GB1576193A

GB1576193A - Process and a rail grinding vehicle for smoothing out irregularities in the surface of railheads

Info

Publication number: GB1576193A
Application number: GB6879/78A
Authority: GB
Original assignee: Franz Plasser Bahnbaumaschinen Industrie GmbH
Current assignee: Franz Plasser Bahnbaumaschinen Industrie GmbH
Priority date: 1977-09-07
Filing date: 1978-02-21
Publication date: 1980-10-01
Also published as: CH630426A5; AU3296278A; DD135633A5; JPS5444298A; DE2801111C2; ATA644377A; AU518284B2; AT359107B; DE2801111A1; ZA78162B; IT7822012A0; ES466376A1; IT1094328B

Abstract

In order to increase the grinding performance and the smoothing effect, the grinding tools (31) are provided, in addition to the continuous grinding motion caused by the progressive advancement of work, with a further grinding motion which superposes the first-mentioned grinding motion. This additional grinding motion is carried out in alternating, mutually opposite directions by a drive device (44). The latter comprises a double-armed lever (45), which can rotate about a shaft (46), and a single-armed lever (47) which can pivot about a pin (48). The two levers (45, 47) are connected to each other in an articulated manner via a rigid connecting strap (49). The levers (45, 47) can be set in pivoting motion via an eccentric shaft (50) and a crank mechanism (51). Said pivoting motion can be transmitted, via rods (52), onto the tool holder (27) accommodating the grinding tools (31). <IMAGE>

Description

(54) A PROCESS AND A RAIL GRINDING VEHICLE FOR SMOOTHING OUT IRREGULARITIES IN THE SURFACE OF RAILHEADS (71) We, FRANZ PLASSER BAHN BAUMASCHINEN INDUSTRIEGESELLSCHAFT m.b.H. of 3 Johannesgasse, Vienna I, Austria, an Austrian Company, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following state ment: - This invention relates to a process for smoothing out irregularities in the upper surface and/or shoulder of a railhead by grinding, in which at least one grinding tool or, optionally, several grinding tools combined into groups, which is/are moved along with a grinding vehicle and pressed onto the treatment zones to be ground, carries/carry out a grinding movement on these treatment zones during and, as a result of, the continuous advance of the vehicle.

In track maintenance work, ever increasing importance. is being attributed to the repair and maintenance of the railhead surfaces of the tracks by regular grinding by means of travelling rail grinding machines in order to eliminate ridging, undulation and other irregularities occurring on the railhead surfaces. Irregularities such as these adversely affect the running properties of railway vehicles to such an extent that not only is passenger comfort reduced, speed limits also have to be imposed in many cases on safety grounds. In addition, however, irregularities of the type in question are also extremely damaging to the track itself and result in excessive stressing of the rails by vibration, in loosening of the rail fastenings and also in changes in the position of the track and loosening of the ballast bed, particularly in the region of the sleeper bearing surfaces.Accordingly, it is essential for the track to be restored to its required condition in regard to the surface quality of the rails by grinding, as far as possible while the ridges and undulations are actually in the process of formation.

In conventional processes of the type in question, either rotary grinding wheels according to German Patent No. 1,206,461 9r grindstones, so-called rubbing blocks, in surface-to-surface contact with the railhead according to German Patent No. 1,021,746 are merely moved over the rail at the speed of travel of the grinding vehicle. Although, in the first case, the irregularities can be sufficiently smoothed out during a single passage of the vehicle or several grinding vehicles linked together to form a train by the provision of a correspondingly large number of grinding wheels, the inadequate profiling of the railheads attributable to the bevel-edge grinding technique used has an adverse effect.In addition, the rate of advance obtainable with this process is low and only amounts to about 3000 m/h, with the result that the grinding performance is correspondingly low, apart from which considerable difficulties are encountered where this process is used because grinding can only be carried out during correspondingly long intervals between trains.

Although in the conventional method considerably higher rates of advance of the grinding vehicle can be obtained by using rubbing blocks instead of grinding wheels as the grinding tools, it is only possible to obtain a fairly minimal depth of erosion per pass, even where several rubbing blocks are arranged one behind the other, with the result that several passes are required for eliminating the coarsest irregularities, resulting in a poor grinding performance, based on the ground track. In addition, the continuity of the grinding process over relatively long sections of track also suffers from the large number of passes required.

