Patent Grant
12054890
This application claims priority, under Section 371, and/or as a continuation under Section 120, to PCT Application No. PCT/HU2019/000022, filed on Jun. 25, 2019, which claims priority to Hungarian Application No. P1800227, filed on Jun. 27, 2018.
The invention relates to a sleeper, particularly to a railway sleeper.
Improving of railway transport have led to a rapid increase of train velocity and vehicle axle loads, putting increased loads on the track and on the vehicles. Besides that, intervals without train traffic that are available for track maintenance have become much shorter.
To allow for such a huge performance increase in rail traffic (both freight and passenger), in addition to fulfilling the relevant safety regulations it is also required that the vehicles have good high-velocity ride quality and stability, and that the tracks withstand the increased loads to a sufficient degree.
It follows from the above that with increasing loads the dynamic forces exerted on the railway superstructure also increase; the corresponding energy values are proportional to the square of velocity. One of the ways of providing good energy transfer is the construction of so-called concrete plate or asphalt-superstructures (instead of applying conventional crushed-stone ballast) that are dimensioned for higher forces and have increased rigidity. However, the construction costs of such track structures are typically higher. Such construction costs can be primarily justified—and the investment can even have a remunerative investment in the short or medium term—in the case of tunnels or very high-velocity (v>250 km/h) lines.
In the case of other railway tracks, in non-inner-city sections of conventional, suburban, urban or public road railway (tramway) lines, approaches applying crushed stone ballast are often preferred even nowadays. In order to counter the typically aggressive, corrosive effects of the urban environment, and to assume the increased traffic loads, the tracks are preferably engineered with higher structural reserve factors. As with other structures subject to high loads, this can involve applying higher-weight rails—nowadays, rails with typical specific weights of even 54-60 kg/m—a higher (thicker) ballast, a substructure-reinforcing layer, sleepers of higher weight capable of providing greater ballast resistance, and also resilient components.
In addition to the dynamic effects of moving vehicles, more extreme weather conditions may also have adverse effects on the geometry of the tracks and their prolonged structural stability. Along straight sections of gapless tracks, due to extreme thermal effects, there can occur significant thermal expansion (dilatation) forces and stresses in rails with greater cross-sectional area. These forces are transferred to the crushed stone ballast, and eventually to the earthwork, by the sleepers, via the rail fastenings securing the rails to the sleepers. If this force exceeds the maximum lateral ballast resistance of the track structure, the rails undergo an abnormal and permanent displacement (“jumps out”), resulting in a pronounced wave-shaped distortion of the geometrical shape of the rail that poses a risk of accident.
The tracing of the crushed stone-ballast tracks of suburban and urban railway lines needs to be adapted to the more tightly and densely built-up environments. This is also reflected in the need for building curves with lower radius. In the case of curves with a relatively low radius of a few 100 meters (typically R=100-300 m), the radial displacement of the curve due to the winter-summer temperature differential can cause radial displacements of approximately 10 cm in the case of jointed tracks, but especially in the case of tracks with gapless construction. This condition poses a danger to traffic safety, reduces the allowed velocity, and results in significant extra maintenance costs for the operator of the track. This applies especially to conventional tracks with wooden sleepers (ties). Experience indicates that, because the material of the wooden sleepers is softer than the stones in the crushed stone ballast, the stones are pressed into the bottom side of the wooden sleeper. This has a favourable effect as far as the lateral ballast resistance of the track is concerned, because it improves the “cooperation” of the sleepers and the stones, they hang on each other. However, this effect is significantly diminished after the vehicle has passed. Because the weight of wooden sleepers is much lower (⅓) compared to concrete sleepers, it is more preferred to apply the higher-weight concrete sleepers because they provide greater stability even without vehicle load. Lateral ballast resistance is also provided by the friction between the lateral walls of the sleepers and the stones of the gravel ballast. This is more favourable in the case of concrete and steel sleepers than wooden sleepers because the friction coefficient between the impregnated material of the wooden sleeper and the stones is much lower. As a third factor of lateral ballast resistance, the mass of the crushed stones to be displaced by the end faces of the sleeper also has to be taken into account.
In the case of wooden sleepers, reinforced concrete sleepers and steel sleepers configured in a conventional manner, i.e. with parallel lateral walls and without a narrowed middle section, differences in lateral ballast resistance are the result of almost exclusively the differences in sleeper weight.
Tracks constructed utilizing conventional sleepers are characterised by a relatively low “frame rigidity”, which can be increased only to a small extent by the more careful choice of rail fastenings (rail anchoring). This characteristic also deteriorates the possibility of effectively providing lateral ballast resistance along the longitudinal extension of the track.
In order to lengthen the intervals between the necessary maintenance works of the railway superstructure, it is required to prevent the restructuring of the crushed stone ballast to the greatest possible extent, to prevent the ballast stones from being crushed, and to prevent the displacement of the sleepers and the overloading of the substructure, thereby stabilizing track geometry. This holds true especially for curves with a lower radius, but also for longer straight sections of gapless tracks comprising large cross-section rails.
A number of approaches are known for increasing the length of maintenance-free intervals between maintenance works. One type of the approaches involves the application of sleepers having wider bottom sides (support surfaces). The description published in EP 1 767 696 A1 discloses such an approach, comprising a wide sleeper made of tensioned reinforced concrete. In this approach, a widened variant of the conventional sleeper having a single rail fastening on each side, is applied that has a dual diapered shape, and has a variable cross section along the longitudinal axis (as far as its width and height are concerned). This configuration allows for the application of conventional tamping machines during track adjustment works.
A reinforced concrete sleeper with a similar configuration is disclosed in EP 1 055 777 A2, wherein the sleepers are so wide that they almost contact each other, so there is not enough room between them for performing conventional tamping/adjustment works. For the tamping/adjustment of such sleepers a specially modified machine is required that is capable of performing tamping at the front side of the sleepers, which significantly increases costs and reduces the flexibility of work organisation.
A number of approaches are known for increasing the resistance against transverse displacement, and for increasing frame rigidity. In EP 1 114 221 B1 a so-called frame sleeper is disclosed. The approach is satisfactory as far as frame rigidity and lateral ballast resistance are concerned, but, due to the relatively small surface area of the bottom load transfer surfaces, can transfer overly high loads to the substructure, which is undesirable. The grid arrangement of the rail fastenings has non-uniform spacings, which poses problems for the machines performing adjustment, and also generates large bending stresses in the structure, potentially resulting in an increased tendency to crack, especially at the corners of the neck members interconnecting the two transverse beams.
