Switch Point Roller Assembly

This application claims the benefit of priority to: U.S. Provisional No. 63/632,267 entitled “SWITCH POINT ROLLER ASSEMBLY,” filed on Apr. 10, 2024, and U.S. application Ser. No. 19/067,717 entitled “SWITCH POINT ROLLER ASSEMBLY,” filed on Feb. 28, 2025.

All the aforementioned applications are hereby incorporated by reference in their entirety.

Railway switch points have various moving parts that are subject to maintenance operations in order to reduce mechanical failure. Typically, a switch point is moved with the assistance of a switch machine. As the force of the switch machine causes the switch point to move, the base of the switch point is in contact with the dorsal surfaces of railway plates. Even if the switch point is floating above such surfaces, the forces of passing railway stock cause the switch point to contact these surfaces. In the best case, the switch point is only forced in a vertical motion. However, often, the switch point is subject to both longitudinal forces while also being subject to vertical force (from rolling stock).

In the current state of the art, railway maintenance personnel administer lubricants at or near the switch point in order to reduce friction. However, such operations are labor-intensive and, thus, costly. Further, as with any human-based operation, the maintenance operations may be subject to human error. The human error can lead to the premature degradation of switch points which, at a minimum, increases long-term maintenance and/or replacement costs. In some cases, the switch point may completely seize due to lack of lubrication and become inoperative. In sum, the failure of switch points can lead to damage to property, potentially with the loss of human life.

Even when properly administered, lubricants only have a fixed duty cycle. The lubricants may degrade due to chemical composition, environmental factors, impurities, excessive friction, tamping, etc. Further, the amount of lubricant applied may be excessive or insufficient—both of which may, again, lead to loss of property and even life. Lubricant, even when properly administered, is difficult to verify for efficacy, i.e., human operators cannot quickly or even easily determine whether the lubricant is indeed performing as desired. In short, lubricants are not a wholly viable solution to reducing friction at or near switch points.

What is needed is a switch point roller assembly that provides reduced maintenance, improved safety, and many other benefits.

A solution is disclosed which includes a switch point roller assembly and a kit. The kit may comprise a switch point and a switch point roller assembly, in one configuration. The switch point roller assembly may be configured for operation at or near a switch point of a railway switch.

The switch point roller assembly comprises a spring, a bolt assembly comprising a bolt and a nut, wherein the bolt comprises a hex head, wherein the hex head provides adjustment of the bolt. The switch point roller assembly further comprises a roller assembly comprising a roller, an axle retainer, and a first axle, wherein the axle retainer is operatively connected to the bolt assembly, wherein the first axle is disposed within the roller and the axle retainer, wherein the roller assembly is adjustable by the bolt assembly via the hex head.

The switch point roller assembly further comprises a housing assembly comprising a housing, wherein the housing assembly is operatively connected to the roller assembly via the bolt assembly, wherein the housing assembly is further operatively connected to the roller assembly, wherein the housing comprises (1) a first plurality of surfaces and (2) a second plurality of surfaces, wherein the nut is configured to substantially secure the bolt to a first surface within the first plurality of surfaces, wherein the spring is configured to be disposed between the base plate and a second surface within the second plurality of surfaces, wherein the housing further comprises a third plurality of surfaces, wherein the roller assembly is disposed partially within the housing with respect to the third plurality of surfaces.

The switch point roller assembly further comprises a base plate comprising a plurality of slots configured to attach the base plate to the switch point, wherein the base plate further comprises a spring support, wherein the spring is supported by the spring support and is in contact with the housing assembly.

The bolt comprises (1) a first bolt segment of a first diameter and is threaded, (2) a second bolt segment being a second diameter, wherein the second diameter is smaller than the first diameter, and (3) a third bolt segment, wherein the third bolt segment has a third diameter, wherein the third diameter is smaller than the second diameter.

The roller assembly further comprises (1) a first bushing in contact with the bolt assembly, (2) a retaining ring, wherein the retaining ring retains the bolt assembly at the axle retainer, and (3) a plurality of needle bearings, wherein the plurality of needle bearings provides for rolling of the roller about the first axle.

The axle retainer comprises (1) a first plurality of holes, supporting the first axle, and (2) a first hole accommodating the first bushing. The housing assembly comprises (1) a plurality of bushings, (2) a second axle, wherein the second axle is disposed within the plurality of bushings, (3) a plurality of retaining rings, wherein the plurality of retaining rings is configured to retain the second axle, and (4) a set screw, wherein the set screw is configured to be in contact with the second axle.

