GB2201626A - Extracting device - Google Patents

Abstract

There is disclosed a device for extracting ferrules from rail carrying chairs comprising a ferrule-engaging head 50, a radially extending flange 70 and a rod extending from the flange away from the head. The head 50 includes teeth 52, 55, 58, 61 diminishing in diameter and effective to bite into the ferrule. The diameter and length of the head 50 being such that, after the head 50 has been accommodated inside the ferrule, displacement of the rod transversely of its longitudinal axis causes displacement of he head 50 whereby one side thereof bites into the ferrule with the aid of its teeth and the opposite side of the flange 70 bears as a pivot on the surface of the chair. The ferrule is pulled up and out of the hole of the chair as displacement of the rod continues. The rod is attached to the flange 70 via a stub 80 which is integral with the flange 70 which in turn is integral with the head 50. The flange and stub are made of heat toughened carbon steel. <IMAGE>

Description

EXTRACTING DEVICE The present invention relates to railway lines and to the refixing of screw-spikes which have become loose in the sleeper.

Many wooden sleepers have the rails secured to them via metal chairs which are attached . to the sleepers by screw-spikes which are threaded spikes screwed into pre-drilled undersize holes in the sleepers. The screw-spikes pass through an oversize tapered hole in the chair in which fits a tapered plastic or wooden sleeve (called a ferrule) which when first inserted is slightly longer than the hole is deep. The underside of the head of the screw-spike thus bears against the free top end of the ferrule.

The ferrule cushions the spike and chair assembly against shock. The sleepers rest on ballast and with the passage of trains of varying weight and length travelling at various speeds the loads vary widely and in time cause displacement of the ballast. It is not known whether this causes or is sole cause of loosening of the screw-spikes but in time the screw-spikes come out of the sleeper.

In order to refix the screw-spike tightly it is first unscrewed from the hole. The condition of the hole is then assessed with a gauge to determine whether the hole can be reused. In many instances the hole may have become worn but can be reused by use of a spiral aluminium alloy insert, which we sell under the mark VORTOK (Registered Trade Mark). The use of such inserts is described and claimed in our GB published specification Serial No. 2163510 and pending GB Patent Application No. 8531731, Serial No. ......... .

During regular maintenance of the track the screwspikes are tightened in the chairs and the ferrule is gradually compressed down into the hole in the chair.

When it no longer protrudes above the top surface of the chair it can no longer serve its purpose and has to be removed and replaced. The removal however is difficult and so far no really satisfactory solution to the problem has been devised.

The metal chairs are made of cast iron and the inside surface of the hole is thus rough. The ferrule whilst initially being an easy fit in the hole with time becomes moulded to this rough surface and despite the taper is very difficult to pull out. A variety of lever devices with moving parts and without have been tried out but none are sufficiently robust to be any better than the use of a pointed crow-bar which is used to smash up the ferrule.

What is desired is something which easily and rapidly will extract the ferrule but from which the used ferrule can readily be removed. A corkscrew type of device is unsatisfactory because the ferrule is difficult to remove from it.

According to the present invention a device for extracting ferrules from rail carrying chairs comprises a ferrule-engaging head, a radially extending flange and a rod extending from the flange away from the head, the ferrule-engaging head diminishing in diameter at positions spaced axially from the flange and being provided with configurations effective to bite into the ferrule, the diameter and length of the head being arranged to be such that on displacing the axis of the head (by means of the rod used as a lever) from a central position co-axial with the chair hole to a position inclined to the axis, one side of the head bites into the ferrule and the opposite side of the flange bears on the surface of the chair and affords a pivot, such that the ferrule is pulled up the hole, the dimensions of the head and the flange being related to that of the hole and the external profile of the chair in such a way that continued leverage in the same or in other directions causes the flange to ride out over the surface of the chair and the ferrule to be drawn up out of the hole without the ferrule-engaging head interfering with the hole.

The head is of a diameter less than the inside diameter of the ferrule in an unused condition at least when inserted therein from the wider end of the ferrule. This has the beneficial effect that after the ferrule is removed from the hole and is jammed at an angle on the head it may be readily freed by tilting it back to a position co-axial with the head and then slid off. The head may be made ferrule-engaging by being provided with circumferential grooves and these may be of the same angle and pitch or may preferably have an angle more nearly axial as they approach the free end of the head. These grooves are preferably located on the bottom half of the head, the top half being a plain cylindrical untapered surface.The grooves may be such as to afford three, four or five outwardly facing circumferential teeth which are preferably sharp rather than rounded so as to bite into the ferrule.

