KR20230047074A - railway sleeper - Google Patents

Abstract

As a railway sleeper for fixing at least one pair of rails (2, 2') of a railway network, the railway sleeper (1) has a contact surface (3) on which each of the pair of rails (2, 2') is spaced apart from each other and fixed A railway sleeper comprising a hollow sector (4) delimited by the association of the contact surface (3) with the fixed wall (5, 5'), opposite the contact surface (3) and the fixed wall A railway sleeper is disclosed, characterized in that a free portion 7 adjacent to (5, 5') is formed, and the railway sleeper (1, 1') is made of a composition having a bending modulus of 5000 MPa or more.

Description

railway sleeper

The present invention relates to a railway sleeper and a method for manufacturing the sleeper. More specifically, the present invention relates to a sleeper with a hollow sector and a manufacturing method thereof.

Railway sleepers are one of the various components of the railway network and, together with ballast and other fixing elements, promote the correct anchoring (fixation) of the rails on which the carriages move.

Most (about 90%) of the elements disclosed in the prior art are made of wood, the rest being steel, concrete or recycled plastic sleepers.

Wood sleepers have an estimated useful life of several decades and should be replaced after this period. More than 3 million wooden sleepers are replaced each year, and legal restrictions relating to the use of a determined type of this raw material are forcing the sector to seek alternatives to these elements.

Alternatives have focused on the use of sleepers made of wood, steel, concrete, reforested-timber and plastic (recycled or new).

The sleepers made of virgin plastic showed good behavior. On the other hand, the use of sleepers of this type is limited to narrow-gauge passenger-carrying railways with efforts other than those by freight systems. Recycled plastic sleepers, used in some rail networks, present serious structural problems with chronic propagation of cracks, warping and anchoring problems.

Basically, in the case of recycled sleepers, it becomes difficult to obtain homogeneity of the materials that make up the sleepers. Therefore, structural problems are detected and accidents (derailments) occur, making this type of sleeper virtually unusable.

Concrete sleepers, despite their widespread prevalence in railway networks worldwide, are considered to be suitable for the properties of railway plates and ballasts of lines present in some countries (e.g. Brazil) due to the considerable inertia and stiffness of the most commonly available commercial models. Not proven.

This tends to cause high breakage of the ballast, which not only makes accidents possible, but also increases railway maintenance costs.

Classified according to shape, concrete sleepers can be of a single block type formed from one strong, continuous piece, which is exposed to large bending moments in different parts of the sleeper.

There are also concrete sleepers of the twin-block type (mixed sleeper) consisting of two solid reinforced concrete blocks placed under each rail and connected by a flexible steel bar.

Thanks to the elasticity of the beam, the two blocks of concrete will be immune to most stresses of static bending and cross bending, which sleepers made of prestressed concrete hardly withstand.

Among concrete sleepers, there are also polyblock sleepers in which two reinforced-concrete blocks are arranged at either end with an intermediate piece also made of concrete. The blocks of the sides and the middle block are connected by bar steel means with a high elastic limit, and are stressed and fixed at the ends.

Several advantages can be mentioned regarding the use of concrete sleepers compared to wooden sleepers. For example, concrete sleepers have a durability of about 50 years and, thanks to their large mass and elastic fixation, exhibit stiffness in the lateral and vertical directions.

In addition, concrete sleepers have the effect of extending the life and reducing the bending stress (on the rail) as well as easy and quick replacement of the rail due to the stability of the railroad.

In addition, the use of concrete sleepers reduces the frequency of derailments, which in turn improves ride quality and significantly reduces permanent maintenance costs.

On the other hand, the use of concrete sleepers presents several disadvantages, such as higher transport costs due to the greater weight of these sleepers compared to wooden sleepers, as well as the problematic re-use of sleepers after a derailment has occurred.

Also, the use of concrete sleepers makes it impossible to adjust the fastening system to rail wear and rail expansion. In addition, expensive equipment is required for railway installation and maintenance, and in some cases, ballast may be damaged due to the heavy weight of sleepers.

As already mentioned, besides concrete and plastic sleepers, the prior art further discloses sleepers made of steel. Steel sleepers exhibit satisfactory behavior in use. On the other hand, the weight of a steel sleeper depends directly on the highly volatile steel price, so the cost can be high and uncertain.

The anchoring of this type of sleeper is usually done with screws and chestnuts and requires permanent maintenance. In addition, fixation by means of screws results in weakening of the sleeper due to the bore formed in the sleeper.

The advantages of this type of sleeper include recyclability due to the materials used, long service life (about 60 years), inertness and non-toxicity, low installation cost, simple transportation and non-combustibility.

As a disadvantage, the use of steel sleepers requires a larger number of interventions and changes in the tamping area. Additionally, sleepers of this type may entail travel disruptions due to isolation risks and may still suffer from corrosion problems.

As for wooden sleepers, they must be treated (chemically) beforehand to make them suitable for use. Obviously, such chemical treatments are harmful to the environment.

The chemical treatment station serves to store the sleepers and apply preservatives to prolong the useful life of the sleepers and prevent the growth of fungi and insects.

In addition to being a lengthy process involving many steps, the sleeper treatment process can cause various environmental problems such as air pollution due to breakage of storage tanks, treatment cylinders and tubes containing preservatives.

It is also not uncommon for employees to absorb, inhale and ingest chemicals. In addition, the use of herbicides and pesticides can contaminate soils and streams, causing changes in the behavior of fauna and causing species to become extinct.

It is also possible to make sleepers from reforested wood, and this type of sleeper exhibits considerably less resistance than hardwood.

Also, since sleepers cannot be treated with some products that are very harmful to the environment (e.g. creosote), they become attached to biological agents such as bacteria and termites, resulting in a very short lifespan (on the order of 3-4 years). This is much shorter than the useful life of sleepers made of hardwood.

The present invention aims to overcome the problems existing in the use of the above-mentioned sleepers by their structural construction and manufacturing process.

