GB1576192A

GB1576192A - Travelling rail grinding machine

Info

Publication number: GB1576192A
Application number: GB679678A
Authority: GB
Original assignee: Franz Plasser Bahnbaumaschinen Industrie GmbH
Current assignee: Franz Plasser Bahnbaumaschinen Industrie GmbH
Priority date: 1977-02-21
Filing date: 1978-02-21
Publication date: 1980-10-01
Also published as: AU3296178A; DD135632A5; DE2801110A1; SU913949A3; HU177360B; CH628695A5; AU518415B2; YU21778A; AT357593B; NL7801916A; AR215676A1; ATA115077A; DE2801110C2; TR20407A

Abstract

Opposite a machine frame (7) there are grinding tools (22, 23) which are arranged in a vertically adjustable manner and one behind the other in groups in the longitudinal direction of the rail, can be pressed against the rail-head surface areas to be ground and are arranged on a tool frame (25). At least one grinding tool or one grinding-tool group is equipped with a drive device (39) for the simultaneous additional working movement in the longitudinal direction of the machine, which additional movement is superimposed on the continuous travelling movement of the machine or the tool frame. This rail-grinding machine serves to grind down irregularities on the rail-head surfaces. A uniform, standard grinding result is ensured by the working movement superimposed on the travelling movement of the machine. <IMAGE>

Description

(54) A TRAVELLING RAIL GRINDING MACHINE (71) We, FRANZ PLASSER BAHN BAUMASCHINEN- INDUSTRIEGESELLSCHAFT mbH, of 3 Johannesgasse Vienna 1, 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 statement: This invention relates to a travelling rail grinding machine for smoothing out irregularities on the surfaces of the rail heads.

In track maintenance work, everincreasing importance is being attributed to the repair and maintenance of the rail head surfaces of the tracks by regular grinding by means of travelling rail grinding machines.

As a result of growth in traffic density and ever-increasing train weights and speeds, the rails are stressed to such an extent that ridging, undulation and other irregularities are occurring more frequently and to an increased extent on the surfaces of the rail heads. Apart from the fact that these deformations and areas of wear on the surfaces of the rail heads adversely affect the running properties of railway vehicles and, for this reason, have frequently resulted in the imposition of speeds limits on safety grounds, they also interfere with the comfort of the passengers as a result of the vibration and droning noise which they produce in the carriages. However, ridging and the like on the surfaces of the rail heads is also extremely damaging to the track itself. The rails are overstressed by vibration which loosens the rail fastenings.Further consequences of this vibration include 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.

Travelling rail grinding machines differing in their construction and cooling have been developed with a view to eliminating the surface faults referred to above. A rail grinding waggon equipped with "rotary" grinding tools is known for example from German Patent No. 1,206,461. In this machine, two grinding tool units mounted on separate tool carriers equipped with their own undercarriages are arranged one behind the other in the longitudinal direction of the track between the two undercarriages of the machine. Each grinding tool unit comprises for each rail three grinding assemblies mounted for separate vertical adjustment which constists of a drive motor with a vertical shaft and a grinding wheel arranged at the lower end of the shaft.The rail grinding waggon is equipped with an elaborate, multi-component control system for controlling the pressure with which each individual grinding assembly is pressed onto the surface of the rail head. Apart from the considerable structural outlay involved in this control system, the disadvantage of this machine is that it can only be used for treating relatively narrow surface areas of the rail head, but not for treating the shoulders of the rail head. Accordingly, it is not possible even remotely to restore the rail head to its original profile by grinding.

Since the grinding wheels are for the most part only in linear contact with the surface of the rail head, the grinding performance of this machine, in other words the degree of erosion which can be obtained during a grinding run, is relatively low.

It is also known that, in order to reduce the number of grinding runs required to smooth out ridges and other irregularities on the rails which can only be carried out during prolonged intervals between trains on account of the relatively low progress of work, a relatively large number of grinding waggons equipped with rotating grinding tools can be combined with one another to form a complete rail grinding train. This grinding train is normally hauled over the sections of track to be treated by two locomotives with low-geared motors. Apart from the high production costs which they involve, rail grinding trains of this type have to be attended by numerous operators and require disproportionately high outlay in regard to maintenance and organisation for the operational planning and economic utilization of these trains.Further disadvantages of this machine equipped with "rotary" grinding tools include the considerable technical outlay involved in the correct guiding and control of the grinding tools, the defective profiling of the ground surfaces of the rail heads (bevel-edge grinding) and the problems caused by the presence of magnetic rail contacts, level crossings and other obstacles situated within the working range of the grinding wheels.

Rail grinding machines which function on another known grinding principle, for example according to German Patent No.

1,021,746, are provided with grind stones in the form of so-called rubbing blocks which are capable of being pressed onto the surface of the rail head so that they come into surface-to-surface contact therewith.