The housing further comprises (1) a second plurality of holes configured to accommodate the plurality of bushings and (2) a second hole configured to accommodate the bolt assembly. The base plate further comprises a protrusion having a third hole configured to accommodate the housing assembly, wherein the protrusion further comprises a threaded hole, wherein the threaded hole is oriented perpendicularly to the third hole and is configured to receive a set screw.

The spring support comprises an inner spring support and an outer spring support, wherein the spring is supported, at an inner diameter of the spring, via the inner spring support, wherein the spring is further supported, at an outer diameter of the spring, via the outer spring support. The spring may be polymer, polyester, urethane, hardened steel, or a combination thereof. The roller may be polymer, polyester, urethane, hardened steel, scaled glass having a nylon interior, or a combination thereof.

Various aspects will be described in detail with reference to the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. References made to particular examples and implementations are for illustrative purposes, and are not intended to limit the scope of the claims.

Railway maintenance is critical to the safety of personnel, passengers, and property. Typically, lubricants are used to maintain moving parts within trackwork. However, some mechanical solutions are deployed as needed in order to reduce maintenance and improve safety. That stated, existing solutions have many problems that are addressed by the solution disclosed herein.

Some existing switch point roller solutions rely on installation below the switch point. For example, the switch point roller may be attached to the tie (i.e., sleeper) and/or railway plate with upward facing rollers that are in contact with the ventral surface of the moving switch point. These types of existing approaches may be thought of as “top up” solutions. One disadvantage of such solutions is the installation often requires the removal of existing hardware and components in order to access the installation point. For example, an entire railway tie may need removal and replacement in order to install the rolling assemblies. Alternatively, the switch point may require significant adjustment to access the area where such a rolling assembly would require installation.

In contrast, the disclosed solution is configured to be a “top-down” approach to the problem. The solution is configured to being attached to the switch point itself at the web (or D-bar) such that the switch point may be left in place during installation. Further, the railway tie and/or railway plate may be left in position during installation. As such, the disclosed solution may be easily installed and inspected by avoiding mechanical changes to additional track components.

Another problem with existing top-up solutions is the inability to easily inspect the installation and operation of the rolling assembly. Again, these types of solutions are installed below the moving switch point, sometimes within the railway tie or railway plate itself. When the device is in operation, personnel cannot see the actual operation of the device but only the switch point and surrounding components. As such, the device may be failing without personnel even noticing. This situation is often worse than application of lubricants because the device may entirely seize up and lead to failure of the entire switch.

In contrast, the disclosed solution is configured to be installed above the railway plate. As such, the disclosed solution is readily inspectable by personnel and/or more advanced techniques (e.g., automated inspection systems). Again, the disclosed solution is configured to being attached at or near the web of the switch point, thus being readily available for inspection.

Existing top-up solutions are difficult to maintain. Even assuming that inspection is easily performed, existing devices still require non-trivial maintenance and replacement operations. This situation is often as difficult if not more difficult than the already difficult installation process. One could foresee situations where the inspection only reveals a failing rolling device, e.g., by seizure of the switch point. However, the exact failing components may be unknown since the device cannot be visually inspected without removable and significant adjustment of the switch point.

In contrast, the disclosed solution is configured to being installed at or near the switch point. As such, the disclosed solution may be readily inspected and readily maintained. As with any railway component, the disclosed solution will be subject to severe wear-and-tear—including both environment and operational. Components may fail within the disclosed solution. For example, the roller may degrade due to environmental conditions. When this degradation is detected by personnel, the roller may be readily removed and replaced. Further, this operation is relatively fast when compared to existing solutions that are installed below the switch point.

Some existing solutions are attached via clamps at the base of the switch point. Clamps tend to fail because the clamping force is created by reciprocal clamps (or arms) that are both secured by bolts. One cause of failure is losing tension within the clamp (e.g., from failure of one or more of the bolt assemblies). Another cause of failure is simply the operation of rolling stock at the clamp which essentially vibrates the clamp from the rail. Personnel must then inspect and adjust the clamps to ensure the attached roller assemblies are still positioned and secured to support the transitions of the switch point.

In contrast, the disclosed solution is configured to being attached at or near the web of the switch point. The base plate of the disclosed solution may be bolted to the web at a D-bar assembly that is, in turn, connected to the switch point. As such, the disclosed solution relies on one or more bolts that are (1) easily accessible for installation and (2) readily torqued to maintain position.

Clamp-based solutions introduce interference issues at the railway. For example, the clamp often spans below the rail (or switch point) which requires the movement area to be free of objects. Otherwise, the clamps may interfere with gauge-side and/or field-side components. Even with the best clearance, conditions within the track change. For example, ballast may move out of position and start interfering with the clamps, thus leading to interference with the existing top-up solution. Another factor is tamping operations that may simply strike the clamps and disconnect the clamp-based solution from the track.

