EP2886714B1 - Deflector plate with protective layer for a track grinding machine - Google Patents

Description

The present invention relates to a device for grinding rails in the track during a crossing with the features of the preamble of claim 1.

Tracks laid in the track are subject to noticeable wear due to the constant crossings of fast-moving and / or heavy-weight trains. This wear manifests itself initially in a scoring or ribbing as well as in the formation of microcracks. If this wear is not counteracted by regular maintenance, then it can develop into a massive damage to the rails and thus pose a considerable risk to the safety of further rail traffic, up to the risk of a rail break and consequent derailment.

In order to prevent such hazards and to counteract the wear or to overhaul worn-out rails and reprofile, a grinding process of the surface of the rails, in particular the running surface and driving edges, is carried out today as a possible method. Such grinding operations are particularly for modern high-speed lines, such as those of the German ICE, the French TGV or the Japanese Shinkansen be used. Since such grinding operations are performed on the rails laid in the track, which of course can not be removed separately from the track for such overtaking and ground stationary in a grinding station, so-called grinding cables are typically used. These grindstones have abrasive grinder assemblies, often held in abrasive racks, which are lowered onto and guided over the rail surface.

Here are two basic principles of grinding: those with grinding wheels that are actively driven by a drive for rotation and are moved by this typically applied by a drive motor driving force relative to the rail surface and so unfold the abrasive effect, and those in which the grinding wheels are freely rotating and suspended without their own drive and are offset only due to the locomotion of the grinding device on the rail and by an inclination of the axis of rotation relative to the rail longitudinal direction in rotation and thus produce the grinding action.

For the first variant both cup grinding bodies come into consideration, which rotate about a longitudinal axis, which is applied substantially perpendicular to the rail surface, but also peripheral grinding bodies with rotation axes, which are guided in a plane substantially parallel to a grinding surface. A possible example of such systems with driven abrasive bodies is in the EP 0 843 043 A1 disclosed.

An operating according to the second principle of the non-actively driven abrasive grinding device or such a grinding is in the EP 0 708 205 A1 described. There, the grinding wheels are rotationally symmetrical formed as a peripheral grinding and rotate about a grinding body axis of rotation, without being driven by a motor or the like. Drive to such a rotation. With the peripheral grinding bodies lowered onto the rail surface and pressed against them, the grinding train now moves forward, the circumferential grinding bodies being set at an acute angle to the rail longitudinal direction with their axes of rotation, thus by a relative movement to a rotation be driven while unfolding a grinding action and get a corresponding removal of the worn surface of the rail. Unlike when working with actively driven grinding wheels, which allows traveling speeds of the grinding trains only in the range of tempo, working on the second principle grinding train can move at a comparatively high speed; Here, speeds of about 80 km / h can be achieved.

Regardless of the grinding principle employed, such a rail machining operation has the problem that abrasive particles are expelled from the working surface, typically outward transverse to the direction of travel. These abrasive particles consist on the one hand of steel particles which are ground off the rail surface, on the other hand particles of the abrasive article, e.g. Corundum or particles of the binder mass connecting the abrasive bodies, e.g. a resin. These abrasive particles are very hot due to the grinding process and the high temperatures generated by the high friction during this processing, not infrequently are thrown as glowing sparks from the grinding point.

On the one hand to prevent entry of this material into the environment per se, on the other hand, but especially to counter fire hazards and other hazards due to the sparks as hot sparks in the environment, known device for grinding rails in the track during a crossing means for interception or retention of these particles, these means are often formed by shielding.

Thus, the applicant himself after the in the EP 0 708 205 A1 described abrasive grinding ago and has those in use, where appropriate shielding in the form of baffles are arranged on the side of the grinding wheel assemblies and operation right and left to be ground rail, which baffles are lowered in operation to the level of the rail and this rail as possible enclose sealing, without, however, abut on this. These baffles are currently made of metal, partly made of stainless steel, since this material both the mechanical loads must be able to withstand the high-energy and high-impulse particles, as well as the high thermal loads. Because the temperature at which the sparks and abrasion particles flow against the parallel plates, is often at 1,000 ° C and above.

