GB2135410A

GB2135410A - Emergency braking mechanism for rail vehicles

Info

Publication number: GB2135410A
Application number: GB08313444A
Authority: GB
Inventors: Ulrich Pistor
Original assignee: Schweizerische Industrie Gesellschaft
Current assignee: Schweizerische Industrie Gesellschaft
Priority date: 1983-02-25
Filing date: 1983-05-16
Publication date: 1984-08-30
Also published as: AU566168B2; CH659624A5; DE3314966A1; GB2135410B; AU1482083A; GB8313444D0

Abstract

The mechanism has a plurality of braking shoes (13, 14) which are lowered onto the rails (4) in emergency braking conditions and are linked with the entire vehicle in such a way that approximately full axle load of the vehicle comes to rest on shoes (13, 14) to generate the braking force. In such braking, the entire vehicle runs onto the braking shoes (e.g. 14) resting on the rails (4) in front of the vehicle wheels (2) in the travel direction, the braking shoes (13, 14) having a run-on surface (23) and a braking surface (24), the shoes being mounted on a frame with bars (10) and cross ties (12) which is caused to fall under its own dead weight. The frame is released to fall down by disengaging a latch (18) by means of a rod, or a cable (21). Cable (21) could be operated or substituted by a withdrawable safety mechanism, such as a pin. <IMAGE>

Description

SPECIFICATION Emergency braking mechanism for rail vehicles The invention relates to an emergency braking mechanism for rail vehicles.

A rail vehicle body such as a carriage or a locomotive, may be hydraulically or pneumatically linked with the undercarriage. In an emergency the body can be lowered by discharging the hydraulic or pneumatic medium with the result that brake skids, loaded by the dead weight of the rail vehicle body, come to rest on the rails. Braking mechanisms for rail vehicles have become known which do not, as is conventional, act on the wheels, but on the rails. See, for example, Swiss patent specification CH PS 176,520.

It is amongst the objects of the invention to provide an improved emergency braking mechanism.

According to the invention there is provided an emergency braking mechanism for a rail vehicle including a plurality of braking shoes capable of being lowered onto the rails and connectable under emergency braking conditions with the entire vehicle so that approximately full axle load of the vehicle comes to rest on the braking shoes and generates the braking force.

DRAWINGS Figure 1 is a side view of a wheel of a rail vehicle with emergency brake shoes and an emergency brake mechsnism in a rest position; Figure 2 is the embodiment according to Figure 1 in front view partly in section; Figure 3 is a view analogous to Figure 1 but after lowering of the braking shoes on a rail track and before wheels of the rail vehicle run on the braking shoes lying ahead of them just prior to emergency braking; Figure 4 is a view analogous to Figure 2, in the position according to Figure 3; and Figure 5 is a view analogous to Figures 1 and 3, during emergency braking.

Referring to the Figures, a section of a rail vehicle 1 is illustrated with one of the wheels 2 as well as its wheel bearing 3. The wheel moves on a rail 4. On a connecting link 5 between the chassis and the brake frame (Figure 2), an L-shaped supporting beam 6 is mounted. On a bar 10 extending parallel lengthwise and outside the rail 4, there is a centrally located bolt 9 and in addition, at each end of the bar 10, there is an axle journal 11 for swingably mounting the braking shoes 13 and 14 respectively. Two bars 10 are arranged laterally lengthwise on each side of the vehicle outside the wheels 2 at a small distance (guide surface 8/wheel 2) of a few millimeters (e.g. 5 mm). The respective bars 10 are transversely connected by cross ties 1 2 so that the whole forms a frame.With each braking shoe 13 and 14 is associated a limit bolt 15, the purpose of which is to insure that the braking shoes 1 3 and 14 in the rest position assume the position shown in Figure 1. On a swivel bolt 1 7 mounted on the supporting L-beam 6, is mounted a latch 1 8 provided with a notch 1 9 for swinging movement. Within the area of these notches 19 there is connected a cable 21, which can also be a rod, which permits the latch 1 8 to be swung around the bolt 1 7 for example from the driver's cabin (not shown). The braking shoes 13 and 14 have each an inclined run-on surface 23 as well as a braking surface 24.They are additionally provided with a lateral control element in the form of a lateral guide ridge 25 in order to guide the rail vehicle in case of emergency braking which would not otherwise be assured when the wheel 2 has run up the inclined surface 23. The braking shoes 13 and 14 are provided with a front chamfer 26 in order to prevent unnecessary shocks or fractures in case of non-level rail joints.