In contrast, the disclosed solution is configured to being secured at the web of the switch point. This configuration does not introduce the unnecessary risk of interference with gauge-side or track-side components. For example, the movement of ballast does not introduce a high-level of risk when compared to clamp-based solutions that are installed at the base of the rail and/or switch point.

Some top-down solutions rely on mechanical arms that protrude from the web of the rail. These arms hold the roller which then traverses the railway plate during movement of the switch point. However, these arm-based solutions require tensioning to adequately adjust the arm in order to create enough force to support the switch point during movement. Improper tension may cause the roller to be ineffective. Alternatively, improper tension may cause the entire device to break when loaded.

In contrast, the disclosed solution relies on a roller assembly that is substantially oriented toward the railway plate. This configuration is based, in part, on a housing assembly that supports the roller assembly via an axle. Minimal, if any, adjustment is necessary to enable the proper contact between the roller and the railway plate (or tie).

Existing solutions often fail to protect sensitive hardware from conditions at the track. For example, some solutions have adjustment/tensioning hardware that is unprotected from environmental elements. Other risks include maintenance equipment striking this type of hardware (e.g., during tamping operations). Any damage to adjustment hardware is undesirable. At a minimum, damage will cause the adjustments to deviate from nominal. At worst, the hardware component may be destroyed, thus leading to failure of the device. In short, existing solutions fail to consider the extreme conditions that trackside components face when operating in the field.

In contrast, the disclosed solution is configured such that sensitive hardware is provided additional protection from such hazards, damage, etc. For example, the switch point rolling assembly is configured such that a bolt assembly is partially protected, via a housing assembly, from hazards. This protection ensures the adjustments are maintained over the course of deployment but also that the bolt assembly has a longer duty cycle. The housing assembly is configured to provide protection while not impeding inspection, adjustment and service of components. Similar protection is provided to the spring and the roller assembly, as shall be disclosed below. In short, the disclosed solution provides enhanced protection of components without sacrificing serviceability.

Some existing solutions require careful adjustments to be made in order to provide consistent contact between the roller and the track component (e.g., the railway plate). However, any adjustment will be imperfect. For example, a railway plate itself may be uneven. As such, a static adjustment may not be sufficient to maintain contact between the roller and the railway plate.

In contrast, the disclosed solution is configured to maintain consistent contact between the roller assembly and the railway plate. The switch point roller assembly comprises a housing assembly that is substantially in contact with a spring that is, in turn, in contact with a base plate. The interaction of these components is such that the roller assembly maintains substantially consistent contact with the railway plate. Even with uneven surfaces at the railway plate, the roller assembly is configured to adjust dynamically.

Further benefits over the existing solutions shall be disclosed below through various embodiments/aspects of the disclosed solutions. One of skill in the art will appreciate that disclosed solution addresses many problems in the industry. As such, the maintenance of railway systems is improved which, in turn, leads to improved safety for personnel, passengers, and property.

is a planar view of a switch point roller assembly, as shown from a front perspective. A plurality of axes is shown viz. a first axisX (projected toward the viewer), a second axisY, and a third axisZ. The axisX is perpendicular to the direction of rolling stock traveling along the track. The axisY is parallel to the direction of travel of rolling stock moving along the track. The axisZ is vertical, as formed by the normal vector of the axesX,Y.

The switch point roller assemblycomprises a base platewhich comprises a plurality of slotsZ. The plurality of slotsZ comprises a first slotA and a second slotB. The plurality of slotsZ is configured to enable the switch point roller assemblyto be operatively connected to a switch point.

In one aspect, the switch point may be of a shape that is not completely formed of right angles. In other words, the web of the rail may be of a curved shape. In the industry, the rail may be referred to as a Vignoles rail, a T-rail, an asymmetric rail, etc. As such, the rail may have a D-bar which provides an interface to the rail (or switch point) such that the substantially flat surface of the base platemay be operatively connected to the rail (via the D-bar interface). In another aspect, the rail (or switch point) may already be substantially flat and not require a D-bar interface—in which case the base platemay be directly attached to the rail (or switch point) via hardware passing through the plurality of slotsZ.

As shown, the base plateis substantially flat at the distal and proximal surfaces (as viewed from the axisX). However, the base plate, in one configuration, may be designed such that the surface of the base plateinterfaces directly with any shape of web. Stated differently, the base platemay be a combination of the D-bar and the base plate, as instantly shown.