The proposed sleeper has no restrictions on its use and is suitable for use on railway tracks in both construction and operation to transport freight and/or passengers.

The plastic sleepers known from the prior art (either new or recycled) do not exhibit an optimized combination between the weight of the piece and the elastic modulus.

The most well-known plastic proposal precisely mimics the shape of a wooden sleeper, making the piece heavier and consuming more raw materials, as well as manpower and machinery to make the piece. These factors slow down the production process and increase the final price of sleepers.

The present invention proposes a railway sleeper, preferably but not limited to, made by a high-productivity process, preferably by extrusion, preferably made of polypropylene with glass fibers, and additionally having a stiffness comparable to that of hardwood sleepers. It has a structural shape that can achieve, and is competitive in terms of cost.

In addition, the sleeper proposed in the present invention has a lower final price, so it is easy to transport and install the piece, a standard fixing device used for wooden sleepers can be used, and a standard machine used for installation and maintenance of sleepers is used, The material of manufacture allows the product to be recycled at the end of the sleeper's useful life.

Structurally, the proposed railway sleeper includes a hollow sector (penetrating sector) which acts as an important difference for the ballast fastening function and properties. Due to the proposed shape, the ballast used in the railroad becomes an integral body by penetrating the sleeper.

Due to compaction of the ballast inside the sleeper, greater stiffness will be created for the ballast/sleeper system, and the final moment of inertia will be the sum of the moments of inertia of the sleeper and the ballast layer disposed therein.

In addition, due to the shape of the proposed railway sleeper, it is easy to install and maintain as a light sleeper (in the range of 40 to 45 kg), easy to transport by two people, and fastened as one piece (with one sleeper) to transport By being suitable for the following, it brings countless logistical advantages.

The present invention aims to develop a high-performance railway sleeper for use on railway tracks under construction or in operation, used for transporting freight and/or passengers.

Another object of the present invention is to provide a sleeper in which installation and production processes are simplified to reduce working time, meet market demands, and ensure efficiency in the use cycle of the sleeper.

The present invention also solves problems of current solutions (described in the prior art) such as high stiffness and weight of concrete which damage the ballast layer, useful life of poor quality wood, electrical conductivity of steel and reliability problems of solutions using recycled resins. It aims to overcome (mostly) the main problems.

Further, the present invention aims to provide a railway sleeper of sustainable attractiveness, which preferably uses polypropylene as a raw material and can be recycled at the end of its useful life.

It is a further object of the present invention to provide a railway sleeper with a hollow sector so that the ballast of the railway network penetrates the sleeper to enhance the rigidity of the ballast/sleeper system.

Further, one of the objects of the present invention is to provide a structural configuration of sleepers having an inverted-U shape.

A further object of the present invention is to provide a railway sleeper made from a first material and made from a composition comprising said first material.

Another object of the present invention is to provide a railway sleeper in which the inner and outer walls are made of a first material and the layer arranged between these walls is made of a composition comprising the first material. The inner wall (or inner layer) may optionally not be included.

Similarly, the outer wall (or outer layer) may optionally be absent.

Accordingly, it is contemplated that embodiments comprising an inner wall and an intermediate layer (described below), an outer wall and an intermediate layer, and an intermediate layer without an inner wall and an outer wall will be effective for the purposes of the present invention.

The present invention also aims to provide a railway sleeper produced by an extrusion/coextrusion process.

Another object of the present invention is to provide a sleeper having a hollow sector comprising a support groove.

A further object of the present invention is to provide a method for producing railway sleepers by means of an extrusion process which makes it possible to compress the composition used to make the sleepers in the straightener of the extruder and uniform cooling throughout the thickness of the sleepers produced. is to do

Finally, the present invention aims to satisfy the Brazilian market on a large scale with good quality and reliability.

An object of the present invention is a high-performance railway sleeper made of polypropylene with a high glass fiber content, which can preferably range from 5 to 40%, preferably by an extrusion process in which pure polypropylene is applied as an outer sheath in a co-extrusion process. is achieved by

The proposed sleeper exhibits a high elasticity module and performance comparable to that of wood, so it can be applied to railroads transporting cargo and passengers. The sleeper proposed in the present invention has the following main advantages.

- Availability and reliability of raw materials to meet large markets;

- good electrical insulator;

- High elasticity module;

- fully recyclable;

- the same installation and maintenance as for wooden sleepers, using the same tools and equipment;

- Improved ease of transportation and maintenance, reduced logistics costs;

- inert and impermeable;

- Can be used with wooden sleepers;

- availability of fastening systems currently used for wooden sleepers;

- Various lengths and shapes of sleepers can be produced to meet various gauges and AMV (Line Shift Device).

