The present invention concerns a machine for reconditioning railway roadbeds.

As is well-known, machines exist for reconditioning railway roadbeds, comprising an equipped wagon provided with means of temporarily lifting the track of the roadbed under the wagon, and excavation means for removing the ballast of the roadbed under the raised track. This removed ballast is conveyed to screening means to be partially recovered and returned to the reconditioned roadbed. In these machines, the excavating means, usually fitted with an excavating chain, pass under the sleepers for their entire length. The overall width of the excavating chain is somewhat greater, on both sides, than the length of the sleepers and therefore these machines cannot be used where any obstacle, natural or due to construction works, limits the free transverse section of the roadbed, on one or both sides in proximity to the edge of the heads of the sleepers, for example in tunnels, between platforms in stations, on certain bridges and so forth.

In Italian patent no. 948861 a machine is described for reconditioning railway roadbeds which, besides the means described above, also comprises means for rotating the sleepers, at least partly liberated from the rails, means for passing these sleepers in an oblique position through the gap free of the excavating chain, and means for rotating the sleepers again to their position perpendicular to the rails.

By means of such a machine described in that patent, it is possible to operate even where there are obstacles, natural and otherwise, which limit the free transverse section of the roadbed.

However, in reconditioning a railway roadbed, there is often the need to lower the level of the roadbed itself, for example where the tracks run in tunnels. This lowering of the roadbed is necessitated in order to allow particularly bulky railway wagons to pass, for example goods wagons. With the machines described above it is not possible, in the process of reconditioning the roadbed, to also carry out a lowering of the roadbed itself. In addition, the means of lifting and rotating the sleepers described in the aforementioned patent, which substantially comprise bogies running on axles, are very complex and inefficient.

From GB 2 247 265 A a machine for reconditioning railway roadbeds is known, comprising:

• an equipped wagon provided with means suitable for temporarily lifting the rails of a track,
• excavation means suitable for removing the material of the roadbed and
• means of lifting and rotating at least one sleepers to be released from the rails of the track.

However, this known machine is not provided with a unit for demolishing the roadbed.

From DE 43 29 277 A1 an apparatus for loosening and compacting the ballast of track installations by means of vibrating picks is known. This know machine does not incorporate lifting means for both rails and sleepers, nor is it equipped with means for removing the ballast from the trackbed.

The object of the present invention is therefore the creation of a machine for reconditioning railway roadbeds which allows the performance of special jobs, such as the lowering of the roadbed which is necessary in some cases inside railway tunnels, including in the presence of any rocky layers lying under the ballast, or other normal material for making the roadbed. By means of the present machine, furthermore, it is possible rapidly and efficiently to lift and rotate the sleepers in synergy with the jobs of excavating and lowering the roadbed.

This object is achieved by the present invention by means of a machine for reconditioning railway roadbeds according to what is claimed in Claim 1.

Other important aspects of the present machine are stated in the dependent claims.

Further characteristics and advantages of the present invention will become better understood in the course of the following description, considered in exemplary and non-limiting terms and referring to the attached drawings, in which:

• Fig. 1 shows a first view in lateral elevation of a machine for reconditioning railway roadbeds according to the present invention;
• Fig. 2 shows a second view in lateral elevation of the present machine in an operating phase;

• Fig. 3 shows a plan view of a stretch of railway line on which the present machine is working;
• Fig. 4 shows a view in lateral elevation and partially in section of a rotatable clamp of the present machine, suitable for gripping, lifting and inclining the sleepers of the railway line whose roadbed needs to be reconditioned;
• Fig. 5 shows a plan view and partially in section of a bogie for the rotatable clamp of Fig. 4 to run on;
• Fig. 6 shows a front view, partially in section, of a unit for demolishing the roadbed, provided with a series of pneumatic hammers; and
• Fig. 7 shows a front view and partially in section of a variant embodiment of the demolition unit of Fig. 6.

