WO2023202003A1

WO2023202003A1 - Rail grinding apparatus

Info

Publication number: WO2023202003A1
Application number: PCT/CN2022/124612
Authority: WO
Inventors: Wai Lun Ho
Original assignee: Jabez Innovation Ltd
Current assignee: Jabez Innovation Ltd
Priority date: 2022-04-21
Filing date: 2022-10-11
Publication date: 2023-10-26
Anticipated expiration: 2024-10-21

Abstract

A rail grinding apparatus which includes a first grinding head adapted to at least partially contact a running surface of the rail, and a magnetic component for connecting the rail grinding apparatus to the rail via a magnetic attracting force. The first grinding head is rotatable in order to grind the running surface. A magnetic attraction force generated by the magnetic component presses the first grinding head to onto the running surface of the rail. The lightweight rail grinder is particularly suitable for using on steep rails, such as those for cable trams.

Description

Rail Grinding Apparatus

FIELD OF INVENTION

This invention relates to maintenance of railways, and in particular to grinding of a running surface of the rail.

BACKGROUND OF INVENTION

For train operations, a smooth-running surface of the rail is necessary to minimize reaction dynamic force at the wheel-rail interface, thus reducing rolling noises from the train rail and wheels. The smooth-running surface is maintained by rail grinders, which conventionally are rail vehicles or trains consisting of a grinding equipment vehicle pulled by a locomotive. The rail grinders also help remove rusts from the surface of the rail.

There are different types of commercial rail grinders. One type of rail grinder has multiple rotational grinding stones, typically in the number of sixteen to thirty-two grinding stones, which are digitally controlled, where 1) the grinding depth is controlled by the rotation speed and grinding pressure of the grinding stones, and 2) the rail profile uniformity is controlled by aiming angle (s) of the grinding stones. The rail grinders are suitable for large scale grinding on horizontal rail alignment with slope less than 10°. However, these machines are not suitable for slope track and non-economical for short section grinding, due to the cost of transportation.

On the other hand, portable grinding machines are commonly used for smoothing the rail running surfaces at wedding joints. Typical portable grinding machines are weighted around 50 -100kg with a single rotational grinding stone, and can be operated by a sole worker. The grinding depth depends on the compression force and rotation speed of the grinding stone. The compression force is provided by the weight of the machine, and additional compression force from the worker should be avoided due to the concern of causing uneven grinding. The grinding depth and aiming angle are manually controlled by individual workers. As a result, the grinding quality (i.e., rail surface uniformity) is largely affected by human factors, quality control procedures, and executions.

Both types of conventional rail grinders introduced above are not suitable for steep rail alignment. Some rail grinders are equipped with grinding heads which are rotationally driven and powered by heavy machines. In one example, the rail grinder with its driving locomotive is as heavy as a hundred tons or more. In the case of a steep slope (>10°) , especially in tram rails, conventional rail grinders cannot be used due to the heavy weight and safety issues. The portable rail grinder is also unpractical for steep rail alignment when the rail alignment slope is greater than 10°, such as those for cable trams.

SUMMARY OF INVENTION

Accordingly, the present invention, in one aspect, is a rail grinding apparatus which includes a first grinding head adapted to at least partially contact a running surface of the rail, and a magnetic component for connecting the rail grinding apparatus to the rail via a magnetic attracting force. The first grinding head is rotatable in order to grind the running surface. A magnetic attraction force generated by the magnetic component presses the first grinding head to onto the running surface of the rail.

In some embodiments, the magnetic component is a permanent magnet or a solenoid.

In some embodiments, the first grinding head contains a ferromagnetic material.

In some embodiments, the rail grinding apparatus further contains a second grinding head aligned with the first grinding head along a length direction of the rail when the rail grinding apparatus is supported on the rail.

In some embodiments, the rail grinding apparatus further includes a second grinding head aligned with the first grinding head along a transverse direction of the rail when the rail grinding apparatus is supported on the rail.

