RAILWAY RAIL FASTENING CLIP AND INSULATOR
The present invention relates to a railway rail fastening clip and insulator.
As shown in Figures 1A, 1B and 1C of the accompanying drawings, WO02/31264A
(GB2384020B/US6923381B) discloses a railway rail fastening clip 3 for fastening a
railway rail to an underlying rail foundation. The clip 3 is formed of an elongate plate
shaped such that a central region 3 1 of the plate has in profile the form of a letter C, a
first end region of the plate extending from one side of the central region 3 1 of the plate
to form a base portion 32 of the clip 3 for engaging a rail fastening anchoring device
secured to the rail foundation and a second end region of the plate extending from the
opposite side of the central region 3 1 of the plate to form a toe portion 33 of the clip 3
for bearing on the railway rail, the toe portion 33 extending further than the base portion
32. The toe portion 33 of the clip 3 is bent so as to have first and second main parts
33A, 33B, the first main part 33A extending a different angle to the second main part
33B. The toe portion 33 is birfurcated, each bifurcated part of the toe portion 33 being
shaped to provide insulator retaining means 34A, 34B for retaining thereon individual
toe insulators (not shown) for electrically insulating the clip 3 from the rail. The base
portion 32 of the clip 3 has an end face 36 connected to an inner face 32A of the base
portion 32 by a slanted face 37, angled at approximately 45° with respect to both the
inner face 32A and the end face 36, which acts as a lead-in chamfer when the base
portion 33 of the clip 3 is being driven into the anchoring device. On the inner face of
the base portion 32, adjacent to the chamfer 37, is a detent 35.
According to an embodiment of the present invention there is provided a railway rail
fastening clip for fastening a railway rail to an underlying rail foundation, which clip is
formed of an elongate plate shaped such that a central region of the plate has in profile
the form of a letter C, a first end region of the plate extending from one side of the
central region of the plate to form a substantially planar base portion of the clip for
engaging a rail fastening anchoring device secured to the rail foundation and a second
end region of the plate extending from the opposite side of the central region of the
plate to form a toe portion of the clip for bearing on a foot of the railway rail, such that in
profile the second end region extends further than the first end region, wherein the toe
portion of the clip is provided with a throughhole which is arranged such that, when the
clip is in its operative configuration, part or all of the throughhole lies above the foot of
the rail, the throughhole being configured to receive a corresponding portion of a toe
insulator for electrically insulating the clip from the rail whereby the insulator can be
retained on the toe portion of the clip. The throughhole may be made by cold-punching
through the plate.
Through its design a clip embodying the present invention may be easier to
manufacture so as to have a consistent geometry, since the throughhole can be
stamped into the plate before the plate is heated and processed to provide the
remaining features of the clip, such as the bends in the plate and a lead-in chamfer on
the free end of the second end region of the plate, and thus the operation of forming
the throughhole and the operation of providing the remaining features of the clip can
have their own respective datum settings.
The throughhole may comprise an elongate slot. The slot may have an approximately
rectangular periphery, having substantially straight long sides and rounded short sides.
Although the clip 3 can be installed simply by pushing the back of the clip 3, it cannot
be removed simply by pushing at the front of the clip 3 , as attempting to do so causes
the clip 3 to bind itself ever more tightly into the anchoring device (shoulder). In
particular, applying a lateral force to the toe portion of a magnitude which would seem
to be sufficient to extract the clip from the shoulder, actually causes the clip to start
opening out and roll about the 'heel' contact between the clip and the shoulder. This
tends to increase the upward vertical force between the shoulder and the other end of
the clip, so locking it ever more tightly into position. It is therefore effectively impossible
to pull the clip out by the toe portion, and certainly impossible to do this with the sort of
loads that can be applied with hand tools or small machines. Even if much larger
forces were applied with larger machines, and the clip were to be removed in this way,
the clip and toe insulators would end up being permanently distorted. Consequently,
the clip 3 has to be pulled out by pins inserted just in front of the central portion 3 1 (rear
arch). This makes hand tools slower to use and more cumbersome than desirable, and
machines more so. Accordingly, it is desirable to provide a railway rail fastening clip
which can be extracted more easily from an anchoring device.
