Method and system with a screw fixation of a component with a screw channel

Description

[0001] The invention relates to a method for securing components using a screw that is screwed into a screw channel of one of the components. The invention further relates to a system comprising the component and a screw.

[0002] Scaffolding for the construction industry requires the assembly of a large number of mostly metal components, for example, to create a staircase for a scaffolding. To construct a staircase, a stringer profile is usually screwed to the side of the step and platform components, which are often equipped with screw channels for this purpose.

[0003] The documents US4395080A, US5156416A, EP2808565A1 and DE202014005332U1 disclose components that can be fixed by means of screws.

[0004] The documents DE 10 2013210363 A1 and EP 1635077 A1 also disclose methods and systems for fixing components using a screw.

[0005] The object of the invention is to provide a further developed method and component.

[0006] To achieve this object, a method according to claim 1 and a system according to claim 3 are used. Advantageous embodiments emerge from the subclaims.

[0007] To achieve this aim, a method is provided for fixing another component to a component using a metric or imperial screw. The component comprises a screw channel which is delimited in cross-section by an inner circumferential surface. The inner circumferential surface has an edge which extends parallel to a central axis of the screw channel and, when viewed in cross-section, projects towards the central axis. The screw is screwed into the screw channel in the direction of the central axis to fix the two components. In this way, an internal thread is created in the edge, i.e. the edge has interruptions so that a screwed-in screw can be fixed in the direction of the central axis. In particular, the edge is a corner or point when viewed in cross-section. In an alternative or additional embodiment, the edge is blunt or rounded.It is also possible in principle that the edge is formed by an elongated, rectangular body and / or the edge is one of two corners of a rectangular body that are at the same distance from the central axis.

[0008] Mathematically speaking, an edge extends linearly. When the term "edge" is used in a context that requires a three-dimensional shape, this can refer to an edge body in which the edge is encompassed including a part or region of the screw channel or the inner lateral surface extending from the edge, i.e., a part or region extending radially away from the central axis.

[0009] A metric or inch screw is a screw designed to be screwed into a metric or inch nut thread. A metric or inch screw is not a specialty screw, but is mass-produced according to DIN standards and is readily available on the market. A preferred example is DIN EN ISO 4762 or DIN 912 VG, as well as DIN 13-1.

[0010] An edge in which an internal thread is created by turning the screw into the screw channel, previously had no internal thread. By turning, i.e. screwing, the metric or imperial screw into the screw channel with the edge protruding towards the central axis, material of the edge or an edge body is displaced so that the screw creates a form-fitting connection viewed in the direction of the central axis. The edge is therefore deformed by the metric or imperial external thread of the screw such that the edge, viewed in the direction of the central axis, has recesses at regular intervals into which the external thread of the screw engages. In one embodiment, the edge belongs to an elongated edge body viewed in cross-section and which extends radially in the direction of the longitudinal extent of the edge body towards the central axis. According to the invention, the edge, viewed in cross-section, is the point with the shortest distance to the central axis.

[0011] By eliminating the need for an internal thread, the component can be manufactured with particularly low effort. Furthermore, because metric or inch screws are used, the additional costs and effort required to manufacture special screws are eliminated.

[0012] A further advantage is that the resulting screw fixation can be removed and re-attached particularly reliably. Tests have shown that the screw fixation can be removed and re-attached at least two to three times without any significant loss of strength. The internal thread in the edge created by deformation using the metric or imperial screw is particularly robust.

[0013] Even if the use of the fixed components does not require disassembly during normal operation, this still opens up the possibility of particularly simple repair. For example, if the components are used to construct a scaffolding staircase, a damaged step may require repair. Previously, a staircase was repaired by cutting off the defective component and welding on a replacement component. The present invention makes it possible to simply remove the defective component or another component by unscrewing the screw and, after replacing it with a replacement component, to reattach it by screwing in the same screw.

[0014] In one embodiment, manual force, i.e., hand force, is sufficient to screw the screw into the screw channel. Typically, a screwdriver or Allen key is used to screw the screw in manually. The screwing-in process involves first turning the screw into the screw channel, which creates the internal thread in the edge. This enables particularly simple installation and, at the same time, a particularly high load-bearing capacity of the screw fixation.

[0015] A further aspect of the invention relates to a system according to claim 3, comprising a component with a screw channel for fixing by means of a screw, wherein the screw channel is delimited in cross-section by an inner circumferential surface and the inner circumferential surface has an edge which extends parallel to a central axis of the screw channel and, viewed in cross-section, projects towards the central axis, in particular radially. The component is thus manufactured with particularly little effort and a further component is particularly easily fixed to the component by means of the screw. The edge has no recesses for engagement of a screw, i.e. an external thread of the screw. The edge enables an internal thread to be created in the edge or an edge body which encompasses the edge when a metric or imperial screw is turned, i.e. screwed, into the screw channel in the direction of the central axis for fixing.An edge that projects towards the central axis when viewed in cross-section has the smallest distance to the central axis of the entire inner surface.

