Method for producing an inner tube for a supporting device

Abstract

The invention relates to a method for producing an inner tube (4) for a supporting device for dissipating building loads (F) caused by a ceiling formwork (1) or the like, comprising: forming a flat metal sheet to create a thread structure comprising a plurality of external thread sections (8a - 8c); profiling the flat metal sheet provided with the thread structure to form a tube geometry which is round in envelope cross section; connecting the mutually facing butting edges in a form-fitting or integrally bonded manner to form a closed profiled tube. The invention also relates to a supporting device having an inner tube produced in this way.

Description

Reference to related applications

[0001] The present invention relates to a method for manufacturing an inner tube for a support device for transferring structural loads caused by a ceiling formwork or the like to a stable floor surface, comprising at least one such inner tube arranged telescopically in an outer tube with an external thread which interacts with an internal thread of an adjusting nut rotatably arranged on the outer tube for length adjustment.

[0002] The scope of application of the present invention extends to structural engineering applications in which structural loads caused by a slab formwork, a precast concrete element, an overhead installation unit, or the like, need to be supported against a stable base of a building until these elements are permanently installed. The support device can then be removed.

[0003] Typically, for example, supporting a ceiling during the installation of an intermediate floor in a building, a large number of adjacent support structures of the type relevant here are used. These are also called ceiling supports and are usually adjustable in length to accommodate different floor heights depending on the building design. State of the art

[0004] DE 195 03 296 A1 discloses a telescopic support device of the type of interest here. Length adjustment is achieved using a threaded drive with an external thread and a corresponding nut. The external thread is applied to the inner tube of the telescopic support device, and the threaded nut is rotatably mounted on the outer tube. Turning the threaded nut extends or retracts the inner tube relative to the outer tube to adjust its length. WO 2015 / 200325 A1 discloses, by way of example, a method for manufacturing an inner tube in which the opposing butt edges are aligned and joined to form a closed profile tube.

[0005] The threaded drive of this previously known support device has a helix angle outside the self-locking range. The load exerts a torque on the threaded nut, which is absorbed by a frictional engagement acting on the nut outside the thread. This frictional engagement is formed between a conical surface on the threaded nut and a funnel-shaped section of the outer tube.

[0006] Thanks to the threaded drive, stepless length adjustment of the support device is possible, eliminating the need for additional spacer blocks and wedges for length adjustment. This allows for relatively quick assembly and disassembly of such support devices.

[0007] However, this advantage of stepless adjustability is accompanied by the manufacturing challenge of providing the inner tube with an external thread along its entire length for interaction with the threaded nut, which generally requires complex machining. Currently, an extruded light metal tube is typically used as the semi-finished product.

[0008] It is therefore the object of the present invention to provide a method for manufacturing a statically stable inner tube for a support device of interest here, the external thread of which can be produced in a manufacturing-technically simple manner. Disclosure of the invention

[0009] The problem is solved by claim 1 with regard to a method for the efficient manufacture of an inner tube provided with an external thread.

[0010] The invention includes the process engineering teaching that the forming-technical production of the inner tube for a support device for transferring structural loads caused by a ceiling formwork or the like comprises the following manufacturing steps: Forming a flat sheet to produce a thread structure comprising several external thread sections, profiling the flat sheet provided with the thread structure to a round tube geometry in the cross-section, form-fitting or material-fitting joining of the mutually facing butt edges to form a closed profile tube.

[0011] The inner tube produced according to the invention offers the manufacturing advantage that the external thread on the inner tube can be produced without machining, by creating it in a preceding forming step before the actual tube profiling. Since sheet metal is used, the inner tube can also be made particularly lightweight, ensuring quick and easy handling. For example, a support device with a support length of 4 m in its fully extended telescopic state weighs less than 20 kg. The support device designed according to the invention can preferably be continuously adjusted in length ranges between 3 and 5 m and can bear the structural loads of a B and D column according to DIN EN 1065.

[0012] Preferably, pre-curved thread bends are produced in the flat sheet metal by forming the external thread sections using bending. This facilitates subsequent pipe bending, and the pre-formed external thread sections thus precisely complement each other to form a continuous thread. Only the areas between the thread sections then need to be bent to achieve the desired round pipe geometry. For the purposes of this application, a round pipe geometry is understood to be a geometry that is essentially circular in its cross-section. This may also include segmental deviations from a circular shape. The thread structure is preferably designed as a round thread, trapezoidal thread, or a combination thereof. This allows for both a high load-bearing capacity and a wear-resistant threaded drive.

[0013] The threaded sections should be continuous in the longitudinal direction, as the tools cannot be lifted from the workpiece during forming, particularly bending. This forming process allows for advantageously strong work hardening of the formed material areas, thus giving the resulting inner tube high stability. Longitudinal welding, brazing, or flanging of the butt edges can be performed after profiling, preferably using high-frequency welding or laser welding. The minimum feed rates must be adjusted accordingly for the overall process.

[0014] According to a preferred embodiment, the inner tube and / or the outer tube is manufactured from strip steel in a continuous forming and welding process, with individual tube sections being produced by cutting to length. The support device, preferably made of steel, is capable of withstanding higher loads than comparable continuously adjustable light metal support devices. This is also due to the work hardening achieved through cold forming – particularly in the threaded area. Furthermore, the thread can be produced continuously without the need for machining. By using cold forming processes for thread production and also for tube profiling, a particularly time-efficient manufacturing process for support devices can be achieved.

[0015] The inner tube is preferably used in a support device for transferring structural loads caused by a ceiling formwork or the like onto a floor surface, comprising an inner tube arranged telescopically in an outer tube with an external thread, which interacts with an internal thread of an adjusting nut rotatably arranged on the outer tube for stepless length adjustment.