Unfortunately, the grinding performance of these rubbing blocks which are generally arranged in groups one behind the other in the longitudinal direction of the machine and which, during the grinding run, are only drawn over the surface of the rail head at the rate of advance of the machine is relatively low. Repeated grinding runs are required to remove even the most coarse irregularities from the surface of the rail head. As a result, there is also no longer ay guarantee of the continuity of the grinding result over relatively long sections of track.

For these reasons, machines of this type have hitherto largely been used for minor purposes or for applications requiring only a minimal grinding performance, as for example in the grinding of tramlines.

Rubbing blocks of the type in question are also used in stationary installations for smoothing the surface of new and old rails.

One known installation of this type, for example according to German Auslegeschrift No. 1,277,()69, comprises a roller track on which the rail to be treated is slowly advanced at a constant speed. A tool unit consisting of three rubbing blocks mounted for separate vertical adjustment and arranged one behind the other in the longitudinal direction of the rail is arranged on a tool frame guided by means of rollers in the longitudinal direction of the rail. A relatively slow, periodically reciprocating movement is imparted to the tool frame in the longitudinal direction of the rail by a stationary eccentric drive.The force with which the rubbing blocks are pressed onto the surface of the rail is staggered in such a way that the first rubbing block (looking in the direction of movement of the rail) which is under the greatest contact pressure roughens the surface of the rail head and removes the tops of the ridges during the reciprocating movement of the tool frame.

The other two rubbing blocks which are under a reduced contact pressure are responsible for the rough and fine smoothing of the rail surface. This known installation is used above all for smoothing profiled new rails which have been pretreated by means of a milling machine.

The object of the present invention is to provide a travelling rail grinding machine of high performance which obviates the disadvantages of the relatively expensive constructions referred to above and which enables all the irregularities encountered in practice on the surfaces of rail heads to be eliminated, thereby largely restoring the rail head to the required profile. In addition, the machine according to the invention is intended to guarantee a uniform, consistent grinding result irrespective of the particular geometry and surface condition of the section of track being worked.

According to the invention there is provided a travelling rail grinding machine for smoothing out irregularities on the surfaces of the rail heads, comprising grinding tools which are mounted for vertical adjustment on the machine frame, are disposed one behind another in the longitudinal direction of the machine, are designed to be pressed onto the surface areas of the rail head to be ground, and are arranged on a tool frame, characterised in that at least one grinding tool or one group of grinding tools is equipped with a drive mechanism for imparting a simultaneous additional working movement in the longitudinal direction of the machine, superimposed upon the continuous advancing movement of the tool frame.

By virtue of this arrangement, it is possible to increase the performance of a grinding machine by a multiple factor surprisingly easily, by considerably increasing the effective grinding path of the grinding tools or groups of grinding tools, compared with grinding tools which are only advanced at the rate of travel of the machine. By superimposing the additional working movement in the longitudinal direction of the track upon the continuous advancing movement of the machine, each surface area of the rail is repeatedly covered by the individual grinding tools, with the result that not only is the degree of erosion obtainable during a grinding run increased several times, but a high quality grinding result with a particular smoothing effect is also obtained.This smoothing effect is obtained not only in cases where rubbing blocks are used as the grinding tools, but also at least partly in cases where the machine is equipped with rotary grinding tools because, in this case, the formation of chatter marks is largely suppressed by the additional movement of the grinding tools relative to the rail surface.

The invention can be put into practice in several ways and with relatively simple means, particularly in the case of rail grinding machines which are equipped with their own propulsion drive and with independent power supply systems. In that case, the necessary drive mechanisms for producing the additional working movement of the grinding tools or groups of grinding tools are directly supplied by the current sources, hydraulic or pneumatic power sources present in the machine and are best centrally controlled from the driver's compartment of the machine.

In one highly practical embodiment of the invention, the grinding tool arranged on the tool frame is in the form of an endless grinding belt to which an additional, continuous working movement can be imparted; the drive mechanism may be formed by a motor, preferably a variable-speed motor, arranged on the tool frame. In addition to the advantages of multiple modifications and arrangements relative to the rail, particularly in cases where the motor is operated at high rotational speeds, this embodiment of the machine according to the invention is distinguished by its high grinding performance, by the effective adaptability of the grinding belt to the shape of the rail head and to the possibility of a relatively large treatment area and by the structural simplicity and ready replaceability of the grinding belt.

