U.S. patent application number 16/349424 was filed with the patent office on 2019-09-19 for tension clamp, guide plate and fastening point for securing a rail to a ground surface.
The applicant listed for this patent is Vossloh-Werke GmbH. Invention is credited to Winfried Bosterling.
Application Number | 20190284765 16/349424 |
Document ID | / |
Family ID | 60302114 |
Filed Date | 2019-09-19 |
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United States Patent
Application |
20190284765 |
Kind Code |
A1 |
Bosterling; Winfried |
September 19, 2019 |
Tension Clamp, Guide Plate and Fastening Point for Securing a Rail
to a Ground Surface
Abstract
The invention relates to a tension clamp for holding down a rail
for rail vehicles. It includes a middle section with two legs, two
torsion sections connected to the legs leading laterally outwards
and having a support zone on their underside, by which the tension
clamp is supported during use, and two supporting arms connected to
the torsion sections. The supporting arms extend to the front side
of the tension clamp and have a spring section and a support
section, which has a support zone by which they are supported
during use. The support sections of the supporting arms point
laterally outwards so that the straight lines intersect in a region
located on the rear side of the tension clamp. The invention also
relates to a guide plate that protects a tension clamp against
breakage during excitation in the range of its natural frequency,
and a rail fastening point.
Inventors: |
Bosterling; Winfried;
(Neuenrade, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Vossloh-Werke GmbH |
Werdohl |
|
DE |
|
|
Family ID: |
60302114 |
Appl. No.: |
16/349424 |
Filed: |
November 9, 2017 |
PCT Filed: |
November 9, 2017 |
PCT NO: |
PCT/EP2017/078786 |
371 Date: |
May 13, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
E01B 2201/00 20130101;
E01B 9/303 20130101; E01B 9/483 20130101 |
International
Class: |
E01B 9/30 20060101
E01B009/30 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 16, 2016 |
DE |
10 2016 122 062.0 |
May 30, 2017 |
DE |
10 2017 111 781.4 |
Claims
1. A tension clamp for elastically holding down a rail for rail
vehicles, said rail comprising a foot, a web standing on the foot
and a rail head carried by the web, the tension clamp comprising: a
loop-shaped middle section, which has two legs and a base section
connecting the legs to each other, wherein a free end face of the
base section faces a front side, a free upper side of the
loop-shaped middle section faces the free upper side of the tension
clamp and the legs of the loop-shaped middle section, with their
ends being remote from the base section, face a rear side of the
tension clamp; two torsion sections, one of which is connected
respectively to an end of one of the legs of the loop-shaped middle
section, said end facing away from the base section, wherein the
torsion sections lead laterally outwards respectively starting from
their respectively associated leg, and have a support zone on an
underside, by means of which the tension clamp is supported on a
component carrying it during use; and two supporting arms, one of
which is connected respectively to an end of one of the torsion
sections, said end facing away from the associated leg of the
loop-shaped middle section, wherein the supporting arms extend in
the direction of a front side of the tension clamp and each have a
spring section curved towards the free upper side of the tension
clamp and also have an adjoining support section ending at a free
end of the supporting arm, said support section comprising a
support zone on its underside, by means of which the respective
supporting arm is supported during use on the foot of the rail to
be fastened, wherein the support sections of the supporting arms
each point laterally outwards with respect to the loop-shaped
middle section of the tension clamp in such a way that, when seen
in plan view from above with respect to the tension clamp, straight
lines, which respectively connect a center of the support zones of
the supporting arms with a center of the support zone associated
with their respective supporting arm, intersect in a region located
on the rear side of the tension clamp.
2. The tension clamp according to claim 1, wherein between the
straight lines an angle is enclosed, which is at least 60.degree.
when seen in plan view with respect to the tension clamp.
3. The tension clamp according to claim 1, wherein the angle
enclosed between the straight lines is at most 120.degree., when
seen in plan view with respect to the tension clamp.
4. The tension clamp according to claim 1, wherein the supporting
arms, when seen in plan view with respect to the tension clamp, run
respectively outwardly away from the loop-shaped middle section,
starting from their associated torsion section.
5. The tension clamp according to claim 1, wherein in the
supporting arms, the spring section merges respectively into the
associated support section in a continuous curve.
6. The tension clamp according to claim 1, wherein the support
zones of the supporting arms, when seen in plan view with respect
to the tension clamp, extend in a direction of the front side V of
the tension clamp relative to the free end face of the base section
of the loop-shaped middle section.
7. The tension clamp according to claim 1, wherein for the distance
AS, measured parallel to an axis of symmetry of the tension clamp,
between the center of the support zones of the supporting arms and
the intersection of the straight lines, which respectively connect
the center of the support zones of the supporting arms with the
center of the support zone of the torsion section associated with
the respective supporting arm, and for the distance AG, also
measured parallel to the axis of symmetry of the tension clamp,
between the support zones of the supporting arms and the centers of
the support zones of the torsion sections, the following applies:
1.2.times.AG.ltoreq.AS.ltoreq..ltoreq.1.8AG.
