Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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Correoted ~heet
1 [Engll~ pa~inatlon]
A DEVICE ~OR FASTE~N~ A TRACN RAIL ON A T~E
The pre~n~ inventlon rel~te~ to a device for
fa~t~nin~ ~ tra~k rail on a tie or "s~eeper".
In gene~al, device~ of this type comprise i~
particular firstly a flexlble support pad place~ on the
load-beariny ~urf~ce of the tie and on whi~h ~he base of
the ra~l re~ts, and ~e~ ly ~ide clips oon~itut~a by
~prlng~, each $n the form of loop~, ea~h kept pr~s~ed
a~ain~ ~h~ rail by ~aving one of its br~nches eng~ged ln
an insert an~hn~ed ~n the tie~
~ y ela~tic deform~tion, th~ clip exerts a downwardly
di~ for~e on the rall and an upwardly directed for~e
on the in~er~.
Sin~e the ela6~ic defo~ma~ion o~ the ~lip iB ~
~ire¢t func~ion o~ th~ po~itlon~ng of th~ in~ert in the
tie, lt will be unde~stood that any ~ariation in such
pasltioning during manuf~cture o~ t~eB will l~ad to
~nc~ i rable variations in the force ~pplled to the rail .
In addition, the pre2~erlce of e~n insert anchor~d $n
2~) the tie compl ic~tes the de~ign of the tie and can weaken
it, par~icularly with respe~t to lateral forces ln small-
r~dlus cur~es.
Also, DE-A-38 26 362 de~c~i~es a dev~c~ for
fastening a t~a~k rail on a tie pr~vided with a
longi~ A 1 ca~ity i~ which ~ flex~ble Rupport p~d is
re~eived, the devlce being of the type includin~ side
clips con~ti~ted by Ypxi~g~ ea~h having ~t lea~t one
helic~l loop ~or bein~ put under ten~ion by elastic
d~form~tion ~nd fo~ lo~king at lea~t one length in
ret~i n~ ~ abutment ~ir~tly again~t ~he inte~nal sidewalls
of saia c~vlty ~nd ~ ]y in thrust on the b~se of the
rail.
Ilo.~ x, that device doe~ not ensure effective
retention o~ the rall and it ls relatively flifficult to
install.
An ob~-c~ of the present ~nvention is to solve thes-
te~..hn.i~l problem~ in s~isfactory manner.
1 a Corrected sheet
t Engl i sh pagination~
Ac~ordin~ to the ln~rent~ on~ t~is obJ--~t is ~c:hieved
by ~ean~ of a devlco for f a~tening a tra~k rail on a tie,
the device c:ompr~ 8ing ln partit::ular a ~lexible ~upport
pad and lateral cl lps congtituted by loops, and ~eing
S characte~ized in that ~ald tie includes a ~ongitudinal
cavi~y in whic:h the "~ L~J~ l, pad i~ recel~red, and in that
Qald side clips a~e constituted by ~spring~ e~c~h incl udlng
at least one helical loop desi~ne~ to b~ put under
tenQlon by ela~tlc deformation and b~r locking at least
10 one length in retelinln~ abutment syalnst the intern~l
~i -' h~ of ~aid ca~i~y and ~y applying thru~t again~t
the hase of the ra~l.
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The helical loop may optionally comprise a plurality
of turns. This design makes it possible to provide
spring clips that are very flexible and suitable for co-
operating with support pads having very low stiffness, of
the order of 20 kN/mm.
According to an advantageous characteristic, at
least one of the clip end lengths is bent to fit in
thrust contact against the edge of the base of the rail.
In a first variant embodiment, each of said spring
clips comprises a helical loop with two end lengths, one
of which thrusts against the base of the rail while the
other of which thrusts against the internal sidewall of
the cavity.
In a preferred variant embodiment, each spring clip
is symmetrical about an axis extending transversely to
the rail and comprises two helical loops connected
together by a link length designed to extend at least in
part in thrust contact both against the internal
sidewalls of said cavity and against the base of the
rail.
The link length may be rectilinear or curved and it
optionally connects with the helical loops via two bends
fitting against the edge of the base of the rail.
According to another characteristic, the top
portions of the internal sidewalls of said cavity are
provided with respective lips projecting towards the
inside of the opening so as to define respective bottom
thrust faces for locking the end lengths or the link
length of the springs.
Also, the profile of the bottom thrust face of the
lip fits round the profile of the end length or of the
link length to enable snap-fastening thereof.
In a variant, said cavity includes internal
sidewalls that are inclined so as to form a tapering
opening whose width is slightly greater than that of the
base of the rail.
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Optionally, the top portions of the internal
sidewalls of said cavity project above the level of the
top face of the tie.
