Transport anchors for concrete components, especially for double wall elements made of concrete

Abstract

Transport anchors for concrete components, especially for double wall elements made of concrete, including - a load-bearing bracket (2) with two anchoring legs (7) arranged side by side at a lateral distance, which merge into each other to form a U-shaped or V-shaped anchor head (5), and - a compression rod (10, 10') with end compression rod heads (12, 12'), wherein the compression rod (10, 10') extends transversely to the anchoring legs (7), is arranged between them and is connected to the anchoring legs (7) with its compression rod heads (12, 12') in a force-transmitting manner, characterized in that the compression rod (10, 10') is made of a metallic material and is manufactured by forming.

Description

field of technology

[0001] The invention relates to a transport anchor for concrete components, in particular for double wall elements made of concrete, comprising a load bracket with two anchoring legs arranged side by side at a lateral distance, which merge into one another to form a U-shaped or V-shaped anchor head, and a compression rod with end compression rod heads, wherein the compression rod runs transversely to the anchoring legs, is arranged between them and is connected to the anchoring legs with its compression rod heads in a force-transmitting manner. State of the art

[0002] Transport anchors of the described type are primarily used for erecting, transporting, and positioning double-wall elements made of concrete. Such double-wall elements typically consist of two wall shells held parallel to each other by reinforcement at a clear distance. After they have been positioned on the construction site, the space between the wall shells is filled with cast-in-place concrete to complete the building wall.

[0003] When handling the double-wall elements in the precast plant, during transport, and on the construction site, a crane is typically used as a lifting device. Its lifting slings are attached to the U- or V-shaped anchor head of a transport anchor. To transfer the lifting force, the transport anchors' anchoring legs are embedded in the concrete of the wall panels, while the anchor head remains free and serves as the lifting point. To prevent the anchoring legs from breaking out of the concrete panels due to the axial, inclined, and transverse tensile loads that occur during erection and lifting, the two anchoring legs are held apart at the transition to the anchor head by a compression bar.

[0004] From DE 20 2012 001 342 U1, a transport anchor for double concrete walls is known, consisting of two parallel legs and a stirrup connecting the legs. A compression bar is provided in the transition area between the legs and the stirrup, which, under load, supports the two legs against each other and maintains a distance between them. The compression bar is connected to the legs by a weld. A disadvantage of this design is that the transport anchor experiences a certain degree of embrittlement in the area of ​​the weld, which, due to the resulting uneven load distribution along the length of the legs, impairs the load-bearing capacity of the transport anchor.

[0005] FR 3 112 566 A1 discloses a transport anchor for double walls, the two legs of which are held apart by a crossbar. To attach the crossbar to the legs, the ends of the crossbar are provided with through holes through which the crossbar can be slipped onto the legs. Elastic clamping wedges are attached to the legs below the crossbar to fix it in position. Unlike welded connections, this type of connection between the crossbar and the legs preserves the load-bearing capacity of the transport anchor. However, slipping the crossbar onto the legs and attaching the elastic clamping wedges is very material- and labor-intensive.

[0006] Another way to avoid a welded connection between the leg and the compression member is described in DE 10 2011 055 142 A1. An elastic force transmission element is provided at each end of the compression member shown therein. The force transmission elements are supported by the legs and the inner surface of the concrete shells of the double wall without forming a rigid connection with the legs. The elastic force transmission elements are intended to prevent temperature- or load-induced deformations from causing damage to the double wall. However, the elastic force transmission elements represent areas of lower strength, which limits the load-bearing capacity of the transport anchor. Description of the invention

[0007] Against this background, the object of the present invention is to provide a transport anchor for concrete components and in particular for double wall elements, which is characterized by high load-bearing capacity and safety as well as simple handling and high cost-effectiveness.

[0008] This problem is solved by a transport anchor having the features of claim 1.

[0009] Advantageous further training opportunities arise from the sub-requirements.

[0010] The core of the present invention lies in the fact that the compression bar is made of a metallic material and is produced by forming. The mechanical properties of the compression bar are largely achieved through the forming process and are a key factor in the particular suitability of the compression bar according to the invention for use in a transport anchor for double-wall elements. In particular, the forming process increases the mechanical strength and inherent stiffness of the compression bar. Compression bars according to the invention are therefore able to withstand greater forces, which leads to increased safety during the handling of the components. Load-induced deformations of the transport anchor, which are the cause of spalling on the concrete shells of the double-wall elements, remain minimal, and thus incidents of damage are rare.

[0011] The connection of the compression rod to the anchoring rods is achieved solely through the transmission of compressive and frictional forces at the contact surface. This type of connection does not alter the material structure of the anchoring legs, ensuring that the load is transferred evenly and reliably to the transport anchor along its entire length. This maximizes the load-bearing capacity of the transport anchor.

[0012] During the forming process, it is possible to give the compression bar its intended shape, with virtually no limitations regarding the shaping. The compression bar can even be manufactured as a monolith in a single forming process. This eliminates the need for subsequent machining of the compression bar in further processing steps. Consequently, transport anchors according to the invention can be manufactured with exceptionally low time and machine costs.

