EP3541993B1 - Anchor clamp for fastening a rail to a subsurface - Google Patents

Description

The invention relates to a tension clamp for fastening a rail for rail vehicles according to the preamble of claim 1. Such a tension clamp is from the WO 2012/059374 A1 known.

According to the invention, such a tension clamp is suitable for a fastening point in which a rail for a rail vehicle is fastened to a ground.

The subsurface on which a fastening point according to the invention is erected is typically a threshold or a plate made of a solid material such as concrete or the like. The fastening point according to the invention can, however, also be mounted on conventional wooden sleepers serving as a substrate.

The rails fastened by means of the components and fastening points 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.

Fastening points of the type in question here or systems comprising the components in question here for producing such fastening points are known in many variants. Examples of such systems are shown in the brochures published by the applicant, which can be found, for example, at the URL http://www.vossloh-fastening-systems.com/de/produkte_2015/anwendungsgebiete/ conventional_rail / conventional_rail_1.html are available for download. Examples include the brochure "System W 41 U Highly elastic rail fastening, highly elastic rail fastening for high speed and main line - the universal solution for ballast superstructure with beadless concrete sleeper", as of 09/2014, the brochure "System W21 - Highly elastic rail fixing for high speed and main line - the modern solution for ballasted superstructures with concrete sleepers ", status 02/2015 or the brochure" System 300 Highly elastic rail fastening for high speed and main line - the proven solution for slab tracks ", status 02/2015.

The well-known rail fastening systems (see for example also WO 2006/005543 A1 and the other patent publications mentioned below) and rail fastening points produced therefrom accordingly each typically comprise a guide plate as the components from which they are assembled (see for example WO 2010/091725 A1 ), which is provided for laterally guiding the rail, a W-shaped tension clamp intended to be placed on the guide plate (see for example WO 2012/059374 A1 ) and a clamping element (see for example WO 2014/029705 A1 ), which is intended to brace the tension clamp against the ground (see for example WO 2006/005543 A1 ).

For these basic components of rail fastening systems, 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 that occur when a rail vehicle passes over the rail over a large area, elastic intermediate layers (see for example WO 2005/010277 A1 ), which are also placed under the rail or the other plate-shaped components of the system to ensure a certain flexibility of the rail in the respective fastening point formed from the system in the direction of gravity, and isolator elements (see for example WO 2015/051 841 A1 ), which is typically placed between the spring element and the foot of the rail to be fastened in order to ensure optimized electrical insulation from the ground.

The W- or ω-shaped tension clamps are usually in one piece and bent from a spring steel wire in one go. They have a usually V- or U-shaped central section, which has two legs aligned parallel to one another. These legs delimit a free space between them through which the respective tensioning means, typically a sleeper screw or a screw bolt, is guided with its shaft into the ground. At one end, the legs are usually connected to one another via a base section which points towards the front of the tensioning clamp assigned to the rail. On the other hand, a torsion section is typically formed on the respective other end of the limbs of the middle section, which, in a laterally outward direction, extends from the respectively assigned limb of the middle section.

The torsion sections are bent in the direction of the underside of the tension clamp so that the spring element can be supported in use in the area of the torsion sections in a support zone formed on the respective torsion section on a contact surface on the upper side of the component carrying the spring element, for example a guide plate , is trained. At their end facing away from the central section, the torsion sections each merge into a holding arm which, when viewed from the side, is typically arched in the direction of the upper side of the tensioning clamp and, as viewed from above, is directed toward the front of the rail to be fastened. The free end sections of the holding arms typically point in the direction of the central section. With these end sections is the tension clamp supported in use on the foot of the rail to be fastened.

Support zones are formed on the underside of the end sections with which the end sections rest on the rail foot during use. In the tension clamps known from practice, the support zones of the holding arms and the torsion sections regularly lie on a straight line that is essentially parallel to the axis of symmetry of the tension clamp.

An example of a tension clamp formed in the above, used in practice and designated as "Skl15" is described in the above-mentioned brochure "System 300 highly elastic rail fastening for high-speed and mainline railways - the proven solution for slab tracks".

Via the shape of the holding arms and the shape and orientation of their end sections, the resilient resilience and the associated hold-down force exerted on the rail via the holding arms can be adapted to the requirements and loads that arise in practical use. In the same way, the spring behavior of the tension clamp can be influenced by the shape of the torsion sections and the middle section and the transition sections that may be present between the middle section and the torsion sections and between the torsion sections and the holding arms.

The guide plates usually have shaped elements on their upper side, on which the spring element to be arranged on the respective guide plate is guided in such a way that it maintains its position during use even under the loads that occur in practice. For example, for this purpose, throat-like depressions, in which the torsion sections of the spring element sit during use, or a central web on which the central loop is guided and can be formed on the upper side of the guide plate is supported.

