EP2333153A1 - Fastening device for a stock rail to a railway switch - Google Patents

Abstract

The device (7) has a conical thrust bushing (7') inserted into a corresponding conical bore (7'') of a stock rail (5) and welded on an assembly of rails. A switch point and a stock rail assembly block are provided at a middle part of an internal weld (8) at the conical thrust bushing. The conical thrust bushing is leveled on an internal support face (5') of the stock rail against the assembly of rails.

Description

DESCRIPTION

The present invention relates to the field of railway infrastructure, in particular track materials, in particular tramway, and relates to a device for fixing a counter-needle rail to a switchgear, such as a block of semi-switching consisting of an assembly of rails and other profiles.

Point switches and turnouts, in particular used in the field of tram track equipment infrastructure, which are subject to less stress than those to which railway track apparatus is subject, They are generally made in the form of mechanically welded assemblies which, admittedly, have lower performances, but which have a much lower cost price.

Currently, the attachment of a counter-needle rail to such a switchgear, consisting of an assembly of rails and other mechanically welded profiles, is generally performed by welding said counter-needle rail on said assembly.

Such a counter-needle rail welding, which is made of a heat treated steel grade, is difficult to perform directly on the other components of the rail assembly and other welded sections.

Indeed, traditionally, the rail is preheated in the vicinity of the zone to be welded, at a temperature of the order of 300 ° C. to 350 ° C., followed by rapid welding followed by very slow cooling. of the assembly thus obtained.

Such a welding method has a number of disadvantages, namely, firstly, that the initial preheating of the counter-needle rail is long and difficult to perform, the reference temperature must not be exceeded and all locations solder must be heated at the same time and, secondly, that during preheating, the rail is deformed and must deploy many devices that must be maintained by a third person. In addition, the preheating can practically be achieved with the aid of a torch, which is dangerous for the third person assisting the operator performing the welding.

In addition, after welding and complete cooling of the assembly obtained, it is generally confronted with large amplitude deformations which must imperatively be corrected by pressing the press. Finally, all the operations described above require a large expenditure of energy, as well as a large number of ancillary hours of preparation and others, which are not productive, so that the cost of production is heavily burdened, while the The welding operation itself is of relatively short duration.

To obviate these disadvantages, a solution has been sought to avoid welding the steel of the counter-needle rail on the rail assembly and other profiles of the switchgear and thus to prevent the preheating of the together.

For this purpose, we know in particular by WO 00/65154 a device for fixing the counter-needle rail using metal rings provided with a flange and through corresponding holes in the web of the counter-needle rail. These metal rings have a length between their free end and the flank of the flange less than the thickness of the web of the counter-needle rail, so that their free end extends away from the welded components of the switchgear. These metal rings are welded by a plug-type weld, at their free ends on said mechanically welded components of the switchgear.

As a result, during the cooling of the weld, the removal of the latter has the effect of pulling the end of each ring towards the mechanically welded components of the switchgear, so that the collar of each ring is applied. by force, and therefore clamped on the corresponding face of the counter-needle rail, and thus performs a clamping of said counter-needle rail on the mechano-welded assembly. The assembly thus obtained is as rigid as if the weld was made directly in the bore of the web of the counter-needle rail, without cooperation with the metal collar ring.

As a result, the assembly obtained according to this document WO 00/65154 does not present any flexibility and the stresses applied in the case of lateral forces are transmitted directly to the weld closest to the point of application of the corresponding load, which can cause fatigue failure at said weld.

We also know, by DE-C-552,276 , a device for fixing a counter-needle rail to a switchgear, in which is implemented a conical bearing ring inserted in a corresponding hole of the counter-needle rail, this conical bearing ring being welded externally on a spacer. In such an assembly the withdrawal of the weld, during its cooling, results in a corresponding displacement of the conical bearing ring in its bore, so that the force-fitting thereof on the spacer, even with a perfectly defined prestressing can not be guaranteed and that obtaining a flexibility contributing to the resistance to fatigue under lateral load is not possible.

Indeed, in this document DE-C-552,276 , the rings are welded on the end of the cross members, by their outer face, so that during the removal of the weld bead after welding, said rings tend to be spaced from the rails against which they are tightened before welding.

The object of the present invention is to overcome these drawbacks by proposing a device for fixing a counter-needle rail to a switchgear, such as a half-switch block composed of a rail assembly allowing a certain flexibility in the assembly of the counter-needle rail on the mechanically welded assembly and thus a better resistance to fatigue under lateral load.

For this purpose, the device for fixing a counter-needle rail to a switchgear, such as a half-switch block consisting of a rail assembly and other profiles, is characterized in that it consists of less a conical bearing ring forcibly inserted into a conical bore corresponds to the counter-needle rail and welded to the profile assembly.