A similar approach is presented in the patent description EP 1 573 133 B1 that also discloses a frame-type sleeper. This approach also has highly varying cross-sectional dimensions, which adversely affects the internal stress distribution of the structure. This approach also has the disadvantage that the transverse beams are interconnected by neck members running under the rails and parallel to them. A maximum torque location is produced in the transverse beams under the rails, while at the same time torsional loads in an opposite direction are generated by these torques at precisely the cross sectional location of the peak stress, thus “trying to break off” the connected portions of the transverse beam from the end of the neck member. Therefore, rapid failure from cracking can be predicted also in the case of this configuration.
In EP 0 555 616 A2, a prefabricated concrete plate for a railroad superstructure supporting framework is disclosed for example. The cross-sectional configuration of this approach has complex geometrical shapes, with rail fastening and the affixing of the elements to each other being performed applying dedicated means.
In the system disclosed in the patent EP 1 039 030 B1 that also applies prefabricated concrete plates, large cross-section openings arranged in a row (unilinearly) along the longitudinal axis of the plates are shown. Concrete is injected into the openings after inserting therein the steel reinforcement bars (cf.
Another approach is disclosed in the patent U.S. Pat. No. 6,764,022 B2, wherein a structure that is laid on an asphalt base layer—but that can also be interpreted as a rigid track plate—is implemented applying wide-base prefabricated reinforced concrete sleepers configured in a fashion similar to the above described approaches. In this approach, the sleepers are affixed to the base layer by “pins” injected through the wide sleeper, into cavity pockets that were previously made (by boring) in the asphalt layer Longitudinal forces are balanced out by friction between the bottom side of the pins and concrete sleepers on the one hand and the asphalt base layer on the other.
In GB 14,043, GB 2 436 842 A, JPH 09273102 A, U.S. Pat. Nos. 1,704,545 and 3,762,641 such sleeper systems or assemblies are disclosed wherein openings adapted to encompass the rails are arranged at certain portions of the sleepers. In all of the approaches according to these documents, the sleeper, so for example the plate applied for implementing the sleeper, comprises as a major structural component a portion extending under the rails. During the operation of the rail track, this portion can be subjected to high torsional loads. Sleepers with a similar structure are disclosed in AT 377 806 and AT 410 226 B.
A structural component is arranged under the rails also in KR 100702251 B1, wherein a sleeper having an essentially “tuning fork” shape is disclosed. Accordingly, in the approach according to the document, two fork-shaped portions, each extending under a respective rail, are interconnected at the middle of the sleeper by a thin and straight member. Disadvantageously, the support surface on the foundation of the sleeper according to the document is very low.
In KR 200391816 Y, essentially two adjacent conventional sleepers are joined to each other. The central interconnection portion, wherein there is arranged a sound insulation member, extends between the rails as far as the rails themselves. This approach comprises height-adjustment members applied for the sleepers.
A concrete sleeper having an essentially “H” shape is disclosed in WO 2010/114280 A2. The central portion adapted for interconnecting the two “branches” of the sleeper is disadvantageously very narrow relative to the width of the sleeper, while the branches of the sleeper are also narrow with respect to the extension measured in the direction of the rail of the opening between them, so the support surface of the sleeper according to the document is relatively small.
In KR 20160001011 U a sleeper comprising two fastening locations is disclosed wherein an additional opening is formed under the rails. A significant disadvantage of this approach is the extremely complex configuration (lateral protrusions, recesses; the sleeper has variable thickness, and has protrusions, made integral with its material, for receiving the rails).
In U.S. Pat. No. 5,312,038 a sleeper is disclosed that comprises a resilient layer arranged on a certain part.
In view of the known approaches, there is a demand for a sleeper that performs its function more effectively compared to the known approaches, and that, thanks to its configuration, permanently withstands the weather and other environmental effects, particularly the effects caused by railway vehicles running along the track attached to it.
The primary object of the invention is to provide a sleeper which is free of disadvantages of prior art approaches to the greatest possible extent. The object of the invention is therefore to provide a sleeper that performs its function more effectively compared to the known approaches, and that, thanks to its configuration, permanently withstands the weather and other environmental effects, particularly the effects caused by railway vehicles running along the track attached to it. A further object is to provide as effective vertical load transfer and transverse push force assumption as possible.
A further object of the invention is to provide a (railway) sleeper, and preferably a track plate family for railway superstructures including the sleeper that can be universally applied, i.e. with a crushed stone ballast and with other, rigid foundation types (the illustrated embodiments of the sleeper according to the invention may be called a track plate or a plate-type sleeper).
A particular object to be achieved by the invention is to provide that, in addition to utilizing it with a crushed stone-ballast implementation, the same sleeper according to the invention can also be applied as a rigid-foundation sleeper (track plate), preferably allowing for utilizing the same components for crushed stone-ballast and rigid-plate tracks at the construction of engineering structures (bridges, tunnels). Another object to be achieved is that operations related to manufacturing, transport and installation, and also to maintenance, adjustment, tamping can be performed without any modifications, in a similar fashion to conventional, crushed stone-ballast tracks, and furthermore, that vertically resilient transition sections necessarily included between crushed stone-ballast and rigid-foundation track sections can also be simply implemented applying the members of the sleeper family. These can be implemented by laying sleepers having gradually decreasing dimensions and a correspondingly fewer number of openings already in the crushed stone-ballast section. A resilience transition is thereby produced such that the support surface area of the track gradually decreases from the rigid section (larger surface area), so its vertical rigidity also decreases, and the sag (downward bend) of the track gradually increases.
The objects of the invention can be achieved by the sleeper according to claim 1. Preferred embodiments of the invention are defined in the dependent claims.
According to the invention we have recognised that in order to fulfil the above mentioned combined object targeted at reducing the frequency of the maintenance, the lateral ballast resistance and frame rigidity have to be increased, while at the same time reducing dynamic loads transferred by the sleepers to the crushed stone ballast and thus to the earthwork-top as much as possible. The unlimited increase of sleeper mass is not feasible, because, in the case of for example wooden sleepers or sleepers it is not even possible (or is exceedingly cumbersome) due to the standardised dimensions at rail fastening distances. Even with sleepers made of reinforced concrete, a number of economical issues related to the aspects of manufacturing, transport, installation and maintenance would be raised by increased material consumption. Such are the major considerations with steel and synthetic sleepers, too.
As it will be detailed below, it is therefore much more preferable to take such measures that—instead of causing a significant mass increase—involve only a small mass increase but effectively provide for a much more preferable, more favourable geometrical configuration. The ballast bed of the railway tracks constructed utilizing the prefabricated sleepers according to the invention applied in the track plate family that can be implemented according to the invention requires low maintenance, and allows a particularly effective and favourable force transfer between the crushed stone ballast and the sleeper, providing vertical force transfer along a larger surface area and an improved assumption of transverse push forces.