However, it has now been found that the use of metal, in particular a stainless steel for the material of the baffles poses problems:

For example, a corresponding baffle made of stainless steel due to the high thermal load (the baffle heats up considerably due to the impinging hot sparks, sometimes to red hot) increased wear of the baffles. In particular, the material warps and rejects, so that it no longer has the flat and planar shape of a predetermined shape sheet after a short service life, but deviates from this planar shape in an unpredictable manner. In particular, since the area in which the corresponding baffles can be carried in an outer space of the track, so beyond the outer edge of the track laid in the track, the so-called light space is very narrow, can occur here distortions and deformations of the baffles cause that here the light space is further injured, it is possible collisions with arranged in the track bed rail facilities, eg Sensors or switching elements, comes. Also, a dense as possible sealing of the space in which the debris and sparks arise worsened, so that possibly increased abrasion particles and sparks can get into the environment, form an undesirable material entry and possibly, if the material is still there in strong heat , cause a fire hazard.

Accordingly, the known steel baffles must be replaced comparatively frequently, have only short lifetimes, which makes the operation and maintenance of a corresponding device significantly more expensive, not only because of the fact to be retrofitted baffles, but also because of the associated downtime and downtime of the device ,

Made of a stainless steel baffles have also proved to be disadvantageous for another reason. In various railway networks, such as in the railway network of the German Federal Railroad, magnetically operating sensors are arranged, the wheels of passing trains due to the magnetic properties of metallic wheel tires recognize and perceive, the so-called wheel counter. With these individual sections are monitored, and it is in particular adjusted whether a train that has been detected with a counted number of wheels on a first section, with the corresponding number of wheels in a subsequent section, in which this should be transferred, arrives. If there is a difference, a warning is issued in the railway network, which is displayed to the route control and operating personnel, the action requires, up to a blockage of the route section in question. In this way, e.g. Trolley derailments or uncoupled cars are detected in time to prevent any accidents with remaining in the track car or the like.

It has now been found that such magnetic sensors also react to the baffles which are guided past them in the detection distance of the sensors and - not always reproducibly - trigger a wheel count. Thus, it can happen in particular and has also already occurred that count differences occur here, depending on how the sensors arranged in the track sections react to the baffles. Of course, such miscalculations and inaccuracies are considerably disturbing for the operation of the route network, so that improvements are required on the part of the railway network owners or operators.

The inventors have made various considerations and attempts in this regard. Attempts to achieve an improvement here with a non-ferromagnetic metal material as a replacement for the steel, have failed in terms of the miscounts of the so-called wheel counter. It has been found that even such material has caused misdetections in the sensors. Incidentally, no material improvements in the stability of the baffles could be achieved with such a material.

Further attempts of the inventors to act here with ceramic materials that are known to be heat resistant and do not react to the magnetic sensors also did not provide any breakthrough. In particular, it has been found that ceramic materials were just too susceptible to breakage in such devices for grinding rails or grinding trains, which worked on the principle of non-motorized grinding wheels and drive accordingly fast in the track. Although false signals of the magnetically acting sensors could be ruled out, even worse service lives resulted in accordance with a shielding elements equipped with a ceramic material or formed from such a material.

In the DE 100 20 314 C1 a rail grinder with means for dust and spark protection is disclosed. As means for dust and spark protection are used in the here disclosed, according to the first-described grinding principle working rail grinding, blinds, which are made of a heat-resistant, flexible plastic or rubber and sanding space side are provided with a non-flammable layer. More precise material information on the non-combustible layer are not mentioned in this Vorveröffentlichung.

To bring here an improvement, in particular to provide a device for grinding rails in the track during a crossing, which had improved shielding to the effect that they allow longer life and on the other preclude the influence of magnetic sensors in the track and these made incorrect measurements was Object of the present invention.

This object is surprisingly achieved by a device for grinding rails in the track during a crossing with the features of claim 1. Advantageous developments of such a device according to the invention are specified in the dependent claims 2 to 10.

The inventors have found after long series of experiments with very different materials that surprisingly laminate material made of a resin reinforced with mineral particles the high thermal and mechanical loads By approaching abrasion particles and sparks, as they arise during the grinding of rails laid in the track, with good robustness can withstand. Accordingly, it has turned out for a device that at least a shielding element, which has this device for retaining and intercepting abrasion particles formed during grinding, contains such a material at least on its surface exposed to a corresponding approach of abrasion particles and sparks. The device may advantageously contain a plurality of shielding elements formed in this way, in particular in such a way that they largely surround the track in the section in which the grinding takes place, at least in time so as to retain in a defined space the abrasive particles and sparks, which then can be sucked through a suction provided with advantage and retained in a known manner, for example with filter technology and can be eingeschunkert on the device for environmentally sound and professional disposal, or a possible reuse, if such offers itself.

