EP0125348A1 - Machine for reprofiling rail heads - Google Patents

Abstract

This machine comprises at least one grinding unit mounted to a grinding base. Each unit comprises a frame secured to the grinding base. The grinding wheel is driven by an electric motor, suspended from the frame by means of four rocker arms constituting two parallel-motion suspension systems. The lower rocker arms are levers of the first order and the grinding pressure is applied for one of the rocker arms by the piston rod of a hydraulic cylinder rigid with the frame and adapted to position the grinding wheel in relation to the rail, and for the other rocker arm by the piston rod of a pneumatic cylinder also rigid with the frame. This pneumatic cylinder determines the operating pressure of the grinding wheel on the rail. The operative face of the grinding wheel is parallel to the plane of the theoretical tangent to the rail profile. A right-angled lever is pivoted to a projection of the frame and provided at one end with a stud facing the grinding wheel. During the forward feed of the grinding wheel this stud moves from an inoperative position to the theoretical tangent and when this theoretical tangent is attained by the wheel the opposite end of the right-angled lever actuates a device for stopping and locking the feed of the grinding wheel by actuating the hydraulic positioning cylinder.

Description

The present invention relates to a machine for reprofiling the head of the rails comprising one or more grinding heads per line of rails of the means for positioning and advancing the cutting tool (s) on the mushroom, the grinding head (s) being arranged around the mushroom so as to create one or more facets determined by the theoretical tangents along one, respectively several, generating the theoretical profile of the mushroom.

To reprofile the railway rails deformed by traffic, it is necessary on the one hand to eliminate the undulations created on the running surface and on the other hand to remove the beads created on either side of the mushroom. To reprofile the running surface, grinding machines and deburring machines are used to remove the beads. The trimmers fitted with inclined grinding wheels remove a quantity of material on each pass depending on the bearing force applied to them.

To obtain a precise reprofiling, it is necessary to guide and position the grinding wheel with respect to the axis, the rolling plane P1 (fig. 1) and the inner lateral face P2 of the rail so that the theoretical tangent T to the desired profile (theoretical) can be obtained. Of course, for the complete reprofiling of the fungus, several grinding wheels are used which are inclined at different angles in a plane transverse to the track, which must be guided to obtain a multitude of facets respectively determining the theoretical tangents Ti, T2, T3, etc. along generators Gl, G2, G3 etc. of the fungus.

Such a machine is described in CH-A-633.336. A rail head grinding vehicle is equipped with two groups of grinding heads per rail row. Each group includes four grinding heads forming a grinding shoe suspended from the vehicle chassis. Two pads facing each other, one per row of rails, are connected by their middle part to a connecting element. Each shoe is angularly movable in a transverse plane of the track in order to allow the orientation of the grinding heads to be modified and thus to be able to correct the whole of the fungus in several passages. According to a variant each grinding head is provided with means allowing its individual pivoting with respect to the other grinding wheels of the grinding shoe and parallel to a transverse plane of the track, thus increasing the possibilities of approaching the profile of the mushroom. Means for changing the inclination of the skids and / or heads of step-by-step grinding is planned. A jack and two drawbars articulated to a console fixed under the chassis of the vehicle ensure the suspension of each grinding pad, the jack ensuring on the one hand the lifting of the pad for walking high and on the other hand the adjustment of the support pressure of the skate on the line of rails. Each grinding head can be individually adjusted in height with respect to the grinding pad by means of a slide.

The possibilities of adjusting the inclination of the skate as well as the adjustment of the inclination. of each grinding head relative to the shoe allow an optimal approach to the theoretical curve of the profile "of the fungus. The set of grinding heads forming the same shoe are applied integrally on the rail without having the possibility of individually controlling the advance of each grinding wheel, which can, of course, be positioned in height in relation to the other grinding wheels. This positioning takes place by means of a screw controlled by a handwheel before the start of grinding and cannot be changed during the advance On the other hand, no means of controlling the positioning of the shoe is described except the lifting cylinder which is also used to adjust the bearing force of the shoe on the rail. The shoe system is satisfactory if the generators are relatively tight. In this case, the ripples are eliminated according to the length of the shoe, that is to say the extreme distance between the grinding heads. In the case where the generators are spread apart, the cont working role proves difficult and the grindstones tend to copy the undulations on the burrs, because the skate is no longer guided.

_CH -A-614 _- 476 also describes a machine for grinding the running surface of the rails, comprising a device for controlling the advance of the controlled cutting tool as a function of the dimensions of the corrugation and of the wear. of the tool, but not according to the theoretical tangent to the profile of the mushroom.