In another advantageous embodiment of the invention, at least two tool frames with groups of grinding tools formed in particular by rubbing blocks associated with a water spraying system are arranged one behind the other in the longitudinal direction of the machine, preferably for each rail, and a common drive mechanism is provided for imparting a reciprocating working movement to the two groups of grinding tools in the longitudinal direction of the machine so that they move in opposite directions. The additional reciprocating working movement of the grinding tools, particularly rubbing blocks, promotes the rapid and complete erosion not only of ridges, but also of surface faults on the rail head with a relatively large wavelength, for example of the same order as the overall length of one group of grinding tools.The opposite directions of the additional working movement imparted to the two groups of grinding tools largely prevents reaction forces from the grinding friction forces between the grinding tools, particularly the rubbing blocks, and the surface of the rail head from being transmitted to the machine frame. In addition, the common drive mechanism for paired groups of grinding tools provides for a simplified, space-saving and weight-saving structure of the machine. The described arrangement with a reciprocating working movement superimposed upon the continuous advancing movement affords particular advantages in cases where rubbing blocks are used as the grinding tools. Rubbing blocks enable the rail head, including its shoulders, to be largely restored to the original profile without any need for complicated guide and control means.Compared with rotary grinding tools, rubbing blocks can also be better adapted to curves present in the rail with the result that the guides required for laterally guiding the grinding tools around track curves can be kept very simple. It is also of advantage for the drive mechanism to be designed for synchronously driving the groups of grinding tools associated with the two rails, a drive mechanism common to both groups of grinding tools or to four groups of grinding tools associated with the two rails being provided. The synchronous drive not only provides for a consistent grinding result to be obtained during the treatment of both rails, it also prevents the generation of vibration through differences in the rhythm of movement or in the phase displacement of the working movement of the groups of grinding tools associated with the right-hand or left-hand rails.The synchronous drive is particularly advisable in cases where, as described hereinafter, the groups of grinding tools respectively arranged opposite one another are intended to be joined by crossmembers to form an integral unit.

It is of particular advantage for the common drive mechanism or mechanisms to be arranged substantially centrally between the groups of grinding tools associated with one rail or between the two rails in the central region of all the groups of grinding tools. This provides for satisfactory mass equalisation whilst keeping the arrangement substantially free from vibration.

In one particularly advantageous embodiment of the invention, the drive mechanism consists of an eccentric shaft and crank shaft or cam shaft arrangement connected to a reciprocating linkage or, optionally, of a hydraulic cylinder-and-piston arrangement, said arrangement being connected to the drive motor provided on the machine frame.

The choice of the most suitable type of drive may be made according to the projected or available basic equipment of the machine and according to other aspects, such as weight distribution and utilisation of the available space.

A satisfactory grinding result may be obtained if the overall stroke of the reciprocating working movement of the tool frame amounts to at least half, but in particular to about two thirds, of the length of the rubbing block, the frequently of the reciprocating movement of the tool frame preferably amounting to approximately 8 cycles per second. However, these values may differ considerably from those quoted, according to the application envisaged for the machine and its overall dimensions.

One particularly simple embodiment of the grinding machine according to the invention is characterised in that the tool frames, the rod and a crank shaft extending transversely of the longitudinal axis of the machine are arranged in substantially the same horizontal plane in that the crank shaft is designed to be rotated by an eccentric shaft connected to the drive motor through a crank gear and in that the tool frames of the groups of grinding tools for both rails are optionally linked individually to the crank arms of the crank shaft. This arrangement prevents the drive forces acting on the tool frame from giving rise to appreciable reaction moments in the vertical plane of the rails which could lead to differences in and periodic changes in the distribution of the contact pressure forces applied to the rubbing blocks.The described drive mechanism is also distinguished by its robustness and by the simplicity of the components used.

In another advantageous embodiment of the invention the drive mechanism provided is in the form of an eccentric shaft which is arranged with its longitudinal axis substantially vertical, optionally in the longitudinal plane of symmetry of the machine, and which is connected to the drive motor, the tool frames of the groups of grinding tools each being pivotally connected to said eccentric shaft through a connecting rod. A drive mechanism such as this is distinguished by its minimal space requirement and also by the fact that the crank arms of the eccentric shaft and the connecting rods pivotally connected thereto can be arranged just above the plane of the rail so that the moments generated by the drive forces in the tool frame assume the smallest possible value.

Particular advantages are afforded if the rotational speed of the drive motor and/or the length of the crank arms of the eccentric shaft or crank shaft is/are variable, for example in dependence upon the rate of travel of the machine. These measures enable the advancing movement and the additional working movement imparted to the grinding tools to be adapted to one another in such a way that, irrespective of the particular working conditions prevailing, the available capacity of the machine is utilised to give an optimum grinding result.

This control of the drive may also be fully automatic so that the machine operator may concentrate fully on his other tasks.

