrudes from the tip  34 . The central burrow has a large enough diameter to not only allow the coaxial cable  46  and each electrical conduit  18  to be strewn through it, but also to allow dielectric adhesive (as shown and discussed with respect to  FIG. 19 , below) to be injected into it. This dielectric adhesive (discussed below) fills in any unused space within the central burrow and, after solidifying, provides surrounding structure around the coaxial cable  46  and each electrical conduit  18  so that each element is completely stationary when the rotatable electric coupling is fully manufactured. The dielectric adhesive also provides electrical insulation within the male connector core  24 , further ensuring the electric transmissions traveling through the coaxial cable  46  will not interfere with the electric transmissions travelling through the nearby electrical conduits  18  and the electric transmissions traveling through the electrical conduits  18  will not interfere with the electric transmissions in any other nearby electrical conduit  18 . 
     The coaxial cable  46  is used for transmitting an electric control signal (i.e. a form of electric transmissions) being supplied to the technical equipment, which are, for example, connecting radio transmitters and receivers, computer network (Internet) connections, and cable television signals, etc. In this embodiment, the coaxial cable  46  is a standard SMB connector capable of electric transmissions up to 10 Ghz. It should be understood, any coaxial cable  46  able to properly transmit an electric control signal allowing the technical equipment  16  to function may work. It should also be understood that other types of cable connectors could be used to instead of the coaxial cable  46 , such as pneumatic or optical connectors. 
     When the male coupling parts  30  and corresponding male insulator elements  32  are properly mounted on the male connector core  24 , the electric transmissions through each male coupling part  30  does not necessarily have to be the same as the electric transmissions through any other male coupling part  30  on the on the male connector core  23 . Each male coupling part  30  is intended to transmit high definition component (RGB) video signals, audio signals, control signals, and/or DC or AC power, but there may be other types of electric transmissions not discussed herein. Since the number and combination of the male coupling parts  30  and corresponding male insulator elements  32  can be mounted on the male connector core  24  in different ways, the combination of electric transmissions through the male coupling parts  30  is flexible and can be modified depending on the specific needed use of the pendant arm system  14 . 
     As shown in  FIGS. 11 through 13 , the female connector half  20  comprises a female connector core  52  and a female connector housing  54 . The female connector housing  54  is generally made from nonconductive injection molded polymer plastic material, but could be made from any material suitable for housing the female connector core  52  (e.g. metallic material). 
     The female connector housing  54  comprises an outer housing  55  that has a fastening hole  57 . Referring back to  FIGS. 1-1B , the outer housing  55  helps to properly position the rotatable electric coupling  10  within the pivot joint  12 . The fastening hole  57  used in conjunction with a fastener (not shown) that affixes the female connector half  20  in the respective half of the pivot joint  12 . Based on the specific dimensions of the pivot joint  12 , the position of the outer housing  55  may be customized to any location along the female connector housing  54 . 
     As shown in  FIG. 13 , the female connector core  52  comprises a plurality of electrically conductive female coupling parts  56 , a plurality of nonconductive female core spacers  58 , a nonconductive female core base  60 , and a nonconductive female end cap  62 . This embodiment of the female connector half  20  comprises nine female coupling parts  56  and nine female core spacers  58 . Each female coupling part  56  fastens to a corresponding female core spacer  58 , creating nine pairs of female coupling parts  56  and female core spacers  58  fastened together. As discussed above, each female coupling part  56  operatively contacts a corresponding male coupling part to maintain the limitless rotational electrical connection. The female core spacers  58 , female core base  60 , and female end cap  62  are each generally made from nonconductive injection molded polymer plastic material, but any nonconductive material may work for these components. 
