WO2019079858A1

WO2019079858A1 - An improved rail tensor

Info

Publication number: WO2019079858A1
Application number: PCT/AU2018/051155
Authority: WO
Inventors: Andrew Melvelle; Gary Morris; Ben de Rooy
Original assignee: Melvelle Equipment Corp. Pty Ltd
Priority date: 2017-10-27
Filing date: 2018-10-26
Publication date: 2019-05-02

Abstract

The present invention relates broadly to a rail tensor (10) to be installed for operation on a rail member (12) associated with a plinth style sleeper (14). The rail tensor (10) generally comprises a bridge coupling assembly (16) coupled at each of its opposing ends to appear of opposing time members (18a) and (18b) and a pair of opposing tensioning members (20a) and (20b), respectively. The rail tensor (10) also comprises a first grip member (22) connected to an end of the opposing time members (18a/b), and a second grip member (24) connected to the pair of tensioning members 20a/b. The bridge coupling assembly (16) is positioned at a weld joint (26) of the rail member (12) with the first and second grip members (22) and (24) adapted to grip the rail member (12) on opposite sides of the weld joint (26). The rail tensor (10) is thus arranged for pre-stressing of the rail member (12) prior to applying the weld joint (26).

Description

AN IMPROVED RAIL TENSOR

Technical Field

[0001 ] The present invention relates broadly to a rail tensor and relates particularly, although not exclusively, to a rail tensor for use on railway track associated with plinth style sleepers.

Background of Invention

[0002] In the course of joining railway track by welding it is necessary to prestress the adjoining rail members. This prestressing ensures the track is effectively stress free at an ambient temperature of around 35°C. At lower temperatures the track is in tension and at higher temperatures it moves into a state of compression but with a reduced risk of buckling. The adjoining rail members are typically welded together in a butt joint using an exothermic or thermite welding process. The general steps involved in joining the track are as follows: i) the separated members are pulled toward one another using a rail tensor; ii) the prestressed track members are welded together using a thermite weld mould which encloses the adjoining regions of the track;

iii) the termite weld is sheared and ground to match the profile of the track; iv) the joined rail members are released from the rail tensor;

v) the track is clipped or otherwise fastened to its associated sleepers.

[0003] The conventional rail tensor includes two pairs of jaws separated longitudinally by a pair of tension rods arranged parallel to one another. The tensor usually includes a pair of relatively large hydraulically actuated cylinders dedicated to respective of the tension rods. In operation the pair of jaws are positioned to grip the rail member either said of the joint to be welded and the large cylinders actuated to draw the separated rail members toward one another in preparation for welding. The pair of tension rods must be laterally separated a distance sufficient to accommodate the thermite weld mould. The large cylinders are aligned with their respective tension rods, and the pairs of jaws coupled to respective ends of the cylinders and tension rods. The rail tensor is thus relatively bulky and limited in its application to traditional railway construction where rail members are supported on timber or concrete sleepers laid on stone ballast. The rail tensor does not lend itself to application with railway track associated with plinth style sleepers where space alongside the rail member is limited by the presence of the plinth sleeper.

Summary of Invention

[0004] According to an aspect of the present invention there is provided a rail tensor comprising:

a first grip member adapted to grip a rail member one side of a weld joint in the rail member;

a second grip member adapted to grip the rail member on an opposite side of the weld joint in the rail member;

a pair of opposing tie members at one end connected to the first grip member;

a pair of opposing tensioning members at one end operatively coupled to the second grip member;

a first coupling configured to bridge the rail member on said one side of the weld joint, said first coupling connected to an opposite end of the pair of tie members;

a second coupling configured to bridge the rail member on the opposite side of the weld joint, said second coupling coupled to an opposite end of the pair of tensioning members;

a pair of linkage members each at opposing ends connect to respective of the first coupling and the second coupling, the first and second couplings arranged to laterally space the pair of linkage members more distant from one another relative to lateral spacing of the pair of tie members and/or the pair of tensioning members.

[0005] Preferably the first and/or second coupling includes a bridge member adapted to transversely bridge the rail member, and a pair of posts rigidly mounted to the bridge member at or adjacent its opposing ends whereby said posts are positioned in a substantially vertical disposition either side of the rail member. More preferably said coupling includes a mounting bracket rigidly secured to each of the posts, the mounting bracket arranged to provide anchorage for one of the linkage members and either one of the tensioning members or one of the tie members. Still more preferably the mounting brackets are each configured relative to the posts to provide anchorage of the linkage members more distant from one another relative to the lateral spacing of the tie members and/or tensioning members.

