WO2011116756A2

WO2011116756A2 - Tension clamp

Info

Publication number: WO2011116756A2
Application number: PCT/DE2011/000312
Authority: WO
Inventors: Armin Schaffer; Helmut Eisenberg
Original assignee: Thyssenkrupp Gft Gleistechnik Gmbh
Priority date: 2010-03-26
Filing date: 2011-03-25
Publication date: 2011-09-29
Also published as: DE102010013055A1; WO2011116756A3; EP2553172A2; RU2012143280A; RU2568156C2

Abstract

The invention relates to a tension clamp (2) for fastening rails, comprising a U-shaped center section (20) and limbs (21, 22) extending outwardly. The limbs transition across a torsion section (A) into a curved retaining arm (27, 28), characterized in that the ratio of the curvature-free torsion segment KTS (A) to the lever arm HA (B) fulfills the condition 0.05 < KTS/HA < 0.6.

Description

tension clamp

The invention relates to a tension clamp (tensioning element) for the attachment of rails, with a U-shaped central portion and tapered legs, which pass over a Torsionsabschnitt in a curved extending support arm.

Generic tension clamps are required for fastening railroad tracks on concrete subsurface or thresholds made of wood, steel or concrete. With the help of the tension clamps, the railroad track is permanently held positively on the sleepers with the application of a corresponding clamping force (called down force in the following). Such rail fasteners are known for many decades, preferably for the tension clamp W-shaped bent resilient wire elements are used. To fix the tension clamp, it has a U-shaped middle section with two legs, which is provided for receiving a tensioning screw (for example sleeper screw, hook bolt, anchor bolt, hammer head bolt, etc.). The legs of the U-shaped central portion have a preferably nearly right-angle curvature and a subsequent torsion portion. After the Torsionsabschnitt follows an arcuate course with straight expiring limb ends that come to rest as a support arm on the rail. The free ends of the support arms press the rail or rail foot against the railway sleeper. In order to produce a sufficient hold-down force, the U-shaped middle section is braced by means of a tightening screw or the like, wherein the tightening screw is screwed, for example, into a dowel which is cast directly in a concrete sleeper. Depending on the embodiment of the tension clamp, this can achieve a hold-down force of usually 5.5 to 14 kN, at the same time as a result of the load of the rail support by driving over rail vehicles a durable dynamic travel of min. 1, 4 mm can be realized around the bracing point.

To set the hold-down force, the clamps are biased with a tightening screw, e.g. is screwed into a dowel, e.g. already in the

CONFIRMATION COPY Concrete threshold was embedded in concrete. The hold-down force of the clamps decreases according to the predetermined spring characteristic of the clamp used on the deflection. The clamps available on the market in this case have a relatively steep increase in the spring characteristic, up to a predetermined value, which is always achieved when the middle loop of the clamp for abutment on the guide member (eg angle guide plate to the already resting support arms on the rail Wfp) of the rail comes. At the time of tilting of the rail, when overloaded by lateral forces, for example in tight bends, the force acting on the rail foot due to the anti-tip function increases disproportionately.

As far as railway sleepers are laid in the gravel, the burden of rail transport will largely lead to a deflection of the railway sleepers within the ballast, if under the rail a hard intermediate layer (Zw), with a stiffness of more than 400 N / mm, use. If an elastic intermediate layer is used, this will also have a measurable share of the total deflection of the rail support point. However, as far as a prefabricated infrastructure is used (slab track FF) inevitably eliminates the share of the ballast to the total deflection. For this reason, highly elastic underlay plates are used in the region of the rail supports, which allow a compression of the rail body in the region of the rail support point under load. As soon as the height of the rail foot changes relative to the tensioned tension clamp, this leads to a change in the hold-down force according to the spring characteristic of the tension clamp. The relief of the tension clamp by the deflection of the rail thus results, for. to a lower holding force. This problem is particularly noticeable in a type FF track, where high elasticity intermediate plates (Zwp) are used.

In the field of FF, there is another fundamental issue arising from the technical conditions and requirements for driving dynamics.

To ensure a uniform height level, it is necessary, for example, that the position of the prefabricated concrete sleepers be previously measured and leveled out. Due to manufacturing tolerances of FF this leads to regular Deviations up to several millimeters, which must be compensated eg by correspondingly thick intermediate layers (Zw). The compensation possibility moves in this case partly in sizes of several millimeters (in both the plus and the minus) around the nominal installation position. When using the extreme values, this leads, with the tension clamps available on the market, directly to a strong change in the hold-down force.

Both effects, that is to say dynamic depression from the driving operation and static changes in the rail height position lead either to a temporary shift of the stress ratio or to the fundamental displacement of the stress point on the spring characteristic of the corresponding tension clamp and thus to a negative deviation from the technical design.