In one embodiment of the grinding machine which is particularly preferred for its structural simplicity, the tool frame consists of a longitudinal support formed, for example, by an upright sheet of metal which extends in the longitudinal direction of the machine along the rail, is flexible transversely to the machine, is connected to the machine frame for vertical adjustment and for movement in the longitudinal direction of the machine and carries individually vertically adjustable holding shoes supportable on the longitudinal support from below by way of plate springs, spacer sleeves or the like for releasably holding a rubbing block.

In this arrangement, which prevents the individual rubbing blocks from undesirably adapting themselves to the vertical trend of the rail, but which at the same time enables the rubbing blocks to be laterally adapted to the longitudinal trend of the rail by virtue of the flexibility of the longitudinal support, the rubbing blocks which are combined to form a group of grinding tools form as it were a continuous grinding body with the overall length of the group of grinding tools which is thus capable of smoothing out surface faults on the rail head whose wavelength amounts to several times the amount of an individual rubbing block or to between about two thirds and three quarters of the overall length of the group of grinding tools.

It is best suitably to interconnect the groups of grinding tools associated with the respective rails. This can be done with particular advantage by joining the longitudinal supports of the groups of grinding tools which are respectively arranged opposite one another relative to the longitudinal plane of symmetry of the machine by means of crossmembers, formed for example by upright sheets of metal, which are flexible in the longitudinal direction of the machine, are fixed to the longitudinal supports in the region of the holding shoes and are preferably adjustable in length. In addition to laterally pressing the rubbing blocks respectively arranged opposite one another onto the inner shoulder of the rail head, the flexible crossmembers also perform the function of preventing the rubbing blocks from tilting about their longitudinal axis.By means of the crossmembers, the groups of grinding tools associated with the respective rails are adapted to differences in the gauge of the track such as are encountered above all when the machine is negotiating curved sections of track.

Finally, each5 tool frame may be suspended pendulum-fashion from the machine frame by means of at least two telescopic, e.g. variable-length, guides preferably in the form of piston-and-cylinder units, and an adjusting mechanism, preferably in the form of a piston-and-cylinder unit, may be provided for the transverse adjustment of the tool frame. In this way, simple provision is made for the rubbing blocks to be pressed onto the surface of the rail head with the necessary vertical and horizontal bearing force.

Preferred embodiments of the invention are described in detail in the following with reference to the accompanying drawings, wherein: Figure 1 is a side elevation of a rail grinding machine according to the invention; Figure 2 is a plan view of the grinding tool arrangement and drive system of the machine shown in Figure 1; Figure 3 is a perspective view of a grinding tool for the machine shown in Figures 1 and 2; Figure 4 is a partial side elevation of another embodiment of a rail grinding machine according to the invention; Figure 5 is a diagrammatically simplified section on a larger scale through a grinding tool and its holder on the line V-V of Figure 4; Figure 6 is a side elevation of the grinding tool arrangement for another embodiment of a rail grinding machine according to the invention; and Figure 7 is a perspective view of a machine according to the invention equipped with rotary grinding tools.

The rail grinding machine 1 shown in Figures 1 to 3 is intended to travel continuously along the rails 4 and 5 of a laid track 6 by means of two undercarriages 2 incorporating driven wheel sets 3.

The systems by which the machine 1 is propelled, controlled and supplied with power and working fluid are arranged on the machine frame 7 which, at either end, is equipped with pull and buff couplings 8 to enable the machine 1 to be incorporated into a train formation. These systems include the drive motor 9, a compressor unit 10 with a pressure vessel 11, a water tank 12 with a valve assembly 13 and a central control unit 14 which is arranged inside the driver's compartment 15 and which comprises the arrangements necessary for operating and monitoring the machine. The drive link between the motor 9 and the two wheel sets 3, which is normally in the form of a multistage gear unit and drive shafts, is diagrammatically indicated in the drawing by dash-dot lines 16. In addition, the motor 9 is linked to the central control unit 14 through a control line 17.A compressed air line 18 extends from the pressure tank 11 of the compressor unit 10, being controllable by a valve assembly 19 which is also connected to the control unit 14 by a line 20.

The valve assembly 13 of the water tank 12 is connected to the control unit 14 through another control line 21 shown in chain lines.

For each of the rails 4 and 5, the machine 1 comprises two groups 22, 23, or 22', 23', of grinding tools which are arranged one behind the other in the longitudinal direction of the machine between the two undercarriages 2. In the embodiment illustrated, each of these groups of grinding tools consists of four grinding tools 24 in the form of rubbing blocks which are arranged one behind the other in the longitudinal direction of the rails 4 and 5 and which are mounted together for individual vertical adjustment on a tool frame 25. The tool frame 25 is in the form of a longitudinal support formed for example by an upright sheet of metal which extends longitudinally of the machine and which is relatively flexible transversely of the track 6.Each tool frame 25 is suspended pendulumfashion from the machine frame 7 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 26 which are connected to the compressed air line 18 and which are controllable by means of the valve assembly 19. The tool frame 25 is guided in the longitudinal direction of the rails 4 and 5 by means of two guide pins 28 which act on the inner shoulder 27 of the rail head.

