Clamping spring for holding down a track body element

Abstract

The invention relates to a clamping spring (1) for holding down a track body element, such as a foot of a rail, the clamping spring comprising a U-shaped main portion which has: - a U bend (2); - a first leg (3) located on one side of the U bend (2); and - a second leg (4) located on the other side of the U bend (2). In this clamping spring, a retaining portion (5) curved inward in the shape of a hook and supportable on a hold-down element (12) is formed on the first leg (3), and an end portion (6) bent toward or away from the retaining portion (5) is formed on the second leg (4), the U bend (2) forming a torsion portion so that a hold-down force can be applied to the track body element by means of the bent end portion (6).

Description

[0001] Tension spring for holding down a track element

[0002] The invention relates to a tension spring for holding down a track body element, such as a rail foot of a rail.

[0003] Furthermore, the invention relates to a rail fastening comprising a tension spring according to the invention and a hold-down device which can be fastened adjacent to a rail on a base, in particular a sleeper, ribbed plate or angle guide plate.

[0004] The installation of rails on a track bed is usually carried out using a spring element, usually referred to as a tension spring or tension clamp, and a suitable tensioning element or hold-down device to brace the spring element. This tensioning element or hold-down device is usually a screw, by means of which the spring element is braced against the subsurface so that it exerts the necessary holding forces via the section resting on the rail foot. The bracing can be achieved, for example, by connecting the hold-down device directly to the subsurface, which supports the rail and the fastening system, or by attaching the hold-down device to an additional component, such as a plate, which is then firmly coupled to the subsurface.

[0005] Widely used tension springs are those with the "e" shape and those with a "»" shape. A tension spring with the "e" shape is described, for example, in EP 313325 B1. The "o" shape is described, for example, in DE 3243895 A1. Numerous designs of fastening systems with tension springs are known in which the tension spring can be brought relative to the rail foot and the anchoring parts not only into a precisely defined final assembly position, but also into a secured pre-assembly position. To achieve the pre-assembly position, the tension spring is mounted in such a way that the section intended for holding down the rail foot does not lie on the rail.In this way, railway sleepers can be provided with tension springs arranged in the pre-assembly position and pre-tensioned in the factory, whereby the tension springs can be brought into the final assembly position and tensioned on the construction site after the rail has been laid on, with a certain amount of effort, by shifting them sideways so that the section intended to hold down the rail foot overlaps it and presses it down from above.

[0006] A disadvantage of prior art tension springs is the fact that they are only designed for a single installation direction or type of installation. The installation direction is understood to be the direction in which the tension spring, which is usually already pre-tensioned, is pushed onto the rail foot. The most common tension springs are those designed for transverse installation, i.e. for sliding the tension spring onto the rail at right angles to the longitudinal direction of the rail. With longitudinal installation, however, the tension spring is brought into its final assembly position in the longitudinal direction of the rail. Due to the limited space, installation in the longitudinal direction of the rail is advantageous, for example, for fastening the rails in the area of ​​switches.Conventional tension springs are adapted to their specified installation direction, particularly with regard to the arrangement of areas of different stiffness, and therefore cannot simply be installed in a different direction, although in most cases a different installation direction is not even possible for geometric reasons.

[0007] Other problems with conventional tension springs include breakage and loosening of the tension springs, resulting in a loss of tension force. This loosening occurs particularly in tension springs that are tensioned with a screw.

[0008] Tension springs often break when they are subjected to excessive loads. Conventional rail fastening systems are, at least in some cases, equipped with an overload protection device. The purpose of an overload protection device is to limit the load acting on the tension spring, which is particularly important when the rail is subject to a strong upward and downward movement or a strong tilting movement relative to the sleeper when passing over it.

[0009] The present invention therefore aims to improve a tension spring and a corresponding fastening system so that the aforementioned disadvantages can be overcome. In particular, a tension spring is to be created that can be held down or tensioned both with a screw and without a screw, and that has a high degree of elasticity. The tension spring is to be universally applicable, in particular for holding down rails on open track as well as in the area of ​​switches. Finally, installation and removal are to be made easier, and a secure pre-assembly position is to be enabled.To achieve this object, the invention provides, according to a first aspect, a tension spring comprising a U-shaped main section which has a U-bend, a first leg arranged on one side of the U-bend and a second leg arranged on the other side of the U-bend, wherein a hook-shaped holding section which is bent inwards and can be supported on a hold-down device is formed on the first leg and an end section which is bent towards or away from the holding section is formed on the second leg, wherein the U-bend forms a torsion section so that a hold-down force can be applied to the track body element via the bent end section.

[0010] Because the tension spring, starting from the basic shape of a "U", has a hook-shaped holding section on the first leg of the U-shape and an end section bent towards or away from the holding section on the other leg of the U-shape, an asymmetrical shape is achieved which is easy to manufacture and which allows installation in both the transverse and longitudinal directions. In both the longitudinal and transverse installation, the bent end section forms the area of ​​the tension spring via which the hold-down force is applied to the track element or the rail foot.

[0011] The design of the tension spring according to the invention is similar to that of the "e" shape known from the prior art, with the difference that the end section of the "e" shape has an additional bend. This bend can be designed towards or away from the holding section of the tension spring. The bend preferably runs towards the holding section of the tension spring. According to a preferred design, the bent end section runs at an angle of 80-100°, preferably approximately 90°, to the second leg, whereby this applies both to the design with an end section bent towards the holding section of the tension spring and to the design with an end section bent away from the holding section. The advantages of the bent end section become clear both in longitudinal and transverse installation in interaction with the hold-down device, as explained in more detail below.

[0012] In some embodiments of the invention, the U-shape formed by the U-bend, the first leg, and the second leg also includes configurations in which the first leg is reduced to a minimum, so that the U-bend merges directly into the holding section. In other embodiments, however, the first leg has a certain length, such as a length substantially corresponding to the second leg, and is, in particular, straight.

[0013] The hook-shaped holding section extending from the first leg of the U-shape is used to be held under tension by a hold-down device when a torsional force is exerted by the bent end section on the torsional section formed by the U-bend of the tension spring. The hook-shaped holding section is bent inwards, which means that the hook is bent between the two legs of the U-shape. Preferably, the hook-shaped holding section on the first leg forms the end of the tension spring, i.e. the free end of the area bent into a hook lies between the two legs of the U-shape. In this context, a preferred embodiment provides that the holding section has a free end area which is connected to the first leg via a hook bend and is arranged between the first leg and the second leg.

