GB2121710A - A device for milling rail heads of railway tracks - Google Patents

Abstract

The in-situ milling of rail heads of rails 14 is effected by a device having at least one driven rotating milling head (2) with at least one milling cutter head drive (3) mounted on a bogie frame 16 which has guide shoes (4) which can be selectively raised and lowered and are arranged ahead of and behind the milling head (2) with of reference to the direction of travel. Lateral guide rollers (5) are provided which engage the side of the rail head (15) of a rail (14) to be machined. The milling cutter head (2) may have as many cutting edges or tools (21,22,23,24) (not shown) as the number of partial arcs to be milled and two milling units each having a milling head (2) and a milling head drive (3) can be provided for the simultaneous machining of the two rails (14) the two milling cutter housings (1) being connected to one another by means of (6) with gauge tolerance adjusting means (7, 20). The milling cutter housings may be arranged on pivotal supports (25, 26) connected to a swivel beam or bar (11) of a bogie (17) by way of link pins (12). The device can be in the form of a self-propelled unit or a unit which is drawn, by a locomotive.

Description

SPECIFICATION A device for milling rail heads The invention relates to a device for milling the heads of rails of tracks laid on a ballast bed, the device comprising at least one rotating milling head in a running gear containing at least one milling drive.

The rails, particularly of railway lines, become worn after a relatively long operating time owing to the fact that deformations and wear occur on the rail head which can lead, for example, to prominences and indentations (chatter marks) alternating in the direction of travel.

Displaced materials and signs of wear also appear on the rounded-off section facing the wheel flange of the wheels of the vehicles running over the rails and between the ends of adjoining lengths of the rails. It is therefore necessary to re-machine at appropriate intervals of time.

Re-machining can br effected, for example, by planing. In this technique a planing device is driven over the rails and the profile of the rail head is restored with the aid of the planing tool.

However, it has been found that the planing of rails can lead to interruptions in track operation since the occurrence, for example, of long shavings can disturb safeguarding or protective systems which are arranged on or beside the rails. Also, persons within a station area may be endangered by flying shavings or fragments. The force acts only in the forward or feed direction so that normally a plurality of successive planing operations are necessitated on the same rail in order to restore the necessary profile.

Rail or track grinding which is still also practised, has the crucial disadvantage that chip removal is only small so that a considerable working time is necessitated in order to achieve the required restoration of the rail head profile.

The milling of rail heads has, on the other hand, proved very successful. Previously, the rails were actually removed from the track ballast and machined in fixed installations, each of the rails preferably having been drawn past fixed milling stations. Moreover, it is also known practice to move, in the relevant works, a milling station in a travelling crab or similar transfer devices relative to fixed rails.

It has already been proposed, as in Swiss Patent Specification No. 381 055, to machine rails of a railway truck, laid on ballast, in such a manner that a wagon carrying the milling heads is guided along the rail itself or along a plurality of parallel workpieces arranged side by side. However, Swiss Patent Specification 381 055 provides no information as to how a wagon of this type can be designed in order to enable the milling of laid railway lines to be carried out.

The present invention therefore seeks to provide a device with which tracks laid in ballast can be re-machined in situ, i.e. the necessary profile of the rail heads can be restored in a simple manner and at a low cost, even on bends.

According to the invention, there is provided a device for the milling of rail heads of rails of tracks laid on a ballast bed said device comprising at least one rotating milling head in a running gear containing at least one milling head drive, wherein the device includes a lifting cylinder which is mounted in a bogie truck frame to absorb the cutting forces, guide shoes which are arranged ahead of and behind the or each milling head with reference to the direction of travel and which can be selectively raised and lowered, and lateral guide or contact rollers which engage on the rail head of a rail to be machined.

The design of a rail head milling device in accordance with the invention makes it possible for the required cutting pressure or load to be constantly applied in order to prevent the milling head from sliding along the rail head without any cutting action. It is ensure that, when in the cornering position, the bogie is not raised and that the necessary profile can be machined at the desired milling speed.

It is particularly useful if a milling cutter housing having a milling head is arranged so as to be height-adjustable relative to the guide shoe, and if an eccentric device is provided for height adjustment. This feature enables very accurate adaptation to the working conditions in each case.

It has been found particularly useful if a hydraulic motor is provided as the drive motor for the milling head. The supply means for the working medium of this motor can be advantageously mounted without difficulty on the bogie frame. To machine the cross-section profile of the rail heads, which consists of circular arcs of different radii, it is advantageous if the milling head comprises a set of straight milling head cutting edges which are arranged in a specific direction relative to the axis, with as many cutting edges being provided as the number of partial arcs to be milled.

In accordance with a preferred embodiment of the invention interchangeable reversible carbide tips are provided as the cutters.

In a further advantageous embodiment of the invention, two milling units having a milling cutter head and a milling head drive are provided for the simultaneous machining of each of the two rails of a track or line, and the two milling cutter housings are connected to one another by means of milling cutter housing supports incorporating gauge tolerance adjusting means.

