Tendon with end connectors

Abstract

A tendon (1, 2) with end connectors at each end of the tendon comprises: a) A first end connector (10, 100) arranged at a first end of the tendon (1, 2) and having a first thimble (10, 110); b) A second end connector (10', 100') arranged at a second end of the tendon and having a second thimble (11', 110'); c) A first load bearing synthetic fiber-based strength member (M1), wound around the first and / or the second thimble and connecting the two end connectors; d) A second load bearing synthetic fiber-based strength member (M2), wound around the first and / or the second thimble and connecting the two end connectors; such that the two end connectors are connected to each other via sections of the strength members located in between the two end connectors.

Description

Technical field

[0001] The invention relates to a tendon with end connectors at each end of the tendon as well as a method for producing such tendons. A further aspect of the invention is related to the use of a tendon for tensioning a structure and / or transmitting tensile forces between structural elements.Background art

[0002] In engineering and construction, a "tendon" usually refers to a high-strength cable or bar that provides tension in a structure and / or transmits tensile forces. Tendons are essential in construction work and modern engineering, enabling the construction of lighter and more efficient structures.

[0003] For example, in post-tensioned concrete construction, tendons are placed within ducts in concrete elements. Once the concrete has cured, the tendons are tensioned and anchored, allowing the concrete to bear higher loads and resist cracking.

[0004] Also, tendons are used in the construction of bridges and high-rise buildings to enhance structural integrity and load distribution. They help manage forces in the structure, improving its stability and durability.

[0005] In tension-based constructions, tendons play a critical role in maintaining shape and stability by holding various components under tension and / or by holding two or more parts of a structure together.

[0006] In order to ensure secure anchoring and efficient load transfer between structural elements, in various construction and engineering applications tendons usually are equipped with so called end connectors. End connectors may be designed differently, depending of the intended purpose.

[0007] US 6,684,585 B2 (Campbell) describes for example an anchorage for a post-tension system including an anchor body having an interior cavity and a generally flat end surface, a tendon extending through the interior cavity of the anchor body, a plurality of wedges in interference-fit relationship between a wall of the interior cavity and a surface of the tendon, a cap member positioned outwardly of the flat end surface, and a ring juxtaposed against the inner surface of the cap member. Thereby, the tendon is made from steel.

[0008] However, tendons made from steel and designed to withstand significant tensile forces require large diameters resulting in an overall heavy weight significantly limiting the application of these tendons.

[0009] Thus, there is still a need to develop improved solutions that do not have the disadvantages mentioned above or have them to a lesser extent.Summary of the invention

[0010] It is the object of the invention to provide improved tendons with end connectors. Especially, the tendons should be as light as possible and at the same time have the highest possible tensile strength and ensure a secure anchoring and efficient load transfer between structural elements.

[0011] The solution of the invention is specified by the features of claim 1. Accordingly, the core of the invention relates to a tendon with end connectors at each end of the tendon, the tendon comprising: a) A first end connector arranged at a first end of the tendon and having a first thimble and a first fixation element for connecting the tendon to a first further element; b) A second end connector arranged at a second end of the tendon and having a second thimble and a second fixation element for connecting the tendon to a second further element; c) A first load bearing synthetic fiber-based strength member, which is connected at its first end to the first end connector or the second end connector, the first strength member extending at least once from the first thimble to the second thimble and at least once from the second thimble to the first thimble, whereby the first strength member at least once is guided around the first thimble and / or the second thimble; and which is connected at its second end to the first or the second end connector; d) A second load bearing synthetic fiber-based strength member, which is connected at its first end to the first end connector or the second end connector, the second strength member extending at least once from the first thimble to the second thimble and at least once from the second thimble to the first thimble, whereby the second strength member at least once is guided around the first thimble and / or the second thimble; and which is connected at its second end to the first or the second end connector; such that the two end connectors are connected to each other via sections of the strength members located in between the two end connectors; whereby the first strength member and the second strength member each comprise a plurality of synthetic fibers.

[0012] The tendon according to the invention turned out to be highly beneficial. When compared with steel-wire based tendons, the weight of the tendons can be reduced significantly thanks to the load bearing synthetic fiber-based strength members while the breaking force can be kept at a high level. Furthermore, tendons according to the invention can be produced with rather small width and / or diameters while still having a high breaking force.