[0013] While the invention also includes forming the compression bars above the recrystallization limit of the material (hot forming), it is preferred to form the compression bars according to the invention below the recrystallization limit, i.e., by cold forming or semi-warm forming. The latter is preferably carried out at temperatures between 500°C and 900°C. In this way, increased strength of the compression bar is achieved with easier formability and higher formability.

[0014] Advantageously, a compression rod according to the invention is produced by die forging, since by using a suitable negative mold the product from the forging tool already corresponds to the finished compression rod and can be made available for its intended use.

[0015] During the forming process, it is possible to design the contact surfaces of the compression bar on the anchorage legs to be complementary to their circumference, with the contact surfaces partially encompassing the circumference of the anchorage legs. This increases the contact area available for force transmission, which counteracts local overloads and contributes to improved positioning of the compression bar heads on the anchorage legs.

[0016] In an advantageous embodiment of the invention, the load-bearing bracket is elastically pre-deformed such that, in a stress-free state, the lateral distance between the anchoring legs is less than the length of the compression rod to be inserted. This results in the anchoring legs spreading apart against the elastic restoring force of the load-bearing bracket when the compression rod is inserted into the transport anchor. In this way, the anchor head acts like a spring element, tensioning the anchoring legs against the compression rod heads. The compression rod is thereby clamped by the anchoring legs and fixed in this position. Particularly in combination with the enlarged contact surfaces, this leads to improved fastening of the compression rods to the anchoring legs without the need for additional fasteners.

[0017] The anchoring force with which a transport anchor according to the invention is anchored in a concrete component depends on the length and shape of the anchoring legs with which they engage the concrete component. According to an advantageous embodiment of the invention, the anchoring legs each have a wave-like longitudinal section in the region of their free ends. This increases the anchoring force with which a transport anchor engages a double-wall element and thus the safety against axial pull-out or breakout of the anchoring legs from the concrete of the shells of the double-wall elements. Alternatively, it is possible to design transport anchors according to the invention with wave-like end sections with a shorter anchoring length without compromising the minimum load-bearing capacity of the transport anchor.

[0018] The free ends of the anchoring legs are advantageously connected to each other by means of a cross brace. The cross brace ensures that the lateral spacing of the anchoring legs is maintained even at their ends before the double-wall elements are cast in concrete. At the same time, the cross brace reinforces the clamping effect exerted on the compression member by the anchoring legs, as already described.

[0019] The connection of the crossbar to the anchoring legs is preferably achieved by bending the ends of the crossbar over, thereby enclosing the anchoring legs. If the connection is made in the wave-like longitudinal section, the wave shape itself ensures safety against axial displacement of the crossbar on the anchoring legs without the need for any further measures.

[0020] Without being limited to this, the invention is explained in more detail below with reference to exemplary embodiments illustrated in the drawing, whereby further features and advantages of the invention become apparent. Where possible, identical reference numerals are used for identical or functionally equivalent features of different embodiments. Brief description of the drawings

[0021] It shows Fig. 1 an oblique view of a transport anchor according to the invention, Fig. 2 a partial section on a larger scale through the in Fig. 1 transport anchor shown along the line II - II there, Fig. 3 a side view on a larger scale on the in Fig. 1 Transport anchor shown in the area of ​​the end sections of the anchoring legs, Fig. 4 a side view of the in Fig. 1 shown pressure rod, Fig. 5 an axial view of the pressure rod head of the in Fig. 4 illustrated pressure rod, and Fig. 6 a top view of the in Fig. 1 shown compression rod. Description of the embodiments

[0022] Fig. Figure 1 shows a transport anchor 1 according to the invention in an oblique view. The transport anchor 1 has a load-bearing bracket 2, which is made entirely of ductile smooth steel or rolled ribbed steel and has a diameter of, for example, 14 mm. The load-bearing bracket 2 is symmetrical with respect to the longitudinal axis of the transport anchor 1 and has an upper bend 3 located on the axis of symmetry, about which the load-bearing bracket 2 with its two bracket halves is bent centrally by approximately 45°. At a distance from the upper bend 3, each bracket half has a lower bend 4, from which the two bracket halves extend parallel to each other to their free ends 6. The bracket section between the two lower bends 4 forms a V- or U-shaped anchor head 5, with the upper bend 3 serving as an attachment point for lifting gear of a lifting device.The longitudinal sections between the lower bending points 4 and the free ends 6 of the load stirrup 2 form parallel anchoring legs 7, which are embedded in the concrete of the opposing wall shells when a double wall element is manufactured. The anchor head 5 protrudes from the wall shells.

[0023] In the area of ​​the free ends 6, the anchoring legs 7 have a wave-shaped longitudinal section 8, which is Fig. 3 is shown on a larger scale.