This adjustability of the two milling units relative to one another ensures that, even in the case of wheel or track gauge variations the milling heads each come exactly into contact with their associated rail heads so that precise machining can be carried out, particularly on the inner profiled parts of the rail heads, irrespective of relative differences in level between the two tracks and irrespective of relative variations in gauge or clearance.

When tracks are laid it is necessary to perform the appropriate machining operations on the rail heads, even on bends. For this purpose it is advantageous if the milling cutter housings are mounted on supports, the supports being attached to a pivotal beam or bar of the bogie by way of link pins. This makes it possible, when travelling through bends with the milling cutter effectively moving along the chord of the arc, that the milling units can always become operative on their associated rails, even in the event of cant or elevation of each rail.

The device according the the invention can be designed in accordance with an advantageous embodiment in such a manner that the bogie is in the form of an attachable or hitchable self-propelled unit, the drive or braking being affected by a traction engine. In a further development of the invention, it is advantageous if the bogie is provided with its own motor for driving the travelling gear. As a result so-called "climb-milling" can be performed, just as it can be performed in the case of a drawn unit.

In accordance with a particularly advantageous embodiment of the invention, the bogie is part of a self-propelled locomotive and the milling unit is arranged approximately in the longitudinal centre of the locomotive. This makes it possible for the propelling means or the locomotive to be used to apply the cutting pressure, the weight of the drive replacing the otherwise necessary ballast.

An embodiment of the invention will now be described in more detail by way of example and with reference to the accompanying drawings in which: Figure 1 shows, in diagrammatic form, a longitudinal side view of a device according to the invention.

Figure 2 shows a front view of the device shown in Fig.1.

Figure 3 shows a diagrammatic plan view of the device of Figs. 1 and 2, and Figure 4 shows a diagram of the arrangement of cutting elements on a milling head.

In the embodiment of a track milling device shown in Figs. 1 to 3, the device is mounted on a bogie frame 1 6 of a bogie or vehicle 1 7 having wheels 1 8 on alternate sides or arranged in pairs. A milling unit consists of a milling cutter housing 1 in which there is arranged a multitrack milling head 2 which is driven by a milling head drive motor 3 via appropriate driving means.Height-adjustable guide shoes 4, which under certain operating conditions rest on or are supported on a rail head 1 5 of a rail 14 of a track laid on a ballast bed, are provided ahead of and behind the milling unit with reference to the direction of travel indicated by the arrow A". In addition, guide or contact rollers 5, which are applied or pressed correspondingly against each rail head 15, are provided laterally of the milling head 2 or the side of the guide shoes 4. A cutting depth adjuster 8, which cooperates with a cutting depth eccentric adjuster 9 and which can be operated by means of a cylinder 19, serves to adjust the height of the guide shoes 4 relative to the milling head 2 whereby the depth of cut can be adjusted.

The cylinder 1 9 is pivotable mounted on a bracket 27 of the milling cutter housing 1.

Engaging on the bogie frame 1 6 is a lifting cylinder 10 which serves to apply the cutting pressure and which, in normal operation, i.e.

when the rails are not being machined, lifts the milling unit clear of the rail. In this connection, preferably a piston rod 29 engages on a support-in plate 28 of the milling cutter housing 1.

As can be seen on the left of Fig. 1 and as is explained in more detail in connection with Fig. 3, the milling unit is mounted on a support 25 or 26 which is connected to a pivotal beam or bar 11 of the vehicle frame by way of link pins 1 2. This makes it possible for the milling unit always to engage on or rest on the associated rail, even when travelling through bends, when the travelling or running gear 17, 18, actually moves along a chord relative to the bend.

As will be explained in even greater detail in connection with Fig. 4, the multitrack milling head 2 has a plurality of juxtaposed straight cutting elements which are adapted to the outline of the rail head 1 5 and which enable the entire outline to be machined in a single working cycle. The design of the gauge tolerance adjusting means 7 in particular can be seen from Fig. 2, brackets 30 on a milling cutter housing support 6 being connected in each case to the gauge tolerance adjusting means 7 by swivel arms 31.

As can be seen from Fig. 3, these gauge tolerance adjusting means 7 advantageously comprise a cylinder 20 which normally forces the two milling units uniformly to the right and left relative to the longitudinal axis of the track. This makes it possible for each of the inner lateral guide rollers 5 to be pressed firmly against the rail 14 or rail head 1 5. It can be seen from Fig. 3 that two milling units are provided for the simultaneous machining of two rail heads 15, the said units, as already mentioned, being pivotable connected to the swivel beam or bar 11 by supports 25 and 26 and link pins 1 2. The co-operation of the lateral guide rollers 5 with the cylinder 20 and the swivel arms 25, 26 results in reliable guidance of the milling units, even in the event of gauge tolerances and when travelling through bends.