[0014] According to a preferred embodiment of the invention, a hook bend of the holding section has a substantially 180° bend, so that a free end region of the holding section runs substantially parallel to the first leg, at least in sections. The expression "substantially 180°" means that the angle is 180°, but can also be between 175° and 185°.

[0015] The hold-down force is provided at least partially by a torsional load on the torsion section formed by the U-bend of the tension spring, resulting in a corresponding resilient deflection of the second leg extending from the U-bend to the bent end section. While the second leg thus forms a deflectable spring arm, the remaining part of the tension spring can be designed as flat as possible to minimize the overall height of the tension spring and the material consumption for the tension spring.

[0016] In this context, a preferred embodiment provides that the first leg and the free end region of the holding section provide a flat support surface in the unloaded state. The flat support surface can, for example, serve as a support for the hold-down device, whereby the flat state refers to the unloaded state of the tension spring, since slight twisting of the holding section can occur when the tension spring is tensioned. In this case, the first leg and the free end region of the holding section can, in the unloaded state, lie with their respective central axes, preferably over their entire extent, in a central plane that preferably runs parallel to the flat support surface. The central axis of the corresponding sections is to be understood, for example in the case of a circular cross-section, as the center line or axis passing through the center of the circle.

[0017] However, it can also be provided that the first leg and the holding section lie in the same plane in the unloaded state, or with their respective center axes in the center plane. This also provides a flat support surface and prevents parts of the first leg and the holding section, including the hook bend, from being bent out of said plane.

[0018] The design of the U-bend of the tension spring can also contribute to achieving the flattest possible construction in that the free end region of the holding section, seen in the direction of a longitudinal extension of the free end region, preferably covers the U-bend at least partially, preferably completely.

[0019] In order to ensure sufficient spring travel, however, the bent end section of the tension spring can be deflected out of the said plane when unloaded. A preferred design in this context provides that the bent end section, when unloaded, has a normal distance to the center plane or to the flat support surface. If the entire holding section, including the hook bend, and the first leg lie in the same plane, this means with regard to the overall height of the tension spring that the hook bend and the bent end section, when unloaded, define the maximum overall height of the tension spring, measured normal to the center plane or to the flat support surface. This enables the tension spring to be designed to be extremely flat.

[0020] In particular, the overall height of the tension spring in the unloaded state can correspond to 1.5 to 3 times the diameter of the wire forming the tension spring in the holding section.

[0021] Preferably, an imaginary extension of the bent end section overlaps the hook bend in a plan view. This means that the imaginary extension of the bent end section at least partially overlaps the hook bend in the plan view of the tension spring. For transverse installation of the tension spring, this means that the hook bend lies above the rail foot in the final assembly position and can form an overload protection feature.

[0022] The tension spring conventionally consists of a spring rod and can therefore be manufactured in one piece from a corresponding starting product. It is manufactured by bending an originally straight spring rod multiple times. If, as is preferably provided, the hook-shaped holding section, the U-bend and the bent end section are all bent in the same direction, the tension spring can be manufactured in three bending steps. The hook-shaped holding section is bent in the first step, the U-bend in the second step and the bent end section in the third step. The three bending steps can also be carried out in one circular operation if all three bends occur in the same direction of rotation. These bends can all occur in the same plane, or individual areas can be deflected from the common plane at the same time as the bends.

[0023] The cross-section of the tension spring is preferably circular, although other cross-sectional shapes are also conceivable, such as oval, elliptical or the like.

[0024] Due to the relatively simple geometry of the tension spring according to the invention, its mechanical properties can be easily adapted to specific requirements by varying certain geometric parameters while maintaining the basic shape. For example, the length of the second leg of the U-shape, and thus the length of the lever arm acting on the torsion section, determines the stiffness of the tension spring. The tension, clamping force, and stiffness can be controlled by selecting the thickness of the spring rod. The radius of the U-bend also controls the tension and stiffness of the tension spring.

[0025] In order to be able to exert a holding-down force on the rail foot by tensioning the holding section by means of the hold-down device and the resulting torsional load on the torsional section of the tension spring via the bent end section, it is preferably provided that the second leg, in the unloaded state, has a normal distance from the center plane or from the flat support surface which continuously increases in the direction of the bent end section.

[0026] This means in particular that the second leg, in the unloaded state, runs at an acute angle relative to the central plane or to the flat support surface. The acute angle can be between 5° and 20°. Tightening the tension spring leads to a bending of the tension spring in such a way that the acute angle mentioned decreases from the unloaded state and is, for example, only 0° -5° in the tightened state. This angle can be reduced to 5-10° in the case of fastening systems with a lower hold-down force. In this tightened state, a torsional moment acts on the torsional section of the tension spring, in particular about an axis that runs normal to the axis of the first leg and forms a tangent to the U-bend.

[0027] The hold-down force acting on the rail foot from the bent end section and the corresponding counterforce acting from the hold-down device on the holding section of the tension spring form a force couple that also forces the torsion section to bend around an axis perpendicular to the axis of the torsional moment, resulting in a corresponding bending around this axis. Due to this bending, the bent end section of the tension spring has a different angle to the support plane at the rail foot in the unloaded state than in the loaded state.So that the bent end section is aligned essentially horizontally in the loaded state in order to ensure a corresponding bearing surface on the rail foot, a preferred embodiment of the invention provides that the bent end section has a bearing surface for bearing on the track body element which, in the unloaded state, runs upwards at an acute angle relative to the central plane or to the flat bearing surface. The angle between the bent end section and the said plane can preferably be 2 ° - 8 °, in particular 5 ° - 7 °. The angle decreases under load due to the said bending moment and is preferably 0 ° - 1 ° in the loaded state.

[0028] When, in the context of the invention, reference is made to an angle between two sections of the tension spring or to a plane in which the sections lie, this refers to the center line of the corresponding sections, i.e. in the case of a circular cross-section, to the center line or axis passing through the center of the circle.

[0029] The tension spring according to the invention is designed to be usable with various types of hold-down devices.

[0030] In a first installation variant, the holding section of the tension spring can be inserted transversely to the longitudinal direction of the rail into a tunnel-shaped recess of the hold-down device towards the rail, so that the hook bend preferably overlaps the rail foot in a final assembly position of the tension spring.

