Abstract:
Methods and devices for connecting a current source to a target storage device via a transmission cable extendable and/or retractable via a conduit that may be repositioned.

Description:
[0001]    This application is a continuation of International Application No. PCT/US2009/030945 filed Jan. 13, 2009, which claims the benefit of U.S. Provisional Patent Application Ser. No. 61/010,869, filed Jan. 14, 2008, which is hereby incorporated herein by reference in their entirety for all purposes. 
     
    
     TECHNICAL FIELD 
       [0002]    The invention, in its several embodiments, pertains generally to methods and devices for electrical transmission via a transmission cable extendable and retractable via a conduit that may be repositioned. 
       BACKGROUND 
       [0003]    U.S. Pat. No. 7,256,516 and U.S. Pat. No. 5,306,999 disclose electric vehicle (EV) charging stations. EV charging stations in the state of the art typically emulate conventional gas station fueling characteristics and accordingly may be described generally as segmented into three main systems analogous to a gasoline station pump. The analogous segments include: (a) a base unit for managing the fuel supply, in this case electricity from the electric utility system; (b) a fuel transfer hose, or in the EV case a transmission cable to carry the flow of electricity to the EV; and (c) a connector from the transmission cable to the EV itself. 
       SUMMARY 
       [0004]    The invention, in its several embodiments, comprises methods and devices for connecting a current source to a target storage device via a transmission cable extendable and retractable via a conduit that may be repositioned. For example, a battery charging device embodiment of the present invention may comprise: a conduit segment configured to receive an extending transmission cable; the transmission cable connectable, e.g., switchably, and/or directly, or in some fashion the transmission cable may be placed in an electrical communication with a current source; and a transmission cable drive mechanism configured to extend the transmission cable into the conduit segment. An exemplary embodiment may also include a housing that comprises the transmission cable connectable to the current source and a transmission cable drive mechanism configured to extend the transmission cable into the conduit segment. The transmission cable of some battery charging device embodiments may be disposed about at least one drive wheel aligned to extend the transmission cable in a direction away from the housing and into the conduit segment. The transmission cable drive mechanism of some battery charging device embodiments may comprise a tow wire and drive pulley. The transmission cable drive mechanism of some battery charging device embodiments may be further configured to retract the transmission cable from the conduit segment. Some battery charging device embodiments may further comprise a conduit assembly comprising the conduit segment and a handle-connector assembly comprising a transmission cable connector and a target port connector and for some of the embodiments, the transmission cable drive mechanism may comprise a partial vacuum generator effecting a partial vacuum, the partial vacuum effected proximate to the handle-connector assembly. Some battery charging device embodiments may have a transmission cable drive mechanism comprising a pressure differential generator effecting a pressure differential, the pressure differential having a volume of lower pressure effected proximate to the handle-connector assembly. Some battery charging device embodiments may air cool the transmission cable by blowing air within the conduit segment. Some battery charging device embodiments may further comprise a transmission cable comprised of at least two conductive cables, e.g., two, three or four conductive cables. Some battery charging device embodiments may further comprise a coating having a low coefficient of sliding friction interposed between the transmission cable and the conduit segment. Some battery charging device embodiments may further comprise a transmission cable drive mechanism where a first wheel opposes a second wheel and where at least one of: (a) the first wheel; and (b) the second wheel is a drive wheel, and where at least one of the first wheel and the second wheel may retractably engage the transmission cable via active mechanisms, such as via the powering of a solenoid, e.g., when extending or holding in place the transmission cable due to pulley rotation or non-rotation respectively. 
