EP0799144A1

EP0799144A1 - Rail vehicle brake device

Info

Publication number: EP0799144A1
Application number: EP95942749A
Authority: EP
Inventors: Jean-Michel Deramaux; Bernard Caron
Original assignee: Forges De Fresnes Ste
Current assignee: Forges De Fresnes Ste
Priority date: 1994-12-22
Filing date: 1995-12-15
Publication date: 1997-10-08
Anticipated expiration: 2015-12-15
Also published as: HUT76962A; RO117247B1; SK81697A3; CZ192997A3; FR2729357A1; ATE200765T1; PL320885A1; US6138800A; DE69520799D1; WO1996019372A1; RU2162805C2; DE69520799T2; EP0799144B1; PL179343B1; ES2159327T3; HU218775B

Abstract

A rail vehicle brake device including drive means (1, 2) for applying a brake pad onto a braking surface secured to a vehicle wheel. The device includes a reaction member (11, 20), at least one lever (6; 6', 6"; 33, 33') engageable therewith, and connecting means (23, 41) between the drive means and the lever, said brake pad being supported by the lever in such a way that it can be applied onto said braking surface by pivoting the lever by means of said drive means and said reaction member.

Description

BRAKING DEVICE

FOR RAIL VEHICLE

The present invention relates to a braking device for a railway vehicle, and more particularly to such a device comprising traction means arranged to apply a braking pad on a braking surface secured to a wheel of the vehicle.

Such devices are already known, which are more particularly used on freight wagons. The brake shoe acts by friction on the tire of the wheel to cause braking. The traction means generally consist of a triangular member made of metal bars and called the brake triangle. This triangle is isosceles with its vertex in the plane of symmetry of the wagon and its two other angles in the vicinity of two of the wheels of the wagon mounted on the same axis.

The braking force is applied to the top of the brake triangle in the aforementioned plane of symmetry, and this force is equally distributed between the two pads to apply them to the corresponding wheel tread to cause the braking of the wagon.

Also known, generally used on power cars and passenger cars, disc brakes of the same type as those used for example on motor vehicles. These brakes have the advantage of providing very vigorous braking, and of being quieter and generating less vibration than traditional brakes acting on wheel treads. However, they are very expensive and work in a completely different way. They are therefore not adaptable to railway vehicles fitted with brake triangles.

The present invention aims to provide improved braking means for railway vehicles. More particularly, it aims to provide a braking device combining the simplicity and robustness of traditional brakes with more effective braking. It also aims to provide such a device which can use the traditional brake chain triangle brake. It further aims to increase the braking capacity of such braking chains without increasing the braking force applied to the brake triangle. To this end, the subject of the invention is a braking device for a rail vehicle, comprising traction means arranged to apply a braking pad on a braking surface secured to a wheel of the vehicle, characterized in that it comprises a reaction member, at least one lever arranged to cooperate with said reaction member, connection means between said traction means and said lever, said brake shoe being carried by said lever to be applied to said braking surface by pivoting of said lever under the action of said traction means and said reaction member.

The lever device according to the invention makes it possible to increase the braking power while retaining the same braking control chain as in conventional devices.

In a particular embodiment of the invention, said reaction member is constituted by the tire of a vehicle wheel, said lever cooperating with said tire by means of a support member

More particularly, said support member can form a braking pad, said braking surface then forming an additional braking surface

The additional braking surface makes it possible to increase the braking capacity compared to a conventional triangle braking device. However, as indicated above, the braking control chain is the same as in these conventional devices.

As a variant, the support member does not participate in braking and consists, for example, of a roller rolling on the tire

In another embodiment of the invention, the reaction member is integral with the structure of the vehicle. Of course, in the case where the vehicle is a bogie vehicle, the reaction member is in fact integral with the structure of the bogie.

This embodiment makes it possible to avoid involving the tire of the wheel in the braking process, and consequently to avoid damaging it. This results in a reduction in noise and vibrations.

Also in a particular embodiment of the invention, said lever comprises two lever arms on either side of its pivot axis, one lever arms carrying the support member and the other lever arm carrying the brake shoe.

More particularly, said braking surface may be a cylindrical surface coaxial with the wheel.

Said braking surface can also be a flat annular surface substantially parallel to the plane of the wheel and coaxial with the wheel.

