Abstract:
A railcar positioning system operable as either an indexer or progressor is disclosed which includes a pair of spaced trackside railcar movers positioned outside and parallel to the rails of a railroad track. Each railcar mover includes a spaced trackside guideway located next to one of the railway rails, a plurality of spaced connected dog carriages mounted for operation together in the guideway, each dog carriage carrying a pusher dog mounted on the carriage, a reciprocating hydraulic cylinder associated with the plurality of spaced, connected dog carriages. A hydraulic power unit is connected to operate each of the cylinders individually or together and a control system is associated with the power unit for controlling the operation of the positioning system such that said positioning system may be optionally operated as an indexer or as a progressor.

Description:
CROSS-REFERENCED TO RELATED APPLICATIONS 
       [0001]    Not applicable 
       STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0002]    Not applicable 
       BACKGROUND OF THE INVENTION 
       [0003]    I. Field of the Invention 
         [0004]    The present invention relates generally to trackside railway car handling equipment for positioning railcars along a track for loading or unloading operations. More particularly, the present invention relates to train positioning systems that are operable either as indexers or progressors and which operate against the bogey frames of rail cars. 
         [0005]    II. Related Art 
         [0006]    Freight-hauling railway cars need to be precisely positioned proximate freight or cargo handling equipment during loading and unloading operations. Freight in the form of bulk cargo such as grain is typically loaded or unloaded with reference to stationary freight handling equipment such as chutes and conveyor equipment situated at fixed locations above or in pits beneath a specific portion of the track. Railcars for transporting grain or other such finely divided dry bulk agricultural commodities may be covered and designed with a plurality of spaced bottom discharge hopper bins or chutes accessing the main cargo storage volume. The chutes are closed by capstan-operated rack and pinion bottom closure gate systems. 
         [0007]    In the loading and discharge operations, a connected engine roughly positions one end of a string of cars to be loaded or unloaded beneath or above the appropriate equipment at the desired fixed location. Because locomotives are not well suited for precisely positioning individual cars or even strings of cars along a railroad track, positioning devices known as train movers or positioners are located at fixed stations along the track. The positioning devices generally employ heavy pushing members known as railcar-engaging “dogs” to move the cars into position. 
         [0008]    Positioning devices are generally classified in the industry as “indexers” or “progressors”. Indexers may employ dogs carried by a pair of carriages operating along indexer tracks on built-in guideways located on opposite sides of associated track rails. Indexers are designed so that the carriages and associate dogs on both sides of the track are coordinated to operate together in unison to engage and move a car or string of cars along the track. Thus, in indexer type bogey frame-engaging positioning devices, both dogs of a pair of dogs spaced on opposite sides of the track are caused to engage the bogey frame during the same stroke to thereby provide a balanced force by pushing against both of the spaced sides of the truck bogey frame simultaneously. 
         [0009]    Progressors designed to operate against bogey frames also operate along rails in built-in guideways on the outside of each of the spaced rails of a track with dogs that operate along each of the guideways spaced along the track. Rather than operating simultaneously against both sides of a bogey frame to move a car or string of cars, the dogs of a progressor are operated alternately, to sequentially engage a bogey frame so as to “hand off” the car or string of cars alternating between dogs on opposed sides of the track. 
         [0010]    Using either type system an entire string of connected cars may be advanced with precision and loaded or unloaded, one car at a time. As with the indexer system, the progressor can be stopped at any point in the operating cycle when the desired position is reached. 
         [0011]    Operation of car handling equipment in each of the modes described above has certain advantages and either may be desirable depending on operational circumstances and conditions. As indicated, operation as an indexer advantageously provides a balanced side-to-side force on the bogey frame and enables the total force of two dog carriage systems to be applied at once so that heavier loads may be moved. This also enables a balanced force to be applied against the bogey frames of lightly loaded cars which avoids a possible tipping situation which may occur when force is applied to one side only. However, because indexers operate the dogs together, after a power stroke, both dogs must be retracted and the next bogey frame found before the next power stroke can be started. Operating both dogs together on the power stroke necessarily slows the speed of progression. Progressor type operation can provide multiple power strokes in rapid succession by alternating carriage operation in a hand-off fashion, however, the applied force is limited to that of a single dog carriage and the force of that dog is operated against only one side of the bogey frame. 
         [0012]    Heretofore, such railcar handling equipment has been constructed as dedicated to operation either as an indexer or a progressor and it would provide a distinct advantage and answer a definite need in the art if such a system could handle railcars in either manner. 