[0013] Thereby, the use of at least two separate synthetic fiber-based strength members that are guided around the thimbles of the end connectors allows for obtaining a highly uniform load distribution between the strength members when the tendon is subjected to a tensile load. This can be achieved in a relatively easy and reliable manner, e.g. by laying the strength members on the thimbles with an essentially constant tensile force.

[0014] Furthermore, the use of thimbles generates a defined and uniform friction force between the thimbles and the strength members when the tendon is subjected to a tensile load. This greatly simplifies production of the tendon, as each section of the strength members running from the first to the second end connector and vice versa does not have to be connected separately to the respective end connector. Nevertheless, a secure and reliable connection is achieved.

[0015] Also, the inventive tendon design is highly flexible since it can easily be embodied with different types of strength members, e.g. having different structures and / or consisting of different fibers materials. Likewise, by adjusting the number of sections of the strength members running from the first to the second end connector and vice versa, the breaking strength can be adapted. This can e.g. be achieved by increasing the number of layers of the strength members on the thimbles with constant width of the tendon and / or by increasing the width of the tendon while keeping the number of layers of the strength members on the thimbles constant.

[0016] In particular, it is possible to produce tendons based on strength members without any metallic components. This in particular results in reduced problems associated with metal or steel based constructions, such as e.g. a reduced risk of corrosion.

[0017] Overall, highly advantageous tendons with end connectors are provided.

[0018] Further aspects and advantageous embodiments of the invention are subject of the further claims and / or outlined throughout the description.

[0019] According to a further preferred embodiment, the tendon comprises at least one further load bearing synthetic fiber-based strength member, whereby each of the at least one further synthetic strength member is connected at its first end to the first end connector or the second end connector, the at least one further strength member extending at least once from the first thimble to the second thimble and at least once from the second thimble to the first thimble, whereby each of the at least one further synthetic strength member at least once is guided around the first thimble and / or the second thimble; and each of the at least one further synthetic strength member is connected at its second end to the first or the second end connector; whereby each of the at least one further strength member comprises a plurality of synthetic fibers that are twisted or untwisted.

[0020] In particular, the tendon comprises in total at least three, at least four, at least five, at least six, at least seven, at least eight, at least nine or at least ten individual strength members. For example, the tendon comprises 2 - 50, in particular 3 - 40 or 4-30, individual strength members.

[0021] Especially, an individual length of the first and the second strength member is essentially identical. Further preferred the individual lengths of all strength members are essentially identical. However, other configurations are possible as well.

[0022] Especially, the first strength member, the second strength member and / or the at least one further strength member is guided at least once, especially at least twice, in particular at least three times, around the first thimble and at least once, especially at least twice, in particular at least three times around the second thimble.

[0023] Especially, the first strength member, the second strength member and / or the at least one further strength member is guided around the first thimble and the second thimble the same number of times.

[0024] According to a special embodiment, the first end of the first strength member and the second end of the first strength member are connected to different end connectors. In another embodiment, the first end of the first strength member and the second end of the first strength member are connected the same end connector.

[0025] Likewise, in particular, the first end of the second strength member and the second end of the second strength member are connected to different end connectors or to the same end connector. Furthermore, in particular, the first end of the at least one further strength member and the second end of the at least one further strength member are connected to different end connectors or to the same end connector.

[0026] The plurality of synthetic fibers of the first strength member, the second strength member and / or the at least one further strength member may be twisted or untwisted.

[0027] Especially, the strength members consist of synthetic fiber cords, synthetic fiber strands and / or a synthetic fiber ropes. The synthetic fiber cords, synthetic fiber strands and / or a synthetic fiber ropes in particular may be wrapped in a film and / or extruded with covering material, especially the film and / or the covering material are made of synthetic material, in particular polymeric material.

[0028] The individual strength members in particular comprise or consist of carbon fibers, aramid fibers, high-density polyethylene fibers, glass fibers, basalt fibers, polyester fibers, and / or LCP fibers. LCP fibers are liquid crystal polymer fibers. Especially, the LCP fibers comprise aromatic rings with ester and / or amide linkages, in particular arranged in a highly ordered, semi-crystalline state.

[0029] Preferably, the individual strength members are based on or consist of fibers with a tensile strength of at least 600 MPa, preferably at least 1'000 MPa, in particular at least 1'800 MPa, more preferred at least 2'500 MPa or at least 3'000 MPa.

[0030] Especially, the sections of the strength members in between the first and the second end connector are aligned in parallel.

[0031] In particular, the sections of the strength members in between the first and the second end connector are arranged such that they together from a body with a circular, elliptical or rectangular cross-section in a direction perpendicular to the longitudinal axis.