In the latter case in particular, the device according to the invention may comprise two integral braking surfaces, each associated with a pad and a lever, the two pads exerting their forces in opposite directions on their respective braking surface.

It is thus possible to globally increase the braking force, and therefore the braking capacity of the device, without increasing the force exerted on the traction means. In fact, the forces exerted on the braking surfaces will generally be exerted laterally and will compensate each other.

According to the particular embodiment described above, the device according to the invention may comprise two pad-carrying levers and an operating lever, one of said pad-holding levers being mounted at its end opposite the pad, pivoting on the reaction member, said operating lever also being pivotally mounted on the reaction member and being connected to the traction means, the other shoe-carrying lever having its end opposite the shoe connected to the operating lever, and said door levers -patin being connected in their central area by a connecting rod.

A few embodiments of the invention will now be described, by way of non-limiting example, with reference to the appended schematic drawings in which:

- Figure 1 illustrates a first embodiment of the invention;

- Figure 2 illustrates a second embodiment of the invention;

- Figure 3 is a partial top view of a third embodiment of the invention;

- Figure 4 is a front view;

- Figures 5 and 6 are perspective views of one of the levers of Figures 3 and 4; - Figure 7 is a top view of a fourth embodiment of the invention; and

FIGS. 8 and 9 are perspective views of two of the members of the device in FIG. 7.

We see in Figure 1 a brake triangle of known type, formed by two metal bars 1 of the same length and a third bar 2. A jack not shown allows to exercise at point 3 common to the two bars 1 an illustrated effort by arrow F.

The points 4 common on the one hand to the bar 2 and on the other hand to each of the bars 1 respectively, are located in the vicinity of each of the wheels 5 carried by the same vehicle wheel shaft. When the tensile force F is exerted at point 3, points 4 approach the wheels 5.

The points 4 are in fact hinge axes for levers 6 each comprising two lever arms 7 and 8 respectively, at right angles. The lever arms 7 are substantially parallel to the axes of the wheels 5, while the arms 8 are substantially parallel to the axis of the vehicle.

The lever arms 7 carry, at their end opposite to the articulation 4, a brake shoe 9 by means of a shoe holder (not shown). Likewise, the arms 8 carry, at their end opposite to the articulation 4, a shoe 10. The shoes are produced in a known manner from cast iron and the shoes 10 from composite friction material.

When traction is exerted on the brake triangle, the pads 9 come, in known manner, into contact with the tires 11 of the wheels 5, which has the effect of providing a first braking force. By reaction, the levers 6 pivot in the direction of the arrows F1. In this movement, each shoe 10 comes into contact with an annular friction strip 11 situated in a plane parallel to the plane of the wheel, which has the effect of providing a second braking force.

The annular bands 12 are made of any suitable friction material. They are coaxial with the wheels 5 to which they are fixed and of which they are therefore integral in rotation.

It can therefore be seen that, for the same tensile force F as in the devices of the prior art, the invention makes it possible to apply a first braking force of F / 2 to the wheel treads and in addition a second force of braking on the bands 12. The two braking forces exerted on the two bands 12 are directed outwards and therefore opposite, which ensures the balance of the brake triangle.

In the embodiment of FIG. 2, the lever arm opposite the lever arm 7, namely the lever arm 8 ′, carries a pad 10 ′ which cooperates with a complementary braking surface 12 ′ cylindrical, coaxial with the wheel 5. As before, the tire 11 exerts on the shoe 9 a reaction force tending to pivot the lever 6 around the joint 4 in the direction of the arrow F1. The pad 10 'is therefore applied against the surface 12', which, here too, provides a second braking force

The embodiment of Figures 3 to 6 differs from that of Figure 1 essentially in that it comprises two levers 6 'and 6 "mounted on joints 4' and 4". These articulations are here carried on a part 19 mounted at the end of the bars 1 and 2 and consist of yokes 20 mounted on the axes 4 'and 4 ". The pad holders 21 are mounted on the lever arms 8' and 8 "and support the friction pads 10a and 10b themselves.

The lever arms T and 7 "here carry at their end protrusions in return 21 'and 21" together receiving an axis 22 horizontal and parallel to the axis of the wheels, and supporting the shoe holder 9'. The axis 22 therefore connects the ends of the lever arms 7 ′ and 7 ″ and the shoe holder 9 ′.

