EP2390415B1 - Grindstone assembly with minimal resulting momentum and power - Google Patents

Description

The present invention relates to a device for machining the running surfaces of rails by peripheral grinding with at least one adjustable to the running surface of the rail and movable along the rail grinding frame, which has at least three each freely rotatably mounted grinding wheels for peripheral grinding with an acute angle to the rail longitudinal direction enclosing axis of rotation ,

It is known to free laid rails in the track by grinding of near-surface defects and / or reprofiling. It is known to use for rotation active driven peripheral grinding wheels or cup wheels, wherein the driven peripheral disks come also to Include differently directed acute angle to the rail longitudinal direction used and can be individually lifted off the rail. Examples of this are in the interrelated references EP 0344390 A1 and EP 0315704 A1 disclosed. Another example of a device for grinding rails with driven grinding wheels is in EP 0843043 A1 disclosed.

A recent practice, the new grinding process is grinding with passively driven grinding wheels, such as in a process with the features of the preamble of claim 1 revealing EP 0 708 205 A1 is described. In this case, rotatably mounted on an axis (rotation axis) peripheral grinding are pulled under a twisted about the vertical axis angle of usually 40 ° - 60 ° without its own drive on the rail, they begin to rotate. Due to the inclination takes place between the peripheral surface of the grinding wheel and the rail surface, a relative movement, which triggers a decision of the rail with increasing towing speed. The rail grinding usually takes place at 80 km / h, the power for the drive of the grinding body comes from the traction power alone.

The grinding wheels are arranged in the frame of this grinding process device in which they can be raised or lowered and pressed. They are usually not arranged individually but in groups one behind the other, so that such a group is moved together. This is for example in the Fig. 5 the already mentioned EP 0 708 205 A1 shown. There are shown in the apparatus two racks, each with five in the same way inclined grinding wheels.

Depending on the size of the contact pressure, the abrasion of the individual grinding body on the rail but also the reaction forces vary: first, a resistance force Fw in opposite direction of travel, which is compensated by the propulsive force of the machine, on the other hand arises by the inclination also a transverse force F _o , which wants to drive the grinding body laterally from the rail and which can be compensated by a corresponding guide, which would have to be supported on the rail. The magnitude of this transverse force increases proportionally according to the number of abrasive bodies in the mentioned group. Therefore, in a like in Fig. 5 of the EP 0 708 205 A1 shown arrangement, the lateral forces add up to substantial orders of magnitude. Accordingly stable and stiff, therefore, the guide would have to be designed to both statically absorb the lateral forces and prevent derailment, as well as dynamically periodic running and retraction due to elasticities in the structure or track changes or other disturbances with the result to avoid a non-uniform microsection and in the worst case a wavy rail surface.

From the EP 1 460 176 A1 It is known to arrange in a frame grinding wheels for grinding of different sections of the rail surface.

Based on this prior art, it is an object of the invention to improve a known device for machining the running surfaces of rails by peripheral grinding of the type mentioned, ie with passively driven grinding wheels to the effect that they provided with less material and thus cheaper to produce grinding racks can be while maintaining an optimal microsection even at high speed and processing speeds of the device.

This object is achieved by a device for machining the running surfaces of rails by peripheral grinding with the features of claim 1. Advantageous developments of a device according to the invention are specified in the dependent subclaims 2 to 8.

The basic idea on which the present invention is based is that, unlike the arrangement of the abrasive bodies in a grinding rack, as is known for devices with passively driven grinding wheels in the prior art, for example in the FIG. 5 of the EP 0 708 205 A1 shown to make the grinding in a frame not all in a same direction with its axis of rotation relative to the longitudinal direction of the rail to be machined, but here to work with angles of different sign and thus to obtain at the different stones transverse forces in different directions transverse to the Rail can point. In this way, with a suitable arrangement of the grinding wheels, which the person skilled in the art can easily determine, it can be achieved that the transverse forces occurring at the individual grinding bodies compensate each other, ie that the vector sum of the individual transverse forces acting on the grinding bodies is substantially zero. Thus, the occurrence of a resultant lateral force on the buff is prevented altogether at first.