[0032] Especially the strength members are not twisted with each other or any other element. However, for special applications this is an option.

[0033] According to a preferred embodiment, a total width of the sections of the strength members in between the first and the second end connector, measured in a direction perpendicular to a longitudinal axis of the tendon is from 30 - 600 mm, especially 40 - 400 mm, in particular 50 - 300 mm. Such kind of tendons can be configured to feature a high breaking force suitable for many heavy-duty applications. However, other widths are possible, if desired.

[0034] In particular, a length of the tendon, especially measured form the first fixation element of the first end connector to the second fixation element of the second end connector is from 0.5 - 750 m, especially, 2 - 500 m, for example 5 - 100 m.

[0035] Especially the two end connectors of the tendon are spatially separated from each other, e.g. a closest distance between the two end connectors is from 0.4 - 750 m, especially 1.5 - 500 m, for example 4.5 - 100 m. Put differently, a length of the sections of the strength members in between the two end connectors preferably is from 0.4 - 750 m, especially 1.5 - 500 m, for example 4.5 - 100 m.

[0036] In particular, in between the first and the second end connector the strength members are kept together by an enveloping layer.

[0037] In particular, the enveloping layer is in direct contact with an outermost layer of the strength members.

[0038] According to a preferred embodiment, the enveloping layer comprises or consists of a wrapping foil. Such an enveloping layer can be produced by simply wrapping a foil of synthetic material around the tendon with one or more turns. A free longitudinal end of the foil then can be connected to the other longitudinal end of the foil and / or an underlying section of the foil.

[0039] Preferably, the enveloping layer comprises or consists of a synthetic material. The synthetic material of the enveloping layer preferably is selected from thermoplastic polyurethane (TPU), thermoplastic elastomers (TPE), and / or polyethylene (PE). However, other materials are possible as well.

[0040] In another preferred embodiment, a total number of sections of the strength members running from the first to the second end connector and sections of the strength members running from the second to the first end connector is from 10 - 2'000, especially 50 - 1'500 or 100 - 1'000.

[0041] Preferably, a wrap angle of the first strength member, the second strength member and / or the at least one further strength member on the first thimble and / or the second thimble, especially in each turn, is within a range of 180 - 300°. This means that the respective strength member(s) are not wrapped several times around the first thimble and / or the second thimble in a single turn.

[0042] Especially, the strength members form a layered structure with 5 - 30, especially 10-20 layers of strength members on each thimble. Thereby, preferably, the first strength member is closest to the first thimble and / or the second thimble in the layered structure and the second strength member and optionally any further strength member is / are placed on the first strength member and / or further spaced apart from the first thimble and / or the second thimble than the first strength member.

[0043] Especially, the first strength member, the second strength member and / or the at least one further strength member has / have a diameter of 1 - 20 mm. especially 2 - 15 mm, in particular 3-10 mm.

[0044] A breaking force or ultimate tensile strength of the individual strength members preferably is from 5 - 500 kN, especially 10 - 250 kN, in particular 20 - 50 kN.

[0045] Especially, the breaking force is meant to be the maximum stress that a material can withstand while being stretched or pulled before breaking.

[0046] In particular, a linear density of the individual strength members is from 5 - 200 g / m, especially 10- 150 g / m, in particular 20 - 80 g / m.

[0047] Especially, a breaking force of the tendon is from 1'000 - 50'000 kN, especially 2'000 - 40'000 kN, in particular 5'000 - 30'000 kN.

[0048] In a preferred embodiment, a linear density of all strength members together in the tendon is from 1 - 50 kg / m, especially 2-40 kg / m, in particular 5-30 kg / m.

[0049] According to a further preferred embodiment, the strength members are essentially identical with respect to their structure and / or with respect to a property selected from tensile strength, length and / or diameter. This allows inter alia for obtaining a highly homogeneous load distribution across the whole cross-section of the tendon. This in turn is beneficial with respect to the breaking force and / or the lifetime of the tendon.

[0050] With respect to the selected property, each individual strength member preferably does not deviate by more than 2%, especially not more than 1%, in particular not more than 0.5%, from an arithmetic average of the property of all individual strength members.

[0051] In a special embodiment, the tendon does not comprise any metallic strength members and / or metallic reinforcement layers, and / or the tendon, apart from the end connectors, is free of metallic elements. This allows for reducing the weight of the tendon and / or to avoid problems associated with metallic elements. Nevertheless, for special applications, metallic components, such as e.g. metallic strength members and / or metallic reinforcement layers, are possible as well.

