GB2421264A

GB2421264A - Rail bearer joint

Info

Publication number: GB2421264A
Application number: GB0427386A
Authority: GB
Inventors: Andrew Raymond Foan; Keith Churm
Original assignee: Balfour Beatty PLC
Current assignee: Balfour Beatty PLC
Priority date: 2004-12-14
Filing date: 2004-12-14
Publication date: 2006-06-21
Also published as: GB0427386D0; WO2006064216A1

Abstract

The joint comprises: first and second elongate rail bearers 3,5 arranged end to end; a connecting assembly connecting adjacent ends of the rail bearers, the connecting assembly having length adjusting means for adjusting a distance between the rail bearers and being articulated to allow relative vertical movement of the rail bearers; and means for resiliently restricting relative vertical movement of the rail bearers. The connecting assembly comprises a rod 9 with threaded ends in respective clevises 11,13 pivoted on shoulders 15,17 embedded in end or upper bearer surfaces. The resiliently restricting means is a resilient plug in end recesses of adjacent bearer surfaces (Fig 1, not shown), upper and lower steel plates 25,27 with synthetic rubber layers facing the bearer surfaces and clamped by a bolt 29, or wedges between the upper bearer surfaces and the clevises to limit tilting of the rod 9.

Description

1

2421264

RAIL BEARER JOINT

This invention relates to a joint of the type used to connect bearers for supporting rails.

5

Railway track is commonly supported on sleepers. Sleepers are elongate lengths of wood or concrete that are set into the ground and provide a level surface on which the rails-of the railway track are mounted. The sleepers are positioned perpendicular to the rails and are spaced at regular intervals along 10 the railway.

In general, railway junctions such as switches and crossings involve the convergence of two or more railway tracks, and the supports for these railway tracks are accordingly lengthened. These supports are called bearers. For 15 example, the bearers at railway junctions can be up to 8.5 metres long and carry six or more rails.

A problem associated with the bearers used for railway junctions relates to their transportation and manoeuvrability. In particular, it is difficult to transport and 20 manoeuvre bearers that are sufficiently long to accommodate all of the rails at a railway junction. In the case of wooden bearers, it is also difficult to manufacture sufficiently long bearers.

To overcome this problem, it is known to join together shorter bearers to form 25 long, composite bearers. A known joint for connecting bearers in this way is called a tie splice. A tie splice for concrete bearers comprises a threaded bar terminated at each end by a clevis. Each clevis rotates about a pin, which pin is attached to a respective bearer through an embedded shoulder. A similar device for connecting wooden bearers is also known.

30

The threaded section of the tie splice enables relative longitudinal adjustment of adjacent bearers, thereby providing adjustability of the distance between rails mounted on the adjacent bearers. The clevis assemblies of the tie splice

2

are also rotatable to enable relative vertical movement between the adjacent bearers. This form of articulation limits the transmission of vibrations between adjacent rail bearers, but also allows significant relative vertical movement of the rail bearers. The latter feature is of advantage if installing or maintaining 5 the part of a track layout track which includes only one of the adjacent bearers. In this event it may be permissible for the ends of the adjacent bearers to be held at different heights.

The clevis ends of the tie splice are asymmetric with respect to the axis of the 10 threaded section so that a half turn adjustment of a clevis causes a change in the lateral alignment of the bearers, thereby providing lateral adjustability. Shims may also be used in the assembly of the clevis to the embedded shoulder in order to effect such adjustment.

15 Another known joint for connecting bearers employs flat plates. Flat plates provide no facility for relative longitudinal or lateral adjustment and allow only limited relative vertical movement. Flat plates also incorporate some vibration damping capability.

20 According to the invention, there is provided a rail bearer joint comprising: first and second elongate rail bearers arranged end to end; a connecting assembly connecting adjacent ends of the rail bearers, the connecting assembly having length adjusting means for adjusting a distance between the rail bearers and being articulated to allow relative vertical movement of the rail bearers; and 25 means for resiliently restricting relative vertical movement of the rail bearers

The invention provides a rail bearer joint in which relative vertical movement is restricted, but in which the transmission of vibrations between the rail bearers may still be limited, especially vibrations in the vertical direction. The rail 30 bearer joint of the invention also allows for adjustment of the longitudinal distance between rail bearers. The invention avoids problems associated with excessive relative vertical movement of tie splices and lack of longitudinal adjustment of plates.

3

The connecting assembly preferably comprises a connecting bar running between the rail bearers. The length adjusting means may comprise a threaded bar engaged within a threaded bore. Relative rotation of the rod and 5 bore then provide the length adjustment. For example, in a particularly preferred embodiment, either end of a connecting bar may be threaded and engaged in the threaded bores of articulated portions of the connecting assembly.