[0006] Preferably each of the mounting brackets includes an upper and a lower plate rigidly connected to and vertically spaced along the post, said plates being shaped to separate anchorage of the linkage member and including two aligned pairs of openings. More preferably each of the pair of openings is designed to retractably receive a coupling pin for anchoring one of the linkage members and either one of the tensioning or tie members. Still more preferably one of the pair of openings providing anchorage for the linkage member has a greater lateral spacing from the rail member relative to the other pair of openings providing anchorage for either the tie member or the tensioning member.

[0007] Preferably the first grip member and/or the second grip member includes a pair of opposing jaws adapted to grip the rail member. More preferably the pair of opposing jaws are interconnected by a crossbar which extends transversely across the rail member. Even more preferably the jaws are each in the form of a cam member pivotally coupled to the crossbar for gripping of the rail member.

[0008] Preferably the pair of opposing tensioning members each includes a hydraulically actuated cylinder including a cylinder housing anchored to one of either the first or the second pair of jaws, and a piston rod anchored to the second coupling.

[0009] Preferably the rail member is associated with plinth style sleepers.

Brief Description of Drawings

[0010] In order to achieve a better understanding of the nature of the present invention a preferred embodiment of a rail tensor will now be described, by way of example only, with reference to the accompany drawings in which:

Figure 1 is a perspective view of a rail tensor according to one embodiment of the invention installed on a rail member associated with plinth style sleepers;

Figure 2 is an elevational view of the rail tensor of figure 1 ; Figure 3 is a plan view of the rail tensor of figures 1 and 2;

Figure 4 is an enlarged perspective view of one end of the rail tensor of the preceding figures;

Figure 5 is an enlarged perspective view of another end of the rail tensor of figures 1 to 3;

Figures 6A and 6B illustrate in Finite Element Analysis (FEA) stresses present in components of the bridge coupling and the associated linkage members in the course of operating the rail tensor.

Detailed Description

[001 1 ] As seen in figures 1 to 3, there is a rail tensor 10 according to one embodiment of the invention and in operation installed on a rail member 12

associated with a plinth style sleeper 14. The rail tensor 10 generally comprises a bridge coupling assembly 16 coupled at each of its opposing ends to a pair of opposing tie members 18a and 18b and a pair of opposing tensioning members 20a and 20b, respectively. The rail tensor 10 also comprises a first grip member 22 connected to an end of the opposing tie members 18a/b, and a second grip member 24 connected to the pair of tensioning members 20a/b.

[0012] In this embodiment the bridge coupling assembly 16 is positioned at a weld joint 26 of the rail member 12 with the first and second grip members 22 and 24 adapted to grip the rail member 12 on opposite sides of the weld joint 26. The rail tensor 10 is thus arranged in a conventional manner for pre-stressing of the rail member 12 prior to applying the weld joint 26. The weld joint 26 is typically applied as a thermite weld utilising a thermite mould 28 in a conventional manner. On

completion of the weld joint 26, the rail tensor 10 is released and the rail member 12 clipped or otherwise fastened to the plinth style sleeper 14.

[0013] In this embodiment the bridge coupling assembly 16 comprises first and second couplings 30a and 30b configured to bridge the rail member 12 on opposing sides of the weld joint 26, respectively. The first and second couplings 30a/b are interconnected via a pair of linkage members 34a and 34b disposed parallel to one another on either side of the rail member 12. The first and second couplings 30a/b are thus arranged to laterally space the pair of linkage members 34a/b sufficient distance to accommodate the thermite mould 28. The first and second couplings 30a/b also serve to laterally space the pair of tie members 18a/b and tensioning members 20a/b at a reduced distance from one another relative to the lateral spacing of the pair of linkage members 34a/b. It will be understood that this reduced separation of in particular the pair tensioning members 20a/b is suited to installation of the rail tensor 10 on rail members associated with plinth style sleepers where there is limited space. In this embodiment and as best seen in figure 3, the width of the bridge coupling assembly 16 is approximately equal to the maximum outer lateral separation of the tensioning members 20/b.

