EP0541961A2

EP0541961A2 - Railroad switch structure

Info

Publication number: EP0541961A2
Application number: EP92117257A
Authority: EP
Inventors: Antonio Di Teodoro
Original assignee: Omse Officine Meccaniche Sant'emilio SpA
Current assignee: Omse Officine Meccaniche Sant'emilio SpA
Priority date: 1991-10-14
Filing date: 1992-10-09
Publication date: 1993-05-19
Also published as: EP0541961A3; IT221948Z2; ITMI910886V0; ITMI910886U1

Abstract

The railroad switch structure (1) comprises at least one wide-V rail (2) at a frog which is provided with at least one point (3) and is constituted by means of mutually assembled parts; the wide-V rail (2) has, proximate to the frog, a raised region (4) whose upper surface (5) for the rolling of the railroad wheels (6) is higher than the corresponding upper surface (7) of at least one point (3).

Description

The present invention relates to a railroad switch structure.
As is known, current railroad switches comprise a wide-V rail at the frog, which can be simple and/or double.
Current frogs constituted by parts assembled mutually or by means of mechanical couplings have a wide-V rail whose upper surface, for the rolling and resting of the railroad wheels, is at the same level as the point of the frog.
In view of the above, it can be easily understood that railroad wheels, during their transfer from the surface of the wide-V rail to the surface of the point, transfer their static load and the related dynamic increase substantially instantaneously from the wide-V rail to the point.
Initially, in view of the ratio between the transverse cross-section of the wide-V rail and the cross-section of the point, most of the static and dynamic loads bears on the wide-V rail and only a little bears on the point, which however begins to be subject to a flattening which tends to worsen as time goes by.
Bearing in mind that the railroad wheels of a train are rigidly coupled together by means of a rigid axle, due to the above mentioned point flattening, every time one railroad wheel leaves the wide-V rail it actually falls, together with the axle which supports it, with consequent blows to the structure of the frog and rapid degradation of the geometry of the unit.
The above entails the need for maintenance interventions which consist of the restoring, by means of the application of metal with an electric arc, of the integrity of the point and, subsequently, in a general take-up of the longitudinal and transverse level of the entire device by means of vibratory tamping machines.
Bearing in mind that maintenance interventions of the above described type are performed on the average every 12-16 months (for lines with approximately 15-20,000 t/day of traffic), it is immediately understood that switch frog maintenance is extremely onerous, especially in view of the fact that their technical life can be assumed to be approximately twenty years.
The aim of the present invention is to solve the problems of the known art.
Within the scope of this aim, an important object of the invention is to provide a railroad switch structure which reduces mechanical and flattening stresses upon the transit of railroad wheels at the point of the frog.
Another object of the present invention is to provide a railroad switch structure which considerably increases the life of the point of the frog.
A further object of the present invention is to provide a railroad switch structure which reduces the frequency of maintenance interventions with application of metal with an electric arc to restore the original shape of the point.
Not least object of the invention is to provide a railroad switch structure which can be applied to existing railroad lines equipped with frogs made with parts which are mutually assembled by means of mechanical couplings.
This aim, these objects and others are achieved by a switch structure which comprises at least one wide-V rail at a frog provided with at least one point and constituted by means of mutually assembled parts, characterized in that said at least one wide-V rail has, proximate to said frog, a raised region whose upper surface, for the rolling of the railroad wheels, is higher than the corresponding upper surface of said at least one point.
Further characteristics and advantages will become apparent from the detailed description of a railroad switch structure according to the invention, illustrated only by way of non-limitative example in the accompanying drawings, wherein:

Figure 1 is a schematic plan view of a wide-V rail executed according to the invention, arranged at a frog equipped with a point;
Figure 2 is a sectional view, taken along the plane II-II of Figure 1 according to the invention, which shows the resting of a railroad wheel on the raised surface of the wide-V rail;
Figure 3 is a sectional view, taken along the plane III-III of Figure 1 according to the invention; and
Figure 4 is a sectional view, taken along the plane IV-IV of Figure 1 according to the invention.

