Patent Publication Number: US-7909294-B2

Title: Modular railroad switch stand

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to switch stands for railroad switches, and in particular to switch stands which permit trailing operation of railroad switches. 
     2. Description of the Related Art 
     On railroad tracks, railroad switches have been provided to permit trains to transfer from a track or set of rails to another based on the position of a pair of linked tapering rails or points. Railroad switches have also been referred to as turnouts. The switching capability has often been provided through an electric motor driven switch which included a motor-driven throw bar or the like to throw switch points to control the switching of rolling stock. Motor-driven switching worked well for main line and transit operations. However, in rail yard applications additional switching features were needed. It has been common for yard switch operations to include manual operation of the switches by yard personnel. 
     For accident prevention and safety purposes, it has been common practice to provide switch stands with a mechanism to lock the switch in a desired setting and to indicate that position. However, it has also been desirable that the switches also permit what is known as trailing, where rolling stock such as a car or engine could go through the switch from either of two merging sets of rails onto a single set of rails without having to change the set position of the switch. 
     In trailing operations, the force of the wheels changed the position of the points to the proper position for the switch point change to occur. If the switch stand was locked, an attempt at trailing would cause damage the switch and stand, and possibly even worse. For this reason, some forms of switch stands were provided with what was known as a semi-automatic capability. The stand was motor-driven and kept in a normal position, but was provided with a separate unit that permitted trailing. 
     For a switch machine with trailing capability, passage of rolling stock through the switch in the reverse or trailing direction caused the switch to be thrown automatically, that is, without the time delay of a manual switch operation. 
     So far as is known, two other types of switch stands have been commonly used for railroad switches. One type of switch was manually operable or changeable. Manual switch stands were provided with locks for safety purposes to set and retain the switch in its desired position or setting. However, if trailing operations were attempted through a locked switch, damage resulted as has been mentioned. It was also expensive and time consuming to unlock and then manually change the position of a manual switch temporarily for trailing to occur. However, safety considerations required that the switch be kept locked at all other times at its desired or normal setting. 
     The other type of switch stand has been the remote controlled or automatic switch stand which allowed the switch stand to be locked from a remote control site. These switch stands were even more costly than semi-automatic stands. Estimated costs of a single remote control switch stand have been about fifteen thousand dollars each. With the number of switch stands present in a railroad system, the capital investment costs can be seen to be considerable. 
     SUMMARY OF INVENTION 
     Briefly, the present invention provides a new and improved switch stand for operating a railroad switch in a trailing operation moving points of the railroad switch from a set position to permit passage of railroad rolling stock through the switch in the trailing operation. The switch stand includes a housing mounted adjacent the railroad switch, and a shaft mounted in the housing. The shaft is connected to the railroad switch and is movable from a normal position and rotatable in response to movement of the railroad switch when contacted by a wheel of the rolling stock in a trailing operation. A contact block member of the switch stand is mounted in the housing with the shaft. The contact block member moves along a longitudinal axis of the shaft, but is restrained against rotational movement with respect to the shaft and housing as the shaft rotates. 
     A roller guide member of the switch stand is rotatably mounted on the contact block member. A plate member fixedly mountable with the shaft for rotational movement and having a camming surface along a portion thereof engaging the roller guide causes rotational movement of the shaft with respect to the housing in response to movement of the railroad switch when contacted by a wheel of the rolling stock in a trailing operation. 
     A resilient member urges the camming roller against the guide shaft of the plate member to return the plate member to a position causing the switch to return to the normal position on removal of contact of the rolling stock wheel against the switch. A top cap is mounted with the shaft for rotational movement therewith and has control detents formed in it. 
     A control lever fixedly mounted with the shaft is selectively movable into engagement with the top cap in one of the control detents to interconnect the top cap and the shaft for rotational movement during trailing operation of the switch stand. 