8. The tension clamp according to claim 7, wherein for the distance
AG and the distance AS, the following applies:
1.3.times.AG.ltoreq.AS.ltoreq.1.7AG.
9. A guide plate for laterally guiding a rail for rail vehicles in
a rail fastening point, the rail comprising a foot, a web standing
on the foot and a rail head carried by the web, wherein a support
surface is provided on a free upper side of a tension clamp which
is positioned on the guide plate, said tension clamp serving to
elastically hold down the rail in the fastening point, wherein the
tension clamp applies an elastic hold-down force over two
supporting arms, which are supported during use with the two
supporting arms' free support sections on the foot of the rail
fastened in the fastening point, wherein at least two stops are
provided on the support surface, which limit at least the movements
of the supporting arms of the tension clamp perpendicular to a
contact surface, when the tension clamp is positioned on the guide
plate.
10. The guide plate according to claim 9, wherein the stops are
designed in the manner of supports, which respectively carry at
their free end face a fillet-like seat for the associated
supporting arm of the tension clamp.
11. The guide plate according to claim 9, wherein the stops have
respectively an elastic material on their free end face assigned to
the respective supporting arm of the tension clamp, said material
dampening a contact with the associated supporting arm.
12. The guide plate according to claim 9, wherein on the support
surface depressions are formed, in which the tension clamp is
respectively supported during use with a section, and in that the
depressions are covered with a damping or elastic material in the
region of their contact surfaces, which come into contact with the
tension clamp.
13. The guide plate according to claim 12, wherein the depressions
are adapted to the shape of the respectively associated sections,
of the tension clamp such that during use the section of the
tension clamp seated in the respective depression engages
positively on the contact surface of the depression at least over a
part of its length.
14. The guide plate according to claim 12, wherein the sections of
the tension clamp assigned to the depressions are torsion sections,
which are bent in a continuous curve towards an underside of the
tension clamp, and in that the depressions are correspondingly
arc-shaped in the course of the torsion sections, so that the
torsion sections engage positively and tightly over a partial
length of their tension curve when the tension clamp is positioned
on the guide plate, and are seated in the associated
depression.
15. A fastening point in which a rail for a rail vehicle is
fastened on a ground surface, the rail comprising a foot, a web
standing on the foot and a rail head carried by the web, wherein
the fastening point comprises a guide plate acting against a
lateral edge of the foot of the rail for laterally guiding the rail
and a tension clamp positioned on the guide plate, said tension
clamp being supported by means of free support sections and
supporting arms on the foot of the rail, in order to apply an
elastic hold-down force on the rail, wherein the guide plate is
designed according to claim 9.
16. The fastening point according to claim 15, wherein the
fastening point comprises a tension element, such as a sleeper
screw or a sleeper bolt, by means of which the tension clamp is
braced against the ground.
17. The fastening point according to claim 15, wherein an
insulating element is arranged between the support sections of the
supporting arms of the tension clamp and a rail foot, in that this
insulating element insulates the tension clamp electrically with
respect to the rail foot and, at least in sections, comprises a
damping or an elastically yielding material.
Description
[0001] The invention relates to a tension clamp and a guide plate
for fastening a rail for rail vehicles.
[0002] Moreover, the invention relates to a fastening point in
which a rail for a rail vehicle is fastened on a ground.
[0003] The ground on which a fastening point according to the
invention is established is typically a sleeper or plate made of a
solid material such as concrete or similar. However, the fastening
point according to the invention can also be mounted on
conventional wooden sleepers serving as the ground surface.
[0004] The rails fastened by means of the components and fastening
points which are improved by the invention usually have a rail
foot, a rail web standing on the rail foot and a rail head carried
by the rail web.
[0005] Fastening points of the type in question here or the system
comprising components in question here for the manufacture of such
fastening points, are known in many variants. Examples of such
systems are presented in the Applicant's published brochures,
available for download for example via the URL
http://www.vossloh-fastening-systems.com/de/produkte_2015/anwendungsberei-
che/conventional_rail/conventional_rail_thtml. The brochure "System
W 41 U--Highly elastic rail fastening for conventional rail and
high speed the universal solution for ballasted track with
grooveless concrete sleepers", as of September 2014, or the
brochure "System W 21--Highly elastic rail fastening for high speed
and conventional rail the modern solution for ballasted track with
concrete sleepers", as of February 2015.
[0006] The known rail fastening systems (see, for example, WO
2006/005543 A1 and the other patent publications cited below) and
rail fastening points produced therefrom accordingly respectively
typically comprise' as components from which they are assembled, a
guide plate (see, for example, WO 2010/091725 A1), which is
provided for laterally guiding the rail, a W-shaped tension clamp
provided for placement on the guide plate (see, for example, WO
2012/059374 A1) and a tension element (see, for example, WO
2014/029705 A1), which is provided for clamping the tension clamp
against the ground surface (see for example WO 2006/005543 A1).