In addition, on account of the high contactpressure forces required and the resulting frictional resistance, there is a limit to the number of rubbing blocks which can be arranged one behind the other in the longitudinal direction of the track if the rail is not to be overstressed.

The object of the present invention is to provide a process for grinding rails by means of a grinding vehicle and a grind vehicle for carrying out the process by which it is possible to obtain a high grinding performance and, at the same time, a high grinding quality.

According to the invention, this object is achieved in that, in the process described above, additional grinding movements produced by a drive mechanism are carried out in alternate, opposite directions, in the longitudinal direction of the track, on the upper surface and/or shoulder of the railhead at the same time as and superimposed upon the grinding movement caused by the advance of the vehicle. These reciprocating grinding movements superimposed upon the advance of the machine provide for a considerable increase in the effective grinding path of the grinding tools or groups of grinding tools by comparison with grinding tools which are only advanced at the rate of travel of the machine, with the result that it is possible to increase the grinding performance by a multiple factor.By superimposing the continuous advance movement and the simultaneous, additional grinding movements in the longitudinal direction of the track, each surface zone of the rail is repeatedly covered by the individual grinding tools, with the result that not only is the depth of erosion obtainable over a single grinding run increased by a multiple factor, a high quality grinding result with a particular smoothing effect is also obtained. This smoothing effect is obtained not only where rubbing blocks are used as the grinding tools, but also at least partly in cases where rotating grinding discs are used because in their case, the formation of chatter marks is largely suppressed by the additional movement of the grinding wheels relative to the rail surface.

However, the process according to the invention provides for the rapid erosion not only of ridges, but also of surface faults of relatively long wavelength. This can be explained by the fact that the copying of the relatively long-wave surface faults, which is unavoidable to a small extent, now occurs not only in the direction of travel of the grinding vehicle, as was hitherto the case, but also in the opposite direction, resulting in advantageous equalisation which considerably improves the result of grinding.

In one particularly advantageous variant of the process according to the invention these additional grinding movements are carried out, still in opposite directions, on at least two adjacent zones of the upper surface and/or shoulder of the railhead. In this case, the reaction forces generated by the friction of the grinding tools are always directed opposite one another, thus avoiding vibration of the track.

The invention also relates to a rail grinding vehicle for carrying out the process according to the invention which is equipped with tool holders for the grinding tools which are designed to be supported by the frame of the vehicle and to be moved towards and pressed against the railheads to be ground.The invention is characterised in that each of the tool holders equipped with grinding tools, preferably rubbing blocks, is pivotally connected to a drive mechanism which produces a reciprocating movement relative to the frame of the vehicle, in the longitudinal direction thereof, through a connecting element designed to transmit tractive and compressive forces, the points at which the connecting element is linked to the tool holder and the drive mechanism being situated at substantially the same distance from the plane of the track delimited by the wheel contact points and the connecting element or at least a section thereof adjoining the tool holder always extending in a plane running perpendicularly of the track plane and including the direction of the relative movement of the tool holder.As a result, the force applied to the tool holder acts in the direction of the relative movement or substantially parallel to the plane of the track. Even in cases where the drive mechanism producing the reciprocating relative movement of the tool holder is in the form of an eccentric arrangement, for example a pivotal lever or a crank shaft, no significant vertical force components act on the tool holders, with the result that the grinding tools can be pressed uniformly onto the rails, thereby avoiding troublesome differences during the grinding operation.

In one preferred embodiment of a rail grinding vehicle according to the invention, the drive mechanism for two tool supports arranged adjacent one another in the longitudinal direction of the vehicle is formed by two interconnected levers which are designed to be oscillated about horizontal axes by means of a motor, to whose ends nearer the plane of the track the connecting elements leading to the tool supports are pivotally connected and which are joined together through a connecting element transmitting tractive and compressive forces which is linked to the second end of one lever - a double-armed lever - and to the other lever - a one-armed lever.An oppositely directed movement of the two tool supports is obtained in simple manner by the connection and common actuation of the one-armed lever and the two-armed lever which, at the same time, afford the possibility of arranging the points at which the connecting elements are linked to thelevers and to the tool supports at an equal distance from the upper surface of the rail, thereby enabling simple rods to be used for the connecting elements.