[0031] In a second installation variant, the holding section of the tension spring can be inserted parallel to the longitudinal direction of the rail into a tunnel-shaped recess of the hold-down device, so that the second leg preferably overlaps the rail foot.

[0032] From a constructive point of view, the first and second

[0033] The installation variant can preferably be implemented in that a gap is arranged between the bent end section and the free end region of the holding section in a longitudinal extension of the free end region and in a plan view, i.e. in a normal projection onto the central plane or the flat support surface, on the side of the free end region facing the second leg.

[0034] In a further installation variant, a free space can be provided between the first leg and the free end region of the holding section, through which space a screw shaft of a fastening screw forming the hold-down device can pass and in which space the fastening screw can be moved in the longitudinal direction of the first leg, wherein the screw shaft of the fastening screw has a diameter which is greater than the diameter of a wire forming the tension spring in the holding section, and wherein preferably the inner radius of the hook bend is greater than or equal to the radius of the screw shaft. The said displaceability makes it possible to move the tension spring, when held down by the fastening screw, from a pre-assembly position to a final assembly position and back. If the inner radius of the hook bend is greater than or equal to the radius of the screw shaft, a maximum displacement path is provided.

[0035] Overall, the invention provides a compact, flat, and flexibly usable tension spring, which can also be manufactured cost-effectively due to the low material requirements. Preferably, the tension spring, in a plan view, in particular in a normal projection onto the center plane or the flat support surface, lies within a minimal surrounding rectangle having an aspect ratio of 1:1.5-1:1, preferably 1:1.1-1:1.

[0036] According to a further preferred embodiment, the diameter of the wire forming the tension spring is at least 1 / 7, preferably at least 1 / 6, of the shorter side of a rectangle minimally surrounding the tension spring in a plan view.

[0037] In particular, the bent end section lies within a square corner region of a rectangle minimally surrounding the tension spring in a plan view, which is at most 1 / 9 of the area of ​​the surrounding rectangle.

[0038] According to a second aspect, the invention relates to a rail fastening comprising a tension spring according to the first aspect of the invention and a hold-down device which can be fastened to a base, in particular a sleeper, ribbed plate or angle guide plate, adjacent to a rail, on which hold-down device the holding section is supported in the mounted state of the tension spring in such a way that the bent end section can be arranged to resiliently hold down a track body element, in particular a rail foot of the rail.

[0039] It is preferably provided that the hold-down device, when the tension spring is mounted, not only engages over the free end area of ​​the holding section, but also at least partially over the first leg.

[0040] As already explained in connection with the first aspect of the invention, the tension spring can be tensioned down without a screw or with the aid of a screw. To implement the screwless alternative, a preferred embodiment provides that the hold-down device has or forms a tunnel-shaped recess into which the holding portion of the tension spring can be at least partially inserted.

[0041] Depending on whether the tension spring is to be installed transversely to the longitudinal direction of the rail or in the longitudinal direction of the rail, the holding section of the tension spring can be inserted transversely to the longitudinal direction of the rail into the tunnel-shaped recess towards the rail or inserted parallel to the longitudinal direction of the rail.

[0042] In a design with a tension spring that can be inserted transversely to the longitudinal direction of the rail, the tunnel-shaped recess is preferably open on the side facing the track body element, in particular the rail base, and the hook bend projects out of the tunnel-shaped recess in the finally assembled state of the tension spring and engages over the track body element, in particular the rail base. In this way, the hook bend forms an overload protection device in its state projecting over the track body element. For this purpose, the hook bend is arranged such that there is a vertical distance between the track body element to be held down, in particular the rail base, and the hook bend of the tension spring. Upward movements of the track body element that lie within the vertical distance are resiliently absorbed by the bent end section of the tension spring.However, should an excessive upward movement occur, the track element to be held down will strike the hook bend and will thus be prevented from rising further without overloading the tension spring within its permissible spring travel.

[0043] In the variant with a tension spring that can be inserted transversely to the longitudinal direction of the rail, a pre-assembly position of the tension spring can be achieved in a simple manner by initially only pushing the tension spring in far enough so that it is securely accommodated in the tunnel-shaped recess, but that the hook bend does not yet protrude from the tunnel-shaped recess on the side facing the track element to be held down and the bent end section does not yet come to rest on the track element. Only when the final assembly position is assumed is the tension spring driven further towards the track element until the bent end section presses onto the track element from above.

[0044] Both in the variant with a tension spring that can be inserted transversely to the longitudinal direction of the rail and in the variant with a tension spring that can be inserted in the longitudinal direction of the rail, it can preferably be provided that the hold-down device has a ramp that rises in the insertion direction and on which the bent end section slides during insertion. This results in the bent end section being increasingly pre-tensioned during insertion.

[0045] Particularly preferably, the ramp comprises a first rising ramp section and a second rising ramp section, and an intermediate section located therebetween, on which the bent end section rests in a pre-assembly position of the tension spring. The intermediate section can, for example, have a recess in which the bent end section of the tension spring can engage in order to remain in the pre-assembly position.

[0046] In this context, a preferred further development provides that a step is formed at the end of the ramp, via which the bent end section reaches the final assembly position, in which the end section rests on the track body element, in particular the rail foot, wherein the step forms a rear stop which secures the end section against leaving the final assembly position.

[0047] In the variant with a tension spring that can be inserted longitudinally along the rail, overload protection can be achieved by providing the hold-down device with a stop that overlaps the bent end section at a distance when the tension spring is mounted. Such a stop has the effect of limiting the upward movement of the bent end section.

[0048] The fastening system according to the invention can also be used in the region of a switch for fixing stock rails, wherein the hold-down device can be combined or connected to a sliding chair on the side of the stock rail facing the tongue rail, preferably in such a way that the hold-down device forms at least part of the sliding surface for the tongue rail. In this context, a preferred embodiment provides that the fastening system has a sliding chair assigned to the stock rail and having a sliding surface for a tongue rail, wherein the hold-down device has a further sliding surface that is preferably flush with the sliding surface. Alternatively, the upper surface of the hold-down device can also be arranged lower than the sliding surface of the sliding chair.

[0049] Preferably, the further sliding surface, like the sliding chair itself, is extended in the direction of the stock rail in such a way that the further sliding surface overlaps the rail foot of the stock rail at a distance.