         [0005]    Embodiments of the present invention include methods of charging a target storage device. For example, a method of charging a target storage device may comprise the steps of: (a) engaging a target storage device electrical receptacle with the target port connector of a conduit assembly comprising a conduit segment; (b) extending a transmission cable, within the conduit segment and away from a conduit assembly support structure, by a transmission cable drive mechanism, to engage the target port connector via the conduit segment; and (c) initiating current flow to the target storage device from a current source via the transmission cable. For some of the method embodiments, the transmission cable may be disposed about at least one drive wheel aligned to extend the transmission cable in a direction away from the housing and into the conduit segment. For some of the method embodiments, the transmission cable drive mechanism may comprise a tow wire and drive pulley. The exemplary methods of charging a target storage device may further comprise the steps of: (d) stopping current flow to the target storage device from the current source via the transmission cable and (e) retracting the transmission cable from the conduit segment. Some of the method embodiments may further comprise air cooling the transmission cable within the conduit segment. The exemplary methods of charging a target storage device may further comprise a coating having a low coefficient of sliding friction interposed between the transmission cable and the conduit segment. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]    Embodiments of the present invention are illustrated by way of example and not limitation in the figures of the accompanying drawings, and in which: 
           [0007]      FIG. 1  is a perspective view of an embodiment of the present invention; 
           [0008]      FIG. 2  is a side view of an embodiment of the present invention; 
           [0009]      FIG. 3  is a transverse, cross-sectional view of a conduit segment of an embodiment of the present invention; 
           [0010]      FIG. 4  is a side cross-sectional view of a handle-connector assembly embodiment of the present invention; 
           [0011]      FIGS. 5A and 5B  are side views of another embodiment of the present invention; 
           [0012]      FIGS. 5C and 5D  are side views of exemplary drive wheel embodiments disengaging and engaging a transmission cable; 
           [0013]      FIG. 6  is a transverse, cross-sectional view of a conduit segment of another embodiment of the present invention; and 
           [0014]      FIG. 7  is a transverse, cross-sectional view of a conduit segment of another embodiment of the present invention; 
       
    
    
     DETAILED DESCRIPTION 
       [0015]    Reference is made to the drawings that illustrate exemplary embodiments of the present invention.  FIG. 1  illustrates a charging station  100  comprising a housing  110  having a user interface  112 , such as a display that may be a touch screen, and the user interface  112  may include one or more buttons. The housing  110  may further comprise as a conduit assembly support structure both an exit port  114  and docking port  116  for a charging conduit assembly  120 . In some embodiments, the conduit support structure may be disposed outside of the housing  110  and include a mounting for a transmission cable  160  and/or a transmission drive mechanism. The exemplary charging conduit assembly  120  is shown comprising a conduit segment  122  having a portion proximal  121  to the housing  110 , and, disposed at a distal portion  123 , a handle-connector assembly  124 . The handle-connector assembly  124  is configured to both receive an extended transmission cable  160  and engage a target charging port (not shown), such as an EV charging receptacle. The housing  110  is shown enclosing a processor housing  130  and a power converter housing  140  that may house a current source. The transmission cable  160  may be extended into the conduit segment  122  by a transmission cable drive mechanism. The power converter housing  140  is shown supporting a reel  150 , and  FIG. 1  illustrates an optional exemplary transmission cable drive mechanism as the reel  150  that may be operating as a drive wheel for extension and/or for cable retraction, about which is wound a transmission cable  160  and, in this example, the transmission cable  160  connects with the housed converter unit via an electrical interface (not shown) that may be within the reel hub. Also shown is a pair of opposing wheels, pulleys  170 , or rollers, each having a pair of circumferential troughs for guiding the transmission cable  160 .  FIG. 1  also illustrates an optional exemplary transmission cable drive mechanism where one or both of the opposing wheels, pulleys  170 , or rollers may be configured to be powered as one or more drive wheels for extending the transmission cable and/or retracting the transmission cable. A guiding element  180  having an aperture for receiving the transmission cable  160  may be mounted to the power converter housing  140 . The exemplary embodiment of  FIG. 1  may be applied to the charging of an electrical vehicle where the transmission cable, particularly the conduction core is sized for a current flow of greater than 400 amps. 