According to a further recognition motivating the sleeper according to the invention it has been recognised that a very favourable (lateral) ballast resistance can be provided for the track ballast made of crushed stone in case the frontal surface area of the sleeper is increased significantly, while at the same time leaving the thickness (virtually) unchanged, or even decreasing it relative to a conventional sleeper. The above described lateral ballast resistance is to be measured transversely to the longitudinal direction of the rails. This effect can be exploited to the greatest possible extent by fully omitting the gap(s) between (two or more) adjacent sleepers, i.e. by providing plates with sufficiently large frontal and support surface area. A larger sleeper surface area is desirable also in order to decrease the loads on the substructure.
However, in the case of conventional crushed stone-ballast railway tracks, in order to retain the ability to perform tamping, it is still required to provide insertion locations for the tamper hammers (adjustment hammers). Also, to achieve a more favourable stress distribution, the cross-sectional configuration is as uniform and homogeneous as possible, both in the vertical (i.e. as seen from above) and in the horizontal senses (i.e. in the direction of the plane of the sleeper). According to our recognition, therefore, the most favourable geometry can be achieved by a plate-type sleeper having a constant height dimension (by a flat sleeper), on which there are openings at the insertion locations of the tamper hammers, while the frontal surface thereof being continuous also between the rail fastenings or supports. Consequently, the sleeper according to the invention can comprise various types of rail fastening grid arrangements, i.e. can have 2, 3, 4, . . . rail fastenings arranged along the longitudinal direction. Longer sleepers can have a major role for example in level crossings or resilience transition sections of the track.
In contrast to the conventional sleepers described above, the sleeper according to the invention is typically not a “slender” structure. The known approaches are typically based on some kind of “interconnection” made between conventional sleepers, retaining the statically “slender” geometry. In a number of known approaches a connection member is arranged also under each rail between adjacent rail fastening locations, which makes it impossible to perform effective ballast tamping by conventional means. In a conventional tamping operation, the hammers move in a direction parallel to the rails. The sleeper according to the invention does not require special tamping, i.e. it is not necessary to reach under the foot of the rail, and there is also no need to apply a specially configured tamping machine undergoing a motion perpendicular to the rail axis for performing the tamping operation. If a connection member was formed also under the rails, the hammers would have to move perpendicular to the rails, i.e. rotated by 90 degrees, for an effective tamping operation. This would require a highly unique tamping machine (see for example the approach of EP 1055777 A2, wherein tamping can be performed utilizing a machine that is capable of tamping from the frontal side of the sleepers).
The illustrated embodiments of the sleeper according to the invention are therefore essentially plate-type sleepers comprising adjustment openings. It typically has a large surface area, and thus provides favourable load distribution. A special characteristic of the sleeper according to the invention is that, in addition to being utilized for crushed stone-ballast tracks it can also be applied as a prefabricated structure for concrete-plate tracks having a rigid foundation.
If the sleeper (the sleeper body thereof) is made of cast concrete (for example ferroconcrete, reinforced concrete, or even fibre-reinforced concrete—e.g. using synthetic macrofibres and/or steel fibres); the manufacturing technology of the sleepers can be identical to the manufacturing of other, conventional prefabricated tensioned reinforced concrete sleepers and concrete plates, i.e. being made (cast) “upside down” applying a mould. In such a case, a formwork for the above mentioned adjustment openings (i.e. the openings for inserting the adjustment hammers) can be made such that due to the “upside down” orientation it widens towards the bottom side and constricts towards the top side, i.e. such that when the sleeper is removed from the formwork and is flipped to the use position, the openings are adapted to widen towards the top and constrict towards the bottom. The sleeper body can also be made of plastic or steel, in the case of which such a shape can also be formed during manufacturing, but the application of concrete—in embodiments wherein the sleeper body is made of concrete—has a number of advantages (cheap and simple manufacturing, durability, etc.).
In relation to that, it has been recognised that these openings can be suitable for providing anchoring to a foundation structure such that, in the case concrete is injected in them, they form a separate layer of the foundation. Another advantage of this solution is that the anchors thus produced along the line of the rails (in this case, the opening in which concrete is injected extends transversely under the rails) provide more favourable load transfer in the longitudinal direction compared for example to the approach disclosed in EP 1,039,030 B1, thus it is operable when the reinforcement is predominantly or fully omitted, and it gives a good solution for a simpler construction with for example synthetic macrofibre and/or steel fibre dosage, which can reduce construction costs, can provide time savings and mitigate organizational problems. Accordingly, a number of preferable configurations that differ in respect of the applied manufacturing technology, installation, or the material of the sleeper (reinforced concrete, steel, synthetic) can comply with the aspects of the invention.
By utilizing more than one sleepers according to the invention, a universal system of prefabricated railway sleepers (preferably plate-type sleepers) can be provided that is adapted to preferably provide a high geometrical track stability. Applying the sleeper according to the invention, therefore, a system of sleepers (preferably plate-type sleepers) equally suited to be laid on crushed stone ballast and a rigid foundation can be provided. The present invention therefore provides a satisfactory and universal solution for constructing both crushed stone-ballast tracks and tracks with rigid foundation utilizing the same system components. It can be equally applied for uninterrupted-flow track sections or in turnouts, and also for other, special track structures (rail dilatation structures, guard rail tracks, etc.).
The various different embodiments of the invention make up a family of sleepers having a number of identical basic features. The sleeper according to the invention can be made of concrete, reinforced concrete, polymer concrete, or optionally of a new synthetic material (for example, plastic), or in certain cases also of steel.
Preferred embodiments of the invention are described below by way of example with reference to the following drawings, where
An embodiment of the sleeper (transverse sleeper) according to the invention is illustrated in
In this embodiment, furthermore, a first through-opening 14 arranged between adjacent (neighbouring) intended seating regions corresponding to the same rail laying band region, extending farther in both lateral directions than (overreaching, outreaching, overextending) one or more intended rail laying band region (has farther-extensions in both lateral directions compared to one or more intended rail laying band regions), encompassed (encircled, surrounded) by the sleeper body 10, and interconnecting the top side 15 and the bottom side of the sleeper body 10 is formed in the sleeper body 10.
The through-opening is dimensioned to allow the tamper hammers to operate in (extend into) them, at both sides of the rail laying band region. Accordingly, the through-opening is situated between adjacent intended seating regions corresponding to the same intended rail laying band region, and may extend over multiple intended rail laying band regions. In other words, such a through-opening is applied that is situated between intended seating regions that are adjacent with respect to a particular intended rail laying band region (as indicated by the above definition, the phrasing “situated between” means that it projects therein, while also extends farther than the intended rail laying band region in both directions) and correspond to one or more intended rail laying band regions; i.e. one or more through-opening is applied which extends across adjacent pairs.