The above described emergency braking mechanism can be activated independently of extraneous means such as electric power, fuels, etc., by pulling the cable 21. This causes the latch 18, which holds back the bolt 9 of the bar 10 in its notch 19, to swivel clockwise around the bolt 1 7 whereupon the entire frame with the bars 10 and the braking shoes 1 3 and 14 falls on the rail 4 under its dead weight. This causes, as shown, the braking shoes 13 and 14 to swing around their axle journals 11 and to rest with their braking surfaces 24 on the rail 4. They hereby bring about a braking of the parts connected with the shoes, whereby the linkage between the vehicle body (not shown) and the wheels 2 is such that the wheels 2 in this travel direction run onto the braking shoes in front of them. The.vehicle is braked via the braking surface 24.The total weight of the rail vehicle including the wheel sets, wheel set drives, and the vehicle body is effectively utilized by means of the run-on surfaces 23 on which the rail vehicle rest depending on the travel direction, and thus on the braking surfaces 24 of the braking shoes 13 and 14. In this manner a braking force corresponding to the total weight of the rail vehicle is achieved. It is possible therefore to achieve an optimum braking weight and, all other conditions being equal, an optimum braking effect. The cable 21 could be operated or substituted by a withdrawable safety mechanism such as a pin.

In order to release the emergency braking mechanism, the rail vehicle is moved back from the braking shoe resting in front of it so that it reaches the position according to Figure 3.

Therefore with the aid of a crowbar, for example, the frame with the bars 10 is lifted and the bolts 9 are locked in the notches 1 9 of the latches 1 8 which have to be retracted. In this way the emergency braking mechanism according to Figure 1 and 2 is restored again to its original resting position.

This design of an emergency braking mechanism has the advantage that the weight of an entire rail vehicle including wheel sets, axles, and the drives is utilized for generating a braking force without using any additional externally generated energy. It requires no hydraulic mechanism and therefore the rails are not soiled with oil with the attendant reduction in the coefficients of friction. The normal braking operations during driving are in no way affected or impaired by this emergency braking mechanism.

As it is mechanical and extremely simple, this emergency braking system requires practically no -maintenance. The free suspension and the movements resulting from the dead weights, and in particular those of the laterally guided frame 10, 12, are safe. The entire emergency braking system has no effect on the other parts of the locomotive and/or other rail vehicles, so that this emergency braking system can be additionally installed on an arbitrary already existing rail vehicle, such as a tram, carriage or a locomotive.

Claims

1. An amergency braking mechanism for a rail vehicle including a plurality of braking shoes capable of being lowered onto the rails and connectable under emergency braking conditions with the entire vehicle so that approximately full axle load of the vehicle comes to rest on the braking shoes and generates the braking force.

2. A mechanism according to claim 1 in which the braking shoes are adapted for resting on the rails for the entire vehicle to run onto the shoes in front of the vehicle wheels in the travel direction under emergency braking conditions.

3. A mechanism according to claim 1 or claim 2 in which the braking shoes are swingably mounted on a bar capable of being lowered by its own dead weight and are provided with a chamfer at the front as well as with lateral guide ridge for engaging the rails.

4. A mechanism according to any of the preceding claims in which means are provided for releasing the mechanism from a support to permit it to fall down for emergency braking.

5. A mechanism according to any preceding claim in which the braking shoes have inclined run-on surfaces for vehicle wheels in order to support the entire vehicle.

6. A mechanism according to any of the preceding claims in which cross ties form a frame for laterally enclosing the wheels on each side of the vehicle so that the frame with the braking shoes is located for lowering to the emergency braking positions.

7. An emergency braking mechanism substantially as described with reference to and as shown in the Figures.

8. A rail vehicle having an emergency braking mechanism according to any of the preceding claims.