GB1565900A

GB1565900A - Travelling machine for measuring and/or correcting the level of a railway track

Info

Publication number: GB1565900A
Application number: GB5228977A
Authority: GB
Original assignee: Franz Plasser Bahnbaumaschinen Industrie GmbH
Current assignee: Franz Plasser Bahnbaumaschinen Industrie GmbH
Priority date: 1976-12-15
Filing date: 1977-12-15
Publication date: 1980-04-23
Also published as: DE2737976A1; FR2374472B1; AT350611B; DE2737976C2; FR2374472A1; ATA928376A

Description

(54) A TRAVELLING MACHINE FOR MEASURING AND/OR CORRECTING THE LEVEL OF A RAILWAY TRACK (71) We, FRANZ PLASSER BAHNBAUMASCHINEN INDUSTRIE GESELLSCHAFT, mbH of Johannesgasse 3, Vienna, 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 machine for measuring and/or correcting the level of a railway track, comprising a levelling reference system, which consists of a gradient beam arranged on the machine in the rear, corrected section of track and of a levelling reference line arranged in the uncorrected section of track and connected at its rear end to the gradient beam, and means for measuring the vertical distance between the levelling reference line and the track in the vicinity of the level-correcting tools.

Levelling reference systems for use in conjunction with machines for measuring and correcting the level of a railway track are already known in a variety of different forms. They are either set up stationarily at regular intervals (British Patent Specification No. 886,230) or are moved together with the machine (British Patent Specification No. 970716).

The present invention relates in particular to machines comprising a levelling reference system of the mobile type which is provided with three datum points arranged one after the other in the longitudinal direction of the track. In machines of this type, a reference line formed by a wire or a light beam extends between a front datum point and a rear datum point, the track being raised to the level of this reference line in the vicinity of the intermediate datum point, which lies closer to the rear end than to the front end of the reference line.Depending upon the distance selected between the intermediate datum point and the rear datum point in relation to the overall length of the reference line, it is possible to obtain a corresponding reduction in the track level errors which are present at the front datum point and which represent a deviation in the level of the existing track from the prescribed position of the track. In this way, the track is moved, in the vicinity of the intermediate datum point, to a level which is incorrect by the size of this track error multiplied by the error reduction ratio.Above all, however, in cases where levelling reference systems of this type are used over periodic track errors, i.e. in undulating sections of track, the reaction of the track error both from the front end and also from the rear end of the levelling reference system gives rise to a new undulating track position of which the amplitude is at best generally lower than that of the original undulating track position and which is characterised by a phase shift, the behaviour of the levelling reference system differing according to the wave length of the track errors.On account of the shortness of the levelling reference system (shorter than the wavelength) attributable to the construction of the machine and to the possibilities of practical application, the long waves in the track cannot be recognised as track errors and corrected, instead the levelling reference system follows these waves without influencing them. One disadvantage of this is that, particularly at high speeds of travel, the undulating level of the track gives rise to considerable vehicle motion which in turn results in excitation in the natural frequency of the carriage, i.e. in resonance phenomena, which adversely affect the smoothness of the vehicles in travel.

The object of the present invention is to provide a machine having a levelling reference system of the type referred to above which provides for greater error reduction and also for the adaptation thereof to different sections of track, such as straight sections, curves and the like, and by which it is possible to obtain greater accuracy in the measurement and/or correction of level errors, particularly for recognising and correcting undulating track errors of various wavelengths which are greater than the length of the reference system, without at the same time significantly altering-the existing overall length of the machines and the mobile levelling reference system.

According to the invention, there is provided a travelling machine for measuring and/or correcting the level of a railway track, comprising a levelling reference system, which consists of a gradient beam arranged on the machine in the rear, corrected section of track and extending in the longitudinal direction of the track, and of a levelling reference line extending over the uncorrected section of track and connected at its rear end to the gradient beam, and means for measuring the vertical distance between the levelling reference line and the track in the vicinity of the correcting tools, characterised in that the point at which the rear end of the levelling reference line is connected to the gradient beam is adjustable in the longitudinal direction of the track, to change the track level error reduction ratio, and in that the gradient beam is connected to an adjusting drive and to a means for monitoring the longitudinal direction of the gradient beam and controlling said direction so that it has a predetermined relation to the prescribed longitudinal gradient of the track.