The present invention aims to overcome these drawbacks by proposing a machine avoiding grinding of the profile of the fungus beyond the theoretical tangent to the desired profile (theoretical).

The machine according to the invention is characterized in that each grinding head comprises a member located in the plane of the facet or in a parallel plane detecting the arrival of the cutting tool in the plane of the theoretical tangent and controlling the blocking of the means of positioning and advancing the cutting tool against the fungus as soon as the plane of the theoretical tangent is reached.

The advantages obtained thanks to the invention consist in that the cutting tool cannot advance beyond the plane of the predetermined theoretical tangent which avoids too deep grinding or partial grinding and makes it possible to obtain an optimal approach of the profile. A tilting mechanical stop can be placed facing the cutting tool - and at the end of its tilting, under the action of the advance of the tool, the advance of the grinding head is blocked, the position of the stop being such that at the end of its tilting the active face of the cutting tool has reached the plane of the theoretical tangent. The stop acts directly or indirectly through a proximity sensor, on a valve hydraulic or pneumatic supply circuit of a positioning cylinder.

Alternatively, instead of a mechanical stop, a pneumatic sensor can be used, the air jet of which is placed on the theoretical tangent and as soon as the cutting tool arrives in front of the orifice through which the air exits it disturbs the air jet, this disturbance being detected the blocking valve of the positioning cylinder is actuated.

The grinding heads are mainly used grouped and connected to a grinding base guided on the one hand in the vertical median plane of the rail, that is to say the longitudinal plane which passes through the axis of symmetry of the transverse profile of the rail. , and on the other hand in height by pressing on the surface of the rails, for example by means of rollers or pads. The grinding heads depending on this base are inclined at different angles in a plane transverse to the rails, that is to say perpendicular to the longitudinal direction of the rails.

According to a variant, the angle of inclination of each head can be modified, either step by step between two predetermined limit values, or take one or the other of two predetermined values.

• La figure 1 représente une coupe transversale du champignon d'un rail déformé.
• La figure 2 représente une vue de côté d'une tête de meulage selon la ligne II-II de la figure 3
• La figure 2a représente une variante d'un détail de la figure 2.
• La figure 3 représente une vue de la tête de meulage selon la ligne III-III de la figure 2.
• La figure 4 est une vue schématique latérale d'une base de meulage, les têtes étant montées solidaires les unes des autres.
• La figure 5 est une vue analogue à la figure 4 d'une base de meulage dont l'inclinaison de chaque tête de meulage peut être modifiée indépendamment des autres.
• La figure 6 est une vue schématique de front d'une base de meulage présentant le dispositif pour faire varier l'inclinaison, certaines parties ayant été omises pour plus de clarté.
• La figure 7 est une vue partielle d'un profil de rail avec indication des centres et des rayons de courbure.

According to another variant, the modification of the angle of inclination of each head takes place independently of the other heads and according to yet another variant, the heads of a grinding base are mounted integral with one another so that the modification the angle of inclination operates simultaneously for all heads, the relative angles between the remaining heads always the same.

• Figure 1 shows a cross section of the mushroom of a deformed rail.
• Figure 2 shows a side view of a grinding head along line II-II of Figure 3
• FIG. 2a represents a variant of a detail of FIG. 2.
• FIG. 3 represents a view of the grinding head according to line III-III of FIG. 2.
• Figure 4 is a schematic side view of a grinding base, the heads being mounted integral with each other.
• Figure 5 is a view similar to Figure 4 of a grinding base, the inclination of each grinding head can be changed independently of the others.
• Figure 6 is a schematic front view of a grinding base showing the device for varying the inclination, some parts having been omitted for clarity.
• Figure 7 is a partial view of a rail profile showing the centers and radii of curvature.

Each grinding head (fig. 2,3) comprises a frame ₁ provided with two pairs of orifices 27a, 27b by which is fixed to a grinding base installed on a grinding vehicle, an electric motor 2 carrying the tool cut in the form of a grinding wheel 3 driven by through the spindle 4 and suspended from the frame 1 by four pendulums 5,6,7,8 forming two suspension parallelograms 5, and 7,8. The pendulums 5 and 7 are articulated on one side on an axis 9 secured to the chassis 1 and on the other hand on the motor cage 2 by articulations 5a respectively 7a. The pendulums 6,8 which are in fact levers of the first kind, are articulated by an intermediate point to an axis 10 secured to the chassis 1 and by one of their ends 6a respectively 8a to the motor cage 2. The second end of the lever 8 applies or abuts the rod 11 of a jack 12, preferably hydraulic, secured to the chassis 1, while the second end of the lever 8 is articulated to the rod 13 of a jack 14, preferably pneumatic, suspended by an articulation 15 to a projection 1a of the chassis 1. The jack 11 is the jack for positioning the grinding wheel while the jack 14 is the grinding jack, that is to say the one which regulates the bearing force of the tool on the rail. Of course it would be possible to replace the two cylinders with a single one, nevertheless, for precise positioning it is better to use a hydraulic cylinder whose function is only the positioning and not the adjustment of the pressing force.