According to the invention an even number of abrasive bodies is arranged in the grinding rack, and there are two abrasive bodies of the same type arranged with its axis of rotation at an acute angle of the same amount but different sign to the rail longitudinal direction. This type of design of the device provides a simplification insofar as grinding wheels of the same type can be used in pairs, which facilitates design considerations in terms of simplification and standardization.

An essential part of the invention is then also that a resulting torque around the vertical axis avoided, so the sum of all acting on the individual grinding wheels torques is also zero. Such a non-zero torque, which may also be referred to as a yaw moment, causes the arrangement of the grinding frame to yaw, ie to rotate about its vertical axis.

Depending on the arrangement of the grinding bodies along the grinding frame, a torque is set due to the distribution of forces relative to a pivot point, which seeks to effect a rotation of the grinding frame about a perpendicular to the longitudinal direction of the grinding frame, passing through the pivot axis of rotation. Another condition for an inventive arrangement of the grinding in the grinding rack is now that they are arranged distributed in their distance from such a fulcrum that on both sides of this fulcrum an equal in magnitude, but in the opposite sign torque is obtained. In other words, the sum of the products of the distance of a point of force application to a grinding wheel and the force applied to this grinding wheel is equal to zero for all grinding wheels.

• Bei Betrachtung der Schleifkörper und der Schiene von oben, liegt dann ein "positiver" spitzer Winkel vor, wenn die Rotationsachse des Schleifkörpers gegenüber der Schienen-Längsachse nach entgegen dem Uhrzeigersinn gerichteter Drehung aus einer Parallelstellung einen spitzen Winkel bildet.

In order to meet these conditions with an even number of grinding wheels and identical acute angles of the same sign, it takes at least four grinding wheels. With the sign of the acute angle, an orientation of the abrasive bodies is likewise expressed here. Looking at the arrangement of the grinding wheels in a supervision, as they their Rotational axes lie to a longitudinally extending rail, so can be set up for a designation according to the invention of the sign of the acute angle the following definition:

• When looking at the grinding wheels and the rail from above, there is a "positive" acute angle when the axis of rotation of the grinding wheel forms an acute angle with respect to the longitudinal axis of the rail in the counterclockwise direction from a parallel position.

If such an abrasive body, which is employed at a positive acute angle, is moved over the rail in the rail longitudinal direction and unrolled, then it has a tendency to run off to the right in the direction of movement from the rail.

A negative acute angle is correspondingly at an angle given by the same consideration by an acute angle in the clockwise direction, the relevant grinding body then wants to run to the left of the rail.

It now appears clear that, in this positive angle positive angle during movement of the grinding body on the rail in the direction of travel directed to the right of the rail directed transverse force occurs, with an orientation of the grinding wheel with a negative acute angle between the rail longitudinal direction and axis of rotation in the opposite direction, so seen in the direction of travel to the left of the rail directed transverse force acts. Due to the fact that transverse forces to both directions of the rail are achieved by the inventive alignment of the grinding body under the sign of the corresponding arrangement at least divergent acute angles, these can be adjusted by selecting the distribution of arranged with different angles of attack grinding so that on neutralize any transverse forces acting on all grinding bodies during a vectorial addition, ie they are zero. This can be achieved, for example, by providing in the center a pair of abrasive bodies, for example arranged at a positive acute angle, which applies a double transverse force, such as two further abrasive bodies arranged in front of and behind this pair of abrasive bodies with negative ones acute angle to the rail longitudinal direction set rotation axis. When these abrasive bodies are respectively arranged equidistant from the central abrasive bodies so as to apply a transverse load of half the horizontal force in operation in the opposite direction to the lateral force of the central abrasive bodies during operation, the condition of both force and torque freedom is satisfied.

In such a fitting of the grinding rack, correspondingly much less stress on the frame itself, which thus can be built material-saving and cost-effective and at the same time due to the absence of the occurrence of resulting lateral forces or torques are performed safer along the rail and thus produce a better grinding pattern can. The possibility of forming the grinding racks filigree and with less use of materials, also allows a more compact overall design, making the device per se can be made more compact, material-saving and lighter. Also, it is in principle possible to achieve with such a device higher driving and processing speeds, which were not possible with arrangements, as known from the prior art, since the lateral forces increase sharply at higher speeds and even increased from a limit speed of the executed grinding racks can not be recorded.

