AU1544999A - A suspension system for a railway carriage - Google Patents

Description

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

a a Name of Applicant: Actual Inventor: Address of Service: ERIC R. WHITELEY Eric R. WHITELEY BALDWIN SHELSTON WATERS MARGARET STREET SYDNEY NSW 2000 Invention Title: "A SUSPENSION SYSTEM FOR A RAILWAY CARRIAGE" Details of Associated Provisional Application No. PP1657 dated 5th February 1998 The following statement is a full description of this invention, including the best method of performing it known to me:- -2- The present invention relates to suspension and in particular to a suspension system for a railway carriage.

The invention has been developed primarily for mounting between the body and one of the bogies of a railway carriage and will described hereinafter with reference to that application. However, it will be appreciated that the invention is not limited to that particular field of use.

Known railway carriage suspension typically links a bogie to a car body by means of two air-springs disposed to control the vertical separation between the bogie and the car body. These known arrangements typically provide bump-stops disposed to interact 10 between the car body and the bogie to constrain lateral movement therebetween within given limits.

~One of the disadvantages of such an arrangement, particularly on poorly aligned tracks, is a jerky and uncomfortable ride. Additionally, sustained lateral forces may result in sustained engagement of one or both of the bump-stops, thereby transferring o• lateral forces directly from the bogie to the car.

It is an object of the present invention, at least in the preferred embodiment, to overcome or substantially ameliorate one or more of the disadvantages of the prior art.

According to a first aspect of the invention there is provided a suspension system for a railway carriage having a car body mounted to and being laterally displaceable with respect to a bogie, the system including a first and a second fluid-spring for providing, when subject to compression, a first and a second resilient reaction force in opposition to said compression, the fluid-springs being disposed intermediate of the car body and the bogie such that the first force acts between the car body and the bogie in a direction generally opposite to the second force, so as to resist relative lateral displacement between the car body and the bogie.

Preferably, the first and second fluid-springs are disposed on either side of a projection depending from the car body. In alternative preferred embodiments, the first and second fluid-springs are disposed on either side of a portion of the bogie and are flanked by projections depending from the car body.

The first and second fluid-springs preferably releasably abut either the bogie or the car body so as to retract therefrom upon deflation.

According to another aspect of the invention there is provided a railway carriage including a car body mounted to a bogie by means of a suspension system as described above.

A preferred embodiment of the invention will now be described, by way of oo example only, with reference to the accompanying drawings in which: Figure 1 is a schematic plan view of a system according the invention, the car body being shown in ghost; Figure 2 is a cross-sectional end elevation of the system depicted in figure 1, taken along line 2-2; Figure 3 is an expanded cross-sectional elevation of a portion of a system according to an embodiment of the invention; Figure 4 is a plan view of the bogie shown in figure 3; Figure 5 is an end elevation of an alternative embodiment of the invention; Figure 6 is a side elevation of the embodiment shown in figure 5; and Figure 7 is a plan view of the embodiment shown in figure -4- Referring to the drawings, the suspension system 10 is for a railway carriage 11 having a car body 12 mounted to and being laterally displaceable with respect to a bogie 14. The system 10 includes first and second fluid-springs 16 and 18 for providing, when subject to compression, a first and second resilient reaction force in opposition to the compression. The fluid-springs 16 and 18 are disposed intermediate of the car body 12 and the bogie 14 such that the first force acts between the car body and the bogie in a direction generally opposite to the second force. The opposing forces resist lateral displacement of the car body 12 with respect to the bogie 14. At static equilibrium, the o* S.

opposing forces tend to center the car body with respect to the bogie.

In the embodiment shown in figure 1 and 2, the first and second fluid-springs 16 and 18 are disposed on either side of a projection 20 depending from the car body 12. In the embodiment shown in figures 3 and 4 the fluid-springs 16 and 18 are disposed on S- either side of the bogie 14 and act upon the car body 12 via projections 20 depending therefrom.

o.