[0007] Along with these basic components of rail fastening systems,
supplementary elements may also be respectively used, such as
optional shims (see, for example, WO 2011/110456 A1), which are
used to adjust the height of the rail above the ground or to
distribute the loads occurring when passing over the rail by a rail
vehicle, elastic intermediate layers (see WO 2005/010277 A1, for
example), which are likewise laid under the rail or the other
plate-shaped components of the system in order to ensure a certain
flexibility in the direction of gravity for the rail in the
fastening point formed respectively from the system, and insulator
elements (see, for example, WO 2015/051 841 A1), which are
typically located between the suspension element and the foot of
the rail to be fastened to ensure optimised electrical insulation
against the ground surface.
[0008] The W- or .omega.-shaped tension clamps are usually
one-piece and bent in one go from a spring steel wire. In this
case, they have a usually V- or U-shaped middle section which has
two legs aligned parallel to each other. These legs define between
them a free space through which the respective tension means,
typically a sleeper screw or a bolt, is guided into the ground
surface by means of its shaft. At one end, the legs are usually
connected to each other via a base section which faces the rail
associated with the front side of the tension clamp. At the other
end of the legs of the middle section, however, a torsion section
is typically respectively formed, which emanates from the
respectively associated leg of the middle section, directed
laterally outward.
[0009] In this case, the torsion sections are bent in the direction
of the underside of the tension clamp so that the suspension
element can be supported during use on a support surface in the
region of the torsion sections in a support zone formed on the
respective torsion section, which is designed on the upper side of
the component carrying the suspension element, for example a guide
plate. At their end facing away from the middle section, the
torsion sections usually merge respectively into a supporting arm,
which, when seen in a lateral view, is typically curved in an
arc-like manner in the direction of the upper side of the tension
clamp and, when seen in plan view, is aligned in the direction of
the front side of the rail to be fastened. The free end sections of
the supporting arms typically point in the direction of the middle
section. With these end sections, the tension clamp is supported
during use on the foot of the rail to be fastened.
[0010] On the underside of the end sections support zones are
formed, with which the end sections are supported on the rail foot
during use. In the case of the tension clamps known in practice,
the support zones of the supporting arms and the torsion sections
are located regularly on a straight line which is aligned
substantially parallel to the axis of symmetry of the tension
clamp.
[0011] The elastic flexibility and thereby the hold-down force
exerted on the rail via the supporting arm can be adapted to the
requirements and stresses that result in practical use, via the
shape of the supporting arm as well as the form and alignment of
its end sections. In the same way, the spring behaviour of the
tension clamp can be influenced by the shaping of the torsion
sections and of the middle section as well as the transition
sections which may be present between the middle section and the
torsion sections as well as between the torsion sections and the
supporting arms.
[0012] The guide plates usually have on their upper side form
elements on which the suspension element to be arranged on the
respective guide plate is guided in such a way that, during use, it
retains its position even under the loads occurring in practice.
For this purpose for example fillet-like depressions, in which the
torsion sections of the suspension element are seated during use,
or a central web can be formed on the upper side of the guide
plate, on which the middle loop is guided and supported.
[0013] It has been found that the lifespan of tension clamps
depends crucially on their vibration behaviour. It is known that
tension clamps usually have several natural frequencies.
[0014] In practical use, the tension clamps are excited to vibrate
when a train passes over the rail held down by the tension clamps.
Periodically recurring faults on the rail or on the wheels of rail
vehicles can lead to resonance peaks. If these are close to one of
the natural frequencies of the tension clamp, there is a dramatic
increase in the vibration amplitude, in particular in the region of
the supporting arms of the tension clamp. The result is a
premature, sudden failure of the tension clamp due to breakage,
which typically occurs in the region of its torsion sections or in
the transition region of the supporting arms to the torsion
sections.
[0015] In an article published in the journal El-Der
Eisenbahningenieur, August 2016, page 25 ff., by Maximilian
Steiger, studies on the optimisation of the dynamic behaviour of
rail fasteners are reported. As a result of these studies, three
measures for avoiding damage to rail fastenings due to resonances
have been proposed.
[0016] The first of the proposed measures comprises the arrangement
of vibration-damping additional elements on the tension clamp.
These, for example, disc or tube-like additional elements are to be
arranged in particular in the region of the supporting arms.
However, the research has also shown that such vibration absorbers,
while highly effective, are also destructive, so that the article
comes to the conclusion that the practical usability of such
absorbers is questionable.
[0017] As a second measure, the article has proposed an enlargement
of the support surface provided for the tension clamp on the
respective guide plate. Thus, the investigation has shown that
increased resonances can increase the natural frequencies of the
tension clamps to such an extent that they are outside the range in
which they are typically excited in practice. However, in practice
the relative movements, which are performed by the tension clamp
and the guide plate when passing over the rail laterally guided by
the guide plate and held down by the tension clamp, as a result of
inevitable horizontal and vertical movements of the rail proved to
be problematic. These movements led to increased wear in the region
of the widened supports, which calls into question the feasibility
of the proposed support widening as a whole.
