Abstract:
A vehicle charging arrangement includes a first vehicle charging connector and a second vehicle charging connector, one of the first and second vehicle charging connectors being mountable to a vehicle and the other of the first and second vehicle charging connectors being mountable to a charging gantry, the first vehicle charging connector comprising a first elongate conductor and a second elongate conductor, each of the first and second elongate conductors having a contact area with a proximal end close to the other conductor and a distal end further from the other conductor, the first and second elongate conductors being disposed parallel to each other and spaced from each other in a direction parallel with longitudinal axes of the conductors.

Description:
[0001]    The present invention relates to vehicle charging connectors. 
       BACKGROUND TO THE INVENTION 
       [0002]    Electric vehicles, and in particular electric buses, are known. Electric buses offer the potential of urban public transport which is quieter and less polluting than buses powered by diesel engines, improving the air quality and level of noise in city centres. However, various practical problems have prevented widespread adoption of electric vehicle technology. 
         [0003]    Some electric vehicles, such as trams, receive power directly from an electrical grid, for example by overhead lines. However, installing tram systems requires a great deal of initial investment, and once installed the route of a tram cannot easily be altered. 
         [0004]    Electric buses avoid these problems by storing power in batteries carried on the bus. These batteries must be regularly charged. 
         [0005]    One method of charging batteries in an electric bus involves the use of an overhead charging gantry, having conductors which deliver power through receiving conductors mounted to the roof of the bus. One such arrangement is disclosed in GB2475703. In this arrangement, two movable pantographs are provided on the roof of the bus, one behind the other. The pantographs can be moved upwards from the bus to meet charging conductors on a charging gantry, to charge the batteries of the bus. 
         [0006]    When charging a vehicle, it is known to provide a “pilot” connection for allowing communication between the charger and the vehicle being charged. The pilot connection is used to test, among other things, continuity of the charging conductors before charging begins. 
         [0007]    Although the above-described charging arrangement is designed to allow for a certain amount of tolerance in the position of the vehicle, it is possible for the vehicle to be parked at the very edge of its tolerance. In this state, the charging conductors on the charger would be electrically connected to the receiving conductors on the vehicle, but the connection may not be sound enough to effect safe charging at high current. There may be only a small area of contact between a charging conductor and its respective charge receiving member. However, this will not be apparent when performing a low-current test using a pilot connector. If charging begins when the connection is poor, there is a risk of overheating, damage to equipment, and possibly fire. 
         [0008]    A further problem with the charging arrangement of GB2475703 is that it relies on moving parts to engage and disengage the vehicle from the charging station. If the pantographs on the roof of the bus cannot be moved for some reason, for example, due to failure of a power supply, motor, or control electronics, then the bus cannot be moved out of the charging station without causing damage to components. 
         [0009]    It is an object of the invention to reduce or substantially obviate the above-mentioned problems. 
       STATEMENT OF INVENTION 
       [0010]    A vehicle charging arrangement comprising first and second connectors, one connector being mountable to a vehicle and the other connector being mountable to a charging gantry,
       the first connector comprising first and second elongate conductors, each of the first and second elongate conductors having a contact with a proximal end close to the other conductor and a distal end further from the other conductor, the first and second elongate conductors being longitudinally spaced and disposed parallel or in-line with each other,   the contact of the second elongate conductor having a longitudinal extent which is shorter than a longitudinal extent of the contact of the first elongate conductor, and   the second connector comprising third and fourth elongate conductors, the third and fourth elongate conductors having longitudinal axes running parallel with each other, and the third and fourth elongate conductors being spaced from each other in a direction perpendicular to their longitudinal axes,   the spacing between the third and fourth elongate conductors being greater than the distance between the distal end of the contact of the second elongate conductor and the proximal end of the contact of the first elongate conductor, and being shorter than the distance between the proximal end of the contact of the second elongate conductor and the distal end of the contact of the first elongate conductor.       
