EP1473408A1

EP1473408A1 - A device and method for removing a rail clip

Info

Publication number: EP1473408A1
Application number: EP04252383A
Authority: EP
Inventors: Paul Sheldon
Original assignee: RWE Innogy PLC
Current assignee: RWE Generation UK PLC
Priority date: 2003-04-30
Filing date: 2004-04-23
Publication date: 2004-11-03

Abstract

A method for removing a clip securing a rail to a sleeper from a clip housing (4) by drilling out substantially only the portion of the clip retained within the clip housing (4).

Description

The present invention relates to a drill for removing a clip securing a rail to a sleeper and a corresponding method.
Such clips are generally known in the art as Pandrol™ clips. These are used to secure a railway rail to a sleeper.
For each sleeper, four clip housings are embedded, one on each side of a pair of rails which run across the sleeper. A clip is inserted as an interference fit into each housing such that a portion of the clip is an interference fit over the base of the rail thereby clamping the rail onto the sleeper.
When the clip is to be removed to allow a rail to be replaced, this is generally done by knocking or hydraulically pushing the clip out of the housing. There are occasions, however, where the clip becomes stuck in the housing and cannot easily be removed. In these circumstances, the current practice is to remove the entire housing and clip from the sleeper. This is done firstly by removing the head (i.e. the non-imbedded part) of the housing, and subsequently drilling down through the sleeper to remove the remains of the housing. A new housing is then set into an epoxy resin within the drilled hole and left to cure for one to two hours before a new clip is inserted into the housing. This is a particularly time consuming process, and the present invention aims to improve this.
According to the present invention there is provided a method for removing a clip securing a rail to a sleeper from a clip housing by drilling out substantially only the portion of the clip retained within the clip housing.
By drilling out only a portion of the clip retained within the clip housing, rather than drilling out the entire housing, the present invention provides a vastly simplified way of removing a stuck or seized clip. In particular, once the clip has been drilled out, it can simply be replaced by a new clip in the same way that the non-stuck clip can be replaced, and there is no need to replace any part of the clip housing.
The method preferably comprises clamping a drill with respect to the clip, and aligning the drill with the portion of the clip to be drilled. The rail provides a stable way to support the drill with respect to the clip, and the rail is also generally aligned with the portion of the clip retained within the clip housing. Alternatively, the drill could be clamped to the sleeper or to some other rigid structure in the vicinity of the clip.
According to a second aspect of the present invention there is provided a drill for drilling into a clip housing to remove a clip securing a rail to a sleeper, and the drill comprising a drill bit for drilling substantially only into the part of the clip which is retained in the housing and a clamp for clamping the drill to the rail, the relationship between the drill bit and the clamp being such that, in use, when the clamp is clamped to the rail, the drill bit is aligned with the part of the clip housing in which the clip is retained.
The drill may have a means to advance the drill along the rail to carry out the drilling process. However, preferably, the drill has means to advance the drill bit with respect to the clamp to carry out the drilling process.
Preferably, the drill has a mechanism for adjusting the axis of the drill bit. The mechanism may adjust the position of the drill with respect to the clamp. However, preferably, the mechanism is provided to adjust the position of the clamp on the rail. The mechanism can preferably translate the drilling axis to allow the drill bit to be shifted into alignment with the part of the clip housing in which the clip is retained. The mechanism preferably also allows rotation of the drilling axis at least in the horizontal plane in case the part of the clip housing in which the clip is retained is not parallel to the rail. In order to provide full adjustability, it is also preferable for the mechanism to be able to rotate the drilling axis in the vertical plane.
The drill may be powered to rotate by any source of motive power, such as an electrical motor, hydraulic motor or internal combustion engine. For convenience, however, it is preferable that the power source is mounted to the drill.
The same or a separate power source may be used to advance the drill bit. Further, the apparatus also preferably comprises a manual mechanism for advancing the drill bit. This manual mechanism is useful when setting up the drill to bring the drill bit into alignment with the part of the clip housing in which the clip is retained.
An example of a method and drill will now be described with reference to the accompanying drawings which is a perspective view of the drill.
A preferred embodiment of the drill 1 is shown. The drill 1 is secured to a railway rail 2 having a central web 3 at the general location of a clip and clip housing 4.
The drill comprises a clamping assembly 5 securing the drilling apparatus 1 to the rail 2 by horizontal alignment grub screws 7, which pass through both sides of the clamping unit 5, and by vertical alignment grub screws 11 which pass through a top side 13 of the clamping unit 5. The clamping assembly 5 has an inverted U form which locates over the top of the rail 2. In the preferred embodiment shown in Figure 1, the top side 13 and a second side 19 are integrated into one L-shaped component. The first side 9 is bolted to this L-shaped component. The sides 9,19 and the top surface 13 of the clamping assembly 5 are typically constructed from steel plate of a thickness of approximately 15mm.
Once located over the rail 2 the clamping assembly 5 is secured to the rail 2 by horizontal alignment grub screws 7 which contact the central web 3 of the rail 2. Similarly, the vertical alignment screws 11 are adjusted to contact the top surface of the rail 2.
In addition to securing the clamping assembly 5 to the rail, screws 7, 11 aid with alignment of the drilling rig 1 with the 1 housing 4. By screwing each of the screws 7,11 to a greater or lesser degree through the first side 9 or the top surface 13 the alignment of the clamping assembly with the rail can be altered.
A slideway assembly 17 is attached to the second side 19 of the clamping assembly. The slideway assembly 17 comprises a fixed slideway 15 and a movable slideway 21 which slides on rails 22 on the fixed slideway. The fixed slideway 15 is attached to vertical side 19 of the clamping assembly 5 by any suitable means. In the preferred embodiment the fixed slideway 15 is retained by a number of horizontal bolts (not shown). The length of the fixed slideway 15 must be sufficient to enable the movable slideway 21 to allow the tip of the drilling spindle to be first moved up to the housing and then to pass through the housing.
The movable slideway 21 is moved in relation to the fixed slideway 15 via a lead screw (not shown) passing through a threaded portion at the rear of the slideway 21. The lead screw may be driven by a motor or by a manual feed 35 in the form of a rotatable wheel. Generally the manual feed 35 is used to move the cutting tip up to the housing and the machine feed via a gearbox is used to ensure even drilling.
Attached to the movable slideway 21 is a drive assembly 23. In the preferred embodiment the power source for the drilling operation is provided by a motor 24, linked to a horizontal spindle holder 29 by a gearbox 25. The gearbox 25 contains a bevel gear arrangement allowing the motor to be mounted vertically. This provides greater access and visibility to the drill tip. Also, the motor can be increased in size without affecting this access. It is envisaged that power may be supplied by an alternative form of electric motor, by an hydraulic motor or by an internal combustion engine.
The spindle holder 29 retains the drilling spindle 31 which is used to drill out the clip (not shown) from the housing 4. The drilling spindle 31 is provided with a tip, the diameter of which is sized to match the diameter of the clip. In the embodiment of Figure 1 the drilling spindle is preferably a Maxcut™ holder (Ref: 220105-003m) into which 20 mm Maxcut™ inserts (Ref: M124540 2240)are inserted.
The clamping unit 5 is preferably detachable from the slideway assembly to enable the clamping unit 5 to be changed according to the type of rail to which it will be fitted.
It will be appreciated that the drill is arranged such that the drilling spindle is mounted lowermost on the drill. This allows sufficient clearance for the drilling spindle to be positioned close enough to the ground to be aligned with the clip. Also, the drill must be configured to fit between clips on adjacent sleepers without obstruction.
When a railway engineer comes across a clip which cannot be knocked out in the conventional manner, the drill of the present invention is brought into use. Firstly, the clamping unit 5 is attached to the rail with the drilling spindle 31 roughly adjacent to the housing. The geometry of the drill is such that when the clamping unit is placed on the rail, the axis of the spindle 31 will be approximately in alignment with the part of the clip which is within the housing 4. Fine adjustments are made using the screws 7,11 which allow both translation of the axis of the spindle 31 in vertical and horizontal directions, and also tilting of the axis in both the horizontal and vertical directions. When the spindle 31 is aligned, the manual feed 35 is used to advance the spindle 31 to be directly adjacent to the clip. The motor 24 is then started up to rotate the spindle 31, and the spindle is advanced either manually or by a motor to drill out the portion of the clip from within the housing 4. Once this is done, the drill is retracted.
The drilling process thus removes the portion of the clip which is stuck or seized in the housing, and cuts this away from the remainder of the clip which falls away. What remains is the housing 4 which is in the same state as it would have been had the clip simply been knocked out, i.e. it is ready to receive a new clip. The screws 7,11 of the clamping unit are then backed off allowing the drill to be removed from the rail.