In some embodiments, the rail grinding apparatus further includes a diamagnetic material or a paramagnetic material positioned between the first and second grinding heads.

In some embodiments, the rail grinding apparatus further includes a frame wherein the frame adapted to be supported on a rail in a slidable manner. The first grinding head and the magnetic component are connected to the frame.

In some embodiments, the first grinding head includes a cylindrical grinding wheel which at its bottom defines a flat circular grinding surface.

In some embodiments, the first grinding head is orientated in such a way that the flat circular grinding surface partially contacts the running surface of the rail at the interface. The cylindrical grinding wheel rotates when the rail grinding apparatus moves along the rail.

In some embodiments, cylindrical grinding wheel defines a rotational axis about which the first grinding head rotates. The rotational axis is offset from a normal line to an interface between the running surface and the first grinding head, when the rail grinding apparatus is supported on the rail.

In some embodiments, the flat circular grinding surface acts on a laterally converse surface of the rail when the rail grinding apparatus moves along the rail.

In some embodiments, the rail grinding apparatus is non-self-propelled.

In some embodiments, the first grinding head is motorless.

In some embodiments, the first grinding head contains a metal bond diamond grinding surface.

There are many advantages to the present invention. The rail grinding apparatus according to embodiments of the invention is a lightweight rail grinder, which is particularly suitable for using on steep rails, such as those for cable trams. The lightweight rail grinding apparatus is also useful and in fact more economic for small scale rail grinding, such as on testing tracks for train noise commissioning, short section rail alignment close to sensitive buildings, etc.

The foregoing summary is neither intended to define the invention of the application, which is measured by the claims, nor is it intended to be limiting as to the scope of the invention in any way.

BRIEF DESCRIPTION OF FIGURES

The foregoing and further features of the present invention will be apparent from the following description of embodiments which are provided by way of example only in connection with the accompanying figures, of which:

Fig. 1 is a perspective view of a rail grinding apparatus as positioned on a rail according to a first embodiment of the invention.

Fig. 2 shows a partial enlarged view of a grinding head in the grinding apparatus in Fig. 1, and the interface between the grinding head and a running surface of the rail.

Fig. 3 is a cross-sectional view of the grinding head in Fig. 2, as it partially contacts the running surface of the rail.

Fig. 4 is a perspective view of a rail grinding apparatus including laterally aligned grinding heads as it is positioned on a rail, according to another embodiment of the invention.

Fig. 5 is a cross-sectional view of a rail grinding apparatus including a magnetic component as it is positioned on a rail, according to another embodiment of the invention.

Fig. 6 shows a grinding head of a rail grinding apparatus and material of the grinding head according to another embodiment.

Fig. 7 is an illustration of a magnetic flux through two grinding heads of a rail grinding apparatus and a rail according to another embodiment of the invention.

Fig. 8 is a planar view of a rail grinding apparatus with two grinding heads and a diamagnetic material as the rail grinder apparatus is supported on a rail, according to another embodiment of the invention.

Fig. 9 is a cross-sectional view of a rail grinding apparatus as positioned on a rail according to another embodiment of the invention.

In the drawings, like numerals indicate like parts throughout the several embodiments described herein.

DETAILED DESCRIPTION

In the claims which follow and in the preceding description, except where the context requires otherwise due to express language or necessary implication, the word “comprise” or variations such as “comprises” or “comprising” is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.

Terms such as “horizontal” , “vertical” , “upwards” , “downwards” , “above” , “below” and similar terms as used herein are for the purpose of describing the invention in its normal in-use orientation and are not intended to limit the invention to any particular orientation.