[0018] As a third measure, a change in the geometry of the tension
clamp itself was finally proposed in the article. This measure also
aims to increase the natural frequency of the tension clamp to a
range outside of the excitement occurring in practice. The shape of
the supporting arms and the distance of the supporting arms to the
so-called "tilt axis" of the supporting arms has been recognised as
a critical design feature. The straight lines have been designated
as tilt axes of the supporting arms in this context, said lines
connecting the centre of the zone with which the respective
supporting arm is supported on the rail foot at its free end during
use, and the centre of the zone in which the respective supporting
arm is supported with its other end on the guide plate. This zone
is typically in the region of the torsion section assigned to the
respective supporting arm. By reducing the distance to the tilt
axis of the described arc of the supporting arms, e.g. a lowering
of the height of the arc over the guide plate, in turn the natural
frequencies could be increased sufficiently.
[0019] However, the reduction of the geometry and in particular the
arc height of the supporting arms is accompanied by a fundamental
change in the resilient properties. This can go so far that the
tension clamp is no longer optimally usable for the respective
purpose or no longer optimally fulfils the requirements placed on
it with respect to its elastic behaviour.
[0020] Against this background, the object has arisen to identify
practical measures for the design of one or a plurality of
interacting components for a rail fastening point with the aim of
maximising the life of the system formed from the components or of
its individual components.
[0021] To achieve this object, the invention proposes the
particular designs of a tension clamp or guide plate which are
generally disclosed in Claims 1 and 7, wherein each of these design
measures alone, i.e. isolated from the other measures, provides a
solution to the above object and thus leads to an improvement in
the vibration behaviour of the overall system and in particular the
tension clamp installed in this system. It goes without saying that
the measures proposed here by the invention can be combined in any
way with each other in order to develop an optimised effect.
[0022] Advantageous embodiments of the invention are defined in the
dependent claims and, like the general concept of the invention,
are explained in detail in the following.
[0023] A fastening point according to the invention is accordingly
characterised in that a tension clamp designed according to the
invention or a guide plate designed according to the invention are
installed therein. Again, it goes without saying that the tension
clamp according to the invention and the guide plate according to
the invention respectively individually lead to a significant
improvement in the vibration behaviour, so can be used as
alternatives to each other, but produce an optimal result when
combined together.
[0024] A measure for improving the vibration behaviour of the
tension clamp itself, which is essential for the invention and
particularly effective in view of the issue addressed here, is
thus, in each of the supporting arms of the tension clamp, to shift
the zone with which the respective arm is supported on the rail
foot during use, such that the natural frequency is moved to a
region in which it no longer causes vibrational excitation in
practical use.
[0025] For this purpose, the invention proposes a tension clamp for
elastically holding down a rail for rail vehicles, which comprises
a foot, a web standing on the foot and a rail head carried by the
web, which in a conventional manner comprises [0026] a loop-shaped
middle section having two legs and a base section connecting the
legs to each other, wherein the free end face of the base section
faces the front side, the free upper side of the middle section
faces the upper side of the tension clamp and the legs of the
middle section, with their ends being remote from the base section,
face towards the rear side of the tension clamp, [0027] two torsion
sections, one of which is connected respectively to the end of one
of the legs of the middle section, said end facing away from the
base section, wherein the torsion sections lead laterally outwards
respectively starting from their respectively associated leg, and
have a support zone on their underside, by means of which the
tension clamp is supported on the component carrying it during use,
and [0028] two supporting arms, one of which is connected
respectively to the end of one of the torsion sections, said end
facing away from the associated leg of the middle section, wherein
the supporting arms extend in the direction of the front side of
the tension clamp and each have a spring section curved towards the
upper side of the tension clamp and also have an adjoining support
section ending at the free end of the supporting arm, said support
section comprising a support zone on its underside, by means of
which the respective supporting arm is supported during use on the
foot of the rail to be fastened.
[0029] According to the invention, the support sections of the
supporting arms point respectively laterally outward with respect
to the middle section of the tension clamp, such that when viewed
in plan view from above with respect to the tension clamp, the
straight lines, which respectively connect the centre of the
support zones of the supporting arms with the centre of the support
zone of the torsion section associated with the respective
supporting arm, intersect in a region located on the rear side of
the tension clamp.
[0030] Surprisingly, it has been shown that, in a tension clamp
according to the invention, the natural frequencies of the tension
clamp can be effectively increased so far that they lie outside of
the excitation frequencies that occur during practical use, in that
the support zones of the support sections of the supporting arms
and the torsion sections, to which the respective supporting arm is
connected, are no longer located on a line parallel to the axis of
symmetry of the tension clamp, but on a straight line, which
encloses an acute angle running in the direction of the rear side
of the tension clamp. Due to said invention, the durability of the
tension clamp is significantly improved, without this leading to a
significant change in the resilience behaviour. The invention thus
eliminates the problems encountered in the existing practice,
without a fundamental redesign of the components of a rail
fastening system being required.