10 Opposite ends of the connecting bar preferably comprise a revolute, i.e. hinged joint to allow for the relative vertical movement of the rail bearers. The joints preferably allow rotation of the connecting bar on a vertical plane through a longitudinal axis of the rail bearers. In a particularly preferred embodiment, the revolute joint comprises a clevis arranged to rotate about a pin, the clevis being 15 attached to the connecting bar and the pin being attached to an upper surface of the respective rail bearers, for example through an embedded shoulder.

The means for resiliently restricting relative vertical movement may comprise a resilient element mounted to opposing end surfaces of the respective rail 20 bearers. For example, the resilient element may be mounted in recesses formed in the opposing end surfaces of the respective rail bearers. In this way, restriction of relative vertical movement is provided regardless of the relative longitudinal positions of the rail bearers. The resilient element preferably comprises a plug moulded from a resilient material such as a rubber material.

25

Alternatively, the means for resiliently restricting relative vertical movement may comprise: upper and lower clamping plates spanning the upper and lower surfaces of the rail bearers respectively; and clamping means for clamping the plates together. At least one of the upper clamping plate, the lower clamping 30 plate and the clamping means preferably comprises or incorporates a resilient material, and this can provide the resilient restriction of relative vertical movement.

4

In either of the above means for resiliently restricting relative vertical movement, the extent and nature of the resilient restriction is dependent on the size, shape and elastic properties of the resilient material. In the case of the latter means, the extent and nature of the resilient restriction will also depend 5 on the clamping force of the clamping means.

Examples of the invention will now be described, by way of example only, with reference to the accompanying drawings in which:

Figure 1 is a schematic view of a first rail bearer joint according to the

10 invention; and

Figure 2 is a schematic view of a second rail bearer joint according to the invention.

Figures 1 and 2 show examples of a rail bearer joint according to the invention.

15 The Figures are schematic, intended for the purpose of explaining the invention, and are accordingly not drawn to scale. Moreover, the Figures omit some features for the sake of clarity, which features will be apparent to those skilled in the art.

20 Referring to Figure 1, a first rail bearer joint 1 according to the invention comprises first and second elongate concrete rail bearers 3, 5 arranged end to end, only the ends of which are shown. The concrete rail bearers 3, 5 have a substantially rectangular cross section.

25 The rail bearer joint 1 also comprises a connecting assembly 7 connecting adjacent ends of the first and second rail bearers 3, 5. The connecting assembly 7 comprises a connecting bar 9 connected at each of its ends to a respective clevis 11, 13. Each clevis 11, 13 is rotatable about a respective pin (not shown), which pin is mounted to a respective shoulder 15, 17 embedded in

30 an upper surface of a respective one of the rail bearers 3, 5.

The pins are mounted to be perpendicular to the longitudinal direction of the rail bearers 3, 5, and the clevises 11,13 are arranged so that the connecting bar 9

5

allows relative vertical movement of the rail bearers 3, 5. In the case of such movement, the connecting bar moves in a vertical plane that is parallel to a longitudinal axis of the rail bearers 3, 5.

5 The ends of the connecting bar 9 that are connected to the clevises 11,13 are threaded The clevises 11,13 are similarly formed with threaded bores. The connecting bar 9 is connected to the clevises 11, 13 by engagement of the respective like threads. With either clevis 11,13 removed from the embedded shoulder 15, 17, rotation of the clevis 11,13 relative to the threaded bar 9 and 10 the other clevis 11,13 causes a distance between the clevises 11, 13 to vary. This mechanism thus provides an effective means for accurately adjusting a longitudinal distance between the rail bearers 3, 5.

The rail bearer joint 1 also comprises a resilient plug 19 the opposite ends of 15 which are accommodated in opposing recesses 21, 23 in the ends of respective rail bearers 3, 5. The resilient plug is formed from a synthetic rubber material.

The shape and dimensions of the resilient plug 19 and the recesses 21, 23 are 20 such that relative vertical movement of the rail bearers 3, 5 is resiliently restricted, i.e. movement is allowed, but substantially only against the biasing force of the resilient material. Relative longitudinal movement of the rail bearers 3, 5 is not restricted by the resilient plug 19 but is restricted by the connecting assembly 7.

25

In use, the rail bearer joint 1 is assembled as shown in Figure 1. With one clevis 11,13 removed from the embedded shoulder 15, 17, the clevis 11, 13 is rotated relative to the connecting bar 9 and the other clevis 11, 13 so as to vary the longitudinal distance between the rail bearers 3, 5, and thereby adjust the 30 gauge of rails (not shown) mounted on the respective rail bearers 3, 5.

The articulated connecting assembly 7 and resilient plug 19 ensure that the transmission of vibrations, particularly in the vertical direction, between the rail

6

bearers 3, 5 is minimised while at the same time preventing significant relative vertical movement of the rail bearers 3, 5, such as long term differential settlement

5 Figure 2 shows a second rail bearer joint 1 according to the invention. The second rail bearer joint is similar to the first rail bearer joint and like elements have the same reference numbers.