As can be seen in particular from Figure 3, the individual substantially parallelepipedic rubbing blocks 24, of which the underneath preferably has a profile matching the required profile of the rail head 29, are each releasably fixed to a holding shoe 30 by means of screws 31. By means of a vertical guide bolt 32 arranged on its upper side, each holding shoe 30 is guided for vertical adjustment on the tool frame 25 in a bore of a guide member 33 fixed to the tool frame 25 and rests either resiliently or rigidly on the underneath of the tool frame according to the particular grinding principle selected.

Figure 3 shows an arrangement in which the holding shoe 30 is resiliently supported by means of plate springs 34, whereas Figure 1 shows an arrangement in which the holding shoe 30 is rigidly supported through spacer sleeves 35 fitted onto the guide bolts 32. To prevent the holding shoe 30 from rotating and to align the rubbing blocks 24 in the longitudinal direction of the rail, two guide lugs 36 arc arranged on the upper side of each holding shoe 30, engaging fork-like around the tool frame 25.

For cooling the rubbing blocks 24 and for flushing away the grinding dust which accumulates during the grinding operation, water spray nozzles 37 are arranged on the tool frame 25, being directed onto the spaces between the successive blocks 24. Another two water spray nozzles 37 are respectively arranged immediately in front of and behind each group of grinding tools. The spray nozzles 37 are connected to the water tank 12 by pipes shown in chain lines, the flow of water to the spray nozzles 37 being centrally controlled from the control unit 14.

In order to increase the grinding work of the rubbing blocks 24, a simultaneous, additional working movement in the longitudinal direction of the track, superimposed upon the continuous advancing movement in the direction of the arrow 38, is imparted to them 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 groups 22 and 23 of grinding tools associated with one rail, for example the rail 4, by a common drive unit 39 so that they move in opposite directions as indicated by the arrows 40 and 41. By the opposite directions of movements of the two groups 22, 23 of grinding tools, the longitudinal forces of the two groups of grinding tools caused by the friction between the rubber blocks 24 and the surface of the rail head are at least approximately compensated.

The drive unit 39 includes a crank shaft 42 which extends transversely of the longitudinal axis of the machine and which is arranged in substantially the same horizontal plane as the tool frame 25 of the groups of grinding tools. The crank shaft 42 comprises two crank arms which are offset at 1800 relative to one another and to each of which one of the two tool frames 25 is pivotally connected through a rod 43. The crank shaft 42 is arranged to be oscillated by a horizontally arranged eccentric shaft 45 connected to a drive motor 44 through a crank gear 46.By regulating the rotational speed of the drive motor 44, for example a hydraulic motor, it is possible to vary the frequency of the additional reciprocating working movement of the groups of grinding tools, for example in dependence upon the rate of advance of the machine 1, and to adapt it to mect 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, preferably to about two thirds, of the length of a single rubbing block 24. In order to be able to vary the overall stroke as and when necessary, the crank pin 47 for example may be arranged for radial adjustment on the eccentric shaft 45.

In the case of the illustrated machine 1, which is equipped with groups of grinding tools for both rails 4 and 5, the groups 22, 22' and 23, 23' of grinding tools which are respectively arranged opposite one another relative to the longitudinal plane of symmetry 48 of the machine are joined together by crossmembers 49 which are formed for example by upright sheets of metal and which are relatively flexible in the longitudinal direction of the machine, as indicated in chain lines on the left of Figure 2. The crossmembers 49, which are preferably designed for longitudinal adjustment, are fixed to the two tool frames in the vicinity of the guide members 33 of two holding shoes 30 arranged opposite one another relative to the plane of symmetry 48.By means of the crossmembers 49, the groups of grinding tools respectively arranged opposite one another are adapted to differences in the gauge of the track, above all when the machine is negotiating curved sections of track. For transversely adjusting the oppositely arranged tool frames 25, a piston-andcylinder unit 50 arranged horizontally between them is provided, being connected to the compressed air line 18 through a connecting line 51. The two piston ends of the piston-and-cylinder unit 50 are pivotally connected to brackets 52 on the opposite tool frames 25.

For fitting and replacing rubbing blocks 24 and also for when the machine 1 is in transit, the tool frames 25 are raised by means of the pneumatic piston-and-cylinder unit 26. The rubbing blocks 24 are introduced into their holding shoes 30 from below. Differences in the degree of wear of the rubbing blocks of a groups of grinding tools can be compensated by using spacer sleeves 35 of different height. The tooling of the machine may be 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 24. For example, it is possible to use rubbing blocks 24 having a lower surface which is flat to begin with and then automatically assumes the shape of the rail head after a relatively short period in grinding contact therewith. In this way, a continuously curved rail surface is obtained.

