Abstract:
A railway truck is provided comprising first and second wheelsets, each wheelset comprising at least a left and a right wheel adjacent opposite ends of an axle. Each axle is supported for rotation about an axle axis by a respective bearing adjacent the left and right wheels. A first frame member extends between a bearing support adjacent the left wheel of the first wheelset and a bearing support adjacent the right wheel of the second wheelset. A second frame member extends between a bearing support adjacent the left wheel of the second wheelset and a bearing support adjacent the right wheel of the first wheelset. The first and second frame members are free to move without interference from each other to cause the truck to steer in response to a change in a rolling direction of either of the first and second wheelsets.

Description:
FIELD OF INVENTION 
       [0001]    The present invention relates generally to rail transport. More specifically the present invention relates to railway trucks (“bogies”) for supporting railcars. 
       BACKGROUND OF INVENTION 
       [0002]    Railway cars, including streetcars and subway cars traditionally ride on a pair of parallel rails. The rails are engaged by respective wheels of a railway truck. 
         [0003]    Traditional railway trucks include a pair of generally parallel sideframes connected by a transversely extending bolster. The bolster supports an overlying railway car. 
         [0004]    In a traditional railcar the wheels are rigidly secured to opposite ends of an axle in an assembly referred to as a “wheelset”. The railway truck typically has a pair of generally parallel wheelsets and the railway truck maintains the wheelsets in the generally parallel configuration. 
         [0005]    A first disadvantage of traditional railcars is the requirement of having a pair of rails which much be maintained in a generally parallel spaced apart relationship. This arrangement is capital and labour intensive. 
         [0006]    A further disadvantage of traditional railcars is their inability to steer given that the wheelsets are supported with their respective axles generally parallel. Although the railway truck may swivel relative to an overlying railcar, the wheelsets remain in a fixed alignment. Accordingly the wheels generally align poorly with railway tracks in corners causing slippage between the wheels and the tracks which causes the characteristic squeal of subway cars and streetcars in negotiating corners and as well damage to the tracks arising from the slippage. 
         [0007]    It is an object of the present invention to provide a railway truck and a rail system which overcomes at least some of the problems set out above with traditional railcar and railway systems. 
       SUMMARY OF THE INVENTION 
       [0008]    According to one aspect of the present invention, a railway truck is provided comprising first and second wheelsets, each wheelset comprising at least a left and a right wheel adjacent opposite ends of an axle, the left and rights wheels of the first and second wheelsets respectively are alignable to follow a common path. Each axle is supported for rotation about an axle axis by a respective bearing adjacent the left and right wheels. Each bearing is supported in a respective bearing support. A first frame member extends between the bearing support adjacent the left wheel of the first wheelset and the bearing support adjacent right wheel of the second wheelset. The first frame member is swivelably coupled to the bearing support for rotation about an axis orthogonal to the axle axis. A second frame member extends between the bearing support adjacent the left wheel of the second wheelset and the bearing support adjacent the right wheel of the first wheelset. The second frame member is swivelably coupled to the bearing supports for rotation about an axis orthogonal to the axle axis. The first and second frame members are free to move without interference from each other to cause the left and right wheels respectively to move toward or away from each other in response to movement in the opposite direction by the other of the left and right wheels to cause the truck to steer in response to a change in a rolling direction of either of the first and second wheelsets. 
         [0009]    According to another aspect of the present invention, a streetcar is provided, comprising a railway truck, as defined herein, at opposite ends thereof; at least one motor coupled to at least one of the wheelsets for driving the wheelset; a motor control means for controlling the driving of the wheelset by the motor; and a power receptor mounted to the streetcar for receiving electricity from a source of electricity, the power receptor being electrically coupled to the at least one motor through the motor control means. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0010]    A detailed description of the invention is set out below with reference to the accompanying illustrations in which: 
           [0011]      FIG. 1  is a plan view of a railway truck according to the present invention; 
           [0012]      FIG. 2  is a side elevation corresponding to  FIG. 1 ; 
           [0013]      FIG. 3  is an end view corresponding to  FIG. 1 ; 
           [0014]      FIG. 4  is a plan view of an exemplary embodiment of a railway truck according to the present invention; 
           [0015]      FIG. 5  is a plan view of an exemplary embodiment of a railway truck according to the present invention; 
           [0016]      FIG. 6  is a perspective view of two housings according to the present invention; 
           [0017]      FIG. 7  is an end view of a railway truck according to the present invention; 
           [0018]      FIG. 8  is an end view of a streetcar mounted on a railway truck according to the present invention; 
           [0019]      FIG. 9  is an end view of a streetcar mounted on an alternate embodiment of a railway truck according to the present invention; 
           [0020]      FIG. 10  is an end view of a streetcar mounted on another alternate embodiment of a railway truck according to the present invention; 
           [0021]      FIG. 11  is a plan view of the outline of a streetcar mounted on two railway trucks according to the present invention; 
           [0022]      FIG. 12  is an exploded view of a guiding wheel in the present invention; and, 
           [0023]      FIG. 13  is an end view of an assembled guiding wheel. 
