EP0089702B1 - Method of guiding a track-positioning device, and apparatus for that purpose - Google Patents

Abstract

A guidance system permits of guiding the railroad track positioning device of a track renewal and maintenance machine as the machine moves in the track working direction. To this end the curvature of a track section to be worked upon comprised in a chord of predetermined length is measured and as a function of this curvature the direction of a second chord is measured, one end of this second chord being coincident with the rear end of the section whereas its predetermined and constant length is so selected that its other end lies on the already renewed or maintained track section and shows the position of a point of this section before the renewal or maintenance works.

Description

The object of the present invention is a method for guiding a rail track positioning device fitted to a machine for renewing or maintaining a rail track with respect to a reference base secured to the machine and a machine for the implementation of the process.

When renewing or carrying out maintenance work on a railway track, such as cleaning up the ballast, the new track or track after maintenance must be placed in the position it occupied before this work, or possibly moved. with respect to the old position to take account of a displacement in certain places of the track compared to the initial layout caused by a subsidence of the ground or a similar reason.

By lifting the track, for example for stripping during ballast remediation work, the rails are subjected to forces which cause geometric deformations of the track. In order for the track to be erected correctly, it is necessary to stuff, level and shift the track. These operations are carried out by one or more specially equipped site machines. However, the dressage work cannot always be carried out immediately after the ballast is rehabilitated because of differences in speed of construction machines and the imperatives of rail traffic, especially if it is a single track, it the track must be laid after the remediation of the ballast in a desired position either in the position before the remediation or in a position slightly offset from the old position.

The device to achieve this goal must be integrated into the renewal or maintenance machine respecting the template.

The methods usually used for dressing a railroad use a reference base composed of three distinct points two on the already prepared track and one on the track to be set up as described in patent FR-1 429 056. D ' after this last process, the deflection of the point located on the arc of the section of track erected with respect to the rope determined by the two points furthest from each other is measured and the value of the deflection d is determined 'a second point located on the section of track to be erected and the track is ripped at this second point until the value of the arrow measured at this point takes the desired and determined value.

The devices for implementing the method described in patent FR 1 429 056 use the geometry theorem known as the "power of a point with respect to a circle". Indeed the power of a point compared to a circle is equal to the product of segments delimited by this point and the points of intersection with the circle of any secant passing through this point. The point can be both inside and outside the circle. The point in question is materialized by a pivot through which pass two lines based respectively on the two reference points. The materialization of these straight lines is carried out in a first execution by two rods forming scissors, the pivot being inside the arc, the length of two rods being determined so that their four ends must rest on the 'arc of the track so that the arc is correctly drawn. One rod rests on the end of the arc not yet erected and on an intermediate point already erected while the second rests on the second end of the arc already erected the other end indicating the correct position of a fourth point of the arc which is brought to this position by shifting.

Another device, described in patent FR 1 429 056, similar to the previous one, uses two straight segments intersecting on the outside of the arc at a pivot point, one resting on the erect end of the arc and passing through a second point already erected while the second rests at the end of the un-erected arc and an intermediate point of this straight line indicates the position which must occupy the point to be erected.

The other variants proposed in patent FR 1 429 056 are similar to those already described, the materialization of straight lines being produced by cords, cables or rods and the arcs being either the axis of the track or the rails or an arc virtual at a fixed distance from the track.

The main drawback of the process described in patent FR 1 429 056 is that one of the points of the reference base is on the part of the track to be erected and therefore its position is imprecise, thus measuring the deflection of the third reference point and the positioning of the erected point are imprecise.

Another drawback of this method is that the reference base extends on either side of the point to be positioned, which complicates its implementation on a railway construction machine such as a stripper-screener.

The invention overcomes these difficulties and provides a method for copying the existing track before its renewal or maintenance which on one side is sufficient for a temporary dressing and on the other side allows to speed up the process of final dressage especially if the previous course of the track does not require a correction.

It is also possible to move part of the track from its old position if a movement in the other direction from the original layout was caused accidentally.

The method according to the invention is characterized by claim 1.

The advantages of this process are: the reference base depending exclusively on the old track, we have the assurance that the track will not be moved from its old position unless we want a displacement relative to this position to compensate for a displacement compared to the initial accidental alignment, this displacement being obtained by introducing a factor into the function giving the direction of the straight line passing through the rear end of the rope secured to the machine. For the same reason, the implementation of the method is facilitated because the reference base and the positioning device are located in different places and there is no problem to solve as regards their arrangement on the renewal machine or 'interview.