On a projection 16 of the frame parallel to the lateral surface of the grinding wheel 3 is articulated around an axis 17a a lever bent 17 from the inside of the angle, so that its end 18 is disposed facing the peripheral part of the active surface of the grinding wheel 3. This end 18 is provided with a lug 19 of a material having a greater abrasion resistance than that of the grinding wheel 3. The second end 20 of the lever 17 has an approximately perpendicular projection to the arm of the adjacent lever which is subjected to the force of a spring 21 which causes the lever 17 to tilt so that the lug 19 is in the rest position in the plane A (dotted line) held against a stop not illustrated. The projection of the end 20, when the lever pushed by the grinding wheel 3 is tilted clockwise, abuts against a valve 22 controlling the hydraulic circuit of the cylinder 12 thus blocking the stroke of the rod 11 and consequently the advance of the grinding wheel 3. Between the moment when the grinding wheel 3 comes into contact with the lug 19 and the moment when the valve? 2 is actuated the grinding wheel advances by a distance D. At the end of the tilting of the lever 17 the end of the lug 19 and consequently the active surface of the grinding wheel 3 is on the theoretical tangent T to the theoretical profile of the head of the rail 23.

According to a variant, the valve 22 can be replaced by a proximity detector detecting the approach of the end 20 of the lever and controlling by an electro-hydraulic or electro-pneumatic circuit the blocking of the supply to the cylinder of the jack 12.

According to a third variant illustrated in FIG. 2a, instead of the tilting lever 17, it is possible to use a proximity detector 24, in particular a pneumatic detector. In this case, the pneumatic detector 24 sends by a nozzle a jet of compressed air parallel to the active surface of the grinding wheel 3, the nozzle being placed exactly on the theoretical tangent T. When the lateral surface of the grinding wheel 3 approaches the nozzle disturbs the air jet and this disturbance being detected an electro-hydraulic or electro-pneumatic circuit acts as previously on the positioning cylinder 12.

It is obvious that the reprofiling of the rails is not rational with a single wheel per row of rails. Usually several grinding wheels are grouped by fixing them at a different inclination on a grinding base provided with pads or rollers to be guided relative to the median plane of the rail.

In FIG. 4, there is shown quite schematically a grinding base 25 comprising three grinding heads referenced 26, a grinding head 26 corresponds to a unit shown in FIGS. 1 and 2.

The three grinding heads 26 are secured to each other by rods 27 'while the heads situated at the ends are fixed to the base 25 by guide rods 27 fixed to the orifices 27a and 27b of their respective chassis 1 (FIG. 2 + 3). Each grinding head is fixed at a different inclination from the others so in a single pass the rail head is reprofiled according to three generators G1, G2, G3 (fig.1) by creating tangential facets containing the corresponding theoretical tangents Tl, T2 respectively , T3. If the theoretical tangents are not reached in a single pass, a second or even several passages are carried out until the desired profile is obtained. The chassis 28 of the base 25 rests by two legs 29.30 provided with two pads 31 on the rail rolling surface 23. It is suspended by two double-acting cylinders 32 ensuring on the one hand the withdrawal of the base 25 for walking high and on the other hand the permanent contact of the pads 31 with the rails during grinding. Furthermore, as shown by the embodiment according to FIGS. 5 and 6, the pads 31 can be replaced by rollers 35. Cylinders, such as those referenced 33 in Figure 6, provide guidance in the horizontal plane of the base 25 by pressing rollers 34 against the inner side surface of the mushroom.

The grinding heads 26 can either be mounted on the frame 28 with an invariable inclination with respect to each other (fig.4) and in this case there are two possibilities 1) the angle of inclination of the heads cannot be modified, 2) it is possible to modify the angle of inclination of heads in block, or it is possible to modify the inclination of each head independently of the other heads between two limit values, as shown in FIG. 5 which will be described later.

