EP2122301A2

EP2122301A2 - Laser measuring method and system for checking longitudinal movements of the long welded rail both under construction and in operation

Info

Publication number: EP2122301A2
Application number: EP08751005A
Authority: EP
Inventors: Giorgio Pisani
Original assignee: Individual
Current assignee: Individual
Priority date: 2007-02-28
Filing date: 2008-02-25
Publication date: 2009-11-25
Also published as: WO2008129420A3; WO2008129420A2; ITMI20070385A1

Abstract

Measuring method and system by laser diastimeter of shiftings of the long welded rail in operation constrained to the track sleepers and under construction free from the track sleepers. The method allows only one person for carrying out all of the check operations provided by the LWR rules in operation and under construction with automatic filling of the suitable check forms.

Description

LASER MEASURING METHOD AND SYSTEM FOR CHECKING LONGITUDINAL MOVEMENTS OF THE LONG WELDED RAIL BOTH UNDER CONSTRUCTION AND IN OPERATION

Measuring method and system, using laser diastimeter, of dimensional parameters of the long welded rail in operation constrained by rail sleepers and under construction free from the rail sleepers. The method and system allow only one person to carry out all the checking operations provided by the LWR rules both in operation and under construction with automatic filling of suitable checking tables.

The checking operations in hand provide to carry out measures onto the long welded rail: • in operation constrained to rail sleepers, verifying that the rail in time undergoes only possible longitudinal movements consistent with the position realized during adjustment of inner strains of LWR

• under construction, free from rail sleepers, in order to determine the inner strains by the length of the rails at a certain temperature to verify proportionality of the elongations realized in the checking points of the manufacturing half-sections, with similar procedures and the possible addition of a temperature measuring device to the system. For a wider discussion of the conventional methodology of the LWR construction, reference may be made to the PCT/IT 2005/000698 patent application of the same applicant (WO 2007/063557). In order to understand the usefulness of such method and system it is preferable to consider how the above mentioned in operation checking operations have been carried out so far. For evaluating the inner strain condition of the LWR pairs of reference pegs were usually arranged at the rail sides, in order to materialize alignments perpendicular in respect of the rails and to measure shifting relative to engravings formed on outer rail heads of the rail. The alignments were materialized by stretching between the pegs harmonic steel or nylon cables. Normally the checking operation was carried out by at least four persons operating as follows: a pair of persons kept the cable stretched between the pegs; one person sighted trains; in case of bad visibility or in presence of particularly busy line more agents can be required; one person measured, on the rail, the shifting of the gravers in respect of the cable by a rod divided into millimeters.

A method equally expensive in terms of resources and time was used for installing the LWR. The subject system and method instead allow for carrying out the mapping of longitudinal shifting of the rail and for evaluating the inner strain condition of the LWR directly from the rail platforms, without involving or crossing the track; only one person can carry out the mapping.

The method provides the steps of: • placing laser diastimeter-holding supports on a fixed support such as supporting posts of the electric traction,

• placing one or more laser diastimeter on the laser diastimeter-holders,

• placing on the rail in a fixed manner a reflecting target set for laser diastimeter on both the rails, • carrying out a first sequence of reference measures by laser diastimeter consisting in the distance between the laser diastimeter and the reflecting target set,

• carrying out subsequent sequences of test measures by laser diastimeter consisting in the distance between the laser diastimeter and the reflecting target set, • processing data by a processor unit, possible storage and/or transmission and subsequent automatic filling of the forms regarding the in operation checks on the LWR,

• eventually, only in the laying step, measuring the rail temperature. The method uses the following system:

• laser diastimeter-holder supports to be placed on a fixed support such as supporting posts for the electric traction,

• one or more laser diastimeters to be placed on the laser diastimeter-holder supports, • a reflecting target set for laser diastimeter placed in a fixed manner on the rail,

• central computer provided with memory and possible wireless transmission by storage software for storing data and automatic filling of the forms regarding the in operation checks of the LWR,

• eventually, only in the installation step, rail temperature measuring device. The method consists in computing the longitudinal slip of the rail by indirect measures of the distance between a point defined by the laser diastimeter position and the laser reflecting targets integral with the rail. The laser diastimeter is connected in a simply removable manner to laser diastimeter-holder supports firmly anchored along the line close to the posts of the electric traction or other static construction and allowing for carrying out more measures with only one laser diastimeter. The method can use either fixed laser diastimeter-holders with double measure position in which the laser diastimeter is alternatively housed, or laser diastimeter-holder rotatable around two axes Y and X, vertical and horizontal, respectively, to allow the orientation by subsequent targeting of the laser diastimeter towards all the reflecting targets. Data are then processed, eventually stored and/or transmitted. A detailed description of the invention follows, with reference to a preferred embodiment thereof, given as illustrative and not limiting example, and shown in the annexed drawings, in which:

Fig. 1 shows a sectioned rail, fixed on a rail sleeper, with a fixed reflecting target mounted, according to the method subject of the invention;

