METHOD FOR PRODUCING A SCREW FOUNDATION

Description

[0001] The invention relates to a method for producing a screw foundation for fastening elements in a substrate, in which at least one first cylindrical tube is provided as a first starting form and the first tube is provided at least partially adjacent to a front insertion end with a thread-like outer contour for screwing into the substrate, wherein a contour for a screwing tool is formed into a rear end of the first tube by forming.

[0002] Screw foundations are available in various designs. They can be designed at the rear end for inserting piles or rods, or alternatively, they can have a plate- or flange-like fastening element at the rear end to which other elements, e.g., frames or the like, can be attached.

[0003] A method with the features of the preamble of claim 1 is known from DE 10 2019 128 030 B3 and WO 2021 / 073927 A1. In this method for manufacturing a screw foundation for securing elements in the ground, a cylindrical tube is provided as the starting form, to which a conical front section tapering to an insertion tip is formed without machining. The front section is provided, at least in part, with a threaded outer contour for screwing into the ground. The essential feature of this method is that an inner contour for a screwing tool is formed into a rear end of the tube by die rolling, and that the front section and the threaded outer contour are formed exclusively by die rolling. The screw foundation is thus manufactured solely by die rolling, which reduces manufacturing effort and allows for the production of precise and reproducible components.Either the inner contour can be formed first, followed by the front section and the threaded outer contour, or vice versa. A drawn or welded tube can be used as the starting material.

[0004] In practice, it has been found that with a screw foundation produced in this way, the torque that can be transferred from the screwing tool to the inner contour of the screw foundation is limited, so that the screw foundation is less suitable for certain soil conditions or for particularly large penetration depths.

[0005] Further designs of screw foundations are known from the publications AT 16 939 U1, DE 85 30 749 U1, DE 202 20 515 U1, DE 10 2007 001 833 A1, DE 20 2019 105 845 U1 and EP 2 003 270 A2.

[0006] The object of the invention is to create a solution that provides an easy-to-manufacture screw foundation suitable for any soil conditions and preferably any penetration depth.

[0007] This problem is solved according to the invention in a method of the type described above by forming the rear tubular end of the first tube radially from the outside without an internal counter-form such that the contour is star-shaped, having internal and external teeth.

[0008] The contour at the rear end of the screw foundation is thus formed from the outside without the use of chips, creating both internal and external serrations. The external and internal serrations serve for a rotationally fixed connection with a screw-in tool having a complementary serration contour. The internal serration is suitable for the rotationally fixed retention of a tubular extension element, resulting in a screw foundation consisting of at least two parts. Furthermore, the internal serration is suitable for receiving a plate- or flange-type fastening element, which is equipped with a contour corresponding to the star-shaped contour. The star-shaped contour allows for the transmission of high torques, enabling screwing into substrates with various soil conditions. The star-shaped contour can be designed similarly to a screw drive profile with the standard designation internal Torx or Torx.External hexagon, but the number of teeth is arbitrary.

[0009] It is preferably provided that the rear end of the first tube is formed by several forming tools arranged on a common circumference and adjustable radially at the same rate. The forming tools can be, for example, pressing or stamping tools.

[0010] In most applications, a tapered front section, leading to an insertion tip, is formed onto the first tube without the use of cutting tools. This front section is at least partially provided with a threaded outer contour for screwing into the subsoil. Alternatively, the insertion tip can be omitted, and the front edge can be provided with a cutting edge similar to a hollow drill bit. In both cases, the longer or shorter threaded outer contour displaces and compacts the subsoil material during screwing, thus improving the anchoring of the screw foundation in the subsoil. If the insertion tip is open, depending on the subsoil properties, subsoil material also penetrates the front section of the screw foundation and pushes the outer surface of the screw foundation outwards, resulting in even better anchoring in the subsoil.

[0011] To simplify manufacturing, it is particularly preferred that the front section and the thread-like outer contour are formed exclusively by pressure rolling.

[0012] In a further preferred embodiment, the contour at the rear end of the first tube is clamped during the pressure rolling process. The clamping tool has a contour complementary to the star-shaped contour of the rear end. The strength and shaping of the contour at the rear tube end are further improved by the subsequent pressure applied during clamping, with the clamping tool preferably having a complementary internal mandrel.

[0013] In a particularly preferred embodiment, at least one second cylindrical tube is provided as a second starting form, and the two tubular ends of the second tube are each radially pressed in from the outside, forming a star-shaped contour with internal and external teeth and without an internal counter-form. The contour at one end of the second tube corresponds to the contour at the rear end of the first tube, and the contour at the other end of the second tube is designed such that the other end of the second tube can be inserted into or onto the rear end of the first tube in a force-fit and / or form-fit manner. The screw foundation then advantageously consists of at least two parts: the element produced from the first tube and at least one extension element that can be inserted into the rear of the aforementioned element in a rotationally fixed manner.Furthermore, the second pipe is also preferably provided, at least in some areas, with a thread-like outer contour for screwing into the substrate, e.g. by pressure rollers.