[0052] Preferably, the strength members are arranged such that a tension of the strength member is essentially identical when the tendon is subjected to a tensile load.

[0053] In particular, the first thimble and / or the second thimble comprises a support surface for the strength members, which at least in parts has the form of a cylinder sector surface, especially the support surface for the strength members at least in parts has the form of a cylinder sector surface and in parts has the form of a wedge shaped surface.

[0054] Preferably, the cylinder sector surface spans an angular range of 180 - 300° around a central geometrical axis of the cylinder sector.

[0055] However, thimbles with other structures, e.g. cylindrical thimbles are possible as well.

[0056] A width of the first and / or the second thimble, measured in a direction perpendicular to a longitudinal axis of the tendon especially is from 30 - 600 mm, especially 40 - 400 mm, in particular 50 - 300 mm.

[0057] According a further preferred embodiment, the first end connector and / or the second end connector comprise(s) a guide bushing for the strength members, whereby the guide bushing is located at an end of the end connector(s) facing the other end connector, especially at a face end of prongs and / or plane-planar plate-shaped elements, and the guide bushing surrounds the strength members and holds them positively in position in a direction perpendicular to the longitudinal axis of the tendon.

[0058] Especially, the guide bushing has a cylindrical, elliptical or rectangular opening for receiving the strength members.

[0059] Further preferred, the guide bushing comprises or consists of two symmetrical halves that are mechanically attachable, e.g. with screws, to the tendon, especially after the strength members have been arranged and connected with the end connectors.

[0060] According to a further preferred embodiment, the first and / or the second end connector each comprise one or more eyelets, e.g. through holes in the end connectors, in which the first and / or second ends of the strength members are received and fixed, e.g. adhesively fixed, fixed in a form-fit manner and / or fixed in a force-fit manner. This allows for a reliable and defined fixation of the ends of the strength member at the end connectors.

[0061] The first end connector and / or the second end connector in a special embodiment are configured as a fork connector, especially featuring two or more, preferably two, parallel prongs with a gap between them, the prongs preferably having a through hole, allowing the end connector to interface with a mating component, such as e.g. a clevis pin, bolt and / or hinge. Preferably, the through holes of the prongs are arranged coaxially.

[0062] In a fork connector, the prongs may be configured as plane-planar plate-shaped elements.

[0063] Especially, the first end connector comprises two plane-planar plate-shaped elements which are connected by the first thimble and extend from it in a direction opposite to the second end connector, and optionally also in a direction towards the second end connector; and / or the second end connector comprises two plane-planar plate-shaped elements which are connected by the second thimble and extend from it in a direction opposite to the first end connector, and optionally also in a direction towards the first end connector.

[0064] The plane-planar plate-shaped elements of the first end connector, especially in a section opposite to the second end connector, each comprise a through hole forming the first fixation element for connecting the tendon to a first further element; and / or the plane-planar plate-shaped elements of the second end connector, especially in a section opposite to the first end connector, each comprise a through hole forming the second fixation element for connecting the tendon to a second further element.

[0065] Thereby, in particular, the plane-planar plate-shaped elements of the first end connector, especially in a section adjacent the first thimble, each comprise at least one, preferably two of the eyelets and / or the plane-planar plate-shaped elements of the second end connector, especially in a section adjacent the second thimble, each comprise at least one, preferably two, of the eyelets.

[0066] Especially, each of the prongs and / or plane-planar plate-shaped elements comprises at least one eyelet, especially a plurality of eyelets, on opposing sides of the thimble, especially in a section of the prongs and / or plane-planar plate-shaped elements protruding laterally beyond the thimble.

[0067] The prongs and / or the plane-planar plate-shaped elements preferably protrude laterally beyond the thimble of the end connector, especially for securing the strength members in a direction perpendicular to the longitudinal axis of the tendon.

[0068] Especially, the end connectors are made of steel, titanium, alloy, synthetic material and / or a composite material. However, other materials may be suitable as well.

