Abstract:
An improved hi-rail wheel assembly includes a frame connected to an axle tube surrounding an axle, a pair of railway wheels mounted in spaced relation on the axle tube, a first pair of pivotal links connected between a frame and the axle, and a second pair of pivotal links connected to the frame and the axle. The hi-rail wheel assembly is attached to a conventional roadway vehicle such that the extension of said pivotal links effects a downward lowering of the axle and the railway wheels from the frame and lifts the vehicle whereby the vehicle tires engage the railroad track, and the retraction of the pivotal links effects an upward lifting of the axle and railway wheels towards the frame such that the vehicle tires engage a ground surface or roadway. Each pivotal link includes a cam aperture and a recessed cam shoulder surrounding the cam aperture to receive a cam. A cam having an eccentric aperture is used to engage the cam aperture and the recessed shoulder such that the eccentric aperture is connected to the axle. The position of the eccentric aperture with respect to the recessed cam shoulder will thereby determine the distance between the axle and the frame when the hi-rail wheel assembly is in the extended position, and consequently will affect the traction between the vehicle tires and the railroad tracks.

Description:
FIELD OF THE INVENTION 
     The present invention relates to hi-rail assemblies that allow conventional roadway vehicles to be driven on a railroad track, and, more particularly, to a hi-rail assembly having a height adjustment means and that is attachable to a conventional vehicle to allow continued traction between the vehicle tires and the rails of the railroad track after wear of the vehicle tires. 
     BACKGROUND OF THE INVENTION 
     Hi-rail capability refers to railway wheels, usually retractable, that are attached to standard roadway vehicles for the purpose of allowing the vehicles to travel on conventional railroad tracks in addition to conventional roadways. Hi-rail vehicles are commonly used as maintenance vehicles or as track inspection cars due to their mobility on both standard highways and railroad tracks. 
     A conventional hi-rail vehicle is described in U.S. Pat. No. 4,583,465 issued to Power, Sr. This design illustrates a railway wheel apparatus that allows simultaneous actuation of two cylinders to lower the railway wheel apparatus onto the railroad track. In operation, the railway wheels contact the rails and raise at least a portion of the vehicle off of the railroad track. Generally, the rear pair of vehicle wheels remain in contact with the railroad track to be able to propel the vehicle on the railroad tracks. A problem with this design is that the vehicle tires remain in constant contact with the railroad track, and subsequently will lose traction due to wear of the tire. Because the railway wheel apparatus remains at a constant position with respect to the railroad track, the wear of the vehicle tires will cause the traction between the vehicle tires and the railroad track to decrease. Consequently, in order to regain the traction lost due to wear of the vehicle tires, either the hi-rail wheel assembly must be adjusted through technical and complex mechanical adjustments of the wheels that reposition the vehicle at a lower level, which can be very complicated and require great effort, or the worn vehicle wheels will have to be replaced on the vehicle by new wheels that have not experienced the deterioration of the use, thereby discarding the worn wheels before the end of the standard life of the wheels. 
     What is needed, then, and not found in the prior art, is a hi-rail assembly that provides a means for making adjustments to reduce the distance between the hi-rail assembly and railroad tracks so that the vehicle tires will continue to make a satisfactory connection with the railroad tracks. 
     SUMMARY OF THE INVENTION 
     A further object of the present invention is to provide an improved hi-rail assembly having a height that can be altered to vary the position between the vehicle tire and the railroad track. 
     These and other objects of the invention are accomplished through the improved hi-rail assembly of the present invention. The hi-rail assembly of the present invention includes a frame that is attachable to a conventional road vehicle, an axle tube attached to the frame via a pair of is pivotal links at the two ends of the axle tube, and a pair of railway wheels attached to the ends of the axle tube that are used to engage the railroad track. The axle tube is connected to the pivotal links via a block and a block pin, such that the pivotal links will determine the distance between the frame and the axle tube when the railway wheels are in their extended position. 
     Each pivotal link of the present invention includes an upper link plate and a lower link plate. The upper link plate is pivotally connected to the lower link plate such that when pressure is applied to the pivotal link, both the lower link plate and the upper link plate will pivot, according to the direction of the pressure applied, to either an extended position to engage the railroad tracks or to a contracted position to allow the vehicle to travel on a standard roadway. The lower link plate includes a cam aperture and a recessed cam shoulder for receiving the block pin attached to the block. Furthermore, the assembly includes a locking means to secure the position of each pivotal link in either an extended or a retracted position. 