In principle, the shielding element can also consist overall of the laminate material formed as described.

With particular advantage, the laminate material can be formed from silicone resin reinforced with mica particles. Here in particular a material in question and has been found to be very suitable, which is prepared by pressing several layers of silicone resin impregnated mica paper under high pressure and temperature. Applicants have made here with a ^"® K-Therm AS M" by the company AGK High Performance Materials GmbH of Dortmund, Germany, under the brand name available on the market material good experience, and specific to a particular material of this group called "K- has been resorted Therm ^® AS 600 M ". This material is a mica paper impregnated with silicone resin under high pressure and temperature produced laminate material. As a mica material of this type of different crystal structure come into play, in particular, the mixture Muskovite and phlogopites are included. This creates elements that are reinforced with mica fibers, these fibers or platelets included in a glassy matrix, wherein the overlaying of the impregnated papers a layered laminate structure is given. This material, which is offered by the manufacturer as a thermal and electrical voltage insulator, is designated by the manufacturer as suitable for operating temperatures up to 800 ° C and comes according to the manufacturer for use in thermal insulation panels for heated presses in wood and plastics processing, for electrical insulation and for electric arc furnaces, for insulating parts of induction systems, for wearing parts for hot glass transport as well as for electrical and thermal insulating components of various types.

For use as a material for shielding elements for intercepting and retaining abrasion particles and sparks resulting from the grinding of rails laid in the track during a passage, which impinges on the surface of the shielding element at temperatures well above 800 ° C. and high momentum is associated with US Pat Until then, nothing was known about this material, and the manufacturer was unable to give the inventors any positive opinion regarding the suitability of this material for such an application.

The inventors have nevertheless tested this material and found, as already mentioned, that a corresponding material surprisingly is excellently suitable for the stated purpose and also withstands the high temperatures of the inflowing sparks and particles, which are well above the maximum values of the manufacturer's specifications mechanical load. In particular, it has been shown that with shielding elements formed from or with corresponding material, far longer service lives of these elements can be achieved than is the case with the known baffle plates made of steel or other metallic materials. It has also been shown that the material not only withstands thermal and mechanical stresses due to the oncoming abrasion particles and sparks, but also the mechanical stresses that occur during the forward travel of a corresponding device for grinding rails in the track during a passage over the to be ground Rails and associated shocks go along. Especially in the case of the above illustrated second principle with non-motorized grinding wheels operating devices that travel comparatively quickly over the rails at speeds of eg 80 km / h, such mechanical stresses are high. However, this material was previously used only stationary, was not tested by the manufacturer in terms of its suitability in a dynamic use with corresponding mechanical loads, certainly not at such speeds as 80 km / h, and also not for such applications. Again, the inventors have stated that the material is very well suited, due to what, as the inventors suppose by the laminate structure, some flexibility with constant durabilty.

The material also affects non-track magnetically acting sensors, such as those found in the track. the wheel counter described above, so that caused due to the previously used metallic baffles miscalculations omitted.

In addition, a shield member formed or provided in the material composition according to the invention from the laminate material, which can be used in the apparatus for grinding rails in the track during a passage, may be substantially plate-shaped. The material, as obtained by the inventors of said manufacturer, has always been in the desired shape, typically manufactured as flat plate-like elements. It has also been found by experiments initiated by the inventors that this material can still be deformed after production as a laminate, e.g. by bending over edges. This is also a special property which makes the material suitable for use in the manner according to the invention, since thus gap-reducing end edges and offsets and the like structures can subsequently be introduced and shaped into corresponding material plates.

For the purposes as a shielding appropriate plate-shaped elements with material thicknesses of 5 to 20 mm, in particular from 6 to 15 mm are suitable. With such a material thickness, the shielding elements are sufficient sturdy, but also light and do not protrude excessively into the space next to the rail when used on the grinding machine.

If, as may be provided with particular advantage, an abrasive body of the device provided on both sides with an existing from the laminate material used according to the invention or equipped with such a material shielding, so advantageously the corresponding shielding formed from the shielding trough-like from the bottom upwards. In this case, in particular, an angle facing the respectively opposite shielding element can be provided on a lower edge of the elements facing the rails in order to leave a gap between the rail and the shielding element as small as possible. By means of such a trough-like and overall shielded construction of the shield, the resulting abrasion particles and sparks are retained with particular certainty and can be fed to or captured by an optional, but advantageous, suction for detecting the abrasive particles and sparks.

