The invention concerns an elastic pad designed to be placed between a sleeper and a rail of a railway, such that the rail rests on the sleeper via the elastic pad. The pad hereby has at least two supporting surfaces which are designed to abut against a rail foot of the rail on the one hand, and to the sleeper on the other hand.

Such elastic pads are used in railways for different reasons. One of the main reasons is that, as a result, the rail is acoustically isolated from the substrate and vibrations, caused by a railway vehicle moving along the rail, are damped. Furthermore, also wear by contact between the rail and the sleeper is prevented, and the rail is electrically isolated from the sleeper. The elastic pad also provides for a better and fatigue-resistant fastening of the rail to the sleeper and a better load distribution of the forces introduced by the passage of the railway vehicle to the sleeper and further foundation elements of the rail infrastructure.

In these elastic pads, we notice an accelerated aging and degradation of the elastomer. This degradation is mainly caused by heat generated as a result of (i) strain energy during the passage of the railway vehicle, (H) electrical voltage differences and (Hi) friction caused by the thermal expansion of the rails, which cannot or is difficult to be removed. This is in particular the case for elastic pads with a high stiffness which are used for example for railways designed for railway vehicles with high axle loads. The elastic pad hereby has a middle zone which becomes brittle and which expands from the middle to the outer edges of the pad. Due to this accelerated degradation the elastic pads will have to be replaced prematurely.

The elastic pads, in particular flat, relatively stiff elastic pads, are also disadvantageous in that they cling to the bottom side of the rail foot, which is inconvenient when the pads are to be replaced, and as a result of which the pads may possibly shift in relation to the sleeper, so that it is difficult to hold them centred over the sleeper. These elastic pads are nowadays made of elastomers such as for example cork rubber, polyurethane synthetic rubber, recycled rubber, natural rubber, recycled resin-bound rubber granules, polyurethane, thermoplastic elastomer (TPE), polyvinyl chloride (PVC) and/or ethylene vinyl acetate (EVA). Typically, the pads are made of recycled elastomers such as rubber derived from ground pneumatic tyres and which is thus obtained after an extensive recycling process. International patent applications WO2013/072345 A 1 describe in this context an interesting alternative method for recycling pneumatic tyres, such as car tyres, whereby a rubber strip can be obtained with a fabric layer embedded therein.

The invention aims to remedy the disadvantages listed above by presenting an elastic pad and a method making it possible to prevent the accelerated aging and degradation of the pad between the rail and the sleeper in a simple manner on the one hand, and to counter the clinging to the bottom side of the rail foot on the other hand. Furthermore, the invention also aims a sustainable ecological and economical alternative to such existing elastic pads. More specifically, the invention also aims to propose an elastic pad with a longer life.

To this aim, as mentioned in the appended claims, at least a part of the rubber layer of a pneumatic tyre is removed, which part forms an elastic pad, whereby this part is preferably removed together with at least a textile layer of the carcass of this pneumatic tyre, so that an elastic pad is obtained with on one side a textile layer forming a non-stick mat. This non-stick mat is hereby at least partly embedded in the elastic pad and exhibits at least partially free textile parts. These free textile parts are hereby intended to be placed against the bottom side of the rail foot.

Practically, the part of the rubber layer forming the elastic pad and the part of the textile layer are removed together from said pneumatic tyre, such that the textile parts of the textile layer extend above the elastic pad.

Consequently, an upper side of the pad is preferably provided with a textile structure and/or a woven structure designed to connect to the bottom side of the rail foot. Further, a bottom side of the pad is preferably provided with at least one groove, and the portion of the rubber layer forming the pad to this end contains at least a portion of a groove of the tread of the pneumatic tyre.

In an advantageous manner, a central opening is provided extending right through the pad from the top to the bottom of the pad. The groove preferably extends in the pad between the recess and at least one opening in an outer edge, so that in an operating condition in a railway, the air can circulate in the groove and the recess via the opening in the outer edge.

The invention also concerns a method for the construction of a railway with rails resting on sleepers, whereby such an elastic pad is provided in an attachment zone between the bottom side of the rail foot of the rails and the sleepers.

Other particularities and advantages of the invention will become clear from the following description of practical embodiments of the method and the device according to the invention; however, this description is given as an example only and does not limit the scope of the claimed protection in any way; the reference figures used hereafter refer to the accompanying drawings.

Figure 1 is a schematic representation of a cross section of a railway with elastic pads between the rails and the sleepers according to an embodiment of the invention.