The system 10 further includes third and fourth fluid-springs 22 and 24 disposed ~between the bogie 14 and the car body 12 such that the resilient reaction forces of the third and fourth fluid-springs act in the same direction so as to urge the car body 12 to maintain a separation distance from the bogie 12. In practice, the third and fourth fluidsprings 22 and 24 are responsible for controlling vertical movement between the bogie 14 and the car body 12.

The fluid pressure of each fluid-spring 16, 18, 22 and 24 is independently adjustable so as to tune the respective spring constants of the fluid-springs.

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The fluid-springs communicate with a pressure source 26. In alternative embodiments, the third and fourth fluid-springs 22 and 24 communicate with a primary fluid pressure source and the first and second fluid-springs 16 and 18 communicate with an auxiliary pressure source.

The system 10 also includes a pneumatic control system 28 adapted to separately control the pressures of the first and second springs 16 and 18, or alternatively to separately control the pressures of the all of the fluid-springs.

The pneumatic control system 28 is adapted to sense a pressure loss associated with a failure of either the first or second spring 16 or 18 and reduce the pressure in the opposing spring to maintain a balance between the first and second springs. In the ounlikely event of a rupture of one or both of the first or second air springs 16 or 18, the system simply reverts to an operational performance similar to that of the prior art described in the introductory portion of this specification. In other words, the system remains operational, but without enhanced lateral control.

In an alternative embodiment, the pneumatic control system 28 is further adapted to dynamically alter the pressure in any of the springs according to the instantaneous loads applied thereto so as to cause the springs to urge the bogie 14 to adopt a predetermined relationship with the car body 12. In other words, this alternative embodiment provides active suspension.

In the preferred embodiments, the fluid-springs 16, 18, 22 and 24 are pressurised by air, however various other gases or liquids known to those skilled in the art may be utilised for this purpose.

-6- The first and second fluid-springs 16 and 18 include internal bump-stops disposed to engage the car body 12 and the bogie 14 when a predefined limit of lateral displacement there between has been reached.

The first and second fluid-springs 16 and 18 are mounted to the bogie 14 so as to releasably abut the car body 12 via the projection 20 depending therefrom. This arrangement facilitates removal of the car body from the bogie. The first and second fluid-springs 16 and 18 each include plates 32 disposed to abut the car body 12, via the projection 20, upon inflation of the springs. Upon deflation of the springs, the plates 32 retract from the projection 20. In an alternative embodiment, the first and second fluid- 10 springs are mounted to the projection 20, so as to releasably abut the bogie 14.

The cross-sectional shape of the first and second air-springs 16 and 18 are designed so as to maximise the contact area of the springs upon the bogie 14 and the car Sbody 12. This advantageously maximises the force transmitted by the springs for a given pressure. For example, if a square area is available for exerting pressure between the car body 12 and the bogie 14, the cross-sectional shape of the first and second air- S°springs would closely approximate that square area.

Figures 5, 6 and 7 illustrate an alternative embodiment of the invention as applied to a different type of bogie. These figures illustrate one half of the system wherein the first fluid-spring 34 is disposed intermediate the bogie frame 36 and a centre pivot 38 which is attached to the car body. Although not illustrated in figures 5, 6 or 7, a second fluid-spring is disposed opposite the first fluid-spring 34 so as to control lateral movement between the bogie frame 36 and the centre pivot 38 in a similar manner to that described above.

-7- Although the invention has been described with reference to specific examples, it will be appreciated by those skilled in the art that the invention may be embodied in many other forms.

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Claims (16)

1. A suspension system for a railway carriage having a car body mounted to and being laterally displaceable with respect to a bogie, the system including a first and a second fluid-spring for providing, when subject to compression, a first and a second resilient reaction force in opposition to said compression, the fluid-springs being disposed intermediate of the car body and the bogie such that the first force acts between the car body and the bogie in a direction generally opposite to the second force, so as to resist relative lateral displacement between the car body and the bogie.

2. A system for controlling lateral displacement of a car body with respect to a bogie according to claim 1 wherein said first and second fluid-springs are disposed on either side ofa projection depending from said car body.