[0031] Of course, the invention does not exclude that the measures
proposed in the prior art with regard to optimised dynamic
behaviour of the tension clamp (see, for example, the
above-mentioned article by Maximilian Steiger) are also implemented
in a tension clamp according to the invention, based on the design
according to the invention to achieve a further optimised vibration
behaviour. These include, in particular, the reduction in the
amount of bending of the supporting arms over the support surface
on which the tension clamp is mounted, and the increase in the
support zones, with which the support sections of the supporting
arms are seated on the rail foot during use.
[0032] When seen in plan view with respect to the tension clamp,
the straight lines running through the centres of the support zones
of the respectively associated support sections and torsion
sections preferably enclose an angle of at least 60.degree., in
particular more than 60.degree., or at least 90.degree., in
particular more than 90.degree., in order to establish the greatest
possible distance between the natural frequencies of the tension
clamp and a possible excitation frequency. With regard to the
resilient action of the tension clamp, it has proved to be
advantageous if the angle between the straight lines, seen in plan
view with respect to the tension clamp, is a maximum of
120.degree., in particular less than 120.degree..
[0033] For shifting the natural frequencies of a tension clamp
according to the invention, an additional optional design element
may be used, in that the supporting arms, seen in plan view with
respect to the tension clamp, extend respectively outwardly away
from the middle section, starting from their associated torsion
section.
[0034] It also proves to be advantageous in view of the
manufacturability and durability of a tension clamp according to
the invention, if, also optionally, the spring section of the
supporting arms respectively merges into the associated support
section in a continuous curve.
[0035] The following feature may further contribute to the
durability and optimal resilience behaviour of a tension clamp
according to the invention, if, also optionally, when viewed in
plan view with respect to the tension clamp, the support zones of
the supporting arms project in the direction of the front side of
the tension clamp, with respect to the free end face of the base
section of the middle section.
[0036] A vibration behaviour of the tension clamps formed according
to the invention, which is particularly well adapted to the
conditions in practice, may occur if the following applies for the
distance AS, measured parallel to the axis of symmetry of the
tension clamp, between the centre of the support zones of the
supporting arms and the intersection of the straight lines, which
respectively connect the centre of the support zones of the
supporting arms with the centre of the support zone of the torsion
section associated with the respective supporting arm, and for the
distance AG, likewise measured parallel to the axis of symmetry,
between the support zones of the supporting arms and the centre of
the support zones of the torsion sections:
1.2.times.AG.ltoreq.AS.ltoreq.1.8AG.
[0037] It has proven to be particularly practical if:
1.3.times.AG.ltoreq.AS.ltoreq.1.7AG.
[0038] A guide plate according to the invention is provided with
form elements, i.e. structural design features, which protect the
supporting arms of the tension clamp arranged on the guide plate
against excessive vibration amplitudes during use, which occur in
the case of a vibration excitation in the range of one of the
natural frequencies of the tension clamp.
[0039] For this purpose, in a guide plate according to the
invention for laterally guiding a rail for rail vehicles in a rail
fastening point, the rail comprising a foot, a web standing on the
foot and a rail head carried by the web, a support surface is
provided on the free upper side for a tension clamp to be
positioned on the guide plate, said tension clamp serving to
provide elastic holddown in the fastening point, wherein this clamp
applies the elastic hold-down force via two supporting arms, which
are supported during use with their free end sections on the foot
of the rail fastened in the fastening point. According to the
invention, in such a guide plate at least two stops are provided on
the support surface, which limit at least the movements of the
supporting arms of the tension clamp perpendicular to the contact
surface, when the tension clamp is positioned on the guide
plate.
[0040] Should the tension clamp reach natural frequency during use,
its supporting arms hit against the stops provided on the guide
plate according to the invention. These thus prevent the supporting
arms from performing too large vibrations that could otherwise lead
to breakage, even in a conventional tension clamp whose natural
frequencies are not sufficiently far from the excitation
frequency.
[0041] In order to catch the respective supporting arms safely when
they come into contact with the stops, the stops can be designed in
the manner of supports which carry on their respective free end
face a fillet-like seat for the associated supporting arm of the
tension clamp.
[0042] In order to dampen the shocks associated with the striking
of the supporting arms on the stops, the stops have an elastic
material on their free end face associated with the respective
supporting arm of the tension clamp, said material serving to
dampen a contact with the associated supporting arm.
[0043] For a guide plate designed according to the invention, it is
of course also understood that it may be expedient to implement
measures to optimise the dynamic behaviour, in addition to the
inventive design proposed in the prior art (see, for example, the
above-mentioned article by Maximilian Steiger).