 
         [0015]    The spacing between the third and fourth elongate conductors may be greater than the distance between the distal end of the contact of the second conductor and the proximal end of the contact of the first conductor by a margin of at least 2.5 cm, preferably at least  5 cm. Likewise, the spacing between the third and fourth elongate conductors may be shorter than the distance between the proximal end of the contact of the second elongate conductor and the distal end of the contact of the first elongate conductor by a margin of at least 2.5 cm, preferably 5 cm. 
         [0016]    In use, the first elongate conductor of the first connector may contact the third elongate conductor of the second connector, and the second elongate conductor of the first connector may contact the fourth elongate conductor of the second connector. 
         [0017]    The position and shorter extent of the second elongate conductor ensures that a connection will only be made by the second elongate conductor when a strong and stable connection is made by the first elongate conductor. If the first elongate conductor is positioned such that it is only in contact with the third elongate conductor at its very edge, then the second elongate conductor will not contact the fourth elongate conductor at all. An electrical connection can only be made between the second and fourth elongate conductors when the first vehicle charging connector is positioned with respect to the second vehicle charging connector such that the first elongate conductor is in contact with the third elongate conductor at a point inward of either end of the first elongate conductor. In this position, a maximum contact area will be realised, ensuring maximum conductivity. This position, inward of the ends, also ensures a degree of tolerance to any movement of the connector during the charging process. 
         [0018]    The first elongate conductor may be adapted to provide a high power connection with the third elongate conductor, and the second elongate conductor may be adapted to provide a low power connection with the fourth elongate conductor. For example, the first and third elongate conductors may provide a connection for power transfer to charge batteries, whilst the second and fourth elongate conductors may provide an earth or pilot connection. 
         [0019]    The first connector may be mountable to a vehicle and the second connector may be mountable to a charging gantry. Alternatively the first connector may be mountable to a charging gantry and the second connector may be mountable to a vehicle. Either way, the elongate conductors of the first connector are preferably substantially perpendicular to a longitudinal axis of the vehicle, and the conductors of the second connector are preferably substantially parallel to the longitudinal axis of the vehicle, when the charging arrangement is in use and the vehicle is receiving a charge. 
         [0020]    In this way, the charging arrangement provides a reasonable degree of forward-backward and sideways tolerance, so that a driver can park a vehicle under a charging gantry and initiate charging quickly. When the second and fourth elongate conductors (possibly a pilot connection) are connected, the first elongate conductor is guaranteed to be mated with the third elongate conductor inward of its edge, so that a good stable connection is formed. 
         [0021]    The charging gantry may be an overhead charging gantry and one of the connectors may be mounted to a vehicle roof. 
         [0022]    Most preferably the first connector is mounted to a vehicle roof and the second connector is mounted to a charging gantry. This arrangement is preferable, since the first connector can be readily embodied in a lightweight form, to increase the operating efficiency of the vehicle. 
         [0023]    The first vehicle connector may further comprise fifth and sixth elongate conductors,
       each of the fifth and sixth elongate conductors having a contact with a proximal end close to the other of the fifth and sixth conductors and a distal end further from the other of the fifth and sixth conductors,   the contact of the sixth elongate conductor having a longitudinal extent which is shorter than a longitudinal extent of the contact area of the fifth elongate conductor,   the fifth and sixth elongate conductors running parallel with the first and second elongate conductors, and   the second connector further comprising seventh and eighth elongate conductors, the seventh and eighth elongate conductors having longitudinal axes running parallel with each other,   the seventh and eighth elongate conductors being spaced from each other in a direction perpendicular to the longitudinal axes of the seventh and eighth elongate conductors,   the spacing between the seventh and eighth elongate conductors being greater than the distance between the distal end of the contact of the sixth conductor and the proximal end of the contact of the fifth conductor, and being shorter than the distance between the proximal end of the contact of the sixth elongate conductor and the distal end of the contact of the fifth elongate conductor.       