     To allow the distance between the frame and the ground surface to be adjusted to allow a worn tire to make contact with the railroad track, the lower link plate includes a recessed cam shoulder surrounding the cam aperture. The recessed cam shoulder is sized to receive a cam, and includes a number of mounting bores surrounding the outer periphery of the cam. The cam includes several attachment apertures surrounding the outer periphery of the cam, and is designed to engage the lower link plate in the space defined by the outer periphery of the bored shoulder. The cam includes an eccentric aperture located near the center of the cam aperture. The eccentric aperture will engage the block pin, and, when the cam is rotated within the lower link plate, the distance of the axle tube above the ground surface will be varied according to the placement of the eccentric aperture of the cam within the lower link plate. Thus, the distance between the frame and the axle tube will be changed, and the traction between the railroad tracks and the vehicle tires will therefore be controllable by the rotation of the cam. 
     Further aspects of the present invention will become apparent during the course of the following description and by reference to the attached drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     A hi-rail railway car assembly is depicted in the accompanying drawings which form a portion of this disclosure and wherein: 
     FIG. 1 is a side elevational view of the hi-rail wheel assembly of the present invention mounted to a conventional road vehicle; 
     FIG. 2 is a rear elevational view of the hi-rail wheel assembly in a retracted position; 
     FIG. 3 is a rear elevational view of the hi-rail wheel assembly in an extended position; 
     FIG. 4 is an exploded view of the hi-rail wheel assembly of the present invention; 
     FIG. 5 is a side elevational view of an upper link plate of the hi-rail wheel assembly; 
     FIG. 6A is a side elevational view of a lower link plate of the hi-rail wheel assembly; 
     FIG. 6B is a sectional side elevational view of the lower link plate as illustrated in FIG. 6A taken along the lines  6 B— 6 B; 
     FIG. 7A is a side elevational view of a cam of the hi-rail wheel assembly, and 
     FIG. 7B is a sectional side elevational view of the cam as illustrated in FIG. 7A taken along the lines  7 B— 7 B. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Looking at FIG. 1, a conventional road vehicle  10  having a pair of rear tires  18  and a pair of front tires  19  is illustrated utilizing an attached hi-rail wheel assembly  12  of the present invention. The purpose of the hi-rail wheel assembly  12  is to allow the vehicle  10  to be able to travel on railroad tracks  14  as well as on conventional roadways. This is accomplished by attaching the hi-rail wheel assembly  12  to the base of the vehicle  10 . The hi-rail wheel assembly  12  can be moved into one of two positions: retracted (as illustrated in FIG. 2) or extended (as illustrated in FIG.  3 ). While driving on a roadway, the hi-rail wheel assembly  12  will be in the retracted position close to the base of the vehicle  10  such that the vehicle tires  18 ,  19  will make contact with the roadway. To change from roadway travel to travel on railroad tracks  14 , the hi-rail wheel assembly  12  is extended downward from the vehicle  10  so that the railway wheels  16  will make contact with the railroad tracks  14  (see FIG.  3 ). Conventionally, when a -rail wheel assembly  12  is operated on the railroad tracks  14 , the front set of vehicle tires  19  will be elevated from the railroad tracks  14  while the rear set of vehicle tires  18  will make contact with the railroad tracks  14  so as to propel the vehicle  10  along the railroad tracks  14 . The object of this invention, therefore, is to control the elevation of the rear vehicle tires  18  making contact with the railroad tracks  14 . As a result, in a conventional hi-rail assembly where the front vehicle tires  19  are elevated above the railroad track  14 , the present invention would solely be used with the rear vehicle tires  18 , although the invention could be used interchangeably with front vehicle tires  19  as well as rear vehicle tires  18  as desired by the user. 
     FIGS. 2 and 3 illustrate the hi-rail wheel assembly  12  connected having a frame  20  that is attachable to the vehicle  10  (not illustrated in FIG. 2 or  3 ). Connected to each end of the frame  20  is a pair of coincidentally spaced pivotal links, the first pair labeled  22 ,  23  and the second pair labeled  80 ,  82 . Each pair of pivotal links  22 ,  23  and  80 ,  82  includes frame pin apertures  17  (seen in FIG. 5) that are designed to engage a frame pin  21  that joins each pair of pivotal links  22 ,  23  and  80 ,  82  with the frame  20 . Both pairs of pivotal links  22 ,  23  and  80 ,  82  are additionally connected to an axle tube  32 , and are aligned and operate in a plane parallel to the axle tube  32 . Since both pairs of pivotal links  22 ,  23  and  80 ,  82  operate in a plane parallel to the axle tube  32 , none of the pivotal links  22 ,  23 ,  80 , or  82  protrude outwardly to any significant extent beyond the frame  20  of the vehicle  10  and parts associated therewith. 
