EP0021873A1 - Block for railways limited in height, especially for ballastless railways - Google Patents

Abstract

The construction of steel-concrete railroad ties onto which rails are fixed is disclosed. The ties are composed of a metal saddle for fastening to the rail, comprising a tie-plate extending over a part of the upper surface of the tie and forming the zone for attachment and support of the rail. The tie-plate further extends into the tie through ribs sealed in the concrete of the tie and constitutes at least part of its reinforcement.

Description

The present invention, due to the collaboration of Mr. René MUNIER, relates to the construction of a block of concrete-steel railroad tracks where the rails are supported on reinforced concrete blocks, called blocks, possibly connected two by two in a crosspiece by a metal frame with the ends sealed in said blocks.

This type of block is used mainly in so-called ballast-free tracks, where the blocks rest on plates of vibration damping material, in direct support on a concrete screed, in which they are generally embedded. These tracks are in particular in rail transport networks in tunnels, where the absence of ballast makes it possible to significantly reduce the height of the tunnel.

By cons, and despite the use of reinforced concrete reducing the need for reinforcement, the reinforced concrete structure of the blocks, requires giving them a certain dimensional mass to acquire the required strength and rigidity. Account must be taken of the significant concentrated pressures on the center of the block vertical to the rail during the passage of trains, tending to make the latter work in repetitive flexions on central support which are undesirable for concrete parts.

This therefore results, in order to resist these flexions, necessarily fairly massive blocks, in particular in height, which go against the desired objective of a track assembly as low as possible.

The present invention relates to a block structure not having the above drawback, while retaining sufficient strength and being of simple and economical construction.

It is characterized in that the upper face of the block has a metal saddle ensuring the support and fixing of the rail by an upper sole extending downwards by ribs sealed in the concrete of the block and forming a frame.

Advantageously, the saddle will have a general shape of an inverted U whose two vertical wings will be embedded in the concrete of the block. The upper sole will cover most of the surface of the block.

It follows from this structural combination of a metal frame in the form of a saddle covering the concrete block in which it is sealed by its wings that most of the bending forces exerted by the concentrated rail pressure will be supported by the metal structure. very rigid U-shaped saddle, under which the concrete of the block will work mainly in compression. The height of the block can therefore be reduced as much as possible. In practice, it will only have to be slightly higher than the wings of the saddle, enough to ensure their correct sealing, and transmit the pressure exerted by the saddle uniformly to the damping plate on which the block rests.

The saddles can be made from steel plates cut and folded into a U. The wings of the U can have a decreasing height from the middle to the ends, thus with a classic form of beam working in bending. Conventional round iron reinforcements may possibly be added to the saddle, for example by pinching the external faces of the wings of the U by their external frame.

According to a preferred embodiment, the saddle will be made of cast iron, its shape allowing an economical molding without coring, the molding making it possible to directly obtain from the foundry the fixing holes and the setting stops of the rail fastening devices, as well as a network of additional ribs making it possible to reinforce, if necessary, the support beam formed by the saddle, as well as its sealing in the concrete of the block. Thus, more generally, the low rail track block of the reinforced concrete type according to the invention is characterized in that this reinforcement is essentially constituted by a metal saddle of which an upper sole receives the support and the fixing of the rail and is extends downward through ribs sealed in the concrete of the block and forming a reinforcement there.

The saddle preferably has the general shape of an inverted U whose base or sole is supported and whose two wings are embedded in the concrete of the block.

These wings or ribs have a decreasing height from their support area of the rail towards their ends, giving the saddle the shape of a beam of equal resistance.

The saddle can be made of molded metal such as cast iron, the rail support sole then being stiffened by a network of ribs obtained by molding, these ribs crisscrossing for example the lower surface of the sole.

This sole will advantageously be bordered by a peripheral rib comprising external ribs at the points of connection with the internal grid ribs, on the longitudinal edge of the sole, to increase the anchoring of the reinforcement.

According to another type of construction, the saddle will be a steel plate cut and folded into a U-shaped profile.

The two wings of this U-shaped section can be embedded by wedging in the external frame of a reinforcing reinforcement in a flat grid formed of round concrete iron.

The support stops and the fixing holes of the rail fasteners will be fitted. in the sole of the saddle and produced, depending on the type of construction, either directly by foundry, or by cutting, embedding and / or welding of added elements.

• - La figure 1 représente en coupe longitudinale axiale I - I un blochet selon l'invention dans sa version préférée avec une selle en matériau coulé en fonderie.
• - La figure 2 représente le même blochet en vue de dessus.
• - La figure 3 représente le même blochet en coupe transversale III - III.
• - La figure 4 représente un blochet selon l'invention dont la selle est réalisée à partir d'une plaque d'acier découpée et pliée en U, en coupe longitudinale IV - IV.
• - La figure 5 représente, en vue de dessus, la disposition de la même selle dans le même blochet.
• - La figure 6 représente, en coupe VI - VI, les sections transversales de la selle et du blochet.