     The present invention thus provides a modular semi automatic high switch stand for a railroad turnout in which the base is a removable piece bolted to a main body of the switch stand. Thus, when the base is damaged or broken it may be changed easily and quickly. Further in the event that it may be necessary for the base to be removed for some reason, the main body remains mounted in place on the ties. The modular switch stand has a pin eye or socket that has the exact radius to meet the throw specification that must be one and the same for the two switch points of a turnout. The pin eye is made to match with an adjusting rod in order to properly adjust the switch points. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic view of a railroad track switch with a switch stand according to the present invention. 
         FIG. 2  is a schematic view of the operation of the switch and portions of the switch stand of  FIG. 1 . 
         FIG. 3  is a front elevation view of a switch stand according to the present invention. 
         FIG. 4  is a side elevation view of the switch stand of  FIG. 3 . 
         FIG. 5  is an exploded view of portions of the switch stand of  FIGS. 3 and 4 . 
         FIG. 6  is a view taken along the lines  6 - 6  of  FIG. 3 . 
         FIGS. 7 and 8  are vertical cross-sectional views of a housing of the switch stand of  FIG. 3 . 
         FIG. 9  is a cross-sectional view taken along the lines  9 - 9  of  FIG. 8 . 
         FIG. 10  is a vertical cross-sectional view of a base of the switch stand of  FIG. 3 . 
         FIG. 11  is a side elevation of the shaft of the switch stand of  FIG. 3 . 
         FIG. 12  is a plan view of a contact block of the switch stand of  FIG. 3 . 
         FIGS. 13 and 14  are side elevation views of the contact block of  FIG. 12 . 
         FIG. 15  is a plan view of a plate member of the switch stand of  FIG. 3 . 
         FIG. 16  is a cross-sectional view along the lines A-A of  FIG. 15 . 
         FIG. 17  is a bottom view of the plate member of  FIG. 15 . 
         FIG. 18  is an elevation view, taken partly in cross-section, of a cap member and control lever of the switch stand of  FIG. 3 . 
         FIG. 19  is a horizontal cross-sectional view of a portion of the structure of  FIG. 18 . 
         FIGS. 20 and 21  are side elevation views of indicator panels of a switch stand according to the present invention. 
         FIG. 22  is a side elevation view, taken partly in cross-section, of an alternate embodiment, a low switch stand, according to the present invention. 
     
    
    
     To better understand the invention, a detailed description of certain embodiments is shown in the drawings for illustrative purposes but not as limitations, as further described herein. In certain of the Figures, components are illustrated in somewhat enlarged views from other Figures so that structural features thereof may be more readily seen. 
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In the drawings, the letter S designates generally a switch stand according to the present invention. The switch W is shown in  FIG. 1  in what is known as a set position. In the set position, the switch W allows railroad rolling stock to move as indicated by an arrow  30  from rails  32  and  34  onto rails  36  and  38  of what is known as the straight track. The switch W can be moved manually using the switch stand S to an alternate position and locked to allow movement, as indicated by an arrow  40 , of rolling stock from rails  32  and  34  onto rails  42  and  44  of what is known as diverging track. In the alternate position, switch point  46  is in engagement with rail  32  and switch point  48  is spaced from the rail  44  to guide the rolling stock wheels from rails  32  and  34  onto rails  42  and  44 , respectively. 
     As will be set forth below, the switch stand S permits operating the railroad switch W in a trailing operation to allow rolling stock to move from the diverging track onto rails  32  and  34  when the switch W is in the set position shown in  FIG. 1 . In the trailing operation, switch points  46  and  48  of the railroad switch W move from the set position ( FIG. 1 ), even though the switch is locked in that position, to permit passage of railroad rolling stock through the switch W. 