Advantageously, means are further provided for raising and lowering the at least one shielding element with which it can be held relative to the chassis in a lowered or raised position and moved therebetween. This may be of particular importance when in the track in the course of the rails to be processed obstacles, such as scissors of points, are located, where the shielding can not be passed in lowered and the shield forming state. Then, whether manually or triggered by a sensor system and corresponding signal processing, an affected shielding element can be lifted by the means and lowered again after passing through such a "blockade point". Although then occur in the area in which the shielding is raised, possibly some resulting during grinding particles or sparks in the environment, but the shielding itself is not endangered, can after driving over the short track section with the device be lowered again, then continue to serve a secure support and interception of the outgoing abrasion particles and sparks.

With particular advantage, the device in which the novel shielding element formed or provided with said laminate material is used is one which operates according to the second principle described above, that is, the one with an angle at an acute angle to the rail longitudinal direction and non-motorized grinding wheels works. In particular, in such a device, the use of the material chosen by the inventors for the shielding has proved to be of particular advantage.

Figur 1

schematisch eine Darstellung zur Erläuterung des Wirkprinzips des Beschleifens von Schienenoberflächen mittels frei rotierender, nicht aktiv angetriebener rotationssymmetrischer Schleifkörper mit gegenüber der Schienenlängsrichtung in einem spitzen Winkel eingestellter Rotationsachse;

Figur 2

schematisch die Darstellung eines Schleifaggregates einer Vorrichtung zur Schleifbearbeitung der Oberfläche von im Gleis verlegten Schienen, welche mit dem in Fig. 1 dargestellten Schleifprinzip arbeitet, mit einem an dem Schleifaggregat angeordneten Haltebalken und einer daran angeordneten Schleifkörperreihe;

Figur 3

in einer Darstellung relativ zur Schiene ein Abschirmelement einer erfindungsgemäßen Vorrichtung in zwei unterschiedlichen Positionen, einmal angehoben (in durchgezogenen Linien) und einmal abgesenkt in Richtung der Schien (in gestrichelten Linien) sowie einen Doppelpfeil zur Veranschaulichung der möglichen Anstell- bzw. Abhebbewegungen;

Figur 4

in einer Querschnittsansicht schematisch einen über die Schiene abrollenden und dabei eine Schleifbearbeitung ausführenden Umfangsschleifkörper der der erfindungsgemäßen Vorrichtung mit zu beidem Seiten der Schiene angeordneten und in einer abgesenkte Gebrauchsstellung befindlichen Abschirmelementen zum Abfangen und Zurückhalten von beim Schleifen entstehenden Abriebpartikeln sowie sich an die Abschirmelemente anschließenden Absaugkanälen.

Further advantages and features of the invention will become apparent from the following description of an embodiment with reference to the accompanying figures. Showing:

FIG. 1

schematically a representation for explaining the operating principle of the grinding of rail surfaces by means of freely rotating, not actively driven rotationally symmetric grinding body with respect to the rail longitudinal direction set at an acute angle rotation axis;

FIG. 2

schematically the representation of a grinding unit of a device for grinding the surface of rails laid in the track, which with the in Fig. 1 illustrated grinding principle works, with a arranged on the grinding aggregate holding beam and an abrasive body row arranged thereon;

FIG. 3

in a representation relative to the rail, a shielding element of a device according to the invention in two different positions, once raised (in solid lines) and once lowered in the direction of the rails (in dashed lines) and a double arrow to illustrate the possible Anstell- or lift-off movements;

FIG. 4

in a cross-sectional view schematically a rolling over the rail and while grinding perform exporting peripheral grinding of the device according to the invention arranged on both sides of the rail and located in a lowered position of use shielding for intercepting and retaining abrasion resulting during grinding abrasion and subsequent to the shielding Absaugkanälen.

In the figures, the grinding principle used when using the device according to the invention and the device-side implementations and features essential to the invention are illustrated schematically. Based on these figures, the invention will be described below in a possible embodiment or in possible embodiments. The figures are mere sketches, which are neither true to scale nor intended to serve as complete construction drawings.

