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.
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.
In the drawings, the letter S designates generally a switch stand according to the present invention. The switch W is shown in
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
The switch stand S of the present invention is shown schematically in
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 (
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 (
The modular switch stand S shown in
A contact block member B (
The switch stand S of the present invention includes one or more roller guide members R (
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 98a 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 98a slightly less than one-eighth turn or 45° to a location 98b or 98c 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 98a 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 (
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 (
The top cap C is fitted onto the shaft T and is lowered to a position adjacent a threaded outer surface 132 (
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 (
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
The top cap member C has a socket or cup 170 (
00501 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 (
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 (
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
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.