Railway Bogies

Abstract

This invention relates to a bogie (10), including a load bearing point (11), a wheel set portion (12) and an intervening spring suspension (13). A load weigh valve (15) is fixed between the load portion (11) and the spring (16) of the suspension (13). The valve (15) is mounted within a wedge element (19) so that it continually measures the vertical load.

Description

This invention relates to railway bogies.

In existing railway bogies it is known to provide load weigh valves sitting atop suspension springs, such that they are positioned between the sprung mass of the bogie and wagon and the unsprung mass of the wheel set. The load weigh valve is held in a fixed location on the bogie frame, whilst the sprung mass generally moves vertically upwards and downwards in a fixed vertical z-plane. In this configuration the load weigh valve measures a proportion of the sprung mass via the spring force, which is a constant for a given load. However any vertical misalignment or horizontal relative movement in the X and Y planes between the unsprung mass and the sprung mass, for example, as a result of wheel set steering, can lead to inaccuracy in the resulting absolute amount of braking load, which is applied proportionally to the output of the load weigh valve.

From one aspect the invention consists in a wheel set, a suspension for supporting the load on the wheel set, the suspension including at least one spring mounted on the wheel set, a wedge element for location between the load and spring to accommodate changes in vertical alignment between the load and wheel set and a load weigh valve for providing an indication of the mass of the load as applied to the spring characterised in that the load weigh valve is mounted between the spring and the wedge element.

As the load weigh valve is now not fixed in vertical alignment, but moves with the wedge element, for example when the bogie steers in the X and Y planes, with the frame, the errors provided by the previous system either do not arise or are substantially mitigated.

Preferably the load weigh valve is mounted on the wedge element for movement therewith and conveniently the wedge element may define a chamber, for example the wedge element may be hollow, and the load weigh valve may be mounted therein.

The invention also includes a railway vehicle having at least two bogies as defined above and wherein one bogie has at least a forward inclined wedge element and the other bogie has at least a rearward inclined wedge element and the load weigh valves may be respectively on the forward and rearward inclined elements.

A vehicle may further include a computing device for computing a mean indication from the respective indications of the load valves. In this case it may additionally include a controllable braking system responsive to the mean indication.

Although the invention has been defined above it is to be understood it includes any inventive combination of the features set out above or in the following description.

The invention may be performed in various ways and an embodiment will be described, by way of example, with reference to the accompanying drawings in which

FIG. 1 is a cross-sectional view through part of one end of a bogie of a prior art arrangement; and

FIG. 2 is an equivalent view of an embodiment of the invention; and

FIG. 3 is a schematic view of part of a railway vehicle having two bogies.

FIG. 1 illustrates a known bogie suspension arrangement. The bogie, part of which is shown at 10, includes a load bearing portion 11, a wheel set portion 12 and intervening spring suspension 13. The load portion 11 and wheel set portion 12 are designed to move vertically with respect to one another, this movement being defined by inter-engaging faces, which are generally indicated at 14.

A load weigh valve 15 is fixed between the load portion 11 and a spring 16 of the suspension 13 by means of plates 17 and 18 and at the interface 17a, by means of screw fastenings.

As previously indicated this arrangement works well when there is true vertical movement, but the spring 16 may be required to tilt in the X and Y plane, for example when the bogie is cornering but with a fixed and unmovable valve, and this leads to the errors previously described.

Turning to an embodiment of the Applicant's design as shown in FIG. 2, the major difference, for present purposes is that the interface 17a is replaced by a wedge element 19 which bears on an inclined friction plate 20 to allow fore and aft and lateral movement of the wheel set 12 relative to the portion 11, whilst allowing the spring to maintain its vertical orientation. It will also be noted that a corresponding rearwardly inclined wedge and friction plate combination are shown at 19a and 20a respectively.

In this arrangement the wedge element 19 can be hollow to define a chamber within it and the load weigh valve 15 is mounted in the chamber for movement with the wedge element 19, so that it continually measures the vertical load.

In practice, railway vehicles, as is schematically shown at 21, have at least two bogies 10 and 10a. In this case load weigh valve 15 may be mounted on a rearwardly inclined wedge element 19a on one bogie and on the forwardly inclined wedge element, 19 on the other bogie. The outputs from these two load valves can be fed to a control device 22, which produces a mean of the two readings and uses this to generate a control output for a braking system 23, which controls the braking on the bogie wheels 24.

Claims

1. A railway bogie including, wheel set, a suspension for supporting a load on the wheel set, the suspension including at least one spring mounted on the wheel set; a wedge element for location between the load and spring to accommodate changes in vertical alignment between the load and wheel set and a load weigh valve for providing indication of the mass of the load as applied to the spring characterised in that the load weigh valve is mounted between the spring and wedge element for movement with the wedge element.

2. A railway bogie as claimed in claim 1 wherein the load weigh valve is mounted on the wedge element for movement therewith.

3. A railway bogie as claimed in claim 2 wherein the wedge element defines a chamber and the load weigh valve is mounted therein.

4. A railway vehicle having at least two bogies as claimed in claim 1 and wherein one bogie has at least a forward-inclined wedge element and the other bogie has at least a rearward inclined wedge element and; the load weigh valves are respectively on the forward and rearward inclined elements.

5. A vehicle as claimed in claim 4 further including a control device for providing a mean indication from the respective indications of the load weigh valves.

6. A vehicle as claimed in claim 5 including a controllable braking system responsive to the mean indication.