[0016] The lengths of the inner and outer tubes can be matched so that the total telescoped length is between 1.5 and 6 meters, preferably between 3 and 5 meters.

[0017] Preferably, the inner tube formed from sheet metal is provided with a longitudinal weld, solder or flange connecting the butt edges to form a closed profile tube.

[0018] One measure proposes that the outer tube formed from sheet metal should also be provided with a longitudinal weld or flanging connecting the butt edges, in order to easily form a reliably closed profile tube.

[0019] The starting material for the forming process for the production of the inner tube and / or the outer tube is preferably pre-galvanized strip steel with a sheet thickness between 1.5 and 5 millimeters, in particular between 2 and 4 millimeters as an optimum between stability, manufacturability and lightness.

[0020] One proposed measure involves using a slip ring disc positioned at the end face of the outer tube in the area of ​​the adjusting nut. This disc is equipped with several guide pins extending axially away from the nut. These guide pins engage with profile sections of the outer tube, thus preventing the slip ring disc from rotating. The slip ring disc serves as a bearing surface for the adjusting nut and acts as an end component attached to the outer tube.

[0021] For the interaction between the grinding ring disc and the adjusting nut, the latter consists of a threaded section and an axially adjoining groove section for rotatable mounting on the grinding ring disc and thus on the outer tube. The adjusting nut has several outwardly extending cams, which allow operation by hand or with an additional wrench. Detailed description based on drawing

[0022] Further measures improving the invention are described in more detail below, together with a description of a preferred embodiment of the invention, with reference to the figures. The figures show: Fig. 1 a perspective view of a telescopic support device in the assembled state, Fig. 2 a perspective view of the sheet metal material of the inner tube before profiling, Fig. 3 a perspective view of the inner tube after profiling, Fig. 4 a cross-sectional view of the outer tube associated with the inner tube, Fig. 5 a perspective view of a slip ring disc for anti-rotation protection, Fig. 6 a perspective view of an adjusting nut.

[0023] According to Fig. 1A support device for transferring structural loads F caused by a ceiling formwork onto a floor surface 2 essentially consists of an inner tube 4 arranged telescopically with an outer tube 3, which is infinitely adjustable in length by means of a threaded drive by means of an adjusting nut 5 arranged rotatably on the outer tube 3.

[0024] The support device comprises, for placement against the ceiling formwork 1, a head plate 6 attached to the inner tube 4 at the distal end and a base plate 7 arranged at the distal end of the outer tube 3.

[0025] According to Fig. 2 The inner tube 4 is manufactured from a sheet metal material that is flat in its initial form, in which a thread structure comprising several external thread sections 8a - 8c is created by bending.

[0026] After Fig. 3The pre-processed sheet metal is then formed into a round tube geometry. The butt edges coming into contact with each other are finally joined by a longitudinal weld 9 to form a closed tube profile. Since the threaded sections 8a to 8c were pre-formed with a curve in the previous manufacturing step, the unprofiled tube area between the threaded sections is essentially rounded during the profiling to the round tube geometry. As a result, the profile cross-section deviates slightly from a perfectly circular geometry.

[0027] In Fig. 4 The cross-section of the outer tube 3, which is also not circular, is illustrated; it is also profiled by bending from a flat sheet material and is subsequently welded longitudinally.

[0028] The in Fig. 5The illustrated slip ring disc 10 engages with its axially extending guide pins 11a to 11c in the shoulder pockets formed by the profile cross-section of the outer tube 3 (not shown here) to prevent rotation of the slip ring disc. The anti-rotation of the outer tube 3 relative to the inner tube 4 is achieved by a profile cross-section that deviates from a circular shape, which can, for example, be cloverleaf-shaped or similar.

[0029] The in Fig. 6 The illustrated adjusting nut 12 consists of a threaded section 13, to which a groove section 14 is attached in the axial direction. The groove section 14 interacts with the grinding ring disc 10 described above.

[0030] The invention is not limited to the preferred embodiment described above. Rather, variations thereof are also conceivable, which are included within the scope of protection of the following claims. For example, it is also possible that more or fewer than three threaded sections are arranged distributed around the circumference of the inner tube, depending on the load and the thread drive ratio. Reference symbol list

[0031] 1 Ceiling formwork 2 Floor surface 3 Outer pipe 4 Inner pipe 5 Adjusting nut 6 Head plate 7 Base plate 8 External thread (sections) 9 Longitudinal weld 10 Grinding ring washer 11 Guide pin 12 Actuating cam 13 Internal thread 14 Groove section F Construction load

Claims

1. A method for producing an inner tube (4) for a supporting device for transferring structural loads (F) caused by a slab formwork (1) or the like, comprising the following manufacturing steps: - forming a flat sheet to produce a thread structure comprising a plurality of external thread sections (8a-8c), - profiling the flat sheet provided with the thread structure to form a tubular geometry that is round in the envelope cross-section, - joining the mutually facing abutting edges in interlocking or integrally bonded manner to form a closed profile tube.

2. The method according to Claim 1, characterized in that precurved threads arcs are produced in the flat sheet as a result of the forming.

3. The method according to Claim 1, characterized in that forming by way of cold working is performed by bending.

4. The method according to Claim 1 or 3, characterized in that profiling to form the tubular geometry is likewise carried out by way of cold working by bending.

5. The method according to Claim 1, characterized in that the inner tube (4) and / or the outer tube (3) is / are produced in a continuous forming and joining process starting from a strip steel material, wherein individual tube pieces are produced by cutting to length.

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