The through-opening extends farther sideways in both directions than all of the one or more intended rail laying band regions (if a respective through-opening is arranged for each intended rail laying band region, then it extends out, in both lateral directions, from the region to which it corresponds). A single, common through-opening can be arranged for both rail laying band regions, or a separate through-opening can be included for each rail laying band region, as in the embodiments illustrated in
The intended rail laying band region is a region of the sleeper which can be covered, as seen from above, by a rail. For example, in the case of a sleeper having straight or indented straight sides (the latter is the sleeper according to
In relation to the concepts introduced above, reference is made to
In
The basic rail laying band region and the real (effective) rail laying band region both have a typically oblong shape (even in the case of a raster allocation of two), of which the longitudinal direction defines a basic rail laying direction (the rail extends along this direction when arranged in the basic rail laying band region, i.e. for example on sleepers arranged along a straight track section). Accordingly, in other words the condition for the width (along the length of the rail) of the sleeper is the following: in the basic rail laying direction the top side 15 of the sleeper body 10 has a width along the basic rail laying direction that allows for positioning (receiving, arranging) at least two rail fastenings (corresponding to respective seating regions) along each rail laying band region. The seating region (seating subregion, support region) is a contiguous (connected) region along which the rail is supported by (i.e. seated on) the sleeper.
Accordingly, therefore, there are at least two seating regions being arranged on the sleeper according to the invention, along the longitudinal direction of the rail laying band region (i.e. in the basic rail laying direction), that is, i.e. the connection of at least two rail fastenings are allowed along each rail laying band region. The phrasing “each seating region is applicable for a respective rail fastening” is taken to mean the following. When the rail is fastened to the sleeper, the element to be seated on the sleeper at the rail fastening is arranged along the seating regions virtually present on the top side of the sleeper body. This is situated between the rail and the sleeper, in the case of the rail fastening 18 shown in
Accordingly, therefore, the seating region can be applied for rail fastening, i.e. the rail fastening can be arranged such that an appropriate component seated on the seating region is applied.
For sleeper body configurations of other embodiments, see the subsequent figures. The above described features of this embodiment appear also in the other illustrated embodiments.
Taking into account the width of a rail, and also the requirement that there has to be room on the sleeper according to the invention for at least two rail fastenings along the rail direction width of the sleeper, according to the above it can be seen that the rail laying band regions have a shape that is elongated in the direction of the rail to be fastened, i.e. their longitudinal direction defines the basic rail laying direction.
As far as the rail fastenings are concerned, the sleeper according to the invention is configured such that—taking into account the standard rail fastening spacings—it can accommodate at least two rail fastenings (two in the embodiment according to
A rail laying band region corresponds therefore to such rails that are to be fastened to the sleeper utilizing a rail fastening (so for example not for a movable rail of a switch that will not be fastened to the sleeper). Therefore, the region over which a rail can be laid across the seating regions (that are in contact with the top side of the sleeper), and which thus overlaps with the seating region, is called the rail laying band region. This means that no rail laying band region will correspond to the movable rail of a switch, as it is not fastened to the top side of the sleeper. In a top view, a cover zone (varying as it moves) corresponds to it. Nevertheless, a through-opening is preferably also provided for such movable rails such that tamping can be satisfactorily performed also along the section under the switch.
The sleeper body is preferably symmetrical such that its axis of symmetry is parallel to the straight rails to be laid—running perpendicular to the sleeper—and is at an equal distance from them. Arranging the through-openings in a row also involves that they are arranged symmetrically with respect to this axis of symmetry. This arrangement in a row is also applicable for the side of the sleeper that lies transversely to the rail laying band region, if it has a straight or indented straight shape.
In the foregoing, the entire through-opening was described in relation to the intended rail laying band region and to the intended seating regions. By that it is meant that, seen in a top plan view (i.e. vertically projecting the rail laying band region) the through-opening in its entirety is situated between the adjacent seating regions and extends farther than the intended rail laying band region, i.e. not only the opening end thereof situated at the top side of the sleeper body, but also the second opening end thereof which is formed at the second side thereof (see the top view of
The lateral wall (side wall) of the through-opening can therefore be perpendicular to the top and bottom sides, or has a maximally low angle of inclination with respect to them (see below, for example the amount of inclination is lower than e.g. 1:10). As illustrated in the figures, the lateral wall of the through-opening can be constituted by flat faces (in this case the shape of the cross section of the opening is rectangular or rectangle-like as seen from above), but such through-openings can also be conceived that have ellipsoidal or other distorted-circular cross sections as seen in a top plan view of the sleeper. The inclination of the lateral wall can also be interpreted in this case, and it preferably falls between the specified limits (i.e. between vertical and the maximum inclination).
As with the known approaches, the rail laying band regions extend on the top side of the sleeper in the direction of the rail to be fastened. In the case of a known simple (single) sleeper, the rail laying direction is precisely the direction perpendicular to the longitudinal direction of the sleeper; with such a conventional sleeper the rail laying band region extends entirely along the top side of the sleeper. In the invention, the rail laying band region is positioned in a fashion similar to the known approaches, but in the case of the invention the rail laying band region passes also above the through-opening. The rail laying band region can also be called a rail laying region or rail laying surface band (zone).
According to the invention, the rail laying band regions can have a common through-opening or the regions can have respective mutually separate through-openings. In the case of a general sleeper located at a typical track section (i.e. at a straight or curved section without a switch), due to the larger support surface area it is generally expedient to form a separate through-opening for each rail laying band region.
However, a switch for example has a rail that is situated between the two fixed rail portions, and is sideways movable to some extent; a separate through-opening can be preferably arranged corresponding to this rail portion, preferably arranged in the same line with the through-openings corresponding to the encompassing rails. At such portions of the movable rail that cannot be displaced too far from the fixed rail, a through-opening connected with the through-opening corresponding to the fixed rail can be arranged to correspond to the movable rail (i.e. this through-opening has a greater lateral dimension than the through-opening applied in the general-purpose sleeper, which involves that this special location of the through-opening affects the dimensioning thereof). Also, such a sleeper can be preferably applied for any portion of the movable rail (and also for other track sections) that comprises a common, connected through-opening corresponding to the two stock rails and also to the movable rail between them.