[0014] It can be advantageously provided that the nested ends of the first and second tubes are secured to one another by at least partial radial pressing in the area of ​​the contours. For example, spheres, hemispheres, or similar geometric bodies can be pressed into the external teeth of the outer contour using a suitable ring-shaped tool. These bodies form inwardly directed grooves in both nested star-shaped contours, which positively lock the two components together, thereby increasing the tensile and compressive load capacity of the screw foundation.

[0015] Finally, it is advantageous that the first pipe and / or at least one second pipe are made of Corten steel. The screw foundation is then particularly corrosion-resistant.

[0016] The invention is explained in more detail below with reference to the drawing. This shows in Fig. 1 a perspective view of a screw foundation, Fig. 2 an enlarged view of the rear end of the screw foundation according to Fig. 1 , Fig. 3 a perspective view of a cylindrical tube as the first starting form, Fig. 4 a side view of the rear tube end of the screw foundation with radially adjustable forming tools before forming, Fig. 5 one of the Fig. 4corresponding representation during the forming process, Fig. 6 a perspective view of a tubular extension element for forming a two-part screw foundation, Fig. 7 a perspective view of the front end of the extension element after Fig. 6 , Fig. 8 a perspective view of the rear end of the extension element according to Fig. 6 Fig. 9 a perspective exploded view of a two-part screw foundation before assembly, Fig. 10 an enlarged detail of the Fig. 9 Fig. 11 a perspective view of the two-part screw foundation, Fig. 12 a perspective view of the connection area of ​​the two-part screw foundation according to Fig. 11 and in Fig. 13 the connection area according to Fig. 12 with additional locking devices.

[0017] A one-piece screw foundation is in Fig. 1generally designated by 1. This screw foundation 1 exhibits the following characteristics in the exemplary embodiment: Fig. 1 The screw foundation 1 has a rear end 1a and a front end 1b. A star-shaped contour 2, described in more detail below, is formed into the rear, tubular end 1a. Axially adjacent to this star-shaped contour 2, the screw foundation 1 has a cylindrical section 1c and, adjoining this to the front, a front section 1d that tapers conically to an insertion point 3 at the front end 1b.

[0018] Both the front section 1d and the cylindrical area 1c are provided, at least partially, with a thread-like outer contour 4, which is preferably formed exclusively by pressure rolling. For a more detailed explanation, reference is made to publication DE 10 2019 128 030 B3.

[0019] To produce the screw foundation 1 described above, a first cylindrical pipe 5 is provided as the initial starting form. This pipe 5 can be a drawn or welded metal pipe.

[0020] The process begins by forming the star-shaped contour 2 into one end of the tube 5, which forms the rear end 1a of the screw foundation 1, such that it has an internal toothing 2a and an external toothing 2b. For this purpose, the rear end of the first tube 5 is inserted into a suitable forming device, which has several forming tools 6 arranged on a common circumference and which can be adjusted radially at the same rate ( Fig. 4These forming tools 6 are moved uniformly inwards towards the end of the first tube 5, so that without an internal counter-form, the star-shaped contour 2, having an internal toothing 2a and an external toothing 2b, is formed. The wall thickness of the first tube 5 does not change substantially. Unlike in Fig. 4 schematically represented, the outer contour of the forming tools 6 essentially corresponds to the contour of the external toothing 2a to be formed, the star-shaped contour 2.

[0021] After forming the star-shaped contour 2, the first tube 5 is preferably inserted with its rear end, featuring the star-shaped contour 2, into a complementarily designed clamping and holding tool of a flow forming machine. Subsequently, the first tube 5 is preferably flow forming into the Fig. 1The illustrated form of the finished screw foundation 1 is formed, with reference to German patent DE 10 2019 128 030 B3 for the execution of the flow forming processes. The tube 5 may be stretched first, but this step can also be omitted. After the flow forming process is complete, the insertion tip 3 is preferably closed in a suitable manner.

[0022] Alternatively, the screw foundation 1 can also be cylindrical over its entire length, i.e., it can have no insertion tip 3.

[0023] The star-shaped contour 2 at the rear end 1a of the screw foundation 1 has a dual function. The external toothing 2b serves for connection with a correspondingly complementary screw-in tool (not shown). The internal toothing 2a, on the other hand, serves for the force-fit and / or form-fit reception of a tubular extension element 7 to form a two-part screw foundation 1.

[0024] To produce the tubular extension element 7, a second cylindrical tube is provided as a second starting form. Both the front end 7a and the rear end 7b of the extension element 7 are machined in the same way as in the Figs. 4 and 5 shown, a star-shaped contour 8, 9 each with an internal toothing 8a, 9a and an external toothing 8b, 9b formed by radial pressing from the outside without an internal counter-form.

