WO2020249981A1

WO2020249981A1 - An improved rail clamp

Info

Publication number: WO2020249981A1
Application number: PCT/GB2020/051443
Authority: WO
Inventors: Ian Dixon
Original assignee: Codiun Limited
Priority date: 2019-06-14
Filing date: 2020-06-15
Publication date: 2020-12-17
Also published as: GB201908570D0

Abstract

A clamp (10) to secure adjacent rails (50) suitable for carrying a train or the like together is disclosed, the rail being joined by a fish plate (51a, 51b). The clamp comprises a base plate (11) to support either or both rails. The clamp comprises a jaw block (12) which is releasably secured to a first end of the base plate (11), the jaw block having a pressure surface to engage a fish plate. The base plate further includes a locating aperture (17) defined by the base plate to partially house a second jaw block (13), the second jaw block being movable between a first non-engaging position and a second position engaging a fish plate on the opposite side of the rail. Moving means are provided to urge the second jaw block from the non-engaging to the rail-engaging position.

Description

An Improved Rail Clamp

Field of the Invention

The present invention relates to a rail clamp for use in temporarily repairing a rail line. The clamp is intended to hold two rail sections together and is especially, although not exclusively for use in a slab track installation.

Background to the Invention

In the construction of a rail track, the rails being laid down need to be supported to ensure that they do not move due to the weight of the trains passing over them. The ground on which they are laid therefore need to be specially prepared to minimise movement. The primary means to support the rails is that of employing a ballast material formed of a stone material. The rails are secured to sleepers which themselves rest on the ballast. The advantage of using this method is that it is relatively inexpensive to lay the track. However, maintenance needs to be undertaken on a relatively frequent basis to ensure that the ballast has not moved. Moreover, as trains become faster, there is a risk of lighter particles being sucked up in the air stream caused by the trains passage and being deposited onto the rails. The ballast typically needs to be treated to prevent this from happening, thereby increasing its cost.

An alternative therefore is to support the rails on slabs of concrete: often referred to as a slab track. Although this costs more to install, the costs can be recouped in the long term as the inspection and maintenance costs are lower.

One disadvantage of the use of a slab track is when repairs need to be carried out on the track, particularly where the repair involves the joint between adjacent rails. Additionally, monitoring of a joint is made more problematic as monitoring is often carried out by means of monitors included in a clamp installed about the joint. In slab track installations a limited clearance exists between the rail foot and the concrete slab which makes the installation of existing designs of rail repair clamps impossible without disturbing the concrete bed.

Nevertheless, a requirement exists for a temporary clamp system for use in slab track installations. The invention disclosed herein is not only capable of providing a clamping performance similar to existing clamp systems but also overcomes the difficulties posed by the limited space envelope available below the rails.

The rail clamp as herein described is a temporary rail repair clamp including a high tensile steel base plate allowing use of the clamp in both slab track and ballasted track installations. The clamp design can be utilised with practically every combination of rail and fish plate. The clamp is so designed to prevent damage occurring even if the clamp is abused by over tightening. Moreover in certain embodiments, the clamp is constructed of materials which are more malleable than those used in prior art clamps to reduce the risk of fracturing of the clamp if, for example, too much torque is used in tightening the clamp into position.

In particular, the clamp is able to be used in restricted areas such as in slab track installations whilst applying the maximum amount of the bolt tension to the fish plates without risk of bending the bolts.

Summary of the Invention

According to a first aspect of the invention there is provided a clamp to secure adjacent rails suitable for carrying a train or the like together, a rail being joined by a fish plate, the clamp comprising a base plate to support either or both rails; a jaw block releasably secured to a first end of the base plate, the jaw block having a pressure surface to engage a fish plate, the base plate further including a locating aperture defined by the base plate to receive house a second jaw block, the second jaw block being movable within the aperture between a first non engaging position and a second rail-engaging position engaging a fish plate on the opposite side of a rail; moving means to urge the second jaw block from the non-engaging to the rail-engaging position.

Optionally, the base plate is generally rectangular in shape. Further optionally, the central region of the base plate, across the narrow side of the rectangle is broader than at the edge regions to distribute better stress within the base plate.

Preferably, the base plate includes one or more throughapertures linking the locating aperture with an outer edge of the base plate to house the moving means. A throughaperture further preferably has a threaded wall to threadably house a bolt or the like, actuation of the bolt bringing the bolt into engagement with the second jaw block to urge the jaw block against a fish plate.

