GB2292461A - Inclination gauge - Google Patents

Abstract

An inclination gauge suitable, among other purposes, for determining the degree of transverse cant on railway lines comprises a rigid elongate bar 11, electronic means for monitoring the extent of deviation of the bar relative to the horizontal, and display means 24 for displaying a result of the monitoring. As shown the inclination of the bar is measured by means of a pendulum 15 carrying a drive coil which interacts with two pick-up coils 20, 21. Alternatively the pendulum may carry a magnet which acts on Two Hall-effect devices (40, 41 Fig. 4). <IMAGE>

Description

Inclination Gauge The present invention is an inclination gauge.

It has been devised to enable the determination of degree of transverse cant on railway lines but has several other possible applications.

The two parallel rails of a railway track are set at the same height where the track is essentially straight but on a curved length of track the outer rail is set higher than the inner rail in order to counteract the centrifugal forces upon a train. The required track camber is conventionally defined as a difference in height between the rails, determined by measurement transverse to the track.

The device which is currently widely used for determining this height difference or cant, and which has been in use for many years, takes the form of a rod, of suitable length to span the gap between the two rails and supporting a spirit level in the region of its centre. A height adjuster at one end of the rod enables the height of that end to be varied relative to the adjacent rail until the rod is shown by the spirit level to be horizontal and then the height difference is read off a scale associated with the adjuster.

This crude device suffers from numerous disadvantages. Measurements may be unreliable because the reading of the level can be subjective.

The size of the bubble in the spirit level varies with the ambient temperature. If the device is used in adverse conditions, for example in the dark or in bad weather, accurate determinations are either very difficult or impossible.

It is an object of the present invention to provide an improved inclination gauge, by means of which some at least of the disadvantages of the presently-used cant gauge are reduced or avoided.

The inclination gauge according to the present invention comprises a rigid elongate bar, electronic means, secured upon the bar, for monitoring the extent of deviation of the bar relative to the horizontal and display means for displaying the extent of said deviation or a value or indication derived therefrom.

Thus the inclination gauge may display a value which is the angular inclination of the bar, or the difference in height between the ends of the bar, or a figure representing the extent by which the inclination, expressed as an angle or a linear amount, differs from a pre-determined desired value.

As an alternative, it may simply display an indication that the value does or does not differ from, or is greater or less than, that desired value.

The display may be illuminated, or adapted to be illuminated, to enable it to be read in poor conditions or after dark.

The display means may also be mounted upon the bar but, as an alternative, it may be separate from the bar, for example as a hand-held unit, and linked to the deviation monitoring means by a cable link or even by radio.

The electronic means for monitoring the deviation of the bar from the horizontal may be based upon detecting the position of a gaseous bubble or upon an electrostatic method of monitoring inclination but it is particularly preferred that it should be an electronic device which monitors the orientation of a pendulum. Thus, in one embodiment of the inclination gauge according to the invention, a driver coil is supported upon a pendulum and the position of the driver coil as the pendulum swings is monitored by a pair of pick-up coils in which a current is induced by the driver coil. In a second, preferred embodiment, the pendulum supports a magnet and the position of the magnet as the pendulum swings is monitored by a pair of Hall-effect transducers.

When the monitoring means incorporates a pendulum as aforesaid, it is highly desirable that the pendulum be at least partly immersed in a damping fluid, for example a suitable oil. Preferably the pendulum is suspended from a support bracket, adjustment of which allows the position of the pendulum relative to the bar to be set, and the display zeroed or calibrated, before the gauge is used.

When the gauge is intended for use upon railway tracks, the value of cant is usually required to be determined between the crowns of the two rails. To assist the placing of the gauge relative to the crowns, a guide is preferably provided, for example a stop for locating against one of the rails, the stop being spaced from the adjacent point of measurement of the gauge by the appropriate distance to locate the point upon the crown of the rail. The locating of the second measurement point upon the crown of the second rail is set by the length of the bar between the two points. The actual contact of the gauge with the rails may not in fact be point contact. In one form of the invention, the gauge may be supported at one end upon a pair of points and at the other upon a single point.However, in a preferred embodiment of the invention for use upon railway tracks, a flat plate is provided at one end for contact with the first rail and a half-round skid rests upon the highest point of the other rail.