[0025] The contour 8 at the front end 7a of the extension element 7 is dimensioned such that the front end 7a can be inserted into the rear end 1a of the screw foundation 1 in a force-fit and / or form-fit manner. In contrast, the star-shaped contour 9 at the rear end 7b corresponds to the star-shaped contour 2 of the screw foundation 1, so that the rear end 7b of the extension element 7 is suitable either to be coupled to the screwing tool or to accommodate another extension element 7.

[0026] The cylindrical area 7c between the two ends 7a and 7b of the extension element 7 is preferably also provided with a thread-like outer contour 10 by means of pressure rollers.

[0027] If a two- or multi-part screw foundation 1 is to be used, which consists of the screw foundation 1 according to Fig. 1and consists of at least one extension element 7, the front end 7a of the extension element 7 is attached at the deployment site according to the sequence of Figs. 9 to 12 inserted into the rear end 1a of the screw foundation 1 in a form-fitting and / or force-fitting manner.

[0028] To achieve a secure connection, according to Fig. 13 It is provided that spheres 11 or hemispheres or similar geometric bodies are pressed into the external toothing 2a of the screw foundation 1 using a suitable ring-shaped tool, which form inwardly directed grooves in both the star-shaped contour 2 and the star-shaped contour 8, which secure the two components to each other in a form-fitting manner, thereby increasing the tensile-compressive load of the screw foundation.

[0029] The depicted star-shaped contours 2, 7 and 8 are only one example. The number of teeth shown can also be chosen differently.

[0030] A plate- or flange-like mounting element (not shown) can also be inserted into the rear end 1a or 7b and, if necessary, locked by means of balls 11, the mounting element being equipped with a contour corresponding to the star-shaped contour 8. The mounting element with the star-shaped contour can be manufactured, for example, by deep drawing. Other elements, e.g., frames or the like, can be attached to such a mounting element. Reference symbol list:

[0031] 1 Screw foundation 1a Rear end 1b Front end 1c Cylindrical section 1d Conical front section 2 Star-shaped contour 2a Internal toothing 2b External toothing 3 Lead-in tip 4 Threaded outer contour 5 First cylindrical tube 6 Forming tools 7 Tubular extension element 7a Front end 7b Rear end 7c Cylindrical section 8 Star-shaped contour 8a Internal toothing 8b External toothing 9 Star-shaped contour 9a Internal toothing 9b External toothing 10 Threaded outer contour 11 Balls

Claims

1. Method for producing a screw foundation (1) for fastening elements into a underlying surface, in which at least a first cylindrical tube (5) is provided as a first starting form and the first tube (5) is provided, adjacent to a front insertion end (1b), at least in some regions, with a thread-like external contour (4) for screwing into the underlying surface, wherein a contour (2) for a screw-in tool is formed in a rear end (1a) of the first tube (5) by shaping, characterized in that the rear tubular end (1a) of the first tube (5) is formed radially from the exterior without an internal counter form in such a way that the contour (2) is star-shaped, with internal and external toothing (2a, 2b).

2. Method according to claim 1, characterized in that the rear end (1a) of the first tube (5) is formed by multiple forming tools (6) that are arranged on a common circumference and are uniformly radially adjustable.

3. Method according to claim 1 or 2, characterized in that a conical front section (1d) tapering to an insertion tip (3) is formed on the first tube (5) without cutting, wherein the front section (1d) is provided at least in some regions with the thread-like external contour (4) for screwing into the underlying surface.

4. Method according to claim 3, characterized in that the front section (1d) and the thread-like external contour (4) are formed exclusively by pressure rolling.

5. Method according to claim 4, characterized in that during the pressure rolling, the contour (2) is clamped at the rear end (1a) of the first tube (5).

6. Method according to one or more of claims 1 to 5, characterized in that at least a second cylindrical tube is provided as a second starting form and in that the two tubular ends (7a, 7b) of the second tube are each pressed in radially from the outside, forming a star-shaped contour (8, 9) with an internal and external toothing (8a, 8b, 9a, 9b), without an internal counter form, wherein the contour (9) at one end (7b) of the second tube corresponds to the contour (2) at the rear end (1a) of the first tube (5) and the contour (8) at the other end (7a) of the second tube is formed such that the other end (7a) of the second tube can be inserted into or onto the rear end (1a) of the first tube (5) by force-fit and / or form-fit.

7. Method according to claim 6, characterized in that the ends (1a, 7a) of the first tube and second tube (5, 7) inserted inside one another are secured to one another by at least partial radial pressing in the region of the contours (2, 8).

8. Method according to one or more of claims 1 to 7, characterized in that the first tube (5) is made of Corten steel.

9. Method according to clai 6, 7 or 8, characterized in that the at least one second tube is made of Corten steel.