[0050] Preferably, the hold-down device assigned to the sliding chair and the hold-down device arranged on the opposite side of the stock rail can be formed in one piece with a sliding chair plate.

[0051] As already mentioned, one advantage of the tension spring according to the invention is its universal applicability. For example, as already mentioned, the tension spring can be fastened not only without screws, but also with a sleeper screw. In this context, the fastening system according to the invention is preferably designed such that the hold-down device is formed by a fastening screw that can be screwed into the base, in particular a sleeper or plate, or by a hook screw with a nut that is hooked into the base, in particular a ribbed plate, the screw shaft and / or thread of which penetrates a free space between the first leg and the free end region of the holding section of the tension spring in order to hold the tension spring down in the region of the holding section and optionally the first leg.

[0052] With this type of fastening, a pre-assembly position is also easily possible. This can be done by first screwing the tension spring down into the pre-assembly position. The rail is then inserted, whereupon the tension spring, screwed down, is moved into the final assembly position. For this purpose, it is no longer necessary to loosen the screw after inserting the rail and then tighten it to the final tightening torque after pushing the tension spring into the final assembly position, because the tension spring can be easily moved from the pre-assembly position to the final assembly position using a hand or power tool, even when the screw is tightened to the final tightening torque in the pre-assembly position.

[0053] To ensure that the tension spring remains displaceable between the pre-assembly and final assembly positions when screwed down, a preferred embodiment of the invention provides for a stop to be arranged on the base and / or on the hold-down device, which stops the screw-in depth of the hold-down device and preferably interacts with the screw head or the nut of the fastening screw, so that a hold-down force on the tension spring can be limited. The stop thus serves to define the screwed-down state of the tension spring or the tightened state of the screw in such a way that the tension spring remains displaceable between the pre-assembly and final assembly positions.Preferably, the stop defines a minimum vertical distance between the hold-down device and the base, which is equal to or greater than the unloaded diameter of the wire forming the tension spring in the region of the hold-down device, wherein the vertical distance is preferably not more than 1.2 times the wire diameter.

[0054] A deviation of the final tightening torque or the

[0055] Once the screw is tightened against the stop, the clamping force reached at the final tightening torque no longer has a negative effect on the desired tension state of the tension spring. This eliminates the need to check the clearances between the tension clamp and the rail base in the final assembly position, as is necessary, for example, with some common fastening systems using tension springs.

[0056] The stop can further preferably enable compensation for a predominantly one-sided load on the screw in that the stop of the screw provides at least one support point via which, by means of the screw or nut tightened with the final tightening torque, a force acts on the screw which at least partially compensates for the one-sided load on the screw.

[0057] Various variants are possible for moving the tension spring from the pre-assembly to the final assembly position. In particular, the tension spring, with its bent end section, can be twistable or displaceable transversely to the longitudinal direction of the rail between the pre-assembly and final assembly positions when the hold-down clamp is tightened, i.e., particularly in the tension state defined by the stop described above.

[0058] Preferably, the support is designed in the region of the contact surface over which the tension spring passes during displacement so that when the tension spring is moved on the support from the pre-assembly position to the final assembly position along the displacement path, there is no increase, or only a gradual increase, in the pre-tension of the tension spring, so that when the tension spring is moved, damaging stress, particularly due to shear, is excluded for all components subjected to stress. For this purpose, one possible design of a support on the contact surfaces over which the tension spring passes on the support during displacement is free of grooves and depressions transversely to the direction of displacement of the tension spring.

[0059] To prevent the tension spring from moving automatically or accidentally from the final assembly position to the pre-assembly position, it is preferably provided that the base forms a step sloping in the direction of displacement of the tension spring, from which the bent end section descends onto the rail foot when the tension spring is moved from the pre-assembly position to the final assembly position. The step thus forms a rear stop for the bent end section, preventing it from leaving the final assembly position.

[0060] In the pre-assembly position, the tension spring is advantageously arranged on the base in such a way that the insertion of a rail between pre-assembled tension springs is not hindered. This means that sleepers can be provided with pre-assembled tension springs before the rails are laid, so that after the rails have been laid, the tension springs only need to be moved into the final assembly position using a suitable tool. This is preferably achieved by the base having a lateral contact surface for the rail foot and the hold-down device or fastening screw being arranged in such a way that the tension spring does not protrude beyond the contact surface in the pre-assembly position.

[0061] In particular, the distance between the screw shaft and the lateral contact surface can be equal to or greater than the diameter of the wire forming the tension spring.

[0062] For safety reasons, it should be ensured that the fastening screw does not become unintentionally loose when moving the tension spring from the pre-assembly position to the final assembly position. For this purpose, the fact that the asymmetrical tension spring according to the invention, when tensioned, is tensioned predominantly on one side of the screw toward the screw head or nut, while resting on the base on the other side of the screw, can be utilized.

[0063] If the direction of rotation of the screw thread and the installation position or asymmetry of the tension spring are coordinated, a displacement of the tension spring from the pre-assembly position to the final assembly position results in the screw being subjected to a load in the sense of tightening the screw. In other words, the fastening screw or the nut of the hook screw predominantly holds down the free end area of ​​the holding section of the tension spring and the first leg of the tension spring is supported on the base and the tightening direction of the thread of the fastening screw or the hook screw is designed in such a way that the free end area of ​​the holding section directly or indirectly applies a torque in the tightening direction to the fastening screw or the nut of the hook screw when the tension spring is moved transversely to the longitudinal direction of the rail from the pre-assembly position to the final assembly position.For a fastening system with a tension spring that can be rotated between a pre-assembly position and a final assembly position, it is intended that the rotation from the pre-assembly position to the final assembly position takes place in the tightening direction of rotation of the fastening screw or the nut of the hook screw, so that it is directly or indirectly subjected to a torque in the tightening direction of rotation.