The electronic deviation monitoring means in the inclination gauge according to the present invention, and optionally the display means, is preferably contained within a sealed housing, which preferably is sufficiently robust to be usable in adverse outdoor conditions. Advantageously the housing may be located adjacent to one end of the bar, most preferably an end provided with a locating guide as mentioned above. One or more batteries will usually be provided, normally within the housing, to provide the electrical power to drive the inclination monitor and the display means.

As stated above, the main purpose for which the gauge of the present invention has been devised is for determining transverse cant on rail tracks. The gauge may be used in the maintenance or up-grading of existing tracks or in laying new track. For this purpose, the bar should be of such a length as to locate the points of measurement to be compared upon the crowns of the two rails. However the gauge may also be used for measuring the camber on roadways or other surfaces, for example following a road traffic accident. For this purpose, the bar may be shorter, for example set to determine the relative height of two positions as little as about one metre apart.

In another possible form of the gauge, the bar may be of variable length, for example telescopic, or one of the measurement points may be slidably set along the bar. For these various other purposes, the gauge may provide three-point contact with the surface or surfaces being measured, as described above.

In yet another possible form of the gauge according to the present invention, the "twist" in a railway track, that is the rate of change of transverse cant over a given length of track, is determined. For this purpose, the gauge may be designed to be rolled along the track and data relating to the values of cant, measured continuously or at short intervals, may be processed by a computer incorporated in the gauge to determine the twist.

The invention will now be further described, by way of example only, with reference to the accompanying drawings, wherein: Fig.l is a schematic representation of a first embodiment of the gauge, for monitoring cant on a railway track; Fig.2 is an elevation showing a second embodiment of the gauge, also for a railway track; Fig.3 is an elevation, partly in section, perpendicular to that of Fig.2; and Fig.4 is a detailed view of the electronic inclination monitoring device of Figs. 2 and 3.

The cant gauge illustrated in Fig.l comprises a robust sealed housing 10, mounted rigidly upon one end of a rigid bar 11 of circular cross-section. A guide 12 extends downwardly from the bar 11 and is so spaced from a pair of support points 13 (only one of which is visible in the drawing) on the underside of the housing 10 that, when the guide 12 abuts the inside face of a first rail, the points 13 rest upon the highest point in the rail cross-section. At the other end of the bar 11, a single further support point 14 lies at a distance from the points 13 equal to the standard rail gauge (1.435 m) and therefore rests upon the highest point of the second rail of the track.

Within the housing 10, a pendulum 15 is pivoted at 16 upon a support bracket 17. The upper end of the pendulum carries a driver coil 18, supplied by an oscillator 19. As the pendulum 15 swings about the pivot 16, the position of the driver coil varies relative to two pickup coils 20, 21 and the induced voltage in the pickup coils is an indication of the extent of displacement of the driver coil 18 from the central position corresponding to a horizontal orientation of the bar 11. The induced voltage will be positive or negative respectively depending upon whether the support point 14 is lower or higher than the support points 13.

By means of a phase-sensitive demodulator 22 and scaling circuit 23, the output from the pickup coils can be presented as a display on a digital voltmeter 24 in the form of a difference in height in millimetres between the crowns of the two rails.

The display may be illuminated if ambient conditions require it.

The pendulum support bracket 17 is attached to the housing 10 by jack screws (not shown), which allow the position of the bracket to be adjusted so that the instrument gives a zero reading when the support points 13, 14 are on a level plane. After zeroing in this way, the gauge may be placed with the support points at a predetermined height difference and the scaling electronics can then be adjusted to give an accurate reading on the display. The gauge is now ready for use in measuring the cant of a pair of rails.