An aspect ratio H/L for a clip embodying the present invention may be < 0.6, H being
the height of the clip in profile defined as the maximum extent of the clip above a plane
containing an outer surface of the base portion and L being the length of the clip in
profile defined as the maximum extent of the clip in a direction parallel to the plane.
A ratio H/h for a clip embodying the present invention may be £ 6.00, H being the
maximum extent of the clip above a plane containing an outer surface of the base
portion and h being the minimum distance between the plane and a point on the
second end region of the clip which is closest to the plane.
In contrast to the prior art clip described above, a clip having an aspect ratio H/L £ 0.6
and/or a ratio H/h < 6.00 can, owing to its side-on geometry, be extracted from a
shoulder much more easily by pulling on the front of the clip, despite the fact that the
contact points between the clip and the shoulder, and the relative positions of these
compared to the toe, are all substantially the same as in the prior art clip.
This improvement is thought to result from an increased stiffness of the lower part of
the clip which is such that, as the force applied at the toe increases, the lower clip
transmits enough of the lateral extraction force component from the toe to the other
end of the bar, where the clip is located and held into the shoulder, that it is able to
disengage before the vertical force builds up to an extent that locks it even more tightly
in place.
It has been found that for such a clip strains on installation are the same or slightly
lower than for the prior art clip, and the load-deflection characteristic is very similar to
that of the prior art clip. A clip having the specified ratio(s) will fit into the existing
shoulder. Although a new tool can be designed to extract the clip more easily, the new
clip is backwardly compatible in that it can be extracted using a slightly modified
version of the existing tool used to pull the prior art clip out by its rear arch.
In a preferred embodiment of the present invention the clip is provided with a rail clip
insulator for electrically insulating the clip from a railway rail, the insulator comprising: a
base; walls extending upwards from the base around some of the periphery of the base
so as to leave an opening along part of the periphery, the base and the walls together
defining an open-topped recess for receiving the toe portion of the clip; and a spigot
extending upwards from the base for retaining the toe portion of the clip within the
recess, wherein the said insulator is arranged on a lower, load bearing surface of the
toe portion of the said clip such that the spigot of the insulator extends through the said
throughhole of the said toe portion.
In contrast to the prior art clip 3, where each toe part is provided with its own insulator
cap which is attached to relatively small features punched in the end of each toe part,
the toe portion of a clip embodying the present invention has a throughhole which can
engage the spigot of an insulator. The loads that are applied to the toe when the clip is
driven on to and off the rail are therefore applied through the spigot that passes
through the clip toe, which provides a more secure connection when the clip is being
extracted than the prior art arrangement.
The spigot of the insulator may be made of deformable material. The spigot may be a
hollow member. The spigot may comprise walls defining the outline of the spigot. The
spigot may be open at its top and/or its bottom. The spigot may be located substantially
centrally on the base of the insulator. The spigot may have an approximately
rectangular outline, having substantially straight long sides and rounded short sides.
In certain circumstances, for example in order to retain the insulator more securely on
the clip toe, a top end of the spigot, which extends upwards beyond the throughhole,
may be shaped such it extends over part of an upper surface of the toe portion
adjacent to the throughhole. The shaping of the toe end of the spigot may be applied
either during manufacture of the insulator or after insertion of the spigot into the
throughhole, for example through the deformation of the top end of the spigot.
Alternatively, after insertion of the spigot into the throughhole, the top end of the spigot
may be provided with a cap member which extends over part of the upper surface of
the toe portion adjacent to the throughhole.