     Referring to  FIG. 14 , Each female coupling part  56  is made from conductive metallic material so that electric transmissions may pass through when needed. In this embodiment, each female coupling part  56  also has a silver plated smooth finish to facilitate the limitless rotational electrical connection. Each female coupling part  56  comprises a plurality of outward radial tabs  70  and a plurality of inward radial tabs  72 . The outward radial tabs  70  extend outwardly from the central axis  76  of the female coupling part  56 . Each female coupling part  56  comprises nine independent outward radial tabs  70 . Each outward radial tab  70  comprises an opening  74  which has a circular cross-section. It should be understood that the female coupling parts  56  could be made from material that is not metallic, so long as the material is electrically conductive. The plurality of inward radial tabs  72  extend inwardly towards the central axis  76  of the female coupling part  56  and are bent peripherally from the female coupling part  56  in a rounded manner. Each female coupling part  56  comprises nine independent inward radial tabs  74 . The inward radial tabs  74  work in conjunction to form an circular-shaped perimeter with a circumference just larger than the circumference of the exterior surface of its corresponding male coupling part. 
     As best seen by comparing  FIGS. 13 and 15 , each female core spacer  58  comprises a plurality of radial sections  64 , which extend outwardly from the central axis  76  of the female core spacer  58 . Each female core spacer  58  comprises eight independent radial sections  64 . Each radial section  64  itself comprises a projection  66 , having a circular cross-section, which extends peripherally from the radial section  64  and parallel to the central axis  76 . The projections  66  are sized to fit through the openings  74  of the outward radial tabs  70  in the female coupling part  56 . On the side of the radial section  64  opposite the one comprising the projection  66 , the radial section comprises a depression  68 , having a circular cross-section, which goes into the radial section  64 . The radial sections  64 , in conjunction with each other, are used to fasten the female core spacer  58  to the female coupling part  56 , as discussed in detail below. 
     Referring to  FIG. 15 , to create a fastened pair of female coupling parts  56  and female core spacers  58 , the projection  66  on the female core spacer  58  is inserted into and extends beyond the opening  74  on the female coupling part  56 . As best seen in  FIGS. 16 and 17 , each pair of female coupling parts  56  and female core spacers  58  fastened together can be stacked onto another pair of these parts. The projection  66  is long enough that after being inserted into the opening  74 , the projection  66  can be inserted into the depression  68  on a corresponding female core spacer  58 . The opening  74  on each outward radial tab  70  of each female coupling part  56  compliments the projection  66  on each radial section  64  of the other female core spacers  58 . The depression  68  on each radial section  64  of each corresponding female core spacer  58  compliments the projection  66  on each radial section  64  of the other female core spacer  58 . A snug fit is maintained between each of the projection  66 , opening  74 , and depression  68  when the female coupling part  56 , female core spacer  58 , and any other corresponding female core spacer  58  are stacked together. 
     The stack of female coupling parts  56  and female core spacers  58  is mounted on the female core base  60 . The female core base  60  stabilizes the entire female connector core  52  when the female connector core  52  is in the female connector half  20 . The female core base  60  comprises a plurality of radial segments  78 , which extend outwardly from the central axis  76  of the female core base  60 . The radial segments  78  are identical in nature to the radial sections  64  of the female core spacer  58 . Each radial segment  78  comprises a plurality of concavings  80 , having a circular cross-section. The concavings  80  are identical in nature to the depressions  68  of the radial sections  64 , discussed above. 
     To properly stack the pairs of female coupling parts  56  and female core spacers  58  fastened together, a first pair of a female coupling part  56  and a female core spacer  58  is mounted on the female core base  60 . To mount the first pair of female coupling parts  56  and female core spacers  58  fastened together on to the female core base  60 , the exposed portion of the projections  66 , which have been inserted into and extended through the openings  74 , are inserted into the concavings  80  on the female core base  60 . Then a second pair of a female coupling part  56  and a female core spacer  58  is stacked onto the first pair, and each subsequent pair is stacked respectively from there on. When the required number of pairs of female coupling parts  56  and female core spacers  58  fastened together are mounted and stacked onto the female core base  60 , the ring-shaped female end cap  62  is fastened (as described below) to the final pair of female coupling parts  56  and female core spacers  58  fastened to complete the female connector core  52 . 
