EP0059500B1 - Ballast cleaning machine running on tracks - Google Patents

Abstract

1. Railway ballast cleaning machine adapted to travel on rails, with a vibrating screen arrangement (15) for cleaning the ballast, preferably with two spaced superposed perforated bottoms (40, 41), and with belt conveyors (13, 14, 28, 29) for transporting the ballast and the waste, characterized in that the vibrating screen arrangement (15) comprises at least two vibrating screens (16, 17) mounted in series and independently of each other to the machine frame (1) and each being driven by its own drive means (48, 49), said drive means are adapted to be controlled independently of each other and to be cut on and cut off successively.

Description

The present invention relates to a mobile machine on tracks, for the purification of ballast from railways, comprising a screening plant for the ballast preferably equipped with two superimposed sieves and conveyor belts for transporting the ballast and materials to be evacuated .

Machines for purifying the ballast equipped with a vibrating screen are known in many forms (for example patents CH 309 855 and CH 562 918). In these machines, the screening installation consists of an inclined vibrating screen, having two superimposed sieves of different mesh size, driven in vibration by a flywheel, the refined ballast, ready to be reused, accumulating on the lower sieve for then be conveyed, by means of a conveyor belt, to the places of repositioning, the excessively large materials remaining on the upper screen, while the too small materials pass through the lower screen and are evacuated to be discharged.

These vibrating screens have relatively large dimensions longitudinally in order to have a screening path long enough to ensure total purification. The large dimensions of the screen and the high weight of the screen fully loaded with ballast, however, have the disadvantage that it is necessary to accelerate and move very large masses. The amplitude of oscillation and the frequency of oscillation of the screen, which essentially determine the screening capacity, can only be chosen as high as the stability and resistance of the machine frame to the forces developed by the masses allow. driven in vibration. The stresses developed during the start-up of the loaded screen and at the time of its stop, after the triggering of the drive motor, until stop, proved to be particularly critical. The start-up time and the stop time of a loaded screen is of the order of 30 seconds or more. Whenever the sewage treatment machine or wagon, which normally advances continuously, must be stopped for some reason, the vibrating screen must be triggered and must not be re-engaged until the machine resumes its lead. The above-mentioned stresses on the machine frame during start-up and stop of the loaded screen can therefore appear relatively frequently.

Known vibrating screens have a typical capacity of about 800 m ³ / h, the screen drive motor rotating at a speed of about 100 rpm corresponding to an oscillation frequency of about 100 Hz, l maximum authorized amplitude of oscillation being of the order of 12 mm. As the amplitude of oscillation and the frequency of oscillation cannot be increased, for reasons of permissible load on the machine, it is not possible to increase the capacity of the machine without further although this is desirable for achieve as high a working speed as possible.

The present invention aims to achieve a screening installation having a more favorable operation making it possible to achieve a greater capacity and a more flexible adaptation of the factors determining the purification and the transport of the ballast to the working conditions and making it possible to reduce the stresses of the machine frame.

To this end, the machine according to the invention is characterized in that the screening installation comprises at least two vibrating screens mounted one behind the other and independently of one another on the frame of the machine, each being driven by its own drive device, these drive devices being controllable independently of one another and being able to be engaged and triggered one after the other.

It is thus possible to reduce the accelerated masses and driven in vibration simultaneously and synchronously, in particular to reduce these masses approximately by half by using two vibrating screens mounted one behind the other, advantageous solution on the technical and economic plan. , so that the forces required to drive each of the screens, and above all the vibrations transmitted by each of the screens to the machine, are significantly reduced. It is therefore possible to train smaller screens with higher amplitudes and / or frequencies of oscillation and thus obtain a screening plant with a higher yield than machines with a single large screen.

In particular, the instants of engagement and of triggering, the frequencies and / or the amplitudes of oscillations of the screens, as well as their inclinations can be chosen individually and in a differentiated manner for each screen so as to be adapted to the working conditions of each of the screens. In the event of a temporary shutdown of a machine with two screens, it is in particular possible to stop the first screen first, then the second after a certain time, and to restart the second first. screen, then the first after a certain time, the critical stresses of the machine during these periods of stopping and restarting being thus significantly reduced. The invention further makes it possible to lower the requirements as regards the stability and the resistance of the machine to vibrations, which corresponds to a general tendency to build machines as light as possible.

The screening installation is advantageously carried out in such a way that the end of the screens, exit side, of the first screen covers the end, entry side, of the screens of the second screen, respectively of the following screen, so the ballast leaving the first screen falls directly on the second screen, respectively the next screen.

• La figure 1 est une vue latérale de la machine.
• La figure 2 est une vue de détail, schématique, de l'installation de criblage à deux cribles vibrants.
• La figure 3 est une vue de dessus de l'installation de criblage, la moitié supérieure de la figure représentant les tamis inférieurs et la moitié inférieure de la figure les tamis supérieurs.
• La figure 4 est une vue frontale de l'installation de criblage selon la flèche IV, figure 2.

The accompanying drawing shows, by way of example, an embodiment of the machine according to the invention.