It has been found that the service life of tension clamps depends crucially on their vibration behavior. It is known that tension clamps usually have several natural frequencies.

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 errors on the rail or on the wheels of the rail vehicles can lead to excessive resonance here. If these are close to one of the natural frequencies of the tension clamp, there is a dramatic increase in the oscillation amplitude, particularly in the area of the retaining arms of the tension clamp. The consequence is a premature, sudden failure of the tension clamp due to a break, which typically occurs in the area of its torsion sections or in the transition area of the holding arms to the torsion sections.

An article by Maximilian Steiger published in the magazine EI - Der Eisenbahningenieur, August 2016, page 25 ff., Reports on studies to optimize the dynamic behavior of rail fastenings. As a result of these investigations, three measures to avoid damage to rail fastenings as a result of resonances have been proposed.

The first of the proposed measures consists in arranging additional vibration-damping elements on the tension clamp. These, for example, disk-like or hose-like additional elements should be arranged in particular in the area of the holding arms. However, the investigation has also shown that such vibration absorbers are highly effective, but prone to destruction, so that the article comes to the conclusion that the practical usability of such absorbers is questionable.

As a second measure, an enlargement of the support surfaces provided for the tension clamp on the respective guide plate has been proposed in the article. The investigation has shown that the natural frequencies of the tension clamps can be increased by increasing the support so that they are outside the range in which excitation typically occurs in practice. In practice, however, the relative movements that the tension clamp and the guide plate inevitably execute when driving over the rail guided laterally by the guide plate and held down by the tension clamp as a result of the inevitable horizontal and vertical movements of the rail proved to be problematic. These movements resulted in increased wear in the area of the widened supports, which calls into question the overall feasibility of the proposed widening of the supports.

Finally, as a third measure, a change in the geometry of the tension clamp itself has been proposed in the article. This measure is also aimed at increasing the natural frequency of the tension clamp to a range outside of the excitation that occurs in practice. The shape of the holding arms and the distance between the holding arms and the so-called "tilt axis" of the holding arms have been recognized as a critical design feature. In this context, the straight lines that connect the center of the zone, with which the respective holding arm is supported at its free end on the rail foot during use, and the center of the zone in which the respective holding arm with its other end is supported on the guide plate. This zone is typically in the area of the torsion section that is assigned to the respective holding arm. By reducing the distance between the arch described by the holding arms and the tilt axis, i.e. reducing the height of the arch above the guide plate, the natural frequencies could in turn be increased sufficiently.

However, goes with the reduction in geometry and especially the Arch height of the holding arms is accompanied by a fundamental change in the spring properties. This can go so far that the tension clamp is no longer optimally usable for the respective purpose or no longer optimally meets the requirements placed on it with regard to its elastic behavior.

Against this background, the task has been set to name practical measures for the design of a single or several interacting components for a rail fastening point with the aim of maximizing the service life of the overall system formed from the components or of its individual components.

To solve this problem, the invention proposes the design of a tension clamp specified in claim 1.

Advantageous refinements of the invention are specified in the dependent claims and, like the general inventive concept, are explained in detail below.

A measure essential to the invention and particularly effective with regard to the problem dealt with here to improve the vibration behavior of the tensioning clamp itself consists in the zone with which the holding arm in question rests on the rail foot in use for each of the holding arms of the tensioning clamp shift so that the natural frequency is shifted to a range in which there is no longer any vibration excitation in practical use.

• einen schlaufenförmigen Mittelabschnitt, der zwei Schenkel und einen die Schenkel miteinander verbindenden Basisabschnitt aufweist, wobe eine freie Stirnseite des Basisabschnitts zu einer Vorderseite der Spannklemme, eine freie Oberseite des Mittelabschnitts zu einer Oberseite der Spannklemme und die Schenkel des Mittelabschnitts mit ihren vom Basisabschnitt abgewandten Enden einer Rückseite der Spannklemme gewandt sind,
• zwei Torsionsabschnitte, von denen jeweils einer an das von dem Basisabschnitt abgewandte Ende eines der Schenkel des Mittelabschnitts angeschlossen ist, wobei die Torsionsabschnitte ausgehend von dem ihnen jeweils zugeordneten Schenkel jeweils seitlich nach außen wegführen und an ihrer Unterseite eine Stützzone aufweisen, mit der die Spannklemme im Gebrauch auf dem sie tragenden Bauteil abgestützt ist, und
  • zwei Haltearme, von denen jeweils einer an das vom zugeordneten Schenkel des Mittelabschnitts abgewandte Ende eines der Torsionsabschnitte angeschlossen ist, wobei die Haltearme in Richtung der Vorderseite der Spannklemme verlaufen und jeweils einen zur Oberseite der Spannklemme hin gewölbten Federabschnitt sowie einen sich daran anschließenden, an einem freien Ende des Haltearms endenden Stützabschnitt aufweisen, der an seiner Unterseite eine Stützzone besitzt, mit der sich der betreffende Haltearm im Gebrauch auf dem Fuß der zu befestigenden Schiene abstützt, wobei die Stützabschnitte der Haltearme jeweils in Bezug auf den Mittelabschnitt der Spannklemme seitlich nach außen weisen.