The positioning of the point after the renewal or the maintenance of the track can be done in two ways either one records the curvature of the section of the old track and after its renewal or its maintenance one positions a point of this section using the value recorded so that the point occupies its old position, or when measuring the curvature of a section of the old track, this value is used to position a point located on the part of the track that has undergone renewal or l 'maintenance if the section of the track comprising the point and the section of the old track has a constant curvature or if the said section has a variable curvature a value depends on the curvature measured and a factor taking into account the variation curvature. This is the second variant which we will describe below.

The invention also relates to a machine according to claim 5 for implementing the method.

• La figure 1 sert à illustrer le principe du procédé.
• La figure 2 est une vue de côté d'une dégarnisseuse-cribleuse équipée pour la mise en oeuvre du procédé de l'invention.
• La figure 3 est une vue en plan de la figure précédente représentant uniquement le dispositif de mise en oeuvre du procédé.
• La figure 4 représente un détail.

The accompanying drawing shows, by way of example, a device for implementing the method.

• Figure 1 is used to illustrate the principle of the process.
• Figure 2 is a side view of a screen stripper equipped for the implementation of the method of the invention.
• Figure 3 is a plan view of the previous figure showing only the device for implementing the method.
• Figure 4 shows a detail.

AFBC is an arc representing the middle of the track or an equivalent rail or arc at a constant and determined distance from the track. A and B are two points of this arc located or corresponding to the section of the old track. Point P is the point where the track is processed and which causes the geometric deformation of the track. The PC arc is shown exaggeratedly deformed and represents the actual position of the channel after the treatment (maintenance or renewal) while the PC arc in dotted lines is the desired position of the channel. The points of the arc extending after point C have already been positioned.

The distance AB = a is constant and determined, F is the midpoint of the arc AB but it could as well be another intermediate point. The distance between points B and C is equal to b which is a constant and determined value. According to the process by measuring the deflection of point F, we can calculate the angle β between the two virtual strings AB and AC so that point C is also on the same circle as points A and B. After having materialized the position calculated from point C the track is moved laterally to this point to bring it to the calculated position.

• Le rayon d'un arc de voie est habituellement de l'ordre de quelques centaines de mètres tandis que la longueur de cordes AB et BC est de l'ordre de 10 à 20 mètres et les flèches maximales pour ces valeurs sont de l'ordre de quelques centimètres. Ainsi on obtient les expressions simplifiées suivantes pour la flèche f et le calcul de l'angle (3
  
  où
  
  
  est la valeur de la longueur du segment GE de la médiatrice de la corde AB, E étant le point d'intersection de la corde BC avec la médiatrice. En réalité plutôt que de calculer l'angle il suffit de calculer la position du point E ainsi on détermine la position de la corde EBC. La position du point E est déterminée par la valeur de la longueur du segment GE = y = (2(a + b)/a) f (IV). La machine de mise en oeuvre du procédé décrit ci-dessous tient compte de cette dernière remarque. Si la courbure de l'arc ABC n'est pas constante il faut introduire un facteur tenant compte de la variation de la courbure, de même si l'on désire un déplacement de la voie par rapport à son ancienne position.

The angle β is determined by the following calculations, for which certain mathematical expressions have been simplified on the basis of the following considerations:

• The radius of a track arc is usually of the order of a few hundred meters while the length of AB and BC strings is of the order of 10 to 20 meters and the maximum arrows for these values are of the order a few centimeters. Thus we obtain the following simplified expressions for the arrow f and the calculation of the angle (3
  
  or
  
  
  is the value of the length of the segment GE of the perpendicular bisector of the cord AB, E being the point of intersection of the cord BC with the perpendicular bisector. In reality, rather than calculating the angle, it suffices to calculate the position of point E, thus determining the position of the EBC cord. The position of point E is determined by the value of the length of the segment GE = y = (2 (a + b) / a) f (IV). The machine implementing the method described below takes this last remark into account. If the curvature of the arc ABC is not constant, a factor must be introduced which takes account of the variation in the curvature, similarly if one wishes a displacement of the track compared to its old position.

We will describe a stripper-screener for the sanitation of the ballast equipped for the implementation of the method of the invention. It is obvious that any other maintenance or renewal machine can be equipped for implementing the process.

The screen stripper is made up of a tractor vehicle 1 running on track 2 to be cleaned and a second vehicle 3 running on the cleaned track. The towing vehicle 1 supports transporters 4, 5 for the evacuation of litter and a screener 6 for the purification of the ballast brought by the transporters 7, 8 and excavated by the stripping device 9. Other transporters 10 and 11 bring the cleaned ballast and distribute it behind the stripper 9 where it will be groomed by a tamping device 12, and behind the groomer to complete the missing ballast. In front of the stripper 9 a device not shown lifts the track to facilitate the stripping operation. Behind the purified ballast distribution conveyor 11 is a shifting device 14 for positioning the railway on the sanitized ballast.