 
         [0030]    In other words, the arrangement of first, second, third and fourth elongate conductors may be repeated to make a total of four elongate conductors on each of two connectors. The arrangement may be repeated with the duplicate arrangements one behind the other. The appropriate arrangement in a given scenario will depend on the dimensions of the vehicle and space available on the roof, any restrictions on the charging gantry in terms of height and size, and so on. 
         [0031]    The first and third elongate conductors may be used to provide a positive charging connection; the second and fourth elongate conductors may be used to provide a pilot connection; the fifth and seventh elongate conductors may be used to provide a negative charging connection; and the sixth and eighth elongate conductors may be used to provide a ground connection. 
         [0032]    When continuity is successfully detected between the pilot and ground connections, good positive and negative charging connections can be guaranteed. 
         [0033]    The first and second elongate conductors may be disposed along the same line as each other. Where provided, the fifth and sixth elongate conductors may also be disposed along the same line as each other. An insulator may be provided between the first and second elongate conductors, and an insulator may be provided between the fifth and sixth elongate conductors. In this way, the first and second elongate conductors with an insulator may form a continuous bar, and the fifth and sixth conductors with an insulator may for another continuous bar. However, it is also envisaged that, as an alternative, an air gap may be provided between the first and second conductors, and/or between the fifth and sixth conductors. 
         [0034]    Either the vehicle-mounted connector or the gantry-mounted connector may be movable, whichever of the first and second connectors is the vehicle-mounted connector. The other connector may be mounted to the vehicle or charging gantry in a fixed position. In use, whichever connector is movable may be moved to meet the connector which is fixed. 
         [0035]    Most preferably, both of the first and second connectors are movable and, in use, move towards each other to meet each other. This has the advantage that, if either of the two moving mechanisms should fail for any reason, then the vehicle will not be trapped in the charging gantry, since it can come free by moving whichever moving mechanism is not broken or faulty. 
         [0036]    At least one movably mountable connector may be movable substantially in an arc, on a pivoting arm, between a retracted position and an extended position. 
         [0037]    The pivoting connector in the extended position may be biased towards the extended position, but pivotable towards the retracted position on application of a force to the connector. In this way, a vehicle can escape from a charging gantry even when the moving mechanism of the movable connector has failed, and the other connector is mounted in a fixed position or has also failed. In this situation, where the pivoting connector is fitted to the vehicle, the vehicle may be driven in a direction with the point where the pivoting arm is mounted to the vehicle being forward-most, and with the elongate conductors trailing behind. If the pivoting connector is part of the charging gantry, then the vehicle may be driven out of the gantry in a direction with the elongate conductors forward-most, and with the pivoting arm trailing behind. 
         [0038]    The contact of the second elongate conductor and, where provided, the sixth elongate conductor, may be vertically offset from the contact of the first and fifth elongate conductors respectively. 
         [0039]    The fourth and, where provided, the eighth elongate conductor may be biased towards a rest position, and may be movable out of the rest position in a direction perpendicular to the longitudinal axis of the fourth elongate conductor and also perpendicular to the spacing between the third and fourth elongate conductors. 
         [0040]    A biased and movable fourth (and/or eighth) conductor ensures that the pilot and ground connections are made first, before the high power charging connections. This feature also ensures that a good connection can be made where the first and second conductors do not form a completely straight line, and/or when the fifth and sixth conductors do not form a completely straight line, possibly because some of the conductors have become damaged. Furthermore, the biased and movable conductor provides for a good connection with the charging gantry when the vehicle is parked on a sideways slope. 
         [0041]    A contact of the fourth elongate conductor may be shorter than a contact of the third elongate conductor, and the contacts of the third and fourth elongate conductors may be disposed side-by-side, both ends of the contact of the fourth elongate conductor being located inwardly of the ends of the contact of the third elongate conductor. 