• i) Si les têtes sont montées de sorte que l'inclinaison relative entre elles ne peut pas être modifiée, comme représenté à la figure 4, alors la variation de l'inclinaison de l'ensemble de têtes de la base est telle que les trois têtes restent toujours à l'intérieur de l'arc A1, ou A2 ouA3. Dans ce cas la première tête est disposée de sorte qu'elle reste à l'intérieur de l'arc A'1, respectivement _A'2 respectivement A'3, la deuxième à l'intérieur de l'arc A"1, respectivement A"2, respectivement A"3 et la troisième à l'intérieur de l'arc A"'1, respectivement A"'2, respectivement A"'3.
• ii) Si les têtes sont montées de sorte que l'inclinaison relative entre elles peut varier, comme représenté à la figure 5, alors deux possibilités existent:
  • a) La première tête reste à l'intérieur de l'arc A1, la deuxième à l'intérieur de l'arc A2 et la troisième à l'intérieur de l'arc A3, lors de la modification de leur inclinaison.
  • b) L'inclinaison de chaque tête peut varier à l'intérieur de la totalité de l'arc A1+A2+A3.

To modify the angle of inclination of the heads of a base individually or as a block, it must be done by taking the precaution of placing the active face of the cutting tool parallel to the theoretical tangent plane to the theoretical profile of the rail. For clarity, FIG. 7 shows half of a theoretical profile of a rail. We can consider that half of the profile of the upper part of the head of a rail 23 is obtained by the connection of three arcs of circle whose angular measurement is respectively A1, A2, A3 centered at the points C1, _C2 , C3. To obtain a correct reprofiling of the mushroom a grinding head must be guided when changing the angle of inclination so that two fixed points of the head defining a straight line parallel to the drive spindle of the cutting tool move on two trajectories homothetic to the curve of the profile of the fungus. We have represented in FIG. 7 these trajectories by the dotted lines 40a and 41a without respecting the proportions between the dimensions of the profile of the rail 23 and the actual distance both between these paths and between the rail 23 and the paths 40a and 41a. It is obvious that the quality of the profiling work is proportional to the number of facets created. Theoretically we can use a single grinding head to create several facets approaching the theoretical profile of the fungus. In this case the inclination of the head can be changed as many times as desired from one end to the other of the profile, taking the precaution of guiding two fixed points of the head as mentioned previously on two trajectories 40a and 41a. The use of a single head is not rational we use, as already mentioned, bases each of which is provided with at least two heads and in the present case we have chosen by way of example a base with three heads (fig. 4 and 6). The possibilities of modifying the inclination of the heads of a base are the following:

• i) If the heads are mounted so that the relative inclination between them cannot be modified, as shown in Figure 4, then the variation of the inclination of the set of heads of the base is such that the three heads always remain inside arc A1, or A2 or A3. In this case the first head is arranged so that it remains inside the arc A'1, respectively _A '2 respectively A'3, the second inside the arc A "1, respectively A "2, respectively A" 3 and the third inside the arc A "'1, respectively A"' 2, respectively A "'3.
• ii) If the heads are mounted so that the relative inclination between them may vary, as shown in Figure 5, then two possibilities exist:
  • a) The first head remains inside the arc A1, the second inside the arc A2 and the third inside the arc A3, when changing their inclination.
  • b) The inclination of each head can vary within the entire arc A1 + A2 + A3.

In FIG. 6 we have shown the means by which the angle of inclination of a grinding head or of multiple heads can be varied, as shown in FIG. 4, mounted on a grinding base. It is a front view corresponding to FIG. 5, certain parts having been omitted. The base shown in Figure 5 has the difference from that of Figure 4 the fact that the heads are mounted so that one can change their angle of inclination independently of one another. In addition, the shoe 31 has been replaced by a roller 35. The same references followed by a zero have been used for the elements of FIG. 5 corresponding to FIG. ₄ .

Before describing the fixing of the grinding heads we will describe the means to vary the inclination of a head shown in Figure 6. The chassis 280 rests on the running surface of the rail 23 by rollers 35 and it is guided horizontally by jacks 330 and rollers 340. The chassis 280 is composed of two tubular beams 36 and 37 fitted with sheets having a triangular section seen from the front. In order to be able to modify the inclination of a grinding head 260, the rods 270 have been mounted on a pendulum 38 (in dotted lines) suspended from the chassis 280 of the grinding base 250 by a jack 39. Both rods 270 are guided in two circular grooves 40, 41 corresponding to the lines 40a and 41a of FIG. 7. The grooves 40 and 41 are arcs of a circle centered at point 0'1 which is the center of curvature of an arc of a circle of the profile of the mushroom delimited by the two tangents T'1 and T'2 forming an angle B'1 which corresponds to the angle between the two extreme positions of the grinding head, the angle being of the order for example of 10.