For treating the entire rail surface, including the inner shoulder 27 of the rail head, it is advisable to use rubbing blocks 24 with a preformed profile resembling a wheel flange (see Figure 5). In order to obtain a smoothing effect progressing in the direction of travel on the surface of the rail head, the groups of grinding tools may also be formed by rubbing blocks 24 of different granulometry. In addition, it is possible to graduate the contact pressure of the successive rubbing blocks 24 of each group of grinding tools in the longitudinal direction of the track.

When the tool frame 25 is lowered, the rubbing blocks 24 are pressed onto the surface of the rail head under variable pressure by means of the piston-andcylinder units 26. The laterial guiding and pressing of the rubbing blocks 24 onto the surface of the rail head is guaranteed by the flexible crossmembers 49. The drive unit 39 imparting the additional reciprocating working movement to the groups of grinding tools is started up at the same time as the drive motor of the machine.By superimposing the reciprocating working movement on the continuous advancing movement of the machine, the grinding path of each individual rubbing block 24 is at least tripled by comparison with that of a rubbing block which is only advanced at the rate of travel of the machine, as indicatedin Figure 2 by the chain line arrows 53 (amplitudes of the reciprocating working movement) by comparison with the advancing movement 38 of the machine 1.

Figure 4 shows another embodiment of a rail grinding machine 1 according to the invention of which the drive unit 54 consists of a crank shaft 56 arranged with its longitudinal axis substantially vertical and directly connected to the drive motor 55. The tool frames 25 of the groups 22, 23 of grinding tools arranged one behind the other in the longitudinal direction of the track are each connected by a connecting rod 57 to the crank arms of the crank shaft 56 offset at 1800 relative to one another. Where the machine is equipped with groups of grinding tools for both rails 4 and 5, the crank shaft 56 may be centrally arranged in the longitudinal plane of symmetry of the machine and all the groups of grinding tools may be collectively driven by the crank shaft.

In the embodiment shown in Figure 4, in contrast to the embodiments previously described, the holding shoe 30 is supported on the underneath of the tool frame 25 by means of helical springs 58.

Figure 5 shows an embodiment of a rubbing block 24 which is designed with a flange-like profile for grinding the entire level of the rail head and of which the holding shoe 30 is designed to pivot transversely of the longitudinal axis of the track in the direction of the arrows 59. To this end, the holding shoe 30 may be displaceable for example along a slot guide which follows an envelope curve of all the contact positions of the rubbing block 24 with the surface of the rail head. The holding shoe 30 is pivoted by means of a piston-and-cylinder unit 61 which is pivotally connected to an extension 60 of the holding shoe 30. The vertical and horizontal contact forces applied to the rubbing block 24 are indicated by the arrows 62 and 63.The pivotal mounting of the rubbing block 24 provides for the uniform and continuous treatment both of the surface 62 and of the shoulder 27 of the rail head 29.

Figure 6 shows an embodiment of the machine in which the grinding tool arranged on a tool frame 63 designed to be raised and lowered is in the form of an endless grinding belt 64 which is driven at a constant peripheral speed (arrows 66) by a drive motor 65). Accordingly, an addition: continuous working movement superimposed upon the advancing movement 38 of the machine is imparted to the grinding tool in the longitudinal direction of the track. This arrangement is distinguished by a high grinding performance for a relative low contact pressure of the grinding belt 64 and by a grinding result of high quality, above all at high rotational speeds of the drive motor 65.Further advantages of this construction are the fact that the grinding belt 64 can be effectively adapted to the particular profile of the rail and the fact that the grinding belt can be quickly and easily replaced.

Figure 7 shows another embodiment of the rail grinding machine of which the grinding tools are in the form of rotary grinding wheels 68 which are each driven by a motor 67 and which are arranged individually or in groups on a vertically displaceable tool frame 69 extending in the longitudinal direction of the track. A reciprocating working movement is imparted to pairs of these tool frames 69, which are arranged one behind the other in the longitudinal direction of the track, by a drive unit, for example in the manner shown in Figure 1, so that the frames of each pair move in opposite directions. The drive motors 67 with the grinding wheels 68 are connected to the tool frame 69 in such a way that they can pivot in the longitudinal direction of the track.To this end, crossmembers 70 are secured to the tool frame 69, comprising a dovetail guide for receiving a slot guide 71 with arcuate guide slots 72. Bolts 73 arranged on lateral extensions of the drive motor 67 engage in the two guide slots 72. A piston rod 75 of a piston-and-cylinder unit (not shown) is pivotally connected to an axial extension 74 of the motor 67. Accordingly, the motor 67 together with the grinding wheel 68 can be pivoted back and forth in the direction of the double arrow 76 along the curved path formed by the guide slot 72.

