EP0735190B1 - Process for screwing and unscrewing the sleeper screws of a railway track and apparatus for performing the process - Google Patents

Abstract

On the trolley front, optical detectors, e.g. CCD cameras, 97), and processors (8) produce images giving the distance (XO+XD) of the spikes (5)on successive sleepers (4) from the origin of an orthogonal reference frame (X, Y, Z). A Roller-driven sensor (9) gives the trolley displacement (XO). The module (10) carrying the driving tools (16) rests on rollers (12), and is positioned on a rail (11) in the trolley by a horizontal actuator (13). Further actuators (17, 20) position the tools vertically and transversely. Tool coordinates pass to a central controller (6), also receiving optical (8) and rolling (9) sensor signals, via position sensors (15, 19, etc.). Tools can be skewed slightly at inaccurately driven spikes. The controller (6) implements all positioning and operating tasks, clamping the module (24) to the rails (3) during the latter, the trolley continuing meantime.

Description

The present invention relates to a method of screwing and unscrewing the lag bolts of a railroad track according to which a carriage advancing on the track and carrying lag bolt detection devices and threading heads is used, as well as a machine for setting of the process.

When laying or removing the rails of a railway track, light individual screw drivers are most often used, each actuated by an operator. It therefore takes four people to screw or unscrew the four bolts of a sleeper at a relatively rapid rate of 200 to 250 meters per hour.

It is the only manual means currently known which can accurately position a dowel head on the head of a dowel. Often, this is not in its theoretical place, either because the cross is not parallel to the others, or because the cross is in a curve, or because the cross has been misaligned or for any other right. The lag screw can also be inserted obliquely instead of being located on a plane perpendicular to that of the axis of the crosspiece.

FR-A-2 682 135 and FR-A-2 666 358 have proposed machines operated by a single operator. The machines described in these documents have two double drawing heads to act simultaneously on the four bolts of a cross member, a double head acting by rail file.

In document FR-A-2 682 135, the four heads are lowered simultaneously, after their positioning relative to the four lag bolts, the detection of the nuts being carried out by mechanical feelers. Document FR-A-2 666 358 provides for the individual descent of each of the heads and also the possibility that a beam supporting the double heads can pivot relative to an axis perpendicular to the plane of the track to be placed parallel to an oblique cross. There is no provision for prior detection of the nuts other than that made visually by the operator.

The installation of the dowel heads and the initiation of operations are carried out by an operator behind the two double dowel heads.

These devices allow, of course, to improve working conditions because instead of four people, one person is employed to control the machine. Nevertheless, the positioning of the drawing heads relative to the lag screws is done either by rudimentary mechanical feelers, or visually by the operator. It follows that the precision of positioning of the tools relative to the lag screws and the speed of execution depend above all on the skill and experience of the operator. As for the adjustment possibilities, if only for the inclined lag bolts, they are limited or even absent.

Document FR-A 2 072 853 presents a machine for carrying out railway work. In particular, a process for screwing and unscrewing lag screws of a railroad is implemented by this machine which comprises a vehicle advancing on the track and supporting threading heads and bolt detection devices.

The object of the present invention is to propose a method and a machine making it possible to remedy the drawbacks of the prior art and to ensure high quality work at a high rate.

The method according to the invention is defined by the characterizing clause of claim 1.

• le fait que l'on détermine la position relative exacte des tirefonds par rapport aux moyens de vissage de préférence avec un capteur sans contact permet par la suite de positionner individuellement chaque tête de tirefonnage par rapport au tirefond avec exactitude,
• le fait que l'on peut incliner chaque tête individuellement par rapport au plan de la voie permet de l'adapter à une éventuelle position oblique d'un tirefond,
• le fait que chaque tête est déplaçable et enclenchable individuellement permet de traiter chaque tirefond individuellement, ce qui divise par quatre, voire par huit, le taux de "ratés" et évite que les traverses de béton se fissurent,
• le fait que toutes ces opérations sont réalisées de manière purement automatique sans aucune intervention humaine, par des moyens techniques fiables ne nécessitant pas d'investissement financier déraisonnable, permet des économies de frais de personnel, lequel est libéré de tâches répétitives ingrates, et assure une précision optimale du couple de serrage des tirefonds.

