EP0027838A1

EP0027838A1 - A rail fastener

Info

Publication number: EP0027838A1
Application number: EP79302350A
Authority: EP
Inventors: Hartley Frank Young
Original assignee: Ralph McKay Ltd
Current assignee: Ralph McKay Ltd
Priority date: 1979-07-05
Filing date: 1979-10-26
Publication date: 1981-05-06
Also published as: ZA803926B; SU1033009A3; DE3067127D1; DE2965802D1; EP0027838B1; MY8700210A

Abstract

A rail fastening clip comprises a plate blank bent over itself to provide a base portion (7) adapted to be fixed relative to a rail sleeper and two arms (8) the free ends (9) of which are adjacent the base portion to seat on the foot of a rail. The arms (8) are tapered in cross-section from the base (7) towards their free ends to improve the deflection range of the clip. A method of forming the clip from a generally U-shaped flat metal blank is described.

Description

This invention relates to a rail fastening clip, comprising a U-shaped member having a base portion adapted to be fixed relative to a rail sleeper and to a method of producing such fasteners.
Many types of rail fastening clips have been proposed for fastening rails to sleepers. One proposal has been to use a clip comprising a U-shaped drawn wire which is bent over itself to form a clip having two parallel arms of equal diameter which terminate adjacent the base of the said "U". In this construction the base of the U fits within a clip holder housing secured to a sleeper and the free ends of said clip lie on the foot of the rail clamping the rail to the sleeper.
In clamping such clips to the rail deflection of the free ends must occur. The clips defined above have a maximum working deflection of about 11 mm and in many cases where misalignment between the rail, sleeper and clip holder occurs difficulty in fitting the clip may be experienced. However, the greatest difficulty met is that where there is misalignment, unacceptable variations in the clamping force of the clip on the rail can occur. The , deflection of the clips should be uniform and when the deflection range is small a misalignment can easily lead to a large variation from the norm.
To overcome this problem the present invention as claimed is a rail clip comprising a U-shaped member in which the arms of the U are bent to bring the free ends adjacent the base of the U and said arms are tapered in cross-section from the base of the U toward the free ends.
The term 'tapering' is meant to include any progressive reduction in the cross-sectional dimensions of the arms. For example, instead of uniform tapering, the outer edges of the arms may be parallel with the inner edges diverging to provide all of the tapering required.
It is not necessary for the tapering to extend the full length of the arms to obtain an improved deflection range for the clip. By improving the deflection range of the clip any misalignments will have a smaller effect on the clamping force and any variations will be within acceptable limits.
Another aspect of this invention relates to a method of forming rail clips of the general kind referred to above as well as the particular clip according to the present invention.
Generally rail clips are formed from drawn rods which are bent to a U-shape and then bent to the clip form. The forming techniques required as well as the starting material itself, result in an overall expensive method of making the clips.
To overcome this problem the method of the present invention comprises supplying plate material, blanking said plate to form a U-shaped blank and forming the blank into a rail clip in which the free ends of the U lie adjacent the base of said U.
By using plate metal to form the strips and by blanking the basic U-shape a less expensive means of forming rail clips results and the rail clips have the same quality as those produced by present day conventional methods.
Where clips of this kind have been blanked from plate material the edges are often rough. It has been discovered that in areas of high stress fractures of the clips can be started from small cracks or irregularities in the edges of the clips. Thus to reduce the occurrence of fatigue and fractures in rail clips formed by blanking the clips from metal plate the edges of the blanked out clip corresponding to those edges of the finished clip which are subject to high stress are preferably coined.
The coining operation provides a smooth edge surface adjacent the high stress points and eliminates the possibility of a fracture commencing from a rough edge portion.
The invention may be carried out in the manner described in detail in the following with reference to the accompanying drawings, in which :-

Figure 1 is a plan view of a rail clip according to a first embodiment;
Figure 2 is a side view of the clip shown in Figure l;
Figure 3 is a plan of a blank from which the rail clips can be formed;
Figures 4 and 5 illustrate a rail clip according to a second embodiment of this invention;
Figure 6 is a sectional view of a rail clip as shown in Figure 1 in conjunction with a rail and sleeper.