By virtue of the construction of the levelling reference system, it is possible to adapt the error reduction ratio to track errors having different wave-lengths and, above all, to track errors of which the wavelength is greater than the length of the levelling reference system used, and also to detect and/or correct track errors such as these, without at the same time having to alter the overall structure and particularly the length of machines of the type in question for measuring and/or correcting the level of a track. At the same time, the particular change required in the error reduction ratio may be obtained with relatively simple means, in addition to which negative effects from the rear end of the levelling reference system is guided according to the prescribed longitudinal gradient of the track, preferably parallel to it.Also, the error reduction ratio and, by virtue of the fact that the track is now raised more closely to the absolute prescribed position, the accuracy of the level correction, are advantageously increased without any change in the existing overall lengths of mobile levelling reference systems which provide for a clearly visible construction and for correct use of the machines in practice. For example, for an overall length of the reference system of 24 metres and with a reduction in the distance between the instrument for measuring the vertical distance and the rear end of the levelling reference system from 4 metres to 1 metre, the reduction ratio can be increased from 1:6 to 1:24.By virtue of these various possibilities for adapting the error reduction ratio, the remaining deviations in the level or longitudinal level from a prescribed position can be minimised so that the angle of inclination of the downwardly sloping section of track into a track depression is flatter and, above all, the amplitude of longwave track depressions, which amount to a multiple of the overall length of the levelling reference system, is reduced. In addition, even if the track depressions cannot be completely raised to an absolute horizontal, it is possible to create a balanced and drawn-out transition, thereby preventing the development of resonance vibrations and, hence, increasing the smoothness of the carriages in travel, even in the case of high-speed trains.At the same time, however, the use of the front end of the levelling reference system which is situated in the uncorrected section of track ensures that, even in the case of extremely long track depressions attributable to the track plan, the reference line follows these changes in the track and uncontrolled lifting of the track and, in particular, kinks in the corrected track can be avoided.

In addition, it is best for the length of the mobile levelling reference system to be selected to correspond to that of existing machines so that existing machines may be refitted very simply and inexpensively. In this connection, it is also possible above all to use the supporting points already present in the machine in the construction of the levelling reference system designed in accordance with the invention.

Preferably, the connecting point of the rear end of the wire levelling reference line which, together with the gradient beam, forms a mobile levelling reference system, is situated at the front end of the gradient beam. This enables the levelling reference line and the gradient beam to extend beside one another or one within the other, particularly in the vicinity of the rear end of the reference system, and hence enable space to be saved in the operator's cabin. In addition, this arrangement provides for clear access to the connecting points between the reference line and the gradient beam, thereby facilitating the adjusting operations.

It is possible to provide the gradient beam with receiving bores arranged at intervals from one another in the longitudinal direction of the machine for receiving a locking bolt which forms the rear end of the wire levelling reference line. This embodiment is distinguished in particular by iits simple construction and by the possibility which it affords for the rapid, at-a-glance adjustment and exact fixing of the rear end point.

It has also proved to be of particular advantage to connect the means for monitoring and controlling the longitudinal direction of the gradient beam to a transmitter responsive to the position of a pendulum mounted substantially centrally on the gradient beam. In this way, the longitudinal direction of the gradient beam may be directly adjusted on the basis of the gradient values shown on the track plans or displayed along the section of track, so that the rear end of the reference line is guided exactly, thereby avoiding adverse effects upon the track measuring and/or correcting operation in the vicinity of the distance measuring unit.