[0064] The invention is explained in more detail below with reference to exemplary embodiments shown schematically in the drawing. In these, Fig. 1 shows a perspective view of a tension spring according to the invention, Fig. 2 shows a plan view of the tension spring according to Fig. 1, Fig. 3 shows a view according to arrow III in Fig. 2, Fig. 4 shows a view according to arrow IV in Fig. 2, Fig. 5 shows a first embodiment of a rail fastening using the tension spring according to Fig. 1, Fig. 6 shows a detailed view of Fig. 5, Fig. 7 shows a second embodiment of a rail fastening using the tension spring according to Fig. 1, Fig. 8 shows a detailed view of Fig. 7, Fig. 9 shows a hold-down device according to Figs. 7 and 8 in a perspective view, Fig. 10 shows a side view of the hold-down device according to Fig. 9, Fig. 11 shows a third embodiment of a rail fastening using the tension spring according to Fig. 1, Fig. 12 shows a modified embodiment of the rail fastening of Fig. 11, Fig.13 shows a fourth embodiment of a rail fastening using the tension spring according to Fig. 1, Fig. 14 shows an embodiment according to Fig. 12 with a modified angle guide plate, Fig. 15 shows a view of the angle guide plate according to Fig. 14, Fig. 16 shows a front view of the angle guide plate according to Fig. 14, Fig. 17 shows an exploded view of the angle guide plate according to Fig. 14, Fig. 19 shows the rail fastening according to Fig. 12 in a final assembly position, Fig. 18 shows the rail fastening according to Fig. 12 in a pre-assembly position, Fig. 21 shows a cross-sectional view of the rail fastening according to Fig. 19, Fig. 20 shows a cross-sectional view of the rail fastening according to Fig. 18, Fig. 22 shows an alternative embodiment of the rail fastening in a pre-assembly position, Fig. 23 shows the rail fastening according to Fig. 22 in a final assembly position, Fig. 24 a cross-sectional view of the rail fastening according to Fig. 22, Fig.Fig. 25 is a cross-sectional view of the rail fastening according to Fig. 23, Fig. 26 is a perspective view of the angle guide plate used in the rail fastening according to Figs. 22-25 and Fig. 27 is a further cross-sectional view of the rail fastening according to Fig. 19.

[0065] Fig. 1 shows the tension spring 1 according to the invention, comprising a U-shaped main section which has a U-bend 2, a first leg 3 arranged on one side of the U-bend 2 and a second leg 4 arranged on the other side of the U-bend 2, wherein a hook-shaped holding section 5 which is bent inwards and can be supported on a hold-down device is formed on the first leg 3 and an end section 6 which is bent towards or away from the holding section 5 is formed on the second leg 4. The holding section 5 comprises a free end region 7.

[0066] In Fig. 2 it can be seen that between the bent end section 6 and the free end region 7 of the holding section 5, as seen in a plan view, a gap x is arranged on the side of the free end region 7 facing the second leg 4. The gap allows the insertion of the holding section of the tension spring 1 with the hook bend first into a tunnel-shaped recess of the hold-down device (see Fig. 5-8).

[0067] 3 and 4 that the first leg 3 and the holding section 5 including the free end region 7 lie in the same plane, so that they form a flat support surface a. Since the tension spring 1 is bent from a wire with a circular cross-section, this also means that the center axis of the said sections lie in a common center plane b. In the unloaded state it is further provided that the free end region 7 of the holding section 5 completely covers the U-bend 2 as seen in the direction of a longitudinal extent of the free end region 7 (Fig. 3). In other words, the U-bend, starting from the first leg 3, at least up to the said overlap with the free end region 7, also lies in the same plane as the first leg 3 and the holding section 5 including the free end region 7.

[0068] However, in the further course of the U-bend 2, i.e. in the direction of the second leg 4, the U-bend 2 is bent downwards from the plane a or b, so that the normal distance of the second leg 4 to the plane a or b increases up to the bent end section 6. In Fig. 4 it can be seen that the second leg 4 with its central axis c encloses an acute angle ß with the plane a or b of the holding section 5 and the first leg 3.

[0069] In Fig . 3 it is further shown that the bent end section 6 has a support surface d for resting on the track body element which, in the unloaded state, is slightly inclined upwards in the direction of the arrow III, so that an acute angle a is present between the bent end section 6 or the support surface d and the plane a or b of the holding section 5 and the first leg 3 .

[0070] Fig. 5 shows a rail 8 which is fastened to a sleeper 11 with the interposition of a plate 10 arranged on a base plate 9. The fastening is effected on each side of the rail 8 by means of a tension spring 1 according to Fig. 1, which is inserted into a tunnel-shaped recess 13 of a hold-down device 12. In the final assembly position of the tension spring 1 shown in Fig. 5, the latter presses with its bent end section 6 onto the rail foot 16 of the rail 8, with the optional interposition of an insulator. The hold-down device 12 is fastened to the plate 10 in a suitable manner. For example, the plate 10 and the hold-down device 12 are manufactured in one piece and screwed to the sleeper 11. Alternatively, an anchor can be formed on the underside of the plate 10, which is embedded in the concrete sleeper 11 when it is cast.

[0071] Fig. 6 is an enlarged view of the tension spring 1 inserted into the tunnel-shaped recess 13. It can be seen that the tension spring has been inserted with its holding section 5 in the direction of the arrow 14, i.e. in the longitudinal direction of the rail, into the tunnel-shaped recess 13, so that the bent end section 6 rests on the rail foot 16. When inserted in the direction of the arrow 14, the bent end section 6 slides on a ramp 17 which rises in the insertion direction 14 until it falls over a step formed at the end of the ramp 17 onto the rail foot 16. On the side of the hold-down device 12 facing the rail foot 16, there is also a stop 18 which overlaps the bent end section 6 at a distance and acts together with the end section 6 as an overload protection device.

[0072] 7 and 8 show an alternative design of the rail fastening, in which the tension spring 1 is inserted transversely to the longitudinal direction of the rail, i.e. in the direction of the arrow 14, into the tunnel-shaped recess 13 (see Fig. 9) of the hold-down device 12. When inserted in the direction of the arrow 14, the bent end section 6 slides again along the ramp 17 formed on the outside of the hold-down device 12 until the bent end section 6 falls down onto the rail foot 16 via a step 19 formed at the end of the ramp 17. An insulator 15 can be arranged between the tension spring 1 and the rail foot. In the embodiment shown in Fig.

[0073] In the final assembly position shown in Fig. 8, the holding section 5 emerges from the tunnel-shaped recess 13 on the side facing the rail 8 and forms a stop which overlaps the rail foot 16 with the optional insulator 15 at a distance and which forms an overload protection device.

[0074] The hold-down device 12 used in Fig. 7 and 8 is shown in Fig. .