Even if in principle, in particular with increasing number of grinding wheels, a plurality of arrangements and configurations is possible, which can be designed according to the invention with essentially zero resulting transverse force and substantially without resulting torque, but from a constructional point of view are the simple variants to prefer such arrangements.

A simplification is obtained with an embodiment of the device according to the features of claim 2. Accordingly, the apparatus comprises four grinding wheels or grinding wheels in a number of a multiple of four, which are arranged in the grinding rack along an imaginary line one behind the other. The arrangement is designed so that it starts from one on The center located on both sides of the same center has the same number of grinding wheels. The abrasive bodies are arranged so that in each case an abrasive body of the same type is arranged to both directions of the center at the same distance, that the axes of rotation of the same distance to the center of the abrasive body with the rail longitudinal direction include the same acute angle. In other words, symmetrically distributed around the center in the arrangement of the abrasive body in each case a pair of grinding wheels make out, which is located at the same distance from the center on the imaginary line on both sides of the center, each with an abrasive body. These grinding wheels are provided with the same orientation, ie acute angles of the same magnitude and sign. The center in such an arrangement simultaneously forms the fulcrum, so that due to the same orientation of the grinding bodies, which are arranged at the same distance from the center, the requirement of neutralizing torques is given. Together with the above condition then results in a substantially torque and force-free arrangement of the abrasive body with a comparatively simple structural design.

The structure is even further simplified if, as provided in claim 3, all the grinding bodies with their axes of rotation to the rail longitudinal direction include an angle of equal magnitude, in particular in the range of 40 ° to 60 °, but with different signs.

In order to achieve a particularly compact arrangement of the grinding bodies in the grinding rack, they can be combined with advantages as provided in claim 4 in groups. This summary is carried out so that such abrasive bodies, which include a positive acute angle with their axes of rotation to the rail longitudinal direction, each to a side and to the one beyond the center located group are summarized and the same thing is done with such abrasive bodies, which include a negative acute angle with its axis of rotation to the rail longitudinal direction.

The device is particularly simple and compact to build, if all the abrasive bodies in the grinding rack are of the same type. In particular, this results in a particularly simple determination or estimation of the occurring shear forces, since they are the same size in grinding wheels of the same type and magnitude equal selected angle of attack. Thus, then only the number of arranged under positive and negative acute angle abrasive must be compensated and provided for a corresponding torque compensation.

For a fully circumferential machining of the rail surface, it is necessary that not only the upper slightly curved tread on the rail head, but in particular the more curved inner edge facing in the track of the opposite rail and the outer edge located on the other of the rail head, ie the areas in where the upper tread of the rail head merges into the side areas. In this case, it is particularly appropriate for the grinding bodies to be arranged in the grinding frame in such a way that grinding wheels which enclose with their axis of rotation to the rail longitudinal direction an acute angle of a first sign (for example positive) for the processing of the one edge, eg. For example, the outer edge of the rail may be used, whereas those which have the opposite sign of the acute angle between their axis of rotation and the rail longitudinal direction (eg, a negative acute angle) may be used for machining the other edge (e.g. Outer edge) are arranged. In this arrangement, the grinding bodies with the centers of their axes of rotation may not be exactly aligned, are within the meaning of the invention, in particular in the sense of the above-described arrangement according to claim 3 and all claims back referring nevertheless on a line. The slight offset of the centers of the axes of rotation of a thought drawn line to the right or left here changes nothing.

Advantageously, the device may comprise a self-propelled vehicle with a chassis on which the at least one grinding rack is arranged. Of course, variants are also conceivable in which grinding frames, e.g. are arranged on the chassis of a not self-propelled, towed vehicle.