The second jaw block is of complementary shape to surface features of the edge of the locating aperture, the complementary shape and the surface features inter-engaging when the second jaw block is in the rail-engaging position to prevent the second jaw block from moving out of the aperture. The surface features further preferably comprise a step arrangement.

Brief Description of the Drawings

The invention is now described with respect to the accompanying drawings which show by way of example only, one embodiment of a clamp. In the drawings:

Figures 1 a - 1 c show the components of a clamp;

Figure 2 illustrates a partially-assembled clamp; Figures 3a - 3e are, respectively, a bottom view, side view, top view, top perspective view, and end view of a second embodiment of the base plate of a clamp;

Figure 4 is a perspective view of a first jaw block;

Figure 5 is a perspective view of a second jaw block;

Figure 6 is a perspective view illustrating a clamp in position about a rail section;

Figure 7 is a side view illustrating a clamp in position about a rail section;

Figure 8 illustrates insertion of a base section of a partially-assembled clamp into position relative to a rail;

Figure 9 illustrates positioning of a pressure surface of a clamp against a fish plate;

Figure 10 illustrates positioning of a removable block into position;

Figure 11 illustrates pushing of a removable block against a fish plate; and Figure 12 shows tightening of the screws to secure the clamp.

Description of the Invention

The complete clamp assembly includes a main section and a moveable section. The clamp system consists of two main parts, a fixed jaw and base plate assembly plus a removable jaw. The removable jaw is hooked into place during installation and tightened against the fish plate of the repair assembly by socket head cap screws fitted in the ends of the base plate.

The clamp has typical physical characteristics as follows:

Clamp Thickness 65 mm

Shipping Weight 11.3 kg

Shipping Dimensions 341 x 120 x 108 mm Bolt (std.) M16 grade 12.9

Bolt Head (std.) 12mm Hex Socket

Clamp Bolt Torque 240 Nm In more detail and referring initially to Figures 1 - 7, a clamp is illustrated. The clamp is assembled from three main components: a base plate 11, a first jaw block 12 and a second jaw block 13. In use, the base plate 11 is located beneath the rail to which the clamp is attached, whilst the jaw blocks 1 , 13 sit either side of the rail and push against the rail in clamping engagement.

The base plate 1 1 is generally rectangular in shape, but with its central region widened in the direction of the short axis to impart greater strength, and in particular reduce flexing, to the base plate 11 which supports the rail. At a first end 14 of the base plate 11 are provided throughapertures 15b, here four in number, although other numbers of apertures can be provided if desired. The throughapertures 15b have an internal thread to threadably receive clamp bolts 16. The clamp bolts 16 are threadably housed in throughapertures 15a in the first jaw block 12 and are screwed into the throughapertures 15b, engaging threads on the internal surface of the throughapertures 15b in the base plate 1 1, whereby they act to secure the first jaw block 12 to the base plate 11.

In the region of the second end of the base plate 11, a large locating slot 17 is provided to receive and retain the second jaw block 13. The slot is adapted to engage the second jaw block to prevent unwanted movement, out of the plane of the base plate 11, of the second jaw block 13 out of the slot 17, and is shaped to engage a corresponding configuration of the second jaw block 13. In the hereindisclosed embodiment, the slot 17 has along an edge, a stepped configuration 18. The stepped configuration 18 conforms to the shape of a lower shelf 19 on the extension 20 of the second jaw block 13. Additionally, the undersurface 21 of the shelf 19 has a chamfered configuration. The engagement between the shelf 19 and the stepped configuration 18 prevents the second jaw block 13 from being forced out of the slot 17 and also aligns the second jaw block 13 such that it properly interacts with the rail when the clamp is operated.

In the embodiment of Figures 1, two throughapertures link an end edge 30 of the base plate 11 with the internal edge 31 of the slot 17. The internal edge 31 is chosen to be opposite the stepped configuration 18. The throughapertures are threaded allowing clamp bolts 32 to be screwed into the throughapertures. The free ends of the bolts 32 protrude from the throughapertures, as they are further screwed in, and the bolts 32 eventually push against the rear surface 33 of the extension 20, urging the second jaw block 13 towards the first jaw block 12. The second jaw block is also urged towards the stepped configuration 18 until the shelf 19 and the stepped configuration interengage, securing the second jaw block 13 from falling out of the locating slot 17. In this manner, when in position, the pressure surfaces 34, 35 on the heads of the jaw blocks 12, 13 are pressed against the fish plates joining the rails.