For this purpose, the invention proposes a tension clamp for elastically holding down a rail for rail vehicles that have one foot and one on the foot standing web and a rail head carried by the web includes, in front of which in a manner known per se

• a loop-shaped middle section which has two legs and a base section connecting the legs to one another, with a free end face of the base section facing a front side of the tensioning clamp, a free top side of the center section facing an upper side of the tensioning clamp and the legs of the center section with their ends facing away from the base section Facing the rear of the tension clamp,
• two torsion sections, one of which is connected to the end of one of the legs of the middle section facing away from the base section, the torsion sections each extending laterally outward from the leg assigned to them and having a support zone on their underside with which the tension clamp is Use on which it is supported structural component, and
  • two holding arms, one of which is connected to the end of one of the torsion sections facing away from the associated leg of the central section, the holding arms extending in the direction of the front of the tensioning clamp and each having a spring section curved towards the top of the tensioning clamp and an adjoining spring section on one have free end of the holding arm ending support section, which has a support zone on its underside with which the holding arm in question is supported on the foot of the rail to be fastened during use, the support sections of the holding arms each pointing laterally outward with respect to the central section of the tensioning clamp .

According to the invention, the support zones of the support sections of the holding arms are each punctiform, and, seen in a plan view from above of the tension clamp, the straight lines, each a Center of the support zones of the support sections of the holding arms with a center of the support zone of the dem connect the respective holding arm associated torsion section, cut in an area located on the back of the tension clamp.

Surprisingly, it has been shown that in a tension clamp according to the invention, the support zones of the support sections of the holding arms and of the torsion section to which the respective holding arm is connected no longer lie on a parallel to the axis of symmetry of the tension clamp, but on a straight line that coincides with this The axis of symmetry includes an acute angle tapering towards the rear of the tension clamp, the natural frequencies of the tension clamp can effectively be increased to such an extent that they are well outside the excitation frequencies that occur in practical use. The invention significantly improves the durability of the tension clamp without this leading to a significant change in the spring behavior. The invention thus eliminates the problems that have arisen in previous practice, without the need for a fundamental redesign of the components of a rail fastening system.

Of course, the invention does not preclude the implementation of an optimized dynamic behavior of the measures in a tension clamp according to the invention in order to achieve a further optimized vibration behavior. These include, in particular, reducing the height of the bend of the holding arms above the contact surface on which the tension clamp is mounted, and increasing the support zones with which the support sections of the holding arms sit on the rail foot during use.

The straight lines running through the centers of the support zones of the mutually associated support sections and torsion sections, viewed in plan view of the tension clamp, preferably close an angle of at least 60 °, in particular more than 60 °, or at least 90 °, in particular more than 90 °, in order to produce the greatest possible distance between the natural frequencies of the tension clamp and a possible excitation frequency. With regard to the spring action of the tension clamp, it has proven to be advantageous if the angle enclosed between the straight lines in a plan view of the tension clamp is a maximum of 120 °, in particular less than 120 °.

To shift the natural frequencies of a tension clamp according to the invention, the selected alignment of the holding arms can also contribute as an optional design element. With regard to the desired displacement of the natural frequency, it can be expedient if, viewed in plan view of the tension clamp, the holding arms, starting from the torsion section assigned to them, extend outwardly away from the central section. In other cases there is surprisingly an optimized shift of the natural frequency when the holding arms, again seen in plan view of the tension clamp, extend inwards from the torsion section assigned to them in the direction of the base section of the central section. This applies in particular when the holding arms, also seen in plan view, each run in a straight line at least over a partial area of the length of their spring sections. With regard to the vibration behavior of the tension clamp, this configuration allows favorable radii at the transition from the legs of the central section to the torsion section connected to it and from the torsion sections to the holding arm connected to them.

With regard to the manufacturability and durability of a tension clamp according to the invention, it also proves to be advantageous if, likewise optionally, the spring section of the holding arms merges into the associated support section in a jump-free curve.