     The ring-shaped female end cap  62  is fastened to the female connector core  52  by fastening to the final pair of female coupling parts  56  and female core spacers  58  fastened together in the stack on the female core base  60 . On one side, the female end cap  62  has a plurality of protrusions (not shown). Each protrusion is identical in nature to each of the projections  66  of each female core spacer  58  and each protrusion extends peripherally from the female end cap  62 . The protrusions on the female end cap  62  insert into the depressions  68  of the final female core spacer  58  at one end of the female connector core  52 . The female end cap  62  fastens to the female connector core  52 , in the same manner each female core spacer  58  fastens to a corresponding female core spacer  58 , discussed above. On the side that does not fasten to the female connector core  52 , the female end cap  62  comprises a cap chamfer  63 , which corresponds to the tip chamfer on the male connector core. The cap chamfer  63  assists in directing the male connector half  22  centrally into the female connector half, as discussed below 
     Referring back to  FIGS. 11-13 , a coaxial contact member  83  is fixedly secured to the female connector core  52  through the center and at the end opposite the one fastened to the female end cap  62 . In this embodiment, the coaxial contact member  83  is fixedly secured using dielectric adhesive. The coaxial contact member  83  has a central-docking port  85 , which is centrally located in the female connector half  20  when the coaxial contact member  83  is fixedly secured to the female connector core  52 . As shown in  FIGS. 2-4 , the central-docking port  85  allows the plug-type connector  49  of the coaxial cable  46  on the male connector half  52  to slidably mount into it. The coaxial contact member  83  functions as an extension of the coaxial cable  46  that protrudes through the male connector half  22 . When the plug-type connector  49  is slidably mounted into the central-docking port  85 , any electric transmissions first traveling through the coaxial cable  46  are extended through the coaxial contact member  83 . If the rotatable electric coupling  10  is oriented in the opposite manner within the pendant arm system  14 , any electric transmissions first traveling through the coaxial contact member  83  are extended through coaxial cable  46 . 
     Referring back to  FIG. 17 , the female core base  60  comprises a plurality of channels  86 . Each channel  86  extends laterally lengthwise along the female core base  60  between two radial segments  78 . In this embodiment, the female core base  60  comprises nine channels  86  with each channel  86  being straight from end to end. It will be understood, the female core base  60  could comprise fewer than nine channels  86  and each channel  86  may not be straight, nor do the channels  86  have to each have the same overall shape from end to end. It will be understood that every time a pair of female coupling parts  56  and female core spacers  58  fastened together is fastened to the female core base  60 , the space between the outward radial tabs  70  of each female coupling part  56  and the radial sections  64  in the female core spacers  58  act as channel extenders that extend the channels  86  further along the female connector core  52 . When the female connector core  52  is complete, except for a missing portion of the walls on each side of the channel  86 , discussed below, each channel  86  extends laterally the length of the entire female connector core  52 . 
     As mentioned above, in this embodiment, each female coupling part  56  comprises nine outward radial tabs  70  and each female core spacer  58  comprises eight radial sections  64 . As best shown in  FIGS. 16 and 17 , the female core spacers  58  are constructed such that when one female core spacer  58  and one female coupling part  56  are paired together, one of the radial tabs  70  is free standing and not fastened to a radial section  64 . The female core spacers  58  are also constructed such that when a pair of female coupling parts  56  and female core spacers  58  fastened together is stacked against another pair, one radial tab  70  extends outwardly in the center of an axial gap  90  created by these missing radial sections  64 . When the female connector core  52  is complete, each axial gap  90  forms a missing portion of the walls on each side of the channel  86  with the radial tab  70  free standing and extending from the middle of this axial gap  90 . These axial gaps  90  occur at different lateral locations, creating an offset pattern, along the body of the female connector core  52  for each channel  86 . 
