Modular railroad switch stand

A switch stand for a railroad switch permits the switch to be locked against unauthorized movement of the switch. The switch stand permits trailing operation, even if locked. Passage of the rolling stock through the locked switch is permitted by allowing temporary movement of switch points of the switch when contacted by wheels of the rolling stock. The switch stand can also be unlocked and the position of the switch points changed manually to an alternate position from the normal or set position and then locked against unauthorized movement of the switch.

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.

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 inFIG. 1in what is known as a set position. In the set position, the switch W allows railroad rolling stock to move as indicated by an arrow30from rails32and34onto rails36and38of 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 arrow40, of rolling stock from rails32and34onto rails42and44of what is known as diverging track. In the alternate position, switch point46is in engagement with rail32and switch point48is spaced from the rail44to guide the rolling stock wheels from rails32and34onto rails42and44, 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 rails32and34when the switch W is in the set position shown inFIG. 1. In the trailing operation, switch points46and48of 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 inFIG. 1, while structural features are shown in other figures of the drawings. As shown inFIG. 1, the switch stand S is connected to the switch points46and48of the switch W by a linkage including a connecting rod50. The connecting rod50moves along its longitudinal axis as indicated at52to adjust the position of the switch points46and48. The connecting rod50is connected in the conventional manner to a conventional eye pin which is mounted on a socket60located at a lower end62of a shaft T. As the connecting rod50moves longitudinally and the position of the switch points46and48change, the shaft T rotates, as indicated schematically inFIG. 2, between positions54and56based on the limits of longitudinal movement of the connecting rod50. As mentioned above, the switch W permits trailing operations when wheels of rolling stock contact the switch points in transitioning from rails42and44(FIG. 1) to rails32and34. The shaft T is also rotatable through movement of the connecting rod50in response to movement of the switch points46and48of 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 socket60in the lower portion62for 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 rod50to the switch W. If desired, the sleeve60may 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 rod50, in order to have the correct throw in the switch points46and48.

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 passages62and64formed in interior body walls66and68of the housing H. The shaft T is freely rotatable about its longitudinal axis with respect to the housing H, and bearings70and72are mounted in ports62and64to 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 bearings70and72reduce 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 at34(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 bolts52(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 at54to 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 inFIGS. 3 and 4according 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. 5,12,13and14) of the switch stand S is mounted with the shaft T in an upper chamber76of the housing H above the wall68. The contact block member B has a central sleeve or opening80through which the shaft T passes. The sleeve80is 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 members82formed along an outer side wall84which are fitted into slots86(FIGS. 7,8and9) formed between guide channels87and88formed on each of opposed inner side walls90and92in the upper chamber76of 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 fingers82in the slots86against 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. 12,13and14) which are mounted for rotational movement on shafts96formed on the contact block member B. The shafts96are formed extending outwardly (FIG. 12) from outer side wall84at positions peripherally spaced from finger members82. The roller guide members R are urged upwardly by a resilient force-exerting member M (FIG. 3,4and5), typically a coiled spring100, into contact with a curved camming surface98formed on a lower circumferential portion or skirt102of a plate member P.

The spring100is positioned in the chamber76of the housing H between the wall68and a lower surface104within a pocket106formed 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 surface98. The size and contouring of the camming surface98aare 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 position98aslightly less than one-eighth turn or 45° to a location98bor98cas 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 points46and48during a trailing operation. On removal of such wheel forces after passage through the switch W, the force from the spring100causes plate member P to travel along its lower surface98over the roller members R and return to the rest position98aon the surface98. In the absence of such wheel forces, spring100urges the switch point48into firm engagement with the side rail34.

The plate member P includes a generally circular upper plate or disk112(FIGS. 15,16and17) below which the skirt102and guide surface98are formed. The upper plate or disk112of plate member rests along a lower surface114on upper top wall116above a side wall117of the housing H. The plate member P has an internal sleeve118which 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 bearing120is located between the shaft and plate member to allow such rotational movement. The bearing120also reduces friction during manual operation of the switch stand S. The bearing120is fitted in a chamber or socket within a raised lip or rim124on an upper surface126of the plate member P. The plate member P also has a suitable number of spaced detents128formed on an outer rim or edge130of the upper plate disk112. The detents128are adapted to receive and engage a control lever L mounted with a top cap C (FIGS. 3,4and18).