[0069] A further aspect of the present invention is related to a method for producing a tendon with end connectors at each end of the tendon, especially a tendon as described above, comprising the steps of: (i) Providing a first end connector to be arranged at a first end of the tendon and having a first thimble and a first fixation element for connecting the tendon to a first further element; (ii) Providing a second end connector to be arranged at a second end of the tendon and having a second thimble and a second fixation element for connecting the tendon to a second further element; (iii) Connecting a first load bearing synthetic fiber-based strength member of finite length with its first end to the first end connector or to the second end connector, guiding the first strength member at least once from the first thimble to the second thimble and at least once from the second thimble to the first thimble, whereby the first strength member at least once is guided around the first thimble and / or the second thimble; and connecting the strength member at its second end to the first or the second end connector; (iv) Connecting a second load bearing synthetic fiber-based strength member of finite length with its first end to the first end connector or the second end connector, guiding the second strength member at least once from the first thimble to the second thimble and at least once from the second thimble to the first thimble, whereby the second strength member at least once is guided around the first thimble and / or the second thimble; and connecting the strength member at its second end to the first or the second end connector; such that the two end connectors are connected to each other via sections of the strength members located in between the two end connectors; whereby the first strength member and the second each comprise a plurality of synthetic fibers.

[0070] In particular, the inventive method is performed such that one or more of the above described optional features of the tendons are obtained as well.

[0071] Especially, the first and / or second ends of the strength members are received and fixed in eyelets of the first and / or the second end connector, e.g. adhesively fixed, fixed in a form-fit manner and / or fixed in a force-fit manner.

[0072] In particular, the strength members are laid around the thimbles with an essentially constant tensile force. This allows for obtaining a highly uniform load distribution between the strength members when the tendon is subjected to a tensile load.

[0073] Further preferred, the method comprises a step of mounting a guide bushing for the strength members on the first end connector and / or the second end connector, whereby the guide bushing preferably is mounted at an end of the end connector(s) facing the other end connector and the guide bushing surrounds the strength members and holds them positively in position in a direction perpendicular to the longitudinal axis of the tendon.

[0074] Especially, the guide bushing comprises or consists of two symmetrical halves that are attached to the tendon after the strength members have been arranged and connected with the end connectors.

[0075] According to a further preferred implementation of the method, sections of the strength members in between the first and the second end connector are enveloped with an enveloping layer keeping together the strength members.

[0076] Another aspect of the present invention is directed to the use of a tendon as described above for tensioning a structure and / or transmitting tensile forces between structural elements, e.g. in post-tensioned concrete constructions, infrastructure constructions and / or buildings.

[0077] Other advantageous embodiments and combinations of features result from the detailed description below and the entirety of the claims.Brief description of drawings

[0078] The drawings used to explain the embodiments show: Fig. 1a perspective view of an end connector for a tendon; Fig. 2a top view of the end connector of Fig. 1; Fig. 3a schematic view of a cross-section along a longitudinal axis of a tendon comprising a first end connector and a second end connector after a first strength member has been connected to the two end connectors; Fig. 4a schematic view of the cross-section along a longitudinal axis of the tendon of Fig. 3 after a second strength member has been connected to the two end connectors; Fig. 5a schematic view of the first connector of Fig. 4 from the left side along a longitudinal axis; Fig. 6a cross-section along line A-A of Fig. 4 in a configuration where the strength members are longer and thus guided further times around the first and the second thimble before fixing the ends in the respective eyelets; and whereby the sections of the strength members in between the first and the second end connector are surrounded and kept together by an enveloping layer; Fig. 7a second tendon comprising a first end connector and second end connector with three strength members extending between the two end connectors; Fig. 8a schematic view of a cross-section of the right side of the tendon of Fig. 7 along a longitudinal axis; Fig. 9an arrangement in which a tendon is used to connect a first structural element with a second structural element.

[0079] In the figures, the same components are given the same reference symbols.Exemplary embodiments

[0080] Fig.1 shows a perspective view of an end connector 10 for a tendon while Fig. 2 shows a top view of the end connector 10 of Fig. 1.

[0081] The end connector 10 is configured as a fork connector having two parallel prongs in the form of two plane-planar plate-shaped elements 12a, 12b with a gap 13 between them. Each of the elements 12a, 12b has a through hole 15a, 15b as a fixation element allowing the end connector 10 to interface with a mating component of a further element. The two elements 12a, 12b are connected by a thimble 11 with a first part 11.1 having a cylinder sector surface and a second part 11.2 having a wedge shaped surface tapering towards the end of the end connector 10 opposite the through holes 15a, 15b. The cylinder sector surface spans an angular range of about 190°. The elements 12a, 12b elements protrude laterally beyond the thimble 11.