FIG. 1 shows again in a schematic representation of the action or function of the grinding of a track laid in the track S with an abrasive body 1, which is mounted freely rotatable about a grinding wheel axis 2 and at an acute angle α to the rail longitudinal direction SL in a direction F is moved , By a combination of this locomotion in the direction of travel F and the orientation of the grinding body axis of rotation 2 at an acute angle α to the rail longitudinal direction SL (which is parallel to the direction of travel F), the grinding wheel 1, which is rotationally symmetrical to the grinding wheel rotation axis 2, is set into a rotation at the same time to a relative speed between an abrasive body surface 3 and a rail surface SO of the rail S leads. This relative movement in turn leads to a Abschleifwirkung, which manifests itself in a grinding in a ground area SB of the rail surface SO. As a result of this abrasion, previously existing defects such as grooves, corrugations or microcracks are removed in the ground area SB, the rail surface SO is ground flat.

In the FIG. 1 is for better orientation and the rail foot SF designated, which is arranged anchored in the installed position in the track in a vertical lowermost position on the thresholds.

In the FIG. 1 designated and described mode of action is the one mentioned in the beginning EP 0 708 205 A1 is described. In FIG. 2 is shown in a highly schematic representation of a schematic diagram of a grinding unit 4, which is part of a device for grinding of rails laid in the track during a crossing and after the above with reference to FIG. 1 described operating principle works. This grinding unit 4 has on a chassis rail wheels 5, with which it travels over the rail S to be ground. Such a grinding unit 4 is - even in the prior art - typically a part of a whole grinding train, usually a plurality of such grinding units, for example, four, for grinding both parallel laid in the track rails S. At the grinding unit 4, an abrasive body frame 6 is arranged , The grinder frame 6 can be lifted in the vertical direction of the rail S or lowered to this and pressed against the rail surface SO. The latter position is in the Fig. 2 shown. For the purpose of vertical displacement of the grinding wheel frame 6 lifting and pressure cylinder 7 are present, which not only cause raising and lowering of the grinding wheel frame 6, but also exert a pressing force on the grinding wheel frame 6 in the direction of the rail surface SO of the rail S. The grinding wheel frame 6 includes an abrasive body assembly 8 having abrasive bodies 1 lined up therein, which, as in FIG FIG. 2 can be seen, are arranged in different orientation at an acute angle to the orientation of the rail S.

In FIG. 3 schematically is a arranged in the device according to the invention shielding 9 with an abrasive assembly formed here of two groups of Umfangsschleifkörpern 1 (shown in dashed lines). The shielding elements, of which in FIG. 3 only one, in FIG. 4 but two are shown contain at least on an approach of abrasion particles resulting from grinding AP (see FIG. 4 ) exposed surface a laminate material from a reinforced with mineral particles (these may be mineral fibers, but also mineral particles of another form) reinforced resin or are formed at least on such a surface of such a material. In a preferred embodiment, the shielding elements 9 as a whole consist of such a mineral-particle-reinforced synthetic resin laminate. A material used according to the invention has proven to be on the one hand sufficiently resistant to heat and abrasion in order to counteract the impacting sparks of the abrasive particles AP (cf. FIG. 4 ) withstand a sufficient amount of time. On the other hand, this material is also without disturbing influence on working with magnetic effects sensors in the track area, such as Radzähler.

In the preferred embodiment, the laminate material is formed from mica particle reinforced silicone resin. In particular, a laminate material made of silicone resin impregnated mica paper under high pressure and temperature has been found suitable and has been used for the embodiments. In this case, this has been proven by the company AGK High Performance Materials GmbH of Dortmund, Germany, offered under the brand name "K-Therm ^® AS M" on the market laminate material of this style to be particularly common and was used in the preferred embodiments, particularly preferred in this special one Material with the designation "K-Therm ^® AS 600 M".

The plate-shaped material was formed to the shielding elements 9, which were also substantially plate-shaped with folds 13 (see. FIG. 4 ) at their edges in operation in a lower region of the head of the rail S adjacent. The material thickness of these plates was in the embodiment between 5 and 20 mm, with particularly good success between 6 and 15 mm. In FIG. 3 the fact that the shielding elements 9 (here only one of the shielding elements 9 guided on both sides of the rail and arranged in the device) can be displaced in their respective height position can be seen in particular. This is indicated by the double arrow D, wherein in solid lines the shielding element 9 in an obliquely upward outside (away from the rail), shown in dashed lines in a lowered position (the working position).