The top cap C is fitted onto the shaft T and is lowered to a position adjacent a threaded outer surface132(FIG. 11) formed on an upper portion134of the shaft T adjacent an upper end136. The top cap C has a threaded inner surface137formed in an upper sleeve138. The threaded inner surface136is mated to the threaded surface134of the shaft T. The cap C is assembled onto the shaft T by rotational engagement of the threaded surfaces134and136and thus is fixedly mountable with the shaft T for rotational movement therewith. The dimensions and extent of the threaded surfaces134and136are such that the spring100is compressed to the desired force level when the threaded connection is fully made. Lateral ports142are formed in the sleeve138of the cap C extending through the sleeve138for insertion of connector dowels or pins to lock the shaft T with the cap C after the threaded surfaces134and136are rotated into engagement with each other.

A control lever L is pivotally mounted at connector pins144in sockets146formed on an outer edge portion150of the cap C. The control lever L includes an inner end portion152inwardly from the pivotal connection with the cap C and a lower arm or grip portion154extending outwardly form such pivotal connection. The arm154of 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 detents128in 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 portion152is fitted within a set of upwardly extending lugs162formed on an upper surface166of the cap C. In this position, the force of the spring100does 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 points46and48through the linkage provided by the connecting rod50. Because the force of the spring100is 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 inFIG. 3and the switch W is locked in the new position.

The top cap member C has a socket or cup170(FIG. 11) formed in the upper portion136with a threaded inner portion to receive a threaded lower end174(FIGS. 3 and 4) of an indicator shaft or pole176. The indicator shaft176extends to an outer or upper end178which has a connector sleeve180mounted thereon. The connector sleeve180has connector ports or sockets182formed therein at suitable positions to receive connector pins or screws184and connect indicator panels or displays186and188which indicate the setting or position of the switch W. The indicator panels186and188have mating fitting notches190and192(FIGS. 20 and 21) formed in them to allow the panels186and188to be interconnected at positions transverses to or intersecting each other.

As shown in the drawings, the panel186is of a generally rectangular shape, rounded at the corners and bearing thereon suitable indicator information, typically of a reflective material. The panel188is of the conventional arrow shape. The width of the fitting slots or notches190and192corresponds to the thickness of the panels186and188. Each of panels186and188has connector ports or holes for passage of connector screws or pins to attach such plate to the connector sleeve180. The sleeve180has a hole or socket at a lower end that connects with close tolerance with an upper end of the indicator shaft176. The connections between the sleeve180to the indicator shaft176, and of indicator shaft176to 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 detent128in 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 points46and48, as has been described. The cap member C with its connections at dowel pins in ports142is interconnected with the shaft T and movement from the lever L is transferred to the shaft T. The indicator panels186and188rotate with the shaft T and indicate the new setting or position of the switch W.

The plate member P with bearings70,72and120allows such rotation to occur without requiring the resilient force exerted by spring100on the switch W by locked switch stand S to be overcome. The contact block B with its central passage80around 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 points46and48in 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 rails42and44through the switch W onto rails32and34, 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 rails42and44contact the switch points46and48, the force exerted is sufficient to overcome the force of the spring100and allow the shaft T to rotate. The contact block B with its roller members R allows the camming surface98of the plate members P to move over the roller members R. Accordingly, the shaft T and switch points46and48move 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 surface136to the shaft T can be gradually unthreaded and released in order to slowly release the compressive force in the spring100when maintenance of the switch stand S is necessary. The connector pins in ports142are 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 spring100are 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 spring100is 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-1includes a cap member C threaded onto a shaft T to cause a compressive force in a spring100in a like manner to the structure ofFIGS. 3 and 4. The switch stand S-1also includes a control lever L pivotally mounted on the cap member as is shown inFIG. 3. The control lever L is locked into a detent in the plate member P, and the plate member has a camming surface98engaging guide rollers R on block member B. This structure permits trailing operations of the switch W in the switch stand S-1in 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-1is connected by bevel gears202and204to a rotatable transfer shaft206connected at its lower end by a pivot eye to the connecting rod50. 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-1allows manual operation of the switch W to change position in the manner previously described, while also allowing trailing operations while locked.

The indicator shaft176of the switch stand S-1is coaxially connected to the transfer shaft206to allow corresponding rotation of the shaft176and the shafts T and206to 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-1save 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 detent128of the plate member P for this purpose. The spring100in the housing H exerts the required pressure of the switch point48on the side rail44.

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.