         [0042]    The contacts of the third and fourth elongate conductors may have elongate extents substantially parallel with the third and fourth conductors themselves. 
         [0043]    In the same way that the shorter contact of the second conductor ensures a good connection of the first and third conductors at the sideways extreme of the parking tolerance of the charging arrangement, a shorter contact of the fourth conductor ensures a good connection of the first and third conductors at the lengthways extreme of the parking tolerance of the charging arrangement. 
         [0044]    Where an eighth elongate conductor is provided, a contact of the eighth elongate conductor may likewise be shorter than a contact of the seventh elongate conductor. 
         [0045]    The fourth and, where provided, eighth elongate conductor may have a width perpendicular to its longitudinal axis and parallel with the spacing between the third and fourth elongate conductors which is smaller than a corresponding width of the third and, where provided, seventh elongate conductor. 
         [0046]    The third elongate conductor may be separated from the seventh elongate conductor by a first insulator, and the fourth elongate conductor may be separated from the eighth elongate conductor by a second insulator. In this way, the second connector may comprise of a pair of parallel bars, one bar including the third elongate conductor, the first insulator and the seventh elongate conductor, and the other bar including the fourth elongate conductor, the second insulator and the eighth elongate conductor. 
         [0047]    The second insulator may have a length parallel with the third, fourth, seventh and eighth elongate conductors which is longer than a corresponding length of the first insulator, thus providing for shorter fourth and eighth conductors with their ends inward of the third and seventh conductors as described above. 
         [0048]    An outer surface of at least one of the first and second insulators may be set inwardly of outer surfaces of the third, fourth, seventh and eighth elongate conductors which mount the contacts of the respective conductors. In this way, a contact surface of the second vehicle charging connector may have an inset insulating portion. 
         [0049]    According to a second aspect of the present invention, there is provided a vehicle charging connector comprising a first elongate conductor and a second elongate conductor, each of the first and second elongate conductors having a contact with a proximal end close to the other conductor and a distal end further from the other conductor, the first and second elongate conductors being longitudinally spaced and disposed parallel or in-line with each other, the contact of the second elongate conductor having a longitudinal extent which is shorter than a longitudinal extent of the contact of the first elongate conductor. 
         [0050]    Preferable and/or optional features of the second aspect of the invention are set out in appended claims  30  to  47 . 
         [0051]    According to a third aspect of the invention, there is provided a vehicle charging connector comprising first and second elongate conductors, the first and second elongate conductors having longitudinal axes running parallel with each other, and the first and second elongate conductors being spaced from each other in a direction perpendicular to the longitudinal axes of the first and second elongate conductors, a contact of the second elongate conductor being shorter than a contact of the first elongate conductor, and the first and second elongate conductors being disposed side-by-side, with both ends of the contact of the second elongate conductor located inwardly of the ends of the contact of the first elongate conductor. 
         [0052]    Preferable and/or optional features of the third aspect of the invention are set out in appended claims  49  to  64 . 
         [0053]    According to a fourth aspect of the invention, there is provided a vehicle charging connector comprising first and second elongate conductors, the first and second elongate conductors having longitudinal axes running parallel with each other, and the first and second elongate conductors being spaced from each other in a direction perpendicular to their longitudinal axes, the second elongate conductor being biased into a rest position and being movable out of the rest position in a direction perpendicular to the longitudinal axis of the second elongate conductor and also perpendicular to the spacing between the first and second elongate conductors. 
         [0054]    Preferable and/or optional features of the fourth aspect of the invention are set out in appended claims  66  to  80 . 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0055]    For a better understanding of the present invention, and to show more clearly how it may be carried into effect, reference will now be made, by way of example, to the accompanying drawings. in which: 
           [0056]      FIG. 1  shows a perspective view of a vehicle charging arrangement in use, charging a bus; 
           [0057]      FIG. 2  shows a plan view from above of the vehicle charging arrangement of  FIG. 1 ; 
           [0058]      FIG. 3  shows a perspective view from in front of the vehicle charging arrangement of  FIG. 1 , with the vehicle disengaged from the charging gantry; and 
           [0059]      FIG. 4  shows a schematic plan view from above of charging conductors, forming part of the charging arrangement of  FIG. 1 . 