       
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0024]    A railway truck according to the present invention is generally indicated by reference numeral  20  in the accompanying illustrations. The railway truck  20  has a first wheelset  30  and a second wheelset  50 . As the first and second wheelsets  30  and  50  are virtually identical, common reference numerals are used herein for their component parts. Each of the first and second wheelsets  30  and  50  respectively has a respective left wheel  70  and right wheel  72  adjacent opposite ends of an axle  74 . The left wheel  70  and right wheel  72  are alignable, as set out in more detail below to follow a common path defined either by a spaced apart pair of conventional parallel railroad tracks (not shown) or a single monorail track  90 . 
         [0025]    Each axle  74  is supported for rotation about an axle axis  82  by a respective bearing  78  adjacent each of the left and right wheels  70  and  72  respectively. Each bearing  78  is supported in a respective bearing support  80 . 
         [0026]    A first frame member  100  extends between the bearing support  80  adjacent the left wheel  70  of the first wheelset  30  and the bearing support  80  adjacent the right wheel  72  of the second wheelset  50 . The bearing supports  80  are swivelably coupled to the first frame member  100  for rotation about an axis  102  (shown in dashed lines in  FIG. 3 ) orthogonal to the axle axis  82  about which the left wheel  70  and right wheel  72  are rotatable. The left wheel  70  and right wheel  72  may each be a rim shod with a tyre of rubber or other suitable material for engaging a road surface  94 . 
         [0027]    In like manner, a second frame member  120  extends between the bearing support  80  adjacent the left wheel  70  of the second wheelset  50  and the bearing support  80  adjacent the right wheel  72  of the first wheelset  30 . The second frame member  120  is swivelably coupled to the bearing supports  80  for rotation about an axis  102  orthogonal to the axle axis  82 . The axis  82  is shown as a dashed line in  FIG. 1 . Both of the frame members are contoured to allow a crossover of the first and second frame members without interference therebetween. 
         [0028]    Either or both of the first and second frame members  100 ,  120  may support a portion of an overlying rail car. Typically some form of bearing would be interspersed between the first and second frame members  100  and  120  respectively and the rail car to enable the railway truck  20  swivel relative to the railcar. 
         [0029]    The left wheel  70  and right wheel  72  are road engaging wheels for riding on a road surface  94 , with the guiding wheel  104  being a rail engaging wheel configured to straddle a monorail track  90  to guide the wheelsets  30 ,  50  and in turn to guide the railway truck  20 . The guiding wheels  104  ride along a monorail and the left wheel  70  and right wheel  72  provide additional support on the left and right side of the railway truck  20 . 
         [0030]    Guiding wheels  104  have a track engaging surface  108  extending circumferentially thereabout between opposing flanges  106 . The flanges  106  are spaced apart and extend radially outwardly beyond the track engaging surface  108  to define in conjunction with the track engaging surface  103  a channel for receiving the track. The channel  108  receives and rides on a monorail track  90  with the flanges  106  engaging opposite sides of the monorail track  90  to maintain the track engaging surface  108  thereon. The track engaging surface  108  is preferably a flat surface. 
         [0031]    The guiding wheel  104  may have a diameter which is as great or greater than the diameter of the left and right wheels  70 ,  72  so that the guiding wheel  104  engages the monorail track  90  when the monorail track  90  is embedded in a road surface  94 . The diameter of the guiding wheel  104  (including the flanges  108 ) in this embodiment is larger than the diameter of the left and right wheels  70 . Accordingly the guiding wheel extends below the road surface to engage the monorail  90  as shown in  FIGS. 2 and 3 . The track engaging surface  108  is sized to engage the upper surface  92  of the monorail  90  and the flanges  106  maintain the guiding wheels  104  on the monorail track  90 . 