Although, as a result of the pivoting movement of the levers, the distance between the upper surface of the railhead and the points at which the connecting elements are linked to these levers fluctuates between two extreme values, the tool holders are not affected to any significant extent, particularly where correspondingly long connecting elements are provided, because in spite of this the connecting elements run substantially parallel to the upper surface of the rail.

Accordingly, no significant vertical force components act on the tool holders, enabling the tool holders to be uniformly pressed on by means of suitable pressure cylinders.

In another preferred embodiment, the connecting element pivotally connected to a drive mechanism in the form of an eccentric arrangement and to the tool holder comprises a link sliding in a guide parallel to the plane of the track, of which the preferably variable distance from the upper surface of the railhead is substantially equal to the distance of the point at which the connecting element is linked to this tool holder. This arrangement ensures that that region of the connecting element which adjoins the tool holders always runs substantially parallel to the plane of the track so that no vertical force components are able to act on the connected tool holder, even when the drive mechanism is in the form of a rotating crank shaft.Basically, it is also possible in this embodiment to take into account the wear of the grinding tools and to lower the link guide accordingly during the grinding operation in order to keep the distance of the link and the point at which it is connected to the tool holder from the plane of the track permanently the same.

The grinding tools, particularly rubbing blocks, may be held in the tool holders in different ways, according to requirements.

Thus, it is of advantage for smoothing out ridges and also relatively long-wave surface faults to provide a rail grinding vehicle according to the invention in which the outer of the grinding tools, particularly rubbing blocks, of which there are at least three, are rigidly held in at least one tool holder, whilst the central spring-loaded grinding tool is mounted for displacement perpendicularly of the plane of the track. In this case, the ridges are smoothed out for the most part by the central spring-loaded grinding tools whilst the relatively longwave surface faults are corrected by the outer, rigidly mounted grinding tools.

If, by contrast, the surface faults to be eliminated are primarily of the relatively longwave type, it is of advantage to provide a rail grinding vehicle in which all the three grinding tools, particularly rubbing blocks, of which there are at least three, are rigidly held in at least one of the tool holders. By rigidly mounting all the grinding tools arranged in a tool holder, the grinding tools are prevented from dropping into a wave trough of the surface faults and from eroding material there as well. A rail grinding vehicle according to the invention may of course also be equipped with tool holders in which the central grinding tools are differently mounted.

Stops may be provided for limiting the adjustment of each tool holder to a value determined by the maximum permitted wear of the grinding tools. This reliably prevents the grinding tools from being excessively worn in which case their holders would begin to rub on and damage the rail surfaces.

In one advantageous embodiment, the tool holder is provided at its two ends with flanged wheels mounted in spring-loaded rockers, these rockers preferably being designed for limiting the adjustment of the tool holder. The flanged wheels provide for effective guiding of the tool holders and the fact that they are mounted in spring-loaded rockers considerably facilitates accurate placement of the grinding tools on the rails when the tool holders are lowered, because in this case the flanged wheels provide for corresponding alignment of the tool holder while it is actually being lowered. At the same time, these rockers represent a simple means of limiting the adjustment of the tool holder with which the rockers come into contact when a certain degree of adjustment has been reached.

In order effectively to guide the tool holders along the rails, provision is also made in accordance with the invention for two tool holders arranged symmetrically to the central longitudinal plane of the track to be joined together by means of two pistonand-cylinder units. This provides for effective adaptation to changes in gauge.

The invention is described in more detail in the following with reference to the accompanying drawings, although it is by no means confined to the embodiments illustrated therein. In the accompanying drawings: Figure 1 is a diagrammatic illustration explaining the process.

Figure 2 is a diagrammatic side elevation of a rail grinding vehicle according to the invention; Figure 3 is a diagrammatic side elevation of another embodiment with a modified drive mechanism.

Figure 4 is a section on the line IV-IV of Figure 3.

Figure 5 is a section on an enlarged scale through a tool holder.

Figure 6 is a diagrammatic plan view of a group of tool holders.