[0075] 9 and 10 in more detail, wherein it can be seen in particular that the ramp 17 consists of three sections which follow one another in the insertion direction 14. The ramp 17 comprises a first rising ramp section 20 and a second rising ramp section 22 and an intermediate section 21 lying therebetween which has no gradient and on which the bent end section 6 of the tension spring 1 rests in a pre-assembly position. Furthermore, an anchor 31 can be seen in Figs. 9 and 10, with which the hold-down device can be concreted or cast into a concrete sleeper 11 or, for example, a plastic sleeper 11.

[0076] Fig. 11 shows a modified embodiment in which the tension spring 1 is tensioned by a hold-down device in the form of a fastening screw 25. The fastening screw 25 is hooked to the rib 24 as a hook screw or is screwed into the sleeper 11 in such a way that its screw shaft or thread passes through a free space between the first leg 3 and the free end region 7 of the holding section 5 of the tension spring 1. The free space between the first leg 3 and the free end region 7 of the holding section 5 is in this case slot-shaped so that the tension spring 1 can be moved between a pre-assembly position and the final assembly position shown in Fig. 12. In the embodiment shown, the rail base 10 is designed as a ribbed plate whose ribs 24 define the position of the rail foot 16 of the rail 8 on the sleeper 11.

[0077] In the modified embodiment according to Fig. 12, the fastening system comprises on each side of the rail 8 an angle guide plate 26 which engages with a rib formed on the underside in a groove 27 of the sleeper 11.

[0078] Fig. 13 shows the use of a rail fastening according to the invention in the region of a switch, which has a stock rail 8 and a tongue rail 28 that can be moved between a remote and abutting position. The tongue rail 28 slides with its rail foot on a slide chair 29, wherein the hold-down device 12 has a further sliding surface on its upper side that is flush with the sliding surface of the slide chair 29. The hold-down devices 12 arranged on both sides of the stock rail 8 can be formed integrally with a base plate 30.

[0079] The design according to Fig. 14 essentially corresponds to the design according to Fig. 12, but the angled guide plate 26 is constructed in two parts. As can be seen in Figs. 15 and 17, the angled guide plate 26 consists of a first part 32 facing away from the rail and a second part 33 facing the rail. The first part 32 carries a rib 34 which, when installed, engages in the groove 27. The rib 34 preferably has a trapezoidal cross-section and at least one guide surface 38. The first and second parts 32, 33 are displaceable relative to one another along guide surfaces 38, 39 (Fig. 17) which are inclined to the longitudinal direction of the rail, in order to thereby enable adaptation to the respective track gauge. The second part 33 further comprises a plate-shaped support element 41, on which the tension spring 1 rests and which engages over the upper surface of the first element 32. As shown in Fig.17, the plate-shaped support element 41 has at least one oblique guide groove 40 on its underside, into which guide pins or the like (not shown) formed on the upper side of the first element 32 engage in order to hold the two parts 32, 33 together, particularly in the unloaded state. Furthermore, it can be seen that the second part 33, in particular the plate-shaped support element 41, has a through-hole 35 through which the screw 25 passes when the tension spring 1 is in the assembled state. The through-hole 35 is designed as an elongated hole perpendicular to the longitudinal direction of the rail. For the lateral guidance of the tension spring 1, the second part 33, in particular the plate-shaped support element 41, has two walls 37 which run in the insertion direction 14 of the tension spring 1. The elevation 36, which is arranged between the first leg 3 and the free end 7 of the holding section 5 of the tension spring 1, also serves to guide the tension spring 1.

[0080] The tension spring 1 can be moved between the final assembly position shown in Fig. 14 and a pre-assembly position (not shown), in which the tension spring 1 does not overlap the rail foot. The design is such that the screw 25 does not need to be loosened to move the tension spring 1 from the pre-assembly position to the final assembly position.

[0081] The displacement can be carried out, for example, using a lever-like tool.

[0082] Figs. 18 and 19 show, based on the design according to Fig. 12, the displaceability of the tension spring 1 between the pre-assembly position (Fig. 18) and the final assembly position (Fig. 19). Where corresponding components are concerned, reference numerals from Figs. 14-17 have been retained. Figs. 20 and 21 each show a cross-section of Figs. 18 and 19, respectively, along the line XX and XXI, respectively.

[0083] 20 and 21, it can be seen that the fastening screw 25 has a screw head 42 and a screw shaft 43, wherein the screw head 42 compresses the tension spring with the interposition of a washer 44. The elevation 36 of the angled guide plate 26 forms a stop 45, with which the screw head 42 or the washer 44 interacts and which thus limits the screw-in depth of the fastening screw 25. The stop 45 serves to define the compressed state of the tension spring 1 or the tightened state of the fastening screw 25 such that the tension spring 1 remains movable between the pre-assembly and final assembly positions.The stop 45 defines a minimum vertical distance h between the washer 44 and the support surface of the angle guide plate 26, which is equal to or greater than the unloaded diameter of the wire forming the tension spring in this area.

[0084] In Fig. 20 it can be seen that the angle guide plate 26 has a lateral contact surface 46 for the rail foot 16 and the fastening screw 25 is arranged such that the tension spring 1 does not protrude beyond the contact surface 46 in the pre-assembly position.

[0085] Furthermore, Figs. 18 and 19 show a ramp 47 formed on the angle guide plate 26, which is arranged such that the bent end section 6 of the tension spring 1 slides along it during displacement from the pre-assembly position to the final assembly position. The ramp is flat or ascending towards the rail foot 16, with the end of the ramp forming a step sloping towards the rail foot, over which the bent end section 6 descends onto the rail foot 16 during displacement of the tension spring 1 from the pre-assembly position to the final assembly position.

[0086] Figs. 22 and 23 show an alternative embodiment in which the tension spring 1 can be moved from the pre-assembly position (Fig. 22) into the final assembly position (Fig. 23) by rotating it about the screw axis. Figs. 24 and 25 are sectional views of Figs. 22 and 23. For the rotation of the tension spring 1, a rotatable intermediate piece 48 is provided as a stop 45, which is penetrated by the screw shaft 43 and engages between the first leg 3 and the free end region 7 of the tension spring 1 and is pressed there by the fastening screw 25 against the angle guide plate 26, so that the intermediate piece 48 forms a rotatable stop 45, which both limits and transmits the screw-in depth of the fastening screw 25 and its tensioning force to the tension spring 1, which is why the intermediate piece 48 could also be understood as a component of a hold-down device.