Furthermore, near railroad switches such sleepers are customarily applied which extend under both parallel tracks connected by the switches. In relation to the sleeper according to the invention this means that such a (long) sleeper can be conceived that extends under two adjacent pair of rails, and through-openings corresponding to all of the individual rails being formed thereon. The portion of the rails of the switch that is situated between the two parallel pair of rails is also supported on a sleeper extending under both tracks; through-openings can also be arranged under the rails along this portion. The turnout can further comprise, at the crossing (at the point where the curved rail of the diverging branch of the turnout—of which the end extends for example as far as the left rail—crosses the other rail, which in this case is the right-hand-side rail), such a sleeper that has three separate through-openings corresponding to the fixed first rail, to the crossing, and to the pair of the diverging rail, respectively. In this case, therefore, in addition to the two through-openings corresponding to the stock rails, the sleeper comprises another through-opening (and of course has a length that allows for accommodating them, cf.
The case wherein a respective guard rail extends along the inner side of one or both “base” rails is also mentioned. In this case, a through-opening of such dimensions can be applied that extends transversely (preferably perpendicular) to the basic rail laying direction such that it also extends under the guard rail, i.e. the tamping machine can perform tamping at both sides of the unit formed by the rail and the guard rail. The guard rail therefore affects the dimensioning of the through-openings (i.e. essentially such dimensions are to be applied [see the description of
Each rail of the rail pair applicable with the sleeper is laid in a respective rail laying band region applying a customary rail fastening. An exemplary rail fastening manner is shown in
As shown in
Accordingly, typically two rail laying band regions are situated on the top side of a sleeper, each of which being adapted for connecting a respective rail (concerning sections with guard rails, turnouts or switches, etc. see above). The relative distance of the rails (i.e. the track gauge) is usually determined by regulations or standards; it tipically determines the distance between the rails and the centreline of the sleeper (along the basic rail laying direction, i.e. preferably the axis of symmetry thereof), and thus also the location of the intended rail laying band regions. The track gauge can of course vary in order to comply with the standards, or according to the chosen track type. The intended rail laying band regions are therefore such regions of the top side of the sleeper body that can be covered by or obscured by the rail, when seen from a top view (in case of the rail being laid straight or oblique, or of applying a curved rail; in the top drawing of
In
In an embodiment of the invention, a respective through-opening separated from each other corresponds to each intended rail laying band region, i.e. through-openings separated from each other are formed for each rail of the track corresponding to the sleeper.
In the illustrated embodiments of the invention, furthermore, a first opening end of the through-opening on the top side and a second opening end of the through-opening on the bottom side are arranged opposite each other. In addition to that, as it will be seen, the through-opening preferably shrinks uniformly from top to bottom (the bottom opening end is preferably a slightly shrunk copy of the top one; and, besides that, the shrinking is uniform, i.e. linear, the lateral walls can be e.g. determined by flat faces), the expediently chosen axis of the through-opening (about which axis the opening exhibits some kind of symmetry) is perpendicular to the—preferably flat—top side of the sleeper.
The sleeper according to the invention is therefore a sleeper wherein one or more through-openings adapted to interconnect the top and bottom sides are formed. The portions situated at both sides of the line connecting the pairs of through-openings or the common through-opening can also be interpreted as sleeper “branches”. It can therefore be said that these sleeper branches are interconnected by the sleeper portion lying between the openings corresponding to the two rails, and by the frontal portion terminating the sleeper in a direction perpendicular to the rail. The one or more through-openings are in all cases encompassed by the material of the sleeper, being open expediently only at the first and second opening ends.
One of the most important characteristics of the above described sleepers (preferably, plate-type sleepers) is that—depending on the raster arrangement of the fastenings and the size of the sleeper—one or more openings (through-openings) are formed therein, each of which being arranged between two rail fastenings, along the path of the rails to be fastened. The through-opening can also be called an adjustment opening. Such openings allow the operation (reaching under the track) of the hammers of the tamping machine, in the regions between the sleepers, when the sleeper is laid in crushed stone ballast (first arrangement mode), much like it is possible in the case of conventional superstructures comprising crushed-stone ballast and sleepers. A possibility of tamping between the rail fastenings is provided, independent of that a single sleeper spans on (“covers”) multiple rail fastenings (see also
By applying the same sleepers (preferably plate-type sleepers) laid on rigid foundation—as it has been touched upon above—the above mentioned through-opening (adjustment opening) has a different function.
In the sleeper according to the invention, the cross-sectional area of the through-opening increases on at least a section (on at least a part) from the bottom side towards the top side of the sleeper body. From the aspect of providing a rigid foundation (see the description of “plugging” below, which allows for making a shape-fit connection applying such a through-opening) this constitutes an advantage, but at the same time it does not have any disadvantages even if the same sleeper is to be laid on a crushed stone ballast. It is preferable to utilize such sleepers that are equally well suited for application with both types of foundation, because even in the case of the same track there can be engineering structures between the crushed-stone ballast sections, or other sections where it is expedient to apply a rigid foundation. If the sleeper can be utilized with both types of foundation, preferably only one type of sleeper has to be transported to the construction site (i.e. it is not necessary to transport there different sleepers).
In a further embodiment, the cross-section of the through-opening, being parallel to a plane corresponding to the bottom side (can be assigned to the bottom side), preferably increases uniformly (steadily, i.e. not only along a portion) from the bottom side towards the top side of the sleeper body. Furthermore, the through-opening has a rectangular or rectangle-like (nearly rectangular, for example with bevelled corners) cross-section parallel to a plane corresponding to the bottom side. It is also possible to implement the uniformly increasing cross-section of the through-opening by providing—in accordance with the oblong shape of the through-opening—a distorted circular, or other, preferably elongated cross-sectional shape.
In order to fulfil certain functions it is sufficient if the cross-sectional area increases along at least a portion, in which case the material filled into through-opening and setting therein forms a “plug” in the sleeper, i.e. the sleeper cannot be displaced upwards because the “plug” cannot be moved with respect to the foundation. It is also advantageous from the aspect of manufacturing if the through-opening has a uniformly increasing cross-sectional area, i.e. the one or more inclined walls of the through-opening have a uniform inclination. In the illustrated embodiment, all lateral walls of the through-opening (preferably also the bevelled corners) have the same inclination (this is also advantageous for formwork, i.e. for the removal from the formwork). Because too high an inclination can be problematic for tamping, expediently the inclination is not overly high. Depending on the thickness of the sleeper, the inclination can be for example between 1:20-1:10 (approximately 2.86° and 5.71° relative to the axis of the through-opening mentioned below), the inclination is to be interpreted between the axis (in general, an axis perpendicular to the preferably parallel top and bottom sides of the sleeper body) of the symmetrically configured, uniformly narrowing (the cross-sectional area increasing uniformly from the bottom side towards the top side) through-opening and the plane of the lateral wall. This range can preferably also be interpreted if not all of the walls are inclined, or the cross-sectional area increases only along a portion of the through-opening, then, only for a given portion of a particular lateral wall. The dimensioning of the through-opening allowing for the operation of tamper hammers is also suited for this type of installation, i.e. by injecting concrete.