         [0016]      FIG. 2  illustrates a portion of the exemplary charging station  100  in a side view with a side panel of the housing  110  removed, a side panel of the exit port  114  removed, a portion of the conduit segment  122  shown in longitudinal cut-away, and the reel  150  cap is removed. In this example, at least one of: the reel  150 , upper wheel or pulley  271 , and/or lower wheel or pulley  272  may be powered to rotate the reel clockwise  211  and counterclockwise  212 . The pair of transmission cables  160  travel  290  within the conduit segment  122  according to the direction of rotation of the at least one drive wheel. The transmission cable  160  may generally comprise an electrically insulative material, and/or a material that exhibits a low sliding friction coefficient about conductive cables, but a distal portion  261  of each of the transmission cables may be not be insulated. An inner port seal  220  is shown in cut-away having an aperture receiving the pair of transmission cables  160 . The inner port seal  220  may be integral to the proximal end of the conduit segment  122 . The aperture of the inner port seal  220  may be insulative material shielding the distal portion  261  of each of the transmission cables when in a state of full operational retraction. A transverse cut  3  of the conduit segment  122  containing the transmission cable  160  is shown in  FIG. 3 . 
         [0017]      FIG. 3  illustrates an exemplary cable and conduit arrangement as a cross-sectional view of the conduit segment  122  containing a portion of the transmission cable  160  that comprises two major channels  311 ,  312  and two minor channels  321 ,  322 . The inner wall of the conduit segment and the outer wall of the transmission cable may be coated or have applied to them a material exhibiting a low sliding friction coefficient. The inner walls of the two major channels  311 ,  312 , may be coated or have applied, e.g., as a layer or a wrap, to them a material exhibiting a low sliding friction coefficient. In this example, a first conductive cable  331  and a second conductive cable  332  together comprise a conductive core of the transmission cable  160 . The first conductive cable  331  may be encased in an electrically insulative material  341 , and/or a material that exhibits a low sliding friction coefficient. Likewise, the second conductive cable  332  may be encased in an electrically insulative material  342 , and/or a material that exhibits a low sliding friction coefficient. The outer wall of the cable encasing material  341 ,  342  may not fully contact each of the inner walls of the two major channels  311 ,  312 , thereby allowing an air volume to be disposed between a portion of a major channel inner wall  361  and a portion of an encasing material outer wall  362 . 
         [0018]    During the charging process, the transmission cables may heat due to resistive effects. The conductive cables  331 ,  332  may be characterized for their resistivity as a function of temperature. The temperature of the conductive cables  331 ,  332  may be monitored by reading the voltage from one end of the cable to the other. Based on the instant current, the resistance of the cable may be derived, e.g., R=V/I. From the derived resistance, the temperature of the conductive cables  331 ,  332  may be inferred. The inferred temperature may be used in determining whether the charging is occurring within acceptably safe regions of cable temperature. To enhance the duration of a safe charging interval, active cooling of the conductive cables, the transmission cable, and/or the conduit segment may be effected by providing a conduit segment having an inner diameter larger than the outer diameter of each of the conductive cables and forcing air through the resulting volume in a direction from the charger housing to the connector end, or the reverse of that direction. The target device being charged, e.g., an electric vehicle, may have a mating receptacle, i.e., a target port, that has a mating hole that may be aligned with an exit air flow hole of the handle-connector assembly. Such an alignment may provide for the cooling of both the conductive cables  331 ,  332  and the target port, e.g., an EV receptacle. Accordingly, a blower (not shown) may be disposed within the housing  110 , a housing  110  having an air intake duct, and the blower may be oriented to move the volume of air from the proximal portion of the conduit segment  121  toward the distal portion of the conduit segment  123  ( FIG. 1 ). One of the exemplary minor channels  321  may house an electrical pilot wire  351  that may be used to verify a closed electrical circuit prior to powering the converter to drive current through the transmission cable  160 . The other of the exemplary minor channels  322  may house a ground wire  352  and the other of the exemplary minor channels  322 , or an additional minor channel, may house a communication cable (not shown) to allow for communication between a processor (not shown) enclosed by the processor housing  130  and the handle-connector assembly  124  ( FIG. 1 ). These or additional minor channels may be used as conduits for tow cable embodiments of a transmission cable drive mechanism. 