     FIG. 4 shows an exploded view of the hi-rail wheel assembly  12  of the present invention. 
     The first set of pivotal links includes first pivotal link  22  having an upper link plate  24  and a lower link plate  26 , and second pivotal link  23  having an upper link plate  25  and a lower link plate  27 . Each lower link plate  26 ,  27  is connected via a block pin  28  to a block  30  that is attached to the axle tube  32  and serves as a means for holding the axle tube  32 . Similarly, the second set of pivotal links includes first pivotal link  80  having an upper link plate  84  and a lower link plate  88 , and second pivotal link  82  having an upper link plate  86  and a lower link plate  90 . Each lower link plate  88 ,  90  is connected via a second block pin  92  to a second block  94  that is welded to the axle tube  32  at the end opposite of the first block  30 . 
     Inside of the axle tube  32  is an axle  33  (illustrated in FIG.  4 ), and a railway wheel  16  is attached at each end of the axle  33  such that the axle  33  will freely rotate within the axle tube  32  to control the rotation of the railway wheels  16 . The railway wheels  16  engage the ends of the axle  33 ; and each railway wheel  16  is secured to the axle  33  via a railway wheel nut  31 . 
     A pair of hydraulic cylinder assemblies  34 ,  35  are provided to actuate the pivotal links  22 ,  23  and  80 ,  82  to swivel. The first hydraulic cylinder assembly  34  includes a hydraulic cylinder  36 , a piston rod  38 , and a piston (not illustrated) positioned inside of the hydraulic cylinder  36  and attached to a first end of the piston rod  38 . A second end of the piston rod  38  is connected to a pair of mounting plates  40  using a mounting pin  42 . The mounting plates  40  are attached to the axle tube  32  at approximately the middle point of the axle tube  32 . The hydraulic cylinder  36  is pivotally attached between the upper link plates  24 ,  25  by a cylinder pin  44 . Further, the upper link plates  24 ,  25  are connected to the lower link plates  26 ,  27  via a plate connecting pivot  46 . The outward movement of the piston rod  38  relative to the hydraulic cylinder  36  will rotate the upper link plate  24  in a clockwise direction about the plate connecting pivot  46 , while the lower link plates  26 ,  27  will rotate in a counterclockwise direction about the plate connecting pivot  46 . Ultimately, the outward extension of the piston rod  38  will cause these pivotal links  22 ,  23  to occupy the extended position as illustrated in FIG.  3 . 
     The second hydraulic cylinder assembly  35  works as the first, and includes a hydraulic cylinder  37 , a piston rod  39 , and a piston (not illustrated) positioned inside of the hydraulic cylinder  37  and attached to a first end of the piston rod  39 . A second end of the piston rod  39  is also connected to the mounting plates  40  using a mounting pin  43 . The hydraulic cylinder  37  is pivotally attached between the upper link plates  84 ,  86  by a cylinder pin  45 . Further, the upper link plates  84 ,  86  are connected to the lower link plates  88 ,  90  via a plate connecting pivot  47 . The outward movement of the piston rod  39  relative to the hydraulic cylinder  37  will rotate the upper link plates  84 ,  86  in a counterclockwise direction about plate connecting pivot  47 , while the lower link plates  88 ,  90  will rotate in a clockwise direction about the plate connecting pivot  47 . Ultimately, the outward extension of the piston rod  39  will cause these pivotal links  80 ,  82  to occupy the extended position as illustrated in FIG.  3 . 
     Referring to FIG. 3, the first hydraulic cylinder assembly  34  is controlled from a source of fluid pressure not illustrated through a pair of flexible conduits  50 ,  52  connected to opposite ends of the hydraulic cylinder  36 . Flow of the fluid through the conduits  50 ,  52  is controlled by conventional valve means (not illustrated). As a result, in order to drive the piston rod  38  outwardly from the hydraulic cylinder  36 , fluid pressure is supplied through the first conduit  50  to the hydraulic cylinder  36  and fluid is discharged from hydraulic cylinder  36  through conduit  52  in a standard manner. If the hi-rail wheel assembly  12  needs to be in the retracted position (as in FIG.  2 ), fluid is supplied to the hydraulic cylinder  36  through conduit  52  and is discharged from the hydraulic cylinder  36  through conduit  50 . 