[0014] Figures 4 and 5 best illustrate the first and second couplings 30a/b of the bridge coupling assembly 16 of this embodiment of the invention. The first and second couplings 30a/b are of substantially identical construction and in order to avoid repetition this detailed description will be limited to the first coupling 30a, noting that the second coupling 30b has corresponding components. For example, the first coupling 30a includes a bridge member 36a adapted to bridge the rail member 12 and the corresponding bridge member of the second coupling 30b is designated 36b. The bridge member 36a transversely bridges the rail member 12 and is at its opposing ends rigidly connected to respective of a pair of posts 38a and 40a positioned in a substantially vertical disposition either side of the rail member 12. The first coupling 30a includes a mounting bracket 42a and 44a rigidly secured to respective of the posts 38a and 40a. The mounting brackets such as 44a provide anchorage for one of the linkage members 34b and one of the tie members 18b. As described in the context of the bridge coupling assembly 16 and the thermite mould 28, the mounting brackets 42a and 44a are configured to provide anchorage of the linkage members 34a and 34b more distant from one another relative to the lateral spacing of the tie members 18a/b and the tensioning members 20a/b.

[0015] In this embodiment each of the mounting brackets such as 44a includes an upper and a lower plate 46a and 48a rigidly connected to and vertically spaced along the post 40a. The plates 46a and 48a are in profile curve-shaped to provide the increased lateral separation and anchorage of the linkage members 34a/b. In this example the vertically separated plates 46a and 48a include two pairs of aligned openings, each of the pairs designed to retractably receive respective coupling pins 50aa and 50ab. One of the coupling pins 50aa anchors one of the tie members 18b whereas the other of the coupling pins 50ab anchors one of the linkage members 34b. It will be understood that the lateral separation between the coupling pins such as 50ab associated with the linkage members such as 34b is greater than the lateral spacing or separation of the coupling pins such as 50aa associated with the tie members such as 18b. As explained earlier, this increased lateral separation of the linkage members 34a and 34b provides sufficient space to accommodate the thermite mould 28 or other equipment associated with forming the weld joint in the rail member 12.

[0016] As best seen in figure 5, the pair of opposing tensioning members 20a/b are in the form of a pair of hydraulically actuated cylinders. The hydraulically actuated cylinders such as 20a each include a cylinder housing 54a coupled to the second grip member 24, and an associated piston rod 56a anchored to the second coupling 30b. The second grip member 24 of this example includes a pair of opposing jaws 58a and 60a adapted to grip the rail member 12. The pair of opposing jaws 58a and 60a are interconnected by a crossbar 62a which extends transversely across the rail member 12. The jaws 58a and 60a are each in the form of a cam member pivotally coupled to the crossbar 62a for gripping of the rail member 12 on operation of the rail tensor 10. The cylinder housing 54a is anchored to the cam member 58a which is pivotally mounted to the crossbar 62 via pivot shaft 64a on one side of the rail member 12. The opposing cylinder housing 54b is anchored to the associated cam member 60a which is arranged to pivot about the crossbar 62a via another pivot shaft 64b. The piston rod 56a is anchored to the second coupling 30b via the associated coupling pin 52ba, and the other piston rod 56b is anchored to the second coupling 30b via the coupling pin 50ba.

[0017] As best seen in figure 4, the first grip member 22 includes a pair of opposing jaws 68a and 70a adapted to grip the rail member 12. The first grip member 22 is otherwise of substantially the same construction as the second grip member 24 including a crossbar 72a and a pair of opposing pivot shafts 74a and 74b dedicated to respective of the jaws or cam members 68a and 70a. The tie bar 18a is anchored to the first coupling 30a via the associated coupling pin 52ba, and the other tie bar 18b is anchored to the first coupling 30a via the coupling pin 50aa.

[0018] In operation, the rail tensor 10 may apply stress loads of up to around 70 tonne in tensioning the rail member 12 prior to welding. Each of the hydraulically actuated cylinders 20a and 20b thus provides up to around 35 tonne in tension force in order to adequately prestress the rail member 12. Figures 6A and 6B illustrate in Finite Element Analysis (FEA) stresses imposed on components of the rail tensor 10 in prestressing the rail member 12. The FEA shows stresses within opposing sides of the second coupling 30b together with its associated linkage member 34b, and piston rod 56b. The stresses in these components vary from as low as round 0.2MPa to as high as around 940MPa in very localised regions. It can otherwise be seen from the FEA that the design of the bridge coupling assembly 16 in this embodiment evenly distributes stresses within the coupling assembly 16 with the highest stresses being in the linkage members such as 34b and the piston rods such as 20b.