The second embodiment of the inclination gauge according to the invention, illustrated in Figs. 2 to 4, comprises a housing 30, rigidly mounted upon a locating bracket 31 at the end of a rigid bar 32 of circular cross-section. The bracket 31 forms a flat under-surface which rests upon the crown of a first rail 33 when one limb of the bracket abuts the inwardly-directed face of the rail. The length of the bar 32 is such that, when the bracket 31 is located on the rail 33 as aforesaid, a skid 34 at the other end of the bar rests upon the crown of the parallel second rail 35.

Within the housing 30, a sealed pendulum unit 36 is adjustably mounted by means of jack screws (not shown). The unit 36 contains a pendulum 37, suspended upon a low-friction pivot 38 with its lower end largely immersed in a damping fluid 39. The pendulum assembly incorporates a magnet, the position of which within the housing at any given time is detected by two analogue Hall-effect devices 40, 41.

When the unit is level, a null voltage appears at the display 42. When the end of the bar at the second rail 35 is higher than that at the rail 33, the displayed result corresponds to a positive output voltage from the device, while a negative output voltage is produced when the rail 35 is lower than rail 34.

Provision is made for adjusting the orientation of the pendulum unit 36 within the housing 30, and for calibrating the display, in the same manner as for the device shown in Fig.l. When the device is thus prepared for use, cant measurements are made by depressing a push-button 42 and reading the resulting display at 43.

In one form of the device, the display unit 43 displays a value which is the difference in height between the two rails. In another form, a desired value of the cant is pre-set into the device and the display simply shows whether the end of the bar 32 remote from the housing 30 needs to be raised or lowered, by addition or removal of ballast under the rail, to achieve the desired degree of cant.

Claims (16)

1. An inclination gauge comprising a rigid elongate bar, electronic means, secured upon the bar, for monitoring the extent of deviation of the bar relative to the horizontal and display means for displaying the extent of said deviation or a value or indication derived therefrom.

2. An inclination gauge as claimed in Claim 1, wherein said display means displays the difference in height between the ends of the bar.

3. An inclination gauge as claimed in Claim 1, wherein said display means displays a figure representing the extent by which said deviation differs from a predetermined value, or an indication that the deviation does or does not differ from, or is greater or less than, a predetermined value.

4. An inclination gauge as claimed in any of the preceding claims, wherein the display is illuminated or adapted to be illuminated.

5. An inclination gauge as claimed in any of the preceding claims, wherein the display means is also mounted upon the bar.

6. An inclination gauge as claimed in any of Claims 1 to 4, wherein the display means is separate from the bar and linked to the deviation monitoring means by a cable link.

7. An inclination gauge as claimed in any of the preceding claims, wherein the electronic means for monitoring the deviation of the bar from the horizontal is an electronic device which monitors the orientation of a pendulum.

8. An inclination gauge as claimed in Claim 7, wherein the pendulum supports a driver coil and the position of the driver coil is monitored by a pair of pick-up coils in which a current is induced by the driver coil.

9. An inclination gauge as claimed in Claim 7, wherein the pendulum supports a magnet and the position of the magnet is monitored by a pair of Hall-effect transducers.

10. An inclination gauge as claimed in any of Claims 7 to 9, wherein the pendulum is at least partly immersed in a damping fluid.

11. An inclination gauge as claimed in any of Claims 7 to 10, wherein the pendulum is suspended from a support bracket, the position of which is adjustable relative to the bar.

12. An inclination gauge as claimed in any of the preceding claims, having a guide to assist the locating of the gauge relative to the position to be monitored.

13. An inclination gauge as claimed in any of Claims 1 to 12, which is adapted to be rolled along a railway track and to monitor said deviation continuously or at short intervals.

14. An inclination gauge as claimed in any of Claims 1 to 11, wherein the bar is of variable length.

15. An inclination gauge substantially as hereinbefore described with reference to, and as illustrated in, Fig.l of the accompanying drawings.

16. An inclination gauge substantially as hereinbefore described with reference to, and as illustrated in, Figs. 2 to 4 of the accompanying drawings.