         [0032]    Embedding the monorail track  90  into the underlying surface is a preference where the underlying surface is to be shared with other vehicles such as cars. In situations where this is not the case the monorail track  90  may be placed on the underlying surface to extend above it such as illustrated in  FIGS. 7 through 10 . 
         [0033]    In another embodiment, as shown in  FIG. 4 , a first housing  402  attaches to the first wheelset  30  along the axis between the left and right wheels  70 ,  72 . Similarly, a second housing  404  attaches to the second wheelset  50  along the axis between the left and right wheels  70 ,  72 . A substantially straight first scissor bar  406  extends from the portion of the upper surface  422  of the first housing  402  near the right wheel  72  of the first wheelset  30  to the portion of the upper surface  420  of the second housing  404  near the left wheel  70  of the second wheelset  50 . The scissor first and second bars  406  and  408  respectively are analogous to the first and second frame members  100  and  120  in the  FIGS. 1-3  embodiment. The housings  402  and  404  are analogous to the bearing supports  80  except that each housing supports two bearings and therefore acts as a pair of bearing supports. 
         [0034]    Similarly, a substantially straight second scissor bar  408  extends from the portion of the upper surface  422  of the second housing  404  near the left wheel  70  of the second wheelset  50  to the portion of the upper surface  420  of the first housing  404  near the right wheel  72  of the first wheelset  30 . 
         [0035]    The first scissor bar  406  has a first end  410  pivotally attached to the portion of the upper surface  422  of the first housing  402  near the right wheel  72  of the first wheelset  30 . The first scissor bar  406  has a second end  412  pivotally attached to the portion of the upper surface  420  of the second housing  404  near the left wheel  70  of the second wheelset  50 . 
         [0036]    Similarly, the second scissor bar  408  has a first end  414  pivotally attached to the portion of the upper surface  422  of the first housing  402  at near the left wheel  70  of the first wheelset  30 . The second scissor bar  408  also has a second end  416  pivotally attached to the portion of the upper surface  420  of the second housing  404  near the right wheel  72  of the second wheelset  50 . 
         [0037]    In an alternative embodiment, shown in  FIG. 5 , the scissor bars  408 ,  406  may be pivotally connected as in the above embodiment with the exception that they are pivotally connected to the lower surface of the first and second housing  402 ,  404 , which is opposite the upper surface  422 ,  420 . 
         [0038]    In the embodiment shown in  FIG. 5 , a left extension member  502  and a right extension member  504  project from the front edge  506  of the first housing  402 . The left extension member  502  and the right extension member  504  have an axle (not shown) projecting therebetween. A front guiding wheel  104  rotationally mounts onto the axle that projects between the left extension member  502  and the right extension member  504 . The front guiding wheel  104  is aligned with the guiding wheel  104  underneath the first housing  402  for riding on a monorail track  90 . 
         [0039]    The pivotal attachment of the first and second scissor members  406 ,  408  allows the first and second wheelsets  30 ,  50  to pivot independently relatively to each other. When the first wheelset  30  pivots with respect to the second wheelset  50  along a surface plane, for example, the scissor members  406 ,  408  pivot on the first and second housing  402 ,  404 , respectively. Thus, the first housing  402  and first wheelset  30  may pivot between a fully turned position as shown in  FIG. 5  and a straight position as shown in  FIG. 4 . 
         [0040]      FIG. 6  shows a close-up of the first and second housing  402 ,  404 . Each of the first and second housings  402 ,  404  have a main portion with a top plate  610  having an upper planar surface  420 ,  422  with side flanges  612  extending from opposing two ends of the top plate  610  in the same direction, which is perpendicular to the top plate  610 . Each of the side flanges  612  has an aperture  602  through which the axle  74  passes when connected to the left and right wheels  70 ,  72 . There is a singular aperture  604  through the planar surface of the first housing  402  for receiving an attachment mechanism from a load bearing device, such as a streetcar or truck. The planar surface of the second housing  404  has an extended aperture  606  for slidably engaging with an attachment element of the load bearing device. 
         [0041]      FIG. 7  shows the second housing  404  attached to the axle  74  of the second wheelset  50 . As shown, the scissor bars  408 ,  406  are pivotally attached by a bolt and nut to the underside of the housing  40 . 
         [0042]      FIG. 8  shows a streetcar  804  attached to the second housing  404 . An attachment element  810  extends from the bottom surface  806  of the streetcar  804  and slidably engages with the extended aperture  606 . There are two suspension coils  802  on either side of the second housing  404  abutting and engaging the bottom surface  806  of the streetcar  804 . The suspension coils  802  support the streetcar  804 . 