Figure 2 is a schematic representation of a top view of an elastic pad according to a first embodiment of the invention.

Figure 3 is a schematic representation of a side elevation of an elastic pad according to figure 2.

Figure 4 is a schematic representation of a top view of an elastic pad according to a second embodiment of the invention.

Figure 5 is a schematic representation of a side elevation of an elastic pad according to figure 4.

Figure 6 is a schematic representation of a side elevation of an elastic pad according to a third embodiment of the invention. Figure 7 is a schematic representation of the construction of a rubber pneumatic tyre.

Figure 8 is a schematic representation of a detail of a sleeper, a rail and an elastic pad according to an embodiment of a method of the invention.

Figures 9, 10 and 11 are schematic representations of a top view of variants of an elastic pad according to the invention.

The invention generally concerns a recycled elastic pad for railways which is preferably made in one piece of a rubber layer of a pneumatic tyre, such as for example a car tyre. Thus, the pad preferably at least includes a portion of the rubber layer between the tread and the carcass of the pneumatic tyre.

To this end, at least a part of a rubber layer of a pneumatic tyre is removed, which part forms the elastic pad, whereby this part is preferably removed together with at least a textile layer of the carcass of this pneumatic tyre, such that an elastic pad is obtained with on one side a textile layer forming a non-stick mat. Thus, this non-stick mat is provided with textile parts which are at least partly embedded in the elastic pad. The textile parts hereby consist at least partially of cords which are substantially parallel to a supporting surface of the elastic pad.

The elastic pad is designed to be placed between the top side of a sleeper and the bottom side of the rail foot of a rail, at the level of the attachment of the rail to the sleeper. Such sleepers can be made for example of concrete, wood, plastic or metal or combinations thereof. Between the rail and the elastic pad and/or between the sleeper and the elastic pad, the sleeper and/or the rail may be further provided with additional elements such as for example a metal or plastic plate f on the height adjustment or attachment ofcthe rail.

According to the invention, the elastic pad is preferably provided with grooves extending over the support surface of the elastic pad. These grooves can serve as ventilation and/or drainage ducts. The grooves preferably consist at least partly of longitudinal grooves that are already present in the tread of the pneumatic tyre. Also a recess may be provided, extending between the top side and the bottom side of the pad, and which is preferably connected to the environment by the grooves when the pad is placed between the sleeper and the rail. This recess thus forms a free space in the pad which can be ventilated and/or drained by means of the grooves.

Figure 1 schematically represents a railway which is composed of sleepers 2 with rails 3 on them according to an embodiment of the invention. The rails 3 rest on elastic pads 1 which in turn rest on the sleepers 2 in a rail attachment zone 25. This rail attachment zone 25 is a zone of the sleeper 2 in which the rail 3 and the sleeper 2 overlap and in which the rail 3 rests on the sleeper 2. By means of fasteners 26 known as such, the rails 3 in this zone 25 are attached to the sleepers 2.

The bottom side 6 of the elastic pad 1 abuts almost entirely against the top side 15 of the sleeper 2, whereas the top side 5 of the elastic pad 1 abuts almost entirely to the bottom side 16 of the rail foot 17. Between the top side 5 and the bottom side 6 of the pad 1 is situated an outer edge 8 of the pad 1. After the pad 1 has been placed between the rail 3 and the sleeper 2, said outer edge 8 stays at least partly free.

In the railway according to the embodiment of the present invention, the fasteners 26 extend right next to the elastic pad 1. A portion of the outer edge 8 of the elastic pad 1, which runs practically parallel to the longitudinal direction of the rail 3, hereby connects to the fasteners 26. In contrast, a portion of the outer edge 8 of the elastic pad 1, which is substantially transverse to the longitudinal direction of the rail 3, remains freely accessible. This is also the portion of the outer edge 8 which runs practically parallel to the longitudinal direction of the sleeper 2.

The rail 3 may possibly be additionally provided with a rigid plate between the elastic pad 1 and said rail 3, and/or the sleeper 2 may possibly be additionally provided with a rigid plate between the elastic pad 1 and the sleeper 2, not represented in the figures. This is for example to protect the elastic pad 1. The rigid plate can be made of metal or plastic. Between the elastic pad 1 and the rail 3 may also be provided a film with studs, whereby the studs are preferably directed to the bottom side 17 of the rail foot 16 so as to prevent the elastic pad 1 from clinging to the bottom side 16 of the rail foot 17, not represented in the figures. This film is a non-stick mat which can be glued to the top side 5 of the elastic pad 1 and which possibly comprises a textile structure and/or a woven structure. The studs can hereby be mushroom-shaped for example, and preferably have a maximum height of 1 to 2 mm, preferably some 0.1 to 0.2 mm. According to the invention, this non-stick mat preferably consists of a textile layer which is partly derived from the carcass of a pneumatic tyre.