One preferred form has one, two or three symmetrical grooves affording symmetrical teeth having an apex angle of about 60-80 followed by one, two or three asymmetrical grooves affording assymmetrical teeth at the free end of the head. These teeth may have the same or similar apex angles but have upper shoulders (nearer the flange) at an angle to the axis of 10-30 and a lower shoulder at right angles to the axis. Preferably there are two shoulders of each type, the diameter of the outer edge of the teeth decreasing from the flange to the free end. As one preferred embodiment the diameter of the cylindrical half or shank of the head is 24.5mm; that of the first tooth 23.5mm; that of the second tooth 22.0mm (these both being symmetrical); that of the third being 18.Omm and that of the fourth being 9.6mm (these both being asymmetrical).More broadly the ratio of the shank to the first tooth may be 1:0.98 to 1:0.93, preferably 1:0.97 to 1:0.94 e.g. 1:0.96, for the second tooth the ratio may be 1:0.92 to 1:0.86 preferably 1:0.91 to 1:0.87 e.g. 1:0.90, for the third tooth the ratio may be 1:0.85 to 1:0.54 preferably 1:0.80 to 1:0.60 e.g.

1:0.73 and for the fourth tooth the ratio may be 1:0.50 to 1:0.35 preferably 1:0.45 to 1:0.35 e.g. 1:0.39.

The diameter of the flange in one preferred embodiment is 50.8mm i.e. the ratio of the diameter of the shank of the head to that of the flange is 1:2.07.

More broadly this ratio may be 1:1.5 to 1:3.0 preferably 1:1.75 to 1:2.5.

The rod is preferably attached to the flange via a stub which is integral with the flange which in turn is integral with the head. The rod is preferably co-axial with the head. It may surround the stub or be located in a socket in the stub. It may be a rod or a tube.

It is desirably of electrically non conducting material e.g. of fibreglass e.g. 11/8 to 11/4 inches in diameter (2.9 to 3.2cm) and about 3 feet (0.9m) long to facilitate easy leverage without need for the user to bend.

The head, flange and stub are preferably made of heat-toughened carbon steel.

Instead of grooves the head may be provided with individual teeth or nubs preferably evenly spaced around the head and extending to radial distances from the axis conforming with the teaching already given in respect of the circumferential teeth.

The invention may be put into practice in various ways and one specific embodiment will be described by way of example with reference to the accompanying drawings in which: Figure 1 shows a newly fitted ferrule in position in a chair with the screw-spike wound home; Figure 2 shows the metal head and part of the rod of an extracting tool in accordance with the present invention in side elevation; and Figures 3A, 3B, 3C and 3D show four exemplary stages in the removal of a compressed ferrule from a chair using the extracting tool shown in Figure 2.

Figure 1 shows a chair 10 having a rounded form of shoulder 11 resting on a wooden sleeper 35, these both being shown as scrap sections.

A screw-spike 20 passes through a tapered ferrule 30 which is received in a tapered hole 12 in the chair.

The screw-spike 20 has a square head 21, a plain tapered shank 23 and a tapered threaded portion 24 carrying a thread 25 which has a root 22 between the threads. This root may be flat or curved. The arrangement shown in Figure 1 is of a newly fitted rail screw-spike and ferrule. The ferrule is first inserted in the hole 12 and the screw-spike inserted through the ferrule and then screwed down tightly against the top of the ferrule. With time and routine tightening of the screw-spike during track maintenance the ferrule is compressed into the hole as shown in Figure 3A. At

this stage or earlier a new ferruletand a VORTOK spiral member may need to be inserted. In order to insert a new ferrule or a spiral member the old ferrule has to be removed.

Figure 2 shows a tool in accordance with the present invention for achieving this. The tool has a ferrule engaging head 50, a radially extending flange 70 and a rod securing stub 80 having an axial cavity 81 in which is tightly fitted a fibre glass rod 90 which is 3 feet (0.9 metres) long and 11/8 or 11/4 inches in diameter.

The head flange and stub are integral and made of heat toughened carbon steel.

The head has a cylindrical shank 51 and two symmetrical circumferential teeth 52 and 55 and two asymmetrical teeth 58 and 61. The length of the shank and the diameter and axial distance of the teeth from the flange are designed to be such that the head will not snag on the walls of the hole 12 in the chair while being levered from the hole as shown in the sequence of Figures 3A to 3D. A different form of chair is shown in Figure 3 namely one having a sharp or square shoulder rather than a rounded one. In addition for simplicity the stub and rod have been shown as a single item.

It will be appreciated that the chairs are not cast with precision and that there are variations in the exact dimensions and shapes of the chairs. In addition the casting leaves a rough surface to the hole in which the ferrule is located. Moreover there are many designs of chair to suit various forms of rail clip and screw spikes. However the concept of the teeth tapering in towards the axis together with the flange 20 sliding down over the shoulder 12 of the chair is one which can readily be applied to produce sizes of tools to fit the dimensions of chairs which will be encountered on any given length of track.