3. A system for controlling lateral displacement of a car body with respect to a 0 bogie according to claim 1 wherein the first and second fluid-springs are disposed on •.either side of a portion of the bogie and are flanked by projections depending from the car body.

4. A system for controlling lateral displacement of a car body with respect to a bogie according to any one of the preceding claims further including third and fourth fluid-springs disposed between said bogie and said car body such that resilient reaction forces of said third and fourth fluid-springs act in the same direction so as to urge said car body to maintain a separation distance from said bogie. A system for controlling lateral displacement of a car body with respect to a bogie according to any one of the preceding claims wherein the fluid pressure of each -9- fluid-spring is independently adjustable so as to tune the respective spring constants of the fluid-springs.

6. A system for controlling lateral displacement of a car body with respect to a bogie according to claim 4 wherein said third and fourth fluid-springs communicate with a primary fluid pressure source and said first and second fluid-springs communicate with an axillary pressure source.

7. A system for controlling lateral displacement of a car body with respect to a bogie according to any one of the preceding claims further including a pneumatic control system adapted to separately control the pressures of said first and second fluid-springs.

8. A system for controlling lateral displacement of a car body with respect to a bogie according to claim 7 wherein the pneumatic control system is adapted to sense a ~pressure loss associated with a failure of either the first or second spring and to reduce the pressure in the opposing spring to maintain a balance between the first and second springs.

9. A system for controlling lateral displacement of a car body with respect to a ~bogie according to claim 7 or 8 wherein said pneumatic control system is further adapted to dynamically alter the pressure in any one of the springs according to instantaneous loads applied thereto so as to cause the springs to urge the bogie to adopt a predetermined relationship with said car body.

10. A system for controlling lateral displacement of a car body with respect to a bogie according to any one of the preceding claims wherein said fluid-springs are pressurised by air.

11. A system for controlling lateral displacement of a car body with respect to a bogie according to any one of the preceding claims wherein said first and second fluid- springs include internal bump-stops disposed to engage said car body and said bogie when a predefined limit of lateral displacement therebetween has been reached.

12. A system for controlling lateral displacement of a car body with respect to a bogie according to any one of the preceding claims wherein said first and second fluid- springs are mounted to said bogie so as to releasably abut said car body, thereby facilitating removal of the car body from said bogie.

13. A system for controlling lateral displacement of a car body with respect to a o• bogie according to claim 12 wherein said first and second fluid-springs each include plates disposed to abut the car body upon inflation of the springs and to retract from the car body upon deflation of said springs. °14. A system for controlling lateral displacement of a car body with respect to a bogie according to any one of claims 1 to 11 wherein said first and second fluid-springs are mounted to said car body so as to releasable abut said bogie, thereby facilitating removal of the car body from said bogie. A system for controlling lateral displacement of a car body with respect to a bogie according to claim 14 wherein said first and second fluid-springs each include plates disposed to abut the bogie upon inflation of the springs and to retract from the bogie upon deflation of said springs.

16. A system for controlling lateral displacement of a car body with respect to a bogie according to any one of the preceding claims wherein a cross sectional shape of the first and second fluid-springs tends to maximise the contact area of said springs upon -11- the bogie and the car body so as to maximise a force transmitted by said springs for a given pressure.

17. A suspension system for controlling lateral displacement of a car body with respect to a bogie according to claim 16 wherein contact regions of the car and/or bogie s upon which the first and second fluid-springs act have a shape which generally corresponds to said cross sectional shape of said first and second fluid-springs.

18. A railway carriage including a car body mounted to a bogie by means of a suspension system according to any one of the preceding claims.

919. A system for controlling lateral displacement of a car body with respect to a 10 bogie substantially as herein described with reference to any one of the embodiments of i the invention as depicted in the accompanying drawings. A railway carriage substantially as herein described with reference to any one of the embodiments of the invention as depicted in the accompanying drawings DATEDthis 5th Day of February, 1999 9o ERIC R. WHITELEY Attorney: PHILLIP D. PLUCK Associate Institute of Patent Attorneys of Australia of BALDWIN SHELSTON WATERS