With reference to the above figures, the railroad switch structure according to the invention, generally designated by the reference numeral 1, comprises at least one wide-V rail and more precisely two wide-V rails, generally designated by the reference numeral 2, at a frog which is equipped, in the case illustrated in the drawings, with a point 3 and is constituted by mutually assembled parts.
Advantageously, each wide-V rail has, proximate to the frog, a raised region 4 whose upper surface 5, for the rolling and resting of the railroad wheels (only one of which, designated by the reference numeral 6, is shown in the figures), is higher than the corresponding upper surface 7 of the point 3.
The raised region 4 has an entry ramp 8 and an exit ramp 9 which have the same grade.
In particular, the raised region, illustrated with oblique shading in Figure 1, has at least one terminal portion which is arranged to the side of the point 3; the exit ramp 9 is furthermore arranged to the side of said point.
The length of the raised region and the grade of the entry and exit ramps are furthermore directly proportional to the point switching angle.
Furthermore, advantageously, the upper surface 5 of the wide-V rail has a profile which is complementary to the profile of the railroad wheels.
It should be furthermore specified that the raised region 4 and the ramps 8 and 9 are defined by the mechanical machining of a conventional rail whose head is higher than normal or can be defined by the cambering of the wide-V rail, which in this case is supported downward by supports, not illustrated in the drawings, which have a greater-than-normal thickness.
It should furthermore be noted that railroad switches according to the present invention can be provided not only by purely mechanical assembly of the parts but also by totally and/or partially welded assembly, using, for the individual components, elements which are not obtained from normal or larger-than-normal rail profiles but from elements obtained from forged, pressed, cast and laminated parts with any profile.
The operation of the railroad switch structure according to the invention is evident from what has been described and illustrated.
In particular, with reference to Figures 1, 2 and 3, it can be easily seen that the lifting of the wide-V rail allows the railroad wheels to rise along the entry ramp 8 and then gently descend along the exit ramp 9 at the point 3.
In this case, the railroad wheels advantageously do not use the end or the initial part of the point 3, which has a reduced cross-section, as resting surface, but rest on the part of the point whose cross-section is sufficient to withstand the flattening stresses, thus avoiding this problem.
For example, in Figure 2 it can be clearly seen that a railroad wheel 6 which is about to leave the wide-V rail 2 to rest on the upper surface 7 of the point 3 still has a distance H from said point.
Subsequently, said wheel, as can be seen in Figure 3, rests on the surface of the point in a region which has a larger-than-normal cross-section and is thus less affected by flattening stresses.
In practice it has been observed that the switch structure according to the invention is particularly advantageous in that it enormously limits maintenance interventions suitable to restore the original shape of the flattened point, with the consequence of a considerable saving of labor and materials during the technical life of the frogs of switches.
In practice, the materials employed, as well as the dimensions, may be any according to the requirements and the state of the art.
Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly such reference signs do not have any limiting effect on the scope of each element identified by way of example by such reference signs.

Claims

Railroad switch structure (1) comprising at least one wide-V rail (2) at a frog which is provided with at least one point (3) and is constituted by means of mutually assembled parts, characterized in that said at least one wide-V rail (2) has, proximate to said frog, a raised region (4) whose upper surface (5), for the rolling of railroad wheels (6), is higher than the corresponding upper surface (7) of said at least one point (3).
Structure according to claim 1, characterized in that said raised region (4) has an entry ramp (8) and an exit ramp (9), said exit ramp being arranged to the side of said at least one point (3).
Structure according to claim 1, characterized in that said raised region (4) has at least one terminal portion which is located to the side of said at least one point (3).
Structure according to claims 1 and 2, characterized in that said raised region (4) and said ramps (8, 9) are defined by the mechanical machining of a rail whose head has a larger-than-normal height.
Structure according to claim 2, characterized in that said ramps (8, 9) have the same grade.
Structure according to claim 1, characterized in that said raised region is arranged symmetrically with respect to the kink of said frog.
Structure according to claims 1 and 2, characterized in that the length of said raised region (4) and the grade of said ramps (8, 9) are directly proportional to the switching angle of said at least one point (3).
Structure according to claim 1, characterized in that said upper surface (5) of said frog has a profile which is complementary to the profile of said railroad wheels (6).
Structure according to claim 1, characterized in that said point (3) has said upper surface (7), for the rolling of said railroad wheels (6), spaced from its end.
Structure according to claim 1, characterized in that said raised region (5) is defined by the cambering of said wide-V rail, which is supported below by thicker-than-normal supports.