Figs. 1-2 show a rail grinding apparatus 20 according to a first embodiment of the invention which is suitable for positioning on a rail 28 and moving along the rail 28 in a slidable manner. The rail 28 has a typical flat-bottom profile that is standard to most modern railway systems in the world. The rail 28 has a foot 28c, a web 28b, and a head 28a. The rail 28 is formed with a laterally converse surface at the top side of the head 28a. The laterally converse surface consists a central portion that has a substantially flat shape with a relatively small slope, known as a running surface 28d of the rail 28. Extending from both ends of the running surface 28d, the laterally converse surface then converges downward to form two substantially vertical surfaces known as gauge faces 28e, and the corner as a transition between each of the gauge faces 28e and the running surface 28d is known as a gauge corner 28f. As skilled persons would understand, the running surface 28d is the major portion of the rail 28 that supports wheels of trains (not shown) and at which rolling contact between the wheel and the rail 28 takes place.

As shown in Figs. 1-2, the top side of the head 28a is suitable for the rail grinding apparatus 20 to rest thereon. The rail grinding apparatus 20 includes a frame 24 which in the embodiment of Fig. 1 is shown in a cubic shape, and multiple grinding heads 22 mounted on the frame 24. In particular, the grinding heads 22 are positioned at a lower portion of the frame 24 such that grinding surfaces (not shown in Fig. 1) of the grinding heads 22 could act on the running surface 28d of the rail 28. In the exemplary embodiment of Fig. 1, there are shown three grinding heads 22 which are aligned along a length direction of the rail 28. Each one of the grinding heads 22 contains a cylindrical grinding wheel 22a that is rotatable around its rotating axis 26 that passes through a center of the cylindrical grinding wheel 22a. Each cylindrical grinding wheel 22a is rotational symmetric about its rotating axis 26. The rotating axis 26 does not overlap with a vertical central line (not shown) of the rail 28. For each grinding heads 22, the cylindrical grinding wheel 22a is movably supported on the frame 24 through mechanical structures (not shown) such as a hinge, a bearing, etc. It should be noted that in this embodiment, the cylindrical grinding wheel 22a is motorless, as the cylindrical grinding wheel 22a are not driven to rotate by a motor or any other active driving parts or energy source in the rail grinding apparatus 20. Rather, as will be mentioned in details below, the cylindrical grinding wheel 22a rotates to grind the running surface 28d in a passive manner, when the rail grinding apparatus 20 moves along the rail 28.

A closer look at a grinding head 22 and its contact with the running surface 28d is shown in Fig. 2. The grinding heads 22 in the rail grinding apparatus 20 each have a flat circular grinding surface 22b that is defined at the bottom side of the cylindrical grinding wheel 22a. As shown in Figs. 1-2, the cylindrical grinding wheels 22a are not located at the center of the rail 28 in a lateral direction thereof. Rather, each cylindrical grinding wheel 22a is positioned closer to one of the gauge corners 28f than the other. As such, the flat circular grinding surface 22b does not entirely contact the running surface 28d of the rail 28, but instead the flat circular grinding surface 22b partially contacts the running surface 28d of the rail 28.

The rail grinding apparatus 20 is a non-self-propelled device, and in other words there is no driving means or any energy source for this purpose which is configured on the rail grinding apparatus 20. Rather, the rail grinding apparatus 20 is driven to move along the rail 28 by a driving unit (not shown) that is physically separated or connected to the grinding device, and for example the driving unit may be a locomotive, train, trolley or winch, etc.