As shown, the base plateis depicted without associated hardware to operatively connect the base platewith the switch point. One of skill in the art will appreciate that various bolts, nuts, locking washers, washers, screws, etc. may be utilized to attach the switch point roller assemblyto the switch point. In one aspect, the base platemay be permanently attached to the switch point (e.g., via welding).

The switch point roller assemblyfurther comprises a housingwhich is generally configured to house a roller. The rollermay be made from polymer, polyester, urethane, hardened steel, sealed glass (with a nylon interior), etc. The material chosen may further depend on the operating environment as well as the implementation considerations (e.g., cost). The rollerprovides for the movement of the switch point across the railway plate during transitions of the switch point caused by a switch machine. Therefore, when the switch point is under load from railway stock, the rollerprovides for rotational movement of the switch point roller assembly.

The housingsubstantially houses an axle retainerthat is operatively connected to an axle(which is not visible in the instant view). The axleis operatively connected to the rollersuch that, again, the rollermay roll across the railway plate when the switch point is either moving or under load from rolling stock. One advantage of the configuration of the axle retainerand the housingis to substantially protect the moving parts associated with the roller(e.g., needle bearings, bushings, retaining rings, etc.). Further, the housingenables retention of the axle, as will be shown in subsequent views.

The housingis operatively connected to an axlewhich protrudes from the housing. The axleis retained by a plurality of retaining ringsZ (which comprises a first retaining ringA and a second retaining ringB). Retaining rings may be referred to as “lock rings” or “locking rings” in the industry. The plurality of retaining ringsZ is generally configured to retain the axlewhich protrudes from the housingat a protrusion(not shown in the instant view). The instant view does not show an internal protrusion of the base platethat provides a pivot about which the housingmay move. That stated, the axlepasses through the protrusionand operatively connects the housingto the base plate(via the axle).

The housingis configured to rotate about the axlesuch that the rollermaintains contact with the railway plate, upon which the switch point frequently rests (via the switch point roller assemblyas a whole). This contact is maintained, in part, by force created by a spring(not shown) that affects the rotation about the axle.

The rolleris adjusted via a bolt. The boltcomprises an internal hex headA, a first segmentB, a second segmentC (not shown), and a third segmentD (not shown). The internal hex headA enables the adjustment of the boltthat is operatively connected to the axle retainer. The boltis generally configured to enable adjustment of the axle retainer(and associated roller) in order provide effective rolling of the switch point roller assemblyat the railway plate.

The housingcomprises a first plurality of surfacesZ. The first plurality of surfacesZ comprises a first surfaceA, a second surfaceB, a third surfaceC, and a fourth surfaceD. The plurality of surfacesZ provides a partial enclosure of the boltand the nut(both of which may be considered a bolt assembly), specifically the surfacesB,C,D.

As stated, railway operating environments have many hazards, both mechanical and environmental. Objects may strike track elements and cause damage. The surfacesB,C are configured to deflect objects away that may strike the bolt assemblyfrom the direction of travel of rolling stock (along the axisY). For example, a dragging chain would be deflected away from the hex headA of the boltby the surfaceC. One particular advantage of the partial enclosure is that the bolt assemblyis still serviceable by tools. Further, the bolt assemblyis still subject to visual inspection without removal of a hood or cap at the housing.

Railway tracks are routinely serviced via two processes that are particularly hazardous to equipment and components at or near the rails. The first is tamping which is the process of adjusting the ballast at or near the track. In many railways, the ballast comprises heavy rock that is moved into position and tamped for stability. As such, the rocks (and other substrate) are distributed to undesirable places in the track (e.g., a rock falling between a switch point). To clean up the ballast, a brushing process is utilized to mechanically brush excess ballast out of the track. In short, the tamping and brushing process are harsh on railway components.

Therefore, the surfacesB,C,D are configured to protect the bolt assemblyfrom these tamping and brushing processes. One of skill in the art will appreciate that the bolt assemblymay have sensitive adjustments that a tamping machine and/or a brushing machine may inadvertently damage—or simply cause the bolt assemblyto become unaligned.

The housingcomprises a plurality of surfacesZ at the ventral surface of the housing. The plurality of surfacesZ comprises a first surfaceA and a second surfaceB (not shown in the instant view). The plurality of surfacesZ is disposed lower to partially protect the roller. As stated, railway operating environments are hazardous. The plurality of surfacesZ is configured to partially protect the rollerfrom damage. Further, the plurality of surfacesZ is configured to protect the axleand the axle retainer. Additionally, the plurality of surfacesZ is configured to retain the axlewithout additional hardware, if so configured.

The boltmay be locked via a nutat the surfaceA of the housing. Additional hardware may be used to fix the boltin position (e.g., locking washers, washers, retaining rings, etc.).