[0024] The longitudinal section 8 has several opposing deflections oriented transversely to the plane of the transport anchor 1, which alternately form wave crests 8' and wave bases 8". This increases the anchoring force, which would otherwise require a greater anchoring length with straight anchoring legs. In the wave-shaped longitudinal section 8, the two anchoring legs 7 are connected to each other via a crossbar 9, for which purpose the ends of the crossbar 9 are each bent around the anchoring legs 7 by more than 180° in an eyelet-like manner. The crossbar 9 holds the free ends of the anchoring legs 7 at a defined lateral distance from each other.

[0025] How Fig. As can be seen further in Figure 1, a compression rod 10 is arranged between the two anchoring legs 7 of the load-bearing bracket 2, directly below the lower bending points 4. In the stress-free state of the load-bearing bracket 2, i.e., without the cross brace 9 and compression rod 10, a pre-deformation of the load-bearing bracket 2 in the area of ​​the upper bending point 3 is selected such that the lateral distance between the two lower bending points 4 is less than the length of the compression rod 10. As a result, when inserted into the transport anchor 1, the compression rod 10 elastically spreads the anchoring legs 7 in the plane of the transport anchor 1 against the restoring force of the anchor head 5 and holds them in position by the restoring forces activated in this process. At the same time, it is ensured that the intended distance between the anchoring legs 7 at the transition to the anchor head 5, determined by the length of the compression rod 10, is maintained.

[0026] The more precise design of the compression rod 10 is derived from the Fig. 4, Fig. 5 to Fig. 6. The compression bar 10 shown there is made of steel and was formed by die forging a rod-shaped blank at a temperature between 500°C and 900°C. The compression bar 10 produced in this way has a shaft 11, at each of the ends of which a compression bar head 12 is formed, wider than the shaft 11. The compression bar head 12 has an approximately circular outline in cross-section (see Fig. 5), wherein the side of a compression rod head 12 facing away from the shaft 11 is designed as a contact surface 13 with which the compression rod 10 rests in contact against the anchoring legs 7 of the transport anchor 1.

[0027] Especially the Fig. 2 and Fig.As shown in Figure 6, the contact surface 13 is simply curved to form a concave depression. In this way, the contact surface 13 forms a trough-shaped recess for the anchoring leg 7, in which part of its circumference rests. The partial engagement of the anchoring legs 7 by the contact surfaces 13 fixes the compression rod 10 relative to the load bracket 2 in the plane of the transport anchor 1.

[0028] The compression rod 10 is fixed in the direction of the longitudinal extension of the anchoring legs 7 by means of the narrowing of the load clamp 2 in the area of ​​the anchor head 5 following the lower bending points 4, and by the frictional engagement between the contact surfaces 13 and the circumference of the anchoring legs 7. The contact pressure to generate a frictional force comes from the restoring forces of the anchor head 5 already described, as well as from the clamping of the free ends 6 of the anchoring legs 7 by means of the cross strut 9. Reference symbol list 1 transport anchor 2 load bars 3 Upper bending point 4 Lower bending point 5 anchor head 6 Free End 7 anchor legs 8 Wavy longitudinal section 9 crossbar 10 pressure rod 11 shaft 12 Pressure rod head 13 Plant area QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 20 2012 001 342 U1

[0004] FR 3 112 566 A1

[0005] DE 10 2011 055 142 A1

[0006]

Claims

Transport anchor for concrete components, in particular for double wall elements made of concrete, comprising: a load stirrup (2) with two anchoring legs (7) arranged side by side at a lateral distance, which merge into one another to form a U-shaped or V-shaped anchor head (5), and a compression bar (10, 10') with end compression bar heads (12, 12'), wherein the compression bar (10, 10') extends transversely to the anchoring legs (7), is arranged between them and is connected to the anchoring legs (7) with its compression bar heads (12, 12') in a force-transmitting manner, characterized in that the compression bar (10, 10') is made of a metallic material and is manufactured by forming. Transport anchor according to claim 1, characterized in that the compression rod (10, 10') is manufactured by forming below the crystallization temperature of the material. Transport anchor according to claim 1 or 2, characterized in that the compression rod (10, 10') is manufactured by forming at a temperature between 500°C and 900°C. Transport anchor according to one of claims 1 to 3, characterized in that the compression rod (10, 10') is manufactured by die forging. Transport anchor according to one of claims 1 to 4, characterized in that the compression rod heads (12, 12') each have a contact surface (13) which is designed to be complementary to the outer circumference of the anchoring legs (7). Transport anchor according to one of claims 1 to 5, characterized in that the anchoring legs (7) are elastically prestressed against each other by the anchor head (5), so that the compression rod (10, 10') is held between the anchoring legs (7) by clamping and friction action. Transport anchor according to one of claims 1 to 6, characterized in that the free ends (6) of the anchoring legs (7) have a longitudinal section (8) which is wave-shaped. Transport anchor according to one of claims 1 to 7, characterized in that the free ends (6) of the anchoring legs (7) are connected to each other by a cross strut (9). Transport anchor according to claims 7 and 8, characterized in that the cross strut (9) is connected with its ends in the respective wave-like longitudinal section (8) of the anchoring legs (7). Transport anchor according to claim 8 or 9, characterized in that the crossbar (9) completely or partially encloses the anchoring legs (7) with its ends.

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