This provides for individual treatment of the surfaces of the rail head, particularly when several grinding wheels 68 are arranged at different angles on the same tool frame 69.

In this embodiment, too, the additional reciprocating working movement provides for an increase in the working range of each individual grinding wheel and, hence, for an increase in the grinding performance of the machine as a whole. In particular, this embodiment may even be used in combination with the rubbing blocks. For example, rotary grinding tools of the type in question may be provided at both ends of a grinding machine with rubbing blocks arranged in between.

Attention is drawn to our copending Application No. 6879/78 (Serial No.

1576193) corresponding to Austrian Patent Application A6443/77 (folio 35281), which claims 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 wheel 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 wheels, characterised in that 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.

WHAT WE CLAIM IS: I. A travelling rail grinding machine for smoothing out irregularities on the surface of the rail heads, comprising grinding tools which are mounted for vertical adjustment on the machine frame, are disposed one behind another in the longitudinal direction of the machine, are designed to be pressed onto the surface areas of the rail head to be ground, and are arranged on a tool frame, characterised in that at least one grinding tool or one group of grinding tools is equipped with a drive mechanism for imparting a simultaneous additional working movement in the longitudinal direction of the machine, superimposed upon the continuous advancing movement of the tool frame.

2. A machine as claimed in claim 1, characterised in that the grinding tool is in the form of an endless grinding belt driven, in use, by a motor arranged on the tool frame and constituting the said drive mechanism.

3. A machine as claimed in claim 2 in which the motor is a variable speed motor.

4. A machine as claimed in claim 1, characterised in that at least two tool frames with respective groups of grinding tools, are arranged one behind the other in the longitudinal direction of the machine, and in that a common drive mechanism is provided for imparting a reciprocating working movement constituting the said additional working movement to the two groups of grinding tools, in the longitudinal direction of the machine so that the groups move in opposite directions.

5. A machine as claimed in claim 4 in which the grinding tools are rubbing blocks associated with a water spraying system.

6. A machine as claimed in claim 4 or 5, characterised in that the drive mechanism is designed for synchronously driving the groups of grinding tools associated with the two rails, the drive mechanism being common to both groups of grinding tools or to four groups of grinding tools associated with the two rails.

7. A machine as claimed in claim 4, 5 or 6, characterised in that the common drive mechanism is or mechanisms are arranged substantially centrally between the two groups of grinding tools associated with one rail or between the two rails in the central region of all the groups of grinding tools.

8. A machine as claimed in any of claims 4 to 7, characterised in that the overall stroke of the reciprocating working movement of the tool frame amounts to at least half of the length of the rubbing block.

9. A machine as claimed in claim 8 in which the overall stroke is about two thirds of the length of the rubbing block.

10. A machine as claimed in claim 8 or 9 in which the frequency of the reciprocating movement of the tool frame is approximately 8 cycles/second.

11. A machine as claimed in any of claims 4 to 10, characterised in that the drive mechanism consists of an eccentric shaft and crank shaft or cam shaft arrangement connected to a reciprocating linkage or, optionally, of a hydraulic cylinder-and-piston arrangement, said arragement being connected to the drive motor provided on the machine frame.

12. A machine as claimed in claim 11, characterised in that the tool frames, the rod and a crank shaft extending transversely of the longitudinal axis of the machine are arranged in substantially the same horizontal plane, in that the crank shaft is arranged to be rotated by an eccentric shaft connected to the drive motor-through a crank gear, and in that the tool frames of the groups of grinding tools for both rails are optionally linked individually to the crank arms of the crank shaft.

13. A machine as claimed in claim 11, characterised in that the drive mechanism is in the form of an eccentric shaft which is arranged with its longitudinal axis substantially vertical, optionally in the longitudinal

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Claims

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different angles on the same tool frame 69.

In this embodiment, too, the additional reciprocating working movement provides for an increase in the working range of each individual grinding wheel and, hence, for an increase in the grinding performance of the machine as a whole. In particular, this embodiment may even be used in combination with the rubbing blocks. For example, rotary grinding tools of the type in question may be provided at both ends of a grinding machine with rubbing blocks arranged in between.

Attention is drawn to our copending Application No. 6879/78 (Serial No.

1576193) corresponding to Austrian Patent Application A6443/77 (folio 35281), which claims 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 wheel 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 wheels, characterised in that 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.