         [0019]      FIG. 4  illustrates an exemplary electrical interface at the distal end  123  of the conduit segment particularly between a handle-connector assembly  424  and the pair of conductive cables  331 ,  332 . This example shows a first electrical connector  410  having a socket portion  411  for receiving the distal end of the first conductive cable  331  and a second electrical connector  420  having a socket portion  421  for receiving the distal end of the second conductive cable  332 . 
         [0020]    Returning to  FIGS. 1 and 2 , the electrical interface  251  within the reel hub may provide an electrical connection with the converter-base unit source end of the transmission cable  160  as a rotary, brush-type connection. For power and amp levels higher than those practically supported by brush-type connectors, and/or for longer wearing connections, the transmission cable  160 , particularly the conductive cables  331 ,  332 , may be solidly attached to the source end. Embodiments having fixed attachments may be configured with the transmission cable  160  disposed in a droop-loop fashion within the housing  110 . One or more pulleys are powered to extend the pair of transmission cables from the housing and one or more masses or resilient elements are used to retract a previously extended transmission cable.  FIG. 5A  illustrates an exemplary embodiment of the invention  500  where the transmission cable  160  is looped within a housing  510  between a converter connector  551  and an exit port  514  at a proximal portion of the conduit segment  122  and by one or more powered wheels, pulleys, or rollers, operating as one or more drive wheels. In this example, in order to extend the transmission cable  160 , at least a unidirectional rotational drive is applied to at least one of: (a) one or both of the minor guiding pulleys  571 ,  572 ; and (b) one or more major looping pulleys  521 - 523 . One or more pulleys  531 - 533  may be deployed gravitationally below the one or more powered pulleys, e.g., one or more major looping pulleys  521 - 523 , and aid in the retraction of the transmission cable  160 . These one or more lower pulleys  531 - 533  may have mass augmentation  541 - 543 , e.g., attached pendulous weights, and these one or more lower pulleys  531 - 533  may be disposed within guide channels  561 - 563 . In some embodiments, at least a bidirectional rotational drive is applied to at least one of: (a) one or both of the minor guiding pulleys  571 ,  572 ; and (b) one or more major looping pulleys  521 - 523 .  FIG. 5B  illustrates the exemplary embodiment of  FIG. 5A  in a state of transmission cable extension. The optional mass augmentation elements  541 - 543 , e.g., pendulous weights, may be further augmented or replaced by resilient elements such as springs that under tension pull downward on the lower pulleys  531 - 533 . Weights and or springs may be sized to overcome the sliding friction of the looping pulley system. Upon cessation of cable  160  extending mode, the rotation position of one or more powered pulleys, e.g., one or more major looping pulleys  521 - 523  and/or minor guiding pulleys  571 ,  572 , may be held by one or more actuated latches, such as a solenoid-actuated clamp, that, when a charging cycle is complete or if the device losses power, the one or more solenoids retract and allow the pulleys to turn freely and thereby allow the cable to retract into the looping pulley assembly due to gravity and/or spring tension. In another example,  FIG. 5C  illustrates an exemplary drive mechanism comprising the minor guiding pulleys  571 ,  572 , one of which is at least a unidirectional drive wheel, where one of the minor guiding pulleys  571 ,  572 , in this example the lower drive pulley  572 , is positioned proximate the transmission cable  160 , and attached to a mounting member  591  engaging a solenoid element  592 . Accordingly, the transmission cable  160  may be able to translate into the looped pulled assembly ( FIG. 5B ).  FIG. 5D  shows the lower pulley  572  engaging the transmission cable  160  due to the solenoid element  592  extending the mounting member  591 . Whether an active or passive retraction mechanism is embodied, the absence of the transmission cable in the conduit segment when not in use for charging a target battery protects the transmission cable from damage and/or theft. 
