ZA200602116B - Rail clip and rail-sleeper fastener - Google Patents

Description

BACKGROUND OF THE INVENTION

[0001] This invention relates generally to the fixing of a rail to a sleeper.

[0002] Typically a sleeper is forsmed from a prestressed cast elongate cementitious body which includes suitable formations to receive transversely extending rails. The rails are clamped to the sleeper, at the time of installation, using rail clips of any appropriate type. In many respects existing sleepers and clips are satisfactowy. However there are two significant disadvantages of currently used sys tems.

[0003] In the first place the rail clips, which normally are made from a tensile steel, can be detached from the sleepers and rails with which they are engaged, with relative ease. The clips therefore form targets for thieves who steel the clips for their scrap metal walue.

[0004] A second disadvantage arises in that when the sleepers are shipped from a factory, at which the sleepe-rs are made, the clips are normally either loosely attached to the sleepers or are separately shipped. In either instance there is a likelihood that the clips can be lost or, again, that the clips will form easy targets for theft.

SUMMARY OF INVENTION

[0005] It is an object of the irwvention to address the aforementioned problems at least partly.

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[0006] in the first instance the inverstion provides a rail clip which includes a substantially U-shaped member which is made from a resilient material and which has a base and two limbs which extend from the base, each limb including a respective locating formaation at a position which is between the base and a free end of the limb, and wherein the limbs, viewed from one side, are in line with each other and include respective sections between the base and the free end of each limb which are transversely displaced from a plane in which an extremity of the base and thme free ends of the limbs lie.

[0007] Preferably the base is arcuate, viewed in plan (i.e. substantially at a 100 right angle to the aforementioned side view).

[0008] Each locating formation maay be in the form of a projection or a groove, according to requirement.

[0009] The invention provides, secondly, a sleeper which includes an elongate cementitious body whicha has at least two rail-pad receiving formations at spaced locations on ar upper surface of the body, a plurality of shoulders which are partly embeddezd in the body with the shoulders being positioned, in pairs, on opposed respective sides of each of the rail-pad receiving formations, each shoulder including a U-shaped section which is located above the upper surface of the body, and at least one locating formation in the U-shaped section.

[0010] Preferably each U-shaped sesction has at least two locating formations which oppose each other.

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[0011] The invention further extends to a rail-sleeper fastening which includes a sleeper which has an elongate cementitious body and at least one

U-shaped shoulder which is partly embedded in the body and which has a U- shaped section which is located above an upper surface of the body, a rail which extends transversely to the body and which is engaged with a pad positioned on the upper surface of the body, and a rail clip formed, at least, from a U-shaped member which has a basse which overlies a flange of the rail, and two limbs, which depend from the Base, which extend through the U- shaped section, and wherein the base hass a larger transverse dimension than the U-shaped section so that the base cannot pass through the U-shaped section.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The invention is further described by way of example with reference to the accompanying drawings in which:

Figure 1 is a cross sectional side view, taken transversely to the direction in which an elongate rail extends, of a raill-sleeper fastening according to the invention;

Figure 2 is a plan view of the rail-sleeper Fastening of Figure 1;

Figure 3 in an enlarged plan view of a c lip which is engaged with a sleeper, depicting movement of the clip relatively teo the sleeper; and

Figure 4 is a cross sectional side and fexont view respectively of a shoulder used in the fastening of the invention.

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DESCRIPTION OF PREFERRED EMBODIMENT

[0013] Figures 1 and 2 of the accompanying drawings illustrate in cross section and plan respectively a rail-sleeper fasstening 10 according to the invention which includes a rail 12, a sleeper 14, clips 16 and 18 respectively and shoulders 20 and 22.

[0014] The rail 12 is conventional and includess a tread section 24, a base flange 26 and a centrally positioned web 28 which extends upwardly from the flange.

[0015] The sleeper 14 comprises an elongate precast cementitious body 32 in an upper surface 34 of which are formed a number of rail pad receiving formations 36. There is one formation 36 for each rail which crosses, and which is to be supported by, the sleeper.

[0016] A rail pad 38, of conventional construction, is positioned inside each respective formation 36 and forms a shaped upwardly facing recess 40 into which the flange 26 fits neatly.

[0017] The shoulders 20 and 22 are identical to each other. Figure 4 shows a shoulder 22 in cross section from one side, arad from the front, respectively.