         [0043]    A motor (not shown) may be operatively connected to the guiding wheel  104  for driving the streetcar  804  along the monorail  90 . 
         [0044]    In a further embodiment, depicted in  FIG. 9 , the first wheelset  30  may not have an axle  74  extending from the left wheel  70  to the right wheel  72 . The left wheel  70  may be connected to a flange  612  of the housing  404  by a rotatable member  904 . Similarly the right wheel  72  may be connected to another flange  612  of the housing  404  by a rotatable member  904 . The rotatable members  904  are attached to the housing  404  and the left and right wheels  70 ,  72 , to allow the left and right wheels  70 ,  72  to rotate around their respective central axes. Similarly a motor  902  may extend from the central portion of the housing  404  and rotatably engage the guiding wheel  104  so that the guiding wheel  104  may rotate around its central axis. 
         [0045]      FIG. 10  shows a further embodiment in which the streetcar  804  is attached to the housing  404  and rests along the top surface  420  of the housing  404 . Support ledges  912  extend inwards from each of the rotatable members  904  through the flanges  612 . In this arrangement the rotatable members  904  and their accompanying flanges are vertically slidable relative to the flanges  612 . of the housing  404 . Extending downwards from the underside  806  of the streetcar  804  are two suspension blocks  910 . Coil springs  802  rest on each of the two support ledges  912  and extend upwards to engage with the suspension blocks  910 . The coil springs  802  act between the support ledges  912  and suspension blocks  910 . 
         [0046]    Although not illustrated, a streetcar or other railcar structure may be mounted to the railway truck arrangement in  FIG. 1-3  for example by mounting a bearing member midway along the first member  100  which supports the railcar structure or body and enables the railway truck  20  to swivel about an axis generally orthogonal to that of the axles  74 . 
         [0047]    As shown in  FIG. 11 , one pair of wheelsets (i.e. a first wheelset  30  and second wheelset  50  together) may be attached underneath the rear of the streetcar  804  and a second pair of wheelsets may be attached underneath the front of the streetcar  804 . The streetcar  804  in  FIG. 11  is indicated only by its outline. 
         [0048]    The extended aperture  606  allows the attachment element  810  extending from the underside  806  of the streetcar  804  to slide relative to the housing  404  (and hence the second wheelset  50 ) which allows the second wheelset  50  to pivot independently of the first wheelset  30 . The guide wheel  104  can therefore remain riding on the monorail  90  while the monorail curves (as shown at the rear in  FIG. 11 ). 
         [0049]    Referring to  FIG. 12 , the guiding wheel  104  comprises a first railway wheel  126  and a second railway wheel  128 . At least one of the railway wheels  126 ,  128  has a track engaging surface extending circumferentially thereabout between a flanged face  140  and a non-flanged face  142 . The first and second railway wheels  126 ,  128  join at their non-flanged faces  142  to define a channel for receiving and riding on a monorail track  90  with the flanges  106  engaging opposite sides of the monorail track  90  to maintain the track engaging surface on the monorail track  90 . 
         [0050]    In the embodiment shown in  FIG. 12 , the second railway wheel  128  has a circumferential flange  106  surrounding an externally threaded portion  122 . The first railway wheel  126  portion has a similar circumferential flange  106  surrounding an internally threaded portion  124 . The externally threaded portion  122  of the second railway wheel  128  is received by the internally threaded portion of the first railway wheel  126  portion to form the guiding wheel  104 . Two screws  130  and corresponding bolts  132  and washers  134  secure the second railway wheel  128  portion to the first railway wheel  126 . 
         [0051]    It will be appreciated that the above arrangement maintains the axis  82  of the wheelset generally orthogonal (at right angles when viewed from above) to the monorail track  90 . 
         [0052]    The monorail system is easy to install in situations where a smooth surface is available for the tires to ride on. In situations where railroad ties are used for track support, a suitable pad may be secured to an upper face of the ties on either side of the monorail track to provide a riding surface for the left and right wheels. 
         [0053]    Although specific embodiments of the invention have been described herein, it will be understood by those skilled in the art that variations may be made thereto without departing from the spirit of the invention or the scope of the appended claims. For example, although the presently preferred embodiment is described with respect to a monorail system, it is expected that the arrangement may be adapted to parallel rail systems by eliminating the central guidewheel and utilizing conventional railway wheels for engaging the rails.