As can be seen from Figure 1, the rail 5 is ground at its surface by superimposed grinding movements of the grinding tools 1. One of these grinding movements is produced by the continuous advance (arrow 2) of the grinding vehicle provided with the grinding tools. The other grinding movements which occur at the same time and which are superimposed upon the movement produced by the advance (arrow 2) are carried out in alternate, opposite directions, preferably in the longitudinal direction of the track (arrows 3, 4 and 3', 4') and are produced by a drive. The superimposed grinding movements occurring in alternate directions, which are carried out on two adjacent zones of the rail 5, are with advantage directed opposite to one another.

For example, one of the grinding tools, namely the grinding tool 1, carries out a movement in the direction of the arrows 3 and 4 whilst, at the same time, the other grinding tool carries out an oppositely directed movement in the direction of the arrows 3' and 4'.

The rail grinding vehicle 6 shown in Figure 2 is intended to travel continuously along the rails 5 and 5' of a laid track 9 by means of two undercarriages 7 incorporating driven wheel sets 8. The systems by which the vehicle 6 is propelled, controlled and supplied with power and working fluid are arranged on the vehicle frame 10 which, at either end, is equipped with pull and buff couplings 11 to enable the vehicle 6 to be incorporated into a train formation. These systems include the drive motor 12 a compressor unit 13 with a pressure tank 14, a water tank 15 with a valve assembly 16 and a central control unit 17 which is arranged inside the driver's compartment 18 and which comprises the arrangements necessary for operating and monitoring the machine.The drive link between the motor 12 and the two wheel sets 8, which is normally in the form of a multistage gear unit and drive shafts, is diagrammatically indicated in the drawing by dash/two-dot lines 19. In addition, the motor 12 is linked to the central control unit 17 through a control line 20. A compressed air line 21 extends from the pressure tank 14 of the compressor unit 13, being controllable by a valve assembly 22 which is also connected to the control unit 17 by a line 23. The valve assembly 16 of the water tank 15 is connected to the control unit 17 through another control line 24 shown in chain lines.

For each of the rails 5 and 5', the vehicle 6 comprises groups 25, 26 and 25', 26' of grinding tools which are arranged one behind the other in the longitudinal direction of the machine between the two undercarriages 7. In the embodiment illustrated, each of these groups of grinding tools consists of three grinding tools 31 in the form of rubbing blocks which are arranged one behind the other in the longitudinal direction of the rails 5 and 5' and which are mounted together on a tool holder 27. Each tool holder 27 is suspended pendulumfashion from the vehicle frame 10 by means of two telescopic, i.e. variable-length guides which, in the case of the embodiment illustrated, are in the form of pneumatic piston-and-cylinder units 28 which are connected to the compressed air line 21 and which are controllable by means of the valve assembly 22.Each tool holder 27 is guided in the longitudinal direction of the associated rail 5 or 5' by means of two flanged wheels 30 arranged in double rockers 29. As can be seen in particular Figure 5, each rocker 29 is pivotal about a pin 54 arranged in the tool holder 27 and comprises a rod 55 which extends through the tool holder 27 and to whose upper end is attached a tension spring 56 whose second end is anchored to a rod 57 secured to the tool holder.

As can be seen in particular from Figure 5, the individual, substantially parallelepipedic rubbing blocks 31, of which the underneath preferably has a profile matching the required profile of the railhead, are each releasably fixed to a holding shoe 32 by means of screws 33. By means of a vertical guide bolt 34 arranged on its upper side, each holding shoe 32 is guided for vertical adjustment on the tool holder 27 in a bore of a guide member 35 fixed to the tool holder 27 by means of screw bolts 60 and rests either resiliently or rigidly on a supporting cap 36 rigidly secured to the tool holder 27 according to the particular grinding principle selected. The vertical metal plates supporting the cap 36 are also used for joining the two upright longitudinal plates of the tool holder 27. In Figure 5, the chain lines denote a rigid mounting of a supporting shoe 32 by means of a metal sleeve 38 which rests on a disc 39 lying on a shoulder of the guide bolt 34, whilst the solid lines represent a resilient mounting by means of a spring 40 of an elastic plastics material. The spring 40 may of course also be in the form of a plate spring or helical spring. The holding shoe 32 is fixed by means of the threaded extension 41 projecting through the supporting cap 36 and the nut 42. To prevent the holding shoe 32 from rotating and to align the rubbing block 31 in the longitudinal direction of the rail, two guides lugs 32 are arranged on the upper side of each holding shoe 32, sliding on an inner surface of the tool holder 27.