A tension clamp according to the invention can further contribute to the durability and optimal spring behavior, if, in turn optionally, as seen in a plan view of the tension clamp, the support zones of the holding arms protrude in relation to the free end face of the base section of the central section in the direction of the front side of the tension clamp.

An oscillation behavior of tension clamps shaped according to the invention, which is particularly well adapted to the conditions that arise in practice, occurs when, for the distance AS measured parallel to the axis of symmetry of the tension clamp, between the center of the support zones of the holding arms and the intersection of the straight lines, each of which is the center of the Connect the support zones of the holding arms to the center of the support zone of the torsion section assigned to the respective holding arm, and the following applies to the distance AG, which is also measured parallel to the axis of symmetry, between the support zones of the holding arms and the centers of the support zones of the torsion sections: $$1.2\times \mathrm{AG}\le \mathrm{AS}\le 1.8\mathrm{AG}.$$

It has proven to be particularly practical when: $$1.3\times \mathrm{AG}\le \mathrm{AS}\le 1.7\mathrm{AG}.$$

In accordance with the above explanations, an example of a fastening point in which a rail for a rail vehicle comprising a foot, a web standing on the foot and a rail head carried by the web is fastened to a base, has one acting against the lateral edge of the foot of the rail Guide plate for laterally guiding the rail and a tensioning clamp positioned on the guide plate, which is supported with the free end portions of its retaining arms on the foot of the rail in order to exert an elastic hold-down force on the rail. The tension clamp according to the invention is designed for example.

To brace the tension clamp, a fastening point can be a tensioning element, such as a tensioning element, in a manner known per se Sleeper screw or a sleeper bolt, by means of which the tension clamp is braced against the ground. The tensioning element in question is typically guided through the space delimited between the legs of the central section of the tensioning clamp and through an opening in the guide plate below it into the ground, where it is anchored. The anchoring can take place in a known manner by means of a dowel embedded in the ground or by another suitable fastening.

To protect the tension clamp installed in a fastening point for a rail of the type in question here, an insulating element is arranged between the end sections of the retaining arms of the tension clamp and the rail foot, which isolates the tension clamp electrically from the rail foot and at least partially consists of one cushioning or resilient material. For example, the insulator can be designed as a sandwich element, in which electrically insulating layers are combined with damping or elastic layers in order to provide the required electrical insulation on the one hand and vibrational separation of the rail from the tension clamp on the one hand, with sufficient resistance to the hold-down forces applied by the tensioning clamp reach. The measures mentioned here, relating to the insulating element, in themselves, regardless of the design features presented above, contribute to improving the durability of the tension clamp used in a rail fastening point, but of course have a particularly advantageous effect when designing a fastening point.

Another component that is regularly used in fastening points of the type in question is an elastic intermediate layer, which is usually arranged between the rail foot and the ground in order to give the support of the rail a certain flexibility in the direction of gravity. By adapting the damping behavior of the elastic intermediate layer to the in Adjusting the excitation frequencies occurring in practice can also help to avoid excessive excitation of the tension clamp in the range of its natural frequencies.

Fig. 1

eine erfindungsgemäße Spannklemme in Draufsicht von oben;

Fig. 2

die Spannklemme gemäß Fig. 1 in einer perspektivischen Ansicht von ihrer Vorderseite her;

Fig. 3

die Spannklemme gemäß Fig. 1 und 2 in seitlicher Ansicht;

Fig. 4

eine erfindungsgemäße zweite Spannklemme in Draufsicht von oben;

Fig. 5

die Spannklemme gemäß Fig. 4 in einer perspektivischen Ansicht von ihrer Vorderseite her;

Fig. 6

die Spannklemme gemäß Fig. 4 und 5 in einer Ansicht von ihrer Rückseite her;

Fig. 7

die Spannklemme gemäß den Figuren 4 - 6 in seitlicher Ansicht;

Fig. 8

ein Diagramm mit für eine konventionelle und die in den Figuren 4 - 7 dargestellte Spannklemme ermittelten Kraft-Weg-Kennlinien.

The invention is explained in more detail below with the aid of a drawing showing exemplary embodiments. They each show schematically:

Fig. 1

a tension clamp according to the invention in a plan view from above;

Fig. 2

the tension clamp according to Fig. 1 in a perspective view from its front side;

Fig. 3

the tension clamp according to Fig. 1 and 2 in side view;

Fig. 4

a second tension clamp according to the invention in a plan view from above;

Fig. 5

the tension clamp according to Fig. 4 in a perspective view from its front side;

Fig. 6

the tension clamp according to Fig. 4 and 5 in a view from its rear side;

Fig. 7

the tension clamp according to the Figures 4 - 6 in side view;

Fig. 8

a diagram with for a conventional one and the one in the Figures 4 - 7 The tension clamp shown determined the force-displacement characteristics.

