Patent Application
20240426062
The present application is based upon and claims the right of priority to European Patent Application No. 23180485.7, filed on Jun. 20, 2023, the disclosure of which is hereby incorporated by reference herein in its entirety for all purposes.
The invention relates to the field of mobile treatment of rails with an abrasive rail planning module comprising of one or more abrasive blocks which are in contact with the rail. In particular the present invention relates to the field of mobile rail treatment wherein the abrasive blocks are pressed onto the rails by an eccentric drive. The related technology—for instance integrated into a vehicle or module—allows for removing rail surface irregularities such as corrugations, near surface defects, and millscale.
Steel wheels from trains running on steel rails cause for wear and fatigue damage to both components. Wear and fatigue damage on rails mainly occur on the head and shoulders of the rails. High traction forces, acceleration and/or deceleration and curving of trains all contribute to the occurrence of such wear and rolling contact fatigue damages. For extending the life of rails, a minimization of damages to a related track and/or vehicle components as well as a minimization of noise and vibration, which are issues to passengers and nearby residents, are required. It is therefore necessary that rails are maintained.
To avoid a replacement of entire rails with surface irregularities such as corrugations, near surface defects and millscale, a maintenance is often performed by on-site treatment of rails. Therefore, often a wagon is equipped with grinding tools which allow metal removal by, for instance, grinding or milling of the rail surface with the help of stones performing movements to remove metal. The related abrasive blocks are usually connected to a drive which performs oscillating movements. Rotational grinding, oscillating block grinding, planing, milling and rotational planing are all common mobile rail treatment methods used to either bring rails in shape or keep rails in shape. Each of these methods have their specific advantages and disadvantages.
Often ridges and irregularities can be removed from rail head surfaces by means of a travelling on-track planing, shearing and grinding machine with related tool supports. The tool supports provided for each rail are typically pivotally interconnected through spacers adjustable in length transversely of the longitudinal axis of the machine. A set of tools is arranged opposite one another for each rail. The tool support is provided with guide rollers guided firmly along the upper surface and outside of the rail head. The known drives for grinding usually have a relatively small stroke which is often tried to be compensated by higher frequencies or forces with which the abrasive block is pressed onto the rail.
The machining tools and related machines for rail treatment usually leave the removed metal on or next to the rail. Hence all debris—including a mixture of water, dust, abrasive residue and metal—produced by the existing technologies stays behind on the tracks which requires additional and subsequent cleaning in case of rails surrounded, for instance, by asphalt. In existing grinding machines a relatively short longitudinal or sliding movement of a grinding block is performed due to the nature of the rotational to linear movement mechanism which often means debris remains between stone and rail and is not cleared which in turn results in low metal removal.
In existing machines often multiple blocks are fitted in a sort of moving ruler or bar and grinding blocks can only be fitted straight, but not angled. This results in low flexibility also in relation to the allowed surface shapes of the rail heads and the way they can be treated. The grinding blocks also cannot be pressed on the rail individually, but only in a fixed series of blocks.
The existing rail grinding technology only works with the use of significant amounts of water for cooling the stones, typically this technology requires a few thousands of liter water to function, water is sprayed ahead and behind each grinding stone. Hence, significant amounts of water are wasted.
Rotational to linear movement mechanism is often achieved through gearboxes with excenter mechanisms, for instance a Latest Plasser system via linear horizontal hydraulic cylinders and/or actuators. These are typically used on tramway systems.
The patent DE3015283A1 describes a travelling on-track machine for removing irregularities from the rail head surface of laid rail tracks and further relates to a method for removing irregularities, such as ridges and laps, from the rail head surface of at least one rail of a laid track using a plane carriage which is pivotally connected to the planing machine and designed to be vertically and laterally guided along the rail head and which is provided with only one planing tool per rail. Hence a significant removal of metal and thus a faster, but also more flexible approach related to the surface shape remains a challenge.
It is an object of the invention to provide a method and a related machine for mobile rail treatment with improved characteristics.
According to the invention, this object is addressed by the subject matter of the independent claims. Preferred embodiments of the invention are described in the sub claims.
The invention aims inter alia in improving the rail's longitudinal profile combining both high metal removal with leaving a very low residual roughness from the machining process and without leaving any significant dust and/or debris on the track. Further, the invention improves mobile rail treatment by using a method which does not produce any sparks.
According to the invention a vehicle for machining a rail by grinding and/or planning is provided, comprising a metal abrasive module, an eccentric drive performing an eccentric movement, at least two abrasive blocks connected with the eccentric drive, and a force exerting drive pressing at least one abrasive block onto the rail, wherein the metal abrasive module and/or at least one of the abrasive blocks is—preferably individually—tiltable around an axis parallel to the rail, and wherein at least one of the abrasive blocks is individually pressable onto the rail. The invention also provides a machining technology for mobile rail treatment which is suitable for implementation in a vehicle or train.
The invention allows for high performance mobile rail treatment suitable for removing rail surface irregularities such as corrugations, near surface defects and millscale. Furthermore, high metal removal capabilities combined with leaving a very low residual machining roughness are achieved by the invention. An abrasive block tiltable around an axis parallel to the rail allows a complex machining of the metal surface and therefore—related to rails—the head and/or shoulder. The metal removal can therefore be performed individually and better adapted to the local form or desired form. This can allow to shape rails to complex forms or profiles with the shape of individual curves.