The present invention will be described in more detail below with reference to examples of embodiments shown in the drawings.
1 is a plan view of a railway network suitable for accommodating sleepers proposed in the present invention, FIG. 1(a) shows a simple railway network, and FIG. 1(b) shows a multi-rail railway network.
Figure 2 shows a cross-section of the proposed embodiment as a railway sleeper.
Figure 3 is a further representation of a cross section of a proposed embodiment for a railway sleeper, showing preferred dimensions.
Figure 4 shows a cross-section of a further proposed embodiment for a railway sleeper.
5 is a sectional view of a further proposed embodiment for a railway sleeper.
Fig. 6 is a cross-sectional representation of a proposed structural embodiment for the railway sleeper shown in Fig. 5, showing a preferred configuration.
7 is a view showing a cross section of a further embodiment of the sleeper proposed in the present invention.
Fig. 8 further shows a cross-section of the railway sleeper shown in Fig. 7, illustrating a preferred one.
9 is a view showing an embodiment including a support groove as an additional embodiment proposed for the sleeper proposed in the present invention.
10 is a view showing an embodiment including a plurality of support grooves as an additional embodiment proposed for the sleeper proposed in the present invention.
Figure 11 shows a further proposed embodiment for the sleeper proposed in the present invention, this embodiment comprising a plurality of fixed teeth.
Fig. 12 shows a further embodiment proposed for the railway sleeper of the present invention, which comprises a contact surface protruding beyond the fixing wall, further discloses a double support point, and Fig. 12(a) adds a support groove. FIG. 12(b) discloses a double support point, FIG. 12(c) discloses a plurality of support grooves, and FIG. 12(d) discloses a plurality of fixed teeth.
Figure 13 shows a further embodiment proposed for the sleeper of the invention, which illustrates an embodiment further comprising a double support point in which the contact surface does not protrude beyond the fixed wall but into the hollow sector, and Figure 13 ( a) further discloses a support groove, FIG. 13(b) discloses a double support point projecting into the hollow sector, FIG. 13(c) discloses a plurality of support grooves, and FIG. 13(d) discloses a plurality of support grooves. Initiate fixed teeth.
Fig. 14 is a cross-sectional representation of a proposed structural embodiment for the sleeper shown in Fig. 13(c), highlighting the preferred dimensions.
Figure 15 is a further representation of a cross section of a proposed structural embodiment for a railway.
Figure 16 is a cross-sectional representation of a proposed structural embodiment for a railway sleeper, with inner and outer walls and interlayers highlighted.
17 shows a cross section of an additional embodiment of the sleeper proposed in the present invention, which further includes the support surface shown in FIG. 17(a), and FIG. 17(b) adds a plurality of support grooves. Fig. 17(c) further illustrates a plurality of stationary teeth and protrusions of the support and contact surface beyond the stationary wall, and Fig. 17(d) illustrates a plurality of stationary teeth.
18 is a profile representation of a railroad network including sleepers proposed in the present invention, further illustrating a fixed block.
19 shows the fastening of a railway sleeper to a fastening block and additionally the use of transversely arranged fastening elements on the sleeper.
20 shows possible structural embodiments for a fixed block used with sleepers proposed in the present invention.
21 shows a further embodiment of a fixed block used in combination with sleepers proposed in the present invention.
22 shows the fixing of the sleeper proposed in the present invention by means of a metal plate, and FIG. 21(a) shows the use of a smaller metal plate compared to the metal plate shown in FIG. 21(b).
Fig. 23 illustrates the fixing of the railway sleeper shown in Fig. 19 by metal plates, where Figs. 23(a) and 23(b) illustrate divided plates.
24 shows an embodiment in which the sleeper is made only of an intermediate layer.
Figure 25 shows an embodiment where the railway sleeper includes an intermediate layer and an inner layer.
Figure 26 shows an embodiment where the railway sleeper includes a middle layer and an outer layer.
27 is a further representation of the sleeper proposed in this application.

The present invention relates to a railway sleeper (1) (also referred to as a sleeper (1)).

Structurally and referring to FIGS. 1 to 27, the sleeper 1 proposed in the present invention includes a hollow sector 4, so that the ballast used in the railway network penetrates into the sleeper 1 and compacts it, so that the sleeper / Increase the rigidity of the ballast assembly.

1 to 27 show preferred structural embodiments proposed for railway sleepers 1, all of which retain the properties referring to the shape of the hollow sector 4 as well as the material used (composite). The characteristics of each embodiment are discussed below.

Referring to Fig. 1, the proposed sleeper 1 is used to fix at least one pair of rails 2, 2' of a railway. The sleeper 1 is suitable for use in a simple railway network provided with only a pair of rails 2 and 2', as shown in FIG. 1 (a), or, as shown in FIG. 1 (b), It should be mentioned that it can still be used at points in the rail network.

1 also refers to the contact surface 3 of the proposed sleeper 1 . The contact surface 3 preferably consists of a plane for the arrangement of each rail 2, 2' of the railway network.

FIG. 2 shows a cross section of a first structural embodiment of the railway sleeper shown in FIG. 1 . It can be seen that the fixing walls 5 , 5 ′ protrude from the contact surface 3 , preferably plane, delimiting the aforementioned hollow sector 4 .

More specifically and with reference to FIG. 2 , the hollow sector 4 is delimited from the contact surface 3 and by the fixing walls 5 , 5 ′. Thus, the free part adjacent to the fixing wall 5, 5' is set opposite the contact surface 3. That is, the proposed embodiment for the sleeper 1 forms an inverted-U shape.

Accordingly, the free part 17 is to be understood as the (face) perforated (open) part of the hollow sector 4 , in which the ballast of the railway network passes through the railway sleepers 1 and more specifically the hollow sector 4 to be able to penetrate The lower part of the fixed wall (5, 5'), that is, the part supporting the sleeper (1) on the ground is called a support point (7, 7'), and these support points (7, 7') are connected to the contact surface (3) and the fixed wall ( 5, 5') is opposite to the linkage point.

Referring to Figures 3 and 4, the fixing walls 5, 5' define the first width L1 of the proposed sleeper 1. As shown in FIG. 3, considering the preferred thickness E for the sleeper 1, the first width L1 is the outermost part (outer wall) of the fixed walls 5 and 5', that is, the hollow sector ( The range is determined by the part not adjacent to 4).

Regarding the support points, they can assume different structural embodiments for the proposed sleeper 1 as shown in FIGS. 2 to 4 .

The embodiment shown in Figs. 2 and 3 is referred to as a simple support point 7, 7', where the contact thickness of the sleeper 1 with the ground consists of the thickness E of the sleeper 1 itself.

On the other hand, the embodiment shown in FIG. 4 and more specifically FIG. 4 (a) provides dual support points (8, 8'), and the contact thickness of the sleeper (1) and the ground is the thickness (E) of the sleeper (1) represents a larger dimension.

More specifically, the distance between the support points 7 and 7' shown in Fig. 3 and the support points 8 and 8' shown in Fig. 4 (Fig. 4(b)) defines the second width L2 of the sleeper. . Thus, in embodiments where simple support points 7 and 7' are used, the first width L1 has the same dimensions as the second width L2 as shown in FIG. 3 .