In an embodiment, therefore, lateral walls of the through-opening interconnecting the top side and the bottom side are determined (defined) by flat lateral wall portions, the through-opening has an opening axis perpendicular to the top side, and the inclination of the flat lateral wall portions relative to the opening axis is between 1:20 and 1:10.
To put it in a slightly different way, the through-opening preferably expands from bottom to top (i.e. in a built-in state, from the base towards the rail). Thus, by injecting an appropriate material into the spatial region under the plate-type sleepers and into the opening(s), a shape-fit fastening of the sleeper is produced that adequately secures it in the longitudinal and transverse directions of the track, and also adequately prevents vertical displacement, so it is especially well suited for assuming dynamic loads caused by moving railway vehicles.
In light of the above, regarding the approach disclosed in KR 20160001011 U mentioned in the introduction the following can be mentioned. Although in the approach disclosed in the document such a through-opening can be arranged in an embodiment that extends farther than the rails in both directions (this can be seen for example in
The most important of these drawbacks is that in the known approach there is not formed a through-opening with a cross-sectional area increasing along at least a section of the opening, from the bottom side of the sleeper towards the top side thereof. The above-mentioned
There was not found any advice for a through-opening with a cross-sectional area increasing from the bottom side towards the top side of the sleeper on at least a section (like the through-opening according to the invention) either in KR 20160001011 U or in any other earlier document. In relation to that it is important to note that through-openings that differ in this aspect can be manufactured applying different types of formwork, so the configuration of the appropriate through-openings requires different manufacturing considerations (for example for “pulling off” the completed product from the formwork).
In KR 20160001011 U, a sleeper with a complex shape is illustrated (for example, with different emphasized shaped protrusions along the sides, and with a separate protruding portion for receiving the rails). In contrast to that, the sleeper body of the sleeper according to the invention is preferably a concrete plate, wherein openings are formed (preferably by providing a formwork), and of which the edges are shaped appropriately (the edges are basically straight, with typically the corners being cut off (bevelled), and with a lateral indent being preferably formed in each side lying transversely to the intended rail laying band region), however, preferably there are not made any protrusions or recesses either on the top or the bottom side of the bulk of the material thereof, so—of course disregarding the through-openings—it has a flat top side and a flat bottom side.
The sleeper according to the invention is therefore preferably shaped by the proper shaping of the sheet (i.e. the sleeper body is formed from a sheet), by which it is meant that during manufacturing proper formwork is provided for the edges of the sheet and the through-openings, but inside the formwork the sleeper is formed to have a flat sheet shape.
In contrast to the approach disclosed in KR 20160001011 U, according to the invention a reinforcement protruding from bottom side of the sleeper is preferably not applied. The reinforcement preferably applied in the sleeper according to the invention is configured such that the reinforcing components are arranged inside the sleeper (entirely, i.e. they do not protrude anywhere from the sleeper).
In
In
In
By arranging and dimensioning the through-openings 14 according to the invention, the operability of the adjustment hammers (tamper hammers) can be preferably ensured. The arrangement of the through-openings 14 essentially allows that the rail section between the two rail fastenings 18 can function as a free rail section as far as the adjustment hammers are concerned. The operation of the tamper hammers is therefore not affected by the fact that the through-openings 14 are fully encompassed by the sleeper body 10. At the same time, thanks to the configuration according to
As illustrated in
In relation to the rail fastenings see also
Bevelling of the inner (negative) corners of the through-openings is also aimed at mechanical protection, because stress cracks may start from the (sharp) corners, which can lead to the failure (cracking) or the sleeper. This can be achieved by rounding off the corners at a radius of R=1-5 cm, or by applying a flat 45° bevel which may have a length of 2-4 cm (this latter is illustrated in
As it is illustrated in
The lateral indents 20 that are shown in
In
In
In
The plane along which section A marked in
In
In
In a “floating” structure utilized for increasing track service life and for reducing noise and vibration, a resilient layer 21 can be arranged on the sleepers (so in the sleeper body 10, 30 and 60, too) at locations in contact with portions cast with concrete, for example applying a suitable elastomer sheet. This resilient layer 21 can also be included in the configuration with a crushed stone ballast, and can function as a vibration damper layer protecting the ballast. In this case the cast portions 25 are replaced by crushed stone material that allows for performing the tamping operation. In an embodiment, therefore, a resilient layer is arranged on the bottom side of the sleeper body and/or on a lateral wall of the through-opening interconnecting the top side and the bottom side of the sleeper body. In the illustrated embodiment a resilient layer is arranged at the bottom side and also at the lateral wall of the through-opening, but in other conceivable variants it is arranged at only one of them.