• Figure 1 is a side view of the machine.
• Figure 2 is a detailed schematic view of the screening plant with two vibrating screens.
• Figure 3 is a top view of the screening plant, the upper half of the figure showing the lower screens and the lower half of the figure the upper screens.
• FIG. 4 is a front view of the screening installation according to arrow IV, FIG. 2.

The machine moving in the direction of the arrow, FIG. 1, comprises a front chassis 1 provided with two bogies 3 and 4 and a rear chassis 2 connected at its front end to the chassis 1 by an articulation 9. The boggies 3 and 4 of the chassis 1 rest on track 6, in front of the working place proper, tracks which are fixed in a well-known manner on crosspieces 7 resting on the ballast 8, while the bogie 5 of the rear chassis rolls on the track back of the workplace.

On the rear frame 2 is mounted an excavator chain 10 for removing the ballast, which has, seen from above, a known trajectory of approximately triangular shape and a section 11 passing transversely under the tracks 6 and the crosspieces 7. The two sections ascending of the excavating chain 10 pass over a hopper 12 in which the ballast is discharged and through which it falls on a conveyor belt 13, which leads the ballast to be purified in the direction of movement of the machine all first in an oblique upward movement then horizontally on another conveyor belt 14 which brings the ballast to the purification installation.

The purification installation consists of a screening installation 15 mounted on the chassis 1 and equipped with two vibrating screens 16 and 17, mounted one behind the other, inclined in the opposite direction to the direction of advance of the machine and which are mounted on vertical supports 18, 19 and 20 by means of helical springs 21, 22 and the construction of which will be described in more detail with reference to FIGS. 2 to 4. The conveyor belt 14 extends to the above the screening installation 15 up to the entry of the latter at the upper end of the first screen 16, so that the ballast falls first in the first screen 16 and then passes into the second screen 17. The two vibrating screens 16 and 17 have, in a manner known per se, two superimposed sieves of different mesh size, so that the refined ballast, ready to be reused, accumulates on the lower sieve of where it is discharged on a conveyor belt 23 to the delivery means in place. The materials of too large dimension which do not pass through the upper sieve, as well as the materials of too small dimension and the detritus having crossed the two sieves end up on a conveyor belt of evacuation 28 located under the screening plant 15, which unload on another conveyor belt 29 which discharges them towards the front of the machine, where they are either unloaded in a wagon or on the side of the track.

The clean ballast transported by the conveyor belt 23 in the opposite direction to the direction of movement of the machine is brought into the zone of the excavator chain 12 where it falls on a distribution device 24. A part of this ballast is discharged onto the track by a hopper 25 of the device 24, immediately behind the place where the excavator works, indicated by P1 in FIG. 1, to replace the removed ballast. It is then and immediately flattened and compacted by means of a device 30. The remaining ballast is discharged by a second hopper 26 from the device 24 on a dispensing tape 27 which can pivot transversely around its anterior end, in a known manner, which transports the ballast one end towards the rear of the machine where it discharges onto the already worked ballast, at location P2, essentially on each side. Instead of a single dispenser tape 27, it is possible to provide two dispenser tapes on each side of the machine. The distribution device 24 is equipped with a controlled distribution member, for example a valve, by means of which a determined part of the purified ballast, corresponding to the depth of excavation and to the desired height of the new ballast, is deflected in the hopper 25, while the rest of the ballast flows into hopper 26.

A track lifting device 31, known per se, fixed to the chassis 2, immediately in front of the excavation location, is arranged to lift the rails 6 with their cross members 7 if necessary, to allow the excavator chain 10 to work in the shallow excavation. Known lifting devices 32 make it possible to adjust the working height of the excavator chain 10.

The construction and arrangement of the two vibrating screens 16 and 17 are shown in more detail, but diagrammatically in FIGS. 2 to 4. According to FIG. 2, in which the upper conveyor belt 14 and the lower discharge ribbon 28 are also represented, the ballast to be purified falls from the conveyor tape 14 in the direction of the curved arrow in the entrance of the screen at the left end of the drawing. The first screen 16, which has an upper screen 40 and a lower screen 41, is not located exactly in line with the second screen 17, provided with an upper screen 42 and a lower screen 43, but it is slightly vertically offset relative to the second screen 17, so that the outlet of the first screen 16, that is to say the edges of the screens 40 and 41, covers slightly and respectively the upper ends of the screens 42 and 43 of the screen 17, with a clearance of course sufficient so that the two screens do not come into contact when they vibrate, the ballast leaves both the screens 40 and 41 thus directly falling on the screens 42 and 43 respectively. The two vibrating screens 16 and 17 are supported on each side, freely oscillating, by helical springs 21, respectively 22 supported themselves by the supports 18, 19 and 20. Instead of helical springs it is possible to use blocks rubber. The front support 18 and the rear support 20 are equipped with lifting devices 52, respectively 53 allowing their height to be modified and therefore the individual inclination of each of the screens 16 and 17, acting on their opposite ends, the height of the superimposed ends of the two screens being fixed.

The side walls of each screen 16 and 17 are crossed, approximately in the middle, by a shaft 44, respectively 45, the ends of which carry an unbalance 46, respectively 47, driven in rotation by a motor 48, respectively 49 via a belt 50, respectively 51.