The advantages of the process according to the invention are:

• the fact that the exact relative position of the lag bolts is determined relative to the screwing means, preferably with a contactless sensor, makes it possible thereafter to position each bolt head relative to the lag bolt individually,
• the fact that each head can be tilted individually relative to the plane of the track makes it possible to adapt it to a possible oblique position of a lag screw,
• the fact that each head is movable and snap-on individually makes it possible to treat each lag screw individually, which divides by four, or even by eight, the rate of "misfires" and prevents the concrete sleepers from cracking,
• the fact that all these operations are carried out in a purely automatic manner without any human intervention, by reliable technical means not requiring no unreasonable financial investment, allows savings in personnel costs, which is freed from unrewarding repetitive tasks, and ensures optimum precision of the tightening torque of the lag bolts.

Thus, not only are the labor costs eliminated, but the tools positioning operations relative to the lag screws are done precisely and quickly, without depending on the skill and speed of execution of a no one.

• a1. une base de référence orthogonale XYZ est définie, X étant parallèle à l'axe du rail, Y parallèle à la traverse et Z perpendiculaire au plan XY,
• a2. la position du chariot sur la voie est mesurée en permanence par rapport à la base de référence,
• a3. la position relative de chacune des têtes de tirefonnage est mesurée en permanence par rapport au chariot,
• a4. la position de chaque tirefond est détectée et calculée par rapport à la base de référence et,
• a5. l'écart de chaque tirefond par rapport à la tête de tirefonnage est calculé.

According to the method, the relative position of a lag screw relative to the corresponding screw head is determined according to the following steps:

• a1. an orthogonal reference base XYZ is defined, X being parallel to the axis of the rail, Y parallel to the cross-member and Z perpendicular to the plane XY,
• a2. the position of the carriage on the track is continuously measured relative to the reference base,
• a3. the relative position of each of the dowel heads is continuously measured with respect to the carriage,
• a4. the position of each lag screw is detected and calculated relative to the reference base and,
• at 5. the distance of each lag screw from the thread head is calculated.

Preferably, the different measured positions are recorded progressively to allow an improvement in the working rate of the carriage. So, it is not necessary to wait for the end of a work cycle to measure the positions of the lag screws which will be treated later.

• a. blocage longitudinal de la tête sur le rail correspondant,
• b. descente rapide vers le tirefond,
• c. introduction de l'outil saisissant la tête du tirefond,
• d. mise en rotation de l'outil,
• e. mesure du couple de serrage,
• f. arrêt automatique lorsqu'une valeur prédéterminée de couple de serrage est dépassée,
• g. dégagement de l'outil et remontée rapide, et
• h. déblocage de la tête du rail correspondant.

According to a particular embodiment of the method, the threading cycle for screwing comprises the following steps after positioning of a threading head relative to the lag screw:

• at. longitudinal locking of the head on the corresponding rail,
• b. rapid descent to the lag screw,
• vs. introduction of the tool gripping the head of the lag screw,
• d. tool rotation,
• e. measurement of the tightening torque,
• f. automatic stop when a predetermined tightening torque value is exceeded,
• g. quick release of the tool, and
• h. release of the head of the corresponding rail.

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

The machine comprises a carriage provided with means for moving on the track, means for detecting and determining the relative position of a lag screw with respect to a drawing head, of a module per line of rails equipped with at least one dowel head, said module being arranged to be able to be moved relative to the carriage in the direction of the axis of the rail queue, said dowel head being provided with means to be moved relative to the module in a first direction parallel to the axis of the rail line, in a second direction perpendicular to this axis and parallel to the cross-member, in a third direction perpendicular to the plane defined by the two previous directions, and angularly with respect to this third direction, and automatic means individually initiating a drawing cycle for each head.

With the method according to the invention and the implementation machine, the depositor obtained a rate of 400 meters per hour.

The invention will be described in more detail using the attached drawing.

Figure 1 is a schematic side view of the carriage.

Figure 2 is a partial cross-sectional view of a rail on a cross member.

Figure 3 is a plan view of a rail on sleepers.

FIG. 4 is a side view of a carriage more detailed than FIG. 1.

Figure 5 is a cross-sectional view showing a double dowel head in the working position.

Figure 6 is a block diagram of a device for controlling the positioning of each dowel head.