Fig. 2 shows a schematic plan view of the arrangement of a first embodiment of the method subject of the invention;

Fig. 3 shows a schematic plan view of the arrangement of a second embodiment of the method subject of the invention; Fig. 3a shows a schematic plan view of the arrangement of a third embodiment of the method subject of the invention;

Fig. 4 shows a schematic side view of the arrangement of a first, second or third embodiment subject of the invention;

Fig. 5 shows a reference scheme computing for the slip dimensional parameters of a rail according to the method subject of the invention for the first and second embodiment;

Fig. 5a shows a reference scheme computing for the slip dimensional parameters of a rail according to the method subject of the invention for the third embodiment;

Fig. 6 shows a perspective view of a first embodiment of a not rotatable laser diastimeter support according to the invention; Fig. 7 shows a perspective view of a third embodiment of a not rotatable laser diastimeter support according to the invention; and

Fig. 8 shows a perspective view of a laser diastimeter support according to the invention with horizontal and vertical rotation axes, with a laser diastimeter mounted.

With reference now to the annexed drawings it is to be envisioned that the method uses the following system: • laser diastimeter 1 with laser beam in fig. 6, 7 and 8;

• laser diastimeter-holder fixed supports 2, in fig. 2, 3a, 6 and 7, or laser diastimeter-holder rotatable supports 4, in fig. 3 and 8, laser diastimeter- holder with two rotation vertical and horizontal axes; • fixed reflecting targets 3 in fig. 1, 2, 3, 3a and 4 of the laser beam, mounted on the rail;

• electronic device (not shown) capturing, processing and eventually transmitting data from the laser diastimeter, with software for storing and automatically filling the forms regarding the in operation checks of the LWR; • eventually, only in the installation step, a rail temperature measuring device.

Each support 2 and 4 and the targets 3 are realized in order to allow for repeating with high accuracy, during time, the distance measures from the same origin points and along the same directions set during the installation.

The laser diastimeter fixed supports 2 are made of machined slabs with high mechanical accuracy with the possibility to adjust tilt in respect of the vertical during installation. Each support allows the laser diastimeter into two positions to point and measure the distance of two different targets mounted on the same rail.

Each support is made to permanently rest in operation and allow the repositioning of the laser diastimeter, which is disassembled at the end of the measure, and orientation thereof according the primary installation. At each subsequent measure, the same measure point and the same reflecting targets, integral with the rail, are used for the laser diastimeter.

With reference to fig. 8 the support can be also revolving, with rotation onto two axes, X and Y, perpendicular each other in the output point of the laser beam from the laser diastimeter. The shafts allowing the horizontal and vertical laser rotation are provided with mechanical stops to be placed and locked during the installation of the support, when carrying out the first measure.

The accurate coupling of the laser diastimeter onto the different supports is assured by three bearing spherical points 7 which find always the same housing in the seats 6 of each slab 5.

In order to describe now details of the method, and with reference to the annexed drawings, the longitudinal slips of the rails are geometrically computed on the variations of the measures, carried out always from the same point, in respect of the targets integral with the rail. The possible longitudinal shifting S of the rails and the orientations thereof are computed applying the proportionality rule of similar triangles by the formula and following illustration hereinafter developed for clarity.

With reference to fig. 5, there are envisioned

S₁ and S₂, shifting of the targets integral with the rails a, c: reference measures carried out during the installation b, d: measures obtainable, once known the whole measure b+d carried out during installation ai, Ci: subsequent measures bi, d^ measures obtainable from geometric formulas S: average of the shifting that is S = (Si + S₂) / 2 that developed results

S = [(b₁ - b) + (d - d₁)] / 2 that is, according to the similarity law of triangles

S = [(a₁ - b) / a - b + d - (c₁- d) / c] / 2 The distance measure and the subsequent computing of the shifting are carried out by measuring on each rail the hypotenuses of two separate right-angled triangles, approached each other onto the cathetus which represents the height in respect of the bases parallel to the rail. Such measure can be carried out by only one laser diastimeter placed sequentially at two different horizontal angles. By changing the tilt of the diastimeter by rotation around the horizontal axis of the diastimeter-holder the shifting can be monitored of four point on two rails (fig. 3). The shifting of two rails can be measured also by repositioning of the same laser diastimeter on two different supports (fig. 2) with two different vertical angles.

The shifting computing for each rail is carried out as the average of two shiftings (one computed on the right-angled triangle on the right and the other on the right-angled triangle on the left), to minimize the effects of possible instrumental errors, potentially connected also to the possible different environmental conditions (brightness, temperature, etc.) of the different measure moments. This can be verified from the S = [(bi - b) + (d - d^] / 2 in which it is plausible that the measure errors of a single test have the same sign, and then they tend to cancel each other in such computing formula.