With reference to these attached drawings and with particular reference to Fig. 1 thereof, no. 1 indicates an equipped wagon of the present machine for reconditioning railway roadbeds. The wagon 1 comprises at the top a longitudinal beam 2, whose front and rear ends 3 and 4, are supported by corresponding railway axles 5 and 6, or bogies, suitable for running on a track 7 of any railway line. This track 7 consists of a pair of rails 8, of which one is visible in the drawing, joined by a series of sleepers 9 suitably positioned and connected to the rails 8 by suitable removable fixing means 58. The track 7 rests on a roadbed 10 formed of ballast and/or other suitable material. The equipped wagon 1 comprises at its front and rear ends 3 and 4 control cabins 11 and 12. Starting from the front end 3 of wagon 1, the present machine comprises a gripping and lifting device 13 for the rails 8 of the track 7. This device 13 for each of the rails 8 comprises for example a pair of lifting rollers or clamps 14 held solid by an arm 15 connected to actuating means 16 for raising and lowering it, for example linear actuators. The fixed part of these actuating means 16 is connected to the longitudinal beam 2 of wagon 1. To the longitudinal beam 2 is also connected, immediately upline of this lifting device 13 for the rails 8, a unit for demolishing the roadbed, which comprises a row of pneumatic hammers 17 arranged transversely with respect to the track 7. Upline of these pneumatic hammers 17 a rotatable clamp 18 is shown, suitable for gripping an individual sleeper 9, lifting it, inclining it suitably and taking it back to a new position, as we will see more clearly below in the description of the operation of the present machine. This rotatable clamp 18 is connected to an actuator 19 connected at the top to a bogie 20 suitable for running longitudinally inside a box-section support 21 fixed to the longitudinal beam 2 of the wagon 1. On the longitudinal beam 2 a motor unit 22 is installed which activates a device 23 for excavating and collecting the material of the roadbed 10, which is known per se. This device 23 is suitably inclined and comprises an excavating chain, not illustrated, suitable for conveying the material of the roadbed onto a conveyor belt located inside the side-walls of the device. This belt conveys the material removed from the roadbed towards a further conveyor belt 47 which will transfer it to a following wagon, not illustrated, provided with screening means for the excavated material, to eliminate reject material and redistribute the cleaned material recovered by screening. The excavating device 23 is supported on the beam 2 by means of an oscillation pin 24 and by actuating means 25 which allow the inclination to be varied. All the devices described above and provided for on the wagon 1 are illustrated in Fig. 1 in a non-operating position.

Fig. 4 illustrates the rotatable clamp 18 in detail. This clamp 18 comprises two arms 26 suitable for rotating around a common pin 27 so as to separate and come together to clamp one of the sleepers 9 of Fig. 1. These arms 26 are controlled by an actuator 28. The clamp 18 is connected to a head 29 integral with the movable rod 30 of the actuator 19. This rod 30 runs inside a cylinder 31, forming an annular upper part 32 which rests, by means of a thrust bearing 33, on a support 34 fixed at the bottom to the bogie 20. This cylinder 31 is capable of rotating around a vertical axis with respect to said support 34 and said bogie 20, and roller bearings 35 are provided for this purpose in said support 34. The cylinder 31 is rotated in one direction or the other, and transmits said rotary motion to the arms 26 of the clamp 18, by means of an actuator 36, provided in the bogie 20. This actuator 36 (see also Fig. 5 in the attached drawings) comprises a cylinder 37 connected at one end and by a rotation pin 38 to a wall of the bogie 20. In this cylinder 37 there runs in one direction or the other a rod 30 connected, at one end and by means of a rotation pin 39, to a lever connected to a head 41 of the cylinder projecting into the bogie 20. This bogie 20 comprises a series of pairs of wheels 42 by means of which it can run along guides 43 formed in the box-section support 21 fixed to the longitudinal beam 2. At least one pair of such wheels, for example wheels 42', are connected to an activating reduction motor 44.

Fig. 6 illustrates the unit of the present machine for demolishing the roadbed 10. This demolition unit comprises two pneumatic hammers 17 positioned externally to the rails 8 of the track and two pneumatic hammers 17' positioned internally to the rails 8. Each of the pneumatic hammers 17 and 17' is controlled by its own lowering and raising actuator, respectively actuators 45 for the external pneumatic hammers 17 and actuators 45' for the internal pneumatic hammers 17'. Each of the actuators 45 for the external pneumatic hammers 17 comprises a cylinder 46 fixed, by means of suitable supports, to the longitudinal beam 2 of the wagon, and a movable rod 47 connected to the striking mass 48 of the relative pneumatic hammer 17.