This figure also shows that the shielding elements 9 may in particular have bearing edges, here shown at 10, in each case a bearing edge 10 at each front end, with which these on the device fixedly arranged storage or stop structures, here stops 11, in the lowered state (The position shown in dashed lines) can be stored or loaded so as to obtain a defined and stable position of the shielding element 9 in the lowered position, so that the area around the rail S can be enclosed as closely reproducible and tight sealing of the shielding elements 9 so as to capture as much as possible the entire particle abrasion and to prevent the particles from escaping into the environment. The stops 11 are above the level of the rail S on the frame of the grinding frame (not shown here) fixed and thus remain in operation relative to the rail top, ie in the vertical direction, stationary. On these stops 11, the shielding element 9 is lowered in the lowered state with its support edges 10 in a defined position. As a result, on the one hand, a precise alignment of the shielding element 9 in the lowered state is achieved, but on the other hand also a certain stabilization of this element and also a fixing thereof in the lowered state.

In particular, as in FIG. 4 shown in the upper part of the shielding elements 9, a connection 12 for a suction (illustrated by the arrows P) are located so that the retained by the shielding elements 9 in this area sucked particles and collected in a collecting device on the device for grinding the rails and collected can for the purpose of proper disposal.

It can be seen in the Figures 3 and 4 also that the shielding elements 9 are formed trough-like with starting from the rail S obliquely widening surfaces. By this configuration, particles impinging on the shielding elements 9 are directed away from the rail head into an upper section, where the suction arranged there connects to port 12 and traps the particles.

LIST OF REFERENCE NUMBERS

1

Peripheral grinding body

2

Grinding wheel rotational axis

3

Grinding lateral surface

4

sanding unit

5

A rail

6

Grinding frame

7

Lifting and impression cylinder

8th

Abrasive arrangement

9

shielding

10

supporting edge

11

attack

12

connection

13

fold

AP

Abrieppartikel

D

double arrow

F

direction of travel

P

arrow

S

rail

SB

cut range

SF

rail

SL

Rail longitudinal direction

SO

rail surface

α

angle

Claims (10)

1. A device for grinding rails (S) on the track during a passage with

   a) a rolling chassis and wheel tyres arranged thereon to travel on the rails to be ground (S),

   b) a grinding body frame (6) driven by the rolling chassis,

   c) grinding bodies (1) held in the grinding body frame (6), which can be offset in rotation around the rotational axis (2) of the grinding body, and which can be mounted against the surface (SO) of a rail (S) to be ground

   d) as well as at least one shielding element (9) provided laterally beside the grinding bodies (1), in the running direction of the wheel tyres, to catch and retain abrasion particles (AP) and sparks generated during the grinding process,

   characterised in that
   the shielding element (9) always contains a laminated material made of a synthetic resin reinforced ith mineral particles, on its surface which is exposed to flying abrasion particles (AP) and sparks.
2. The device according to claim 1, characterised in that the shielding element (9) consists as a whole of the laminated material made of the synthetic resin reinforced with mineral particles.
3. The device according to any of the preceding claims, characterised in that the laminated material consists of silicone resin reinforced with mica particles.
4. The device according to any of the preceding claims, characterised in that the shielding element (9) is mainly plate-shaped.
5. The device according to claim 4, characterised in that the shielding element (9) has a thickness of 5 to 20 mm, in particular 6 to 15 mm.
6. The device according to any of the preceding claims, characterised in that, seen in the running direction of the wheel tyres, laterally beside the grinding bodies (1) on both sides, shielding elements (9) are provided to catch and retain abrasion particles (AP) and sparks generated during the grinding process, which shielding elements both contain the laminated material made of a synthetic resin reinforced ith mineral particles, on its surface which is exposed to flying abrasion particles (AP) and sparks.
7. The device according to claim 6, characterised in that the shielding elements (9) exhibit, on their lower sections facing the rail (S) when in operation, an angulation (13) facing respectively the opposite shielding element (9) and form together a protection in the form of a trough expanding upwards from the lower sections.
8. The device according to any of the preceding claims, characterised in that, in the region of said at least one shielding element (9), an extraction device is provided to extract the abrasion particles (AP) and sparks caught and retained by the shielding element (9).
9. The device according to any of the preceding claims, characterised by means for lifting anf lowering said at least one shielding element (9).
10. The device according to any of the preceding claims, characterised in that the grinding bodies (1) are peripheral grinding bodies and mounted to rotate freely without a driving system, on the grinding body frame (6) with its rotation axes (2) under an acute angle (a) with respect to a longitudinal direction of the grinding body chassis (6), a direction which corresponds substantially to the running direction of the wheel tyres.

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