Embodiments of the invention relate generally to switching devices. Other embodiments relate to a method and apparatus for maintaining the functionality of a railway switching device.
As is commonly known, railway switch point assemblies include two rail end points which are tapered rail profiles capable of deflecting to move between two different positions in order to facilitate the correct alignment of the track components for the desired path of rolling stock transiting through the switch point assembly. The switch point assembly has two deflectable or movable rail end points which move in concert with one another between first and second alternative positions. In a first alternative position, a first one of these movable rail end points can be aligned with a first fixed stock rail to facilitate passage of the rolling stock straight through the switch point onto a first set of fixed rails. In a second alternative position, the second movable rail end point can be aligned with a second fixed stock rail to facilitate passage of the rolling stock onto a second set of fixed rails, such as to divert the rolling stock onto a siding.
In a typical switch point assembly, the two deflectable rail end points are moved by rods protruding from the opposite extremities of a unit often called a switch point machine. Inside the switch point machine, the rods are usually connected to a device with a reciprocating straight line motion, which is powered by a motor unit which is generally placed to the side of the rails. The state of the art includes numerous switch point machines for railway split point movements. Such mechanisms are normally installed at the switch point, and they are typically applied only to move the split rail end points of the switch point assembly.
Unless the switch is locked, a train coming from either of the converging directions may pass through the points, regardless of the position of the points, as the vehicle's wheels will force the points to move. Passage through a switch in this direction is known as a trailing-point movement.
In a trailing-point movement, the wheels will force the points to the proper position. This is sometimes known as running through the switch. If the points are rigidly connected to the switch control mechanism (e.g., a non-trailable switch machine), which is often desirable to ensure reliable operation, the switch mechanism's linkages may be bent, requiring repair before the switch is again usable. Certain switch machines may betrailable but are only acceptable for limited trailing forces and are only approved for limited speed, in stations or maneuver zones.
It may be desirable, therefor, to have a system and method that maintains the functionality of the switch point machine after trailing-point movements, without damage to the switch point assembly, switch point machine, fixed rails, etc.
An embodiment of the invention relates to an apparatus. The apparatus includes a clamp block configured for attachment to a rail end point, the clamp block including a housing having a slot formed therein, and a clip configured to be received in the slot. The clip is disengageable from the slot upon application of a generally lateral trailing force to the rail end point in excess of a threshold value.
Another embodiment of the invention relates to an assembly. The assembly includes a first rail end point, a second rail end point, a switch machine configured to selectively move the first rail end point and second rail end point between first and second alternative positions, and a first clip assembly connecting a first end of the switch machine to the first rail end point. The first clip assembly is configured to transmit a pushing force from the switch machine to the first rail end point to move the first and second rail end points between the first and second alternative positions, and to automatically decouple the switch machine from the first rail end point during a trailing-point movement of a vehicle.
Yet another embodiment of the invention relates to a method. The method includes the steps of connecting a first rail end point to a switch machine via a first clip assembly, the first clip assembly being configured to transmit a pushing force from the switch machine to the first rail end point to selectively move the first rail end point between first and second alternative positions, and during a trailing-point movement of a vehicle, automatically decoupling the switch machine from the first rail end point.
The present invention will be better understood from reading the following description of non-limiting embodiments, with reference to the attached drawings, wherein below:
Reference will be made below in detail to exemplary embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numerals used throughout the drawings refer to the same or like parts. Although exemplary embodiments of the invention are described with respect torailway switch point machines, embodiments of the invention may also be applicable for use with switching devices, generally, including any device where both rigid and decoupling modes may be beneficial.
As used herein, “selectively coupled” means that a component may be coupled to another component in one mode of operation, and decoupled with the another component in another mode of operation.
With reference to
The two deflectable rail end points 12, 14 are moved by rods 24, 26 protruding from the opposite extremities of a unit called a switch point machine 28 (also referred to herein as a switch machine). Inside the switch point machine 28, the rods 26, 28 are usually connected to a device with a reciprocating straight line motion, which is powered by a motor unit which is generally placed to the side of the rails. In some configurations, a connecting rod or tie bar 30 may be utilized to tie the rail end points 12, 14 rigidly to one another. As shown in
As illustrated in
With further reference to
Referring once again to
Turning now to
As illustrated in
During normal operation, for facing-point movements, the switch machine 28 is selectively operable to control the rail end points 12, 14 between the first and second alternative positions to direct the rolling stock either straight through the switch point onto the first set of fixed rails 18 or to divert the rolling stock onto a second set of fixed rails 22. In particular, the rods 26, 28 of the switch machine 26, 28 are selectively extendable to move the rail end points 12, 14 between the first and second positions. As one of the rods 26, 28 is extended, the outward pushing force from the rod is transmitted to the adjacent rail end point 12, 14 through the clip assembly 36. Indeed, during facing-point movements, the clip 42 is configured to maintain a reliable and rigid connection to allow for movement of the rail end points 12, 14 to the desired orientation. More specifically, the disc springs 70 of the clip retaining mechanism 74 provide a large pre-setting compression force to provide the required rigidity of the entire switch point assembly 10 necessary to move and lock the rail end points 12, 14. In this respect, the assembly 10 of embodiments of the invention offers the same functionality during facing-point movements as existing assemblies. In particular, during normal operation, the assembly 36 is configured to lock the rail end points 12, 14 into location with high forces to minimize derailments.