Figures 2 and 3 schematically represent a rectangular elastic pad 1 according to a first embodiment of the invention. The elastic pad 1 has two supporting surfaces 20. A first supporting surface 20 comprises a substantially flat rectangular top side 5, represented in figure 2. This top side 5 is designed to abut against the bottom side 16 of the rail foot 17. A second supporting surface 20 comprises a bottom side 6 of the elastic pad 1 and is also substantially flat and rectangular and is designed to abut against the sleeper 2. The width BK of the elastic pad 1 substantially corresponds to the width of the rail attachment zone 25 and/or the width of the rail foot 17 resting on the elastic pad 1. The length LK of the elastic pad 1 substantially corresponds to the length of the rail attachment zone 25, crosswise to the sleeper 2. Consequently, the dimensions of the pad 1 substantially correspond to the dimensions of the overlap between the rail 3 and the sleeper 2.

The pad 1 can be provided with flaps 9 designed to extend sideways, according to the longitudinal direction of the sleeper 2, past the rail fasteners 26. These flaps _s 9-are-preferably provided on either side of the _^ rail fasteners 26 and they make sure that the pad I is immobilized in the rail attachment zone 25 in relation to the rail fasteners 26 when the rail 3 is fixed with the pad 1 on the sleeper 2.

The height HK of the pad 1 corresponds to the height of the outer edge 8 of the pad and preferably amounts to some 5 to 8 mm. According to the invention, the pad 1 in this first embodiment is provided with a number of grooves 22 extending in the supporting surface 20 on the bottom side 6 of the pad 1. In figures 2 and 3, the pad 1 has three grooves 22. Additional grooves may possibly be provided.

According to this first embodiment, the grooves 22 are preferably practically parallel to the longitudinal direction of a rail 3 when this rail 3 rests on the elastic pad 1 in a railway in the operational condition. Hence, the grooves 22 are transverse to the sleeper 2.

The grooves 22 extend over the supporting surface 6 of the pad 1 as of an outer edge 8 up to an opposite outer edge 8'. A front view of an outer edge 8 according to this embodiment of the invention is represented in figure 3. At the height of this outer edge 8, the grooves 22 lead to the environment via an opening 18. This allows for an air flow through this groove 22, so that heat can be continuously removed for example. As a result, the grooves 22 also take care of the removal of moisture.

The grooves 22 may consist of longitudinal grooves which are already present in the tread of the pneumatic tyre or which can be additionally provided in the pad 1. Preferably, these grooves 22 are shaped such that the shape factor of the elastic pad remains practically unaltered by the provision of the grooves 22. Thus, the cross-section of these grooves 22 is preferably V- shaped. Thus, the pad 1 preferably has a stiffness which is sufficiently high, so that the groove 22 is not or at least not entirely compressed when a load is applied to the pad 1 as a railway vehicle moves over the rail 3.

A second embodiment of the invention, represented in figures 4 and 5, differs from the first embodiment in that a recess 4 is provided in the middle of the pad 1. This recess 4 makes sure that the bottom side 16 of the rail foot 17 remains free in the middle of the rail attachment zone 25.

According to this second preferred embodiment of the invention, the recess 4 is circular. The centre of this circular recess 4 preferably substantially corresponds to the intersection of the diagonals of the rectangular pad 1. According to this preferred embodiment, said recess 4 has a diameter DU which substantially amounts to 20 mm. Consequently, the pad 1 is ring-shaped with a circular inner edge 19 and a rectangular outer edge 8.

As the pad 1 has a recess 4 in the middle, the load of the rail 3 is more evenly distributed over the entire elastic pad 1.

Further, grooves 22 are provided as in the first embodiment of the invention. These grooves 22 extend between the recess 4 and the outer edges 8 of the pad 1. A front view of an outer edge 8 according to this preferred embodiment of the invention is represented in figure 6. At the height of this outer edge 8, the grooves 22 open into the environment via an opening 18. These grooves 22 hereby run substantially parallel to the rail 3 resting on the pad 1 when said rail 3 is attached to the sleeper 2. The grooves 22 are thus perpendicular to the sleeper 2.