Having described the structure of the rail grinding apparatus 20, the descriptions now go to the working principle of the rail grinding apparatus 20. The grinding operation of the rail grinding apparatus 20 helps smooth surface roughness and/or re-profile the running surface 28d of the rail 28 for train and tram operation, or similar activities. Fig. 3 best illustrates how the grinding heads 22 in the rail grinding apparatus 20 operate to grind the rail 28. As mentioned above, the flat circular grinding surface 22b partially contacts the running surface 28d of the rail 28, and as shown in Fig. 3 more than half of the area of the flat circular grinding surface 22b does not touch the running surface 28d. In the cross-sectional view in Fig. 3, the grinding head 22 thus has its one end higher that another end. A grinding contact area 30 of the cylindrical grinding wheel 22a contacts a portion of the running surface 28d near a gauge corner 28f, and at the center of the grinding contact area 30 a normal reaction force 32 at the interface between the grinding head 22 (and thus the cylindrical grinding wheel 22a) and the rail 28 acts on the cylindrical grinding wheel 22a. The normal reaction force 32 is offset from the rotational axis 26 of the cylindrical grinding wheel 22a. The normal reaction force 32 acts on the cylindrical grinding wheel 22a in an non-uniform way because most of the area of the flat circular grinding surface 22b is not subjected to the normal reaction force 32. As a result, when the rail grinding apparatus 20 moves along the rail 28, because of the unbalanced sliding friction at the flat circular grinding surface 22b, the cylindrical grinding wheel 22a is made to rotate by the rail 28 (and in particular by the sliding friction at the grinding contact area 30) , thus grinding the running surface 28d. In other words, automatic rotation of the cylindrical grinding wheels 22a are achieved even if there is no mechanical power source like a motor. The automatic rotation helps heat dissipation and throws away accumulated grinding materials attached to the grinding surface.

It should be noted that although Fig. 3 only shows the grinding made on one end of the running surface 28d, it is possible to change the orientation of the rail grinding apparatus 20 (e.g. flipping the rail grinding apparatus 20 on the lateral direction of the rail 28) so that the rail grinding apparatus 20 could grind the portion of the running surface 28d at another end.

Fig. 4 shows another embodiment of the invention in which a rail grinding apparatus 120 contains three grinding heads 122 each in the form of a cylindrical grinding wheel that are aligned along a lateral direction of rail 128. In this configuration, the three grinding heads 122 simultaneously grind different portions of a running surface 128d of the rail 128. The middle grinding head 122 among the three has a larger grinding contact area (not shown) with the running surface 128d as compared to the two other grinding heads 122, and this is because of the relatively smaller slope at the center of the running surface 128d as compared to its two ends near gauge corners 128f. The multiple grinding heads 122 are integrated in a single rail grinding apparatus 120, resulting in a compact design. The normal axis (not shown) of each grinding head 122 aligns with a normal direction of the running surface 128d at different portions of the running surface 128d, in order to maintain the profile of the running surface 128d of the rail 128. As a result, as shown in Fig. 4 the rotational axes 126 of the three grinding heads 122 are not parallel to each other.

Turning to Fig. 5. In another embodiment of the invention, a rail grinding apparatus 220 contains a frame 224 which in the embodiment of Fig. 5 is shown in a rectangular shape in the cross-sectional view. The frame 224 is connected with a magnetic component 234, and in particular the magnetic component 234 is located within the frame 224 and above a grinding head 222 positioned at a lower portion of the frame 224. The magnetic component 234 for example could be a permanent magnet or a solenoid. A grinding surface 222b of the grinding head 222 could act on a running surface 228d of a rail 228.

Having described the structure of the rail grinding apparatus 220, the descriptions now go to the working principle of the rail grinding apparatus 220. The rail grinding apparatus 220 because of the embedded magnetic component 234 can be magnetically attached to the rail 228 where a grinding pressure is mostly contributed by the magnetic attraction force. The grinding head 222 is pressed to the rail 228 by the magnetic attraction force, and the magnetic attraction force results in a normal force 236 (as a pair of force of action and reaction) for grinding the running surface 228d at the interface between the grinding head 222 and the running surface 228d of the rail 228. The magnetic component 234 is positioned such that the magnetic attracting force is substantially normal to an interface between the running surface 228d and the grinding head 222, when the rail grinding apparatus 220 is supported on the rail 228. The magnetic component 234 provides the magnetic field necessary for the grinding head 222 to be pressed onto the running surface 228d of the rail 228. The amount of the magnetic force can be adjusted by adding or removing permanent magnets in case the magnets are used, or by adjusting the current in the solenoid in case the solenoid is used.