The devices mentioned are known to those skilled in the art and they are capable of being modified without. depart from the scope of the present invention which relates solely to the method of guiding a device for positioning a railway track and a renewal machine or maintenance of a railway track equipped for the implementation of the process.

A rectangular frame 16 is suspended by four jacks 17 from the chassis 18 of the tractor vehicle 1. The frame is composed of four U-shaped sections, the perpendicularity being ensured by brackets 43 fixed to the four corners of the frame. Two track probes 19 and 20 are fixed to the two cross members 21, 22 of the frame 16 by ears 23, 24 respectively 25, 26. The position of these two feelers 19 and 20 is fixed relative to the frame 16 and they serve to materialize reference points A and B. More precisely, it is the midpoints A ′ and B ′ of their axes of rotation which are permanently located on the virtual arc 27 of the middle of the railway track 2 which constitute the reference base. A third track probe 28 is fixed to a spacer 29 of the frame 16 by two ears 30, 31. The midpoint F 'of its axis of rotation coincides with the midpoint of the arc A', B '. The probe 28 can move transversely relative to the frame 16 so as to always follow the track of the track. Finally, point C 'is the midpoint of the track at the point where the shifting device 14 operates. The distances between points A ', B' and B ', C' are constant and determined. The measurement of the deflection of point F 'in relation to chord A', B 'is the deviation of point F' in relation to line segment A ', B' when the track probes 19, 20, 28 are in contact with a line of rails of track 2. A spring 32 or 33 ensures contact of the probe 28 with a line of rails. A mechanical multiplier system automatically indicates the position of point E 'or its equivalent is composed of an arm 13 articulated to the probe 28, to the cross member 29 and to a bar 36 parallel to the cross member 29 by their respective midpoints F', 34 and 35. The ends of the bar 36 are articulated respectively at one of the ends of the two arms 37, 38 articulated in turn at two points 39 and 40 of two brackets 41, 42 ensuring the positioning of the cross member 29. The articulations 34 , 39 and 40 are fixed while the others are mobile. The position of the fixed joints 34, 39 and 40 relative to the arms 13, 37 and 38 is such that at a displacement f 'of the point F' corresponding a displacement y 'of the free ends 44 and 45 of the arms 37 and 38 in accordance with the relation (IV) above. The materialization of the EBC cord being carried out here by a light beam coming from a transmitter 46 occupying the place of point E or its equivalent is picked up by a receiver 47 occupying the place of point C or its equivalent it is advisable to place these two devices so that the light beam is not likely to be interrupted by an obstacle.

The transmitter 46 and the receiver 47 are then placed at a location offset laterally and vertically from the arc A ', B', C ', that is to say that an arc A ", B" is considered, C "equivalent to the arc A ', B', C 'obtained in principle by a homothety and a translation. The point A" is not materialized because it is not of interest, the point B "is materialized by a small vertical slit on a screen 52 intercepting the light beam emitted by the emitter 46 being at point E ", and thus letting through a thin beam of light 48 materializing the cord B", C ". The transmitter 46 occupies at all times, as far as the feelers 19, 20 and 28 are in contact with the file of rails, the position E "which is at a distance Y" from the cord A ", B". The transmitter 46 is supported by a vertical rod 49 (fig. 4) articulated to a horizontal arm 50 pivotally mounted on an axis 51 at the end 45 of the arm 38. The axis 51 is guided at its upper end by a slide 53 sliding on a slide 54 fixed on the cross-member 29. The articulations of the rod 49 and of the arm 50 allow the transmitter to be brought back inside the template determined by the frame 16. The perforated screen 52 is fixed with a analogously on the frame 16 in the extension of the axis of the probe 28. The receiver 47 is composed of several photosensitive elements and it is divided into three vertical zones. If the light beam 48 passing through the screen 52 is picked up by the elements of the middle zone, the point of the path corresponding to point C "is at the desired position, if on the other hand it is picked up by the elements of one of the others zones the track must be moved so that the beam is captured by the elements of the middle zone. The receiver 47 is fixed on the shifting device 14. When the light beam is captured by the elements of one of the external zones of the sensor 47 a signal is sent to a device indicating the direction and the displacement which the track must undergo to occupy the desired position.

It is clear that for the transition curves one must take into account the variation of the curvature by introducing correction factors.