On the other hand, in an embodiment in which double support points 8 and 8' are used, the first width L1 is smaller than the second width L2 as shown in FIG. 4, more specifically FIG. 4(b).

5 shows a third embodiment effective for the proposed sleeper 1 . In this embodiment, we observe elements previously discussed in previous embodiments, such as the contact surface 3 and the fixing walls 5, 5'.

The proposal shown in FIG. 5 sets the same dimensions for the first and second widths L ₁ and L ₂ , respectively, using simple support points 7 and 7 ′ (as shown in FIG. 6 ).

In order to enhance the bearing capacity of the sleeper 1 proposed in the present invention, the embodiment shown in FIGS. 5 and 6 has a groove 9 protruding from the contact surface 3 toward the hollow sector 4 of the railway sleeper 1. ) is also available.

Figure 7 shows a further structural embodiment for the proposed sleeper 2, which uses a support groove 9 and double support points 8, 8'.

The support groove 9 can protrude through the entire height of the hollow sector 4 as shown in the embodiment shown in FIGS. 6 and 7 , or alternatively, as shown in FIG. 9 , the support base ( 3) can protrude freely towards the hollow sector 4.

In a further structural configuration, the support groove 9 projects further from at least one of the fastening walls 5, 5' towards the hollow sector 4 of the sleeper 1.

This embodiment is shown in FIG. 10 , where it can be observed that the proposal includes a support groove 9 projecting from the contact surface 3 and a support groove projecting from the fixing walls 5 , 5 ′.

An alternative structural embodiment for the railway sleeper comprises a support groove 9 protruding only from the fastening walls 5, 5' or only protruding from one of the fastening walls 5, 5'. Also, the number of support grooves 9 shown in the drawings should not be regarded as a limiting feature of the present invention.

The proposed sleeper 1 further comprises a plurality of fixing teeth 12, which are preferably arranged on at least one of the fixing walls 5, 5'.

More specifically, the fixing teeth 12 are arranged in portions of the fixing walls 5, 5' that are not adjacent to the hollow sector 4, or, still for better understanding, the fixing teeth 12 are arranged on the fixing wall 5 , 5') are arranged on the outer wall.

As can be seen in Fig. 11, the fixing tooth 12 is preferably configured as a recess (channel) running the entire length of the sleeper.

The fixed teeth 12 do not interfere with the mechanical properties of the sleeper 1 . More specifically, these teeth 12 provide a stronger anchoring of the sleeper 1 to the ballast, allowing the ballast to penetrate into each anchoring tooth 12 . The arrangement of the fixing teeth 12 further provides material savings and optimization in the manufacture of the sleeper 1 .

In an alternative embodiment, the railway sleeper 1 can be configured such that the contact surface 3 protrudes beyond the fixing walls 5, 5' as shown in FIG. 12 of the present invention. Also, the fixing walls 5, 5' may be parallel or perpendicular to the contact surface 3.

This embodiment uses double support points 8, 8', where Figure 12(a) shows the sleeper 1 comprising a support groove 9 projecting from the contact surface 3 towards the hollow sector 4. foreshadow On the other hand, FIG. 12(b) illustrates a sleeper without a support groove 9 in the hollow sector 4.

Figure 12(c) shows the sleeper 1 provided with support grooves 9 from the contact surface 3 and fixing walls 5, 5', and finally Figure 12(d) shows support grooves from the contact surface 3. 9 is provided, and shows the sleeper 1 provided with fixing teeth 12 as well.

In the embodiment in which the railway sleeper 1 comprises double support points 8, 8', these points 8, 8' may protrude out of the hollow sector 4 (shown in FIG. 12), or alternatively Ideally, these support points 8 can protrude both into and out of the hollow sector 4 , as shown in FIG. 13 . In another alternative embodiment, the support points 8 , 8 ′ may project only into the hollow sector 4 . In this case, it is assumed that the second width L2 of the sleeper is the same as the first width L1.

The embodiment shown in FIG. 13 is similar to the embodiment in FIG. 12 with respect to the arrangement of the fixing grooves 9 . 13 it can be observed that the contact surface 3 does not protrude beyond the fixing walls 5, 5'.

Proposed structural embodiments for railway sleepers 1 have been presented, and their preferred embodiments are discussed below.

The thickness E of the sleeper 1 preferably assumes a value of 2 centimeters (cm), and a value in the range of 1 to 4 centimeters may be permitted. In the embodiment in which the sleeper 1 comprises fixed teeth 12, the teeth comprise a thickness E ₁ in the range of 0.2 to 0.5 cm.

Thus, with particular reference to FIG. 11 , each set tooth 12 preferably has a thickness E ₁ (thickness E _l of the set tooth) in the range of 0.2 cm to 0.5 cm.

Also, referring to FIG. 11 , the height h ₁ of each fixed tooth 12 assumes a preferred value of 0.5 to 2.0 cm.

For any of the proposed embodiments for the railway sleeper 1, the first width L ₁ is preferably equal to 24 cm, so values in the range of 18 to 30 cm are permissible.

Embodiments using double support points 8, 8' (projecting in and out of hollow sector 4) set a second preferred width L2 of 32 cm, such that the second width L2 (double support point) is Values in the range of 19 to 48 cm are acceptable if greater than the first width L1 (simple support point).

In an embodiment in which the double support points 8 and 8' protrude only into the hollow sector 4, the second width L2 will be assumed to have the same value as the first width L1.

Regarding the width of the double support points 8, 8', referred to as the third width L3 (Figs. 4, 8, 11 and 14), the latter is preferably equal to 6 cm (Figs. 4, 8 and 11) , values in the range of 1.5 to 12 cm are acceptable. For the embodiment shown in Figure 14, there is a preferred third width L3 of 10 cm, where a range of 2 to 20 cm is acceptable.

Regarding the height of the sleeper 1 proposed in the present invention, it is referred to as the first height H and is preferably equal to 19 cm for any proposed embodiment, so 14-20 cm is acceptable.