Providing a central recess 4 with grooves 22 ensures a longer ₍ life of the elastic pad 1. In conventional elastic pads 1 with neither a central recess 4 nor grooves 22, the combination of moisture accumulation and the concentration of stray electric currents, together with the compression of the elastic pad 1, result in a degradation of the elastic material of the pad 1. This degradation starts in the middle of the pad 1 and extends towards the edges 8. As a result, the properties of this elastic pad 1 are so badly damaged that it will have to be replaced prematurely.

The recess 4 in the elastic pad 1 according to the invention forms a hollow space in the middle of the rail attachment zone 25. The combination of this hollow space with the grooves 22 between this space and the outer edge 8 of the pad 1 provide for a ventilation and drainage of the attachment zone 25. As a result, accumulation of moisture is prevented. The recess 4 also allows for the discharge of stray electric currents to the undersoil. The combination of the recess 4 and the grooves 22 further provide for a cooling of the attachment zone 25 when for example a warm-up occurs due to stray electric currents and/or by increased compression or friction when railway vehicles move over the railway.

The recess 4 also functions as an air bellows. The recess 4 hereby forms bellows which are partially compressed when the rail 3 resting on the latter is loaded. Thus, air is sent to the environment via the grooves 22. When the rail 3 is relieved again, the pad 1 will expand once more and air is drawn in from the environment. When the rail 3 is loaded, the grooves 22 are preferably not fully compressed.

5 A third embodiment of the invention differs from the first and second embodiments in that the supporting surface 20 forming the top side 5 of the pad 1 is provided with a non-stick mat, as represented in figure 6. This nonstick mat consists of a textile layer which is at least partially embedded in the pad 1. This layer 14 is designed to connect to the bottom side 16 of the rail foot

10 17 and it prevents the pad 1 from clinging to said bottom side 16 of the rail foot 17. As a result, it is easier to replace a pad 1. This problem mainly arises with flat and relatively stiff pads which have the property to cling to the rail foot.

A fourth embodiment of the invention, not represented in the figures, differs from the preceding embodiments in that there are no grooves in

15 the supporting surfaces of the pad.

A fifth embodiment of the invention, not represented in the figures, differs from the above-described embodiments in that additional grooves 22 are provided on the top side 5 and/or the bottom side 6 of the pad 1. These grooves 22 are cut or carved and may for example be transverse to the existing

20 grooves 22 on the bottom side 6 of the pad 1.

The invention also concerns a method for manufacturing one of the above-described pads 1 from a pneumatic tyre. In particular, the invention also concerns a method for manufacturing an elastic pad 1 with a non-stick mat derived from a pneumatic tyre.

25 Thus, according to the invention, the elastic pad 1 is obtained from a pneumatic tyre, i.e.. a car tyre or the like. Thus, material from a worn car tyre can be re-used at least in part for this purpose. Said car tyre may consist for example of a radial tyre or a diagonal tyre and mainly includes an elastic material such as synthetic rubber.

30 In general, a pneumatic tyre is built as represented in figure 7.

The outside 10 has a rubber tread 7 with possibly a relief. This tread 7 is the top side of a rubber top layer 13. The relief exhibits one or several longitudinal grooves 22 extending around the pneumatic tyre according to the circumference of the tyre or also according to the longitudinal direction of the tread 7. Further, said relief may possibly exhibit even smaller profile grooves 21 which are substantially transverse to said longitudinal grooves 22.

Under said rubber top layer 13 is situated what is called a carcass 24 with a rubber under layer 12. The carcass 24 consists of one or several textile layers 14. Even more layers and/or an additional reinforcement of steel may possibly be provided as well. The inside 11 of such a tyre is usually provided with a rubber airtight layer.

According to a method of the invention, the rubber top layer 13 and at least one textile layer 14 situated against it are removed together from the tyre according to the circumferential direction of the tyre. To this end, the outermost part of the tyre is cut off, preferably substantially parallel to the tread 7 and the textile layer 14, just under the textile layer 14. Thus is obtained a strip comprising at least a part of a textile layer 14 of the carcass 24 and a part of the rubber layer 13. In this case, the strip has a width corresponding for example approximately to the width of the tread 7. Said width can for example substantially amount to 180 mm and it depends on the dimensions of the recycled car tyre.