[0082] Additionally, the end connector 10 comprises a guide bushing 16 with a cylindrical opening for guiding strength members. The guide bushing 16 is located at the end of the end connector 10 opposite the through holes 15a, 15b.The guide bushing 16 consists of two symmetrical halves that are mechanically attachable to the elements 12a, 12b, with screws.

[0083] The plane-planar plate-shaped elements 12a, 12b in sections adjacent the thimble 11 each comprise several eyelets 14a, 14b. Each element 12a, 12b comprises a first set of eyelets at a first longitudinal edge and a second set of eyelets at a second longitudinal edge of the element 12a, 12b.

[0084] Fig. 3 shows a schematic view of a cross-section along a longitudinal axis of a tendon 1 comprising a first end connector 10 (left side) and a second end connector 10' (right side) after a first strength member M1 has been connected to the two end connectors 10, 10'.

[0085] The end connectors 10, 10' are identical in design with the end connector of Fig. 1. Elements of the second end connector 10' that are identical with the elements of the first connector 10 have the same reference number followed by an additional apostrophe ('),

[0086] The strength member M1 for example is a strand with a diameter of 6 mm based on a plurality of aramid fibers. It is connected at its first end M1.1 to one of the lower eyelets 14b of the first end connector 10, is guided around the first thimble 11, extends from the first thimble 11 to the second thimble 11' of the second end connector 10', is guided around the second thimble 11', extends from the second thimble 11' to the first thimble 11 and is connected at its second end M1.2 to one of the upper eyelets 14b of the first end connector 10.

[0087] In the region S between the first end connector 10 and the second end connector 10', the sections of the strength member M1 run in parallel.

[0088] Fig. 4 shows a schematic view of the cross-section along a longitudinal axis of the tendon 1 shown in Fig. 3 after a second strength member M2 has been connected to the two end connectors 10, 10'.

[0089] The strength member M2 for example is identical in design with the first strength member M1. The second strength member M2 It is connected at its first end M2.1 to one of the lower eyelets 14b' of the second end connector 10', is guided around the second thimble 11', extends from the second thimble 11' to the first thimble 11 of the first end connector 10, is guided around the first thimble 11, extends from the first thimble 11 to the second thimble 11' and is connected at its second end M2.2 to one of the upper eyelets 14b' of the second end connector 10'.

[0090] In the region S between the first end connector 10 and the second end connector 10', all of the four sections of the strength members M1, M2 run in parallel.

[0091] In practice, the strength members M1, M2 can be longer and thus guided further times around the first 11 and the second thimbles 11' before fixing the ends M1.2, M2.2 in the respective eyelets 14b, 14b'. In this manner, a total number of sections of the strength members M1, M2 running from the first 10 to the second end connector 10' and sections of the strength members running from the second to the first end connector can for example be in the range of 10 - 1'000.

[0092] Fig. 5 shows a schematic view of the first connector 10 of Fig. 4 from the left side along a longitudinal axis. The strength members M1, M2 are uniformly distributed over the thimble 11.

[0093] Fig. 6 shows a cross-section along line A-A of Fig. 4 in a configuration where the strength members M1, M2 are longer and thus guided further times around the first 11 and the second thimble 11' before fixing the ends M1.2, M2.2 in the respective eyelets 14b, 14b'; and whereby the sections of the strength members M1, M2 in between the first 10 and the second end connector 10' are surrounded and kept together by an enveloping layer 20, e.g. made of synthetic material.

[0094] The sections of the strength members M1, M2 in region S in between the first 10 and the second 10' end connector are arranged such that they together from a body with a circular cross-section in a direction perpendicular to the longitudinal axis of the tendon.

[0095] Fig. 7 shows a second tendon 2 comprising a first end connector 100 and second end connector 100'. Fig. 8 shows a schematic view of a cross-section of the right side of the tendon 2 along a longitudinal axis.

[0096] The first end connector 100 is configured as a fork connector having two parallel plane-planar plate-shaped elements 120a, 120b. Each of the elements 120a, 120b has eyelets 140a, 140b and a through hole 150a, 150b as a fixation element allowing the end connector 100 to interface with a mating component of a further element. The two elements 120a, 120b are connected by a thimble 110 with a first part 110.1 having a cylinder sector surface and a second part 110.2 having a wedge shaped surface tapering towards the end of the end connector 10 opposite the through holes 150a, 150b. The second end connector 100' is identical in design.