With reference to
Turning now to
As the rail end point 12 is pushed outward by the trailing force, however, the clip 42 begins to rotate about the pivot pin 40, as shown in the upper portion of
As will be readily appreciated, the trailable clip assembly 36 is compact in design and is able to maintain a reliable and rigid connection between the switch machine and point rails under normal operation, while also being able to disconnect the switch machine from the point rail in trailing operation. In particular, the forces typically encountered during normal operation are not sufficient to cause the clip 42 to decouple from the clamp block 44, as such forces are much less than those seen during trailing operation. The trailable clip 42 is, however, configured to reliably decouple when subjected to the much larger forces during trailing operation. The force at which the clip 42 disengages from the housing 64 rather than move in concert with the clamp block 44 is referred to herein as the threshold force. In an embodiment, the threshold force value is at least 20,000 pounds (at least 88,000 newtons). This is in contrast to existing systems which utilize a clip that is incapable of disengaging from the point rail/rail end point without damage. As a result, in one aspect, the assembly maintains the integrity and functionality of the rail end points, the switch machine, and the rolling stock even after trailing-point movements
Moreover, the simplicity of the design of the trailable clip assembly 36 allows for quick and easy replacement in the field. In addition, the reduction in parts as compared to existing assemblies translates to a reduction in costs and an ease of replacement and servicing.
An embodiment of the invention relates to an apparatus. The apparatus includes a clamp block configured for attachment to a rail end point, the clamp block including a housing having a slot formed therein, and a clip configured to be received in the slot. The clip is disengageable from the slot upon application of a generally lateral trailing force to the rail end point in excess of a threshold value. In an embodiment, the clip is generally U-shaped and includes a pair of opposed depending legs each having an aperture formed therein adjacent to respective distal ends thereof for receiving a pivot pin, and an upwardly extending third leg. The third leg is configured to be received in the slot in the housing of the clamp block. In an embodiment, the apparatus includes a clip retaining mechanism configured to retain the clip within the slot. The clip retaining mechanism may include at least one detent ball and a biasing mechanism configured to bias the at least one detent ball into engagement with a corresponding detent recess in the clip. In an embodiment, the biasing mechanism is at least one disc spring. In an embodiment, the clip retaining mechanism is positioned within the housing of the clamp block. In an embodiment, the apparatus may include a second clip retaining mechanism configured to retain the clip within the slot. The second clip retaining mechanism is positioned within the housing on an opposing side of the clip from the clip retaining mechanism and includes at least one second detent ball and a second biasing mechanism configured to bias the at least one second detent ball into engagement with a corresponding second detent recess in the clip. In an embodiment, the apparatus includes a connecting block engageable with the clamp block. The connecting block is configured to facilitate the attachment of a connecting rod between the clamp block and an opposing clamp block. In an embodiment, the apparatus is configured to couple the rail end point to a switch machine. In an embodiment, the clip is configured to maintain a rigid connection with the clamp block sufficient to transfer a pushing force from the switch machine to the rail end point, wherein the pushing force of the switch machine is below the threshold value.
Another embodiment of the invention relates to an assembly. The assembly includes a first rail end point, a second rail end point, a switch machine configured to selectively move the first rail end point and second rail end point between first and second alternative positions, and a first clip assembly connecting a first end of the switch point machine to the first rail end point. The first clip assembly is configured to transmit a first pushing force from the switch machine to the first rail end point to move the first and second rail end points between the first and second alternative positions, and to automatically decouple the switch machine from the first rail end point during a trailing-point movement of a rolling vehicle. In an embodiment, the assembly also includes a second clip assembly connecting a second end of the switch point machine to the second rail end point. The second clip assembly is configured to transmit a second pushing force from the switch machine to the second rail end point to move the first and second rail end points between the first and second alternative positions, and to automatically decouple the switch machine from the second rail end point during the trailing-point movement of the rolling vehicle. In an embodiment, the first clip assembly and second clip assembly each include a clamp block configured for attachment to a respective one of the first and second rail end points, each clamp block including a housing having a slot formed therein, and a clip configured to be received in the slot. The clip is disengageable from the slot upon application of a generally lateral trailing force to one of the first and second rail end points during the trailing-point movement. In an embodiment, each clip is generally U-shaped and includes a pair of opposed depending legs each having an aperture formed therein adjacent to respective distal ends thereof for receiving a pivot pin, and an upwardly extending third leg, wherein the third leg is configured to be received in the slot in the housing of the clamp block. The first and second clip assemblies may each include a clip retaining mechanism configured to retain the clip within the slot, the clip retaining mechanism including at least one detent ball and a biasing mechanism configured to bias the at least one detent ball into engagement with a corresponding detent recess in the clip. In an embodiment, the biasing mechanism is at least one disc spring. In an embodiment, the first and second clip assemblies each include a connecting block engageable with each clamp block, the connecting blocks being configured to facilitate the attachment of a connecting rod between the first clip assembly and the second clip assembly. In an embodiment, each clip is configured to maintain a rigid connection with the respective clamp block sufficient to transfer the pushing force from the switch machine to the first or second rail end point.
