Railway rolling stock – Trucks – Bogie
Reexamination Certificate
1998-07-01
2001-08-14
Avila, Stephen (Department: 3617)
Railway rolling stock
Trucks
Bogie
C105S199200, C191S04500A, C191S050000, C104S117000
Reexamination Certificate
active
06273001
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention refers to the installation of a current collection device on tilting trains. The assembly comprises a pantograph which can move relative to the carbody of the rail vehicle on which it is assembled. The arrangement is such that the pantograph remains unaffected by tilting movements applied to the carbody, and stays practically immobile with respect to the vehicle bogie frame.
SUMMARY OF THE INVENTION
The tendency to shorten ride times in rail transportation has aroused interest in the design of rail vehicles which achieve this aim with no need to build fresh lines for high speed train traffic. This type of train includes the so called tilting trains. A tilting train is a train which uses a built-in device to create an additional superelevation in addition to the cant of the track in curve negotiation. The additional superelevation depends on the running speed and on the characteristics of the curve. This device enables the vehicle to negotiate curves at higher speeds, and also prevents time being lost on deceleration and subsequent acceleration.
Known tilting methods apply a relative rotation between the bogie and the carbody. Electric tilting trains have the additional problem of how to provide for current collection through the pantograph on a vehicle undergoing considerable roll rotations caused by the tilting system. A device must be installed to prevent the pantograph from becoming detached from the overhead catenary by tilting movements.
In recent years a number of types of tilting train have been designed which have solved the problem of electrical current collection connection in a number of ways. The following provides a brief look at the solutions adopted.
a) Pantograph on a non-tilting locomotive. Using this solution, the tilting train consists of a number of tilting passenger cars hauled by a non-tilting locomotive. This locomotive is equipped with the conventional pantograph or pantographs on the roof of the vehicle. The drawbacks to this solution are, firstly, that the drivers of the locomotive undergo extremely high levels of lateral acceleration in comparison to the levels experienced by the passengers, and secondly, the need for a locomotive means that the train consist has quite a number of cars (more than three), or it becomes necessary to haul a non-useful weight if the consist is shorter.
b) Pantograph connected to the bogie structure. This solution is used for electric multiple-unit trainsets, i.e. passenger train units carrying the motor in one or more cars. The pantograph is fitted to the upper section of the vehicle, secured to a structure which is connected to the non-tilting bogie section. This means that the pantograph follows the bogie movements at all times, and remains unaffected by the tilting rotation applied to the carbody of the vehicle. There are a number of drawbacks to this solution. Firstly, the need to set up a structure from the bogie to the roof of the car means reducing useful space in the car, thus reducing passenger space and room for the auxiliary equipments of the train. Secondly, there is a considerable weight increase due to the extra structure which must be fitted for the pantograph. With regard to its advantages, it must be said that fitting a purely mechanical system to secure the pantograph provides the system with a high level of reliability.
c) Pantograph connected to the bogie by means of wire cables. This system keeps the pantograph on approximately the same vertical axis as the bogie, whilst the carbody can tilt below it without exerting an influence on its position. A pantograph using this system is described by the European Patents Office and published as n
Q
485,273. According to the description of the aforementioned patent, the pantograph is placed on a rolling platform on the roof of the car. The platform is connected to the bogie frame by a number of wire cables moving along pulleys in the carbody. The wire cables are tensed by drums on the moving platform. This system has two advantages: a substantial weight reduction and increased useful spaces for the carbody. In this case the entire metal structure for the previous solution is replaced by wire cables fitted around the carbody. Drawbacks of this arrangement include the fact that the wire cable configuration not only transmits the tilting movement to the pantograph, but also all movements of the secondary suspension under normal operation. Such movements, in comparison to tilting movements which are quasi-static, come about when the vehicle is in motion and their frequency content is higher. The entire pantograph system is thus subjected to dynamic and quasi-static demands, thereby reducing the lifespan of the entire system.
This invention consists of an installation for the current collection of electric tilting trains, and comprises a pantograph as in the previous description, connected to the bogie by an arrangement of transmission ropes, the basic aim of which is to remove the system disadvantages mentioned above, so that the pantograph receives only tilting movements and not movements related to the secondary suspension.
Other objectives of this system are simplification of the system and ensuring proper operation of the same.
The invention consists of a pantograph fitted to a platform on the roof of a rail vehicle. This platform can move relative to the roof perpendicularly to the axis of the vehicle. It relates to its bogie by means of a flexible transmission rope which transmits tilting movements of the carbody to the platform. The tilting mechanism consists of a kinematic configuration composed of several swing arms which are installed between the bogie frame and the bogie tilting bolster. In this case, the secondary suspension is located above the bolster. The basic features of this installation, in accordance with the invention, are that the flexible transmission rope or ropes are connected to the bogie at points below the suspension elements, and in this way only tilting movements are passed on to the platform, and those due to secondary suspension are not transmitted. These are provided for in the same way as a non-tilting vehicle, by means of the excess width of the pantograph runner shoe.
According to other characteristics of the invention, flexible transmission rope or ropes of the system consist of a fixed sleeve or sheath and an inner core which moves relative to the sheath. The transmission rope or ropes are connected to the platform on which the pantograph is fitted by means of a mechanism to reduce or increase the movement of the core inside the flexible transmission rope or ropes, whilst they are attached to the bogie by anchoring devices assembled between the bogie bolster and the bogie frame, transmitting only tilting movements between the bogie frame and bolster to the core of the transmission rope or ropes.
The core inside the flexible transmission rope can shift in linear movements with respect to its sheath, and work by traction only or by traction and compression. In the case of the former, at least two transmission ropes shall be required, whilst in the latter case one shall be sufficient. The core inside the transmission rope or ropes may also rotate with respect to the sheath and respond to torque demands in one direction or in both. In the former case, at least two transmission shafts shall be required, whilst in the latter case one shall be sufficient.
In accordance with the invention, the platform shall be assembled on four articulated moving bearing on two straight, coplanar guides, arranged transversely on the vehicle roof, in a symmetric position with respect to the central longitudinal section of the roof, with ascending inclination inwards.
The characteristics set out, in addition to others included in the invention, are provided below in more detail using the sketches attached, showing in diagram format and as non-limitative examples, a way in which they could be constructed.
REFERENCES:
patent: 3712430 (1973-01-01), Charamel
patent: 4471175 (1984-09-01), Gronlund
patent: 5101
Amigot Juan Felix Garcia
Aranzabal Rafael Corta
Benito Asier Jauregi
Loriente Nicolas Moliner
Avila Stephen
Construcciones Auxiliar de Ferrocarriles S.A. CAF
Jules Frantz F.
Ostrolenk Faber Gerb & Soffen, LLP
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