In addition waggling of the tool through relatively small angles can be used to achieve a degree of preliminary loosening before the actual levering out of the ferrule from the hole.

The circumferential teeth are of a size such as to bite significantly into the ferrule and give a good grip. As can be seen in Figure 3B the ferrule is in effect gripped between the teeth and the wall of the hole over which it slides during at least part of the levering movement. Moreover the tapering of the diameters of the teeth in addition to avoiding the tool snagging on the hole also facilitate removal of the ferrule from the tool after it has been removed from the hole. Thus it is merely necessary to push the ferrule back from its canted position relative to the tool as shown in Figure 3D to its original aligned position as shown in Figure 3A and then pull it off the tool.

Figure 2 is diagrammatic so far as the teeth are concerned and the teeth are more accurately shown in Figure 3. The teeth have straight sided flanks and their dimensions are as follows: Axial length of shank 51, 18mms; Axial length from end 53 of shank 18 to crest 54 of tooth 52, 6.6mms; Axial length from crest 54 to crest 56 of tooth 55, 6.6mms; Axial length from crest 56 to crest 57 of tooth 58, 6.6mms; Axial length from crest 57 to crest (and end) 59 of tooth 61, 3.2mms.

The upper and lower flanks fo the teeth 52 and 55 are at the same angles to the axis of the head, namely about 500. The upper flanks of the teeth 57 and 61 are at the same angle, namely about 150, to the axis of the head and at a different angle to the lower flanks which are both at right angles to the axis of the head.

The diameter of the shank 51 is 24.5mms; that of the crest 54 is 23.5mms; that of the crest 56 is 22.Omms; that of the crest 57 is 18mms; and that of crest 59 is 9.6mms, whilst that of flange 20 is 50.8mms.

Dimensions of this order are thought likely to be effective but clearly adjustment to suit particular chairs and ferrules may be necessary and is permissable within the scope of the present invention.

Claims (13)

1. A device for extracting ferrules from rail carrying chairs comprising a ferrule-engaging head, a radially extending flange and a rod extending from the flange away from the head, the ferrule-engaging head diminishing in diameter at positions spaced axially from the flange and being provided with configurations effective to bite into the ferrule, the diameter and length of the head being arranged to be such that on displacing the axis of the head (by means of the rod used as a lever) from a central position co-axial with the chair hole to a position inclined to the axis, one side of the head bites into the ferrule and the opposite side of the flange bears on the surface of the chair and affords a pivot, such that the ferrule is pulled up the hole, the dimensions of the head and the flange being related to that of the hole and the external profile of the chair in such a way that continued leverage in the same or in other directions causes the flange to ride out over the surface of the chair and the ferrule to be drawn up out of the hole without the ferrule-engaging head interfering with the hole.

2. A device as claimed in Claim 1 in which the head is of a diameter less than the inside diameter of the ferrule in an unused condition at least when inserted therein from the wider end of the ferrule.

3. A device as claimed in Claim 1 or Claim 2 in which the head of the device is made ferrule-engaging by being provided with circumferential grooves affording outwardly facing teeth.

4. A device as claimed in Claim 3 in which the teeth are of varying angle and pitch and have an angle more nearly axial as they approach the free end of the head.

5. A device as claimed in Claim 3 or Claim 4 in which the grooves are located on the bottom portion of the head, the top portion being a plain cylindrical untapered surface.

6. A device as claimed in Claim 3, 4 or 5 which has one, two or three symmetrical grooves affording symmetrical teeth having an apex angle of about 60-80 followed by one, two or three asymmetrical grooves affording assymmetrical teeth at the free end of the head.

7. A device as claimed in Claim 3, 4, 5 or 6 provided with as symmetrical teeth at the free end of the head which have the same or similar apex angles but have upper shoulders (nearer the flange) at an angle to the axis of 10-30 and a lower shoulder at right angles to the axis.

8. A device as claimed in Claim 6 or Claim 7 in which there are two shoulders of each type, the diameter of the outer edge of the teeth decreasing from the flange to the free end.

9. A device as claimed in any one of Claims 1 to 8 in which the ratio of the shank to the first tooth is 1:0.98 to 1:0.93, and for the second tooth the ratio is 1:0.92 to 1:0.86 and for the third tooth the ratio is 1:0.85 to 1:0.54 and for the fourth tooth the ratio is 1:0.50 to 1:0.35.

10. A device as claimed in any one of Claims 1 to 9 in which the ratio of the diameter of the shank of the head to that of the flange is 1:1.5 to 1:3.0.

11. A device as claimed in any one of Claims 1 to 10 in which the rod is attached to the flange via a stub which is integral with the flange which in turn is integral with the head.

12. A device as claimed in Claim 1 substantially as specifically described herein with reference to Figure 2.

13. A device as claimed in any one of the preceeding claims whether provided with the rod or not.