In a device according to the invention at least two grinding racks are arranged so that at least one grinding rack is provided for each of the rails running in a track. Of course, it is also possible for the processing of a rail in a row two or even more grinding racks with abrasive bodies to arrange, for example, to obtain a higher material removal or to order with different Schleifkörperanordnungen in the individual Grinding racks to grind different area of the rail surface. This can be done, for example, with grinding bodies in a first grinding rack, which grind only the driving surface. With grinding wheels in another grinding rack, the grinding of one or both edges of the rail head (the inner edge or outer edge) can be performed.

Figur 1

eine der Figur 5 der EP 07 082 005 A1 entsprechende Prinzipdarstellung einer gattungsgemäßen Vorrichtung zum Bearbeiten der Laufflächen von Schienen nach dem Stand der Technik;

Figur 2

eine schematische Darstellung der Wirkweise eines in einer erfindungsgemäßen Vorrichtung angeordneten Schleifkörpers mit dem beim Betrieb desselben auftretenden Kräften in der Draufsicht;

Figur 3

zur weiteren Erläuterung eine Darstellung mit zwei unter spitzen Winkeln gleichen Betrages jedoch unterschiedlichen Vorzeichens mit ihrer Rotationsachse zu der Schienenlängsrichtung angeordneten Schleifkörpern zur Erläuterung des Entstehens eines auf die Aufhängung dieser Schleifkörper in Form des Schleifgestells wirkenden Drehmomentes;

Figur 4

schematisch ein erstes Ausführungsbeispiel für eine erfindungsgemäße Anordnung von vier Schleifkörpern in einem Schleifgestell mit zu einer resultierenden Querkraft von null sich addierenden auftretenden Querkräften und ohne resultierendes Drehmoment;

Figur 5

ein zweites Ausführungsbeispiel für eine erfindungsgemäße Anordnung von Schleifkörpern in einem Schleifgestell in schematischer Darstellung mit acht Schleifkörpern und wiederum ohne resultierende Querkraft und ohne resultierendes Drehmoment;

Figur 6

in einer weiteren stark schematischen Darstellung eine dritte Ausführungsform einer erfindungsgemäß Anordnung von Schleifkörpern in einem Schleifgestell.

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

FIG. 1

one of the FIG. 5 of the EP 07 082 005 A1 corresponding schematic diagram of a generic device for machining the running surfaces of rails according to the prior art;

FIG. 2

a schematic representation of the mode of action of an arranged in a device according to the invention abrasive body with the same occurring during operation forces in plan view;

FIG. 3

for further explanation, a representation with two at acute angles same amount but different sign with its axis of rotation to the rail longitudinal direction arranged grinding bodies to explain the occurrence of acting on the suspension of these grinding wheels in the form of the grinding rack torque;

FIG. 4

schematically a first embodiment of an inventive arrangement of four grinding wheels in a grinding rack with a resultant transverse force of zero, the resulting lateral forces and without resulting torque;

FIG. 5

a second embodiment of an inventive arrangement of abrasive bodies in a grinding rack in a schematic representation with eight grinding wheels and again without resulting lateral force and without resulting torque;

FIG. 6

in a further highly schematic representation of a third embodiment of an inventive arrangement of abrasive bodies in a grinding rack.

In FIG. 1 is initially in a representation according to the FIG. 5 of the EP 07 082 005 A1 a section of a device for machining the running surfaces of rails by peripheral grinding by means of oblique position due to the resulting frictional force driven during driving abrasive body shown. For a more detailed explanation of the operation of this method, which is also the embodiment of the invention is based on the EP 07 082 005 A1 and the presentation given there, which - insofar as nothing else is described below - also applies to the inventive development validity.

In this known, in FIG. 1 The prior art apparatus shown are arranged on a chassis 1, which is connected to wheels 2, which roll along a rail 3, a total of two grinding racks 4. In these grinding racks 4 5 rotating grinding wheels 6 are arranged freely rotatable on axes of rotation, here five grinding wheels per grinding rack 4. The arrangement of the grinding wheels 6 is such that the rotational axes 5 form an acute angle to the longitudinal extent of the rail 3. The grinding racks 4 are arranged vertically adjustable on the chassis 1 of the device, so that they can be lowered and placed on the rail 3, so that as shown for the left in the figure grinding frame 4, the grinding wheel 6 with a peripheral surface 7 on a tread 8 of the rail 3 abut. In the figure to the right, the sanding frame 4 is shown in a raised state. In the lowered and employed to the rail 3 state, the grinding frame 4 is applied with suitable, unspecified means here, directed against the tread 8 pressing force to press the grinding wheel 6 against the tread 8 of the rail 3. Now, when the device moves over the rail 3 at a speed v along the direction shown in the associated arrow, a friction of the grinding wheels results due to the friction 6, which leads to a grinding action and abrasive machining of the tread 8 of the rail 3.