         [0021]      FIG. 6  shows an exploded, end-on view of another transmission cable embodiment of the invention where the pilot wire  621  and/or the ground wire  622  and/or the communication cable (not shown) are within a first conduit  630  and the pair of conductive cables  331 ,  332  are within a second conduit  640 . The minor channels shown and/or additional minor channels may be used as conduits for tow cable embodiments of a transmission cable drive mechanism. The lower minor wheel, pulley  671 , or roller and/or the upper minor wheel, pulley  672 , or roller may be used to guide and/or drive the first conduit along with the second conduit into the conduit segment  122  ( FIG. 1 ). Accordingly, additional padding material  681 ,  682  exhibiting a high sliding friction coefficient may be disposed, e.g., as a layer or a wrap, between the first conduit  630  and second conduit  640  proximate to the regions of the first conduit housing the pilot wire  621 , and/or a ground wire  622 , and/or a communication cable (not shown). The outer wall  641  of the second conduit  640  may not fully contact the inner wall  631  of the first conduit  630 , thereby allowing an air volume to be disposed between a portion of the first conduit inner wall  631  and a portion of the second conduit outer wall  641 . A blower (not shown) may be disposed within the housing  110  and may be oriented to move the volume of air from the proximal portion of the conduit segment  121  toward the distal portion of the conduit segment  123  ( FIG. 1 ). In some embodiments, the conduit assembly  120  ( FIG. 1 ) may comprise a portion of the first conduit  630  and the conduit segment  122  ( FIG. 1 ) may comprise the first conduit  630 . 
         [0022]    Additional channels may be present for embodiments with additional conductive cables such examples are shown in  FIG. 7 .  FIG. 7  shows an exploded, end-on view of another transmission cable embodiment of the invention supportive of three-phase charging where a pilot wire  721 , and/or a ground wire  722 , are within a first conduit  730  and three or four conductive cables  741 - 744 , and an optional communication cable ( 723 ), are within a second conduit  740 . The minor channels shown and/or additional minor channels may be used as conduits for tow cable embodiments of a transmission cable drive mechanism. The lower minor wheel, pulley  771 , or roller and/or the upper minor wheel, pulley  772 , or roller may be used to guide and/or drive the first conduit along with the second conduit into the conduit segment  122  ( FIG. 1 ). Material exhibiting a high sliding friction coefficient may be disposed e.g., as a layer or a wrap, between the first conduit  730  and second conduit  740  The outer wall  745  of the second conduit  740  may not fully contact the inner wall  731  of the first conduit  730 , thereby allowing an air volume to be disposed between a portion of the first conduit inner wall  731  and a portion of the second conduit outer wall  745 . A blower (not shown) may be disposed within the housing  110  and may be oriented to move the volume of air from the proximal portion of the conduit segment  121  toward the distal portion of the conduit segment  123  ( FIG. 1 ). In some embodiments, the conduit assembly  120  ( FIG. 1 ) may comprise a portion of the first conduit  730  and the conduit segment  122  ( FIG. 1 ) may comprise the first conduit  730 . 
         [0023]    Referring again to  FIG. 1 , an exemplary method of use, for example, as an EV charging station, has a user handling the conduit segment  122  via the handle-connector assembly  124  where the transmission cable  160  has not yet been extended into the conduit segment  122 . The charging conduit assembly  120  does not have the mass of the transmission cable  160  in this state. Accordingly, the user may be handling a charging conduit assembly that may be manufactured to be of a similar size, weight, and maneuverability to a conventional gasoline station fuel hose or, in some embodiments at least an assembly that is of less mass and greater maneuverability than that of a transmission cable, or cables, included therein. 