Preferably, the internal face of said cavity is
secured to a lining constituted by a baseplate that is
preferably made of metal and/or of a layer of
electrically insulating material; said layer may lie
either on the external wall of the baseplate or on the
internal wall of the cavity or of the baseplate, or in
any other combination, applied on the external wall of
the baseplate, it guarantees good adhesion with concrete
and consequently satisfactory fastening with the tie.
For application on the internal wall of the cavity or of
the baseplate, the material should be chosen as a
function of its friction characteristics.
A first possibility consists in making said loop
springs from a plate of circular or quadrilateral
section.
Another possibility consists in making said loop
springs from a plate of rectangular section, using flat
strip steel.
According to yet another characteristic, the
resultant of the thrust forces of the springs on the base
of the rail is inclined to the vertical at an angle lying
in the range 20~ to 60~. By reaction, this force
resultant is taken up by the inclined internal face of
the cavity.
The invention also provides a method of mounting a
rail fastening device of the above type, characterized in
that the stiffness, the shape, and the dimensions of the
spring clips are initially chosen mainly as a function of
the thickness and of the flexibility of the support pad
so as to obtain thrust from the clips on the base of the
rail that is directed along a resultant which is inclined
relative to the vertical at an angle a lying in the range
20~ to 60~ by putting the loops under tension and locking
them in said cavity.
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The device of the invention is symmetrical about the
transverse mid-axis of the rail and therefore possesses
greater effectiveness.
Also, it is very easy to install the clips and there
is no need for an additional part such as an insert. The
thrust force on the rail obtained by elastic deformation
of the spring clip does not depend on the shape of the
cavity and is therefore independent of the accuracy with
which the cavity is positioned relative to the tie; this
guarantees excellent constancy for the thrust force.
The longitudinal cavity for receiving the rail and
locking the clips can be made when the tie is
manufactured. When the cavity is provided with a lining
including a metal baseplate, the special shape of the
cavity guarantees reliable anchoring of the load-bearing
surface in the tie.
The present invention will be better understood on
reading the following description accompanied by the
drawings, in which:
~ Figures la and lb are side views in fragmentary
longitudinal section on lines Ia and Ib respectively of
two embodiments of the device of the invention;
~ Figure 2 is a cross-section view of the device of
the invention on line II-II; the lefthand portion
corresponds to the embodiment of Figure la and the
righthand portion to the embodiment of Figure lb;
~ Figure 3 is a half-view in vertical section of a
second embodiment of the invention;
~ Figure 4 is a half-view in vertical section of a
third embodiment with the clip prior to installation;
~ Figure 5 is a half-view in vertical section of the
embodiment of Figure 4 with the clip in the installed
position;
~ Figures 6 and 7 are half-views in vertical section
of two other embodiments of the invention with the clips
in the installed position; and
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~ Figure 8 is a section view through yet another
embodiment of the invention.
The device of the invention shown in Figures la and
lb in side view is for fastening a rail R to a tie T,
generally made of concrete, by means of loop clips 1.
According to the invention, the tie T has a
longitudinal cavity 2 in which there is received a
flexible support pad 3 for the base of the rail R. The
cavity 2 extends over the entire width of the tie T. The
flexibility and the thickness of the pad 3 are determined
so that pad depression under passage of wheel loads
creates clearance allowing the rail to rotate, where
necessary, particularly in curves. Nevertheless, such
rotation is advantageously restricted by contact being
reestablished between the end length 12 or the link
length 11 and the internal wall of the cavity 2.
The side clips are constituted by preferably metal
springs 1 having at least one helical loop 10 made up of
one or more turns 100. The loops 10 are deformed
elastically to create the thrust force on the base of the
rail R. This thrust is achieved by putting the loops lO
under tension and it is maintained by locking the end
lengths 12 in retaining abutment against the internal
sidewalls 20 of the cavity 2. The tendency of the loop
to relax produces thrust from at least one of the lengths
against the edge B of the rail. The quality of contact
between the end lengths 11 and the internal sidewalls 20
of the cavity 2 is improved by securely covering the
walls, and in particular the internal sidewalls 20, with
a lining 21 constituted by a baseplate that is preferably
made of metal and/or of a layer of appropriate material
having good electrical insulation properties. This layer
may cover either the external wall of the baseplate or
the internal wall of the cavity 2 or of the metal
baseplate, or any other combination. Applied on the
external wall of the baseplate (see Figure 8) its good
adhesion properties guarantee satisfactory fastening to
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the concrete of the tie T, whereas applied to the
internal wall of the cavity or of the baseplate, it
participates in friction phenomena.