The invention, in the Figures 1 - 3 The tension clamp 1 shown, bent in one piece from a spring wire with a circular cross section, has a U-shaped central section 2 with a curved base section 3 assigned to the front side V of the tension clamp and on it connected straight shaped legs 4.5. On the upper side of the legs 4, 5 of the central section 2 associated with the top O of the tension clamp 1, flattened contact surfaces 6, 7 are provided on which a sleeper screw, not shown here, serves as a tensioning element for tensioning the tension clamp 1 with its screw head.

At their ends facing away from the base section 3 and pointing towards the rear side R of the tensioning clamp 1, the legs 4, 5 of the central section 2 each merge into a torsion section 8, 9 of the tensioning clamp 1. The torsion sections 8, 9 are each bent in the direction of the underside U of the tensioning clamp 1 and lead laterally outwardly away from the respectively assigned leg 4, 5. On their underside, the torsion sections 8, 9 each have a support zone 10, 11 with which they sit on a support surface of a guide plate during use.

A holding arm 12, 13 is connected to each end of the torsion sections 8, 9 facing away from the middle section 2. The retaining arms 12, 13 are arched in the area of their spring sections 14, 15 each in the direction of the upper side O of the tensioning clamp 1 and, starting from the respective torsion section 8, 9, run in the direction of the front side V of the tensioning clamp 1. They are oriented so that seen from above in plan view ( Fig. 1 ) the distance of the holding arms 12, 13 measured parallel to the connecting straight line G between the centers Z10, Z11 of the support zones 10, 11 starting from the torsion sections 8, 9 in each case expanded.

At their free ends 16, 17, the holding arms 12, 13 each end in a support section 18, 19 adjoining their respective spring sections 14, 15, with which the holding arm 12, 13 in the use state on the foot of the not shown here, in the respective rail fastening point to be fastened rail sits. On the underside of the support sections 18, 19 assigned to the underside U of the tensioning clamp 1, punctiform support zones 20, 21 are formed for this purpose at the ends 16, 17 of the holding arms 12, 13.

The support sections 18, 19 are shaped in a jump-free curve, starting from the respective spring section 14, 15 pointing laterally outward from the central section 2, so that they are tangentially clinging to a straight line aligned parallel to the connecting straight line G. The length of the holding arms 12, 13 is dimensioned such that the point-like support zones 20, 21 are seen from above in a plan view ( Fig. 1 ) in the direction of the front side V of the tension clamp 1 in front of the base section 3 of the middle section 2.

As a result of the outward-facing arrangement of the support sections 18, 19 and the corresponding laterally external point-like support zones 20, 21 of the holding arms 12, 13 are the connecting straight lines G1, G2, which on the one hand (connecting straight line G1) the center Z10 of the support zone 10 of the torsion section 8 with the point-like support zone 20, which is itself its center, of the holding arm 12 connected to the torsion section 8, and on the other hand (connecting straight line G2) the center Z11 of the support zone 11 of the torsion section 9 with the support zone 21 of the at the point-like and thus also itself representing its center Connecting the torsion section 9 connected holding arm 13, arranged at an acute angle ß1 with respect to the axis of symmetry S of the tensioning clamp 1 and include an angle ß2 of approximately 70 ° between them. Accordingly, they intersect in plan view from above ( Fig. 1 ) viewed at an intersection SG located behind the rear side R of the tension clamp 1.

The distance AS measured parallel to the axis of symmetry S between the punctiform support zones 20, 21 of the holding arms 12, 13, which themselves form their center, on the one hand and the point of intersection SG, on the other hand, corresponds to approximately 1.5 times the distance AG of the also measured parallel to the axis of symmetry S. punctiform support zones 20,21 from the centers Z10, Z11 of the support zones 10,11 of the torsion sections 8,9. In practice, the distance AG can be, for example, approx. 100 mm and the distance AS approx. 150 mm, the distance AS also being in the range of, for example, 130 mm can be varied up to 170 mm if this is appropriate with regard to the setting of the natural frequencies or due to structural conditions.

Practical tests have shown that the tension clamp 1 compared to a conventionally shaped, in the Figures 4 and 5 has shown tension clamp 101 by at least 50% increased natural frequencies. These are so high that there is no excitation of the tension clamp 1 in the range of its natural frequencies even under unfavorable conditions of use, such as those that may exist in tunnels or on bridges, for example.