Claims

A method for removing a clip securing a rail to a sleeper from a clip housing by drilling out substantially only the portion of the clip retained within the clip housing.
A method according to claim 1, further comprising clamping a drill with respect to the clip and aligning the drill with the portion of the clip to be drilled.
A method according to claim 2, further comprising clamping the drill to the rail.
A drill for drilling into a clip housing to remove a clip securing a rail to a sleeper, the drill comprising a drill bit for drilling substantially only into the part of the clip which is retained in the housing and a clamp for clamping the drill to the rail, the relationship between the drill bit and clamp being such that, in use, when the clamp is clamped to a rail, the drill bit is aligned with the part of the clip housing in which the clip is retained.
A drill according to claim 4, further comprising means to advance the drill bit with respect to the clamp to carry out the drilling process.
A drill according to claim 4 or 5, wherein the drill has a mechanism for adjusting the position of the axis of the drill bit.
A drill according to claim 6, wherein the mechanism for adjusting the position of the axis of the drill bit is provided to adjust the position of the clamp on the rail.
A drill according to claim 6 or claim 7, wherein the mechanism is arranged to translate the drilling axis to allow the drill bit to be shifted into alignment with the part of the clip housing in which the clip is retained.
A drill according to any one of claims 6 to 8, wherein the mechanism is arranged to allow rotation of the drilling axis in the horizontal plane.
A mechanism according to claims 6 to 9, wherein the mechanism is arranged to allow rotation of the drilling axis in the vertical plane.
A drill according to any one of claims 4 to 10, wherein a power source to rotate the drill bit is mounted to the drill.
A drill according to any one of claims 4 to 11, further comprising a manual mechanism for advancing the drill bit.