[0044] Thus, in order to shift the natural frequencies of a tension
clamp mounted on the guide plate according to the invention, it may
be beneficial to form depressions on the support surface in a guide
plate according to the invention, the tension clamp being supported
in these depressions during use by means of a respective section,
and to cover these depressions with a damping or elastic material
in the region of their contact surfaces which come into contact
with the tension clamp. This material may be formed as a separately
manufactured insert or as a layer formed integrally bonded onto the
material of the guide plate.
[0045] Likewise, it may be expedient to adapt the depressions to
the shape of their respectively associated sections of the tension
clamp, in such a way that during use the section of the tension
clamp seated in the respective depression tightly engages
positively on the contact surface of the depression, at least over
part of its length, so the contact length between guide plate and
tension clamp is increased. An optimised effect of this measure is
obtained when the sections of the tension clamp assigned to the
depressions are torsion sections, which are bent in a continuous
curve towards the underside of the tension clamp, and the
depressions are formed in an arc-like manner, corresponding to the
curve of the torsion sections, so that in a tension clamp
positioned on the guide plate the torsion sections are seated in
the associated depressions engaging tightly and positively over a
partial length of their curve path. In the same way, it can have a
positive effect on the durability of a tension clamp arranged on
the guide plate, if the sections have a damping or elastically
yielding material in the region of the depressions provided there
for the support of the tension clamp. This material may also be
formed as a separately manufactured insert or as a layer formed
integrally bonded onto the material of the guide plate.
[0046] The guide plate is, as usual in the prior art, preferably
made in one piece out of a plastic, in particular a
fibre-reinforced plastic.
[0047] As explained above, a fastening point according to the
invention, in which a rail for a rail vehicle comprises a foot, a
web standing on the foot, and a rail head carried by the web, said
rail being fastened to a ground surface, has a guide plate acting
against the lateral edge of the foot of the rail for laterally
guiding the rail and a tension clamp positioned on the guide plate,
which is supported with the free end sections of its supporting
arms on the foot of the rail, in order to exert an elastic
hold-down force on the rail. The tension clamp or the guide plate
are formed in accordance with the invention, wherein in this case
it is also self evident that is possible for either only the
tension clamp or only the guide plate to be formed in accordance
with the invention, but when both the guide plate and the tension
clamp correspond to the provisos according to the invention optimal
results are achieved.
[0048] For clamping the tension clamp, a fastening point according
to the invention can comprise a tension element in a conventional
manner, such as a sleeper screw or a sleeper bolt, by means of
which the tension clamp is braced against the ground surface. The
tension element in question is typically guided through the space
delimited between the legs of the middle section of the tension
clamp, and through an underlying opening of the guide plate down to
the ground surface, where it is anchored. The anchoring can be
effected in a likewise conventional manner by means of a dowel
recessed into the ground surface or another suitable fastening.
[0049] In order to protect the tension clamp installed in a
fastening point for a rail of the type in question here, an
insulating element may be arranged between the end sections of the
supporting arms of the tension clamp and the rail foot, which
electrically insulates the tension clamp against the rail and
comprises dampening or elastically yielding material at least in
sections. Thus, the insulator may be formed, for example, as a
sandwich element, in which electrically insulating layers are
combined with damping or elastic layers, in order to achieve on one
hand the required electrical insulation and on the other hand a
vibrational separation of the rail from the tension clamp, with
sufficient resistance against the hold-down forces applied by the
tension clamp. The measures referred to here relating to the
insulating elements already contribute in their own right, i.e.
independently of the above-described inventive design features, to
improving the durability of the tension clamp used in a rail
fastening point according to the invention, but of course are
particularly advantageous in a design according to the invention of
a fastening point.
[0050] Another component that is used regularly in fastening points
of the type in question here is an elastic intermediate layer which
is usually arranged between the rail foot and the ground surface to
give the support of the rail a certain flexibility in the direction
of gravity. By adapting the damping behaviour of the elastic
intermediate layer to the excitation frequencies occurring in
practice, it is also possible to contribute to avoiding excessive
excitation of the tension clamp in the range of its natural
frequencies.
[0051] The invention is explained in more detail in the following
with reference to a drawing representing, in diagrammatic form, an
exemplary embodiment, The schematic drawings show the
following:
[0052] FIG. 1 shows a tension clamp according to the invention in
plan view from above.
[0053] FIG. 2 shows the tension clamp according to FIG. 1 in a
perspective view from its front side;
[0054] FIG. 3 shows the tension clamp according to FIGS. 1 and 2 in
a side view;
[0055] FIG. 4 shows a guide plate with a conventional tension clamp
arranged thereon in a perspective view from behind;
[0056] FIG. 5 shows the guide plate from FIG. 4 in a perspective
view from the front.