The device described also serves to control the alignment of the track on the straight line sections, the points E ", B" and C "having to be aligned parallel to the track. The transmitter 46, the receiver 47 and the screen 52 can be installed on one side or the other of the machine. It can be installed on two sides (E "', B"', C "') because they also make it possible to check that the gauge is not exceeded or is not obstructed by a foreign body, in fact if an obstacle interrupts the light beam between the transmitter and the receiver a buzzer sounds and the running of the machine is interrupted.

The mechanical multiplier device described can be replaced by a pneumatic or electric hydraulic device.

By acting for example on the length Y, the track can be moved relative to its old position.

• A'B'=11,5 m
• _A'F' = ₅,₂₅ m
• B'C'=19 m

For walking up and down the frame 16 is retracted under the chassis 18 of the tractor vehicle 1. By way of example we give the distances between points A ', B', C 'of an embodiment envisaged by the depositor .

• A'B '= 11.5 m
• _{A'F '= 5, 25} m
• B'C '= 19 m

It is possible to integrate a microprocessor which records the layout of the old track and calculates the position of the transmitter so as to reproduce the same trace after renewal or maintenance or to move it relative to the old position.

Claims (8)

1. Method of guiding a railroad track positioning device on a track renewal or maintenance machine with respect to a reference base rigid with the machine, characterized by the steps of measuring the curvature of a section (AFB) pertaining to the old track alone, before the renewal or maintenance work proper, said section being sustended by a chord (A, B) rigid with the machine and of a predetermined constant length (a), passing through the point (B) constituting the rear end of said chord (A, B) in the direction of travel of the machine, a straight line, the direction of which with respect of said chord being a function of said measured curvature, and taking on said straight line a constant length (b) measured from said point (B) and defining at its other end (C) the desired position of the track to be positioned.

2. The method of claim 1, characterized in that the direction of said straight line is a function only of the measured curvature.

3. The method of claim 1, characterized in that the direction of said straight line is a function of the measured curvature and of a factor taking due account of the variation of said curvature or/and of an intentional shift in relation to the old track.

4. The method of claim 1, characterized in that the value of the measured curvature is recorded and said desired position is determined utilizing said recorded value.

5. A railroad track renewal or maintenance machine for carrying out the method of claim 1, which is equipped with a device for positioning the track, a reference base (A, B) and means for guiding said positioning device (E, B, C), characterized in that said device for measuring the curvature of said section is rigid with one portion of said machine travelling on the old track, and that the positioning device is mounted on a portion of the machine which travels on the renewed or maintained track.

6. The maintenance machine, notably for cleaning the ballast, as claimed in claim 5, which comprises notably a tractor vehicle (1) rolling on the old track and another vehicle (3) rolling on the renewed or maintained track, both vehicles (1, 2) supporting track lifting means, ballast clearing means (9), ballast screening means (6), means for conveying the ballast to be cleaned (7, 8), the cleaned ballast (10, 11) as well as the rubbish (4, 5), and track shifting means (14) for positioning the cleaned track, characterized in that a rectangular frame (16) is suspended through extensible means (17) underneath the chassis (18) of the tractor vehicle (1) and so as to extend parallel to the track plane, said frame (16) being provided on the one hand with a pair of fixed track feelers (19, 20) disposed at a predetermined and fixed relative spacing, the centers (A', B') of said feelers corresponding to the ends of the chord rigid with the machine, and on the other hand with a third track feeler (28) disposed between said fixed track feelers (19, 20) and movable in a transverse direction for measuring the height of the arc from the chord at a point (F') of said track section or the equivalent thereof which is limited by said pair of fixed track feelers (19, 20), that mechanical, pneumatic, hydraulic or electrical means are provided for recording the value of said height at said point (F'), and for calculating and displaying the position of a point that defines with the rear end (B') of the chord rigid with the machine or of the equivalent (B", B"') thereof, the direction of said segment of the straight line (B'C') or of its equivalent (B"C" ; B"'C"'), and that receiver and comparator means (47) rigid with the point (C') to be positionned or with the equivalent (C", C"') thereof are provided for receiving a signal emitted by an emitter (46) disposed at the point displayed by said mechanical, pneumatic, hydraulic or electrical device, or at the equivalent (E", E"') thereof, said signal showing the position that said track point or the equivalent (C", C"') thereof must occupy, the difference between the position thus shown and the position actually occupied by said point being transmitted to means controlling said shifting device (14).

7. The machine of claim 6, characterized in that said emitter (46) is a source of unidirectional light beam.

8. The machine of claim 6, characterized in that said comparator (47) is composed of a photoelectric pick-up divided into three vertical areas, the reception of said signal by the central area of the pick-up showing that said point (C') or its equivalent (C", C"') actually lies in the shown position.

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