Reference will now be made, by way of example, to the accompanying drawings, in
which:
Figures A, 1B and 1C (described above) show respective side, front and plan views of
a prior art railway rail fastening clip;
Figures 2A, 2B, 2C and 2D show respective perspective, plan, cross-sectional and side
views of a railway rail fastening clip embodying the present invention, Figure 2C
showing a cross-section of the clip taken on line C-C in Figure 2B;
Figure 3A shows a side view of a rail clip embodying the present invention superposed
on a side view of a prior art rail clip, and Figures 3B and 3C show respective side views
of the rail clip embodying the first to fifth aspects of the present invention and the prior
art rail clip;
Figures 4A and 4B show perspective views of a rail clip embodying the present
invention respectively with and without a rail clip insulator, and Figures 4C and 4D
show perspective views of a prior art rail clip respectively with and without rail clip
insulators;
Figures 5A, 5B, 5C, 5D, 5E and 5F show respective perspective, plan, front, side, rear
and cross-sectional views of a rail clip insulator for use with a clip embodying the
present invention, Figure 5F showing a cross-section of the insulator taken on line V-V
in Figure 5B;
Figures 6A and 6B show respective plan and side views of a clip embodying the
present invention to which a rail clip insulator is attached, and Figure 6C shows a
perspective view of a clip embodying the present invention attached to an alternative
rail clip insulator; and
Figures 7A to 7D show respective perspective, side, plan and cross-sectional views of
a clip embodying the present invention, with attached insulator, in its operative
configuration installed in an anchoring device, where Figure 7D is a cross-section on
line D-D in Figure 7C.
As shown in Figures 2A to 2D, a railway rail fastening clip 1 embodying the present
invention, for fastening a railway rail to an underlying rail foundation, is formed of an
elongate plate shaped such that a central region 1 of the plate, forming the rear arch
of the clip 1, has in profile the form of a letter C. A first end region of the plate,
extending from one side of the central region 1 of the plate to a free end 6 , forms a
substantially planar base portion 12 of the clip 1 for engaging a rail fastening anchoring
device secured to the rail foundation. A second end region of the plate, extending from
the opposite side of the central region 1 of the plate to a free end 15, forms a toe
portion 13 of the clip 1 for bearing on the railway rail, such that in profile the second
end region extends further than the first end region. The second end region, forming
the toe portion 3 of the clip , is shaped so as to have first and second main parts,
13A and 13B, and a lower load bearing surface 13C, the first main part 13A extending
from the central region 1 in a first direction and the second main part 13B extending
from the first main part 3A in a second direction different to the first direction.
Branding, identifying the origin of the clip, may be applied to the first main part 13A or
the second main part 13B, and in this position it will be visible when the clip is in use.
The toe portion 3 of the clip is provided with a throughhole configured to receive a
corresponding portion of a toe insulator (not shown in Figures 2A to 2D) for electrically
insulating the clip 1 from the rail whereby the insulator can be retained on the toe
portion 13 of the clip 1. As shown most clearly in Figure 2A, the throughhole 1 is not
open at the free end 15 of the clip . In this embodiment the throughhole 1 comprises
an elongate slot, with an approximately rectangular periphery, having substantially
straight long sides and rounded short sides, but other shapes of throughhole 14 may
be provided. The throughhole 14 is preferably of relatively large area compared to that
of the second main part 3B and may be formed, for example, by cold-punching
through the toe portion (second end region) of the plate, where the stress is low. For
example, if in the clip 3 shown in Figures 2A to 2D the dimension X was 3 1.5mm and
the dimension Y was 77mm, dimension x of the throughhole 14 would be around
12.7mm and dimension y of the throughhole 14 would be around 50.8mm.
As can be seen from the superposed clips 1 and 3 shown in Figure 3A, in certain
embodiments the side-on geometry of the clip 1 differs from the prior art clip 3
described above in various ways, as will now be described with reference to Fig. 3B
which shows the clip 1 and Fig. 3C which shows the prior art clip 3 described above.