       SUMMARY OF THE INVENTION 
       [0013]    By means of the present invention there is provided a railcar positioning system operable either in an indexing mode or as a progressor. The system includes left and right track side indexing or railcar-moving arrangements positioned just outside and parallel to flanking the rails of a conventional railroad track. Each of the left and right track side arrangements includes a guideway which extends along the track and carries a plurality of spaced sequentially connected dog carriages mounted for operation in the guideway, each dog carriage is provided with a vertically pivoting pusher dog mounted on the carriage. Each arrangement is operated by a double-acting hydraulic cylinder which is designed to reciprocally move the arrangement including the several sequential dog carriages, either in an extend or retract direction. Each of the tracking arrangements also includes its own hydraulic power unit and each of the operating cylinders is provided with an individual, separately operable control and valving system including multi-position hydraulic control valve which enables individual, separate operation. The control and valving systems are also integrated to provide coordinated action between the two hydraulic cylinders such that the combined system may be operated as an indexer or as a progressor. 
         [0014]    In one illustrative embodiment, each of the car-moving arrangements includes three dog carriages sequentially spaced by connecting rods. Each dog carriage rides on a rail and carries a dog that is spring-biased in the raised position and each guideway includes downing devices for automatically downing and latching devices for automatically latching all three dogs when each cylinder is fully extended. The dogs are downed using cam-operated ramping systems and spring-biased latching mechanisms which capture latch wheels attached to the dogs. Thus, each dog carriage latch mechanism has a pivoting spring-operated catch device that captures an associated latch wheel attached to a corresponding dog. The cylinders can be fully retracted with the dogs locked down. Dog carriage latch tripper flags are provided that pivot the catches and open the latches and allow the dogs to pop up when the carriages are advanced from the fully retracted position. 
         [0015]    In the detailed embodiment, the dogs utilized are vertically operating low dogs which push against a lower portion of the sides of the bogey frames of cars being moved by the positioning system of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]    In the drawings wherein like numerals are utilized to designate like parts throughout the same: 
           [0017]      FIG. 1  is a schematic perspective fragmentary view of a pair of spaced left and right railcar indexing arrangements in accordance with the invention with parts broken for convenience; 
           [0018]      FIG. 2  is a slightly enlarged partial top view of the arrangement of  FIG. 1 ; 
           [0019]      FIG. 3  is a greatly enlarged fragmentary view showing a low dog addressing a bogey frame of a railcar truck; 
           [0020]      FIG. 4A  is a greatly enlarged fragmentary view of a dog carriage showing a dog in a raised position; 
           [0021]      FIG. 4B  is a view similar to  FIG. 4A  showing the dog in a downed, latched position; 
           [0022]      FIG. 5  is a greatly enlarged fragmentary view of a dog carriage showing a latch assembly exploded; 
           [0023]      FIG. 6  is a greatly enlarged fragmentary view of a part of a guideway showing an exploded view of a dog latch tripper flag; and 
           [0024]      FIGS. 7A and 7B  depict a typical hydraulic diagram of a control system suitable for use with the system of  FIGS. 1-6 . 
       
    
    
     DETAILED DESCRIPTION 
       [0025]    The following detailed description of the present invention describes the invention in terms of being a versatile system able to move railcars in either of two modes, i.e., as an indexing system by operating the dogs on either side of the track in pairs to push against opposite sides of a common bogey frame in unison or, alternatively, to have the system operate sequentially as a progressor to provide continuous motion using right and left dogs to push against one and then the other side of a bogey frame in a hand-off mode. In either mode, the system may be stopped anywhere in the operating cycle to allow loading or unloading operations to take place. It will be understood that the system described is intended to present a example of the inventive concept and is not intended to limit the scope of the invention in any manner as variations within the scope of the inventive concept may occur to those skilled in the art. 
         [0026]      FIGS. 1 and 2  depict schematic perspective views, with parts broken for convenience, of left and right railcar indexing arrangements of a train positioning system in accordance with the invention. The system includes spaced left and right train moving or indexing arrangements  20  and  22 , respectively, which are positioned just outside and parallel to a pair of railroad tracks (not shown) in a well known manner so that one car-moving arrangement is located just outside each rail. The left and right indexing arrangements are generally identical opposed systems which may be slightly offset from each other. The left positioner  20  includes an elongated guideway or indexer track at  24  (shown in broken segments for clarity and convenience) which houses the components of a railcar-moving indexer system designed to operate reciprocally along the guideway  24 . The components of the railcar-moving arrangement include left hydraulic cylinder  26  with associated rod  28 . Three spaced dog carriages are provided including a cylinder carriage  30 , a mid carriage  32  and an end carriage  34 , which carry vertically pivoting low dog pushing devices shown at  36 ,  38  and  40 , respectively. The dog carriages are connected at fixed spacings by mechanical linkages and connecting rods as at  42  and  44  in a well known manner. The dog carriage  36  is connected to the cylinder rod  28 . 