It has also proved to be of particular advantage for the gradient beam to be guided on the track through two supports in the corrected section of track and for at least one support of the gradient beam.

preferably that which is adjacent to the height-measuring unit, to be made in two parts for length variation, the upper part connected to the gradient beam being in the form of a threaded spindle which is driven through a motor, for example a hydraulic or electric motor, and which is mounted for adjustment in a guide block secured to the lower part of the support, and for the connection between the lower part and the guide block or between the threaded spindle and the motor to be in the form of a joint, for example a universal joint or the like. This embodiment is distinguished in particular by the combination of the high accuracy in adjusting operations which it is possible to obtain with threaded spindles and the high rate of readjustment provided by the highspeed electric or hydraulic motors.In this way, both the time required for the readjustment and also the tolerances in the mechanical transmission can be kept to a minimum, as a result of which exact readjustment is guaranteed even at high work rates.

In another advantageous embodiment of the invention, the pendulum, pivotally mounted on the gradient beam in the longitudinal direction thereof about an axis directed transversely of the beam, comprises a pendulum rod fixedly connected to a feeler arm extending longitudinally of the track, and the feeler arm is provided with an extension extending into the vicinity of an electromagnet which is arranged on the gradient beam and which attracts transversely of the longitudinal axis thereof. In this way, the pendulum rod is isolated from the longitudinal accelerations accompanying the acceleration and deceleration of a machine as it advances in steps, so that the actual longitudinal direction of the gradient beam can be exactly measured, taking its prescribed direction into account, immediately after the machine has stopped.

The transmitter responsive to the pendulum may be formed by two momentary-contact switches which are mounted at a vertical distance apart from one another in particular on an intermediate support, and which can be adjusted together at their distance from the gradient beam through a vertical adjusting mechanism cooperating with an indicating scale. This facilitates adaptation of the longitudinal direction of the gradient beam to different prescribed gradients because the horizontal position of the pendulum may be used in each case so that, by reference to the vertical setting of the momentary-contact switches by means of the vertical adjusting mechanism and the indicating scale, gradients deviating from the horizontal can also be monitored and corrected.

In the interests of better understanding, the invention is described in more detail in the following with reference to the embodiments shown by way of example in the accompanying drawings, wherein: Figure 1 is a diagrammatic side elevation of a track maintenance machine with a mobile levelling reference system consisting of a gradient beam and a levelling reference line, with the variations in level of the track shown on an exaggerated scale over the length of the levelling reference system, Figure 2 is a side elevation drawn on a larger scale of a variaiit of the arrangement and structure of the monitoring and control system associated with the gradient beam, and Figure 3 is another diagrammatic side elevation showing for comparison a levelling reference system according to the present invention and a conventional levelling reference system on a section of track having a low region of which the length is greater than the length of the reference system, the same reference numerals being used for corresponding parts in Figures 2 and 3.

Figure 1 shows a track tamping and levelling machine 2 for measuring and correcting the level of a railway track 1 consisting of rails and sleepers, which machine, in operation, advances on the rails in the direction of the arrow A, and is provided with a levelling reference system 3 and correcting tools 36, in the form of lifting and tamping tools, for correcting the level of the track. The levelling reference system 3 consists of a gradient beam 4 and of a levelling reference line 6 which is formed by a taut wire 5 and with which is associated a measuring unit 7 for measuring the vertical distance between the levelling reference line 6 and the track in the vicinity of the correcting tools. The gradient beam 4 is located on the track 1 through two supports 8, 9 independently of vertical movements of the chassis of the machine 2.Similarly, a front end point 10 of the levelling reference line 6 is located on the track 1 through a support 11. A rear end point 12 of the levelling reference line 6 is mounted on the gradient beam 4. The measuring unit 7 is also located on the track independently of the machine chassis and comprises a transducer in the form of a rotary potentiometer or a synchrogenerator actuated by a sensing fork which embraces the wire 5.

The longitudinal section of track shown in Figure 1 consists of the correction zone 13 situated in the vicinity of the correcting tools 36 (lifting tools and tamping tools), the uncorrected section of track 14 extending forwards from this correction zone, and the corrected section of track 15 extending rearwards from this correction zone.