It will be recognised that the number of bolts used to push against the second jaw block 13 can be varied and in the embodiment of base plate 40 in Figures 3, only one bolt, with a single corresponding throughaperture 41 is provided.

The function of the jaw blocks 12, 13 in the hereindescribed embodiment is as described in International (PCT) patent application of number PCT/GB2016/050236 and the jaw blocks 12, 13 act in the same manner as described therein in being urged in use against fish plates joining the two rails together.

A partially-assembled clamp 10 comprising the base plate 11 and the first jaw block 12 of the assembled clamp is fitted to the rail 50 first. The base plate 11 is made of high tensile steel and the jaw blocks 12, 13 are profiled from S355 steel plate with a machined finish for accuracy of fitment. The bolts 32, are proprietary grade 12.9 socket head cap screws and are chosen for the clamp screws to take advantage of the slightly smaller head diameter and to help emphasise the requirement to use a specific application tool. Care should be taken when tightening a bolt as this may cause damage to the bolt thread, the socket head or even the clamp itself. Such damage may be hard to spot and may lead to failure of the thread or the clam at a later time.

The base plate 11 passes under the rail 50 which is secured together by fish plates 51a, 51 b. This continues until the pressure surface 34 on the jaw block 12 touches the fish plate 51 a. The jaw block 13 shown in Figure 1b locks into the slot 17 in the base plate 11 and is pressed against the second fish plate 51 b by the clamp bolts 32. The pressure surfaces 34, 35 of the jaw blocks 12, 13 press against the fish plates 51a, 51 b to secure them, the toe features 22, 23 of the jaw block 12, 13 rest on the upper surface of the rail foot. The clamp bolts 32 are tightened to 240Nm to clamp the fish plates 51a, 51 b to the rail section 50 and complete the installation. To effect a secure temporary rail joint at least two clamps and two compatible fish plates are required. The fish plates must be fitted to the rail across the joint and one clamp assembly must be fitted on either side of the joint as described herein.

Fitting further pairs of clamps increases the security of the joint and users are directed to the local rail authority certification for approved configurations.

A clamp is fitted to the rail 50 as described with reference to Figures 8 - 12. Here, fitment is shown to a rail/sleeper arrangement. First, referring to Figure 8, the fish plates 51a, 51b are fitted to either side of the rail web with the middle of the fish plate adjacent to the rail joint. A partially-assembled clamp 10 is prepared and is fitted so that the base plate 11 passes below the rail foot and the toe feature 52, 53 of the jaw blocks 12, 13 rest on the top surface of the rail foot 54. In bullhead rail applications the toe feature does not engage with the rail.

In Figure 9, it can be seen that the toe feature 52, 53 of a clamp rests on the foot of the rail. Placing the pressure surface against the fish plate, hooks the block over the edge of the rail foot. Figure 10 shows the removable block being lowered onto the plate and hooked in place. With the clamp bolts 32 wound back, the moveable section is offered up so that the toe feature 53 locks with the lower shelf 19 on the base plate 1 1. A check should be made that the second jaw block 13 is correctly seated on the base plate 1 1.

Turning to Figure 11, the second jaw block 13 is pushed into position to engage the jaw block 13 with the base plate 11 in that the second jaw block 13 is pushed up to the fish plate 51 b and the clamp bolts 32 screwed up by hand to take up the slack. The clamp bolts 32 are then tightened one at a time to 120Nm to the fish plate 51b and then to 240Nm to complete the installation.

Factors such as thermal expansion and contraction of the components, breakdown of scale and debris on the fish plate and rail surfaces and vibration from passing trains can slacken the clamps in service. Where the clamp is to remain in situ for extended periods it is recommended that the tightness of the clamp bolts is checked every seven days or more frequently if they are repeatedly found to have loosened.

As an example of how to check the torque, a vertical mark (at 12 o'clock position) is made with chalk on the bolt's head. The bolts are undone by one quarter to one half turn. The bolts are re-torqued to 240Nm and the position of the chalk mark examined. If the mark is between the 11 o'clock and 1 o'clock positions, then this indicates that the clamp and fish plate assembly is fully bedded-in and the maintenance intervals may be extended. If the mark has moved further, then this indicates that the clamp and fish plate assembly is not yet stable and maintenance periods should be reduced.