     The switch stand S of the present invention is shown schematically in  FIG. 1 , while structural features are shown in other figures of the drawings. As shown in  FIG. 1 , the switch stand S is connected to the switch points  46  and  48  of the switch W by a linkage including a connecting rod  50 . The connecting rod  50  moves along its longitudinal axis as indicated at  52  to adjust the position of the switch points  46  and  48 . The connecting rod  50  is connected in the conventional manner to a conventional eye pin which is mounted on a socket  60  located at a lower end  62  of a shaft T. As the connecting rod  50  moves longitudinally and the position of the switch points  46  and  48  change, the shaft T rotates, as indicated schematically in  FIG. 2 , between positions  54  and  56  based on the limits of longitudinal movement of the connecting rod  50 . As mentioned above, the switch W permits trailing operations when wheels of rolling stock contact the switch points in transitioning from rails  42  and  44  ( FIG. 1 ) to rails  32  and  34 . The shaft T is also rotatable through movement of the connecting rod  50  in response to movement of the switch points  46  and  48  of railroad switch W when contacted by wheels of the rolling stock in the trailing operation. 
     The shaft T is preferably a heat treated steel having the sleeve or socket  60  in the lower portion  62  for connection in the conventional manner to the pin eye of the known type. As has been set forth, the pin eye is connected by the connecting rod  50  to the switch W. If desired, the sleeve  60  may be provided with a groove or slot with an inner flat side to provide a positional reference to maintain proper distance or spacing between the rotational axis of the shaft T and the rotational connection of the pin eye. This is done to provide correct spacing and rotational movement of the shaft T and the end of the connecting rod  50 , in order to have the correct throw in the switch points  46  and  48 . 
     The shaft T of the switch stand S of the present invention is located in a housing H mounted adjacent the railroad switch W, extending upwardly through ports or passages  62  and  64  formed in interior body walls  66  and  68  of the housing H. The shaft T is freely rotatable about its longitudinal axis with respect to the housing H, and bearings  70  and  72  are mounted in ports  62  and  64  to provide for freedom of such rotational movement. The shaft T in addition has reduced friction against rotation when the switch stand S is operated by hand. The bearings  70  and  72  reduce such friction against rotation so that the force required to be applied by an operator during manual operation is reduced. The shaft T is connected to the railroad switch W and is movable from a normal position as indicated at  34  ( FIG. 2 ) with the switch W in the set position ( FIG. 1 ). 
     The housing H according to the present invention is formed of two component members or parts: an upper housing structure U which contains the operating mechanism of the switch stand S; and a base or mounting plate E for connecting the upper housing structure U to railroad crossties or other support structure. With the operating mechanism contained in the housing H, the switch stand of the present invention is modular. The upper housing structure U is connected by bolts  52  ( FIG. 6 ) or other suitable connectors to the base plate E, and the base plate is connected by spikes, bolts or the like as indicated at  54  to the railroad crossties or other support structure. The housing H can thus be disconnected into two separate housing components. In service, lower portions of switch stands have often been damaged by throw bars, hammers or the like during construction, maintenance or other activities during everyday usage. On such occasions, with a unitary housing the complete switch stand required replacement. With the present invention, it is only required to remove and replace the base plate E in the event of such damage. The structure and mechanisms of the upper housing H need not be replaced. 
     The modular switch stand S shown in  FIGS. 3 and 4  according to the present invention is what can be regarded as a high or tall stand. It should be understood, however, that the modular switch stand according to the present invention can take the form of a low stand ( FIG. 22 ), as will be set forth. 
     A contact block member B ( FIGS. 5 ,  12 ,  13  and  14 ) of the switch stand S is mounted with the shaft T in an upper chamber  76  of the housing H above the wall  68 . The contact block member B has a central sleeve or opening  80  through which the shaft T passes. The sleeve  80  is sized so that the shaft T freely moves for rotation along its longitudinal axis in the contact block member B. The contact block member B has outwardly extending guide finger or tongue members  82  formed along an outer side wall  84  which are fitted into slots  86  ( FIGS. 7 ,  8  and  9 ) formed between guide channels  87  and  88  formed on each of opposed inner side walls  90  and  92  in the upper chamber  76  of the housing H. The contact block member B thus is capable of movement within the housing H along the longitudinal axis of the shaft T. The contact block member B also permits rotation of the shaft T with respect to the housing H. However, the contact block member B is restrained by the fingers  82  in the slots  86  against rotational movement in conjunction with the shaft T as the shaft T rotates. 