The carriage 1 shown in Figure 1 is provided with a drawbar 2 by which it is connected to a machine ensuring locomotion of the carriage. The carriage moves on the rail 3 fixed to the crosspieces 4 by means of lag screws 5, 26. The carriage 1 could be provided with autonomous displacement means.

The carriage 1 is provided with a group 6 ensuring the supply of energy, both hydraulic and electric. An optoelectronic device 7 for detecting and measuring the position of the lag bolts is arranged on the front part of the carriage. In principle, such a device per line of rails is used. The device 7 is connected to a box 8 for storing and processing all the electronic data. An encoder 9 disposed at the rear end of the carriage gives the position X ₀ of the carriage at all times on the rail 3. The carriage 1 is provided on its upper part with a horizontal rod 11 secured to the carriage 1 on which a module slides 10 provided on its lower part with two rollers 12 ensuring its guiding with respect to the rail 3. The module 10 is moved along an axis X parallel to the axis of the rail by a jack 13 controlled by a servovalve 14. The position X _M of the module 10 with respect to the carriage 1 is indicated by a linear potentiometer 15. The module 10 carries two drawing heads 16, 16a of which only one is visible in FIG. 1. Each head is provided with a jack 17 actuated by a valve 18 for raising and lowering the dowel head. A linear encoder 19 makes it possible to know the height of the head at any time. A double-acting cylinder 20 supplied by a valve 21 ensures the transverse displacement of the head 16 by sliding it on transverse guides 22. An encoder 23 makes it possible to measure the transverse displacement of the head (Fig. 3).

To allow the immobilization of module 10 in relation at rail 3, the module is provided at its lower part with two clamps 24 actuated by jacks 25 (Fig. 4). Thus, when the drawing head 16 is located above a lag screw 26 detected and located beforehand by the device 7, the clamps make it possible to immobilize the module relative to the rail 3 so that the head 16 can unscrew the lag screw.

The device 7 is an optoelectronic device, for example a CCD camera (for Charge Coupling Device) with high resolution. Such a camera is, in principle, used for each row of rails. Indeed, the image captured by this camera is divided into two parts, namely one part by lag screw. The position of each lag screw is thus captured in an XY plane (see definition below), which makes it possible to guide each bolt head individually.

The execution shown in Figure 4 is more detailed. The carriage 1 is also equipped with a module 10 provided with two drawing heads 16 and 16a. The head 16a is shown in the high position and it is identical to the head 16. It is mounted on two guide columns 27 secured to a sheath 28 sliding on a guide rod 29. A jack 30 controlled by a valve not shown acts on a reference 31 formed by a triangular plate one of the vertices of which is secured to the end of the jack 30, another vertex is secured to a rod 27a secured to one of the guide columns 27 and the third provided with a encoder 32 is articulated around an axis 31a integral with the module 10.

The heads 16 and 16a are independent of each other concerning the direction of movement along three orthogonal axes X, Y, Z inside of course the module 10.

In order to allow the inclination of the head 16 by an angle ϕ to tighten or loosen oblique lag bolts relative to the crosspieces, a jack 33 (FIG. 5) allows by its extension the inclination of the head by pivoting around the rod guide 29. In Figure 5 there is shown the drawing head 16 in a position perpendicular to the cross member 4, that is to say corresponding to an angle ϕ equal to 0 °. This angle could vary up to approximately 5 ° by the sole extension of the jack 33.

The potentiometer 15 in FIG. 1 enabling the displacement of the module 10 to be known has been replaced in FIG. 4 by a rotary encoder 34 driven by a belt 35, the two ends of which are fixed on two anterior and posterior faces of the module 10, in particular at points 10a and 10b. Three return rollers 34a, 34b, 34c ensure the movement of this toothed belt during the movement of the module 10 inside the carriage.

In FIG. 4, the module 10 is suspended from a tube 11 by two pairs of rollers 36, 37, 38, 39 which ensure the suspension and the guiding of the module 10, its displacement being provided by the jack 13. Each drawing head 16 comprises a hydraulic motor 16b with incorporated reduction gear, a counter 16c for the number of revolutions and a key 16d.

From this machine, the method according to the invention will now be described.

When the carriage 1 advances on the rail 3, the detector 7 captures and stores the exact position of each lag screw in the XY plane of an orthogonal reference base XYZ defined as follows: X is an axis parallel to the axis of the rail 3 and located on the top of the rail, Y is an axis perpendicular to the previous one and parallel to the cross-member, located on the internal side of the rail, Z being perpendicular to the plane defined by the two other axes.