The also according to the invention, in the Figures 4 - 7 The tension clamp 101 shown, also made from a spring wire with a circular cross-section, is bent in one piece and has, like the tension clamp 1, a U-shaped central section 102 with a curved base section 103 assigned to the front side V of the tension clamp and straight-shaped legs 104, 105 connected to it. On the upper side of the legs 104, 105 of the central section 102 associated with the upper side O of the tension clamp 101, flattened contact surfaces 106, 107 are provided, on which a sleeper screw, not shown here, serves as a tensioning element for tensioning the tension clamp 101 with its screw head.

At their ends facing away from the base section 103 and facing the rear side R of the tension clamp 101, the legs 104, 105 of the central section 102 each merge into a torsion section 108, 109 of the tension clamp 101. On their underside, the torsion sections 108, 109 each have a support zone 110, 111 with which they sit on a support surface of a guide plate during use.

The torsion sections 108, 109 are each bent in the direction of the underside U of the tensioning clamp 101 and lead laterally outwardly away from the respectively assigned leg 104, 105. Based on that respective legs 104,105 the respective torsion section 108,109 leads in a narrower arc than in the tension clamp 1 first in the direction of the underside U of the tension clamp 101 and then in a further arc, which is also narrower than the corresponding arc in the tension clamp 1 to the outside. This is followed by an area of the respective torsion section 108, 109 that is directed laterally away from the associated leg 104, 105 and which, seen in plan view ( Fig. 4 ) is longer than the corresponding area of the tension clamp 1. This area is followed by a further arc 108 ', 109', via which the torsion sections 108, 109 merge into the holding arm 112, 113 connected to them. The radius of curvature of these arcs 108 ', 109' is, viewed in plan view ( Fig. 4 ) larger than the corresponding arc of the tension clamp 1 and extends over a larger angular range than with the tension clamp 1. In this way, holding arms 112, 113 of the tension clamp 101 are, starting from their connection to the respectively assigned torsion section 108, 109 in the direction of the freely protruding base section 103 of the middle section 102 of the tension clamp 101 aligned. The holding arms 112, 113, viewed in plan view ( Fig. 4 ) an area 112 ', 113' in which they are straight shaped. When viewed from above ( Fig. 4 ) A straight line is placed in each of the areas 112 ', 113' coaxially to the longitudinal axis of the areas 112 ', 113', then these straight lines intersect at a point that lies on the front side V of the tension clamp 101 and the axis of symmetry S of the tension clamp 101. At the same time, the holding arms 112, 113 in the area of their spring sections 114, 115 are each arched in the direction of the top O of the tension clamp 1.

At their free ends 116,117, the holding arms 112,113 each end in a support section 118,119 adjoining their respective spring section 114,115, with which the respective holding arm 112,113 sits on the foot of the rail, not shown here, to be fastened at the respective rail fastening point. On the underside U of the tension clamp 101 associated underside of the support sections 118, 119 are formed on the ends 116, 117 of the holding arms 112, 113 in each case punctiform support zones 120, 121.

The support sections 118, 119 are shaped in a jump-free curve, starting from the respective spring section 114, 115 and pointing laterally outward from the central section 102, in such a way that they are tangential to a straight line aligned parallel to the connecting straight line G. The length of the retaining arms 112, 113 is dimensioned so that the point-like support zones 120, 121 viewed from above in a plan view ( Fig. 4 ) in the direction of the front side V of the tension clamp 101 in front of the base section 103 of the middle section 102.

As a result of the outward-facing arrangement of the support sections 118, 119 and the corresponding laterally external point-shaped support zones 120, 121 of the holding arms 112, 113, the connecting straight lines G1, G2, which on the one hand (connecting straight line G1) the center Z110 of the support zone 110 of the torsion section 108 with the point-shaped and thus itself The center of the support zone 120 of the holding arm 112 connected to the torsion section 108 and on the other hand (connecting line G2) connect the center Z111 of the support zone 111 of the torsion section 109 with the support zone 121 of the holding arm 113 connected to the torsion section 109, which is also point-like and thus also represents its center , arranged at an acute angle ß1 with respect to the axis of symmetry S of the tension clamp 101 and enclose an angle ß2 of approximately 60 ° between them. Accordingly, they intersect in plan view from above ( Fig. 4 ) viewed in an intersection point SG located behind the rear side R of the tension clamp 101.

The distance AS, measured parallel to the axis of symmetry S, between the punctiform support zones 120, 121, which themselves form their center, of the holding arms 112, 113 on the one hand, and the point of intersection SG, on the other hand, corresponds approximately 1.7 times the distance AG, also measured parallel to the axis of symmetry S, of the punctiform support zones 120, 121 from the centers Z110, Z111 of the support zones 110, 111 of the torsion sections 108, 109. In practice, the distance AG can for example be about 100 mm and the distance AS about 150 mm, the distance AS can also be varied in the range of, for example 130 mm to 170 mm, if this is with regard to the setting of the Natural frequencies or due to structural conditions is appropriate.

