EP0334862A1 - Cast iron sleeper with built-in rail anchors. - Google Patents

Abstract

Rail sleeper (1) made directly of cast iron, with integrated anchors (hooks) (2) intended to be used for locking on the rails. These cast anchors (hooks) (2), integrated into the crossmember (1), guarantee locking without resorting to movable fixing plates, while ensuring the spacing provided already at the casting stage. The material chosen guarantees resistance and the absence of long-term wear.

Description

Cast iron sleeper with built-in rail anchors.

This invention has, as a subject, a cast iron sleeper with built in anchorages (hooks) for rail track. It is known that - at present - the most used rail sleeper is in wood, of the most different kinds, suitably treated and processed, on which the track linking items are set.

The average life of the wood sleeper ranges between 15-20 years.

The continuous increases in costs, and the procurement difficulty - to a very large extent, it is import wood - required to replace this typical part of the track.

Futhermore, there also exists the sleeper made up of pre-compressed reinforced concrete - with built in wooden wedges - to fix - by screwing up the dowels - the anchoring plates on which the track shall be locked.

Said pre-compressed reinforced concrete sleeper has replaced wood in its function of stress distributor, but it has kept the need to separately arrange anchorages, prior to a preparation, seasoning, impregnation, and bituminization work on the sleeper; all this is definitely expensive.

There exists, even though it is going to be finally neglected, the steel sleeper, obtained by hot forging and holed for the fitting of locking items; it is not widely used both for the high cost, and for the packing of sleepers difficulty, since this type of sleeper discharges stresses on the short edges of the same, and does not totally lay on the ballast.

The subject invention - obtained by casting - allows to obtain a rail sleeper 1 with well-defined mechanical characteristics, able to meet - in a very optimal way - the necessary principles of strenght and resistance of the track to the pressure specific stresses, distributing them on a wide surface, and allowing - by using anchorages 2 obtained by casting (in a single piece, with the rail track 1 casting) - the track locking by the classical dogs and plate system.

As for the intrinsic characteristics of the material, the cast iron rail sleeper 1 of the subject has a practically unlimited life, it does not need to be imported; thanks to its structure and shape, it optimally distributes stresses; it lends the track a strenght suitable to heavy and very fast traffic; it does not require the plates anchorages arrangement, since they already are obtained by casting.

Furthermore, it has further and important advantages, with respect to the traditional types of sleepers. Already during the casting, the anticipated gauge is obtained, the anchoring (hook), being a casting product, does not shift (on the contrary to what happens with all used types: possible shifting of bolts, dowels, etc., due to vibrations and material wear); the gauge is fix and set; mainte nance is practically unnecessary; safety is maximum. We wish to state - as an example - that the shape relative to casting of the cast iron sleeper is prepared with the moulding in stop block of a sand + resin mixture. The model is removed, and the cores relative to the cast brackets are inserted. Cores vary in accordance to the anchorages (hooks) geometry, able to meet the supply required variables. The mould is painted and, after the hardening of the forming mixture, is prepared for the pouring stage.

The liquid cast iron - thanks to analyses suitable to the cast required mechanical characteristics - is poured in the mould, which - once the hardening process is finished - is shaken out and deburred. If necessary, a mechanical process is carried out to give anchorages (hooks) the precise required geometry in the coupling with fastening dogs.

It is then so obtained a cast iron sleeper 1 with built in anchorages (hooks) for rail track.

It can be added, that said sleeper 1 can have any section (if anticipated cast anchorages (hooks) are built in).

Moreover, said sleeper 1 can totally be hollow, with different thicknesses, and completely filled up with inert material (for example: sand), in order to dampen vibrations, and so obviously obtaining a lighter cast. The invention shall be better understood following the enclosed drawing, which shows a practical and schematic example of manufacture of the invention itself. Table 1: Figure 1 shows the sleeper 1 front view; Figure 2 shows a sleeper 1 cross section; Figure 3 shows the sleeper 1 upper view. Thickness, shape, length, sections - as shown in the drawing - represent one of the best solutions with respect to the functionality, the optimal shape, and also with respect to the overall weight.

We therefore point out that what described and shown in Table 1 is a practical and schematic example of the invention, since its shapes, dimensions, manufacturing and material details can vary, without forgetting the inspiring and building principle of the invention itself.

Claims

Claims

1) Cast iron sleeper with built in anchorages (hooks) for rail track, characterized by the fact of being made up of a rail sleeper (1), and of anchorages (2); the whole is cast obtained and therefore forming a single piece.

2) According to the previous claim, the sleeper is characterized by the fact of having long term well-defined mechanical characteristics meeting the necessary, constant principles of strength and resistance. 3) According to the previous claims, the sleeper is characterized by the fact of having a seemingly unlimited life.

4) According to the previous claims, the sleeper is characterized by the fact that - thanks to its very homogeneous structure - it optimally distributes stresses. 5) According to the previous claims, the sleeper is characterized by the fact it gives the track a strength suitable to heavy and very fast traffic.

6) According to the previous claims, the sleeper is characterized by the fact that it does not need the arrangement of anchoring plates (2), these being already cast built.

7) According to the previous claims, the sleeper is characterized by the fact that - already at the casting stage - the anticipated gauge is obtained.

8) According to the previous claims, the sleeper is characterized by the fact that anchorages (2) - being manufactured by casting - do not shift, and the gauge is set and fixed.

9) According to the previous claims, the sleeper totally corresponds to what described and shown in the enclosed drawing.