The clip of Figures 1 and 2 comprises a base section 7 from which the tapered arms 8 extend in an arc and terminate in free ends 9 which extend toward the base section 7.
Figures 4 and 5 illustrate a similar type clip having a base section 11 tapered arms 12 which arc towards the base section 11. The tapered arms 12 terminate in free ends 13 which extend away from the base section 11.
The clips of Figures 1 and 2 or Figures 4 and 5 can be manufactured from the blank illustrated in Figure 3. The blank is 'U'-shaped comprising a base 15 and arms 16 which can be bent into the shape shown in Figures 1 and 2 and Figures 4 and 5.
Figure 6 illustrates a sectional view of a sleeper 20 and a rail 21 having a rail foot 22. Clipholder 23, secured to the sleeper 20, includes a recess 25 into which the base section 7 of the clip shown in Figures 1 and 2 fits. The clipholder 23 includes a clip 26 over which the free ends 9 of the rail clip must pass to clamp onto the rail foot 22. Thus the lip 26 assists in deflecting the free ends 9 of the clip in relation to the base section 7.
The deflection which can occur in practice with the two rail clips illustrated in Figures 1, 2, 4 and 5 is of the order of 15 mm and thus both clips can be used where large deflections of the rail clips are needed to fasten the rail to the sleeper.
When the rail clip is in position as shown in Figure 6 any deflection of the free ends 9 relative to the base section 7 will result in major stress occurring in the internal portions 29 of the arms 8 of the clips and the base.section 7. To avoid the likelihood of such stresses causing fractures the internal edge portions 29 are coined particularly in those portions of greatest curvature. Generally it is only necessary to coin the internal edges 29. However, it is of some value to also coin the corresponding outer edges 30.
The coining operation is preferably carried out between the blanking and forming operations. The edges to be treated are ground with an appropriate tool to coin the edges and eliminate surface deformations.
In its preferred form the method of the present invention uses metal plate in strip form which is fed to a blanking press where a blank is formed. Figure 3 illustrates a blank for use in forming rail clips of the kind shown in Figures 1,2, 4 and 5. However, the present process is equally applicable to forming clips where the cross-sectional dimensions for the arms is constant. The cross-sectional dimensions of the final clip are determined by the shape of the initial blank.
Following blanking the two dimensional blank is heated to below 1100°C formed into its three dimensional form as shown in Figures 1, 2, 4 and 5. The product is then reheated to within the range of 820°C to 900°C and then quenched. Subsequent to quenching the clips are tempered in a tempering furnace to desired Rockwell hardness and are then allowed to cool prior to packing.
In its two aspects this invention provides a rail clip which is more versatile in its application than previously proposed clips and also a cost saving method of forming both conventional rail clips and clips of this invention.

Claims

1. A rail fastening clip comprising a U-shaped member having a base portion adapted to be fixed relative to a rail sleeper and the arms are bent to bring the free ends of the U-shaped member adjacent the base of the U-section for seating on the foot of a rail, characterised in that said arms (8, 12) are tapered in cross-section from the base (7, 11) of the U toward the free ends (9, 13) of said arms.

2. A rail clip as claimed in Claim 1, wherein said U-shaped member is formed from plate material (15).

3. A method of forming a rail fastening clip characterised by supplying metal plate to a blanking press to form a generally U-shaped flat blank (15) in which the arms (16) of the U taper from the base toward the free ends of said arms, and bending the U to bring the free ends (9, 13) of the arms adjacent said base (7, 11) of the U-shaped member such that said base portion is adapted to be secured to a rail sleeper and said free ends are adapted to seat on the foot of a rail.

4. A rail clip as claimed in Claim 2 wherein the inner curved edges (29) of said arms are coined. t

1. A rail fastening clip adapted for fastening a rail (21) to an associated sleeper (20), said clip comprising a U-shaped member formed from metal plate having a base (7, 11) and two substantially uniformly tapered arms (8, 12) extending therefrom, each of said arms being substantially uniformly tapered over substantially its entire length, said base (7, 11) adapted to be secured to said sleeper outwardly spaced from the foot (22) of said rail, said arms (8, 12) being bent inwardly beyond said base and oriented for contact with the foot (22) of said rail such that said arms are deflected upwardly relative to said rail (21) to develop downward clamping forces tending to hold said rail on said sleeper (20).

2. A rail clip as claimed in Claim 1, wherein the inner curved edges (29) of said arms are coined.

3. A method of forming a rail fastening clip characterised by supplying metal plate to a blanking press to form a generally U-shaped flat blank (15) in which the arms (16) of the U taper from the base toward the free ends of said arms, and bending the U to bring the free ends (9, 13) of the arms adjacent said base (7,11) of the U-shaped member such that said base portion is adapted to be secured to a rail sleeper and said free ends are adapted to seat on the foot of a rail.