As shown in the Figures, H and H' represent the respective heights of the clips 1, 3 in
profile, defined as the maximum extent of the clips 1, 3 above a plane A containing an
outer surface of the base portion 13, 33; L , L' represents the length of the clip 1, 3 in
profile, defined as the maximum extent of the clip 1, 3 in a direction parallel to the plane
A; a, a' is the angle made by the first direction, in which the first main part 13A, 33A of
the second end region extends, with respect to the plane A; b, b' is the angle made by
the second direction, in which the second main part 13B, 33B of the second end region
extends, with respect to the plane A; h , h' is the minimum distance between the plane
A and a point on the second end region of the clip 1, 3 which is closest to the plane A;
and B, B' is the maximum extent of the base portion 12, 32 of the clip 1, 3 from the
outermost edge of the central region 1, 3 1 to the free end of the first end region
measured parallel to the plane A.
In a clip 1 embodying the present invention, which is in an unstressed configuration
(i.e. before installation of the clip in a rail fastening assembly), an aspect ratio H/L for
the clip 1 may be £ 0.6. The aspect ratio H/L may fall within a range from 0.4 to 06, or
more preferably from 0.45 to 0.6, or even more preferably from 0.45 to 0.55. Prior art
clips 3 have a larger aspect ratio H'/L' than such a clip , for example a typical clip 3,
such as shown in Figure 3B, has an aspect ratio H'/L' of 0.64. For the clip 1 shown in
Figure 3A by way of example, H/L is 0.49.
In a clip 1 embodying the present invention, which is in an unstressed configuration
(i.e. before installation of the clip in a rail fastening assembly), the angle a made by the
first direction with respect to the plane A may be < 50°. Angle a may fall within a range
from 20° to 50°, or more preferably from 30° to 50°, or even more preferably from 30° to
40°. Prior art clips 3 have a larger angle a' than such a clip 1, for example a typical clip
3, such as shown in Figure 3B, has an angle a' of 68°. For the clip 1 shown in Figure
3A by way of example, angle a is 35°.
In a clip 1 embodying the present invention, which is in an unstressed configuration
(i.e. before installation of the clip in a rail fastening assembly), a ratio H/h for the clip 1
may be £ 6.00. The ratio H/h may fall within a range from 3.00 to 6.00, or more
preferably from 4.00 to 6.00, or even more preferably from 4.00 to 5.00. Prior art clips
3 have a larger ratio H7h' than such a clip 1, for example a typical clip 3, such as
shown in Figure 3B, has a ratio H'/h' of 7.4. For the clip 1 shown in Figure 3A by way
of example, ratio H/h is 4.6.
In such configurations the clip is easier to extract from a shoulder and to install therein
than a prior art clip such as the clip 3 . For example, the extraction force required to
remove a typical clip, such as the example clip 1 shown in Figure 3A, from a shoulder
was found to be 18.95kN, whereas an extraction force of 37.65kN was unable to
remove the clip 3 from the same shoulder. Similarly, the installation force required to
drive a typical clip, such as the example clip 1 shown in Figure 3A, into the shoulder
was found to be 13.55kN as compared to an installation force of 26.79kN required to
drive the clip 3 into the same shoulder.
For the clip 1 shown in Figure 3A by way of example, length B is 6 .5mm and angle b
is 14.5°, whereas for the clip 3 shown in Figure 3B length B' is 59mm and angle b' is
18.5°.
By way of example, other dimensions shown in Fig. 3A may be as follows: length
a=9Smm, length b=67mm and length c=51mm; diameter D=33mm; radius of curvature
r=14mm; and angle g=15°.