In case the abrasive blocks are individually pressable onto the rail, the aforementioned advantages related to the tiltable abrasive blocks apply here as well—the individually pressable abrasive blocks support shaping the rail's surface to an individual form. The invention also provides a machining technology for mobile rail treatment which is suitable for implementation in a vehicle or train.
The vehicle may also be a wagon or a train car or another mobile service car including those used for trams and/or trains or other rail bound vehicles. The abrasive block may comprise a hard material in form of a stone and/or crystal and/or ceramic and/or a material compound including several materials. The abrasive block can be manufactured by pressing, casting, hot embossing or other methods allowing to produce a block that is hard and/or stable enough for removing metal from a rail by grinding and/or planning. Further, the abrasive block basically can have a relatively simple outer geometry in form of a cuboid, but a free-formed, individually designed geometry can be of advantage especially when considering special forms of the rail surface.
The eccentric drive usually comprises a drive which is coupled to a turning motor, wherein the eccentric drive transforms the oscillation or other motion of the motor into eccentric movements.
In one embodiment of the invention, a translational movement component of at least one of the abrasive blocks is longer than the length of said abrasive block. In this way the removed metal, which may often stay between the rail and the abrasive block for several periods of the oscillating movement of the abrasive block, is moved faster to the sides of the abrasive block. Hence the removal rate of the mobile rail treatment is increased since the abrasive block is more in direct contact with the rail surface.
In one embodiment of the invention, the eccentric movement has a scotch yoke type mechanism. The Scotch Yoke is a reciprocating motion mechanism which transforms the linear motion of a slider into rotational motion or vice versa. The piston or other reciprocating part is directly coupled to a sliding yoke with a slot that engages a pin on the rotating part. The location of the piston versus time typically is a relatively simple harmonic motion, for instance a sine wave having constant amplitude and constant frequency which produces a constant rotational speed. The advantage of a scotch yoke type mechanism can be the realization of a high amplitude—especially of the translational component of the movement—and/or a high acceleration and/or a high pressure and/or a high velocity, which may all contribute to an increased removal rate of metal of the rails.
In another realization of the invention multiple abrasive blocks are coupled together which can therefore work as a sliding ruler. Typically, every further added abrasive block increases the length of the rail which can be treated simultaneously. However, it is also advantageous to limit the length of each abrasive block so that removed metal is moved more efficient to an outside of an abrasive block. Hence, it is advantageous to limit the overall length of each abrasive block and use multiple abrasive blocks which can also be positioned individually
In a preferred embodiment of the invention, the eccentric drive is driven by a variable frequency electric motor and/or a hydraulic drive. A variable frequency electric motor allows for adjustment of the power and rounds per minute and hence the rotational speed. Further these can be relatively efficient in power consumption. A hydraulic drive is often already available and therefore, no extra motor or drive is required.
In a further realization of the invention the abrasive module can be tilted from vertical towards an outer side and/or inner side of the rail. This allows, e.g., for shaping the head and/or the shoulder of a rail. Conventional system in state of the art allow only a fixed angle towards the rail which reduces the possibilities to efficiently reshape rails.
In a special embodiment of the invention, the vehicle and the abrasive module further comprises a debris suction head in the vicinity of the contact surface of the metal abrasive module with the rail. This allows to remove at least most of the removed metal from the rail and no or only little of the removed metal is left in the vicinity after treatment of the rail.
Further it is preferred that the invention comprises a guide roller in the vicinity of the metal abrasive module and/or abrasive block, wherein the guide roller is in contact with the rail allowing i. a. for machining rails in tight curves. The guide roller may also contribute to less vibrations of the system and it may also comprise an opening near the surface of the rail for suction of removed metal.
In a further realization of the invention at least two abrasive modules are each connected to an individual guide roller. This can significantly improve the quality of the guiding mechanism, improve security measures etc. and hence allow narrow curves.
It is further preferred that the abrasive module is connected to a guide roller with a—preferably integrated—debris suction head. The suction head can be located in front or in the rear of the guide roller and. It can also be thought of—preferably multiple—suction heads or channels, which—in a special embodiment—may be distributed and/or integrated around the guide roller.
The invention further comprises a method for machining a rail by grinding and/or planing, comprising the steps of approaching a surface to be machined until contact with a metal abrasive module with at least two abrasive blocks connected with a vehicle, tilting the metal abrasive module and/or at least one abrasive block parallel to a desired surface form, performing eccentric movements with the metal abrasive module while pressing the metal abrasive module onto the rail.
The method can further comprise the step of suction of debris and/or metal chips in the vicinity of at least one of the abrasive blocks. By this an improved removal of the removed metal can be realized.
These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter. Such an embodiment does not necessarily represent the full scope of the invention, however, and reference is made therefore to the claims and herein for interpreting the scope of the invention.
In the drawings:
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The metal abrasive module 2 is schematically depicted in
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While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive; the invention is not limited to the disclosed embodiments. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be construed as limiting the scope. Further, for the sake of clearness, not all elements in the drawings may have been supplied with reference signs.
| Number | Date | Country | Kind |
|---|---|---|---|
| 23180485.7 | Jun 2023 | EP | regional |