In the embodiment using the support groove 9 , this element protrudes from the contact surface 3 by a value ranging from 0.5 to 19 cm, setting the height h3 of the fixing groove as shown in FIG. 1 . It is clear that the upper end of this range represents an embodiment in which such a groove extends along the entire height of the hollow sector 4 ( FIGS. 5 and 6 ).

The width of the fixing groove, referred to as L4, assumes a preferred value of 0.5 to 3.0 cm.

For support grooves 9 protruding from the fixing walls 5, 5', the maximum limit of the height h3 must be reduced to the value used for the thickness E of the sleeper 1.

The coupling of the fixing walls 5, 5' with the contact surface 3 and the double support points 8, 8' can be carried out at right angles as shown in the previous figures, alternatively in the embodiment shown in Fig. 15 As in, it can be performed by segments of curvature.

The same thing happens with the embodiment of the support groove 9 suitable to be arranged orthogonally to the contact surface 3 and the fastening walls 5, 5', or alternatively it can be constructed from segments of curvature.

In order for the sleeper 1 to be able to withstand the stress in the field of application, it is necessary to use a material with a high modulus of elasticity (high stiffness), high resistance to impact, resistance to fatigue and high market availability.

More specifically and only in a preferred manner, the inner wall 13 and the outer wall 14 of the sleeper 1 are made of a first material, preferably a polymeric material, more preferably a pure polymeric material.

In a further preferred embodiment, the contact surface 3 and the fixing walls 5, 5' further form the inner wall 13 and the outer wall 14 of the sleeper 1, so that the inner wall 13 of the sleeper 1 is made of a first polymeric material; The outer wall 14 of the sleeper 1 is made of a first polymeric material.

The inner and outer walls 13, 14 are delimited by a contact surface 3 and fixed walls 5, 5' as better shown in FIG. 16 .

In Fig. 16, the outer wall 14 is represented by a solid line. On the other hand, the inner wall 13 of the railway sleeper 1 is represented by a dotted line.

On the other hand, the inner part of the walls 13 and 14, referred to as the intermediate layer 15, is preferably a composition comprising the first material, more preferably polypropylene with glass fibers, still more preferably a mass of glass fibers. preferably from 5% to 40% (by weight of the composition) of the composition, and even more preferably from 33% to 37% by weight of the glass fiber composition. However, it is not limited thereto.

It should be mentioned that it is a preferred feature of the present invention that the inner wall 13 and the outer wall 14 are made of the same material used for the manufacture of the intermediate layer 15 (polypropylene in this case). Accordingly, walls 13 and 14 may be made of a material other than that used for layer 15, as long as they provide the necessary adhesion to the pieces.

These preferred properties of the material of the proposed sleeper 1 in which the inner wall 13 and the outer wall 14 are preferably made of polypropylene and the intermediate layer 15 is made of a composition of glass fibers and polypropylene are shown in FIG. 16 . Not only the illustrated embodiment is valid, but all structural embodiments proposed for the railway sleeper 1 are valid.

The thickness of one of the inner and outer walls 13 and 14 is preferably in the range of 0.005 to 0.05 cm, while the thickness of the intermediate layer 15 is one of the inner and outer walls 13 and 14 at the thickness E of the railroad bed. can be obtained by subtracting the thickness of

It is important to point out that the use of a composition of polypropylene with glass fibers in the intermediate layer 15 should only be regarded as a desirable feature of the present invention, in order to allow the bending modulus of any material (composition) to be greater than 5000 MPa. Finally, it should be understood that the bending modulus must be measured (determined) according to the standard ISO 178.

It is also important to emphasize that the inner wall (or inner layer) may optionally not be included. Similarly, the outer wall (or outer layer) may optionally be absent. Therefore, the sleeper 1 can be made only with the middle layer without inner and outer walls. 24 shows an embodiment in which the sleeper is made only of an intermediate layer.

In the embodiment of FIG. 24 , the railway sleeper 1 will be made only of the material of the middle layer 15 . That is, preferably, the intermediate layer is polypropylene and glass fibers, more preferably preferably in the range of 5% to 40% (by mass), more preferably 33% to 37% by mass of glass fibers in relation to the mass of the composition. It is made of polypropylene with However, it is not limited thereto.

The manufacture of the sleeper 1 using a composition comprising polypropylene and glass fibers is to be considered only as a preferential feature of the present application, so that any material (composition) with a bending modulus of 5000 MPa can be used for the sleeper 1 It can be used in manufacturing, and the bending modulus is measured (determined) according to ISO 178. In a preferred embodiment, the material is a polymer composition. The polymer composition may include polyolefins, polyesters, polyamides, polyurethanes, and mixtures thereof, among other polymeric materials, with or without the addition of additives and/or fillers. In one or more embodiments of the present invention, the polymer composition may be of renewable or fossil origin. In other embodiments, the polymeric composition may include new polymers, recycled polymers, or mixtures thereof.

Consequently, the present application teaches the possibility of making sleepers from a composition, more preferably a polymer composition, more preferably comprising polypropylene and glass fibres, having a bending modulus of at least 5000 MPa.

In addition, the polymer composition may include pigments, flow promoters, process aids, lubricants, antistatic agents, clarifying agents, nucleating agents, beta-nucleating agents, glidants, antioxidants, antacids, light stabilizers such as HALS, IR absorbers, sunscreen additives, Fillers that alter various physical and chemical properties when added to a polymer composition, including one or more polymer additives such as bleach, inorganic fillers, organic and/or inorganic dyes, antiblocking agents, flame retardants, plasticizers, biocides and adhesion promoters and additives. The polymer composition according to the present invention comprises glass fibers, carbon fibers, carbon black, silica powder, precipitated calcium carbonate, calcium carbonate, talc, titanium dioxide, clay, polyhedral silsesquioxane oligomers (POSS), calcium carbonate, metal oxide particles and It may be loaded with a filler which may include nanoparticles, inorganic salt particles and nanoparticles and mixtures thereof.