As can be seen by comparing the clip 1 shown in Figures 4B with the clip 3 shown in
Figure 4D, unlike the toe portion 33 of the clip 3, the toe portion 13 of the clip 1 is not
bifurcated, nor does it have the same sort of insulator-retaining features 34A, 34B as
the clip 3 for retaining toe insulators 40A, 40B as shown in Figure 4C. Instead the toe
portion 13 of the clip 1 is provided, in the second main part 13B, with a throughhole 4
in the form of a slot which, as shown in Figure 4A, can receive part of a rail clip
insulator 2 for electrically insulating a railway rail fastening clip from a railway rail. The
insulator 2 is shown in more detail in Figures 5A to 5F. Further views of the insulator 2
attached to the toe of the clip 3 are shown in Figures 6A and 6B, and Figure 6C which
shows an alternative embodiment.
The insulator 2 comprises a base 2 1 and walls 22 extending upwards from the base 2 1
around some of the periphery of the base 2 1 so as to leave an opening 23 along part of
the periphery. The base 2 1 and the walls 22 together define an open-topped recess 24
for receiving the toe portion 13 of the clip 1, in particular for receiving the second main
part 13B. A spigot 25 is located substantially centrally on the base 2 1 and extends
upwards from the base 2 1 for retaining the toe portion 13 of the clip 1 within the recess
24. The top of the spigot 25 extends above the walls 22. When in use the insulator 2
is arranged on the lower, load bearing surface 13C of the toe portion 13 of the clip 1
such that the spigot 25 of the insulator 2 extends through the said throughhole 14 of
the toe portion 13 .
Like the throughhole 14, the spigot 25 has an approximately rectangular outline, having
substantially straight long sides and rounded short sides. In this embodiment the
spigot 25 is made of deformable material and is shaped and sized relative to the
throughhole 4 so as to have an interference/mechanical fit therewith which acts to
retain the insulator on the toe portion of the clip. In some circumstances, for example
to provide a more secure fit on the clip 1 during transportation and/or where the spigot
25 is made of non-deformable material and/or is not shaped and sized so as to have an
interference fit with the throughhole 14, a top end of the spigot 25, which extends
upwards beyond the throughhole 14, may be adapted to extend over part of an upper
surface of the toe portion 3 adjacent to the throughhole 14, such that the spigot 25
cannot pull back through. For example, the top end of the spigot 25 may be shaped
during manufacture so as to have a snap-fit design (for example, an outwardlyextending
deformable annular lip, not shown), or re-shaped (not shown) after the spigot
25 has been inserted into the throughhole 14 (for example by ultrasonic staking).
Alternatively, after insertion into the throughhole 14, the top end of the spigot 25 may
be fitted (for example, by welding) with a cap member 26, as shown in Figure 6C, the
periphery of which extends beyond the periphery of the throughhole 14.
Although not essential, to save material, and/or to facilitate ultrasonic or other means of
assembly, it is desirable if the spigot 25 is a hollow, or partly hollow (as in this
embodiment), member, comprising walls 25A defining the outline of the spigot 25,
which is open at its top. Although not shown in this example, the spigot may also be
open at its bottom. As mentioned above, and shown in Figure 6C, the open end of the
spigot 25 may be covered with a cap member 26.
As shown in Figures 7A to 7D, particularly Figure 7C, when the clip 1 is in its operative
configuration, fully installed in an anchoring device 50 and bearing on a rail 100 such
that the insulator 2 is in contact with a foot 101 of the rail, part but not all of the
throughhole 4 of the clip 1 lies over the rail foot 101 . In particular, whilst part of the
periphery 140 of the throughhole 14, when viewed from above the rail 100, extends
beyond the outer edge 103 of the rail foot 101 , the remaining part of the throughhole
periphery 140 extends over the rail foot 101 . It should be noted, however, that in some
embodiments all parts of the periphery 140 of the throughhole 14 may extend over the
rail foot.