This principle is once again in FIG. 2 illustrated in a schematic representation of a single abrasive body 6, wherein the various forces occurring are shown here.

In this FIG. 2 an abrasive body 6 is shown, which encloses with its axis of rotation 5 an acute angle of the amount α to the rail longitudinal direction L, said angle α lies in an imaginary quadrant seen in the direction of travel speed v to the right of the rail 3 and before an intersection point S. the axis of rotation 5 with the rail longitudinal direction L is located. For further consideration and comparison of the different angles of attack, such an angle should be referred to here as a negative angle -α.

Due to the inclination of the fixed in the grinding frame 4 rotation axis 5 of the grinding wheel 6 to the rail longitudinal direction L results when the grinding wheel 6 is pressed against the running surface 8 of the rail 3 and moved in the direction shown in the illustration at a speed v, a Frictional force that drives the grinding wheel 6 to rotate, here shown with the arrow labeled "n". The remaining force can be divided into a lying parallel to the rail longitudinal direction L force Fw, which is opposite to the propulsion speed v and is referred to as a resistance force, and in a transverse force Fa directed at the corresponding orientation of the grinding wheel 6, as in FIG. 2 is shown, is directed to the left side of the rail 3 seen in the direction of travel. This transverse force F _Q as well as the resistance force Fw must be absorbed by the grinding frame 4, to which these forces are transmitted via the rotation axis 5 of the grinding wheel 6.

It will now be readily apparent that with an arrangement of several abrasive bodies in the same orientation of an acute angle -α, as in the prior art (cf. FIG. 1 ) happens, the transverse forces F _Q occurring for each grinding _{wheel 6} add up to a resulting transverse force F _Qres , the significant Can accept values. Since the magnitude of the lateral force Fa depends not only on the amount of the angle α and the geometry of the grinding wheel 6, but also on the contact pressure and the driving _speed v, it can be seen that the faster the resulting lateral force F _Qres Driving and processing speed of the device is. This resulting transverse force F _Qres must be absorbed by the grinding _frame 4, to which the latter is very solid and with high material use and expense to train.

This requirement should now be counteracted.

In FIG. 3 is schematically shown a preliminary stage of the consideration on the way to an arrangement according to the invention. Here, two grinding wheels 6 of the same design are arranged, which are aligned with their axes of rotation 5 under equal acute angles α to the rail longitudinal direction L, wherein the acute angle α but are seen in different quadrants in the direction of the propulsion speed v. While for the abrasive body shown on the left in the figure, an orientation with a negative angle -α as in FIG. 2 is shown, the acute angle for the abrasive body shown in the figure on the right in a direction of speed v behind the intersection S between the axis of rotation 5 and the rail longitudinal direction L located quadrant right of the rail 3 and is here correspondingly as a positive sharpener + α defined. This arrangement in terms of absolute same, but signally different acute angles + α and -α causes the lateral force Fa for the left in the figure shown grinding wheel 6 in the direction of speed v is directed away from the rail 3 to the left, while on the transverse force Fa, which is shown in the figure on the right, extends to the right side of the rail 3. Due to the magnitude same size of the acute angle α for the same type of the grindstone 6 is - when, as in practice used the same pressure on both grinding bodies 6 in the direction of the tread 8 - the amount of the two transverse forces F _Q the same, so that these lateral forces Fa in the case of vectorial addition, cancel altogether and the resulting lateral force F _{Qres becomes} zero to the grinding _rack . In this arrangement, however, arises due to the different Assuming attacking, pointing in different directions transverse forces Fa a non-zero torque M, as indicated in the figure. This torque M acts on the grinding frame 4 and leads to further problems in the construction.