     The switch stand S of the present invention includes one or more roller guide members R ( FIGS. 12 ,  13  and  14 ) which are mounted for rotational movement on shafts  96  formed on the contact block member B. The shafts  96  are formed extending outwardly ( FIG. 12 ) from outer side wall  84  at positions peripherally spaced from finger members  82 . The roller guide members R are urged upwardly by a resilient force-exerting member M ( FIG. 3 ,  4  and  5 ), typically a coiled spring  100 , into contact with a curved camming surface  98  formed on a lower circumferential portion or skirt  102  of a plate member P. 
     The spring  100  is positioned in the chamber  76  of the housing H between the wall  68  and a lower surface  104  within a pocket  106  formed in a lower portion of the contact block member B exerting a force on the contact block member urging the roller guide members R into engagement with the camming surface  98 . The size and contouring of the camming surface  98   a  are established so that the roller guide members R can allow the plate member P to travel over the roller members R from an upper or rest position  98   a  slightly less than one-eighth turn or 45° to a location  98   b  or  98   c  as the case may be. 
     Such movement occurs in response to movement of the shaft T due to forces exerted by the wheels of the rolling stock on the switch points  46  and  48  during a trailing operation. On removal of such wheel forces after passage through the switch W, the force from the spring  100  causes plate member P to travel along its lower surface  98  over the roller members R and return to the rest position  98   a  on the surface  98 . In the absence of such wheel forces, spring  100  urges the switch point  48  into firm engagement with the side rail  34 . 
     The plate member P includes a generally circular upper plate or disk  112  ( FIGS. 15 ,  16  and  17 ) below which the skirt  102  and guide surface  98  are formed. The upper plate or disk  112  of plate member rests along a lower surface  114  on upper top wall  116  above a side wall  117  of the housing H. The plate member P has an internal sleeve  118  which is fitted over the shaft T to permit rotational movement of the shaft T with respect to the plate member P. 
     The shaft T is freely rotatable about its longitudinal axis with respect to the plate member P and a bearing  120  is located between the shaft and plate member to allow such rotational movement. The bearing  120  also reduces friction during manual operation of the switch stand S. The bearing  120  is fitted in a chamber or socket within a raised lip or rim  124  on an upper surface  126  of the plate member P. The plate member P also has a suitable number of spaced detents  128  formed on an outer rim or edge  130  of the upper plate disk  112 . The detents  128  are adapted to receive and engage a control lever L mounted with a top cap C ( FIGS. 3 ,  4  and  18 ). 
     The top cap C is fitted onto the shaft T and is lowered to a position adjacent a threaded outer surface  132  ( FIG. 11 ) formed on an upper portion  134  of the shaft T adjacent an upper end  136 . The top cap C has a threaded inner surface  137  formed in an upper sleeve  138 . The threaded inner surface  136  is mated to the threaded surface  134  of the shaft T. The cap C is assembled onto the shaft T by rotational engagement of the threaded surfaces  134  and  136  and thus is fixedly mountable with the shaft T for rotational movement therewith. The dimensions and extent of the threaded surfaces  134  and  136  are such that the spring  100  is compressed to the desired force level when the threaded connection is fully made. Lateral ports  142  are formed in the sleeve  138  of the cap C extending through the sleeve  138  for insertion of connector dowels or pins to lock the shaft T with the cap C after the threaded surfaces  134  and  136  are rotated into engagement with each other. 
     A control lever L is pivotally mounted at connector pins  144  in sockets  146  formed on an outer edge portion  150  of the cap C. The control lever L includes an inner end portion  152  inwardly from the pivotal connection with the cap C and a lower arm or grip portion  154  extending outwardly form such pivotal connection. The arm  154  of the control lever L is adapted to be fitted into firm fitting and locking engagement when in a lowered position as shown in the drawings ( FIG. 3 ) in a selected one of the detents  128  in order to interconnect the shaft T and the plate member P for concurrent movement. Thus there is no need for provision of a separate locking device or mechanism to lock the control lever L to the plate member P in the switch stand S. 