The invention will be better understood, thanks to the following description, which relates to a preferred embodiment, given by way of non-limiting example, and explained with reference to the attached schematic drawing, the single figure of which is a view in section of the device according to the invention.

The figure of the appended drawing represents, by way of example, a half-switch unit of a switchgear consisting of a needle 1 mounted on a sliding plate 2, said sliding plate 2 being itself mounted on a reinforcement vertical 3 and on a needle cover 4, the needle assembly 1, sliding plate 2, vertical reinforcement 3 and needle cover 4 being welded to a base plate 6. On this half-switching block is fixed, by means of a fastening device 7 , a counter-needle rail 5.

According to the invention, the fastening device 7 of the counter-needle rail 5 on the switch unit half-switch block consists of at least one conical bearing ring 7 'forcibly inserted in a conical bore corresponding to 7 " of the counter-needle rail 5 and welded to the profile assembly forming the half-switching block, via a weld 8 internal to the conical bearing ring 7.

The invention will be described only in connection with a single fastening device 7, but, of course, several identical devices 7 are used to achieve the fixing of a counter-needle rail.

According to a characteristic of the invention, each conical bearing ring 7 'is force-fitted into the corresponding conical bore 7 ", by irreversible clamping and is leveled at the inner face 5' of support of the counter rail. needle 5 against the assembly of sections forming the half-switch block of a switchgear.

The irreversible tightening of the conical bearing ring 7 'in the corresponding conical bore 7 "is obtained by predicting a taper angle of the bore 7" and the corresponding surface of the ring 7', whose determination is within reach of the skilled person and does not require any further explanation. In fact the angle of conicity must be provided such that the conical bearing ring 7 "can be pressed into the corresponding bore 7" so that it is permanently maintained during all the preparatory phases for the final assembly of the counter Needle with the other components of the half-turn block of the switchgear. Also known, the assembly of the conical bearing ring 7 'to the counter-needle rail 5 is performed by means of a press and the clamping obtained requires no implementation of additional holding means.

The operation of shaving the end of the conical ring 7 'at the level of the face of the counter-needle rail 5 against the assembly of profiles forming the half-switch block of a switchgear is carried out after the clamping, irreversible and therefore definitive of said ring 7 'in the corresponding bore 7 "It is thus possible, during the operation of setting up the weld 8 inside the conical bearing ring 7', to perform the welding avoiding any contact with the constituent metal of the counter-needle rail 5, no clearance existing between the end of said conical bearing ring 7 'and the bearing surface of the counter-needle rail 5 against the assembly rail forming the half-switch block of the switchgear.

Because of this embodiment, two very important advantages are obtained, namely, on the one hand, that the counter-needle rail 5 is not preheated for the welding operation and, on the other hand, that the heat shrinkage of the weld 8 does not cause a clamping effect of the counter-needle rail 5 against the rail assembly. As a result, the fastener according to the invention makes an assembly with a perfect contact, without play, but also without any unnecessary clamping effect of said counter-needle rail 5 against the assembly of profiles, so that such an assembly is more durable than existing assemblies to date.

Indeed, the bending of the web of the counter-needle rail 5 occurring during the application of a lateral force, instead of directly urging the weld 8 in its upper part, as is the case with existing solutions to date, will have the effect of sliding work the upper zone of the conical bearing ring connection 7 '/ corresponding conical drilling 7 ", creating a longitudinal deformation of the counter-needle rail 5. Thus, the lateral force will be distributed on the neighboring rings 7 '(upstream and downstream), so that the stresses at the welds are greatly reduced and the fatigue strength will be improved accordingly.

Thanks to the invention, it is possible to achieve a fastening of a counter-needle rail on a half-switch block of a switchgear by implementing an assembly of less rigidity than that of the solutions. to date, so that the performance of the whole of the switchgear is improved, and in particular the resistance to the fatigue test under lateral load.

Of course, the invention is not limited to the embodiment described and shown in the accompanying drawing. Modifications are possible, particularly from the point of view of the constitution of the various elements or by substitution of technical equivalents, without departing from the scope of protection of the invention.

Claims (2)

Device (7) for fixing a counter-needle rail to a switchgear, such as a half-switch block composed of a rail assembly and other sections, characterized in that it consists of at least one ring with conical support (7 ') forcibly inserted in a corresponding conical bore (7 ") of the counter-needle rail (5) and welded to the rail assembly forming the half-switch block, via a welding (8) internal to the conical bearing ring (7). Device according to claim 1, characterized in that each conical bearing ring (7 ') is force-fitted into the corresponding conical bore (7 ") by irreversible clamping and is leveled at the inner face (5). ') support the counter-needle rail (5) against the rail assembly forming the unit switch half-switch block.

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