The further considerations on the way to an inventive arrangement of grinding wheels 6 and corresponding design of the devices are now a repeal of the resulting torque M to create. An arrangement which also satisfies this requirement is shown in a first example in FIG FIG. 4 shown. Here now a total of four grinding wheels 6 of the same design are arranged, which enclose α with their axes of rotation 5 amount equal to an angle. Of the again arranged in an even number of abrasive bodies 6 each half with a positive acute angle + α between the respective axis of rotation 5 and the rail longitudinal axis 11 and a negative acute angle -α between these directions in a grinding frame, not shown here, is arranged. Thus occur at the same contact pressure on the grinding wheels 6, as it is used in practice, transverse forces Fa same amount, but in the above-discussed different directions in each case in equal numbers, so that the transverse forces Fa turn to a resulting transverse force F _Qres vectorially add from zero. The grinding wheels 6 have in this arrangement to each other (more precisely in the distance of the intersections S of the axes of rotation 5 with the rail longitudinal direction L adjacent grinding wheels 6) each at an equal distance and are distributed so that right and left of an imaginary center P of the arrangement in each case in the same Distance to this center P each one grinding wheel 6 with a positive acute angle + α or one grinding wheel 6 with a negative acute angle -α is present. In this arrangement, the torque generated by the force acting on the individual grinding wheel 6 each transverse forces Fa torques and give a total of a torque of M = 0. In this arrangement according to the invention, the grinding wheels 6 can be accommodated and arranged in a grinding rack 4, without a resulting lateral force F _Qres occurs and without a torque M acts on the grinding _rack . The grinding rack can be carried out accordingly with less structural complexity are higher working speeds v allows, and the risk of dodging or tilting of the arrangement of the grinding wheel 6 and this holding in the arrangement Abrasive 4 with the negative consequences for the grinding pattern and the possible risk of an abrasive breakage are avoided.

In FIG. 5 is shown in a further schematic representation of a way to provide more abrasive assemblies with more than four, namely a multiple of four grinding wheels 6. In this arrangement, grinding wheels 6 of the same type are arranged under equal acute angles α between the rail longitudinal direction L and their axes of rotation. In this case, a first group of grinding wheels 6 is provided with their above-described distances to a center P on both sides symmetrically in the center of the arrangement, this group has grinding wheels 6 in a number 2n, where n is a natural number. In the direction of the rail longitudinal direction L in front of and behind this middle group, a group of grinding wheels 6 are arranged in an alignment at an acute angle with signs different from the acute angles of the first group, each in a number n, where n is a natural number. The positions of these grinding wheels 6 are distributed symmetrically to the center point P. Here, too, as can easily be seen in the illustration of the figure, a resulting transverse force F _Qres of zero and a likewise omitted resulting torque M, if this arrangement is summarized in a grinding rack. Through the front and rear groups of the grinding wheels 6, a force of n * F _{Q is} exerted on the grinding rack to one direction of the rail 3, the central group exerts on the grinding rack a total force of 2n * F _Q. Due to the symmetrical distribution around the center P results on both sides of a moment equilibrium, so that the resulting torque M is zero.

In FIG. 6 is in an even more schematic representation (here are only the axes of rotation 5 of the abrasive 6 shown) another possible arrangement of abrasive in a grinding rack shown, in which case abrasive of the same type with the same amount acute angles α with different Signs are arranged in a row one behind the other so that the resulting lateral force F _{Qres is} also zero as the torque M. Here at distance A to a pivot point D respectively before and behind this pivot point D seen in the rail _{longitudinal direction} L each arranged an abrasive body, the other Abrasive bodies are then distributed at the same distance A from this first grinding body or the other grinding bodies in the rail longitudinal direction L in front of and behind the pivot point D. In this arrangement, without the in the FIGS. 4 and 5 shown symmetry by skillful choice of the distribution of the positive and negative acute angles, the cancellation of the occurring lateral forces Fa to a resultant transverse force F _Qres of zero and the freedom of a resulting torque M achieved.

Due to the foregoing description of the embodiments, the meaning and utility of the invention have again become clear.