The present invention has for its object to keep the occurring fluctuations in the hold-down force as a result of a shift in the altitude of the tension point (force-spring travel diagram) of the rail in the rail base as low as possible.

To achieve the object, it is provided that the ratio of bending-free torsion path KTS to the lever arm HA satisfies the condition 0.05 <KTS / HA <0.6. Further advantageous embodiments will be apparent from the dependent claims.

If the defined ratio of curvature-free torsion distance KTS to lever arm HA is maintained, depending on the structural requirements can be ensured in sufficient form depending on KTS or HA, that the tension clamp has a relatively flat rising spring characteristic, so that the change in clamping force per millimeter travel compared to conventional Clamping is significantly reduced. The length of the curvature-free torsion path KTS is in this case adjusted to the lever arm HA used so far that within the limits shown between 0.05 and 0.6 an optimal characteristic curve is ensured. In this case, it is particularly important that the characteristic runs extremely flat and, for example, due to a lower altitude of the rail foot - relative to tensioned tension clamp - the reduction of the hold down force is much lower than with conventional tension clamps or an unnecessary increase of the preload on the highly elastic bearing is avoided when the rail must be raised in the context of height corrections. As a result, the essential advantage is achieved that, first, the behavior of the rail support point is subject to less fluctuations, and, secondly, above all, the resulting penetration resistance can be kept significantly more constant in the area of the nominal design.

In order to achieve the ratio between the curvature-free torsion path KTS according to the invention to the lever arm HA preferably clamps with a spring constant c <0.6 kN / mm are used. The spring constant results directly from the achievable force effect and the distance c = F / s.

Under a curvature-free torsion path KTS, a maximum radius of the torsion path is defined as 100 <R <°°, preferably 500 <R <°°, due to the existing manufacturing tolerances. In principle, it can not be completely ruled out in the manufacturing process that there is a slight curvature of the torsion portion, which is taken into account with the aforementioned condition in such a way that it starts from an extremely small curvature of the torsion portion.

In an embodiment of the invention, it is provided that the tensioning clamp has a curvature-free torsion path of 15 to 40 mm, preferably 20 to 30 mm. Due to the selected length of the torsion, this significant influence on the characteristic of the tensioning clamp is taken, this torsion distance is in turn in relation to the lever arm, which may be 50 to 200 mm, preferably 100 to 120 mm.

The tension clamp according to the invention is characterized in that there is a shallow rise in the spring characteristic diagram, as a result of which the loss of clamping force per millimeter of travel is markedly reduced. In a further embodiment of the invention it is provided that the support arms are bent so far that the free ends of the support arms are directed in the plan view directed towards the central portion. The outgoing support arms in this case assume a position which is aligned approximately parallel to the course of the rail body, whereby the support arms can be placed with maximum coverage on the rail of the rail.

Thus, the tension clamp has a sufficient spring force, regardless of the characteristic curve is provided that in the untensioned state of the tension clamp of the central portion in a first plane and the support arms are located to this first level in a second plane extending at an angle. This ensures that the support arms rest even in a compression of the rail body in any position on the rail foot. The essential idea of the present invention is that the characteristic is extremely flat and, e.g. due to a lower level of the rail foot - relative to the strained tension clamp - the reduction of the hold down force is much lower than conventional tension clamps or unnecessary increase of the bias on the highly elastic storage is avoided when the rail must be raised in the context of height corrections. As a result, the essential advantage is achieved that, firstly, the behavior of the rail support is subject to less fluctuations and, secondly, above all, the resulting push-through resistance can be kept much more constant in the area of the nominal design.

The invention will be explained again with reference to the figures.

It shows

Fig. 1 in a sectional view, the arrangement of a tension clamp

for fastening a rail body,

Fig. 2 shows three views of a tension clamp according to the invention and Fig. 3 shows the characteristic curve of a conventional tensioning clamp and the tensioning clamp according to the invention.

Figure 1 shows a sectional view of a rail 1, which by means of a tensioning clamp 2 and a clamping screw 3 on a substrate 4, which may for example consist of concrete, is attached. The clamping screw 3 is screwed to achieve a bias of the tension clamp 2, for example, in a dowel 5, which is anchored directly in the ground 4, for example, was poured into the concrete. The clamping screw 3 is in this case in the U-shaped central part of the clamp 2 and pushes this area when tightening down, so that the resulting clamping force (hold-down force) is transmitted to the support arms 6. The support arms 6 are in this case directly on the rail 7, so that the rail 1 is pressed down on the ground 4. Below the rail 1, for example, there is an elastomer 11. Due to a load from the rail traffic is thus possible that the rail 1 can compress using the elastomer 1 1 and is pushed back into the original position.