Fig. 4 shows a diagrammatic view of the geometric arrangement of milling head cutters 21, 22, 23 and 24 which are adapted to the respective arcs 21', 22' 23' and 24' of a rail head 15. In this case the cutters 21 and 22 and preferably in the form of reversible carbide tips and are clamped firmly in the milling head 2.

The cutters 23, 24 can be in the form of soldered profile cutters, the shanks of which are also clamped in the milling head 2, thereby enabling easy replacement of the metal-cutting tools and easy adaptability to different prifle shapes of rails 14 or rail heads 15.

A track milling device according to the invention operates essentially in the following manner: When travelling to the place of use, as will be understood, the entire milling unit is lifted clear of the rail 14, for example by approximately 1 50 mm, by means of the lifting cylinder 10. When milling on a straight length of track, with the milling taking place in the direction of arrow A in Fig. 1, the milling unit is lowered on to the rail 14 by means of the lifting cylinder 10. With the aid of the cylinder 1 9 for the cutting depth eccentric adjuster 9 which is in the extended position, the righthand guide show 4 as shown in Fig. 1, is brought into line with the milling head 2, no material having been removed at this stage.

The other or left-hand guide shoe 4 seen in Fig. 1 is spring-mounted with respect to the rail 14. With the aid of the cylinder 20 for the gauge tolerance adjuster 7, the milling units are forced apart from one another until the inner lateral guide rollers 5 engage the rails thereby compensating for gauge tolerances.

By way of the milling cutter housing support 6 and the gauge tolerance adjuster 7, the milling cutter housing 1 is supported on the oppositely lying guide shoe 4 to prevent tilting forces. The guide shoes 4 are also used to damp vibrations.

The milling operation is first initiated by lowering the milling unit slowly to the appropriate cutting depth on a rail several meters long. This is effected by moving the cutting depth eccentric adjuster by means of the cylinder 1 9 to a preset depth of cut with the aid of the device 8. The spring-mounted (lefthand) guide shoe 4 moves up accordingly and the milling operation can commence and can be performed with the desired or required depth of cut over the length of each rail to be machined.

It is also possible for only one rail of a track to be milled. In this case, however, the inoperative milling unit is lifted clear by the associated eccentric device 9, 1 9.

When milling on bends, the link pins mounted on the pivoted or swivel beam or bar 11 make it possible for the support 25, 26 of each milling unit constantly to follow the arc of the track and to bear against each of the rails 14 or rail heads 15 to be machined.

The bogie frame 1 6 can be part of a drawn bogie or it can alternatively even be part of a self-propelled vehicle frame 1 7. For this purpose it is possible to use driving means which are known per se and which are therefore not shown. Moreover, the unit can be designed as a self-propelled unit in the form of a locomotive which bears the driving means for the running gear, the means of supply for the milling head drive motor and for operating the lifting cylinders and other adjusting means.

Claims (11)

1. A device for milling rail heads of rails of tracks laid on a ballast bed, said device comprising at least one rotating milling head in a running gear containing at least one milling head drive, wherein the device includes a lifting cylinder which is mounted in a bogie truck frame to asbsorb the cutting forces, guide shoes which are arranged ahead of and behind the or each milling head with reference to the direction of travel and which can be selectively raised and lowered, and lateral guide or contact rollers which engage on the rail head of a rail to be machined.

2. A device according to claim 1, wherein a milling cutter housing having a milling head is arranged so as to be height-adjustable relative to the guide shoes and an eccentric device is provided for height adjustment.

3. A device according to claim 1 or claim 2, wherein a hydraulic motor is provided as the drive motor for the or each milling head.

4. A device according to any one of the preceding claims, wherein the or each milling cutter head comprises a set of straight milling head cutting edges for milling the rail heads, the profile of which consists of circular arcs having different radii, the or each milling head having the same number of cutting edges as the number of partial arcs to be milled.

5. A device according to any one of the preceding claims, wherein interchangeable reversible carbide tips are provided as the cutters of the or each milling head.

6. A device according to any one of the preceding claims, wherein two milling units having a milling cutter head and a milling head drive are provided for the simultaneous machining of the two rails of a track or line, and the two milling cutter housings are connected to one another by means of milling cutter housing supports through gauge tolerance adjusting means.

7. A device according to claim 6, wherein the milling cutter housings are mounted on supports, and the supports are arranged on a pivotal or swivel beam or bar of a bogie by link pins.

8. A device according to any one of claims 1 to 7, wherein the said device is built into a bogie frame which is moved by a traction engine or locomotive.

9. A device according to claim 7, wherein the bogie is provided with its own motor for driving the travelling gear.

10. A device according to any one of claims 1 to 7, wherein the bogie is part of a self-propelled locomotive and the milling unit is arranged approximately in the longitudinal centre of the locomotive.

11. A device for milling the rail heads of rails of tracks laid on a ballast bed, substantially as hereinbefore described, with reference to the accompanying drawings.