     Similarly, the second hydraulic cylinder assembly  35  is controlled from a source of fluid pressure not illustrated through a pair of flexible conduits  51 ,  53  connected to opposite ends of the hydraulic cylinder  37 . Flow of the fluid through the conduits  51 ,  53  is controlled by conventional valve means (not illustrated). As a result, in order to drive the piston rod  39  outwardly from the hydraulic cylinder  37 , fluid pressure is supplied through the first conduit  51  to the hydraulic cylinder  37  and fluid is discharged from hydraulic cylinder  37  through conduit  53  in a standard manner. If the hi-rail wheel assembly  12  needs to be in the retracted position (as in FIG.  2 ), fluid is supplied to the hydraulic cylinder  37  through conduit  53  and is discharged from the hydraulic cylinder  37  through conduit  51 . 
     In order to mechanically secure the pivotal links  22 ,  23 ,  80 , and  82  in their extended position as illustrated in FIG. 3, a means for locking the upper link plates  24 ,  25 ,  84 , and  86  and the lower link plates  26 ,  27 ,  88 , and  90  is provided. The locking means includes a first extended locking aperture  56   a  formed in the upper link plates  24 ,  25 ,  84 , and  86  (see FIG. 5) which, when disposed in the extended position, will correspond with a second extended locking aperture  56   b  formed in the lower link plates  26 ,  27 ,  88 , and  90  (see FIG.  6 A). A locking element  60  (see FIGS. 2 and 3) may then be inserted into these coinciding first and second locking apertures  56   a ,  56   b  to secure the elements of the pivotal links  22 ,  23 ,  80 , and  82  against relative movement while extended. 
     To prevent undesired dislodgment of the locking element  60  from the locking apertures  56   a ,  56   b , a locking shoulder  62  is secured to the upper link plates  24 ,  25 ,  84 , and  86  so that the locking element  60  may engage the locking shoulder  62 . After the locking element  60  is inserted into the locking apertures  56   a ,  56   b , an extension  63  of the locking element  60  may be swung underneath the locking shoulder  62  so as to prevent the outward dislodgment of the locking element  60 . 
     When the assembly  12  is operated to its retracted position, the locking means includes a first retracted locking aperture  58   a  formed in upper link plates  24 ,  25 ,  84 , and  86  that will align with a second retracted locking aperture  58   b  formed in the lower link plates  26 ,  27 ,  88 , and  90 . Subsequently, the locking element  60  may be inserted through the aligned first and second retracted locking apertures  58   a ,  58   b  to secure the lower link plates  26 ,  27 ,  88 , and  90  in position with the upper link plates  24 ,  25 ,  84 , and  86 . 
     As stated above, the hi-rail wheel assembly  12  may be in either a retracted position or an extended position. A problem commonly occurring with conventional railway wheel assemblies is that after a period of constant use in the extended position, the friction between the vehicle tires  18  and the railroad track  14  will cause wear on the vehicle tires  18 . Furthermore, to prevent misuse and malfunction of the hi-rail wheel assembly  12 , the hi-rail wheel assembly  12  must stay in the extended and locked position. As a result of the constant wear on, the vehicle tires  18 , the vehicle tires  18  will not have sufficient traction with the railroad tracks to run efficiently, which will reduce the capacity of the vehicle  10  to provide a propelling force on the railroad tracks  14 . 
     To improve the traction of the vehicle tires  18  on the railroad tracks  14 , each pivotal link  22 ,  23 ,  80 , and  82  is designed to receive a cam  68  (see FIG. 4) which will allow vertical adjustment for the hi-rail wheel assembly  12  such that the vehicle wheels  18  may be lowered onto the railroad tracks  14  to improve the traction. As illustrated in FIGS. 6A and 6B, each lower link plate  26 ,  27 ,  88 , and  90  is designed with a cam aperture  64  and a recessed cam shoulder  66  surrounding the cam aperture  64 . The diameter of the outer periphery of the recessed cam shoulder  66  is such that it may receive the cam  68 . 
     Looking at FIG. 7A, the cam  68  of the present invention has an eccentric aperture  70  for receiving the block pins  28 ,  92  through the cam aperture  64  of the lower link plates  26 ,  27 ,  88 , and  90  (illustrated in FIGS.  2  and  3 ). The eccentric aperture  70  is preferably positioned near the center of the cam  68 . Furthermore, six cam mounting bores  72  are placed along the outer periphery of the cam  68 . The cam mounting bores  72  are equally spaced along the outer periphery of the cam  68 , and are used to secure the cam  68  to the lower link plate  26 . 