Embodiments in which the sleeper is made only of an intermediate layer can be applied to any of the structural configurations mentioned in this application, including configurations that include a support surface 3'.

In a possible embodiment of the present application, the inner layer 13 may optionally be included in the railway sleepers 1,1'. In this case, the sleeper 1 will preferably be made of a polymer composition comprising polypropylene and glass fibers and only its inner layer 13 will be included, preferably via co-extrusion, as shown in FIG. 25 of the present application. made of polymeric material.

The polymeric material may be selected from polyolefins, polyesters, polyamides, polyurethanes and mixtures thereof, among other polymeric materials. The polymeric material may be of renewable or fossil origin and may include new polymers, recycled polymers or mixtures thereof. Preferably, the polymeric material may be selected from polypropylene, polyethylene and mixtures thereof. More preferably, the polymeric material is polypropylene with or without the addition of additives and/or fillers.

Similarly, an outer layer 14 may optionally be included, preferably through co-extrusion. In this case, the sleeper 1 will preferably be made from a polymer composition comprising polypropylene and glass fibers, and only its outer layer 14 will be made of a polymer material as shown in FIG. 26 . The polymeric material may be selected from polyolefins, polyesters, polyamides, polyurethanes and mixtures thereof, and other polymeric materials. The polymeric material may be of renewable or fossil origin and may include new polymers, recycled polymers or mixtures thereof. Preferably, the polymeric material may be selected from polypropylene, polyethylene and mixtures thereof. More preferably, the polymeric material is polypropylene.

It is noteworthy that these polymeric materials used for the inner or outer layer may also contain the previously mentioned fillers and additives.

Obviously, the embodiment of FIG. 25 or 26 can be fixed using any of the techniques mentioned in this application.

To fix the proposed sleeper 1 (including inner and outer walls or made only of intermediate layers) to the rails 2, 2', a fixing block 10 is placed in the hollow sector 4 of the sleeper 1 It should be. These blocks have the main function of enabling the installation of a fixing device for fixing the rails 2 and 2' to the sleepers and the installation of tire funds. More specifically, these blocks 10 prevent lateral movement of the railway and the part of the sleeper 1 below the rails 2, 2', i.e. the part of the sleeper 1 is placed on the contact surface 3 of the track. It should be placed on the opposite side of the dot.

18 illustrates a side view of a railroad network in which sleepers 1 proposed in the present invention are used. In this figure, it is observed that the sleeper 1 is each of the rails 2 and 2' fixed to the contact surface 3 by the support plate 20 and the tire fund 21.

Within the hollow sector 4 of the sleeper 1, when the sleeper is fastened to the rail network, it allows the ballast of the railway to penetrate the hollow sector 4, in which the ballast is compacted. Accordingly, it can be seen that greater stiffness will be achieved in the ballast/sleeper system.

18, it can be seen that a fixing block 10 is disposed under each rail 2, 2', and this block 10 is composed of a solid block, made of wood, recycled material, concrete, polyethylene, It can be made of polypropylene, and can also be made of a polypropylene composition with glass fibers, the same material as used for the manufacture of the sleeper 1. In a preferred embodiment, the fixing block 10 is made of polyethylene.

Such a fixed block 10 can be manufactured by various processes such as extrusion, press-fitting, injection, drawing, etc., which use a large block to obtain the final shape of the piece.

For better fastening of the block 10 to the sleeper 1, a fastening element, preferably consisting of a hexagonal screw 26, can be arranged transverse to the sleeper 1, as shown in FIG. 19 . there is. 20 and 21 show the proposed shape for the fixing block 10 . It is important to mention that the proposed structural embodiment for the railway sleeper 1 allows the use of any embodiment of the anchoring block 10 .

The preferred dimensions of each proposed fixing block 10 are described as follows.

Referring to Fig. 20(a), a larger base preferably represents 60 cm, so values in the range of 50 to 80 cm are acceptable.

A smaller base has a preferred value of about 40 cm, and a preferred height of 15 cm, so values in the range of 13 to 17 cm are acceptable, with a preferred depth equal to 20 cm for both height and width.

The preferred value for the fixed block shown in Fig. 20(b) is 15x13x20 (width x height x depth), while the preferred value for the embodiment shown in Fig. 20(c) is 7.5 cm for the small base and 7.5 cm for the large base. For the base it is 15 cm, the preferred depth is 20 cm, the preferred height is 13 cm.

The proposal illustrated in Figs. 20(d) and 20(e) discloses a fixing block 10 made by an injection process. It is noted that the block 10 shown in these drawings includes a number of structures 27 designed to support the load taking into account the arrangement of the rail cars.

Thus, the structure 27 combines resistance and light weight, and establishes a new possibility of arranging the fixed block 10. It can be seen that the block 10 disclosed in FIGS. 20(d) and 20(e) further includes a pre-designed orifice 28 for placement of suitable screws. It should be noted that the arrangement and shape of structure 27 should not be limited to the embodiment shown in FIGS. 20(d) and 20(e).

Additionally, any of the anchoring blocks 10 discussed herein and disclosed in FIGS. 20(a), 20(b), 20(c), 21(a) and 21(b) may be made by an injection process and , thus constructing a structured block (using structure 27).

Regarding the dimensions of the fixing block shown in Figs. 20(d) and 20(e), preferably the same values already described for the fixing block 10 shown in Fig. 20(a) can be used.

The structural embodiment of the fixed block shown in Fig. 21(a) has a larger base, preferably 60 cm, so that values in the range of 50 to 60 cm are acceptable, and the preferred height is 15 cm, with values ranging from 13 to 60 cm. 17 cm is acceptable, and a preferred depth is 20 cm, while the width of each base adjacent to cavity 24 is preferably 7.5 cm.