For cooling the rubbing blocks 31 and for flushing away the grinding dust which accumulates during the grinding operation, water spray nozzles 43 are arranged on the tool holders 27, being directed onto the spaces between the successive rubbing blocks 31.

Another two water spray nozzles 43 are respectively arranged immediately in front of and behind each group of grinding tools.

The spray nozzles 43 are connected to the water tanks 15 by pipes shown in chain lines, the flow of water to the spray nozzles 43 being centrally controlled from the control unit 17.

As already mentioned, a simultaneous, additional working movement in the longitudinal direction of the track, superimposed upon the continuous advancing movement in the direction of the arrow 2, is imparted to the rubbing blocks 31 or rather to the individual groups of grinding tools. To this end, a reciprocating working movement directed longitudinally of the track is imparted to the two groups 25 and 26 of grinding tools associated with one rail, for example the rail 5, by a common drive unit 44 so that they move in opposite directions, as indicated by the arrows 3, 4 and 3', 4'. By the opposite directions of movement of the two groups 25, 26 of grinding tools, the longitudinal forces of the two groups of grinding tools caused by the friction between the rubbing blocks 31 and the surface of the railhead are at least approximately compensated.

The drive mechanism 44 includes a double-armed lever 45 which is secured to the shaft 46 extending transversely of the longitudinal axis of the vehicle, and a one-armed lever 47 which is pivotal about the pin 48 and which is pivotally connected to the lever 45 through the rigid connecting plate 49.

The two levers 45 and 47 can therefore be pivoted together through an eccentric shaft 50 connected to the motor and a crank gear 51. The pivoting movement of the two levers 45 and 47, which is always oppositely directed at their ends facing the plane of the track, is transmitted to the tool holders through the connecting elements in the form of rods 52 pivotally connected to the levers and to the tool holders 27. The points 72, 73 at which the rods 52 are pivotally connected to the levers 45, 47 and to the tool holders 27 are at substantially the same distance from the rail surface, each of the connections to the levers 45, 47 naturally fluctuating in operation on account of the pivoting movement.

By controlling the rotational speed of a drive motor, for example in the form of a hydraulic motor, the rotational speed of the eccentric shaft 50 and hence the frequency of the additional, reciprocating movement of the groups of grinding tools can be varied, for example in dependence upon the rate of travel of the vehicle 6, and adapted to meet particular requirements. A frequency of approximately 8 cycles per second may be taken as a guide line for an average frequency. The overall stroke of the reciprocating working movement should best amount to at least half, but preferably to about two thirds of the length of a single rubbing block 31. In order to be able to vary the overall stroke as and when necessary, the crank pin 53 for example may be arranged for radial adjustment on the eccentric shaft 50.

For fitting and for replacing rubbing blocks 31 and also for when the vehicle 6 is in transit, the tool holders 27 are raised by means of the pneumatic piston-and-cylinder units 28. The rubbing blocks 31 are introduced into their holding shoes 32 from below. Differences in the degree of wear of the rubbing blocks of a group of grinding tools can be compensated by using metal sleeves 38 of different height, particularly where the holding shoes 32 are rigidly mounted. The tooling of the vehicle 6 may be largely adapted to meet the particular requirements of the section of track to be worked by suitably selecting the material, the profiling and the granulometry of the rubbing blocks 31.For example, it is possible to use rubbing blocks 31 having a lower surface which is flat to begin with and then automatically assumes the shape of the railhead after a relatively short period in grinding contact therewith. In this way, a continuously curved rail surface is obtained.

For treating the entire rail level, including the inner shoulder of the railhead, it is advisable to use rubbing blocks 31 with a preformed profile resembling a wheel flange. In order to obtain a smoothing effect progressing in the direction of travel on the surface of the railhead, the groups of grinding tools may also be formed by rubbing blocks 31 of different granulometry. In addition, it is possible to graduate the contact pressure of the successive rubbing blocks 31 of each group of grinding tools in the longitudinal direction of the track.