[0057] The tension clamp 1 according to the invention, shown in
FIGS. 1-3, bent in one piece from a spring wire with a circular
cross section, has a U-shaped middle section 2 with a curved base
section 3 associated with the front side V of the tension clamp and
legs 4, 5, having a straight form, connected thereon. On the upper
side of the legs 4, 5 of the middle section 2 associated with the
upper side O of the tension clamp 1, flattened contact surfaces 6,
7 are provided, on which during use a sleeper screw (not shown
here) is seated by means of its screw head, serving as a tension
element for tensioning the tension clamp 1.
[0058] At their ends facing away from the base section 3, and
pointing to the rear side R of the tension clamp 1, the legs 4, 5
of the middle section 2 merge respectively into a torsion section
8, 9 of the tension clamp 1. The torsion sections 8, 9 are
respectively bent in the direction of the underside U of the
tension clamp 1 and lead laterally outward away from the
respectively associated leg 4, 5. On their underside, the torsion
sections 8, 9 respectively have a support zone 10, 11, by means of
which they are seated during use on a support surface of a guide
plate.
[0059] At the end of the torsion sections 8, 9, respectively facing
away from the middle section 2, a supporting arm 12, 13 is
respectively connected. In the region of their spring sections 14,
15, the supporting arms 12, 13 are designed to be curved in an
arc-like manner respectively in the direction of the upper side O
of the tension clamp 1, and extend starting from the respective
torsion section 8, 9 in the direction of the front side V of the
tension clamp 1. Thus, they are aligned such that, seen in plan
view from above (FIG. 1), the distance of the supporting arms 12,
13, measured parallel to the connecting lines G between the centres
Z10, Z11 of the support zones 10, 11, increases starting
respectively from the torsion sections 8, 9.
[0060] At their free ends 16, 17, the supporting arms 12, 13
respectively end in a support section 18, 19, connecting on their
respective spring section 14, 15, by means of which the supporting
arm 12, 13 in the operative condition is seated on the rail (not
shown here) to be fastened in the respective rail fastening point.
On the underside of the support sections 18, 19 associated with the
underside U of the tension clamp 1, punctiform support zones 20, 21
are respectively formed thereto on the ends 16, 17 of the
supporting arms 12, 13.
[0061] The support sections 18, 19 are formed pointing outwards
from the middle section 2 in a continuous curve starting from the
respective spring section 14, 15, so that they conform tangentially
to a straight line aligned parallel to the connecting line G. The
length of the supporting arms 12, 13 is dimensioned so that the
punctiform support zones 20, 21, when seen in plan view from above
(FIG. 1), are located in front of the base section 3 of the middle
section 2 in the direction of the front side V of the tension clamp
1.
[0062] Due to the outward-pointing arrangement of the support
sections 18, 19 and the punctiform support zones 20, 21 of the
supporting arms 12, 13 located correspondingly laterally outwards,
the connecting lines G1, G2, which on the one hand (connecting line
G1) connect the centre Z10 of the support zone 10 of the torsion
section 8 with the punctiform support zone 20 of the supporting arm
12 connected to the torsion section 8, said support zone thus
itself representing the centre, and which on the on the other hand
(connecting line G2) connect the centre Z11 of the support zone 11
of the torsion section 9 with the punctiform support zone 21 of the
supporting arm 13 connected to the torsion section 9, said support
zone thus likewise itself representing the centre, are arranged at
an acute angle .beta.1 with respect to the axis of symmetry S of
the tension clamp 1 and comprise an angle .beta.2 of approx.
70.degree. therebetween. Accordingly, when seen in plan view from
above (FIG. 1), they intersect in a point of intersection SG
located behind the rear side R of the tension clamp 1.
[0063] The distance AS, measured parallel to the axis of symmetry
S, between the punctiform support zones 20, 21 of the supporting
arms 12, 13, said support zones themselves forming the centre, on
the one hand and the intersection SG on the other hand corresponds
to approx. 1.5 times the distance AG, also measured parallel to the
axis of symmetry S, of the punctiform support zones 20, 21 from the
centres Z10, Z11 of the support zones 10, 11 of the torsion
sections 8, 9. In practice, the distance AG can, for example, be
approx. 100 mm and the distance AS approx. 150 mm, wherein the
distance AS can be varied in the range of, for example, 130 mm to
170 mm, if this is expedient in terms of setting the natural
frequencies or due to structural conditions.
[0064] Practical tests have shown that the tension clamp 1 has
natural frequencies of at least 50% higher compared with a
conventionally shaped tension clamp 101 shown in FIGS. 4 and 5.
These are so high that even under unfavourable conditions of use,
as may be the case for example in tunnels or on bridges, there is
no excitation of the tension clamp 1 in the range of its natural
frequencies.
[0065] The tension clamp 101 shown in FIGS. 4 and 5, arranged on a
guide plate 100, has a U-shaped middle section 102 with legs
extending parallel to each other, which merge respectively into a
torsion section 108, 109 leading laterally outwards from the middle
section 102 and bent towards the underside U of the tension clamp
101. The torsion sections 108, 109 also respectively have a support
zone on their underside, with which they are seated on the guide
plate 100 during use.