Thus, for a cross member i, the bolt coordinates are the pairs X _1i Y _1i , X _2i Y _2i , X _3i Y _3i , X _4i Y _4i . The computer then calculates the differences ΔX, ΔY between the positions of the lag bolts and those of the corresponding heads along the two axes X and Y.

The slave jacks 13, 20 and 30 bring each of the heads above the lag screws to be treated, for example the lag screw 26. In other words, the heads move until the differences ΔX, ΔY are zero. The jack 25 then closes the clamp 24 to immobilize the module 10 and the cycle of each drawing head begins, namely: the descent to the lag screw, the screwing and the ascent. Subsequently the module 10 is released by loosening the clamp 24 and it moves in the direction of the lag bolts of the next crosspiece.

Referring now to FIG. 1, the calculation of the differences ΔX, ΔY could be represented in more detail. Indeed, the position of the carriage 1 and in particular that of its rear part (in the direction of movement during work) is X ₀ ; the distance between this rear part of the carriage and the position of the detector being X _D , the absolute position of the lag bolts of a crosspiece detected by the detector 7 will be X _i = X _0i + X _D , X _0i being the reference position carriage for cross member i. In the same way for the lag screw which is at position i + 1, we will have X _{i + 1} = X ₀ (i + 1) + X _D etc. The position of the module on the carriage being X _M , thus the distance to be traveled by a dowel head to arrive at the position X _i is equal to ΔX _i = X _i - (X _M + X _0M ), X _0M being the position of the carriage at the time of calculation. A hydraulic system receiving the design values allows the heads to be moved through hydraulic valves supplying the control pistons (see fig. 6).

The displacements along Y and Z are simpler since it suffices to know the positions Y _i and Z _i of the lag bolts and Y _M and Z _M of the module and to cancel the difference Y _i -Y _M and Z _i -Z _M when ΔX _i = 0.

The value of the angle ϕ is preset on the basis of visual observations prior to the work or in accordance with the data established during the installation of the track. However, if for one reason or another, one of the lag bolts has been pressed with an angle which differs from the preset angle ϕ, when the tool 16d tries to grasp the head of the lag bolt, an auto-adjustment of the angle ϕ is produced around the preset position so that the tool 16d can grasp the lag screw without destroying it.

In the block diagram of FIG. 6, we have shown a lag screw 5 arranged on a line of rails 3 and whose absolute coordinates are X _i , Y _i , Z _i . The device 7 makes it possible to know the coordinates detected X _D , Y _D , Z _D. The encoder 9 indicates the position X ₀ of the carriage 1 which allows, firstly, to calculate the absolute coordinate X _i = X _D + X ₀ of the lag screw. Thereafter, the potentiometer 15 indicates the position longitudinal X _M of the carriage, which makes it possible to calculate the absolute position of the carriage X _M + X ₀ and to calculate the difference ΔX _i . ΔX _i is the distance that the carriage 1 must travel for the head to be positioned above the lag screw 5 and which corresponds to a signal SV _X to be sent to the solenoid valve of the jack 13 and possibly 30 to ensure the movement along X of the module. In the same way, the value Y _D is transmitted to a computer which makes it possible to calculate the difference ΔY _i taking account of the position Y _M of the module which is known since it is always the same. It is thus possible to send a signal SV _y corresponding to ΔY _i to the solenoid valve of the double-acting cylinder 20 to position the head of the lag screw along the Y axis.

The position Z _D of the module which is also constant makes it possible to calculate the value ΔZ _i which corresponds to a signal SV _Z to be sent to the solenoid valve of the jack 17 allowing the head to be lowered to the height of the lag screw 5. Finally, if necessary , the angle ϕ is introduced into a device, which makes it possible to send a signal EVϕ to the solenoid valve of the piston 33 to control the angular displacement of the drawing head.