     The free standing radial tab  70  of the female coupling part  56  is joined to an electrical conduit  18 . Having the axial gaps  90  occurring at different locations allow each electrical conduit  90  to be positioned in its own respective channel  86 . Once positioned in the channel  86 , the electrical conduit  18  travels centrally along length of the channel  86  and is secured within the channel  86  with dielectric adhesive  94 . The dielectric adhesive  94  is spread throughout the entirety of each channel  86 , throughout each axial gap  90 , and is used to secure the female connector housing  54  in place on the female connector half  20 . This dielectric adhesive  94  fills in any unused space within each channel  86  and each axial gap  90 . After the dielectric adhesive  94  has solidified, it provides surrounding structure around each electrical conduit  18  in the respective channel  86  so that electrical conduit  18  remains completely stationary. The dielectric adhesive  94  also provides electrical insulation within in the respective channel  86  and axial gap  90 , further ensuring all electric transmissions through the electrical conduit  18  will not interfere with the electric transmissions through the electrical conduits  18  in the nearby adjacent channels  86 . The dielectric adhesive  94  also ensures the electrical conduit  18  remains joined to the female coupling part  56 . The dielectric adhesive  94  is the same type of dielectric adhesive used to fill the male connector half, as discussed above. 
     Each female core spacer  58  is thick enough to insulate its corresponding female coupling part  56 . Electric transmissions through one female coupling part  56  will not pass through to another female coupling part  56  in the female connector core  52 . Typically each female core spacer  58  is made from nonconductive injection molded polymer plastic material, but any nonconductive material may work. 
     In certain applications, it may be beneficial for the female connector core  52  to comprise at least one female coupling part  56  made from nonconductive material, otherwise known as a “blank female coupling part.” This configuration allows for there to be less than nine conductive female coupling parts  56  stacked on the female core base  60  without having to change the length, shape, or channels of the female connector core  52 . This configuration also allows for there to be fewer conductive female coupling parts  56  than corresponding conductive male coupling parts, if needed. The nonconductive material constructing this female coupling part  56  may be the same injection molded polymer plastic material that constructs the female core spacers  58  and/or the female core base  60 , but any nonconductive material may work. 
     When the female connector core  52  is complete, the electric transmissions through each female coupling part  56  does not necessarily have to be the same as the electric transmissions through any other female coupling part  56  e on the female connector core  52 . However, the electric transmissions running from an individual male coupling part must be the same transmissions through the corresponding female coupling part  56 . As discussed with the male coupling parts on the male connector core above, each female coupling part  56  is able to transmit high definition component (RGB) video signals, audio signals, control signals, and/or DC or AC power, but there may be other types of electric transmissions that could travel through the female coupling part  56  not discussed herein. Since the number and combination of the female coupling parts  56  and corresponding female core spacers  58  may vary, the combination of electric transmissions through the female coupling parts  56  is flexible and can be changed depending on the specific use of the pendant arm system  14 . As mentioned above, it may also be desirable to identify each electrical conduit  18  by uniquely coloring the coating on each electrical conduit  18 . 
     Referring back to  FIGS. 2 through 4 , and  12 , when the male connector half  22  is operatively inserted into the female connector half  20 , the tip chamfer  35 , cap chamfer  63 , and the circular-shaped perimeter created by the inward radial tabs  72  of the female coupling part  56  all direct the male connector core  24  towards the center of the female connector half  20 . This ensures the male connector half  22  is properly inserted into the female connector half  20 . Proper insertion of the male connector half  22  also ensures that each female coupling part  56  is operatively contacted to their corresponding male coupling part  30 , creating the limitless rotational electrical connection between both the male coupling part  30  and female coupling part  56 . This limitless rotational electrical connection is efficient, sturdy, reliable, and durable. 
     As shown in  FIGS. 18 through 20 , the method of manufacturing the rotatable electric coupling is unique in itself. The male connector half or the female connector half are assembled separately, and it does not matter which connector half is assembled before the other. Each male coupling part  30  and each female coupling part  56  is joined to its own respective electrical conduit  18  prior to the assembly of either the male connector half  22  and female connector half  20 . It should be understood, the electrical conduits  18  could be joined to their respective male coupling part  30  and female coupling part  56  at various other times during the manufacture of the rotatable electric coupling. 
     The manufacture of the male connector half is illustrated in  FIGS. 18 and 19 . In this embodiment, the male connector half  20  is assembled as follows: 1) one male coupling part  30  is mounted on the male connector core  24 ; and 2) one male insulator element  32  is mounted on the male connector core  24 . These steps should be repeated until all required male coupling parts  30  and all male insulator elements  32  are mounted on the male connector core  23 . The male insulator element  32  and male coupling part  30  could also be fastened together before being mounted to the male connector core  23  and then fastened pair both mounted on the male connector core  23  together. In the embodiment shown, nine male coupling parts  30  are mounted on the male connector core  23 . 