WHAT WE CLAIM IS: I. A travelling rail grinding machine for smoothing out irregularities on the surface of the rail heads, comprising grinding tools which are mounted for vertical adjustment on the machine frame, are disposed one behind another in the longitudinal direction of the machine, are designed to be pressed onto the surface areas of the rail head to be ground, and are arranged on a tool frame, characterised in that at least one grinding tool or one group of grinding tools is equipped with a drive mechanism for imparting a simultaneous additional working movement in the longitudinal direction of the machine, superimposed upon the continuous advancing movement of the tool frame.
2. A machine as claimed in claim 1, characterised in that the grinding tool is in the form of an endless grinding belt driven, in use, by a motor arranged on the tool frame and constituting the said drive mechanism.
3. A machine as claimed in claim 2 in which the motor is a variable speed motor.
4. A machine as claimed in claim 1, characterised in that at least two tool frames with respective groups of grinding tools, are arranged one behind the other in the longitudinal direction of the machine, and in that a common drive mechanism is provided for imparting a reciprocating working movement constituting the said additional working movement to the two groups of grinding tools, in the longitudinal direction of the machine so that the groups move in opposite directions.
5. A machine as claimed in claim 4 in which the grinding tools are rubbing blocks associated with a water spraying system.
6. A machine as claimed in claim 4 or 5, characterised in that the drive mechanism is designed for synchronously driving the groups of grinding tools associated with the two rails, the drive mechanism being common to both groups of grinding tools or to four groups of grinding tools associated with the two rails.
7. A machine as claimed in claim 4, 5 or 6, characterised in that the common drive mechanism is or mechanisms are arranged substantially centrally between the two groups of grinding tools associated with one rail or between the two rails in the central region of all the groups of grinding tools.
8. A machine as claimed in any of claims 4 to 7, characterised in that the overall stroke of the reciprocating working movement of the tool frame amounts to at least half of the length of the rubbing block.
9. A machine as claimed in claim 8 in which the overall stroke is about two thirds of the length of the rubbing block.
10. A machine as claimed in claim 8 or 9 in which the frequency of the reciprocating movement of the tool frame is approximately 8 cycles/second.
11. A machine as claimed in any of claims 4 to 10, characterised in that the drive mechanism consists of an eccentric shaft and crank shaft or cam shaft arrangement connected to a reciprocating linkage or, optionally, of a hydraulic cylinder-and-piston arrangement, said arragement being connected to the drive motor provided on the machine frame.
12. A machine as claimed in claim 11, characterised in that the tool frames, the rod and a crank shaft extending transversely of the longitudinal axis of the machine are arranged in substantially the same horizontal plane, in that the crank shaft is arranged to be rotated by an eccentric shaft connected to the drive motor-through a crank gear, and in that the tool frames of the groups of grinding tools for both rails are optionally linked individually to the crank arms of the crank shaft.
13. A machine as claimed in claim 11, characterised in that the drive mechanism is in the form of an eccentric shaft which is arranged with its longitudinal axis substantially vertical, optionally in the longitudinal

plane of symmetry of the machine, and which is connected to the drive motor, the tool frames of the groups of grinding tools each being pivotally connected to said eccentric shaft through a connecting rod.
14. A machine as claimed in claim 2, 11, 12 or 13, characterised in that the rotational speed of the drive motor and/or the length of the crank arms of the eccentric shaft or crank shaft is/are variable, for example in dependence upon the rate of travel of the machine.
15. A machine as claimed in any of claims 1 to 14, characterised in that the tool frame consists of a longitudinal support which extends in the longitudinal direction of the machine along the rail, is flexible transversely of the machine, is connected to the machine frame for vertical adjustment and for movement in the longitudinal direction of the machine and carries individual vertically adjustable holding shoes supportable on the longitudinal support from below by way of plate springs, spacer sleeves or the like for releasably holding a rubbing block.
16. A machine as claimed in claim 15 in which the longitudinal support is an upright sheet of metal.
17. A machine as claimed in claim 15 or 16, characterisedin that the longitudinal supports of the groups of grinding tools which are respectively arranged opposite one another relative to the longitudinal plane of symmetry of the machine are joined by crossmembers, which are flexible in the longitudinal direction of the machine, are fixed to the longitudinal supports in the region of the holding shoes.
18. A machine as claimed in claim 17 in which the crossmembers are upright sheets of metal.
19. A machine as claimed in claim 17 or 18 in which the cross members are adjustable in length.
20. A machine as claimed in claim 15, 16 or 17, characterised in that each tool frame is suspended pendulum-fashion from the machine frame by means of at least two telescopic, i.e. variable-length, guides and and adjusting mechanism, is provided for the transverse adjustment of the tool frame.
21. A machine as claimed in claim 20 in which the guides are piston and cylinder units.
22. A machine as claimed in claim 20 or 21 in which the adjusting mechanism is a piston and cylinder unit.
23. A rail-grinding machine substantially as herein described with reference to figures 1 to 3, Figures 4 and 5, Figure 6 or Figure 7 of the accompanying drawings.