Claims (12)

1. Process for screwing and unscrewing tie screws of a railroad according to which a vehicle (1) advancing on the railroad and carrying tie screw tightening heads (16,16a) and tie screw (7,8) detection devices is used, the vehicle (1) being displaced continuously whereas the tie screw tightening heads are displaced with respect to said vehicle by jumps from one work position to the other characterised in that the inclination of each tie screw tightening head (16, 16a), where necessary, is adjusted and in that the following steps are realised in a totally automatic manner for each tie:

   a. the relative position of each tie screw with respect to the corresponding tie screw head is determined according to the following steps:

   a1. an orthogonal reference base XYZ is defined, X being parallel to the rail axis, Y perpendicular to the previous and parallel to the tie and Z being perpendicular to the XY plane,

   a2. the relative position of the vehicle on the track is continually measured with respect to the reference base,

   a3. the relative position of each tie screw head is continually measured with respect to the vehicle,

   a4. the position of each tie screw is detected and calculated with respect to the reference base and,

   a5. the deviation in position between each tie screw and the tie screw head is calculated;

   b. each tie screw head is positioned in the XY plane in order to coincide with the exact position of a tie screw;

   c. a tie screw fastening cycle is individually started for each tie screw head comprising lowering, screwing, respectively unscrewing of the tie screws and raising.
2. Process according to claim 1, characterised by the fact that when the calculated deviations in position are equal to zero, the tie screw fastening cycle of the tie screw fastening head starts automatically.
3. Process according to one of claims 1 or 2, characterised by the fact that the values measured at steps a2, a3 and a4 are stored in a computer (8).
4. Process according to one or claims 1 to 3, characterised in that the automatic tie screw fastening cycle for screwing comprises the following steps, after the positioning of a tie screw fastening head with respect to the tie screw:

   a. longitudinal locking of the head on the corresponding rail,

   b. quick lowering toward the tie screw,

   c. introduction of the tool grasping the tie screw head,

   d. rotation of the tool,

   e. measurement of the screwing torque,

   f. automatic stop when a predetermined value of screwing torque is exceeded,

   g. release of the tool and quick raise,

   h. unlocking of the tie screw head from the corresponding rail.
5. Machine for carrying out the process according to one of claims 1 to 4, comprising a vehicle (1) provided with means enabling said vehicle to move along the track, means (7,8) for detecting et determining the relative position of a tie screw (26) with respect to a tie screw head (16, 16a), a module (10) for each rail track (3), equipped with at least one tie screw head (16, 16a), said module (10) being designed so as to be movable with respect to the vehicle (1) in the direction of the axis of the rail track (3), said tie screw head (16,16a) being provided with means (30,31,27a;17,18;20,21,22;33) for being moved with respect to the module in a first direction parallel to the axis of the rail track (3), in a second direction perpendicularly to said axis and parallel to the tie (4), in a third direction perpendicular to the plane defined by both preceding directions, and angularly with respect to said third direction, and means automatically engaging an individual tie screw fastening cycle for each head (16,16a).
6. Machine according to claim 5, characterised by the fact that it is additionally provided with means (9;7,8;15) for detecting and measuring the position of the vehicle (1) on the track, the position of the tie screw (26) and the position of the corresponding tie screw heads (16,16a) with respect to the vehicle (1) and calculating means for calculating the relative position of the tie screw heads (16,16a) with respect to the corresponding tie screws (26) and for permanently calculating the deviation between said heads and the next screw heads.
7. Machine according to one of claims 5 or 6, characterised by the fact that the automatic means engage a tie crew fastening cycle when the calculated deviations equal zero.
8. Machine according to one of claims 6 or 7, characterised by the fact that it is provided with means (8) allowing to record the position values of the vehicle (1), of the tie screw (26) and of the corresponding tie screw heads (16,16a).
9. Machine according to one of claims 5 to 8, characterised by the fact that the vehicle (1) is provided with automotive means.
10. Machine according to one of claims 5 to 9, characterised by the fact that the means allowing to displace the tie screw heads (16,16a) are hydraulic means or motors associated with screws, or a system of articulated levers.
11. Machine according to one of claims 5 to 10, characterised by the fact that the means for detecting the tie screws (26) are contactless sensors, in particular optoelectronic means (7).
12. Machine according to one of claims 5 to 11, characterised by the fact that each tie screw head (16,16a) comprises means for positioning the head with respect to the tie screw (26), means for blocking (24,25) the head with respect to the rail (3), means (17,18) for quick lowering and introduction of the tool, means (16b) for rotating, means for measuring the screwing torque, respectively the unscrewing torque, means for automatically stopping the screwing when the torque increases and means for releasing the tool.

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