LIST OF REFERENCE NUMBERS

1

chassis

2

Wheel

3

rail

4

sanding frame

5

axis of rotation

6

abrasives

7

peripheral surface

8th

tread

A

distance

D

pivot point

F _Q

lateral force

F _Qres

resulting lateral force

fw

resistance

L

Rail longitudinal direction

M

torque

n

rotation

P

Focus

S

intersection

V

speed

+ α

positive acute angle

-α

negative acute angle

Claims (8)

1. A device for machining the running surfaces (8) of rails (3) by peripheral grinding with at least one grinding frame (4) which is adjustable at the running surface (8) of the rail and which is mobile along the rail (3), which includes at least four grinding bodies (6) mounted rotatably and freely about their respective rotation axis (5) for peripheral grinding, whereas the grinding frame (4) is arranged in such a way and the grinding bodies are mounted in such a way that with a grinding frame (4) adjusted for machining the running surfaces (8)the rotation axes (5) form an acute angle (α) with respect to a rail longitudinal direction, , characterised in that the grinding frame (4) comprises an even number of grinding bodies (6) whereas grinding bodies of the same design are arranged with their rotation axes in the grinding frame (4) in such a way that, with a grinding frame mounted on a rail (3) for machining the running surfaces (8), the rotation axes (5) of a first group of grinding bodies (6), containing numerically half the grinding bodies (6), form respectively a first acute angle (+α) with respect to the rail longitudinal direction (L), and the rotation axes (5) of a second group of grinding bodies (6), containing numerically half the grinding bodies (6), form respectively a second acute angle (-α) deviating in its prefix from the first acute angle (+α) with respect to the rail longitudinal direction (L), whereas all the first and second acute angles (+α, - α) are respectively equal, and whereas the configuration of the grinding bodies (6) is selected in such a way that a resulting torque (M), acting on the grinding frame (4) perpendicularly to the approach direction, is substantially equal to zero.
2. The device according to claim 1, characterised in that it entails four or a multiple of four grinding bodies (6), which are arranged in the grinding frame (4) along an imaginary line, and that starting from a centre (P) situated on the line, the same number of grinding bodies (6) is respectively provided on both sides of said centre in such a way that a grinding body of the same design is arranged respectively at the same distance with respect to both directions of the centre (P) so that the rotational axes of these grinding bodies (6) having the same distance with respect to the centre (P) form the same acute angle (+a, -a) with respect to the rail longitudinal direction.
3. The device according to one of the preceding claims, characterised in that all the grinding bodies (6) with their rotation axes (5) form an acute angle (α) of the same value, in the range between 40° and 60°, with respect to the rail longitudinal direction, with different prefixes.
4. The device according to claims 2 and 3, characterised in that the grinding bodies (6) which form with their rotation axes (5) a positive angle (+α) with respect to the rail longitudinal direction (L), and that the grinding bodies (6), which form with their rotation axes (5) a negative angle (-α) with respect to the rail longitudinal direction (L), are respectively united into groups of neighbouring grinding bodies (6) in such a way that there is a group of grinding bodies (6) of both orientations on both sides of the centre (P).
5. The device according to one of the preceding claims, characterised in that all the grinding bodies (6) in the grinding frame (4) have the same design.
6. The device according to one of the preceding claims, characterised in that the grinding bodies (6) are arranged so that the grinding bodies (6) whose rotation axes (5) form an acute angle (+α) with respect to the rail longitudinal direction (L) with a first prefix are oriented for meshing into an inner edge of the running surface to be machined (8) and the grinding bodies (6), whose rotation axes (5) form an acute angle (-α) with respect to the rail longitudinal direction (L) with a second prefix deviating from the first prefix, are oriented for meshing into an outer edge of the running surface to be machined (8).
7. The device according to one of the preceding claims, characterised in that it comprises a self-propelled vehicle with a rolling chassis (1) on which at least one grinding frame (4) is provided.
8. The device according to one of the preceding claims, characterised in that it contains at least two grinding frames (4) with grinding bodies (6) arranged and oriented accordingly, whereas at least one grinding frame (4) for the grinding operation of each of both rails (3) running on a track is provided.

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