GB2363106A - Diaphragm for connecting rail vehicles - Google Patents

Abstract

The diaphragm 50 has a channel shaped cross section and corner regions 52 that are more flexible than the rest of the diaphragm. The increased flexibility of the corner regions may be provided by reducing the thickness of the material, by providing discrete insert portions, or by using a different material from that of the diaphragm. The diaphragm is arranged to fit between an interconnecting tunnel 10 and a vehicle 14 and has both horizontal and vertical limbs (figure 4). The channel shaped region of the diaphragm is composed of a web (54, figure 5a) with folded portions that provide flanges. The flanges allow the diaphragm to be attached to the tunnel and vehicle to close a gap between parts capable of relative motion about a pivot.

Description

2363106 JKWMPGIKLB/PI0607GB DIAPHRAGM This invention relates to a flexible

diaphragm for interconnecting two relatively rigid parts in a connection between two rail vehicles. This invention also relates to a connection between two rail vehicles comprising a diaphragm of said type.

A conventional rail vehicle connection is shown in Figure 1. A rigid tunnel section 10 defines a passageway between two adjacent rail vehicles 12 and 14. The ends 16 and 18 of the tunnel 10 are connected to the rail vehicles 12 and 14 by respective flexible rubber diaphragms 20 and 22. Rail vehicles 12 and 14 are also interconnected via their mechanical couplers 24 and 26 which are connected to their respective rail vehicles at pivots 28 and 30. The connection 32 established between couplers 24 and 26 is rigid.

When the train turns, the rail vehicles 12 and 14 move about pivots 28 and 30 relative to the rigidly interconnected cou plers 24 and 26. The tunnel 10 is attached by mechanical interconnection 34 to couplers 24 and 26 and hence is immobile relative thereto. Thus, when the train turns, or the vehicles 12 and 14 ride up and down, the vehicles 12 and 14 move relative to tunnel 10. Flexible diaphragms 20 and 22 accommodate the relative motion between the vehicles 12 and 14 and the tunnel 10 so as to maintain the integrity of the passageway.

The connection of diaphragm 22 is illustrated in more detail in Figure 2 (diaphragm 20 has a similar configuration). Diaphragm 22 has a generally channel-shaped cross-section having two flanges 36 and 38 and an intermediate web 43. Flange 38 is attached to a flange 40 of rail vehicle 14 and flange 36 is attached to an end 42 of the tunnel 10. Diaphragm 22 comprises vertical portions, such as 44, for absorbing horizontal motion between the tunnel 10 and the vehicle 14, and also comprises horizontal portions such as 46 for absorbing relative motion between the tunnel 10 and the vehicle 14 in a generally vertical plane.

For example, horizontal relative motion between the tunnel 10 and the vehicle 14 will lead to a narrowing of the gap between the tunnel 10 and one of the flanges (e.g. 40) on the vehicle. To accommodate this motion, which effectively moves the flanges 36 and 38 2 closer together, the web 43 rolls or presses outward, thereby increasing the depth of the channel shaped cross-section at the expense of its width. Thus, the web 43 of the diaphragm 22, in particular, is deformed and since the vehicles 12 and 14 are in almost constant relative motion, the deformation of the web 43 is continuously changing.

Horizontal motion between the tunnel 10 and vehicle 14 will also cause a relative longitudinal movement between flanges 36 and 38 of the horizontal portions 46 of the diaphragm 22. This in turn causes a shearing motion in the web 43. At the comer where the vertical and horizontal portions 44, 46 meet, the shearing motion causes a complex folding of the diaphragm 22 which leads to high wear in these regions.

It is an object of the invention to provide a flexible diaphragm, for interconnecting two relatively rigid parts in a connection between two rail vehicles, the flexible diaphragm having improved wear resistance.

According to one aspect, the invention provides a flexible diaphragm for closing an elongate gap between two relatively moveable parts in a connection between two rail vehicles, the diaphragm having at least one comer to accommodate changes in the direction of the gap, wherein said comer is adapted to be more flexible than adjacent regions of the diaphragm.

By enhancing the flexibility of a comer region, the comer region can more easily undergo complex or repetitive folding due to shearing motion without damage, and is less susceptible to wear.

The diaphragm may have a cross-section comprising a web extending between two flanges and have means for connecting it between the relatively rigid parts such that the web is closer than the flanges to a pivot about which the parts move.