In addition, the tools combined into a group of tools may be differently held in the tool holder 27. For example, it is possible for the outer rubbing blocks 31 to be rigidly held by means of the metal sleeves 38 and for the central rubbing blocks to be resiliently held by means of the spring 40 in the form of an elastic sleeve, thereby enabling relatively long-wave surface faults and ridges to be eliminated at one and the same time. It is of course also possible, depending upon the nature of the predominantly surface faults to be eliminated, for all the rubbing blocks of one group 25 or 26 to be held in the same way.

In the operation of the rail grinding vehicle 6, the tool holders 27 and hence the rubbing blocks 31 are pressed onto the surface zones of the rail 5, 5' to be ground by means of piston-and-cylinder units 28.

The drive mechanism 44 for the reciprocating working movement of the groups 25, 26 of grinding tools is started up at the same time as the vehicle drive motor. By superimposing the reciprocating working movement on the grinding movement caused by the continuous advance of the grinding vehicle 6, the grinding path of each individual rubbing block 31 is considerably increased by comparison with that of a rubbing block which is merely advanced at the rate of travel of the vehicle.

In order to limit the adjustment of the rubbing block 31 to a value determined by their maximum permitted wear, a stop 58 is provided on the rocker 29, as shown in Figure 5. This stop 58 comes into contact with the underneath of the tool holder 27 when the rocker 29, as a result of the downwardly directed adjusting movement of the tool holder 27, has been pivoted upwards to a sufficient extent against the force of the spring 56. When the tool support 27 is raised, for example when the vehicle is in transit, the rod 55 connected to the double rocker 29 comes into contact with a crossplate 59 of the tool holder 27 and limits the downwardly directed pivoting movement of the rocker 29.

Figure 3 shows an embodiment with a modified drive mechanism 44' in which a double armed lever 61 is fixed to the shaft 46 arranged transversely of the longitudinal axis of the vehicle. The rod 52 leading to a tool holder 27 is pivotally connected to that end of the double armed lever 61 which faces the plane of the track, whilst the crank gear 51 pivotally connected to the eccentric shaft 50 and a second connecting element 62 leading to a second tool holder 27 are pivotally connected to the second end of the double armed lever 61.

This connection element 62 is provided with a link 63 which comprises a bifurcate link head 65 and which slides in a guide member 64 formed with a T-groove. This guide member 64 is kept at a certain distance from the upper surface of the rail by the cylinder-and-piston unit 66, of which the cylinder is fixed to the vehicle frame 10, and engages through two guide bolts 67 behind a vertical plate of the vehicle frame 10.

By pivotally connecting one connecting element 62, 52 leading to a tool holder 27 to each of the two ends of the double-armed lever 61, an oppositely directed movement of the two tool holders 27 connected to the lever 61 is obtained. The distance A of the point 72 at which the rod 52 is pivotally connected to the tool holder 27 from the upper surface of the rail is substantially equal to the distance A' of the point 73 at which the rod 52 is pivotally connected to the lever 61 which changes continuously in operation on account of the pivoting movements. By contrast, the distance B' of the link 63 or its axis from the upper surface of the rail can be adjusted exactly equal to the distance B of the point 72 at which the connecting element 62 is pivotally connected to the associated tool holder 27 and can also be maintained in operation.In this way, the force applied to the associated tool holder is always directed parallel to the upper surface of the rail. It is of course also possible for both tool holders 27 to be connected to the drive mechanism through connecting elements 62 each comprising a link 63 sliding in a guide, in which case the drive mechanism may even be in the form of a rotating crank shaft to which the connecting elements are pivotally connected with an angular stagger of 1800.

As shown in Figure 6, two tool holders arranged symmetrically to the longitudinal central plane of the track are best joined together by two piston-and-cylinder units 68 which enable the guide elements, such as for example flanged wheels 30 or vertical guide bolts, to be applied to the inner shoulders of the railheads 71, 71', even in the event of changes in gauge.

The tool holders 69 shown diagrammatically in Figure 6 are slightly modified by comparison with the tool holders 27 shown in Figures, 2, 3 and 5, and, instead of flanged wheels 30, comprise vertically arranged guide bolts 70 for guiding along the shoulders of the railhead. In addition, the cylinder-and-piston units 68 may be pivotally connected to the tool holders for permanently guiding them without play along a track of varying gauge.

Attention is drawn to our copending Application No. 6796/78 (Serial No.