Each shoulder has a base 42 and two elongate lambs 44 and 46 which project, spaced from one another, from the base. A locating plate 50 is secured between the limbs 44 and 46. A principal function of the plate is to ensure that the limbs are precisely embedded, to a goredetermined extent, in the

P.20588/es cementitious body 32 of the sleeper so that a relatively small U-shaped section 54 of defined proportions, projects upwardly from thea upper surface 34 of thes body 32. Another function of the plate is to provide aa reaction surface for a rail clip, as is described hereinafter.

[0018] Portions 44A and 46A of the respective limbs, included in the U- shap ed section 54, have respective vertically extending grooves 44B and 46B in op posed inwardly facing surfaces 44C and 46C.

[0019] The rail clips 16 and 18 are engaged with the respe ctive shoulders 20 and 22. The rail clips are identical and consequently the construction of the rail clip 18 only is described hereinafter. Figure 3 illustrates in plan the rail clip 18 om an enlarged scale.

[0020] The rail clip 18 is made from an elongate strip of spring steel and is inherently resilient. It includes a base 62 which, viewed in pl an, is substantially arcuate. Elongate limbs 64 and 66 respectively extend from the base. The limbs, in plan (see Figure 3), are mirror images of eacha other. Each limb incllades an indented section 66, an outwardly bulging section 68 and a porti on 70 which tapers inwardly (towards the opposing limbo) from the section 68, towards a respective free end 72. At an outermost extremity (viewed in plan) each limb, on the bulging section 68, has a respective projection 74.

[0021] The base 62 has a maximum transverse dimersion 76 which is slightly more than the maximum transverse dimension 78 of the U-shaped sect ion 54 of the shoulder.

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[0022] The clip 18 is made from spring steel and it is possible, using a suitable tool or implement, to urge the limbs 64 and 66 slightly towards each other. This process does not however materially affect the transverse dimension 7 6 of the base. Viewed from a side (see Figure 1) the limbs 64 and 66 of & clip are essentially in line with each other and are similarly shaped. Referring to the clip 18 (in Figure 1) each limb exteznds upwardly from the bas e 62 and has a rounded upper bulge 80, at a central location, and a portion 82 which extends downwardly to the free end 72. An under surface 86 of the lim b, near its free end, is flat and is shaped so that it can bear firmly against an u pper surface of the plate 50.

[0023] The sleeper is formed under factory conditions usirg techniques which are kmown in the art. At the time of manufacture of the sleeper the shoulders 20 and 22 are embedded at defined locations, fixed by means of suitable jigs (not shown), in the body 32. Once the cementitious body has set the clips 16 and 18 are engaged with the respective shoulders. This is accomplishead in the absence of the rail 12. Each clip is positiored so that the base 62 is nore or less above the formation 36 and so that the free ends 72 of the limbs 64 and 66 can be pushed, using a suitable tool, through the U- shaped sect ion 54 in the direction of an arrow 90, see Figure 3. The limbs 64 and 66 are initially forced towards each other, using a suitable tool, so that the projections 74 on the outer sides of the limbs can be movesd passed the correspondirg groove 44B and 46B on the inner surfaces of the U-shaped section 54, to the dotted line positions shown in Figure 3. The clips are thereby securely fixed to the shoulders and the sleeper togethe r with the clips

P 20588/jes can be shipped to a user. Preferably the clips are not shipped separately from the sleeper.

[0024] At a site of use the sleeper is installed on ballast, not shown, using techniques which are known in the art and which are therefore are not further described herein. The rail pads 38 are then engaged with the respective formations 36 and, when appropriate, the rails 12 are engaged with the rail pads. The clips 16 and 18 at this stage, are sufficiently far apart from each other to allow the flange 26 of each rail to pass without hindrance between the clips and come to rest on the rail pad.

[0025] Insulators 92 which are made from suitable electrically insulating material, are then positioned on opposed sides of the flange 26 adjacent the clips 16 and 18.

[0026] Use is then m ade of a suitable tool, not shown, which forces the limbs of each clip towards each other. Thereafter each clip is moved towards the web 28 i.e. in the direction of an arrow 96, see Figure 3, until the projections 74 are moved into emgagement with the respective grooves 44B and 46B in the U-shaped section 54.

[0027] As the base 62 of a clip strikes the corresponding insulator 92 substantial force must be exerted on the clip to ensure that it is moved further towards the web 28. Typically the clearance between the flange 26 and the base 62 is of the order of 3mm, and the insulator’'s thickness is about 5mm.