Therefore,
In
In
The longitudinal dimension of the sleeper body 30 (side length 42) can be obtained by multiplying a first distance 44, corresponding to the distance between the rail fastenings arranged along a rail axis 50 (the axis of symmetry of the rail), by the number of raster allocations (the number of gaps between the rail fastenings, in this example, three) and adding thereto the value of distance 58. Therefore, in
An extension 56 of the through-opening 34 measured along the longitudinal direction of the rail laying band region, i.e. parallel to the rail (the shorter side or second dimension of the through-opening that has an oblong shape when viewed from above, second inner size) is obtained by subtracting the distance 58 from the distance 44, or in other words, it is obtained as the raster allocation minus the distance 58, so typically (distance 44)−(distance 58)=(extension 56), which can therefore be between 75 cm−30 cm=45 cm, and 60 cm−30 cm=30 cm taking into account the above given values, but the value can optionally also fall outside this interval. The extension 56 is preferably between 20 and 80 cm (the upper limit can also be 65 cm), particularly preferably between 30 and 45 cm (the lower and upper limit values can be combined as desired). With these values, an appropriately large front side is obtained at the side of the sleeper body parallel to the rail. From these values it can also be inferred that by setting the distance 58 (i.e. the width corresponding to a branch of the sleeper) to 30 cm according to the above, the width of the raster allocation of two variant (measured along the longitudinal direction of the rail laying band region) will be between 90 and 115 cm, that is, the two adjacent rail fastening locations (and the respective seating regions on the rail laying band regions) are arranged on this width in case two of them are situated on the given sleeper body (as in the embodiment of
Consequently, there may be such a case wherein the distance 58 is different from the extension 56 (measured parallel to the rail), i.e. the portions (branches) of the sleeper situated around the through-opening 34 along the rail are narrower than the dimension of the through-opening 34 measured along the rail. In
In line with the above data, in an embodiment the largest extension of the second opening ends of the through-openings on the bottom side in the direction of the intended rail laying band region is 50-60% (more generally, these limits are 45% and 65%) of the distance between the centres of the adjacent intended seating regions (if the seating region is defined by a rectangular fastening plate, the distance is measured from its centre, while for example in the case of the fastening being implemented utilizing two screws the centres of the rail fastening portions and typically the centres of the seating regions are coincident with a point situated between the two screw holes at an equal distance from both). The above is of course applicable to the illustrated sleeper type that has a(n essentially) rectangular shape when seen from above. In the case of the known approaches this percentage is very high, way higher than the above specified percentage limits, i.e. therein the surface area taken by the opening from the useful support surface area of the sleeper is much larger. This condition is preferably fulfilled also in the case of the embodiments of
In
In another example, the side length 40 value is, to a good approximation, 260 cm, in which case the characteristic dimensions for a wider rail (having for example a greatest rail width of 150 mm) are: the extension 54 of the through-opening 34 measured transverse to the rail laying band region is for example between 65-88 cm (these larger dimensions are applicable for the smaller sleeper width above, with the opening dimensions of the lower-width sleeper being applicable for this wider sleeper; the extension of the through-opening measured transverse to the rail is therefore e.g. between 50 and 88 cm), the distance 46 (the width of the inner portion of the sleeper body 30) between the two through-openings 34 can for example typically be between 62 cm (with a through-opening with a width of 88 cm) and 84 cm (with a through-opening with a width of 65 cm), and the distance 52 beside the through-opening 34 being can be between 11 cm (with a through-opening with a width of 88 cm) and 23 cm (with a through-opening with a width of 65 cm). The dimensions of the extensions 54 and 56 characteristic of the through-opening can of course be applied for a variant with a different raster allocation (for example, two or other).
In an embodiment of the invention, a separate through-opening is arranged corresponding to each rail laying band region, i.e. through-openings separated from each other are formed for each rail of the rail pair corresponding to the sleeper. Besides that, preferably lateral farther-extensions of the through-openings (the through-openings, i.e. preferably the first and second opening ends thereof) from the intended rail laying band region are symmetrical with respect to the intended rail laying band region.
In an embodiment of the invention comprising a respective separate through-opening for each rail laying band region, therefore, in the case of attaching a rail, the through-openings are formed in a row extending in a transverse direction to the intended rail laying band region, the cross-section of the through-openings being parallel to a plane corresponding to the bottom side (and preferably also parallel to the top side; the plane corresponding to the bottom side is the plane which can be fitted to the bottom side, this plane coincides with the plane on which the sleeper can be placed) has a rectangular or rectangle-like shape, and the sum of the largest extensions (see the extension 54 above) of the second opening ends of the through-openings formed in a row on the bottom side in the transverse direction with respect to the intended rail laying band region is 40-70% of the extension of the sleeper body measured transversely with respect to the intended rail laying band region.
For the above cited exemplary values in particular, with a sleeper having a width of 240 cm, this percentage is approximately between 41.6% and 54.16% (for this case the limit values can preferably be 40% and 55%). For the sleeper with a width of 260 cm, this value can be approximately between 50 and 67.69% (the limits can for example be 50 and 70%, the ratios corresponding to the lower and upper limits of the two dimensions can be combined arbitrarily), i.e. taking into account the through-openings corresponding to both rails. For measuring the extension, the second opening end of the through-opening is taken into account, because they open to the bottom side supported against the foundation; so the dimensions characteristic thereof are indicated in
In line with these values, in this embodiment the support surface of the sleeper is relatively large. In the known approaches the opening has a very large width relative to the portion not affected by the openings (i.e. the percentage ratio is disadvantageously much higher than in this embodiment), so the support surface is small. With other known approaches, the support surface is small because the portion interconnecting the sleepers has a low cross-sectional area (a low surface area contacting the support surface).
The tamper hammers can be situated (in a stationary state) approximately 5-10 cm, preferably 5-8 cm from the edges of the foot of the rail, and on the other side, from the edge of the through-opening, because they can also move laterally during tamping. It is expedient to keep the hammers spaced apart by a few centimetres also from the side of the through-opening lying perpendicular to the rail (this dimension of this side can be adjusted). To provide for that, it is preferable if the through-opening has the essentially rectangular (rectangular or bevelled-corner rectangular [rectangle-like]) cross-sectional shape (as seen from above) illustrated in relation to the described embodiments. The hammers have to be taken into account having a width, measured transverse to the rail laying band region (perpendicular to the rail) at both sides of the rail to be laid, of 100 mm, 140 mm, or 2×100 mm (so 200 mm in total, and if that is too wide, one can be folded out and utilized later on as a hammer with a width of 100 mm). the dimension of the hammers measured transverse to the rail laying band region therefore preferably falls between 100 and 200 mm. Such hammers can be utilized with sleepers having the above specified exemplary dimensions of the through-opening.
Like the above described embodiment, the embodiment according to
In the case of the rigid-foundation implementation of larger-sized plate-type sleepers (such as the variants having the sleeper body 30 and 60 in
Lifting links 37 shown in
After making the necessary height/level adjustments, injection utilizing runny concrete or other appropriate material, depending on the elaborated technology, is performed (typically, concrete is applied, but other materials can also be injected to fill up the intermediate layer). With injection technologies, in order to circumvent spreading-related problems arising due to the larger bottom surface area of the larger sleepers (such as, for example, sleepers with the sleeper body 30 and 60) it can be advantageous to prepare one or more injection openings (inner injection locations) 35 and 65. In an embodiment, therefore, an injection opening interconnecting the top side and the bottom side of the sleeper body is formed in the sleeper body separately from the through-opening.
The injection opening is adapted to allow for inserting a suitable material, preferably concrete, into the layer situated under the sleeper. Accordingly, one or more injection openings—separately from the through-opening—are formed for this purpose. Besides that, the one or more injection openings can be formed anywhere in the sleeper body, however, it can be expedient to arrange the one or more injection openings at a central portion of the sleeper body, such that the material injected therethrough can spread evenly under the sleeper body. Therefore, an injection opening can be preferably arranged in the geometrical centre of the sleeper body. According to
In the embodiments of
In
In the system comprising the sleepers according to the invention components with other raster allocation, e.g. of three, of five can also be applied depending on the installation site conditions, and transport or other circumstances.