The grooves 40 and 41 may correspond to one of the arcs A1, A2, A3 in FIG. 7 of the lines 40a and 41a or to the whole of the arc A1 + _A 2 + A3. In the case of the base shown in Figure 4 the heads 2G must remain inside one of the arcs A1, A2 or A3 as mentioned above and in this case the grooves ₄ 0 and 41 correspond to a portion of the 'one of these arcs so that the heads remain respectively inside arcs A'1, A "1, A"' 1 or A'2, A "2, A"'3 or A'3, A "3, A"'3. The heads 26 being integral with one another the fixing rods 27 of the two heads 26 situated at the ends are guided in grooves 40 and 41 and supported by a pendulum 38 and a jack 39 as shown in FIG. 6.

In the case of the base shown in Figure 5 each head 260 is suspended from the frame 280 of the base 250 by a device similar to that shown in Figure 6. Thus each head 260 is suspended by rods 270 collaborating with grooves which they are provided with plates 43, 44, 45, 46 fixed to the frame 280 as shown in FIG. 6. Two plates which will be called 42 and 47 are fixed behind the legs 290 respectively 300 of the base 250. The grooves of each pair of plates 42, 43 or 44, 45 or 46.47 correspond respectively to one of the arcs A1, A2, _A3 (fig. 7) or to all of the arcs A1 + A2 + A3. The guide rods ₂₇₀ are connected by pendulums ₃₈ suspended and driven by jacks 39 not shown.

The modification of the inclination of a grinding head (fig. 5) or of a set of heads (fig. 4) between two limit values can be carried out either by modifying the inclination step by step, the drive being controlled for example by a motor, or by having the possibility of giving the inclination two determined values. By way of example for the latter case, a base like that shown in FIG. 4 can be considered, the inclination of the heads of which is 70, 50 and 40 respectively and after modification of the angle by means, for example, of the device. in Figure 6 the respective inclination of the heads is 60, 40 and 30.

In summary, a grinding base can be composed of one or more grinding heads and in the case of a base with several heads the angle of inclination can either be modified as a block for all the heads or independently of one of the another, that is to say the heads are mounted fixed on the grinding base at a determined inclination.

Claims (8)

1. Machine for the reprofiling of the rail head comprising one or more grinding heads per line of rails, means for positioning and advancing cutting tools on the head, the grinding head or heads being arranged around the head so as to create one or more facets determined by the theoretical tangents along respectively a plurality of generators of the theoretical profile of the fungus, characterized in that each grinding head comprises a member located in the plane of the facet or in a parallel plane detecting the arrival of the cutting tool in the plane of the theoretical tangent and controlling the blocking of the means for positioning and advancing the cutting tool against the fungus as soon as the plane of the theoretical tangent is reached. 2. Machine according to claim 1, characterized in that the member detecting that the plane of the theoretical tangent is reached comprising a mechanical stop to be moved under the action of the cutting tool preferably from a rest position and controlling the blocking of the cutting tool advance as soon as the tangent plane is reached. 3. Machine according to claim 2, characterized in that the mechanical stop acts mechanically on a hydraulic or pneumatic valve blocking the positioning and advancing means. 4. Machine according to claim 2, characterized in that a proximity detector is associated with the mechanical stop, detecting the position of the stop when the plane of the theoretical tangent is reached and controlling a hydraulic or pneumatic valve blocking the positioning and advancing means. 5. Machine according to claim 1, characterized in that the means detecting that the plane of the theoretical tangent is reached comprise a pneumatic detector controlling a pneumatic or hydraulic valve blocking the positioning and advancing means. 6. Machine according to one of claims 1 to 5, characterized in that one or more grinding heads are mounted on a grinding base, the active face of the cutting tool of each grinding head being arranged in parallel to a plane with a different theoretical tangent, and that the grinding base is provided with guide means parallel to the axis of the rails and to the vertical median plane of the rail. 7. Machine according to claim 6, characterized by the fact that the grinding base comprises several heads mounted integral with each other the angle of inclination of each head being different from the other and that the base is provided with means, in particular of plates provided with guide grooves, for varying the inclination of the assembly of the heads relative to a plane transverse to the rail around a determined center of curvature of the theoretical profile of the mushroom thus allowing the successive formation of two or more facets approaching the arc of a circle corresponding to said center of curvature. 8. Machine according to claim 6, characterized in that the grinding base comprises several heads of molding mounted on the base independently of each other and that each head is provided with means for varying its angle of inclination in a plane transverse to the rail around one or more centers of curvature of the arcs of circle constituting the rail profile.

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