         [0024]    To initiate the extension of the transmission cables, the user may input a signal via a user interface  112 , such as a button, at the handle-connector assembly  124 , that may be communicated to a processor via a communication cable, and/or the user may input a signal via a user interface  112  at the housing  110 . Responsive to the user input, the transmission cables are extended from the housing  110  and within the conduit segment  122  until connected with the handle-connector assembly  124 . Once a safe connection has been verified, e.g., via an electrical controller unit within the handle, flow of current via the transmission cables may begin. 
         [0025]    Referring again to  FIGS. 1 ,  4 , and  5 A- 5 B, the retraction of the transmission cable  160  may be automated in that once a full charge level and/or time of charging is achieved, a signal may be sent to the converter unit that signals the stoppage of the current flow, and that signal, or a signal based one or more similar parameters, may initiate the detachment of the transmission cable  160 , i.e., the conducting core, e.g., conductive cable  331 ,  332 , from the connector. The transmission cable may then be retracted through the conduit segment and into the housing. Once the transmission cable  160  is retracted fully, or at least retracted sufficiently to a point of protecting the ends of the conductive core, e.g., the distal ends of the conductive cables  331 ,  331 , the user may be signaled, e.g., by lights, a user interface panel, and/or an audible bell and/or an automated voice, e.g., “return the handle to its cradle,” to return the conduit assembly, to its resting position at or about the housing of the charging device. In some embodiments, the handle  424  may be attached or affixed to the vehicle in such a fashion that the handle  424  cannot be removed by the user until a disengaging signal is sent to the handle indicating that the transmission cable  160  has retracted sufficiently from the conduit segment  122 . 
         [0026]    The invention in its several embodiments may not be limited to a transmission cable for EV charging stations, and may include other embodiments and applications where reduction of transmission cable weight is desirable for its handling and the absence of the transmission cables in a conduit prior to charging may be preferred on a basis of improved human safety. Embodiments of the present invention may be enhanced with the inclusion of one or more safety switches and electrical control circuitry that may be included so the user is assured of these measures. 
         [0027]    Embodiments may be configured with various cable drive mechanisms and other ways of extending and retracting the transmission cable. For example, in addition to a pair of opposed dual wheels, pulleys, or rollers,  271 ,  272 ,  571 ,  572  ( FIGS. 1 and 5A ) that may have troughs for a snug cable fitting, the transmission cables may be pulled through the conduit segment  122  by a small diameter, nonconductive, tow cable where the tow cable may be driven by one or more powered wheels, pulleys, or rollers. A cable collar, preferably nonconductive, may be connected to either a reciprocating tow cable, i.e., configured in tandem with the extending tow cable, or a second tow cable, independent of the extending tow cable, may be used to retract the transmission cable. For some smaller diameter transmission cable  160 , the transmission cable  160  may be drawn into a partial vacuum, or otherwise respond to a pressure differential created on the handle-connector portion  124  of the conduit  120  by a vacuum device that may be located within the housing  110  and a vacuum tube (not shown) integral to the conduit segment  122  and/or via a blower (not shown) located within the housing  110  impinging on an air-blocking collar disposed about a distal portion of the transmission cable  160 . 
         [0028]    The core of the transmission cable may be made of copper wire strands braided and/or twisted together. The conduit and the transmission cable covering may be made of weather resistant synthetic rubbers, such as neoprene. Plastics, including thermosetting plastics, may be used in insulative conduit connections. Polytetrafluoroethenes, such as TELFON™ by DuPont De Nemours and Company Corporation, may be used for surfaces having low sliding friction coefficients. 
         [0029]    It is contemplated that various combinations and/or subcombinations of the specific features and aspects of the above embodiments may be made and still fall within the scope of the invention. Accordingly, it should be understood that various features and aspects of the disclosed embodiments may be combined with or substituted for one another in order to form varying modes of the disclosed invention. Further it is intended that the scope of the present invention herein disclosed by way of examples should not be limited by the particular disclosed embodiments described above.