       
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0060]    Referring firstly to  FIG. 1 , a vehicle charging arrangement is generally indicated at  10 . The vehicle charging arrangement includes a first connector  12 , and a second connector  13 . The first and second connectors  12 ,  13  include four elongate conductors each, that is, eight conductors in all. In this embodiment, the first connector  12  is mounted to the roof of a bus  200 , and the second connector  13  is provided on an overhead charging gantry  210 . 
         [0061]    The first connector  12  includes first, second, fifth and sixth elongate conductors  16 ,  18 ,  20 ,  22 . The first and second elongate conductors are disposed in the same line as each other. each extending from opposite sides of a insulated mount  24 . Likewise, the fifth and sixth elongate conductors  20 ,  22  are disposed in the same line as each other, extending from opposite sides of another insulated mount  26 . 
         [0062]    The first and second elongate conductors  16 ,  18 , together with their corresponding mount  24 , form a substantially horizontal bar above the roof of the bus, and are pivotally mounted to the roof of the bus via a movable arm  28 . The fifth and sixth elongate conductors  20 ,  22  and mount  26  are likewise mounted to the bus on movable arm  30 . 
         [0063]    Movable arms  28  and  30  can be operated to move first, second, fifth and sixth elongate conductors  16 ,  18 ,  20 ,  22  between an extended position, as shown in  FIG. 1 , and a retracted position in which the pivotal arms  28 ,  30  and the elongate conductors  16 ,  18 ,  20 ,  22  are all disposed in a substantially horizontal plane just above the roof of the bus  200 . The arms  28 ,  30 , may be moved for example by electric motors. However, when the arms  28 ,  30  are in the extended position, they can be pressed downwardly towards the retracted position on application of a force to the elongate conductors  16 ,  18 ,  20 ,  22  from above. The arms  28 ,  30  are biased into the extended position and will therefore spring back to the extended position when any force is removed. 
         [0064]    When the arms  28 ,  30  are in the retracted position, they may be locked against the roof of the bus  200 , preventing any movement by applying force directly to the conductors  16 ,  18 ,  20 ,  22 . The arms  28 ,  30  can only be moved from the retracted position to the extended position, and can only be locked into the retracted position, by operating the electric motors or other movement means. 
         [0065]    The second connector  13  comprises third, fourth, seventh and eighth elongate conductors  32 ,  34 ,  36 ,  38 . As shown in the Figure, the first elongate conductor  16  connects with the third elongate conductor  32 , the second elongate conductor  18  connects with the fourth elongate conductor  34 , the fifth elongate conductor  20  connects with the seventh elongate conductor  35 , and the sixth elongate conductor  22  connects with the eighth elongate conductor  38 . 
         [0066]    The first and third  16 ,  32  and the fifth and seventh  20 ,  26  elongate conductors provide high-power charging connections. The second and fourth  18 ,  34  and sixth and eighth  22 ,  38  elongate conductors provide low-power pilot and earth connections. As is clear from the Figure, the fourth and eighth elongate conductors  34 ,  38  are substantially thinner than the third and seventh elongate conductors  32 ,  36 . 
         [0067]    A first insulator  40  is provided between the third and seventh elongate conductors  32 ,  36 , and a second insulator  42  is provided between the fourth and eighth elongate conductors  34 ,  38 . The third elongate conductor  32 , the first insulator  40  and the seventh elongate conductor  36  form a bar and the fourth elongate conductor  34 , the second insulator  42  and the eighth elongate conductor  38  form another bar, the two bars running parallel to each other, and spaced by around  50 cm from each other. 