Practical tests have shown that the tension clamp 101 increased by 50% compared to a conventionally shaped tension clamp 101 known under the designation Skl15 and described in the above-mentioned brochure "System 300 Highly elastic rail fastening for high speed and mainline railways - the proven solution for slab tracks" Has natural frequency.

The force-displacement characteristics of the second loading and unloading determined in the tests are in Fig. 8 shown, the characteristic curve of the conventional tension clamp Skl15 being shown as a solid line and the characteristic curve of the tension clamp 101 according to the invention as a dashed line.

It can be seen that the characteristic curve of the tension clamp 101 according to the invention has a flatter slope, which has a favorable effect on the fatigue strength of the tension clamp 101. As a result, the tension clamp 101 has not only an improved natural frequency behavior compared to the conventional Skl15, but also an improved fatigue strength. That is, the tension clamp 101 according to the invention can withstand significantly higher deformations than the conventional tension clamp Skl15.

The characteristic values "natural frequency" determined in the tests for the conventional tension clamp Skl15 and the tension clamp 101 according to the invention, Vertical fatigue strength and the gradient of the characteristic curve of the tension clamps are entered in Table 1.

To determine the natural frequency, modal analyzes were first carried out using the finite element method "FEM" and the results obtained were then verified by measurements on the test bench and on the track.

The vertical fatigue strength was determined using the DBS918127 standard of Deutsche Bahn AG, June 2010 (DB standard), Chapter 5.3 "Vertical fatigue strength".

The natural frequency determined for the tension clamp 101 is so high that there is no excitation of the tension clamp 101 in the range of its natural frequencies even under unfavorable conditions of use, such as may exist for example in tunnels or on bridges. Table 1 SKL15 Tension clamp 101 First natural frequency 500 - 600 Hz 900-1000 Hz Vertical fatigue strength 3 mm at least 5 mm Slope of the characteristic 0.7 - 0.8 mm / kN 0.3 - 0.4 mm / kN

REFERENCE MARK

1.101

Tension clamp

2.102

Middle section of the tension clamp 1,101

3.103

Base section of the middle section 2,102

4,5,104,105

Legs of the middle section 2,102

6,7,106,107

Contact surfaces of the legs 4,5,104,105

8,9,108,109

Torsion sections of the tension clamp 1,101

108 ', 109'

Arch in the area of the transition between the respective holding arm 112, 113 and the associated torsion section 108, 109

10,11,110,111

Support zones of the torsion sections 8,9,108,109

12,13,112,113

Holding arms of the tension clamp 1, 101

112'113 '

just aligned area of the holder arms 112,113

14,15,114,115

Spring sections of the holding arms 12,13,112,113

16,17,116,117

free ends of the holding arms 12,13,112,113

18,19,118,119

Support sections of the holding arms 12,13,112,113

20,21,120,121

punctiform support zones (= center of the support zones 20,21,120,121)

ß1, ß2

angle

AG, AS

distances

G, G1, G2

Connecting line

O

Top of the tension clamps 1,101

R.

Rear of the tension clamp 1,101

S.

Axis of symmetry of the tension clamp 1.101

SG

Intersection

U

Underside of the tension clamp 1,101

V

Front of the tension clamp 1,101

Z10, Z11, Z110, Z111

Centers of the support zones 10,11,110,111

Claims (10)

1. Tension clamp for elastically holding down a rail for rail vehicles, the rail comprising a foot, a web that is supported on the foot and a rail head carried by the web , the tensioning clamp having

   - a loop-shaped central section (2;102), with two legs (4,5;104,105) and a base section (3; 103) that connects the legs (4,5;104,105) to one another, wherein a free end face of the base section (3;103) faces a front face (V) of the tension clamp (1;101), a free upper face of the central section (2;102) faces an upper face (O) of the tension clamp (1;101) and the legs (4,5;104,105) of the central section face with their ends, which face away from the base section (3;103), a rear face (R) of the tension clamp (1;101),

   - two torsional sections (8, 9; 108, 109), one of which in each case is connected to that end of one of the legs (4, 5; 104, 105) of the central section (2; 102) that faces away from the base section (3; 103), wherein the torsional sections (8, 9; 108, 109) lead away laterally in an outwards direction in each case starting from the leg (4,5; 104, 105) that is allocated to them respectively and wherein the torsional sections (8, 9, 108, 109) have a supporting zone (10, 11; 110, 111) on their lower face by means of which the tension clamp (1; 101) is supported on the component that bears them during use, and