Finally, the proposal illustrated in FIG. 21(b) exhibits the same values for larger base, height and depth as the values of embodiment 21(a), and for each smaller base adjacent to cavity 24. A preferred width of 15 cm is indicated. It should be understood that the dimensions mentioned above are given as an example and without limiting the invention.

As an alternative to the use of the fastening block 10, by means of the already existing cast iron plate 25 using conventional fastening elements 23 such as screws, press washers and nuts and still the existing plate (plate 25) The sleeper 1 can be fixed by a metal plate 22 (preferably made of steel) fixed thereto.

This fixing configuration is shown in FIG. 22, where FIG. 22(a) shows a smaller size metal plate 22 compared to that shown in FIG. 22(b). The embodiment shown in Figure 22(b) increases the strength of the sleeper 1 by being completely arranged between the rails of the railway network. It should be understood that the number of metal plates 22 used is not limited to the number shown in FIG. 22 .

In addition to the proposed structural embodiment for the railway sleeper 1 defining the hollow sector 4 and its free part 17, the invention also relates to a railway sleeper 1' further comprising a bearing surface 3'. suggest molding.

The support surface 3' is opposite the contact surface 3 and is adjacent to the fixing walls 5, 5'. In this way, the hollow sector 4 of the sleeper 1' is delimited from the association of the bearing surface 3' and the contact surface 3 and by the fixing walls 5, 5'. Thus, in the embodiment shown in FIG. 17 , the sleeper 1 ′ does not include a free part 17 , since the hollow sector 4 is also delimited by the bearing surface 3 ′ .

Other characteristics and embodiments proposed for a railway sleeper 1 comprising a free part 17 are shown in FIG. 17 and are also valid for the embodiment of a railway sleeper 1′ comprising a bearing surface 3′. that should be pointed out

For example, reference to the inner wall 13 and the outer wall 14 in the railway sleeper 1' provided with the bearing surface 3', as well as the use of the materials and constructions already mentioned when describing the railway sleeper 1. this is valid Reference to the use of the support block 10 is also valid in this embodiment. In this regard, FIG. 23 shows a further possibility of fixing the sleeper 1 ′ in which metal plates 22 ′ are used (the number of metal plates 22 ′ does not limit the number shown in the figure). The explanation made above in Fig. 22(a) regarding the increase in intensity in 1) is also valid for the expression in Fig. 23(a).

Also, as observed in the embodiment shown in Fig. 17b, the railway sleeper 1' has a support groove 9 protruding from at least one of the contact surface 3, the support surface 3' and the fixing wall 5.5'. ).

Also, as observed in Fig. 17(c), the contact surface 3 can protrude past the fixing walls 5, 5' together with the support surface 3' proposed in this embodiment.

17(c) and 17(d), the fixing tooth 12 as previously proposed for the embodiment of the railway sleeper 1 in which the hollow sector 4 does not comprise a bearing surface 3'. ) can be seen.

In the embodiment shown in Fig. 17, the simple support points 7 and 7' are such that the contact surface 3 and the support surface 3' are shown in Figs. 17(a), 17(b) and 17(d). It should be understood that the proposal does not protrude past the fixed walls 5, 5'.

On the other hand, the double support points 8 and 8' are proposed in which the contact surface 3 and the support surface 3' protrude beyond the fixed walls 5 and 5', as in the embodiment proposed in FIG. 17(c). It should be understood.

In summary, except for the difference in the shape of the hollow sector 4, the sleeper 1' includes all the previously mentioned properties for the sleeper 1.

It is important to note that the embodiment shown in the drawings of the present invention is a preferred embodiment for the railroad 1,1'.

Thus, taking into account both the sleeper 1 provided with a free part 17 and the sleeper 1' with a support surface 3', features not explicitly shown in the drawings presented but disclosed in the drawings are taken into account. It is acceptable to propose embodiments that are used in combination.

Consider, for example, the embodiment shown in FIG. 17 , although the drawing does not explicitly illustrate this embodiment, a railway sleeper 1′ using fixed teeth 12 and support grooves 9 It will be accepted to suggest structural embodiments for

The proposed structural form for the railway sleeper 1, 1' of the present invention is preferably obtained by means of an extrusion/coextrusion process. This process is performed by conventional extruders provided with feed points, thread cannons, matrices, straighteners and reducers, for example.

Since the structural embodiment of the extruder does not represent a preferred aspect of the present invention, an extruder known from the prior art can be used for shaping the proposed railway sleeper 1, 1'.

On the other hand, it is necessary to follow the determined parameters and extrusion process steps for accurate molding of the sleepers 1, 1', and these parameters and steps are described below.

Generally speaking, during the extrusion process, it is necessary to allow uniform cooling of the entire thickness of the piece and compaction of the composition used (the structure forming the sleeper 1,1') in the straightener of the extruder.

The proposed process involves an initial step of adding the composition used (preferably polypropylene with glass fibers) to the feeder of the extruder, followed by adjusting the temperature parameters of the head (melting zone) to meet the properties of the material. do.

Simultaneously with the above step, the first pure polymer material (pure polypropylene without glass fibers) must be added to the extruder and melted.

Then, simultaneously (in the same head) the (pure) molten polypropylene must be added to the extruder together with the composition of the polypropylene with glass fibers.

After that, the composition of polypropylene with glass fibers is coated with pure polypropylene, so that the inner wall 13 and outer wall 14 of pure polypropylene and the intermediate layer 15 of polypropylene and glass fibers are arranged. should establish Thus, the first layer (layer (A)) consists of a determined material (in this case pure polypropylene), the middle layer (layer (B)) consists of another material, in this case a polypropylene composition with glass fibers, and the third The layers set up a structure similar to the extrusion process known as ABA, again composed of material A, pure polypropylene.

It should be pointed out that it is a desirable feature of the present invention that the inner wall 13 and the outer wall 14 are fabricated from the same material used to fabricate the intermediate layer 15, in this case polypropylene. Accordingly, walls 13 and 14 may be made of a material other than that used for layer 15, as long as these walls obviously provide the necessary adhesion to the piece.