[0019] Now that a preferred embodiment of the present invention has been described, it will be apparent to those skilled in the art that the rail tensor has at least the following advantages:

1 . the rail tensor is of a relatively compact design permitting its installation and operation on rail members associated with plinth style sleepers;

2. the rail tensor and in particular the associated bridge coupling assembly is of a configuration which provides sufficient space for tooling including a mould associated with thermite welding;

3. the rail tensor includes a pair of relatively large hydraulically actuated

cylinders for prestressing to the relatively high required loads whilst maintaining its compact design;

4. the bridge coupling assembly is effective in distancing the hydraulically actuated cylinders from the elevated temperatures of the weld joint which may otherwise compromise or damage components, such as hydraulic seals, of the cylinders.

[0020] Those skilled in the art will appreciated that the invention described herein is susceptible to variations and modifications other than those specifically described. For example, the first and/or second couplings may vary in their configuration provided the associated linkage members are adequately separated to accommodate the necessary welding equipment. The demountable nature of the rail tensor may, subject largely to its size and weight restrictions, depart from the preferred

embodiment where, for example, the bridge coupling assembly is fabricated or otherwise formed as a unitary design. All such variations and modifications are to be considered within the scope of the present invention the nature of which is to be determined from the foregoing description.

Claims

1 . A rail tensor comprising:

a pair of opposing tie members at one end connected to the first grip member; a pair of opposing tensioning members at one end operatively coupled to the second grip member;

a first coupling configured to bridge the rail member on said one side of the weld joint, said first coupling connected to an opposite end of the pair of tie members; a second coupling configured to bridge the rail member on the opposite side of the weld joint, said second coupling coupled to an opposite end of the pair of tensioning members;

2. A rail tensor as claimed in claim 1 wherein the first and/or second coupling includes a bridge member adapted to transversely bridge the rail member, and a pair of posts rigidly mounted to the bridge member at or adjacent its opposing ends whereby said posts are positioned in a substantially vertical disposition either side of the rail member.

3. A rail tensor as claimed in claim 2 wherein said coupling includes a mounting bracket rigidly secured to each of the posts, the mounting bracket arranged to provide anchorage for one of the linkage members and either one of the tensioning members or one of the tie members.

4. A rail tensor as claimed in claim 3 wherein the mounting brackets are each configured relative to the posts to provide anchorage of the linkage members more distant from one another relative to the lateral spacing of the tie members and/or tensioning members.

5. A rail tensor as claimed in any one of claims 2 to 4 wherein each of the mounting brackets includes an upper and a lower plate rigidly connected to and vertically spaced along the post, said plates being shaped to separate anchorage of the linkage member and including two aligned pairs of openings.

6. A rail tensor as claimed in claim 5 wherein each of the pair of openings is designed to retractably receive a coupling pin for anchoring one of the linkage members and either one of the tensioning or tie members.

7. A rail tensor as claimed in either of claims 5 or 6 wherein one of the pair of openings providing anchorage for the linkage member has a greater lateral spacing from the rail member relative to the other pair of openings providing anchorage for either the tie member or the tensioning member.

8. A rail tensor as claimed in any one of the preceding claims wherein the first grip member and/or the second grip member includes a pair of opposing jaws adapted to grip the rail member. More preferably

9. A rail tensor as claimed in claim 8 wherein the pair of opposing jaws are interconnected by a crossbar which extends transversely across the rail member.

10. A rail tensor as claimed in either of claims 8 or 9 wherein the jaws are each in the form of a cam member pivotally coupled to the crossbar for gripping of the rail member.

1 1 . A rail tensor as claimed in any one of claims 8 to 10 wherein the pair of opposing tensioning members each includes a hydraulically actuated cylinder including a cylinder housing anchored to one of either the first or the second pair of jaws, and a piston rod anchored to the second coupling.

12. A rail tensor as claimed in any one of the preceding claims wherein the rail member is associated with plinth style sleepers.