Alternatively to the above described similar triangle system, the longitudinal shifting S of the rail can be determined also as variation of the difference of two measures carried out from the diastimeter-holder along directions set perpendicularly in respect of the track, collimating towards two targets integral with the rail (fig. 3a). With reference to fig. 5a the first target will have reflecting surface parallel to the rail and the second reflecting surface sloping for 45 degrees (in case of sloping of the second target different from 45 degrees, the longitudinal shifting "S" will be determined by dividing the aforesaid difference by the trigonometric value of the incidence angle tangent of the surface sloping relative to the rail). For possible fixed stations, the laser diastimeter could be locked integrally on the revolving support and the targeting could be carried out by installing for each measure point four fixed laser diastimeters keeping the targeting direction on the targets mounted on the rails. All the systems are completed by electronic devices provided with GPRS or GSM modem interfacing a remote computer.

It is clear that to the particular embodiment, previously described as illustrative and not limiting, can be added several modifications, arrangements, integrations, variations and/or substitutions of elements, even regarding their displacement and material they are made of, without falling outside the scope of the invention, as determined by the following annexed claims.

Claims

1. Measuring method of longitudinal shifting parameters of long welded rail comprising steps of:

(i) positioning of supports (2; 4) for linear measuring instrument (1), (ii) positioning of one or more linear measuring instruments (1) onto said supports (2; 4) for linear measuring instrument, (iii) positioning firmly on each rail of at least a pair of targets (3) for linear measuring instrument (1),

(iv) carrying out of a first measures, by said linear measuring instrument (1), to obtain the measure of reference distance between said linear measuring instrument (1) and each target (3) of said at least one pair of targets (3), (v) carrying out of subsequent measures, in subsequent times, by said linear measuring instrument (1), to obtain the measure of the distance between said linear measuring instrument (1) and each target (3) of said at least one pair of targets (3), and

(vi) computing of said longitudinal shifting parameters by use of calculus models depending on said measures of the reference distance and said measures of distance.

2. Measuring method of longitudinal shifting parameters of long welded rail according to claim 1, wherein said calculus model is:

3. Measuring method of longitudinal shifting parameters of long welded rail according to claim 1, wherein said linear measuring instrument (1) is a laser diastimeter.

4. Measuring method of longitudinal shifting parameters of long welded rail according to claim 2, wherein said targets (3) are reflecting targets.

5. Measuring method of longitudinal shifting parameters of long welded rail according to one or more of the preceding claims, wherein an electronic computer, by a computer software implementing said calculus model, provides for:

(i) capturing measures carried out by said linear measuring instrument (1), (ii) computing said longitudinal shifting parameters, (iii) automatic filling of the forms regarding in operation checks of LWR, (iv) storing processed data, (v) transmitting processed data through computer network.

6. Measuring method according to one or more of the preceding claims, wherein a single linear measuring instrument (1) is alternatively installed on each of said supports (2; 4) so as to point to each of said targets (3).

7. Measuring method according to one or more of the preceding claims, wherein said linear measuring instrument (1) is installed on two of said fixed supports (2) each dedicated to a rail so as to point one by one to all the targets (3) on both the rails.

8. LWR Measuring method according to one or more of the preceding claims, wherein the method is used for in operation measures on LWR constrained by track sleepers.

9. LWR Measuring method according to one or more of the preceding claims, wherein the method is used during realization step of LWR free from track sleepers and there is further carried out rail temperature measure.

10. Measuring system of dimensional parameters of the long welded rail comprising:

(i) supports (2; 4) for linear measuring instrument (1),

(ii) one or more linear measuring instruments (1) to be placed on said support (2; 4) for linear measuring instrument (1), (Mi) at least a pair of targets (3) for linear measuring instrument (1) placed firmly on the rails, (iv) electronic computer operatively associated to said linear measuring instruments (1) and to a computer network.

11. Measuring system of dimensional parameters of the long welded rail according to preceding claim, in which said linear measuring instrument (1) is a laser diastimeter.

12. Measuring system according to claim 10, in which a accurate coupling between support (2; 4) and linear measuring instrument (1) is assured by three bearing spherical points (7) housed in corresponding seats (6) formed into a bearing slab (5).

13. Measuring system according to claims 10, 11 or 12, in which the fixed support (2) comprise slabs (5), having tilt adjustable in respect of the vertical line during installation step, machined at high mechanical accuracy, fixed on a permanently fixed support, and able to house said linear measure instrument (1) in positions suitable to pointing at least one target (3).

14. Measuring system according to claim 11 or 12, in which the supports for laser diastimeter fixed on a permanently fixed support, are rotatable supports (4), with rotating devices around two axes (X and Y) perpendicular each other at the output point of the laser beam from laser diastimeter (1), and shafts allowing horizontal and vertical rotation of laser are provided with mechanical stops to be placed and locked during installation of the support, before carrying out the first measure.

15. LWR measuring system according to one or more claims 10 to 14, in which said system is used for the in operation checks on LWR constrained to the track sleepers.

16. LWR measuring system according one or more claims 10 to 14, in which said system is used for measures during LWR realization step free from track sleepers and there is further used a device for measuring rail temperature.