Referring to Figure 2, the rail bearer joint 1 comprises first and second elongate 10 concrete rail bearers 3, 5 arranged end to end, only the ends of which are shown. The concrete rail bearers 3, 5 have a substantially rectangular cross section. The connecting assembly is the same as that shown in, and described with reference to, Figure 1.

15 Instead of a resilient plug 19, the rail bearer joint 1 comprises upper and lower clamping plates 25, 27 spanning upper and lower surfaces respectively of both rail bearers 3, 5. The clamping plates 25, 27 are steel plates with a resilient layer of synthetic rubber material on a face that contacts the rail bearers 3, 5. The clamping plates 25, 27 are clamped together by a bolt arrangement 29.

20

In use, the rail bearer joint 1 behaves in a similar way to that shown in Figure 1. Specifically, the gauge of rails (not shown) mounted on the respective rail bearers 3, 5 may be adjusted by rotation of a disconnected clevis 11, 13 relative to the other clevis 11, 13.

25

The articulated connecting assembly 7 and clamping arrangement 25, 27, 29 ensure that the transmission of vibrations, particularly in the vertical direction, between the rail bearers 3, 5 is minimised while at the same time preventing significant relative vertical movement of the rail bearers 3, 5.

30

Two specific examples of rail bearer joints according to the invention have been described. Various modifications may be made to the examples without

7

departing from the scope of the invention as defined by the claims. These modifications will be apparent to those skilled in the art.

For example, the means for resiliently restricting relative vertical movement of 5 the rail bearers may comprise an interference fit resilient wedge located between the clevises of the connecting assembly and the upper surfaces of the rail bearers. The resilient wedge restricts the angular movement of the connecting bar, thereby restricting relative vertical movement of the rail bearers.

10

While one form of connecting assembly is shown in the two examples described, others are possible. For example, the connecting assembly my be mounted to end faces of the rail bearers instead of their upper surfaces.

15

8

Claims

1. A rail bearer joint comprising:

first and second elongate rail bearers arranged end to end; 5 a connecting assembly connecting adjacent ends of the rail bearers, the connecting assembly having length adjusting means for adjusting a distance between the rail bearers and being articulated to allow relative vertical movement of the rail bearers; and means for resiliently restricting relative vertical movement of the rail 10 bearers.

2. The rail bearer joint of claim 1, wherein the connecting assembly comprises a connecting bar.

15

3. The rail bearer joint of claim 1 or 2, wherein the length adjusting means comprises a threaded bar engaged in a threaded bore, relative rotation of the rod and bore providing the length adjustment.

4. The rail bearer joint of any preceding claim, wherein opposite ends of 20 the connecting bar comprise a revolute joint to allow for the relative vertical movement of the rail bearers.

5. The rail bearer joint of claim 4, wherein the revolute joint comprises a clevis arranged to rotate about a pin.

25

6. The rail bearer joint of claim 4 or 5, wherein the revolute joints are attached to upper surfaces of the respective rail bearers.

7. The rail bearer joint of any preceding claim, wherein the means for 30 resiliently restricting relative vertical movement comprises a resilient element mounted to opposing end surfaces of the respective rail bearers.

9

8. The rail bearer joint of claim 7, wherein the resilient element is mounted in recesses formed in the opposing end surfaces of the respective rail bearers.

9. The rail bearer joint of claim 7 or 8, wherein the resilient element 5 comprises a plug moulded from a resilient material.

10. The rail bearer joint of any of claims 1 to 6, wherein the means for resiliently restricting relative vertical movement comprises a resilient element mounted to the connecting assembly.

10

11. The rail bearer joint of any of claims 1 to 6, wherein the means for resiliently restricting relative vertical movement comprises a resilient element mounted across top surfaces of the rail bearers between the rail bearers "and the connecting assembly.

15

12. The rail bearer joint of any of claims 1 to 6, wherein the means for resiliently restricting relative vertical movement comprises:

upper and lower clamping plates spanning the upper and lower surfaces of the rail bearers respectively; and 20 clamping means for clamping the plates together.

13. The rail bearer joint of any of claims 1 to 6, wherein the means for resiliently restricting relative vertical movement comprises:

laterally spaced clamping plates spanning opposite side surfaces of the 25 rail bearers respectively; and clamping means for clamping the plates together.

14 The rail bearer joint of claim 12 or 13, wherein at least one of the clamping plates and/or the clamping means comprises a resilient material

30

15. The rail bearer joint of any of claims 12 to 14, wherein the clamping means comprises a bolt.

10

16. A rail bearer joint as hereinbefore described or as shown in the drawings.