Whereas the front end point 10 of the reference line 6 in the uncorrected section of track 14 and the front end of the wire 5 is secured to the chassis of the machine, for example with a tensioning element, for example a spring, the effective length of the levelling reference line 6 in the corrected section of track 15 is limited by the rear end point 12 which can be fixed on the gradient beam 4 at different positions to provide a required error reduction ratio; a locking bolt 16, which receives the rear end point 12 of the wire levelling reference line 6, can be inserted into any of the receiving bores 17 formed at intervals along the gradient beam 4.

In addition, an arrangement 18 for monitoring and automatically controlling the longitudinal direction of the gradient beam is fixed to the gradient beam 4, being connected through the control lines to an adjusting drive 19 for adjusting the gradient beam 4. In the illustrated case, the arrangement 18 is formed by a pendulum 20 with a position transmitter 21 and a control unit 22 associated therewith for controlling the drive 19.

In Figure 2, the arrangement 18 for monitoring and controlling the longitudinal direction of the gradient beam is again formed by a pendulum 23 which is mounted to pivot about an axis 24 arranged on the gradient beam and extending transversely to its longitudinal direction. A feeler arm 26 is fixedly connected to the pendulum rod 25.

In addition, an electromagnet 27 is arranged on the gradient beam 4, attracting transversely to the longitudinal direction of the beam and co-operating with an extension 28 fixed to the arm 26. The transmitter 21 associated with the pendulum 23 is formed by two momentary-contact sensing switches 29, arranged on an intermediate support 30 which is provided with a mark for co-operation with an indicating scale 31 and which is adjustable in its distance from the gradient beam 4 by means of a vertical adjusting mechanism 32 consisting of a spindle and travelling nut assembly.

The support 9 of the gradient beam 4 is made in two parts for the purposes of vertical adjustment and for varying the longitudinal direction of the gradient beam, the upper part connected to the gradient beam 4 being in the form of a threaded spindle 33 which can be driven by a motor, for example a hydraulic or electric motor. A guide block 34 secured to the lower part of the support 9 receives the threaded spindle 33, the connection between the lower part of the support 9 and the guide block 34 being in the form of a universal joint, for example a Cardan joint. Alternatively, the universal joint may be arranged between the drive motor and the threaded spindle 33.

In the interests of a better understanding of the function of the levelling reference system 3 according to the invention, Figure 3 shows a section of track having a dip longer than the levelling reference system 3 which has the length L, extending between the points A and C. In a conventional mobile levelling reference system, a reference line 35 (dash-dot line) extends from point A to point C, i.e. from the uncorrected section of track 14 into the corrected section of track 15. At point B, in the correction zone 13, an approximate correction value h is determined by means of the measuring unit 7. If the track is raised by this approximate value h, it is then situated in the dash-dot position. on the basis of the error reduction ratio L1, X1, (X, being the distance AB), the track error v present in the uncorrected section of track 14 is merely reduced to the value y.X,/L,.

When the levelling reference system according to the invention is used, the distance between the rear end point 12 of the wire levelling reference line 6 and the measuring unit 7 is reduced to the distance X between the points E (below point 12) and B. In this way, the error reduction ratio L/X is considerably increased, so that an approximate correction value H greater than h is obtained and its correction leaves only a minor residual error of level Af equal to y. X/L. As shown by the position of the track after it has been raised by the value H, shown in thin, solid lines, the corrected track position follows the dip in the track much more slowly, by virtue of the increase in the error reduction ratio, with the result that in overall terms the level of the track is corrected to a considerable extent over a relatively long section of track.A defective position of the rear end point 12 of the reference line 6 is avoided by exact adjustment of the longitudinal direction of the gradient beam in accordance with the required gradient of the track.