[0087] The rotatable stop 45 serves in a similar manner to the previously described movable design to define the screwed-down state of the tension spring 1 or the tightened state of the fastening screw 25 such that the tension spring 1 remains rotatable between the pre-assembly position and the final assembly position. The intermediate piece 48 comprises an area that overlaps the first leg 3 and the free end region 7, whereby the tension spring is tightened when the fastening screw 25 is tightened. The area of ​​the intermediate piece 48 that overlaps the first leg 3 and the free end region 7 defines, as stop 45, a minimum vertical distance h between the bearing surface of the tension spring on the angle guide plate 26 and its opposite contact surface of the intermediate piece

[0088] 48 , which is equal to or greater than the unloaded diameter of the wire forming the tension spring in this area. Furthermore, the intermediate piece 48 comprises an extension

[0089] 49, which engages behind the end face of the free end region 7 of the tension spring 1 or engages in the free space between the free end region 7 and the U-bend 2. The extension 49 acts as a safeguard against horizontal displacement of the tension spring 1 and as a driver to support the transmission of the rotational movement applied by the engagement of a tool on the intermediate piece 48 or stop 45 to the tension spring 1.

[0090] The angled guide plate 26 from Figures 22 to 25 is shown in more detail in Figure 26, and it can be seen that a raised portion 50 is formed on the side 46 facing the rail foot 16. The raised portion 50 has a contoured edge to provide both a first holding surface 53 for the pre-assembly position and a second holding surface 54 for the final assembly position of a rotationally displaceable tension spring 1. Furthermore, the contact surface 46 forms a step 52 extending from the upper edge of the contact surface 46 and descending to a rail foot. So that the hold-down force can be fully transmitted to the rail foot in the final assembly position, the required vertical freedom of movement for a tension spring 1 must be present between the second leg and the angled guide plate 26. For this purpose, a recess 51 ensures that the upper edge of the contact surface 46 is lowered at a corresponding point. level 52 .

[0091] Fig. 27 shows the section SS through the step 52 from Fig. 19.

[0092] This falls to the rail foot by the distance Y.

Claims

Patent claims:

1. Tension spring (1) for holding down a track body element, such as a rail foot of a rail, comprising a U-shaped main section which has a U-bend (2), a first leg (3) arranged on one side of the U-bend (2) and a second leg (4) arranged on the other side of the U-bend (2), wherein a hook-shaped holding section (5) which is bent inwards and can be supported on a hold-down device is formed on the first leg (3) and an end section (6) which is bent towards or away from the holding section (5) is formed on the second leg (4), wherein the U-bend (2) forms a torsion section such that a holding-down force can be applied to the track body element via the bent end section (6).

2. Tension spring according to claim 1, characterized in that the bent end portion (6) extends at an angle of 80-100°, preferably approximately 90°, to the second leg (4).

3. Tension spring according to claim 1 or 2, characterized in that the holding section (5) has a free end region (7) connected to the first leg (3) via a hook bend, which is arranged between the first leg (3) and the second leg (4).

4. Tension spring according to claim 3, characterized in that the first leg (3) and the free end region (7) of the holding section (5) provide a flat support surface in the unloaded state.

5. Tension spring according to claim 3 or 4, characterized in that the first leg (3) and the free end region (7) of the holding section (5) in the unloaded state lie with their respective central axes, preferably over their entire extent, in a central plane which preferably runs parallel to the flat support surface.

6. Tension spring according to claim 3, 4 or 5, characterized in that the hook bend of the holding section (5) has a substantially 180° bend, so that the free end region (7) of the holding section (5), preferably in a normal projection onto the flat support surface or the central plane, runs substantially at least in sections parallel to the first leg (3).

7. Tension spring according to one of claims 3 to 6, characterized in that an imaginary extension of the bent end section (6) overlaps the hook bend in a plan view.

8. Tension spring according to one of claims 5 to 7, characterized in that the first leg (3) and the holding section (5) lie with their respective central axes in the central plane in the unloaded state.

9. Tension spring according to one of claims 4 to 8, characterized in that the bent end section (6) in the unloaded state has a normal distance from the center plane or from the flat support surface.

10. Tension spring according to one of claims 4 to 9, characterized in that the hook bend and the bent end section (6) in the unloaded state have the maximum, normally Define the height of the tension spring (1) measured to the center plane or to the flat support surface.

11. Tension spring according to claim 10, characterized in that the structural height of the tension spring in the unloaded state corresponds to 1.5 to 3 times the diameter of the wire forming the tension spring (1) in the holding section (5).

12. Tension spring according to one of claims 4 to 10, characterized in that the second leg (4) in the unloaded state has a normal distance to the central plane or to the flat support surface.

13. Tension spring according to one of claims 4 to 12, characterized in that the second leg (4) in the unloaded state is inclined at an acute angle relative to the central plane or to the flat support surface.

14. Tension spring according to one of claims 3 to 13, characterized in that the free end region (7) of the holding section (5) covers the U-bend at least partially, preferably completely, when viewed in the direction of a longitudinal extension of the free end region (7).

15. Tension spring according to one of claims 4 to 14, characterized in that the bent end section (6) has a support surface for resting on the track body element, which in the unloaded state extends upwards at an acute angle relative to the central plane or to the flat support surface.

16. Tension spring according to one of claims 3 to 15, characterized in that between the bent end section (6) and the free end region (7) of the holding section (5) in a longitudinal extension of the free end region (7) and, as seen in a plan view, a gap (x) is arranged on the side of the free end region (7) facing the second leg.

17. Tension spring according to one of claims 1 to 16, characterized in that the holding section (5) of the tension spring (1) can be inserted transversely to the longitudinal direction of the rail into a tunnel-shaped recess (13) of the hold-down device towards the rail, so that the hook bend preferably engages over the rail foot (16) in a final assembly position of the tension spring (1).

18. Tension spring according to one of claims 3 to 17, characterized in that a free space is provided between the first leg (3) and the free end region (7) of the holding section (5), which free space can be penetrated by a screw shaft of a fastening screw (25) forming the hold-down device and in which the fastening screw (25) is displaceable in the longitudinal direction of the first leg (3), wherein the screw shaft of the fastening screw (25) has a diameter which is greater than the diameter of a wire forming the tension spring (1) in the holding section (5), and wherein preferably the inner radius of the hook bend is greater than or equal to the radius of the screw shaft.