Claims
. A railway rail fastening clip (1) for fastening a railway rail (100) to an underlying
rail foundation, which clip (1) is formed of an elongate plate shaped such that a central
region ( 1 ) of the plate has in profile the form of a letter C, a first end region of the plate
extending from one side of the central region ( 11) of the plate to form a substantially
planar base portion (12) of the clip ( 1) for engaging a rail fastening anchoring device
(50) secured to the rail foundation and a second end region of the plate extending from
the opposite side of the central region ( ) of the plate to form a toe portion ( 3) of the
clip ( 1 ) for bearing on a foot (101 ) of the railway rail (100), such that in profile the
second end region extends further than the first end region, characterised in that the
toe portion ( 3) of the clip (1) is provided with a throughhole (14) which is arranged
such that, when the clip ( 1) is in its operative configuration, part or all of the
throughhole (14) lies above the foot (101) of the rail, the throughhole (14) being
configured to receive a corresponding portion of a toe insulator (2) for electrically
insulating the clip ( 1) from the rail (100) whereby the insulator (2) can be retained on
the toe portion ( 13) of the clip ( 1) .
2. A clip as claimed in claim 1, wherein the throughhole (14) comprises an elongate
slot.
3 . A clip as claimed in claim 2 , wherein the slot has an approximately rectangular
periphery, having substantially straight long sides and rounded short sides.
4 . A clip as claimed in claim 1, 2 or 3, wherein an aspect ratio H/L for the clip ( 1) is £
0.6, H being the height of the clip (1) in profile defined as the maximum extent of the
clip ( 1 ) above a plane containing an outer surface of the base portion and L being the
length of the clip (1) in profile defined as the maximum extent of the clip (1) in a
direction parallel to the plane.
5 . A clip as claimed in any preceding claim, wherein a ratio H/h for the clip (1) is <
6.00, H being the maximum extent of the clip (1) above a plane containing an outer
surface of the base portion (12) and h being the minimum distance between the plane
and a point on the second end region of the clip (1) which is closest to the plane.
6. A clip as claimed in any preceding claim in combination with a rail clip insulator
(2) for electrically insulating the clip (1) from a railway rail (100), the insulator (2)
comprising: a base (21 ) ; walls (22) extending upwards from the base (21) around some
of the periphery of the base (21 ) so as to leave an opening (23) along part of the
periphery, the base (21) and the walls (22) together defining an open-topped recess
(24) for receiving the toe portion (13) of the clip (1); and a spigot (25) extending
upwards from the base (21) for retaining the toe portion (13) of the clip (1) within the
recess (24), wherein the said insulator (2) is arranged on a lower, load bearing surface
(13C) of the toe portion (13) of the said clip (1) such that the spigot (25) of the insulator
(2) extends through the said throughhole ( 14) of the said toe portion ( 13).
7 . A clip and insulator combination as claimed in claim 6, wherein the spigot (25) is
made of deformable material.
8. A clip and insulator combination as claimed in claim 6 or 7, wherein the spigot
(25) is a hollow member.
9 . A clip and insulator combination as claimed in claim 6, 7 or 8, wherein the spigot
(25) comprises spigot walls (25A) defining the outline of the spigot (25).
10. A clip and insulator combination as claimed in claim 8 or 9, wherein the spigot
(25) is open at its top and/or its bottom.
. A clip and insulator combination as claimed in any one of claims 6 to 10, wherein
the spigot (25) is located substantially centrally on the base (21 ) .
12. A clip and insulator combination as claimed in any of claims 6 to 1, wherein the
spigot (25) has an approximately rectangular outline, having substantially straight long
sides and rounded short sides.
13. A clip and insulator combination as claimed in any one of claims 6 to 12, wherein
a top end of the spigot (25), which extends upwards beyond the throughhole (14), is
shaped such that it extends over part of an upper surface of the toe portion (13)
adjacent to the throughhole ( ).
14. A clip and insulator combination as claimed in any one of claims 6 to 12, wherein
a top end of the spigot (25), which extends upwards beyond the throughhole (14), is
provided with a cap member (26) which extends over part of an upper surface of the
toe portion (13) adjacent to the throughhole (14).