According to a second aspect, the invention provides a flexible diaphragrn for a rail vehicle interconnection, to close a gap between parts capable of relative motion about a pivot, the diaphragm having a channel-shaped cross-section defined by a web extending between two I I 3 flanges, wherein the diaphragm is adapted to be connected to said parts such that the web extends from the flanges towards the pivot.

For a given angular relative motion of the two parts about the pivot, the linear displacement increases with distance from the pivot. By providing that the web is close to the pivot, it is possible to reduce the motion experienced by the web in response to a movement, thereby reducing wear to the web.

given angular In a preferred embodiment, a comer region of enhanced flexibility is provided by reducing the thickness of the diaphragm in the comer region and/or making the comer region from a more flexible material.

The diaphragm may be a collar attached to an end of at least one of the parts.

Where the flexible diaphragm has a channel-shaped cross-section comprising a web extending between two flanges, an exterior return-flange may be provided at the free end of each of said flanges, the exterior flanges being used to connect the diaphragm in place.

The diaphragm may have a generally convolute cross section.

In one embodiment, the flexible diaphragm connects a rail vehicle with a rigid member delimiting a passageway to an adjacent rail vehicle.

In another embodiment, the flexible diaphragm provides a gangway between two interconnected rail vehicles. The gangway may allow, for example, passengers to move from one vehicle to another.

By way of example only, certain embodiments of the invention will now be described with reference to the accompanying figures, in which:

Figure 1_ is a schematic side elevation of a connection between two rail vehicles; Figure 2 is a partially cut away perspective drawing of a rail vehicle interconnection comprising a conventional diaphragm; Figure 3 is a partially cut away perspective drawing of a rail vehicle interconnection comprising a different diaphragm; Fiaure 4 is an end elevation of a comer region of the diaphragm of Figure 3 viewed towards the rail vehicle; FiP,ure 5a is a cross-section on line A-A in Figure 4; Figure 5b is an analogous cross-section through a similar diaphragm; Figure 6 is a schematic cross-section through a gangway connecting two rail vehicles; and Figure 7 is a cross-section on line B-B in Figure 6.

The interconnection shown in Figure 3 is similar to that shown in Figure 2, except in that a different diaphragm 50, of nylon reinforced rubber, is used. For brevity, features of the rail interconnection of Figure 3 which have already been described with reference to Figures I and 2 will not be described in detail again. The cross-section of diaphragm 50 comprises a major portion which is channel-shaped, defined (as shown in Figure 5) by a web 54 extending between two interior flanges, 53 and 55. The diaphragm 50 is arranged to fit between the tunnel 10 and the vehicle 14 such that the web attains a minimum distance to the pivot 30 which constrains movement between the tunnel 10 and the vehicle 14.

When the vehicle 14 and the tunnel 10 move together so as to narrow the gap therebetween, the material of the diaphragm 50 will roll inward (towards vehicle 14), deepening the channel-shaped cross-section. The relative motion between the tunnel 10 and the vehicle 14 includes a jitter (i.e. an oscillatory motion of relatively low amplitude) inherent in the motion of the train. This jitter causes an oscillatory rolling of the diaphragm 50. The amount of this rolling motion is dependent upon the relative motion between the tunnel 10 and the vehicle 14, as described by the relative angular displacement of the vehicle 14 and the tunnel 10 about the pivot 30. By arranging that the web 54 of the diaphragm 50 is as close as possible to the pivot 30, it is provided that the amplitude of the rolling motion due to a given angular displacement about the pivot 30 is minimised. By minimising the rolling motion in this way, the material of the diaphragm is subjected to less repetitive flexing, thus enhancing the lifetime of the diaphragm 50.

The comer regions 52 of the diaphragm 50 are inserts of a material which is thinner than that of the main vertical and horizontal limbs of the diaphragm 50. This means that the comers 52 are more flexible and hence are more able to accommodate the complex comer folding due to the earlierdescribed shear-motion. In the past, the solution to the problem of high wear (manifested by cracking) in the comer regions has been to thicken the diaphragm in such regions to reduce the effect of any cracks which appear. However, the thicker the diaphragm is made, then the greater the difference becomes between the inner and outer dimensions in the region of a fold. The greater this difference becomes, the greater the load on the diaphragm will be, hence exacerbating cracking.