In the case of the arrangement shown in Figure 1, this adjustment is effected by means of a for example hydraulically damped pendulum 20 of which the swing is detected by the transmitter 21 and delivered to the control unit 22. The control unit 22 activates the adjustment drive 19 accordingly to tilt the gradient beam 4 until the required inclination or longitudinal direction of the beam is reached. In order to isolate the pendulum from the accelerations occurring in the longitudinal direction of the track, the pendulum 20 may be blocked, as in Figure 2, by an electromagnet during the advancing movements of the machine.

Gradients deviating from the horizontal may be preselected electrically by means of digital or analog adjusting elements through the control unit 22.

In the arrangement shown in Figure 2, the horizontal position of the arm 26 is used for adjusting the longitudinal direction of the gradient beam. Any deviations from the horizontal that may be required are effected by vertically adjusting the intermediate support 30 by means of the vertical adjusting mechanism 32 in conjunction with the indicating scale 31. In this way, the two switches 29 are adjusted in their vertical position relative to the gradient beam 4 in such a way that, when the arm 26 is in the horizontal position, the gradient beam assumes the required inclination.The inclination of the gradient beam is readjusted by means of the arm 26 which, in the event of a deviation of the gradient beam from the required direction, actuates one of the two switches 29 and, for example makes the circuit to the electric motor of the threaded spindle 33 which is thus rotated until the arm 26 is no longer in contact with either of the two switches 29.

Accordingly, the control system in question is an automatic control system.

As can be seen from Figure 2, the wire 5 may extend through the gradient beam, which is in the form of a tube, into the region of the rear support 8 of the gradient beam 4. In this case, the interval X shown in Figure 3, for which there are numerous possibilities of adjustment, and the point E may be fixed by inserting locking bolts 16 into the receiving bores 17 distributed over the length of the gradient beam 4. However, it is of course also possible to replace this step-by-step adjustment by means of locking bolts with a continuous adjustment drive, for example a hydraulic multistage cylinderand-piston assembly or a clamping mechanism which can be continuously shifted along the gradient beam.

WHAT WE CLAIM IS: 1. A travelling machine for measuring and/or correcting the level of a railway track, comprising a levelling reference system, which consists of a gradient beam arranged on the machine in the rear, corrected section of track and extending in the longitudinal direction of the track, and of a levelling reference line extending over the uncorrected section of track and connected at its rear end to the gradient beam, and means for measuring the vertical distance between the levelling reference line and the track in the vicinity of the correcting tools, characterised in that the point at which the rear end of the levelling reference line is connected to the gradient beam is adjustable in the longitudinal direction of the track, to change the track level error reduction ratio, and in that the gradient beam is connected to an adjusting drive and to a means for monitoring the longitudinal direction of the gradient beam and controlling said direction so that it has a predetermined relation to the prescribed longitudinal gradient of the track.

2. A machine as claimed in claim I in which the reference line comprises a taut wire.

3. A machine as claimed in Claim 1 or 2, characterised in that the connecting point of the rear end of the levelling reference line which, together with the gradient beam, forms a mobile levelling reference system, is situated in the front end region of the gradient beam.

4. A machine as claimed in Claim 1, 2 or 3 characterised in that the gradient beam is provided with receiving bores arranged at intervals from one another in the longitudinal direction of the machine for receiving a locking bolt which defines the rear end of the wire levelling reference line.

5. A machine as claimed in any of Claims 1 to 4, characterised in that the gradient beam is guided on the track through two supports in the corrected section of track and in that at least one support of the gradient beam is made in two parts for length variation, the upper part, connected to the gradient beam, being in the form of a threaded spindle which is driven through a motor, for example a hydraulic or electric motor, and which is mounted for adjustment in a guide block