Examples of embodiments of the invention will be described below with reference to the accompanying drawings, in which:

• - Figure 1 shows in axial longitudinal section I - I a block according to the invention in its preferred version with a saddle of material cast in foundry.
• - Figure 2 shows the same block in top view.
• - Figure 3 shows the same block in cross section III - III.
• - Figure 4 shows a block according to the invention whose saddle is made from a steel plate cut and folded in a U, in longitudinal section IV - IV.
• - Figure 5 shows, in top view, the arrangement of the same saddle in the same block.
• - Figure 6 shows, in section VI - VI, the cross sections of the saddle and the block.

In FIG. 1, a rail 1, fixed in the usual way by fasteners 2 rests on a sole 3 forming the upper plate of a saddle 4 made of cast material such as cast iron. Said sole extends vertically downwards by a network of ribs 5, sealed in the concrete of a block 6. The sole 3 and its network of ribs 5 give the saddle 4 a very resistant and rigid ribbed beam structure in flexion .

The sole 3 has reliefs 7 forming the support stops for the rail fixing system and orifices 8 for passage and for fixing the bolt heads of the rail fasteners 2.

Two different types of fasteners are shown on either side of the rail in Figures 1 and 2, to illustrate the adaptability of this type of block to different fastening systems.

These Figures 1 and 2 show a network of ribs 5 squaring the bottom surface of the sole 3 and slightly protruding at 9, their junction with a peripheral rib of the sole 3, which increases the anchoring of the sole in the concrete block 6 and avoids any other conventional auxiliary frame. The block 6 is shown equipped with a liner 10 and a sole 11 of the type used for damping vibrations in tracks without ballast.

According to another embodiment of the invention, when this technique turns out to be more advantageous according to the industrial means available, the saddle 4 can be made of thick sheet metal cut and folded into a U as shown in FIGS. 4, 5 and 6 where , for the sake of simplification of the drawings, the rail fastening systems 1 have not been shown, but will be fitted out with suitable holes in the sole 3 and stops which can either be wedged in such holes, cut directly, or made up of metal studs welded to this sole according to the types of fastening used.

The inherent limitations of this embodiment limit the ribs 5 to two longitudinal ribs giving the saddle a U-shaped beam. These longitudinal wings may, as in the previous case, have a decreasing height from the middle to the ends in a shape of equal classical resistance for such beams working in bending. This limitation to the two longitudinal ribs can be compensated, if necessary for heavily loaded railways, by a reinforcing reinforcement in conventional round concrete iron, but appearing, as shown in Figures 4 and 6, as a flat grid 12 may come get stuck, by its outer frame 13, on either side of the ribs 5, taking advantage of their residual folding inclination. This wedging at 14 allows the reinforcement 13 to be held in place during the pouring and setting of the concrete.

It can be seen that in the two embodiments described, the concrete block 6 has a height reduced to the strict minimum for coating the lower part of the saddle 4 and that its role is limited to transmitting by simple compression, a constraint for which this material is well suited, the concentrated pressures of the rail 1, received through the saddle 4, to the damping plate 11, in the form of a uniformly distributed pressure.

Claims (5)

1, Lowered railroad block of the concrete type reinforced by a metal saddle of general shape of an inverted U whose base or sole (3) is supported and whose two wings (5) are embedded in the concrete of the block ( 6), characterized in that the upper sole (3) of the metal saddle (4) which receives the support and the fixing of the rail (1), extends downwards by ribs (5) sealed in the concrete of the block (6) and forming an armature therein, said sole covering most of the surface of the block. 2. Block according to claim 1 characterized in that the wings or ribs (5) have a decreasing height from their support area of the rail (1) towards their ends, giving the saddle (4) a beam shape of equal resistance. 3. Block according to any one of the preceding claims, characterized in that the saddle (4) is made of molded metal, the sole (3) supporting the rail (1) being stiffened by a network of ribs (5) squaring the bottom surface of the sole (3). 4. Block according to claim 3 characterized in that the sole (3) is bordered by a peripheral rib comprising external ribs (9) at the points of connection with the internal grid ribs, on the longitudinal edge of the sole. 5. Block according to any one of claims 1 or 2 characterized in that the saddle (4) is a steel plate cut and folded into a U-shaped profile, the two wings (5) are fitted by wedging (14) in the outer frame (13) of a flat grid frame (12) formed of round concrete iron.

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