Following the description of the proposed steps, after melting the structure in the cannon and screw of the extruder, the molten structure is extruded in a matrix whose primary function is to shape the structure into the desired shape.

Then, upon exiting the matrix, the structure passes through a straightener provided with a water cooling system. Besides helping to cool the piece, the cooling system aims to keep the molten structure in its final form.

Upon exiting the straightener, the piece enters a system for controlling the speed of the extruder, limiting the flow rate of the process and enabling compaction of the structure 5 within the straightener to avoid blistering and material loss. Finally, the molten structure is cut to the desired size.

The use of a polypropylene composition with glass fibers in the intermediate layer 15 should be considered only as a desirable feature of the described process, which allows all materials (compositions) to have a bending modulus of at least 5000 MPa.

Further, the composition of the polypropylene with glass fibers preferably used contains glass fibers preferably in the range of 5% to 40% by mass, more preferably 33% to 37% by mass.

Depending on the desired shape of the sleepers 1, 1', the straightener of the extruder can be configured as a straightener with or without vacuum. For straighteners without vacuum, we suggest a preferred length of 0.3 to 0.5 m, while for straighteners with vacuum, we suggest a preferred length of 1 to 4 m and a cold chamber vacuum of 0 to 0.4 bar.

It is pointed out that for shaping the railway sleeper 1 in which the hollow sector 4 is defined by the free part 17, a vacuum-free straightener is preferably used.

On the other hand, a straightener with vacuum is preferably used for shaping the sleeper 1' in which the hollow sector 4 is defined by the bearing surface 3'.

Additionally, the following preferred parameters are suggested for the extruder.

- extruder temperature, preferably in the range of 220 ° C to 250 ° C;

- extruder current in the range of 25 to 350 A;

- head pressure preferably in the range of 15 5 to 70 bar;

- extruder speed (speed of the line) in the range of 0.1 to 0.5 m/min;

- screw rotation preferably in the range of 10 to 45 revolutions per minute (rpm);

- productivity of the extruder 5 preferably in the range from 0.1 to 0.8 k/meter;

Although the process of forming railway sleepers 1, 1' is referred to as an extrusion process, other processes such as intrusion, injection or pultrusion, as such properties are only preferred embodiments of the present invention. It should be understood that this can be used for shaping the structure.

It should also be noted that in one or more embodiments, the contact surface 3 may be a flat contact surface. In one or more embodiments, the fixing walls 5 , 5 ′ are arranged perpendicular to the contact surface 3 . In another embodiment, the anchoring walls 5,5' are parallel or substantially parallel to each other. In another embodiment, the anchoring walls 5,5' are perpendicular or substantially perpendicular to the ground. It is noteworthy that small inclinations (up to 15°) between each fixed wall and the vertical axis (the "y" axis perpendicular to the ground) are allowed. This inclination can occur both inside or outside the sleeper. 27 shows the y-axis. Here, the x-axis should be understood as the ground. It is thus understood that the tilt results in an angle of 90° ± 15° with respect to the x-axis.

For the preferred examples of the described embodiments, it should be understood that the scope of the present invention includes other possible modifications limited only by the text of the appended claims, including possible equivalents.

Claims (14)

As a railway sleeper for fixing at least one pair of rails (2, 2') of a railway network, the railway sleeper (1) has a contact surface (3) on which each of the pair of rails (2, 2') is spaced apart from each other and fixed In the railway sleeper comprising a, the railway sleeper,
A free part opposite the contact surface 3 and adjacent to the fixed wall 5, 5', including a hollow sector 4 delimited by the association of the fixed wall 5, 5' with the contact surface 3 ( 7), and the railway sleepers (1, 1') are made of a composition having a bending modulus of 5000 MPa or more. The railway sleeper according to claim 1, characterized in that the railway sleeper (1, 1') is made of a polymer composition. 3. Railway sleeper according to claim 1 or 2, characterized in that the railway sleeper (1, 1') is made of a polymer composition comprising polypropylene and glass fibres. 4. Railway sleeper according to claim 3, characterized in that the polymeric composition comprises, in relation to the mass of the composition, from 5% to 40% by weight of glass fibres, more preferably from 33% to 37% by weight. 2. Characterized in that at least a fixing block (10) or a metal plate (22, 22') is arranged in the part of the hollow sector (4) opposite to the placement point of the rails on the contact surface (3) according to any one of the preceding claims. railway sleepers made with 5. Characterized in that the contact surface (3) and the fastening walls (5, 5') form the inner layer (13) of the railway sleeper (1, 1') made of a polymeric material according to any one of the preceding claims. railroad sleepers. 5. The contact surface (3) and the fixing walls (5, 5') of any one of the preceding claims form the outer layer (14) of the railway sleeper (1, 1') made of a polymeric material. railroad sleepers. The inner layer (13) and the outer layer (14) of a railway sleeper (1, 1') according to any one of the preceding claims, wherein the contact surface (3) and the fixing walls (5, 5') are made of a polymeric material. A railway sleeper characterized by forming. 9. Railway sleeper according to any one of claims 6 to 8, characterized in that the polymeric material comprises polypropylene. 2. The method according to any one of the preceding claims, further comprising a support surface (3'), from the association of the support surface (3') with the contact surface (3) and from the fixing wall ( A railway sleeper, characterized in that it delimits the hollow sector (4) via 5, 5'). The railway sleeper according to one of the preceding claims, characterized in that the contact surface (3) is a flat surface. The railway sleeper according to any one of the preceding claims, characterized in that the fixing walls (5, 5') are arranged perpendicular to the contact surface (3). The railway sleeper according to any one of the preceding claims, characterized in that the fastening walls (5, 5') are parallel or substantially parallel to each other. 5. Railway sleeper according to any one of the preceding claims, characterized in that the fixing wall (5, 5') is perpendicular or substantially perpendicular to the ground.

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