The wheel 5 here carries two complementary friction surfaces on which act two pads 10a and 10b. It thus acts as the disc of known disc brakes.

When traction is exerted on the brake triangle, the pad 9 is pressed on the tire 11 which pushes the axis 22 and rotates the levers 6 'and 6 "around the axes 4' and 4" so that the pads 10a and 10b are applied to the additional braking bands.

In the embodiment of FIGS. 7 to 9, the reaction member is a fixed member 20, integral with the supporting structure of the wheels, and therefore either of the body of the wagon or of the structure of the bogie. This member 20 supports two fixing lugs 21 and 22, the function of which will be seen below.

An operating lever 23 in the form of a square is pivotally mounted at its midpoint on the ear 21, about an axis 24. The end of one of its branches, 25, forms a yoke 26 and the end of its other branch 27 has a bore 28.

The ends of ba es 1 and 2 support a fitting 29 in which an oblong orifice 30 is formed An axis 31 passes through the holes 32 of the yoke 26 and the orifice 30

Two levers 33 and 33 'have one of their ends which supports a brake shoe 34 and 34' respectively cooperating with braking surfaces 35 and 35 'formed on the flanks of the wheel 36 Alternatively, the surfaces 35 and 35' could be formed on a disc mounted fixed on the axis of the wheel 36.

A connecting rod 37 connects the end of the branch 27 of the bracket 23 to the end of the lever 33 opposite the shoe 34. For this purpose, this connecting rod is articulated at one of its ends on an axis 38 passing through the hole 28 and at its other end on a pin 39 mounted on the aforementioned end of the lever 33, opposite the shoe 34

The lever 33 'at its end opposite to the shoe 34' articulated on the ear 22 of the fixed member 20 The middle zones of the levers 33 and 33 'are connected by connecting rods 41 fixed to axes 42 and 42' respectively .

When traction is exerted on the brake triangle, it causes the bracket 23 to pivot in the direction of the arrow F2. This in turn brings the lever

33 to pivot in the direction of arrow F3 around the axis 42. This results on the one hand in pressing the pad 34 on the braking surface 35 and, on the other hand, a traction exerted by the link 41 on lever 33 'in the direction of arrow F4 Thus, the two pads

34 and 34 'are applied to their respective braking surface 35 and 35' Consequently, in this embodiment, the tire 43 of the wheel 36 is not stressed.

Claims

1- Braking device for a railway vehicle, comprising traction means (1, 2) arranged to apply a braking pad on a braking surface secured to a wheel of the vehicle, characterized in that it comprises a reaction (11, 20), at least one lever (6; 6 ', 6 "; 33, 33") arranged to cooperate with said reaction member, connecting means (23, 41) between said traction means and said lever, said brake shoe being carried by said lever to be applied to said braking surface by pivoting of said lever under the action of said traction means and said reaction member.

2- braking device according to claim 1, wherein said reaction member is constituted by the tire (11) of a vehicle wheel, said lever cooperating with said tire by means of a support member (9 ).

3- A braking device according to claim 2, wherein said support member forms a braking sole, said braking surface forming a complementary braking surface.

4- Braking device according to any one of claims 2 and 3, wherein said lever comprises two lever arms (7,8) on either side of its pivot axis (4), one of the arms lever carrying the support member and the other lever arm carrying the braking member

5- braking device according to claim 1, wherein the reaction member (20) is integral with the vehicle structure.

6- Braking device according to any one of claims 1 to 5, wherein said braking surface is a cylindrical surface (12 ') coaxial with the wheel.

7- Braking device according to any one of claims 1 to 5, wherein said braking surface is an annular surface (12) plane substantially parallel to the plane of the wheel and coaxial with the wheel.

8- Braking device according to claim 7, comprising two complementary braking surfaces integral, each associated with a shoe and a lever, the two shoes exerting their forces in opposite directions on their respective braking surface. 9- Braking device according to all of claims 5 and 8, comprising two pad-carrying levers (33, 33 ') and an operating lever (23), one of said pad-holding levers being mounted at its opposite end on the shoe, pivoting on the reaction member (20), said operating lever also being pivotally mounted on the reaction member and being connected to the traction means, the other shoe-carrying lever having its end opposite the shoe connected to the operating lever, and said pad-carrying levers being connected in their central zone by a connecting rod (41).