[0097] The tendon 2 comprises for example three strength members M1, M2, M3, which extend between the two end connectors 100, 100' and which are wound around the thimbles several times, i.e. similar to the strength members of tendon 1. In contrast to tendon 1, the strength members M1, M2, M3 in region S between the first 100 and the second 100' end connector are arranged such that they together from a body with a rectangular cross-section in a direction perpendicular to the longitudinal axis of the tendon.

[0098] Fig. 9 shows an arrangement in which tendon 1 is used to connect a first structural element SE1 with a second structural element SE2. Thereby, the end connectors 10, 10' are fixed on the structural elements SE1, SE2 with pins P1, P2, which are arranged in the through holes 15, 15a and matching holes of the structural elements SE1, SE2.

[0099] The exemplary embodiments are not to be understood as restrictive and can be modified within the scope of the invention.

Claims

1. A tendon (1, 2) with end connectors at each end of the tendon, the tendon comprising: a) A first end connector (10, 100) arranged at a first end of the tendon (1, 2) and having a first thimble (10, 110) and a first fixation element (15a, 150a) for connecting the tendon (1, 2) to a first further element (SE1); b) A second end connector (10', 100')arranged at a second end of the tendon and having a second thimble (11', 110') and a second fixation element (15a', 150a') for connecting the tendon (1, 2) to a second further element (SE2); c) A first load bearing synthetic fiber-based strength member (M1) of finite length, which is connected at its first end (M1.1) to the first end connector (10, 100) or the second end connector (10', 100'), the first strength member (M1) extending at least once from the first thimble (11, 110) to the second thimble (11', 110') and at least once from the second thimble (11', 110') to the first thimble (11, 110), whereby the first strength member (M1) at least once is guided around the first thimble (11, 110) and / or the second thimble (11', 110'); and which is connected at its second end (M1.2) to the first (10) or the second end connector (10'); d) A second load bearing synthetic fiber-based strength member (M2) of finite length, which is connected at its first end (M2.1) to the first end connector (10, 100) or the second end connector (10', 100'), the second strength member (M2) extending at least once from the first thimble (10, 100) to the second thimble (10', 100') and at least once from the second thimble (10', 100') to the first thimble (10, 100), whereby the second strength member (M2) at least once is guided around the first thimble (11, 110) and / or the second thimble (11', 110'); and which is connected at its second end (M2.2) to the first (10) or the second end connector (10'); such that the two end connectors are connected to each other via sections of the strength members located in between the two end connectors; and whereby the first strength member (M1) and the second strength member (M2) each comprise a plurality of synthetic fibers.

2. Tendon according to claim 1, comprising at least one further load bearing synthetic fiber-based strength member (M3), whereby each of the at least one further synthetic strength member (M3) is connected at its first end to the first end connector (10, 100) or the second end connector (10', 100'), the at least one further strength member (M3) extending at least once from the first thimble to the second thimble and at least once from the second thimble to the first thimble, whereby each of the at least one further synthetic strength member (M3) at least once is guided around the first thimble and / or the second thimble; and each of the at least one further synthetic strength member (M3) is connected at its second end to the first (10, 100) or the second end connector (10', 100'); whereby each of the at least one further strength member (M3) comprises a plurality of synthetic fibers.

3. Tendon according to any of preceding claims, whereby the strength members (M1, M2, M3) consist of synthetic fiber cords, synthetic fiber strands and / or a synthetic fiber ropes, which, in particular, are wrapped in a film and / or extruded with covering material.

4. Tendon according to any of preceding claims, whereby the sections of the strength members (M1, M2, M3) in between the first (10, 100) and the second end connector (10', 100') are aligned in parallel.

5. Tendon according to any of preceding claims whereby a total width of all sections of the strength members (M1, M2, M3) in between the first (10, 100) and the second end connector (10', 100'), measured in a direction perpendicular to a longitudinal axis of the tendon is from 30 - 600 mm, especially 40 - 400 mm, in particular 50 - 300 mm.

6. Tendon according to any of preceding claims whereby the sections of the strength members (M1, M2, M3) in between the first (10, 100) and the second end connector (10', 100') are kept together by an enveloping layer (20, 200).

7. Tendon according to any of preceding claims, whereby a total number of sections of the strength members (M1, M2, M3) running from the first (10, 100) to the second end connector (10', 100') and section of the strength members (M 1. M2, M3) running from the second (10', 100') to the first end connector (10, 100) is from 10 -2'000, especially 50 - 1'500 or 100 - 1'000.