     Looking at FIG. 7B, a sectional side view of the cam  68  illustrates the cam  68  being composed of a first disc  74  integrally connected to a second disc  76 . The first disc  74  has a diameter substantially equal to the diameter of the cam aperture  64 , and the second disc  76  has a diameter substantially equal to the diameter of the outer perimeter of the recessed cam shoulder  66 . Consequently, when the cam  68  engages one of the lower link plates  26 ,  27 ,  88 , or  90 , the first disc  74  will engage the cam aperture  64  and the second disc  76  will cover the recessed cam shoulder  66 . Moreover, the eccentric aperture  70  traverses both first and second discs  74 ,  76  of the cam  68  such that the eccentric aperture  70  will engage the block pin  28 ,  92  when the cam  68  engages the lower link plates  26 ,  27 ,  88 , and  90  (see FIG.  4 ). 
     Referring to FIG. 6A, a closer view of an example of the lower link plates  26 ,  27 ,  88 , and  90  of the current invention is illustrated having a plate connecting pivot aperture  75  and a cam aperture  64  for engaging the cam  68 . As stated above, the recessed cam shoulder  66  surrounds the cam aperture  64 , and the diameter of the recessed cam shoulder  66  is substantially equivalent to the diameter of the second disc  76  of the cam  68  such that the second disc  76  of the cam  68  may be inserted over the recessed cam shoulder  66 . Preferably, the diameter of the cam  68  is approximately 4.24 inches, and thus the diameter of the circle defining the outer periphery of the recessed cam shoulder  66  is approximately 4.25 inches. 
     The recessed cam shoulder  66  further includes a plurality of connecting apertures  78 . Looking at FIG. 4, the cam  68  is attached to the lower link plate  26  via a connecting means  81 , such as a screw or a bolt, when the cam mounting bores  72  are aligned with the connecting apertures  78  such that the connecting means  81  may be inserted through both the cam mounting bore  72  of the cam  66  and the connecting apertures  78  of the lower link plate  26 . Ideally, the diameter of each connecting aperture  78  and each cam mounting bore  72  is 0.375 inches. Since the second disc  76  engages the cam aperture  64 , the eccentric aperture  70  of the cam  68  may be rotated within the open area defined by the circular cam aperture  64 . 
     The distance between the railroad track  14  and the frame  20  is thereby determined by the mounted position of the eccentric aperture  70  within each lower link plate  26 ,  27 ,  88 , and  90 . As the cam  68  is rotated within each lower link plate  26 ,  27 ,  88 , and  90 , the position of the block pins  28 ,  92  with respect to the frame  20  will be adjusted according to the radial position of the eccentric aperture  70 . Furthermore, to evenly position the hi-rail wheel assembly  12 , the cams  68  in the first pair of pivotal links  22 ,  23  will be rotated in one direction, while the cams  68  in the second pair of pivotal links  80 ,  82  will be rotated in the opposite direction so that the position of the eccentric apertures  70  in the first pair of pivotal links  22 ,  23  will mirror that of the position of  20  the eccentric apertures  70  in the second pair of pivotal links  80 ,  82 . 
     Preferably, there are six mounting bores  72  in the cam  68  and twelve connecting apertures  78  in the shoulder  66 . Accordingly, the cam  68  can be rotated so that the mounting bores  72  will align with the desired connecting apertures  78  at several different points around the circumference of the recessed cam shoulder  66  to provide various distances between the frame  20  and the axle tube  32 . Such an arrangement subsequently provides various degrees of connection between the vehicle wheels  18  and the railroad tracks  14 . 
     In operation, when new vehicle tires  18  are used, the cam  68  will be mounted such that the eccentric aperture  70  is at the highest point of the rotation so as to provide the greatest distance between the axle tube  32  and the frame  20 . However, as wear begins to deteriorate the traction between vehicle tires  18  and the railroad tracks  14 , the position of the cam  68  may be rotated such that the position of the eccentric aperture  70  moves the hi-rail assembly  12  such that the distance between the axle tube  32  and the frame  20  will be reduced. As a result, the vehicle wheels  18  will again make contact with the railroad tracks  14  to improve the traction and allow the vehicle wheels  18  to efficiently propel the hi-rail wheel assembly  12  on the railroad tracks  14 . 
     Thus, although there have been described particular embodiments of the present invention of a new and useful HI-RAIL WHEEL ASSEMBLY FOR IMPROVED TRACTION, it is not intended that such references be construed as limitations upon the scope of this invention except as set forth in the following claims.