A so-called soft comer region 52 is shown more clearly in Figure 4. The insert 52 is glued and stitched into the diaphragm 50.

As shown in Figure 5a, the diaphragm 50 has a web 54 bounded by interior flanges 53 and 55. The material of the diaphragm 50 is folded to produce the ends 60 and 62 of the interior flanges 53 and 55 and provide the exterior flanges 56 and 58. The material of the diaphragm 50 is stitched (denoted 64 and 66) and glued in the region of the ends 60 and 62 of the interior flanges 53 and 55 to reinforce the structure and to fix the exterior flanges 56 and 58 in position. One of the exterior flanges 56 connects, in use, to the tunnel 10 and the other exterior flange 58 connects to flange 40 of rail vehicle 14. The exterior flanges 56 and 58 therefore provide the means by which the diaphragm 50 is attached between the tunnel 10 and the vehicle 14, and allow the connection to be made without substantially modifying the turniel 10 or the vehicle 14.

Figure 5b illustrates an alternative construction of the diaphragm, where the exterior flanges 56 and 58 are provided as separate pieces which are attached by gluing and stitching to the ends 60 and 62 of the interior flanges 53 and 55. The three-piece construction of Figure 5b may be easier to produce than the unitary construction of Figure 5a since the material of the diaphragm does not have to be folded (although, conversely, folding the material may lead to a structure with beneficially enhanced rigidity).

Figure 6 shows a cross-section along the axis of a connection between two rail vehicles 68 and 70 by means of a flexible corrugated tunnel 72. The gangway 72 comprises a series of annular segments 73, connected end-toend. Each segment 73 has an oval cross-section 75 defined by manufacturing each segment from a pair of convolutes 76 and 78 whose concave sides face each other. One convolute 76 serves to define the inner wall of the gangway 72 and the other convolute 78 defines the outer wall of gangway 72.

The tunnel 72 is subject to creasing and wear at its comers. Therefore, as shown in Figure 7, the comers 74 of the segments 73 are provided by thinner sections than the side walls of the gangway 72. The comers 74 may be provided by inserts of thinner material. The thinned comers of gangway 72 function like the soft comers described with reference to Figures 3 to 5b to reduce wear of the gangway 72.

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Claims (13)

1. A flexible diaphragm for closing an elongate gap between two relatively moveable parts in a connection between two rail vehicles, the diaphragm having at least one comer to accommodate changes in direction of the gap, wherein at least one comer is a flexible comer, the or each flexible comer being adapted to be more flexible than adjacent regions of the diaphragm.

2. A diaphragm according to claim 1, wherein at least one flexible comer is provided by reducing the thickness of the diaphragm in the comer compared to adjacent regions of the diaphragm.

3. A diaphragm according to claim I or 2, wherein at least one flexible comer is provided by using a material for the comer which is different to the material of adjacent regions of the diaphragm.

4. A diaphragm according to claim 1, 2 or 3, wherein at least one flexible comer is an insert discrete from adjacent regions of the diaphragm.

5. A diaphragm according to any one of claims 1 to 4, wherein the diaphragm provides a passageway between the said rail vehicles.

6. A diaphragm according to claim 5, wherein the or each flexible comer is at an intersection of surfaces of the passageway.

7. A diaphragm according to claim 5 or 6, wherein the diaphragm has inner and outer layers.

8. A diaphragm according to any one of claims I to 4, wherein the diaphragm comprises a web extending between two web flanges, and is adapted to be connected between said moveable parts such that the web extends from the web flanges towards a pivot about which said moveable parts move.

9. A flexible diaphragm for a rail vehicle connection to close a gap between parts capable of relative motion about a pivot, the diaphragm having a channel shaped cross-section defined by a web extending between two web flanges, wherein the diaphragm is adapted to be connected to said parts such that the web extends from the web flanges towards the pivot.

10. A diaphragm according to claim 8 or 9, further comprising an exterior return flange at the free end of each of said web flanges, said return flanges being used to connect the diaphragm in place.

11. A diaphragm according to claim 10, wherein the return flanges are formed by folding the web flanges.

12. A diaphragm according to claim 10, wherein the return flanges are discrete elements attached to the web flanges.

13. A flexible diaphragm for a rail vehicle connection, substantially as hereinbefore described with reference to 3 to 5b or Figures 6 and 7.