[0066] Thus a supporting arm 112, 113 is also respectively
connected to its spring section 114, 115, curved upwards in an
arc-like manner, on the torsion sections 108, 109. In contrast to
the tension clamp 1 according to the invention, however, in the
case of the tension clamp 101, the support sections 118, 119 of the
tension clamp 101 ending at the free ends 116, 117 of the
supporting arms 112, 113 are bent in the direction of the middle
section 102, so that the ends 116, 117 of the tension clamp 101
directed towards one another and the connecting lines G1', G2',
which respectively interconnect the punctiform support zones of the
supporting arms 112, 113 to the centre Z110, Z111 of the support
zones on the respective associated torsion section 108, 109, are
aligned parallel to the axis of symmetry S' of the tension clamp
101.
[0067] In the case of the conventionally shaped tension clamp 101,
in order to prevent damage as a result of excessive vibration
movements as a result of excitation in the natural frequency range,
stops 126, 127 are provided on the support surface 125, which is
configured on the upper side of the guide plate 101 formed
integrally of a plastic approved for this purpose, said stops being
formed in the manner of supports. The stops 126, 127 are arranged
in the region of the greatest height of the respective spring
section 114, 115 of the tension clamp 101 and carry at their free
frontal end respectively a U-shaped receptacle 128, 129, whose
dimensions are proportioned so that the respective spring section
114, 115 is seated positively in the respective receptacle 128,
129, in the event that it comes into contact with the associated
stop 126, 127. In order to dampen the contact, the receptacle is
designed with a shock-absorbing material. The height position of
the receptacles 128, 129 is selected to be such that the spring
sections 114, 115 can perform the elastic movements required during
normal operation, but are supported in the receptacles 128, 129 in
the event of an excessive excitation exceeding those movements
which are to be expected during normal operation.
[0068] With the support zones Z110, Z111 provided in the region of
their torsion sections 108, 109, the tension clamp 101 is seated
respectively in a depression 130, 131 formed in the support surface
125 of the guide plate 100. The depressions 130, 131 are designed
in elevations 132, 133 formed on the contact surface 125. Their
size, thickness and height is designed so that the arc length BL,
which comprises a contact between the respective torsion section
108, 109 and the guide plate 100, is substantially greater than the
approximately punctiform contact, which would be between the
torsion sections 108, 109, if this were to be supported on a level
support surface. The purpose of the depressions 130, 131 being
configured in the elevations 132, 133 is that the position of the
torsion sections 108, 109 is the same with respect to the support
surface 125 as in the case of a support on a flat support surface
125, despite their being seated in the depressions 130, 131. The
depressions 130, 131 are also designed with a suitable damping
material to dampen the vibrations of the tension clamp 101.
REFERENCE NUMERALS
[0069] 1 Tension clamp [0070] 2 Middle section of the tension clamp
1 [0071] 3 Base section of the middle section 2 [0072] 4, 5 Legs of
the middle section 2 [0073] 6, 7 Contact surfaces of the legs 4, 5
[0074] 8, 9 Torsion sections of the tension clamp 1 [0075] 10, 11
Support zones of the torsion sections 8, 9 [0076] 12, 13 Supporting
arms of the tension clamp 1 [0077] 14, 15 Spring sections of the
supporting arms 12, 13 [0078] 16, 17 Free ends of the supporting
arms 12, 13 [0079] 18, 19 Support sections of the supporting arms
12, 13 [0080] 20,21 Punctiform support zones (=centre of the
support zones 20, 21) [0081] G, G1, G2 Connecting lines [0082] Z10,
Z11 Centres of the support zones 10, 11 [0083] .beta.1, .beta.2
Angles [0084] S Axis of symmetry of the tension clamp 1 [0085] 100
Guide plate [0086] 101 Tension clamp [0087] 102 U-shaped middle
section of the tension clamp 101 [0088] 108, 109 Torsion sections
the tension clamp 101 [0089] 112, 113 Supporting arm of the tension
clamp 101 [0090] 114, 115 Spring sections of the supporting arms
112, 113 [0091] 116, 117 Free ends of the supporting arms 112, 113
[0092] 118, 119 Support sections of the tension clamp 101 [0093]
125 Support surface of the guide plate 100 [0094] 126, 127 Stops
[0095] 128, 129 U-shaped receptacles (=seat) [0096] 130, 131
Depressions [0097] 132, 133 Elevations [0098] BL Arc length over
which there is contact between the respective torsion section 108,
109 and the guide plate 100 [0099] G1', G2' Connecting lines [0100]
Z110, Z111 Centre of the support zones of the torsion sections 108,
109 [0101] S' Axis of symmetry of the tension clamp 101 [0102] AG,
AS Distances [0103] O Upper side of the tension clamps 1, 101
[0104] U Underside of the tension clamp 1, 101 [0105] R Rear side
of the tension clamp 1, 101 [0106] SG point of intersection [0107]
V Front side of the tension clamp 1, 101
* * * * *
References