Yet another embodiment of the invention relates to a method. The method includes the steps of connecting a first rail end point to a switch machine via a first clip assembly, the first clip assembly being configured to transmit a pushing force from the switch machine to the first rail end point to selectively move the first rail end point between first and second alternative positions, and during a trailing-point movement of a vehicle, automatically decoupling the switch machine from the first rail end point. In an embodiment, the method may also include the steps of connecting a second rail end point to the switch machine via a second clip assembly, the second clip assembly being configured to transmit a second pushing force from the switch machine to the second rail end point to selectively move the second rail end point, and during the trailing-point movement of a vehicle, automatically decoupling the switch machine from the second rail end point. In an embodiment, the first clip assembly and second clip assembly each include a clamp block configured for attachment to a respective one of the first and second rail end points, each clamp block including a housing having a slot formed therein, and a clip configured to be received in the slot. The clip is disengageable from the slot upon application of a generally lateral trailing force to one of the first and second rail end points during the trailing-point movement. In an embodiment, each clip is generally U-shaped and includes a pair of opposed depending legs each having an aperture formed therein adjacent to respective distal ends thereof for receiving a pivot pin, and an upwardly extending third leg. The third leg is configured to be received in the slot in the housing of the clamp block. In an embodiment, the first and second clip assemblies each include a clip retaining mechanism configured to retain the clip within the slot, the clip retaining mechanism including at least one detent ball and a biasing mechanism configured to bias the at least one detent ball into engagement with a corresponding detent recess in the clip.
It is to be understood that the above description is intended to be illustrative, and not restrictive. For example, the above-described embodiments (and/or aspects thereof) may be used in combination with each other. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from its scope. While the dimensions and types of materials described herein are intended to define the parameters of the invention, they are by no means limiting and are exemplary embodiments. Many other embodiments will be apparent to those of skill in the art upon reviewing the above description. The terms “including” and “in which” are used as the plain-English equivalents of the respective terms “comprising” and “wherein.” Moreover, the terms “first,” “second,” “third,” “upper,” “lower,” “bottom,” “top,” etc. are used merely as labels, and are not intended to impose numerical or positional requirements on their objects.
This written description uses examples to disclose several embodiments of the invention, including the best mode, and also to enable one of ordinary skill in the art to practice the embodiments of invention, including making and using any devices or systems and performing any incorporated methods.
As used herein, an element or step recited in the singular and proceeded with the word “a” or “an” should be understood as not excluding plural of the elements or steps, unless such exclusion is explicitly stated. Furthermore, references to “one embodiment” of the present invention are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. Moreover, unless explicitly stated to the contrary, embodiments “comprising,” “including,” or “having” an element or a plurality of elements having a particular property may include additional such elements not having that property.
Since certain changes may be made in the embodiments described herein, it is intended that all of the subject matter of the above description or shown in the accompanying drawings shall be interpreted merely as examples illustrating the inventive concept herein and shall not be construed as limiting the invention.
Filing Document | Filing Date | Country | Kind |
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PCT/CN2015/076757 | 4/16/2015 | WO | 00 |
Publishing Document | Publishing Date | Country | Kind |
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WO2016/165109 | 10/20/2016 | WO | A |
Number | Name | Date | Kind |
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5730395 | Carmes | Mar 1998 | A |
Number | Date | Country |
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2494378 | Jun 2002 | CN |
101870300 | Oct 2010 | CN |
0802102 | Oct 1997 | EP |
233285 | May 1925 | GB |
Entry |
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International Search Report for PCT/CN2015/076757, dated Jan. 21, 2016. |
Written Opinion of the International Searching Authority for PCT/CN2015/076757, completed Jan. 15, 2016. |
Number | Date | Country | |
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20180087223 A1 | Mar 2018 | US |