Method for producing a screw foundation

Abstract

The invention relates to a method for manufacturing a screw foundation for fastening elements in a substrate with a tubular body having a thread extending at least over a partial section of the tubular body, wherein a sheet metal strip is first provided and this sheet metal strip is spirally formed into the tubular body, wherein adjacent longitudinal edges on the sheet metal strip are connected to each other. It is provided that, prior to the spiral forming, at least section by section a longitudinal edge of the sheet metal strip (1) is formed in an L-shape, creating a web (2), and during or after the spiral forming the web (2) is continuously welded to the other longitudinal edge (4) of the sheet metal strip (1), with the web (2) forming the thread.

Description

[0001] The invention relates to a method for manufacturing a screw foundation for fastening elements in a substrate with a tubular body having a thread extending at least over a partial section of the tubular body, wherein a sheet metal strip is first provided and this sheet metal strip is spirally formed into the tubular body, wherein adjacent longitudinal edges on the sheet metal strip are connected to each other.

[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 for producing a screw foundation by pressure rolling is known from DE 10 2019 128 030 B3. In this method, a cylindrical tube is provided as the starting form, to which a conical front section tapering to an insertion tip is formed without the use of chips. 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 pressure rolling, and that the front section and the threaded outer contour are formed exclusively by pressure rolling. The screw foundation is thus produced solely by pressure 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] Another method of this type is known from DE 10 2022 113 309 B3. Both of these methods require a pipe as the starting material. Such pipes are not available in arbitrary sizes and are relatively expensive.

[0005] From DE 10 2023 101 066 B3, a method is known with the features of the preamble of claim 1 for manufacturing a screw component for use as a screw foundation or as part of a screw foundation for the ground, comprising a hollow body with a thread extending at least over a partial section of the hollow body, in which a steel sheet strip coated with a corrosion protection coating is used, the longitudinal edges of which are formed at least partially on both sides to create flange sections extending at least over a section along the longitudinal extent of the sheet strip. Subsequently, the sheet strip is spirally formed into a hollow body and joined, such that the formed flange sections partially overlap and form a thread extending at least over a partial section of the hollow body.In this process, the starting material is not a tube, but a strip of sheet metal. However, forming the flanges on both sides is material-intensive and requires a complex further forming process to create the hollow body. The point-bonded connection of adjacent flange sections occurs in the areas that form the threads in the finished component and must withstand the highest mechanical stress during the screwing-in process. This disadvantage is optionally mitigated by additionally joining the flange sections by crimping. This requires an additional forming step, which makes the process complex and precludes a continuous process sequence in a single machining tool.

[0006] The object of the invention is to create a solution with which screw foundations can be manufactured from sheet metal strips as a starting material in a material-saving and effective manner.

[0007] This problem is solved according to the invention in a method of the type described above by forming at least a longitudinal edge of the sheet metal strip in an L-shape before the spiral forming, forming a web, and by continuously welding the web to the other longitudinal edge of the sheet metal strip during or after the spiral forming, wherein the web forms the thread.

[0008] Such a process can be carried out in a single machining device. The continuous welding does not take place in the threaded area, but away from the outer edge of the thread-forming web, so that the weld joint is located outside the highest stress zone during the screwing process. Since a web only needs to be formed on one side, the process is significantly more material-efficient than the process known from DE 10 2023 101 066 B3, as narrower sheet metal strips can be used as the starting material.

[0009] Furthermore, it is planned that, in order to form a conically tapered front section of the screw foundation, the winding radius of the sheet metal strip is continuously increased from a small winding radius to a constant larger winding radius.

[0010] In a further embodiment, it is provided that the conically tapered front section is equipped with an insertion tip at the free end to facilitate screwing it into a substrate.

[0011] The insertion tip can be welded to the front section. Alternatively, the insertion tip can also be formed from the free end of the front section.

[0012] Furthermore, it is provided that the web height is varied during the L-shaped forming of the longitudinal edge of the sheet metal strip to create the web. Preferably, the web height increases from the front section 3a to a fixed value. The L-shaped angle is also variable and can therefore be greater or less than 90°.

[0013] In an advantageous embodiment, a contour for torque transmission is formed into a rear end of the tubular body by forming. This contour can, for example, be star-shaped and have internal and external teeth. Preferably, the contour is manufactured as described in DE 10 2022 113 309 B3. The contour is suitable for both a rotationally fixed connection with a screw-in tool and a rotationally fixed connection with a screw foundation extension.

[0014] To manufacture a screw foundation extension, it is preferably provided that at least a second sheet metal strip is supplied and this sheet metal strip is spirally formed into a second tubular body, wherein adjacent longitudinal edges on the sheet metal strip are connected to each other, wherein before the spiral forming, at least sectionally one longitudinal edge of the sheet metal strip is formed into an L-shape to form a web, and during or after the spiral forming, the web is continuously welded to the other longitudinal edge of the sheet metal strip and the web forms the thread, and that the two tubular ends of the second tubular body are each formed to form a contour for torque transmission.wherein the contour at one end of the second tubular body corresponds to the contour at the rear end of the first tubular body, and the contour at the other end of the second tubular body is designed such that the other end of the second tubular body can be inserted into or onto the rear end of the first tubular body in a force-fit and / or form-fit manner. Thus, a tubular screw foundation extension can also be manufactured from a strip of sheet metal.