19. Tension spring according to one of claims 1 to 18, characterized in that the tension spring (1) in a plan view, in particular in a normal projection on the central plane or the flat support surface lies within a minimum surrounding rectangle having an aspect ratio of 1:1.5-1:1, preferably 1:1.1-1:

1.

20. Tension spring according to one of claims 1 to 19, characterized in that the diameter of the wire forming the tension spring (1) is at least 1 / 7, preferably at least 1 / 6, of the shorter side of a rectangle minimally surrounding the tension spring (1) in a plan view.

21. Tension spring according to one of claims 1 to 20, characterized in that the bent end section (6) lies within a square corner region of a rectangle minimally surrounding the tension spring (1) in a plan view, which has at most 1 / 9 of the area of ​​the surrounding rectangle.

22. Rail fastening comprising a tension spring (1) according to one of claims 1 to 21 and a hold-down device (12) which can be fastened on a base, in particular a sleeper (11), ribbed plate or angle guide plate, adjacent to a rail (8), on which the holding section (5) in the mounted state of the tension spring (1) is supported in such a way that the bent end section (6) can be arranged to resiliently hold down a track body element, in particular a rail foot (16) of the rail.

23. Rail fastening according to claim 22, characterized in that the hold-down device, in the mounted state of the tension spring (1), at least partially engages over both a free end region (7) of the holding section (5) and the first leg (3).

24. Rail fastening according to claim 22 or 23, characterized in that the hold-down device (12) has or forms a tunnel-shaped recess (13) into which the holding section (5) of the tension spring (1) can be at least partially inserted.

25. Rail fastening according to claim 24, characterized in that the holding section (5) of the tension spring (1) extends transversely to the longitudinal direction of the rail into the tunnel-shaped Recess (13) can be pushed towards the rail.

26. Rail fastening according to claim 25, characterized in that the tunnel-shaped recess (13) is open on the side facing the track body element, in particular the rail foot (16), and the hook bend protrudes from the tunnel-shaped recess (13) in a final assembly position of the tension spring (1) and engages over the track body element, in particular the rail foot (16).

27. Rail fastening according to claim 24, characterized in that the holding section (5) of the tension spring (1) extends parallel to the longitudinal direction of the rail into the tunnel-shaped recess (13) can be inserted.

28. Rail fastening according to claim 25 or claim 26, characterized in that the hold-down device (8) has a ramp (17) rising in the insertion direction (14), on which ramp the bent end section (6) rests in a sliding manner when the holding section (5) is inserted into the tunnel-shaped recess (13).

29. Rail fastening according to claim 28, characterized in that the ramp (17) has a first rising ramp section (20) and a second rising ramp section (22) and an intermediate section (21) located therebetween, on which the bent end section (6) rests in a pre-assembly position of the tension spring (1).

30. Rail fastening according to claim 28 or 29, characterized in that a step (19) is formed at the end of the ramp (17), via which the bent end section (6) reaches the final assembly position, in which the end section (6) rests on the track body element, in particular the rail foot (16), wherein the step (19) forms a rear stop which secures the bent end section (6) against leaving the final assembly position.

31. Rail fastening according to one of claims 27 to 30, characterized in that the hold-down device (12) has a stop (18) which overlaps the bent end section (6) at a distance in a final assembly position of the tension spring (1).

32. Rail fastening according to one of claims 22 to 31, further comprising a sliding chair (29) assigned to the rail (8) designed as a stock rail, with a sliding surface for a tongue rail (28), wherein a hold-down device (12) is connected to the sliding chair and preferably has a further sliding surface flush with the sliding surface of the sliding chair.

33. Rail fastening according to claim 32, characterized in that the further sliding surface overlaps the rail foot (16) of the stock rail (8) at a distance.

34. Rail fastening according to claim 22 or 23, characterized in that the hold-down device is formed by a fastening screw (25) which can be screwed into the base, in particular a sleeper (11) or plate (10, 26), or by a hook screw with nut which is suspended in a base, in particular a ribbed plate, the screw shaft and / or thread of which forms a free space between the first leg (3) and the free end region (7) of the holding section (5) of the tension spring (1) in order to hold down the tension spring (1) in the region of the holding section (5) and, if applicable, the first leg (3).

35. Rail fastening according to claim 34, characterized in that a stop (45) is arranged on the base and / or on the hold-down device, which limits the screw-in depth of the hold-down device and preferably interacts with the screw head (42) or the nut of the fastening screw (25), so that a hold-down force on the tension spring (1) can be limited.

36. Rail fastening according to claim 35, characterized in that the stop (45) defines a minimum vertical distance between the hold-down device and the base which is equal to or greater than the unloaded diameter of the wire forming the tension spring (1) in the region of the hold-down device, wherein the vertical distance is preferably not more than 1.2 times the wire diameter.

37. Rail fastening according to one of claims 34 to 36, characterized in that the tension spring (1) with its bent end section (6) is displaceable, in particular rotatable or displaceable transversely to the longitudinal direction of the rail, between a pre-assembly position and a final assembly position in the tightened state of the hold-down device.

38. Rail fastening according to claim 37, characterized in that the base forms a step sloping in the direction of displacement (14) of the tension spring (1), from which the bent end section (6) descends onto the rail foot (16) when the tension spring (1) is displaced from the pre-assembly position to the final assembly position.

39. Rail fastening according to claim 38, characterized in that the bent end section (6) lying on the step is arranged higher than the hook bend of the holding section (5).

40. Rail fastening according to one of claims 34 to 39, characterized in that the base has a lateral contact surface for the rail foot and the hold-down device or the fastening screw (25) is arranged such that the tension spring (1) does not protrude beyond the contact surface in the pre-assembly position.

41. Rail fastening according to claim 40, characterized in that the distance between the screw shaft and the lateral contact surface is equal to or greater than the diameter of the wire forming the tension spring (1).

42. Rail fastening according to one of claims 37 to 41, characterized in that the fastening screw or the nut of the hook screw preferably predominantly holds down the free end region (7) of the holding section (5) of the tension spring (1) and the first leg (3) of the tension spring (1) is supported on the base and that the fixed direction of rotation of the thread of the fastening screw or the hook screw is designed such that the free end region (7) of the holding section (5) directly or indirectly applies a torque in the fixed direction of rotation to the fastening screw or the nut of the hook screw when the tension spring (1) is moved transversely to the longitudinal direction of the rail from the pre-assembly position to the final assembly position.

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