         [0027]    The dogs are spring-biased to a raised or pushing position and must be forced or pushed down to be lowered. Devices are provided to automatically lower and retain the corresponding dogs in a lowered or dropped position under certain circumstances. These include a latch on each dog carriage associated with a latch wheel and a cam operated mechanical arrangement which ramps an associate dog down. An associated dog latch tripper flag is provided to unlatch the dog, as will be described. 
         [0028]    The indexer further includes dog down proximity sensors  46 ,  48 ,  50 , one associated with each dog carriage travel space. The end of the left indexer further includes a full extend dog lock down and hand off proximity sensors at  52 ,  54 ,  56 . 
         [0029]    Dog ramp down devices are shown at  58 ,  60 ,  62  and dog tripper flags are shown at  64 ,  66 ,  68 . The operation of these devices will be explained. A full retract proximity sensor is included at  70 . 
         [0030]    The right indexer  22  is positioned in spaced parallel relation to the left indexer and is of like design so that it is generally an opposed or mirror image of the left indexer. It includes a right hydraulic cylinder  126  with rod  128 . Right indexer dog carriages are likewise shown successively at  130 ,  132 ,  134  carrying respective dogs  136 ,  138 ,  140  with carriage connectors shown at  142 ,  144 . The right indexer has corresponding dog down proximity sensors  146 ,  148 ,  150  and full extend and dog lock down proximity sensors  152 ,  154 . Dog ramp down devices are shown at  158 ,  160 ,  162  and corresponding tripper flags  164 ,  166 ,  168 . 
         [0031]      FIG. 3  depicts a railcar truck carriage, generally  200  including a pair of spaced axels journaled in a bogey frame  204 . Flanged wheels  206  ride on spaced rails  208 . A raised low dog  38  is shown addressing bogey frame  204  from dog carriage  32  as it rides on carriage indexer track  210 . 
         [0032]      FIGS. 4A and 4B  depict greatly enlarged fragmentary views showing a dog in the raised and downed, latched position, respectively. The dog  38  is maintained in a raised position by a tension spring (not shown) unless forced down, as will be explained. In the figures, a dog ramp down device  60  and a dog latch device  220  cooperate to lower and latch the dog  38 . 
         [0033]    The ramp down device  60  includes a ramp down cam wheel  230  which is disposed to contact a follower extension  232  which is designed to contact an associated ramp down cam wheel. The dog  38  further includes an attached lock down or latch wheel  234  which cooperates with a spring-operated dog latch member  236  to latch the downed dog in the lowered position, as shown in  FIG. 4B . A dog tripper flag  68  is also shown, which operates to release the latch on the next consecutive dog. 
         [0034]      FIG. 5  depicts a greatly enlarged exploded view of a latch assembly for a dog latch member  236  that includes a tube  246  with attached mounting bracket  242 , a latch shaft  244  and shaft collar  246  which is keyed to shaft  244  and includes attached lever  248  and biasing tension spring  250 . The spring  250  puts rotational torque on the shaft  244  to maintain the dog latch member  236  in the upright or latched position. The latch assembly is fixed to the dog carriage by fasteners  252 . 
         [0035]    A dog tripper flag assembly as at  68  is shown exploded in  FIG. 6  and includes a base member  260  with base tube  262  and gusset member  264 . A tube mounted flag member is provided at  266  with mounting shaft  268  that is carried in base tube  262  by bolt  270  with washer  272  and nut  274 . A spring-biased collar is provided at  276  with tension spring  278  and a bolt. Washers are provided at  280 ,  282 ,  284 . As assembled, the spring  278  is fastened between the gusset  264  at  286  and the collar  276 . In this manner, a dog latch member as at  236  passing a latch tripper flag during a cylinder extension will encounter the resistance produced by the tripper flag spring and will pivot the corresponding dog latch member counter-clockwise, opening the latch, releasing the dog latch wheel thereby allowing the related dog to pop up. A latch member encountering a latch tripper flag during a retraction stroke will push the flag aside and the dog will remain latched. 
         [0036]      FIGS. 7A and 7B  depict a diagram of a hydraulic system suitable for operating the railway car handling system of the invention. The hydraulic system includes separate hydraulic power systems for the left and right indexer arrangements which enable them to operate separately or together. The left indexer system includes a hydraulic pump system  300  operated by a motor  302 . The pump system has outlet connections to high pressure feed lines  304  and  306  which include in-line filters  308 ,  310  with check valve by-pass line filters  312 ,  314 ; respectively. Connection to a return or drain line  320  for lines  304 m,  306  are shown and include line  322  controlled by drain solenoid valve  324  and line  326  controlled by solenoid drain valve  328 . Check valves are located at  330 ,  332  and a general dump drain valve for both lines is shown at  334  on line  336  with associated pressure gauge  337 . An additional pressure gauge is shown at  338 ,  339 . 