Removal of the clamp is the reverse of the installation procedure. The clamp bolts are loosened and the jaw block 13 removed.

The partially-assembled clamp 10 is slid out from beneath the rail. Where the clamp has been left in position for a long period it may be stuck in position by corrosion - in this case simply tapping the sections should release them: advisably with a copper or soft-faced hammer for this operation.

Once the clamp is free of the rail, the jaw block 13 is refitted and the clamp bolts lightly tightened to ensure the parts are kept together in storage. The clamp is used to clamp standard fish plates to rails and a wide variety of rail and fish plate combinations are suitable for fixing by different embodiments of the clamp. These include but are not limited to:

Catalogue Number Description Supplier Code Manufacturer

1131b Flat Bottom Rail

57/054263 CEN56E1 4 Hole 6mm Gap MJ1030 LB Foster / Coronet

57/054281 CEN56E1 4 Hole Tight Joint LB Foster / Coronet

57/054031 CEN56E1 Dimple Maintenance Plate MJ1032 LB Foster / Coronet 57/054031 1 13Lb Emergency Straight Fish plate Henry Williams

57/054029 1 131b Emergency Joggled Fish plate Henry Williams

57/054263 BS1 13A Standard 4 Hole Joint Fish plate Acieries et Lamnoirs de Rives

57/054281 BS1 13A Standard 4 Hole Tight Joint Fish Acieries et Lamnoirs de Rives plate

UIC54 Section 56E1 Emergency Straight Fish plate 1200mm Long Acieries et Lamnoirs de Rives (ALR)

UIC60 / CEN60 Rail

57/054035 CEN 60E2 4 Hole 6mm Gap MJ1007 LB Foster / Coronet

57/060539 CEN 60E2 4 Hole Tight Joint MJ1008 LB Foster / Coronet

57/60101 UIC60 Emergency Joggled Fish plate Henry Williams

57/054035 CEN60 4 Hole 6mm Gap Fish plate Acieries et Lamnoires de Rives

57/060539 CEN60 4 Hole Tight Joint Fish plate Acieries et Lamnoires de Rives

57/060543 CEN60 6 Hole Tight Joint Fish plate Acieries et Lamnoires de Rives

57/060540 CEN60 New— 1131b New 6 Hole Fish plate Henry Williams

57/060541 CEN60 New - 1 131b 3mm Worn 6 HoleCorus

Fish plate

57/060542 CEN60 New - 1 131b 6mm Worn 6 HoleCorus

Fish plate

Claims

1. A damp to secure adjacent rails suitable for carrying a train or the like together, a rail being joined by a fish plate, the clamp comprising a base plate to support either or both rails;

a jaw block releasably secured to a first end of the base plate, the jaw block having a pressure surface to engage a fish plate, the base plate including a locating aperture defined by the base plate to receive a second jaw block, the second jaw block being movable within the aperture between a first non engaging position and a second position engaging a fish plate on the opposite side of a rail; moving means to urge the second jaw block from the non-engaging to the rail-engaging position.

2. A clamp according to Claim 1, wherein the base plate is generally rectangular in shape.

3. A clamp according to Claim 2, wherein the central region of the base plate, across the narrow side of the rectangle is broader than at the edge regions.

4. A clamp according to any preceding claim, wherein the base plate includes one or more throughapertures linking an internal surface of the locating aperture with an outer edge of the base plate to house the moving means.

5. A clamp according to Claim 4, wherein the or each throughaperture as a threaded wall to threadably house a bolt or the like, actuation of the bolt bringing the bolt into engagement with the second jaw block to urge the jaw block against a fish plate.

6. A clamp according to any preceding claim, wherein the second jaw block is of complementary shape to surface features of the edge of the locating aperture, the complementary shape and the surface features inter-engaging when the second jaw block is in the rail-engaging position to prevent the second jaw block from moving out of the aperture.

7. A clamp according to Claim 6, wherein the surface features comprise a stepped arrangement.

8. A base plate, the base plate being generally rectangular and including a locating aperture defined by the base plate to receive a second jaw block the base plate including one or more throughapertures linking the internal surface of the locating aperture with an outer edge of the base plate.

9. A base plate according to claim 8, wherein the central region of the base plate, across the narrow side of the rectangle is broader than at the edge regions.

10. A base plate according to claim 8 or claim 9, wherein the locating aperture includes a stepped configuration on the internal surface of the locating aperture, said stepped configuration being located on the opposite side of the locating aperture to the throughapertures.