   - two supporting arms (12, 13; 112, 113), one of which in each case is connected to the end of one of the torsional sections (8, 9; 108, 109) that faces away from the allocated leg (4, 5; 104, 105) of the central section (2; 102), wherein the supporting arms (12, 13; 112, 113) run in the direction of the front face (V) of the tension clamp (1; 101) and in each case have a spring section (14, 15; 114, 115) curved towards the upper face (O) of the tension clamp (1; 101) and a support section (18, 19; 118, 119) that ends at a free end of the supporting arm (12, 13; 112, 113), the lower face of which support section has a supporting zone (20,21;120,121) by means of which the supporting arm (12, 13;112, 113) in question is supported on the foot of the rail to be fastened during use, wherein the supporting zones support sections (18, 19; 118, 119) of the supporting arms (12, 13; 112, 113) each point laterally outward relative to the central section (2; 102) of the tension clamp (1; 101),

   characterized in that the supporting zones (20,21; 120,121) of the support sections (18, 19; 118, 119) of the supporting arms (12, 13; 112, 113) are in each case designed punctiform, and in that, when the tension clamp (1; 101) is viewed from above, the straight lines (G1, G2) that connect a center of the supporting zones (20, 21; 120, 121) of the support sections (18, 19; 118, 119) of the supporting arms (12, 13; 112, 113) to a center (Z10, Z11; Z110, Z111) of the supporting zone (10, 11; 110, 111) of the torsional section (8, 9; 108, 109) allocated to the respective supporting arm (12, 13; 112, 113) intersect in an area located on the rear face (R) of the tension clamp (1; 101).
2. Tension clamp according to Claim 1, characterized in that the angle (β2) enclosed between the straight lines (G1, G2) when the tension clamp is viewed from above (1; 101) is at least 60°, in particular at least 90°.
3. Tension clamp according to any one of the preceding claims, characterized in that the angle (β2) enclosed between the straight lines (G1, G2) when the tension clamp is viewed from above (1; 101) is a maximum of 120°.
4. Tension clamp according to any one of the preceding claims, characterized in that the supporting arm (12, 13) runs in an outwards direction from the central section (2) starting from the torsion section (8, 9) allocated to it when the tension clamp (1) is viewed from above.
5. Tension clamp according to any one of Claims 1 to 3, characterized in that the supporting arm (112, 113) runs in an inwards direction in the direction of the base section (103) of the central section (102) starting from the torsion section (108, 109) allocated to it when the tension clamp (101) is viewed from above.
6. Tension clamp according to Claim 5, characterized in that the supporting arm (112, 113) runs in a straight line over at least part of the length of its spring sections (114, 115).
7. Tension clamp according to any one of the preceding claims, characterized in that in the case of the supporting arms (12, 13; 112, 113) the spring section (14, 15; 114, 115) transitions into a continuous curved line in the allocated support section (18, 19; 118, 119).
8. Tension clamp according to any one of the preceding claims, characterized in that when the tension clamp (1; 101) is viewed from above, the supporting zones (20, 21; 120, 121) of the supporting arms (12, 13; 112, 113) protrude relative to the free front face of the base section (3; 103) of the central section (2; 102) in the direction of the front face (V) of the tension clamp (1; 101).
9. Tension clamp according to any one of the preceding claims, characterized in that for the distance AS measured parallel to the symmetrical axis (S) of the tension clamp (1; 101) between the center of the supporting zones (20, 21; 120, 121) of the supporting arms (12, 13; 112, 113) and the point of intersection (SG) of the straight lines (G1, G2) which connect the center of the supporting zones (20, 21; 120, 121) of the supporting arms (12, 13; 112, 113) respectively to the center (Z10, Z11; Z110, Z111) of the support zones (10, 11; 110, 111) of the torsional section (8, 9; 108, 109) allocated to the respective supporting arm (12, 13; 112, 113) and for the distance AG that is also measured parallel to the symmetrical axis (S) between the supporting zones (20, 21; 120, 121) of the supporting arms and the centers (Z10, Z11; Z110, Z111) of the supporting zones (10, 11; 110, 111) of the torsional sections (8, 9; 108, 109), the following applies: $$1.2\times \mathrm{AG}\le \mathrm{AS}\le 1.8\mathrm{AG}.$$

   
10. Tension clamp according to Claim 7, characterized in that the following applies for the distance AG and the distance AS: $$1.3\times \mathrm{AG}\le \mathrm{AS}\le 1.7\mathrm{AG}.$$

    

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