This means that the toase 62 must be deflected upwardly, at least by 2mm, in

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. | | Page 9 order for the base to be movexd to a position at which it overlies a substantial portion of the insulator and, consequently, so that the base then lies securely over the corresponding portion of the flange.

[0028] Figure 1 shows that the clip 18 is deflected upwardly, adjacent the base 62, in the direction of an arrow 98. The bulging portion 80 of the clip abuts an inner surface of the base 42 of the U-shaped section while the flat underside 86 of each limb, adjacent the respective free end thereof, bears squarely and firmly against thes plate 50.

[0029] The clips exerts substantial force on the rail and ensure that it is firmly fixed to the sleeper. The geometrical arrangement is such that with each clip in the Figure 2 position, the clip is frictionally and mechanically engaged with the corresponding section 54 of the respective shoulder which projects above the upper surface of the sleeper. The base 62 exerts a force, generated by the distortion of the tensile exlement from which the clip is made, which acts downwardly on the flange forcing it towards the rail pad.

[0030] Figure 3 shows the clip 18 in operative (solid line) and retracted (dotted line) positions. As the transverse dimension 76 of the base is greater than the maximum transvers<e dimension 78 of the U-shaped section 54 it is not possible for the base to be moved through the U-shaped section 54. Thus for all practical purposes thes clip is immovably locked to the corresponding shoulder.

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[0031] If a clip is moved to the maximum possible extent away from the rail and towards the shoulder a stage is reached at which the base does not overlie the flange and it is therefore possi ble for the rail to be lifted free from the rail pad. At this point the clip can be nmoved in the reverse direction, i.e. in the direction 96, and if the clip is moved sufficiently far the clip can then be completely disengaged from the shoulder.

[0032] The clip of the invention is, as noted, preferably supplied as a component which is integrally associated with the sleeper. This facilitates transport and stock control of the compon ents. On the other hand once a rail has been engaged with a sleeper it is not possible for the clips to be detached from the sleeper, unless the rail is first removed from the sleeper. This feature substantially reduces the prospect that the clips will be stolen.

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Claims (8)

CLAIMS . pa €

1. A rail clip which includes a substantially U-shaped member wrhich is made from a resilient material and which has a base and two limbs which extend fr<om the base, each limb including a respective «cating formation at a poosition which is between the base and a free end of the limb, and whherein the limbs, viewed from one side, are in li ne with each other and include respective sections between the base and the free end of eaci limb which are transversely displaced from a plane in which an extrenmnity of the base and the free ends of the limbs lie.

2. A rail clip acco rding to claim 1 wherein the base, viewed in plan, is arcuate.

3. A rail clip accor ding to claim 1 or 2 wherein each locating formation is a projection.

4. A rail clip which is made from an elongate piece of resilient nmaterial and which inclu des an arcuate base and two limbs which exterd from the base, each limb including an indented section, an ou-twardly bulging section , a portion which tapers, towards the opposing limb, from the bulgirmg section towards a free end of the limb, and a projection on the bulging section.

5. A sleeper which includes an elongate cementitious body which has at least two rail-poad receiving formations at spaced locations on an P 20588/jes oo oo Page 12 upper surface of the body, a plurality of shoulders which are partly embedded in the body with the shoulder s being positioned, in pairs, on opposed respective sides of each: of the rail-pad receiving formations, each shoulder including a U-shaped section which is located above the upper surface of the bosdy, and at least one locating formation in the U-shaped section.

6. A sleeper according to claim 5 wherein each U-shaped section has at least two locating formations which oppos-e each other.

7. A rail-sleeper fastening which includes a sleeper which has an elongate cementitious body and at least one U-shaped shoulder which is partly embedded in the body and which has a U-shaped section which is located above an upper surface of the body, a rail which extends transversely to the body and which is engaged with a pad positioned on the upper surface of the body, and a rail clip formed, at least, from a U-shaped memioer which has a base which overlies a flange of the rail, and two linmbs, which depend from the base, which extend through the U-shaped section, and wherein the base has a larger transverse dimension tihan the U-shaped section so that the base cannot pass through the U-shaped section.

8. A rail sleeper fastening which includes a sleeper, U-shaped shoulders on the sleeper, a rail which extends tramsversely to the sleeper, and two clips which are engaged with the shoulders to retain the rail P 20588/jes

. . | Page 13 engaged with the sleeper and which: are disengageable from the shoulders only if the rail is disengaged ¥rom the sleeper. Dated this 13" day of March 2006. = McCALLUM, RADEMEYER & FREIMOND Patent Agents for the Applicant

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