1576192) corresponding to Austrian Application A1150/77 (folio 35282) which describes and claims a machine which operates in accordance with claim 1 herein.

WHAT WE CLAIM IS: 1. A process for smoothing out irregularities in the upper surface and/or shoulder of a railhead by grinding, in which at least one grinding tool or, optionally, several grinding tools combined into groups, which is/are moved along with a grinding vehicle and pressed onto the treatment zones to be ground, carries or carry out a grinding movement on these treatment zones during and as a result of the continuous advance of the vehicle, characterised in that additional grinding movements produced by a drive mechanism are carried out in alternate,

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **.

way.

In the operation of the rail grinding vehicle 6, the tool holders 27 and hence the rubbing blocks 31 are pressed onto the surface zones of the rail 5, 5' to be ground by means of piston-and-cylinder units 28.

The drive mechanism 44 for the reciprocating working movement of the groups 25, 26 of grinding tools is started up at the same time as the vehicle drive motor. By superimposing the reciprocating working movement on the grinding movement caused by the continuous advance of the grinding vehicle 6, the grinding path of each individual rubbing block 31 is considerably increased by comparison with that of a rubbing block which is merely advanced at the rate of travel of the vehicle.

In order to limit the adjustment of the rubbing block 31 to a value determined by their maximum permitted wear, a stop 58 is provided on the rocker 29, as shown in Figure 5. This stop 58 comes into contact with the underneath of the tool holder 27 when the rocker 29, as a result of the downwardly directed adjusting movement of the tool holder 27, has been pivoted upwards to a sufficient extent against the force of the spring 56. When the tool support 27 is raised, for example when the vehicle is in transit, the rod 55 connected to the double rocker 29 comes into contact with a crossplate 59 of the tool holder 27 and limits the downwardly directed pivoting movement of the rocker 29.

Figure 3 shows an embodiment with a modified drive mechanism 44' in which a double armed lever 61 is fixed to the shaft 46 arranged transversely of the longitudinal axis of the vehicle. The rod 52 leading to a tool holder 27 is pivotally connected to that end of the double armed lever 61 which faces the plane of the track, whilst the crank gear 51 pivotally connected to the eccentric shaft 50 and a second connecting element 62 leading to a second tool holder 27 are pivotally connected to the second end of the double armed lever 61.

This connection element 62 is provided with a link 63 which comprises a bifurcate link head 65 and which slides in a guide member 64 formed with a T-groove. This guide member 64 is kept at a certain distance from the upper surface of the rail by the cylinder-and-piston unit 66, of which the cylinder is fixed to the vehicle frame 10, and engages through two guide bolts 67 behind a vertical plate of the vehicle frame 10.

By pivotally connecting one connecting element 62, 52 leading to a tool holder 27 to each of the two ends of the double-armed lever 61, an oppositely directed movement of the two tool holders 27 connected to the lever 61 is obtained. The distance A of the point 72 at which the rod 52 is pivotally connected to the tool holder 27 from the upper surface of the rail is substantially equal to the distance A' of the point 73 at which the rod 52 is pivotally connected to the lever 61 which changes continuously in operation on account of the pivoting movements. By contrast, the distance B' of the link 63 or its axis from the upper surface of the rail can be adjusted exactly equal to the distance B of the point 72 at which the connecting element 62 is pivotally connected to the associated tool holder 27 and can also be maintained in operation.In this way, the force applied to the associated tool holder is always directed parallel to the upper surface of the rail. It is of course also possible for both tool holders 27 to be connected to the drive mechanism through connecting elements 62 each comprising a link 63 sliding in a guide, in which case the drive mechanism may even be in the form of a rotating crank shaft to which the connecting elements are pivotally connected with an angular stagger of 1800.

As shown in Figure 6, two tool holders arranged symmetrically to the longitudinal central plane of the track are best joined together by two piston-and-cylinder units 68 which enable the guide elements, such as for example flanged wheels 30 or vertical guide bolts, to be applied to the inner shoulders of the railheads 71, 71', even in the event of changes in gauge.

The tool holders 69 shown diagrammatically in Figure 6 are slightly modified by comparison with the tool holders 27 shown in Figures, 2, 3 and 5, and, instead of flanged wheels 30, comprise vertically arranged guide bolts 70 for guiding along the shoulders of the railhead. In addition, the cylinder-and-piston units 68 may be pivotally connected to the tool holders for permanently guiding them without play along a track of varying gauge.