         [0068]    The first and second insulators  40 ,  42  are thinner than the conductors  32 ,  36 ,  34 ,  38  to which they are respectively connected. In this way. the insulators form waisted sections of the bars. In particular, a contact surface of the second vehicle connector  12  has inset insulating sections between the conducting parts. The contact surface faces the bus  200  in the Figure. 
         [0069]    Referring now to  FIG. 2 , the first connector  12  and second connector  13  are shown from above. In this Figure, the relative lengths and widths of the third, fourth, seventh and eighth elongate conductors  32 ,  34 .  36 ,  38 , and the first and second insulators  40 ,  42 , are clearly visible. In particular, the eighth elongate conductor  38  has both ends inward of the ends of the seventh elongate conductor  36 , as shown by lines AA and BB. The second insulator  42  is longer than the first insulator  40 . 
         [0070]    Referring now to  FIG. 3 , the pivoting arms  28 ,  30  of the first connector  12  are shown in a partially extended position. The biasing arrangement of the second charging conductor  13  is also illustrated in this Figure. The fourth and eighth elongate conductors  34 ,  38  are mounted to the charging gantry  210  via springs, and are suspended on the springs a few centimetres below the level of the third and seventh elongate conductors  32 ,  36 . When the first connector  12  is extended to meet the second connector  13 , the second and sixth elongate conductors  18 ,  22  will push upwardly on the fourth and eighth elongate conductors  34 ,  38 . As a result, the fourth and eighth elongate conductors  34 ,  38  will move against the springs  44 . In this way, the vertical offset between the third and seventh elongate conductors  32 ,  36  and the fourth and eighth elongate conductors  34 ,  38  is automatically adjusted when the vehicle is engaged in the charging station. If the vehicle is parked on a flat surface and the conductors are undamaged then the fourth and eighth elongate conductors  34 ,  38  will be lifted to the same height as the third and seventh elongate conductors  32 ,  36  when charging is in progress. 
         [0071]    The force required to move the fourth and eighth elongate conductors  34 ,  38  against the springs  44  is around  10  to  15  Newtons. The pivoting arms  28 ,  30  may push the second and sixth elongate conductors  18 , ( 22 ) with a force of around  80  Newtons. Therefore, when charging, the first and second connectors  12 ,  13  will push against each other with a force of around  65  Newtons, which is sufficient to provide a good electrical contact. 
         [0072]    The arrangement of the first and second elongate conductors  16 ,  18  is best seen in  FIG. 4 . The first and second elongate conductors  16 ,  18  extend from either side of a central insulating mount  24 . The overall extent of the first and second conductors  16 ,  18  from the mount  24  is similar. However, the actual contact area  46  which can form an electrical connection with the second charging connector  13  is substantially reduced on the second elongate conductor  18  relative to the first elongate conductor  16 . The contact area of the first elongate conductor extends across substantially the entire length of the conductor  16 . The contact area  46  of the second elongate conductor  18  has an overall shorter length than the contact area of the first elongate conductor  16 . 
         [0073]    The contact area  46  of the second elongate conductor  18 , together with the spacing between the third and fourth conductors ( 32 ,  34 ) defines a working area  48  on the first elongate conductor  16 . The working area  48  is inward of the ends of the first elongate conductor  16 , ensuring a good stable connection to the first elongate conductor  16 . 
         [0074]    It will be appreciated that the arrangement of contact areas can be embodied in a number of different ways. For example, the contact area  46  of the second elongate conductor  18  may be formed as a raised area on a surface of the conductor, or as a conducting section surrounded by insulating material. Alternatively, the central mount  24  may be extended and the second elongate conductor  18  shortened, with the contact area  46  extending along the entire length of the second elongate conductor  18 . 
         [0075]    The embodiments described above are provided by way of example only, and various changes and modifications will be apparent to persons skilled in the art without departing from the scope of the present invention as defined by the appended claims.