In a preferred embodiment as shown in Fig. 6, a grinding head 322 of a rail grinding apparatus (not shown) is made of a ferromagnetic material 338 which would increase the magnetic attraction force by magnetization of the grinding head 322 and a rail 328.

Turning to Fig. 7, in which a grinding apparatus 420 containing two grinding heads 422 is illustrated to be supported on top of a rail 428, where a magnetic flux loop 440 formed by a magnetic component 434 of the grinding apparatus 420 is also illustrated. The magnetic flux loop 440 passes through the two grinding heads 422, the magnetic component 434, and the rail 428 in an anti-clockwise sense.

Fig. 8 shows another embodiment of the invention in which a grinding apparatus 520 containing two grinding heads 522 is illustrated to be supported on top of a rail 528. What is different in the configuration of Fig. 8 as compared to that in Fig. 7, is that the grinding apparatus 520 additionally contains a diamagnetic material 542 located under a magnetic component 534 and between the two grinding heads 522. The diamagnetic material 542 is placed within a magnetic flux loop (not shown in Fig. 8) generated by the magnetic component 534, in order to increase the flux density passing through the grinding heads 522. In an alternative embodiment, a paramagnetic component is used instead of the diamagnetic material 542. As skilled persons in the art understand, diamagnetic materials such as cooper and silver are those with weak and negative magnetic susceptibility, and they slightly repel when subjected to an external magnetic field. As such, diamagnetic materials do not allow a magnetic flux to be formed in a certain direction. Ferromagnetic materials, such as iron and nickel, have high magnetic susceptibilities. They are strongly influenced by an external magnetic field and retain their magnetic properties even if the magnetic field's source is removed. As such, ferromagnetic materials allow a magnetic flux to be formed in a certain direction. Lastly, paramagnetic materials have smaller magnetic susceptibilities than ferromagnetic materials. Unlike diamagnetic materials, the value of magnetic susceptibilities of paramagnetic materials is positive but only slightly greater than zero. Even if they are slightly attracted to an external magnetic field, they do not retain their magnetic properties when the source of the magnetic field is removed. Examples of such materials are magnesium and lithium.

It should be noted that the configurations shown in Figs. 7 and Fig. 8 could either be made across a lateral (transverse) direction of a rail, or a length direction of a rail. In the former case, the two grinding heads shown in Fig. 7 or Fig. 8 are aligned along the lateral direction and the length direction of the rail is thus substantially perpendicular to the magnetic flux loop. In the latter case, the two grinding heads shown in Fig. 7 or Fig. 8 are aligned along the length direction and the lateral direction of the rail is thus substantially perpendicular to the magnetic flux loop.

The structure of individual grinding heads in the embodiments of Figs. 5-8 could be the same as those in Figs. 1-4, or the grinding heads can have a different structure and working principle. In one implementation, the grinding heads are motorless, and are in the form of cylindrical grinding wheels like that in Fig. 3. In another implementation, the grinding heads may be driven by a motor in the rail grinding apparatus.

Fig. 9 shows another embodiment of the invention, in which a grinding apparatus 620 combines both the magnetic component and the unbalanced cylindrical grinding wheel in previous embodiments. In particular, the grinding apparatus 620 contains a frame 624, and both a magnetic component 634 and a cylindrical grinding wheel 622a are connected to the frame 624. The magnetic component 634 is placed above the cylindrical grinding wheel 622a. When the grinding apparatus 620 is properly positioned on a rail 628, the rotational axis (not shown) of the cylindrical grinding wheel 622a does not overlap with the vertical central line of the rail 628. The rotational axis is also offset from a normal reaction force (not shown) at the center of the grinding contact area that is at an interface between the cylindrical grinding wheel 622a and the rail 628. The cylindrical grinding wheel 622a is a non-powered rotational grinding head similar to that in Fig. 3. A magnetic attraction force 636 is generated by the magnetic component 634 and pulls the cylindrical grinding wheel 622a toward the rail 628.