Attention is drawn to our copending Application No. 6796/78 (Serial No.

1576192) corresponding to Austrian Application A1150/77 (folio 35282) which describes and claims a machine which operates in accordance with claim 1 herein.

WHAT WE CLAIM IS: 1. A process for smoothing out irregularities in the upper surface and/or shoulder of a railhead by grinding, in which at least one grinding tool or, optionally, several grinding tools combined into groups, which is/are moved along with a grinding vehicle and pressed onto the treatment zones to be ground, carries or carry out a grinding movement on these treatment zones during and as a result of the continuous advance of the vehicle, characterised in that additional grinding movements produced by a drive mechanism are carried out in alternate,

opposite direction, in the longitudinal direction of the track, on the upper surface and/or shoulder of the railhead at the same time as and superimposed upon the grinding movement caused by the advance of the vehicle.
2. A process as claimed in claini 1, characterised in that these additional grinding movement are always carried out in opposite directions on at least two adjacent zones of the upper surface and/or shoulder of the railhead.
3. A rail grinding vehicle for carrying out the process claimed in claim 1 or 2, having a frame equipped with tool holders for the grinding tools which are supported by the frame of the vehicle and to be moved towards and pressed against the railheads to be ground, characterised in that each of the tool holders equipped with grinding tools is pivotally connected to a drive mechanism, which produces a reciprocating movement relative to the frame of the vehicle, in the longitudinal direction thereof, through a connecting element designed to transmit tractive and compressive forces, the points at which the connecting element is linked to the tool holder and the drive mechanism being situated at substantially the same distance from the plane of the track as delimited by the wheel contact points, and the connecting element or at least a section thereof adjoining the tool holder always extending in a plane running perpendicular of the track plane and including the direction of the relative movement of the tool holder.
4. A rail grinding vehicle as claimed in claim 3 in which the grinding tools are rubbing blocks.
5. A rail grinding vehicle as claimed in claim 3 or 4 characterised in that the drive mechanism for two tool supports arranged adjacent to one another in the longitudinal direction of the vehicle is formed by two interconnected levers which are designed to be oscillated about horizontal axes by means of a motor, to whose ends nearer the plane of the track the connecting elements leading to the tool supports are pivotally connected and which are joined together through a connecting element transmitting tractive and compressive forces which is linked to the second end of one lever which is a double armed lever and to the other lever which is a one-armed lever.
6. A rail grinding vehicle as claimed in claim 3, 4, or 5 characterised in that the connecting element pivotally connected to a drive mechanism in the form of an eccentric arrangement and to the tool holder comprises a link which slides in a guide parallel to the plane of the track and of which the distance from the upper surface of the railhead is substantially equal to the distance of the point at which the connecting element is pivotally connected to this tool holder.
7. A rail grinding vehicle as claimed in claim 6 in which the said distance from the upper surface of the rail head is adjustable.
8. A rail grinding vehicle as claimed in any of claims 3 to 7 characterised in that the outer of the grinding tools, of which there are at least three, are rigidly held in at least one tool holder whilst the central grinding tools are spring loaded and mounted for displacement perpendicular to the plane of the track.
9. A rail grinding vehicle as claimed in any of claims 3 to 7, characterised in that all the grinding tools, of which there are at least three, are rigidly mounted in at least one tool holder.
10. A rail grinding vehicle as claimed in any of claims 3 to 9, characterised in that stops are provided for limiting the adjustment of each tool holder to a value determined by the maximum permitted wear of the grinding tools.
11. A rail grinding vehicle as claimed in any of claims 3 to 10, characterised in that the tool holder is provided at both ends with flanged wheels which are mounted in springloaded rockers, these rockers being designed to limit the adjustment of the tool holder.
12. A rail grinding vehicle as claimed in any of claims 3 to 11, characterised in that two tool holders arranged symmetrically about the longitudinal central plane of the track are joined together by means of two cylinder-and-piston units.
13. A rail grinding vehicle substantially as herein described with reference to the accompanying drawings.
14. A method of smoothing a rail head, substantially as herein described with reference to the accompanying drawings.