     Once all male coupling parts  30  and all male insulator elements  32  are mounted on the male connector core  23 , the coaxial cable  46  is inserted into the central burrow  28  in the male connector core  23  such that a male or plug-type connector  49  of the coaxial cable  46  protrudes from the tip  34 . The central burrow  28  is then filled with dielectric adhesive using an adhesive syringe  96 . When the central burrow  28  is filled and the dielectric adhesive has solidified, manufacture of the male connector half  22  is complete. 
     Manufacture of the female connector half  20  is shown in  FIG. 20 . In this embodiment, the female connector half  20  is assembled as follows: 1) one female coupling part  56  is fastened to one female core spacer  58  in such a way that the space between the outward radial tabs  70  of each female coupling part  56  and the radial sections  64  in the female core spacers  58  align to act as channel extenders; and 2) the fastened female coupling part  56  and female core spacer  58  are stacked on the female core base  60  in such a way that the channel  86  of the female core base  60  is extended by the channel extenders of the fastened female coupling parts  56  and female core spacers  58 . Fastening one female coupling part  56  to one female core spacer  58  is discussed in more detail above. If the fastened female coupling part  56  and female core spacer  58  pair are already stacked on female core base  60 , then step two actually comprises—the fastened female coupling part  56  and female core spacer  58  are stacked the previously and already stacked female coupling part  56  and female core spacer  58  pair, in such a way that the channel  86  of the female core base  60  is extended by the channel extenders of the fastened female coupling parts  56  and female core spacers  58 . These steps should be repeated until all fastened female coupling parts  56  and all female core spacers  58  are stacked on the female core base  60 , or on an already stacked female coupling part  56  and female core spacer  58 . 
     After the required number of stacked female connector core  52  is created, a female end cap  62  is fastened to create a complete female connector core  52 . Then dielectric adhesive  94  is applied into and throughout each of the channels  86  laterally extending along the female connector core  52 , within each axial gap  90 , and up to the female end cap  62 . The dielectric adhesive  94  is used to fixedly secure the coaxial contact member  83  to the female end cap  62 . Once the dielectric adhesive  94  has solidified, the coaxial contact member  83  is properly fixedly secured to the female end cap  62  and remains completely stationary. 
     The completed female connector core  52  is slidably inserted into the female connector housing  54 . Although not necessary, it is preferable to slidably insert the female connector core  52  and female end cap  62  into the female connector housing  54  before the dielectric adhesive  94  has solidified, so that the dielectric adhesive  94  fully adheres to the female connector housing. Finally, the position of the outer housing  55  is determined along the female connector housing  54  and the outer housing is  55  is affixed to the female connector housing  55 . It should be understood, in the embodiment shown in  FIG. 20 , for the female connector core  52  to properly fit within the female connector housing, the female connector core  52  can at most mount nine female coupling parts  56  and nine female core spacers  58 . 
     To complete this embodiment of the method of manufacture, the male connector half  22  is inserted directly into the female connector half  20 , which completes the rotatable electric coupling  10 . Inserting the male connector half  22  into the female connector half  20  is explained in more detail above. It should be understood, when the method of manufacture of the rotatable electric coupling  10  is complete, the number of female coupling parts  56  used may be equal to the number of male coupling parts  30 , the number of female coupling parts  56  used may be more than the number of male coupling parts  30 , or the number of female coupling parts  56  used may be less than the number of male coupling parts  30 . It should also be understood that this method of manufacture is applied to the embodiment of the rotatable electric coupling disclosed and discussed above, but it may also be applied to different embodiments of the rotatable electric coupling. 
     This invention has been described with reference to several preferred embodiments. Many modifications and alterations will occur to others upon reading and understanding the preceding specification. It is intended that the invention be construed as including all such alterations and modifications in so far as they come within the scope of the appended claims or the equivalents of these claims.