     The control lever L is also pivotally movable with respect to the cap C when in an unlocked position so that the inner end portion  152  is fitted within a set of upwardly extending lugs  162  formed on an upper surface  166  of the cap C. In this position, the force of the spring  100  does not act on the shaft T since the plate member P and the cap C are not interconnected. A crew member can then rotate the shaft T and cap C using the lever L and manually change the position of the switch points  46  and  48  through the linkage provided by the connecting rod  50 . Because the force of the spring  100  is not exerted on the shaft T at this time, relatively little force is needed. When the position of the switch points has been changed, the control lever L is then pivoted into the locking position as shown in  FIG. 3  and the switch W is locked in the new position. 
     The top cap member C has a socket or cup  170  ( FIG. 11 ) formed in the upper portion  136  with a threaded inner portion to receive a threaded lower end  174  ( FIGS. 3 and 4 ) of an indicator shaft or pole  176 . The indicator shaft  176  extends to an outer or upper end  178  which has a connector sleeve  180  mounted thereon. The connector sleeve  180  has connector ports or sockets  182  formed therein at suitable positions to receive connector pins or screws  184  and connect indicator panels or displays  186  and  188  which indicate the setting or position of the switch W. The indicator panels  186  and  188  have mating fitting notches  190  and  192  ( FIGS. 20 and 21 ) formed in them to allow the panels  186  and  188  to be interconnected at positions transverses to or intersecting each other. 
     As shown in the drawings, the panel  186  is of a generally rectangular shape, rounded at the corners and bearing thereon suitable indicator information, typically of a reflective material. The panel  188  is of the conventional arrow shape. The width of the fitting slots or notches  190  and  192  corresponds to the thickness of the panels  186  and  188 . Each of panels  186  and  188  has connector ports or holes for passage of connector screws or pins to attach such plate to the connector sleeve  180 . The sleeve  180  has a hole or socket at a lower end that connects with close tolerance with an upper end of the indicator shaft  176 . The connections between the sleeve  180  to the indicator shaft  176 , and of indicator shaft  176  to the shaft T, are secured by connector pins or other suitable fasteners or connectors. 
     In manual operation of the switch stand S of the present invention, the control lever L is unlocked and lifted out of the detent  128  in the plate member P in which it is currently located. A railroad service crew member can then using the lever L change the position of the shaft S and switch points  46  and  48 , as has been described. The cap member C with its connections at dowel pins in ports  142  is interconnected with the shaft T and movement from the lever L is transferred to the shaft T. The indicator panels  186  and  188  rotate with the shaft T and indicate the new setting or position of the switch W. 
     The plate member P with bearings  70 ,  72  and  120  allows such rotation to occur without requiring the resilient force exerted by spring  100  on the switch W by locked switch stand S to be overcome. The contact block B with its central passage  80  around the shaft T allows rotation of the shaft T to occur with respect to the housing H. 
     In a trailing operation, the switch W and switch stand S are in a locked or set position with the switch points  46  and  48  in the set or normal position allowing traffic onto the straight track ( FIG. 1 ) as is customary. When required to permit rolling stock to transfer from rails  42  and  44  through the switch W onto rails  32  and  34 , with the switch stand of the present invention, the switch stand S does not have to be manually unlocked to allow trailing operations to occur. The control lever L remains in the locked position in the plate member P and the shaft T and plate member P are interconnected for concurrent movement. 
     When wheels of rolling stock on the rails  42  and  44  contact the switch points  46  and  48 , the force exerted is sufficient to overcome the force of the spring  100  and allow the shaft T to rotate. The contact block B with its roller members R allows the camming surface  98  of the plate members P to move over the roller members R. Accordingly, the shaft T and switch points  46  and  48  move from the set position to allow passage of the rolling stock through the locked switch W. 