Figure 2.1 to 2.3 show in three views an inventive embodiment of a tension clamp 2, which has a U-shaped bent central portion 20, wherein the two legs 21, 22 of the central portion 20 have a predefined distance from each other, in such a way that the clamping screw according to FIG 1 between the legs 21, 22 can be placed. The legs 21, 22 are then passed over a curvature 23, 24 in a torsion A, which is designed almost free of curvature. Following the torsion section A is followed by a curved section 25, 26, which in the embodiment shown corresponds to a semicircle or may consist of two quarter circles with a torsion intermediate section without curvature, while the free ends, which are formed as retaining arms 27, 28, straight leak and are provided immediately to rest on the rail 7. The tension clamp 2 is made in one piece from, for example, a round spring steel, which applies the necessary elasticity while generating a high hold-down force. The hold-down force on the rail foot will achieved by the clamping screw 3 is clamped in accordance with Figure 1 and thus the U-shaped central portion 20 is pressed down, which in turn due to a one-sided support of the tension clamp 2 below the torsion A, the tensioning force is transmitted directly to the support arms 27, 28.

According to the invention, the tension clamp 2 is constructed in such a way that the torsion length A and the lever arm B satisfy the condition 0.05 <KTS / HA <0.6, the lever arm being defined by the distance of the neutral fiber of the torsion portion A and the holding arm 27, 28 is given. By maintaining the upper and lower limit 0.05 to 0.6 is achieved here that the spring characteristic curve is formed according to Figure 3 is very flat rising and thus a possible Niederhaltekraftverlust per millimeter travel is kept as low as possible.

The two other views show the present invention tension clamp 2 in a side view with a view of the central portion 20th

FIG. 3 shows the spring characteristic 30 of a tension clamp according to the prior art and the spring characteristic 31 of the newly developed tension clamp 2. The spring tension diagram shows the tension force in relation to the spring travel, with the spring travel in millimeters and the tension force in kN , The characteristic curve 30 shows a typical course of a tensioning clamp with a relatively steep rise to a limit value (starting anti-tilt protection), which leads to a disproportionate increase in the clamping force by the plant of the central portion of the tension clamp on the rail. Decisive, however, is the linear increase in the clamping force, taking into account the spring travel that occurs. Due to the slope of a tension clamp according to the prior art, even with a small change in the spring travel a high change in clamping force recorded while the spring characteristic of the tension clamp 2 according to the invention with a smaller increase in the spring characteristic, taking into account an identical spring deflection a significantly reduced change in clamping force occurs. LIST OF REFERENCE NUMBERS

1 rail

2 tension clamp

3 clamping screw

4 underground

5 dowels

6 holding arm

7 rail foot

8 Sandwich construction 1 1 Elastomer

20 middle section

21 thighs

22 thighs

23 curvature

24 curvature

25 section

26 section

27 holding arm

28 holding arm

30 spring characteristic

31 spring characteristic

A torsion section

B lever arm

Claims

claims

A tensioning clamp (2) for fastening rails (1), having a U-shaped middle section (20) and outgoing legs (21, 22), which via a torsion section (A) into a curved support arm (6, 27, 28), characterized in that the ratio of bending-free torsion path KTS (A) to the lever arm HA (B) satisfies the condition 0.05 <KTS / HA <0.6.

2. tension clamp (2) according to claim 1, characterized in that the spring constant c <0.6 kN / mm.

3. tension clamp (2) according to claim 1 or 2, characterized in that the curvature-free torsion path (A) satisfies the condition 100 <R <°°, preferably 500 <R <°°, where R is an assumed radius of the torsion distance (A) is.

4. tension clamp (2) according to any one of claims 1, 2 or 3, characterized in that the tensioning clamp (2) has a curvature-free torsion path (A) of 15 to 40 mm, preferably 20 to 30 mm.

5. tension clamp (2) according to one of claims 1 to 4, characterized in that the tension clamp (2) has a lever arm (B) of 50 to 200 mm, preferably 100 to 120 mm.

6. tension clamp (2) according to one of claims 1 to 5, characterized in that the tension clamp (2) has a clamping force curve with a shallow rise up to a travel of 20 mm or 35 mm.

7. tension clamp (2) according to one of claims 1 to 6, characterized in that the retaining arms (6, 27, 28) are bent so far that the free ends of the support arms (6, 27, 28) seen in the plan view against the Center section (20) are directed.

8. tension clamp (2) according to one of claims 1 to 7, characterized in that in the untensioned state of the tension clamp (2) the central portion (20) in a first plane and the retaining arms (6, 27, 28) are located to this first level in a second plane extending at an angle.