In an embodiment of the invention having a raster allocation of two the surface area supported against the foundation is preferably 20-30% larger compared to a conventional sleeper projected to a single sleeper, (the degree of increase of the surface area is of course also dependent on the cross section of the opening end of the through-opening facing the support surface). In the case of sleepers with raster allocation of three, four, five or six, with identical through-opening dimensions this increase can even be as much as 40-50% projected to a single sleeper. Applying larger blocks (with higher raster allocation) is more favourable also because of the higher ratio of support surfaces. Frame rigidity is also much higher in this case, and can even be 2-4 times higher relative to conventional sleepers.
The sleeper according to the invention can be applied with all types of standard normal or grooved rails, or with any other non-standard rail types, constrained only by the operating conditions (velocity, axle load, traffic load). These are operator-dependent issues; members of a family of sleepers can be dimensioned for such standard cases or load cases governed by regulations.
In
In
At the bottom of
Along the switch, the straight rail sections—terminating in the rails 72 continuing along a straight path—and the diverging movable rail sections—terminating in diverging rails 82 (that for example lead to a turnout)—diverge more and more from each other. Along a track section, such a sleeper body—similar to the sleeper body 10—can also be applied that comprises two through-openings, each for one of the two rails, on which the through-openings are expanded sideways with respect to the rails, such that tamping can be performed when advancing along any of the tracks (if a crushed stone ballast is applied). After a certain distance, when the rails diverge to such an extent that overly wide through-openings would have to be applied, it becomes more expedient to apply such a through-opening that extends under all rails, i.e. under the rail laying band regions corresponding to both the fixed rails and the movable rails. A sleeper body 70 that is shown in
As shown in
Before the crossing (between the curving rail of the switch and the two straight rails) and after it (the tracks are already separate) but still near the crossing it is expedient to apply an embodiment of sleeper body that is configured like the sleeper body 80, applying a preferably widened central through-opening, and arranging the other two through-openings corresponding to the outer rails, applying a sleeper having a lower lateral width before the crossing and one having a larger lateral width after it. Along the section after the crossing, where the rails are sufficiently spaced apart from each other, a sleeper body like the sleeper body 10 can be preferably applied.
As shown in
In the sleeper according to the invention, therefore, either a separate respective through-opening is formed for each rail, or a connected through-opening is formed between the rail fastening locations. When designing a track section, the locations requiring special configuration can be listed, and the appropriately dimensioned special sleepers can be manufactured for each location applying particular embodiments of the sleeper according to the invention, taking into account of course the type of rail fastening to be applied. After manufacturing the sleepers corresponding to a given track section, based on the design the intended and basic rail laying band regions and the seating regions corresponding to the rail fastenings can be assigned to the particular sleepers, i.e. their location relative to the through-openings can be determined.
In
In
For the distances marked in
A dimension 130—shown at the bottom of
According to
According to the figure, the distance 144 is composed of the regions around the rail 112 as follows. A distance 156 between each of the lateral edges of the of the foot of the rail and the centreline of the rail 112 is 70-70 mm at both sides in the example. On the left, a distance 154 between the foot of the rail 112 and the projection of the head portion 103 of the tamper hammer 102 is 110 mm in the example. On the left, the edge of the foot of the rail 112 is at a distance 152—in the example, 120 mm—from the head portion 103 of the right-hand side tamper hammer 102.
A distance 150 shown in
In
In
As shown in
In an example, the embodiment of
The dimensions of the through-opening 114 are the same as the dimensions of the through-opening 104, but it is arranged at a different position relative to the sleeper body 110 (the size of the sleeper body 110 itself is also different from that of the sleeper body 100). In the example that has already been introduced above specifying certain values, a distance 162 is 367.5 mm, i.e. the distance between the through-opening 114 and the (central) axis of the sleeper (plate-type sleeper) is smaller than in the embodiment according to
The tamper hammers 102 are arranged relative to the through-opening 114 similarly as relative to the through-opening 104, so in the example the values of the distance 136, width 142 and distance 144 seen in
As was mentioned above, the track gauge (the distance between the rails) is preferably identical in the embodiments of
In
In an example implemented according to
As illustrated in
In this embodiment, the width 188 is composed of the distances 186 at both sides, and of the width 202, which latter is the total width of the tamper hammers 122, also taking into account their head portions 123. In the example, the width 202 is 775 mm, which is divided into two distances 204 (the value of the distances 204 in the example is 387.5 mm) by the topmost point of the rail 112 (i.e. the axis of the rail 112).
In the embodiment of
In the subsequent figures the embodiments of
In
A basic rail laying band region 105 is also illustrated in
In
In
In
In
As illustrated in
In the embodiment of
The farther-extensions of the through-openings can for example be best observed in the top figures. Of these, because
Examining the values corresponding to
Of the embodiments of
In a direction transverse to the rail laying band region—due to the typical “cut-off” or bevelling of the corners of the through-openings—their largest extension can be measured at the bottom side at the central portion of the opening sides parallel to the rail laying band region, and corresponds to the length of the (longer) side—extending transversely to the rail laying band region—of the rectangle-like through-opening (because in
To characterize the amount of asymmetry it is an obvious choice to compare the difference between the first and second farther-extensions and the lateral extension of the through-opening (measured at the bottom side); however, the asymmetry can also be characterised differently (for example by measuring the lateral extension of the through-opening at the top side). If necessary, above the values related to asymmetry, and the limits specified above can be recalculated according to this alternative approach.
Using the exemplary values specified in the embodiment of
As indicated also by the exemplary values included above, in the embodiment of
As illustrated also by
The above description of the other embodiments can be applied mutatis mutandis to the embodiments of
The mode of industrial application of the invention according to the above description follows from the features of the invention. As can be seen from the description above, the invention achieves its object in a particularly preferable manner compared to the prior art. The invention is, of course, not limited to the preferred embodiments described in details above, but further variants, modifications and developments are possible within the scope of protection determined by the claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| P1800227 | Jun 2018 | HU | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/HU2019/000022 | 6/25/2019 | WO |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2020/002957 | 1/2/2020 | WO | A |
| Number | Date | Country |
|---|---|---|
| 1573133 | Sep 2005 | EP |
| 2121204 | Aug 1972 | FR |
| 20160001011 | Mar 2016 | KR |
| 20160001011 | Mar 2016 | KR |
| 2005100692 | Oct 2005 | WO |
| Entry |
|---|
| European Patent Office, International Search Report and Written Opinion in PCT Application No. PCT/HU2019/000022, Nov. 19, 2019. |
| Number | Date | Country | |
|---|---|---|---|
| 20210269984 A1 | Sep 2021 | US |