         [0037]    The operation of the left indexer cylinder  26  is controlled by three-positioned valve  340  within the dashed line at  342 . Valve  340  includes an internal drain to dashed drain line  344  which connects with a common drain line  346 . Valve  340  has extend, neutral and return positions and connects high pressure line  304 / 306  with an extend line  348  and retract line  350  which, in turn, connect with cylinder  26  at the blind and rod ends, respectively. As return or drain line is shown at  352  which connects the valve  340  with return line  320  via line  354 . The system further includes over pressure relief valves  356  and  358 , the latter of which also has an internal drain connection to line  360 . Check valves are incorporated at  362 ,  364 . 
         [0038]    The hydraulic supply system further includes an electric hydraulic oil heater  370 , operated by a temperature switch shown in the box at  372  along with a hydraulic sump liquid level switch  373  and a left system shutoff valve is shown at  374  and a suction or inlet filter is shown at  376 . A filter is shown in return line  320  at  378 . 
         [0039]    Similarly, the right indexer system includes a pumping system  400  operated by connected motor  402 . Pump high pressure outlet lines are shown at  404 ,  406 . Inline filters are shown at  408 ,  410  with respective spring-loaded bypass check valves  412 ,  414 . Connections to drain line  320  for lines  404 ,  406  include line  322  with solenoid drain valve  424  connected to high pressure line  404  and line  426  with solenoid drain line  428  connected to line  406 . Check valves are located at  430 ,  432  and a general dumper drain valve for both lines is shown at  434  on line  436 , which is also connected to a pressure gauge  437 . Other pressure gauges are shown at  438 ,  439 . 
         [0040]    The operation of right indexer cylinder  126  is controlled in the same fashion as left cylinder  26  and the system includes a  3 -position valve  440  in dashed lines  442  with an internal drain to line  444  which also connects to a common drain line  346 . The  3 -position valve also connects high pressure line  404 / 406  with extend line  448  and a retract line  450  which connect to respective blind and rod end ports of the cylinder  126 . As return or drain line is shown at  452  which connects with the common drain lines  354 ,  320 . The system also includes over pressure relief valves  456 ,  458 . Valve  458  includes drain line  460  and check valves are shown at  462 ,  464 . A right system shut-off valve is shown at  474  with corresponding intake filter  476 . 
         [0041]    A common connecting high pressure line is shown at  480  to balance the pressure between the lines  304  and  404  when the cylinders are operated together. 
         [0042]    In operation, the system is started with the cylinders fully retracted and the dogs latched down. When the system is activated, both cylinders are extended and the corresponding dog latch tripper flags are encountered by corresponding latch members which cause the latch members to rotate and release the dog latch wheels and allow all of the dogs to pop up. When an advancing dog encounters, is pushed down by, moves behind, and pops up behind a bogey frame, that corresponding indexer may be used to move the car or string of cars as a progressor and haul off to the next dog in the opposite indexer, etc. in a well-known manner or the other indexer can continue to extend until both opposite dogs encounter are pushed down by and pop up behind the same bogey frame and the system is operated as an indexer. 
         [0043]    It should be apparent that the power stroke, in any event, occurs when the cylinders are in the retraction mode only and accordingly, the retract mode is operated at a much higher, possibly  2400  psi pressure vs possibly  850  psi for an extend stroke. 
         [0044]    Of course, the diameter, and thus the area, of the cylinders and rods, along with the operating pressure, will determine the total force applied or available for an extend or retract stroke. 
         [0045]    In the event that the force necessary to move a car or string of cars in the progressor mode exceeds the safe level for a low dog against one side of a bogey frame, the system may require switching to an indexing mode where twice the pulling force is available using dogs from both left and right indexers against the bogey frame. This also balances the force against the bogey frame preventing any tendency of a corresponding truck to derail. 
         [0046]    The left and right indexers also may be offset by a small distance to compensate for any showing of any encountered truck bogey frames which shift due to a progressor dog pushing against one side of the frame alone. 
         [0047]    This invention has been described herein in considerable detail in order to comply with the patent statutes and to provide those skilled in the art with the information needed to apply the novel principles and to construct and use embodiments of the example as required. However, it is to be understood that the invention can be carried out by specifically different devices and that various modifications can be accomplished without departing from the scope of the invention itself.