     The cap member C with its threaded engagement at surface  136  to the shaft T can be gradually unthreaded and released in order to slowly release the compressive force in the spring  100  when maintenance of the switch stand S is necessary. The connector pins in ports  142  are first removed. The cap member is then unthreaded from the shaft T. The dimensions of the threaded connection surfaces are such that when the unthreading is completed, the compressive forces of the spring  100  are also released. This is a simple mechanical operation, no great level of experience, training or skill is required. In addition no special tool to counter the force of the compressed spring  100  is required. 
     The switch stand S ( FIGS. 3 and 4 ) is what can be termed a high or tall switch stand. It should be understood that switch stands according to the present invention may take the form of a low switch stand such as that shown as the switch stand S- 1  ( FIG. 22 ). For any of several reasons, low switch stands may be required or used at locations where inadequate clearance or space is available for a high switch stand. 
     In the switch stand S- 1 , like structure to that of the switch stand S bears like reference numerals or indicator letters. The switch stand S- 1  includes a cap member C threaded onto a shaft T to cause a compressive force in a spring  100  in a like manner to the structure of  FIGS. 3 and 4 . The switch stand S- 1  also includes a control lever L pivotally mounted on the cap member as is shown in  FIG. 3 . The control lever L is locked into a detent in the plate member P, and the plate member has a camming surface  98  engaging guide rollers R on block member B. This structure permits trailing operations of the switch W in the switch stand S- 1  in a like manner to the switch stand S, as previously described. 
     In the switch stand S- 1 , the shaft T extends laterally or generally horizontally in a parallel plane to the surface on which the switch W and its associated track are positioned, rather than upwardly or vertically as is the case with the stand S. The shaft T in the switch stand S- 1  is connected by bevel gears  202  and  204  to a rotatable transfer shaft  206  connected at its lower end by a pivot eye to the connecting rod  50 . Thus the shaft T is operably interconnected to the switch W for corresponding movement in the manner described above for the switch stand S. The switch stand S- 1  allows manual operation of the switch W to change position in the manner previously described, while also allowing trailing operations while locked. 
     The indicator shaft  176  of the switch stand S- 1  is coaxially connected to the transfer shaft  206  to allow corresponding rotation of the shaft  176  and the shafts T and  206  to indicate the position or setting of the switch W. 
     Due to permitting trailing operations while the switch W is locked by engagement of the control lever in the plate member P, the modular switch stands S and S- 1  save being forced to make stops to unlock the switch stand for trailing operations. The effort for moving the switch points and temporarily allowing passage of rolling stock through the switch W is made by the effect of the rolling stock wheels and the train need not stop at the switch. Fuel consumption is reduced since a locomotive may continue at its desired and need not use additional fuel due to frequent stops and starts for switch manual switch adjustment for the purpose of allowing trailing operations. 
     With the capability of permitting trailing while the switch W is otherwise set for allowing through operation, the modular switch stands of the present invention do not need a padlock to keep the switch point in engagement with side rails. The control lever L is inserted and fitted into a slot or detent  128  of the plate member P for this purpose. The spring  100  in the housing H exerts the required pressure of the switch point  48  on the side rail  44 . 
     The switch stands according to the present invention with provision for trailing operations in the manner described are no larger than conventional types of manual switch stands. The location of the trailing mechanism inside the switch stand does not result in an increased profile height for the switch. It also does not hamper or interfere with other desired switch stand functions. 
     In addition to yard switching operations, a modular switch stand according to the present invention with its incorporated trailing mechanism can be used for main line and transit operations, such as in situations where trailing is not required or is not frequently used. The trailing mechanism according to the present invention is built into and integral with the switch stand and does not require that it be a separate unit from the switch stand at or near the throw bar. Further, maintenance and inspection is not difficult since the switch stand can be easily disassembled on site for access to inspect and service or replace the trailing mechanism within the switch stand. 
     Having described the invention above, various modifications of the techniques, procedures, material and equipment will be apparent to those in the art. It is intended that all such variations within the scope and spirit of the present invention as defined in the appended claims be embraced thereby.