[0015] The invention is explained in more detail below with reference to the drawing. The drawing shows a side view in each case. Fig. 1. The spiral forming of an already L-shaped sheet metal strip into a tubular body, Fig. 2 a view from the right Fig. 1, Fig. 3 the spiral forming of a rear area of ​​the tubular body from a flat sheet metal strip, Fig. 4 a view from the right Fig. 3 and in Fig. 5 a screw foundation made from the tubular body with a welded insertion tip.

[0016] The starting product for a process for manufacturing a screw foundation for fastening elements in a substrate is a flat sheet metal strip 1 as strip material, which consists of a steel suitable for the respective application.

[0017] In a first process step, this flat sheet metal strip 1 or this band is continuously formed into an L-shape, creating a web 2. This forming is preferably carried out by roll forming.

[0018] To form a tubular body with a conically tapered front section, this sheet metal strip 1 with an angled web 2 is spirally formed into a tubular body 3. The winding radius of the sheet metal strip 1 is continuously increased from a small winding radius to a constant larger winding radius, resulting in a conically tapered front section 3a and a cylindrical middle section 3b.

[0019] During or after the spiral forming, the web 2 is continuously welded to the other longitudinal edge 4 of the sheet metal strip 1. The weld seam is indicated by 5. The web 2, which thus runs in a spiral shape, forms the thread of the screw foundation 6 to be produced.

[0020] If the screw foundation 6 to be produced is not to have a thread in a cylindrical end section 3c, the following procedure sequence ( Fig. 3 and Fig.4) The sheet metal strip 1 or the band is fed in without prior L-shaped forming, i.e., flat, and wound spirally and welded, so that the cylindrical, threadless end section 3c of the screw foundation 6 is formed. During welding, the wound sections can be compressed axially.

[0021] The process steps described above are preferably carried out continuously in a single processing device, e.g., a three-roll bending machine with a roller assembly arranged in front of it in the direction of travel for forming the L-shaped web. The roller assembly can be deactivated to form the cylindrical end section 3c, i.e., pivoted away and / or moved laterally.

[0022] The front end of the front section 3a is then closed, preferably by welding on an insertion tip 7.

[0023] The rear end 3d is trimmed to form a flat end face oriented perpendicular to the longitudinal axis, and then a contour for torque transmission is formed into the rear end 3d by shaping, e.g. a star-shaped contour having internal and external teeth, which enables a rotationally fixed connection with a screw-in tool or a tubular screw foundation extension.

[0024] This tubular screw foundation extension is manufactured from a second sheet metal strip in an analogous manner, but without a conical front section, i.e., the winding radius during manufacturing remains constant. Reference symbol list: 1 strip of sheet metal 2 Bridge 3 tubular bodies 3a conical anterior section 3b Middle section 3c Final Section 3D rear end 4 Long edge 5 weld seam 6 screw foundations 7 Insertion tip

Claims

[1] Method for producing a screw foundation for fastening elements in a substrate with a tubular body having a thread extending over at least a partial section of the tubular body, wherein a sheet metal strip is first provided and this sheet metal strip is spirally formed into the tubular body, wherein adjacent longitudinal edges on the sheet metal strip are joined together, characterized by , that prior to the spiral forming, at least section by section a longitudinal edge of the sheet metal strip (1) is formed in an L-shape to form a web (2) and during or after the spiral forming the web (2) is continuously welded to the other longitudinal edge (4) of the sheet metal strip (1), wherein the web (2) forms the thread. [2] Method according to claim 1, characterized by, that to form a conically tapered front section (3a) of the screw foundation (6) the winding radius of the sheet metal strip (1) is continuously increased from a small winding radius to a constant larger winding radius. [3] Method according to claim 2, characterized by , that the conically tapered front section (3a) is provided with an insertion tip (7) at the free end. [4] Method according to claim 3, characterized by , that the insertion tip (7) is welded to the front section (3a). [5] Method according to one or more of claims 1 to 4, characterized by , that the web height is changed during the L-shaped forming of the longitudinal edge of the sheet metal strip (1) to form the web (2). [6] Method according to one or more of claims 1 to 5, characterized by , that a contour for torque transmission is formed into a rear end (3d) of the tubular body (3) by forming. [7] Procedure Claim 6, characterized by, that at least a second sheet metal strip is provided and this sheet metal strip is spirally formed into a second tubular body, wherein adjacent longitudinal edges on the sheet metal strip are joined together, wherein, prior to the spiral forming, at least sectionally, one longitudinal edge of the sheet metal strip is formed into an L-shape to form a web, and during or after the spiral forming, the web is continuously welded to the other longitudinal edge of the sheet metal strip, and the web forms the thread, and that the two tubular ends of the second tubular body are each formed to form a contour for torque transmission, wherein the contour at one end of the second tubular body corresponds to the contour at the rear end of the first tubular body, and the contour at the other end of the second tubular body is formed in such a way thatthat the other end of the second tubular body can be inserted into or onto the rear end of the first tubular body in a force-fit and / or form-fit manner.

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