8. Tendon according to any of preceding claims, whereby a wrap angle of the first strength member (M1), the second strength member (M2) and / or the at least one further strength member (M3) on the first thimble (11, 110) and / or the second thimble (11', 110') is within a range of 180 - 270°.

9. Tendon according to any of preceding claims, whereby the first strength member (M1), the second strength member (M2) and / or the at least one further strength member (M3) has / have a diameter of 1 - 20 mm, especially 2-15 mm, in particular 3-10 mm.

10. Tendon according to any of preceding claims, whereby the first thimble (11, 110) and / or the second thimble (11', 110') comprises a support surface (11.1, 11.2) for the strength members (M1, M2, M3), which at least in parts has the form of a cylinder sector surface, especially the support surface for the strength members at least in parts has the form of a cylinder sector surface and in parts has the form of a wedge shaped surface.

11. Tendon according to any of preceding claims , whereby the first end connector (10, 100) and / or the second end connector (10', 100') comprise(s) a guide bushing (16, 16') for the strength members (M1, M2, M3), whereby the guide bushing (16, 16') is located at an end of the end connectors facing the other end connector and the guide bushing (16, 16') surrounds the strength members (M1, M2, M3) and holds them positively in position in a direction perpendicular to the longitudinal axis of the tendon.

12. Tendon according to any of preceding claims, whereby the guide bushing (16, 16a) comprises or consist of two symmetrical halves that are mechanically attachable to the tendon after the strength members (M1. M2, M3) have been arranged and connected with the end connectors (10, 100, 10', 100').

13. Tendon according to any of preceding claims, whereby the first (10, 100) and / or the second end connector (10', 100') each comprise one or more eyelets (14a, 14b, 14a', 14b'), e.g. through holes in the end connectors, in which the first (M1.1, M2.1) and / or second ends (M2.1, M2.2) of the strength members (M1, M2) are received and fixed, e.g. adhesively fixed, fixed in a form-fit manner and / or fixed in a force-fit manner.

14. Tendon according to any of preceding claims, whereby the first end connector (10, 100) and / or the second end connector (10', 100') are configured as a fork connector especially featuring two or more, preferably two, parallel prongs (12a, 12b, 12a', 12b') with a gap (13) between them, the prongs (12a, 12b, 12a', 12b') preferably having a through hole (15a, 15b, 15a', 15b', allowing the end connector to interface with a mating component, such as e.g. a clevis pin, bolt and / or hinge.

15. Method for producing a tendon (1, 2) with end connectors at each end of the tendon, especially a tendon according to any of preceding claims comprising the steps of: (i) Providing a first end connector (10, 100) to be arranged at a first end of the tendon and having a first thimble (11, 110) and a first fixation element (15a, 15b) for connecting the tendon to a first further element (SE1); (ii) Providing a second end connector (10', 100') to be arranged at a second end of the tendon and having a second thimble (11', 110') and a second fixation element (15a', 15b') for connecting the tendon to a second further element (SE2); (iii) Connecting a first load bearing synthetic fiber-based strength member (M1) of finite length with its first end (M1.1) to the first end connector (10, 100) or to the second end connector (10', 100'), guiding the first strength member (M1) at least once from the first thimble (11, 110) to the second thimble (11', 110') and at least once from the second thimble (11', 110') to the first thimble (11, 110), whereby the first strength member (M1) at least once is guided around the first thimble (11, 110) and / or the second thimble (M11', 110'; and connecting the first strength member (M1) at its second end (M1.2) to the first or the second end connector; (iv) Connecting a second load bearing synthetic fiber-based strength member (M2) of finite length with its first end (M2.1) to the first end connector (10, 100) or the second end connector (10', 100'), guiding the second strength member (M2) at least once from the first thimble (11, 110) to the second thimble (11', 110') and at least once from the second thimble (11', 110') to the first thimble (11, 110), whereby the second strength member (M2) at least once is guided around the first thimble (11, 110) and / or the second thimble (11', 110'; and connecting the second strength member (M2) at its second end (M2.2) to the first or the second end connector; such that the two end connectors are connected to each other via sections of the strength members located in between the two end connectors; whereby the first strength member (M1) and the second (M2) each comprise a plurality of synthetic fibers.

16. Use of a tendon (1, 2) according to any of claims 1 - 14 for tensioning a structure and / or transmitting tensile forces between structural elements (SE1, SE2), e.g. in post-tensioned concrete constructions, infrastructure constructions and / or buildings.

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