It is also possible to obtain said strip by using a plane or a rasp to remove material from the inside of the pneumatic tyre. Optionally, also material from the outside of the pneumatic tyre can be removed in this way.

Consequently, according to the invention, at least a part of the thickness D of the carcass 24 with the textile layer 14 is removed from the pneumatic tyre together with at least a part of the thickness E of a rubber layer 13 situated against it.

The total thickness C of the strip also depends on the nature of the car tyre and the wear of its tread 7. Said thickness C may amount for example to some 5 mm to 15 mm. Preferably, the thickness amounts to some 6 mm to 10 mm, in particular some 8 mm, or specifically some 6 mm to 7 mm.

Depending on the tyre and also the condition of the tyre, longitudinal grooves 22 are present or absent. If desired, different strips can be joined together. Thus, these strips can be placed next to each other and stiffened by means of what is called a 'temperature/pressure/time' process (TPT) in a press oven. The strips are hereby fixed to each other by subjecting the elastomeric rubber to an elevated temperature and pressure for a certain period of time. Thus can be obtained a strip which is wider than the tread 7 of a pneumatic tyre.

The required shape and size of the elastic pad 1 is cut, sawn or punched from this strip. Thus is obtained an elastic pad 1 with dimensions that are suitable to place the pad 1 between the rail 3 and the sleeper 2 at the height of the fasteners 26.

The textile layer 14 comprises textile threads and/or cords 27 which, for example in a radial tyre, run mainly parallel to the surface of the tyre and transversely to the direction of travel. The direction of travel is hereby the direction in which the tyre is moving when it rolls over the tread 7. These textile threads and/or cords 27 may also be parallel to the direction of travel or they may be inclined in relation to the direction of travel. The textile threads and/or cords 27 can be made of for example synthetic fibres such as rayon, polyester, polyamide and/or aramid. The textile layer 14 may also include steel wires. Consequently, depending on the application of the elastic pad, a certain type of car tyre can be chosen for recycling.

As a result, the textile layer 14 consists of a structure with textile parts such as textile threads and/or cords 27. Thus, the textile layer 14 may consist of a woven structure, parallel cords 27 and/or intersecting cords 27. Thus, this structure may consist of parallel cords 27 which abut against each other and possibly are woven into each other. Said structure has a certain thickness which amounts to for example 1 mm to 3 mm, preferably nearly 2 mm. These textile threads and/or cords 27 are at least partly embedded in the rubber top layer 13. Further, in an advantageous embodiment, these textile threads and/or cords 27 are at least partly free on a side opposite to the rubber top layer 13. When the textile layer 14 is already at least partly embedded in the rubber layer 13, usually no additional provisions need to be made to fix the textile layer 14 to the elastic pad 1.

The textile parts 27 preferably extend above the elastic pad 1 up to a height which amounts to 0.1 to 3 mm, in particular 0.2 to 2 mm, and preferably 0.2 to 1 mm.

The textile layer 14 may be processed in such a manner that textile parts 27 are free and at least partly not surrounded by rubber. This can be obtained by processing the textile layer 14 for example by means of a comb, a plane or a grinding element such as abrasive paper, a scouring pad, a sanding block.

Incisions can possibly be made in the rubber top layer 13 and/or the textile layer 14 to thus make the elastic pad 1 with the textile layer 14 more flexible and flatter. These incisions can for example be made longitudinally and/or diagonally in relation to the direction of travel of the tyre.

In this method according to the invention, also a central recess 4 is preferably provided whereby at least one groove 22 crosses the recess 4 for ventilation and drainage thereof. For this purpose, a recess is made right through the pad 1 through at least one longitudinal groove 22 of the pneumatic tyre.

Finally, the invention also concerns a method for producing a railway whereby an elastic pad 1 as described above is provided between the rail foot and the sleeper. According to a preferred embodiment of this method, the groove 22 connects the recess 4 to the environment when the elastic pad 1 is placed between the sleeper and the rail. To this end, the groove 22 has an opening 18 between the rail foot 13 and the sleeper 2, as represented in figure 8.

Naturally, the invention, is not restricted to the above-described method and device according to the invention. Thus, depending on the desired application, the size and height of the pad 1 may vary. The pad 1 can thus also be made without the flaps 9. Thus, the elastic pad 1, according to the invention, may take a variety of forms which fall within the scope of the invention, as is represented for example in figures 9, 10 and 11. Thus, for example, the recess in the centre of the pad may also assume a rectangular shape. The various characteristics of the above-described embodiments may of course also mutually combined.