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. shown in thin, solid lines, the corrected track position follows the dip in the track much more slowly, by virtue of the increase in the error reduction ratio, with the result that in overall terms the level of the track is corrected to a considerable extent over a relatively long section of track. A defective position of the rear end point 12 of the reference line 6 is avoided by exact adjustment of the longitudinal direction of the gradient beam in accordance with the required gradient of the track. In the case of the arrangement shown in Figure 1, this adjustment is effected by means of a for example hydraulically damped pendulum 20 of which the swing is detected by the transmitter 21 and delivered to the control unit 22. The control unit 22 activates the adjustment drive 19 accordingly to tilt the gradient beam 4 until the required inclination or longitudinal direction of the beam is reached. In order to isolate the pendulum from the accelerations occurring in the longitudinal direction of the track, the pendulum 20 may be blocked, as in Figure 2, by an electromagnet during the advancing movements of the machine. Gradients deviating from the horizontal may be preselected electrically by means of digital or analog adjusting elements through the control unit 22. In the arrangement shown in Figure 2, the horizontal position of the arm 26 is used for adjusting the longitudinal direction of the gradient beam. Any deviations from the horizontal that may be required are effected by vertically adjusting the intermediate support 30 by means of the vertical adjusting mechanism 32 in conjunction with the indicating scale 31. In this way, the two switches 29 are adjusted in their vertical position relative to the gradient beam 4 in such a way that, when the arm 26 is in the horizontal position, the gradient beam assumes the required inclination.The inclination of the gradient beam is readjusted by means of the arm 26 which, in the event of a deviation of the gradient beam from the required direction, actuates one of the two switches 29 and, for example makes the circuit to the electric motor of the threaded spindle 33 which is thus rotated until the arm 26 is no longer in contact with either of the two switches 29. Accordingly, the control system in question is an automatic control system. As can be seen from Figure 2, the wire 5 may extend through the gradient beam, which is in the form of a tube, into the region of the rear support 8 of the gradient beam 4. In this case, the interval X shown in Figure 3, for which there are numerous possibilities of adjustment, and the point E may be fixed by inserting locking bolts 16 into the receiving bores 17 distributed over the length of the gradient beam 4. However, it is of course also possible to replace this step-by-step adjustment by means of locking bolts with a continuous adjustment drive, for example a hydraulic multistage cylinderand-piston assembly or a clamping mechanism which can be continuously shifted along the gradient beam. WHAT WE CLAIM IS:

1. A travelling machine for measuring and/or correcting the level of a railway track, comprising a levelling reference system, which consists of a gradient beam arranged on the machine in the rear, corrected section of track and extending in the longitudinal direction of the track, and of a levelling reference line extending over the uncorrected section of track and connected at its rear end to the gradient beam, and means for measuring the vertical distance between the levelling reference line and the track in the vicinity of the correcting tools, characterised in that the point at which the rear end of the levelling reference line is connected to the gradient beam is adjustable in the longitudinal direction of the track, to change the track level error reduction ratio, and in that the gradient beam is connected to an adjusting drive and to a means for monitoring the longitudinal direction of the gradient beam and controlling said direction so that it has a predetermined relation to the prescribed longitudinal gradient of the track.

secured to the lower part of the support and in that the connection between the lower part and the guide block or between the threaded spindle and the motor is in the form of joint, for example a universal joint or the like.

6. A machine as claimed in any of the preceding claims including means for controlling said direction of the beam automatically.

7. A machine as claimed in any of Claims I to 6, characterised in that the means for monitoring and controlling the longitudinal direction of the gradient beam is connected to a transmitter responsive to the position of a pendulum mounted substantially centrally on the gradient beam.

8. A machine as claimed in Claim 7, characterised in that the pendulum is pivotally mounted on the gradient beam to swing in the longitudinal direction of the beam about an axis transverse to the beam and comprises a pendulum rod fixedly connected to a feeler arm extending longitudinally of the track, and in that the feeler arm is provided with an extension extending into the vicinity of an electromagnet which is arranged on the gradient beam and which attracts transversely of the longitudinal axis of the beam.

9. A machine as claimed in Claim 8, characterised in that the transmitter is formed by two switches which are mounted at a vertical distance apart from one another, in particular on an intermediate support, and which can be adjusted together in their distance from the gradient beam through a vertical adjusting mechanism cooperating with an indicating scale.

10. A railway track maintenance machine substantially as herein described with reference to the accompanying drawing.