Each of the actuators 45' for the internal pneumatic hammers 17' comprises a cylinder 46' fixed to a bogie 49 running transversely with respect to the longitudinal direction of advancement of the wagon, which is direction S in Fig. 2, and to the longitudinal direction of extension of the rails 8. This bogie 49, which can be similar for example to the bogie for the rotatable clamp described above, is supported by suitable guides 50 integral with the longitudinal beam 2 of the wagon. By means of this transversely movable bogie 49 the internal pneumatic hammers 17' can effectively demolish the stretch of roadbed 10 comprised between the two rails 8. Inside each of the cylinders 46' of each of the actuators 45' runs a rod 47' connected at the bottom to a beam 51 which holds solid the two striking masses 48' of the two internal pneumatic hammers 17'. These pneumatic hammers 17' therefore operate simultaneously and are provided with a central vertical guide made up of a rod 53 connected to the bogie 49 and a cylinder 54 connected to the beam 51. Naturally the number of internal and/or external pneumatic hammers provided in the demolition unit of the present machine could be different from what is illustrated in Fig. 6. It should be noted furthermore that the rails 8 are located in a stretch 55 of railway line with extremely small lateral spaces, for example in proximity to a station platform or in a tunnel.

Fig. 7 illustrates a variant of the demolition unit of the present machine. The external pneumatic hammers 17 are identical and operate in the same way with respect to what was previously illustrated in Fig. 6. The internal pneumatic hammers 17' however have the relative striking masses connected to each other by an actuator 52 and each of them is connected at the top to the beam 51 by means of an oscillation pin 57. The cylinders 46' of the two actuators 45' are connected directly to the longitudinal beam 2 of the wagon. To sum up, in this variant the two internal pneumatic hammers 17' manage to operate on the entire width of the roadbed 10 comprised between the rails 8 as a result of their variable inclination, controlled by actuator 52, and of their being fixed with oscillation pins 57 to beam 51.

We see below the operation of the present machine. During the operations which will be described below, the equipped wagon 1 moves in the direction S of advancement indicated in Fig. 2. When it becomes necessary to recondition a stretch of roadbed, it is first necessary to release the rails 8 from the sleepers 9 by manual removal of the means 58 fixing one to the other: see Figures 2 and 3 in the attached drawings, in which the fixing means 58 have been removed from the sleepers 9' and 9" located in front of the excavating device 23. In Fig. 3, note in particular the side-walls 59 of the device 23 for excavating and collecting the roadbed material, which advantageously have an overall side-to-side dimension which does not exceed the width of the sleepers 9, 9' and 9". This drawing also schematically illustrates the rotatable clamp 18, the group of pneumatic hammers 17 arranged parallel to the sleepers, according to any of the two forms of embodiment shown in Figs. 6 or 7, and the device 13 for gripping and lifting the rails. The actuators 16 of the device 13 are lowered in such a way that the means 14 of gripping the rails 8 are clamping the latter. These actuators are then retracted upwards so that the rails are temporarily raised from the released sleepers 9' and 9". The sleeper 9", situated at a given moment in the reconditioning process immediately in front of excavating device 23, is grasped by the arms 26 of the rotatable clamp 18, lifted from the roadbed 10 and inclined in a suitable manner so that it can be translated backwards past excavating device 23. Having arrived at its new laying position, in which the bogie 20 of the clamp 18 has travelled backwards substantially over the entire distance permitted by the support 21, the sleeper 9" is counter-inclined so as to make it assume once more the position transverse to the rails 8, and laid in the new position. Simultaneously, in the empty space left by the sleeper 9" for the work of excavating device 23, pneumatic hammers 17 and 17', sliding vertically upwards or downwards, penetrate the roadbed for the depth of lowering required. These pneumatic hammers 17 also break up any rock present in the roadbed and this broken-up rock is collected by excavating device 23 along with the ballast from the roadbed. The part of roadbed 10' situated upline of excavating device 23 (again, see Fig. 2) is lowered by the height required and reconditioned, and therefore the sleepers 9 in that part can be refixed to the rails 8. As mentioned above, all the material collected by the excavating device 23 will be transferred by the conveyor belt 47 to screening means provided on a wagon following wagon 1 where the present reconditioning machine is positioned.