FIG. 3 represents, in its lower half, a top view of the upper screens 41 and 42 and in its upper half a view of the lower screens 41 and 42. The screens are covered by an extension 40a, 41a respectively, of the screen proper 40, respectively 41. Baffle plates 54 of the upper screen 42 of the screen 17 (fig. 3 and 4) deflects aside the materials too large to be evacuated, so that they can fall, on each side of the zone median occupied by the outlet of the lower screen 43, on the evacuation conveyor belt 28, onto which also fall the materials having passed through the lower screens 41 and 43. The lower screen 43 of the screen 17 has at its end on the outlet side a deflector plate 55 directed inwards, which directs the ballast to be reused towards a hopper 56 by which it falls on the conveyor belt 23, as shown diagrammatically in FIG. 2. As can be seen from FIGS. 3 and 4, the width of the hopper 56 mounted in the central area of the screen outlet is less than the width of the upper screen 42 by a value such that the large waste discharged from the upper screen can fall on each side of the hopper 56 onto the conveyor belt. evacuation 28.

In FIG. 4, which shows a front view, on the outlet side, of the screen, the conveyor belt 14, the discharge ribbon 28, the screen drive motors 48 and 49, as well as the supports 18, 19 and 20 n have not been represented. The drive belts 51 and 52, driving the shafts 44 and 45, are shown in section. In the upper part of this figure 4 there is the upper screen 40 of the screen 16, below it the upper screen 42 of the screen 17 and lower, at the hopper 56, the lower screen 43 of the screen 17 .

- The arrangement of the screens has the advantage that each of the screens 16 and 17 can be driven individually and in that for each of the screens relatively small masses must be accelerated and kept in motion. Individual training by means of two independent motors 48 and 49 practically excludes a synchronous vibration of the two screens 16 and 17, so that in general the forces generated by each of the screens on the frame 1 of the machine more or less neutralize each other. less, advantageously. The arrangement has in particular the advantage of making it possible to control the two vibrating screens separately, so that during startup, it is possible to switch on first the second screen 17, then, after a certain time, for example about 30 seconds, to switch on the first screen 16. Conversely, when the machine has to be stopped, the first screen 16 is stopped, then after a certain time, for example about 30 seconds, the second screen 17 is stopped in turn. In both cases the masses to be accelerated, respectively to be braked, are half as large as in known installations comprising a single screen, which is particularly important when the screens are working at full load. Chassis stresses are reduced. On the other hand, two smaller and lighter screens can work with larger amplitudes of oscillation and / or a higher oscillation frequency than a single screen with a corresponding load. Until now, the maximum amplitude of oscillation has generally been of the order of 12 mm, whereas it may be of the order of 16 mm with the installation according to the invention. It is thus possible to reach a screening yield of the order of 1000 m ³ / h whereas this yield was previously of the order of 800 m ³ / h.

In addition, the two screens 16 and 17 of the installation according to the invention can be, if necessary, driven at different frequencies and / or with different amplitudes. It is also possible, if necessary, to give a different inclination to each of the screens 16 and 17. The screening installation according to the invention therefore not only makes it possible to build vibrating screens smaller than hitherto, but also allows individual screen training, both in terms of frequency and amplitude of oscillation and inclination, depending on the nature of the ballast to be cleaned and the working conditions, which allows optimum performance to be achieved.

The invention is not limited to the embodiment shown, but extends to many variants, as regards the execution and the arrangement of the vibrating screens. These can in particular have more than two superimposed sieves. It is also possible to provide more than two screens mounted one behind the other, but it seems that two screens are sufficient, for practical and economic reasons, to obtain the desired advantages.

Claims (5)

1. Railway ballast cleaning machine adapted to travel on rails, with a vibrating screen arrangement (15) for cleaning the ballast, preferably with two spaced superposed perforated bottoms (40, 41), and with belt conveyors (13, 14, 28, 29) for transporting the ballast and the waste, characterized in that the vibrating screen arrangement (15) comprises at least two vibrating screens (16, 17) mounted in series and independently of each other to the machine frame (1) and each being driven by its own drive means (48, 49), said drive means are adapted to be controlled independently of each other and to be cut on and cut off successively.

2. Machine according to claim 1, characterized in that the outlet end of the perforated bottom or bottoms (40, 41) of one vibrating screen (16) overlaps the inlet end of the perforated bottom or bottoms (42, 43) of the following vibrating screen (17).

3. Machine according to claim 1 or 2, characterized in that lifting devices (52, 53) for the separate adjustment of the slope of each vibrating screen (16, 17) are provided.

4. Machine according to any of claims 1 to 3, characterized in that the vibrating screens (16, 17) are operable with different vibration amplitudes and/or different vibration frequencies.

5. Machine according to any of claims 1 to 4, comprising two vibrating screens mounted in series, characterized in that a lifting device (52) for the first vibrating screen (16) is disposed in the area of its inlet end and that a lifting device (53) for the second vibrating screen (17) is disposed in the area of its outlet end.

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