In the embodiment of Figures la, lb, and 2, the
spring clips 1 are symmetrical about an axis extending
transversely to the rail and each comprises two helical
loops 10 connected together by a link length 11 designed
to extend at least partially in thrust contact against
the internal sidewalls 20 of the wall of the cavity 2 or
of its lining 21. The link length 11 may be rectilinear
as shown in Figures lb and 2 (righthand portion) fitting
against the side edge B of the base of the rail R. In
this case, the link length 11 is connected to the two
helical loops 10 by two bends 110 which, in the absence
of any wheel loading, are in contact with the internal
sidewalls 20. The link length 11 thus forms a spacer for
positioning the rail by contact with the internal
sidewalls 20 and with the edge B of the rail R. Still in
this embodiment, the end lengths 12 are rectilinear and
extend in contact with the internal sidewalls 20 over
their entire lengths. In this position, the end lengths
are not in contact with the rail in its installed
position. It is also possible for the link length 11 to
be curved, as shown in Figures la and 2 (lefthand
portion). In this case, the link length 11 is spaced
apart from the edge B of the rail R but comes into
contact along its entire length with the internal
sidewalls 20 of the cavity 2; the end length 12 is bent
so as to fit against and apply thrust to the edge B of
the rail R.
The thrust force is exerted on the rail via the bent
portions of the end lengths 12 (Figure la) or via the
bends 110 of the link length 11 (Figure lb). This thrust
force on the rail is balanced by a reaction force from
the link length 11 or the end lengths 12 on the internal
sidewalls 20.
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The cavity 2 has internal sidewalls 20 that are
inclined so as to form a tapering opening of width
slightly greater than that of the base of the rail R,
thereby enabling the rail to be accurately positioned on
the pad 3.
In the embodiment of the invention shown in
Figure 3, the top portions of the internal sidewalls 20
of the cavity 2 are provided with respective lips 22.
These lips project into the opening so as to define
bottom thrust surfaces 22a for locking the end lengths
12a, 12b.
After elastic deformation of a loop 10, the end
lengths 12a, 12b snap into the cavity 2 between the edge
B of the rail R and the lip 22 and thus remain in
retaining abutment against the bottom thrust face 22a
whose profile fits against the profile of the end
lengths.
Figure 4 shows a spring clip 1 before being
installed in the cavity 2. The loop is made in this case
using a rod of square quadrilateral section.
The link length 11 rests on the top portion of the
internal sidewalls 20 of the cavity 2 while the end
lengths 12 rest against the edge B of the base of the
rail R.
The top portions of the internal sidewalls 20 have
respective inclined faces 23 extending to the lips 22 and
possibly projecting above the level of the top face of
the tie. Each inclined face 23 provides sliding contact
for the link length 11 of the spring 1 when thrust is
applied on the loop 10 towards the inside of the cavity 2
in direction F until the link length snaps under the lip
22 and locks in contact with the bottom thrust face 22a.
Simultaneously, the end lengths 12 slide over the
base of the rail R towards the inside of the cavity 2 and
lock in abutment against the internal sidewalls 20 and
the edge B of said base, as shown in Figure 5.
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The loop 10 is then under tension and creates the
thrust force on the rail via the bent portion of the end
lengths 12. The link length bears locally against an
inclined face 26 set back relative to the longitudinal
extent of the top portion of the lip 22.
Figure 6 shows another embodiment in which the top
portions of the internal sidewalls 20 have rounded edges
24 located above a hollow housing 25 for receiving the
link length 11 to lock it by snap-fastening after sliding
an elastic deformation in contact with the edge 24.
Figure 7 should be compared with Figure 4 and it
shows yet another embodiment in which the end length 12
is locked firstly by being subjected to elastic
deformation on contact with the inclined face 23 situated
at the top of the internal sidewalls 20, and then by
snap-fastening beneath the lip 22 in contact with the
bottom thrust face 22a.
The link length 11 is wsidewalld in the cavity 2
between the edge B of the base of the rail R and the
internal sidewalls 20, fitting against said edge B by
means of bends 110 (see Figure 2, righthand portion).
Figure 8 shows yet another embodiment of the
invention in which the helical loop 10 is asymmetrical
having a first end length 12a pressing against the base
of the rail R by fitting against its edge B, and a second
end length 12b pressing against the internal sidewall 20
of the cavity 2.
In this embodiment, it is preferable for the loop 10
to be made from flat steel strip and the layer of
electrically insulating material is applied to the
external wall of the lining 21 in contact with the
concrete of the tie T to improve fastening.
In all of the embodiments shown, the direction of
the resultant of the thrust forces from the loops 10 of
the springs l on the base of the rail R is inclined at an
angle a lying in the range 20~ to 60~ relative to the
vertical.
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The rail fastening device is assembled by initially
selecting the stiffness, the shape, and the dimensions of
the spring clips 1 having loops 10, mainly as a function
of the thickness and the flexibility of the support pad 3
so as to obtain a thrust force from the springs on the
base on the rail R that is directed along a resultant
inclined at an angle a relative to the vertical by
putting the loops 10 under tension and locking them in
the cavity 2.