The exemplary embodiments are thus fully described. Although the description referred to particular embodiments, it will be clear to one skilled in the art that the invention may be practiced with variation of these specific details. Hence this invention should not be construed as limited to the embodiments set forth herein.

While the embodiments have been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only exemplary embodiments have been shown and described and do not limit the scope of the invention in any manner. It can be appreciated that any of the features described herein may be used with any embodiment. The illustrative embodiments are not exclusive of each other or of other embodiments not recited herein. Accordingly, the invention also provides embodiments that comprise combinations of one or more of the illustrative embodiments described above. Modifications and variations of the invention as herein set forth can be made without departing from the spirit and scope thereof, and, therefore, only such limitations should be imposed as are indicated by the appended claims.

It is to be understood that, if any prior art publication is referred to herein, such reference does not constitute an admission that the publication forms a part of the common general knowledge in the art, in Australia or any other country.

The material of the grinding head at the grinding surface can be any suitable grinding material, and it can be different from the material (s) of the rest of the grinding head. In one embodiment, the rotatable grinding head of the rail grinding apparatus includes a metal bond diamond grinding surface.

The embodiments in Figs. 1-4 and 7-8 illustrate rail grinding apparatuses with multiple grinding heads (e.g., two to three) . It should be noted that there is no limitation to the number of grinding heads (e.g., cylindrical grinding wheels) in a rail grinding apparatus. Rather, depending on the practical application any suitable number of grinding heads may be configured.

Claims

A rail grinding apparatus, comprising:

a first grinding head adapted to at least partially contact a running surface of the rail; and

a magnetic component for connecting the rail grinding apparatus to the rail via a magnetic attracting force;

wherein a magnetic attraction force generated by the magnetic component presses the first grinding head to onto the running surface of the rail.
The rail grinding apparatus of claim 1, wherein the magnetic component is a permanent magnet or a solenoid.
The rail grinding apparatus of claim 1 or 2, wherein the first grinding head comprises a ferromagnetic material.
The rail grinding apparatus of any one of the preceding claims, further comprises a second grinding head aligned with the first grinding head along a length direction of the rail when the rail grinding apparatus is supported on the rail.
The rail grinding apparatus of any one of the claims 1-3, further comprises a second grinding head aligned with the first grinding head along a transverse direction of the rail when the rail grinding apparatus is supported on the rail.
The rail grinding apparatus of claim 4 or claim 5, further comprises a diamagnetic material or a paramagnetic material positioned between the first and second grinding heads.
The rail grinding apparatus of any one of the preceding claims, further comprises a frame wherein the frame adapted to be supported on a rail in a slidable manner; the first grinding head and the magnetic component connected to the frame.
The rail grinding apparatus of any of the preceding claims, wherein the first grinding head comprises a cylindrical grinding wheel which at its bottom defines a flat circular grinding surface.
The rail grinding apparatus of claim 8, wherein the first grinding head is orientated in such a way that the flat circular grinding surface partially contacts the running surface of the rail at a portion of the flat circular grinding surface away from the center of the flat circular grinding surface; the cylindrical grinding wheel rotating when the rail grinding apparatus moves along the rail.
The rail grinding apparatus of claim 8, wherein the cylindrical grinding wheel defines a rotational axis about which the first grinding head rotates; the rotational axis being offset from a normal line to an interface between the running surface and the first grinding head, when the rail grinding apparatus is supported on the rail.
The rail grinding apparatus of claim 8, wherein the flat circular grinding surface acts on a laterally converse surface of the rail when the rail grinding apparatus moves along the rail.
The rail grinding apparatus of any one of the preceding claims, wherein the rail grinding apparatus is non-self-propelled.
The rail grinding apparatus of any one of the preceding claims, wherein the first grinding head is motorless.
The rail grinding apparatus of any one of the preceding claims, wherein the first grinding head comprises a metal bond diamond grinding surface.