[0016] In one embodiment, the inner surface has a closed cross-section. This allows for an internal thread or recesses for engaging an external screw thread to be created particularly reliably in the edge when a metric or imperial screw is screwed into the screw channel.

[0017] A closed cross-sectional surface has a completely closed contour around the central axis. A closed contour is not a C-shape. A closed contour has no gap for the screw channel to expand when the screw is inserted.

[0018] By providing a closed cross-sectional surface, the edge of the screw cannot deflect when screwed in. This enables particularly reliable creation of an internal thread or corresponding recesses in the edge by deforming the edge and displacing material from the edge. The internal thread created in this way, or recesses spaced along the center axis as a countercontour to the external thread of the metric or imperial screw, are therefore particularly robust and dimensionally stable. This allows the screw to be loosened and tightened (i.e., screwed in) at least two or three times without significantly reducing the strength of the screw fixation.

[0019] In one embodiment, the screw channel provides a clearance on both sides of the edge or an edge body in the cross-section. This clearance allows material from the edge to be displaced laterally by the external thread of the screw during screwing in. This allows for particularly easy screwing in of the screw and reliable creation of an internal thread in the edge.

[0020] According to the invention, at least three and in particular at most eight edges are provided, which extend parallel to the central axis and, viewed in cross-section, protrude toward the central axis. By providing three edges, forces can be evenly absorbed by the screw fixation. Preferably, at least four edges are provided. This ensures particularly robust screw fixation, especially under the typical loads encountered in scaffolding. In one embodiment, a maximum of fifteen edges are provided. This allows sufficient space for displaced material when screwing in the screw.

[0021] In one embodiment, exactly four edges are provided. Here, too, these are edges that run parallel to the central axis and, when viewed in cross-section, protrude towards the central axis. This allows material to be saved while still maintaining a robust screw fixation. It was recognized that with exactly four edges, forces of all orientations, such as diagonal forces, can be reliably absorbed by the screw fixation and the edges. Compared to a full-circumferential internal thread, providing a screw channel with exactly four edges enables a lightweight construction without a prefabricated internal thread, and particularly lightweight components with low manufacturing and assembly costs can be produced.

[0022] In one embodiment, the edges are identical in construction. Identical edges are usually at least identical in shape and / or have the same dimensions. This allows for particularly uniform screwing along the central axis and particularly uniform absorption of forces through the screw fixation.

[0023] In particular, edge bodies each having an edge including a part or region of the screw channel or the inner circumferential surface extending toward the central axis are structurally identical. Preferably, the part or region is triangular. In one embodiment, the part or region each extends from an edge to a largest inner diameter of the inner circumferential surface. The edge geometry is the same for edges or edge bodies of identical construction or identical shape.

[0024] In one embodiment, the edges are at an identical distance from the center axis. This way, the screw is automatically centered along the center axis by the edges.

[0025] In one embodiment, the edges are arranged around the central axis at preferably identical angular distances from one another. This allows for particularly uniform screwing along the central axis and particularly uniform absorption of forces by the screw fixation.

[0026] In one embodiment, the entire inner surface is point-symmetrical to the central axis when viewed in cross-section. The cross-sectional contour of the inner surface is thus projected onto itself at certain angular positions relative to the central axis, particularly at 0°, 90°, 180°, and 270°. This enables particularly reliable and uniform force absorption through the screw fixation.

[0027] In particular, the inner lateral surface or edge body, viewed in cross-section, is mirror-symmetrical to a plane on which the central axis and the edge lie. Preferably, the inner lateral surface, viewed in cross-section, is mirror-symmetrical to another plane that is perpendicular to the aforementioned plane and on which the central axis also lies. This enables particularly uniform screwing along the central axis and particularly uniform absorption of forces through the screw fixation.

[0028] In one embodiment, the edge is formed by two flat, angled surfaces that meet to form the edge. This allows for a uniform internal thread to be created when the screw is screwed in. The internal thread comprises a plurality of recesses spaced apart from one another in the direction of the central axis, extending from one surface to the other, angled surface. Each recess interrupts the edge, i.e., the otherwise preferably straight edge profile.

[0029] In one embodiment, the screw channel and / or the inner surface are designed such that screwing a metric or imperial screw into the screw channel in the direction of the central axis creates an internal thread in the form of recesses in the edge or an edge body. The component can thus be produced with particularly low manufacturing effort.

[0030] The recesses each have the counter-contour to a flank or at least an outer part of the flank of the external thread of the metric or imperial screw. In one embodiment, the recess created in the edge is triangular or trapezoidal when viewed in longitudinal section along the central axis. In one embodiment, the internal thread in the edge or the edge body has a zigzag shape.

[0031] In one embodiment, the component was manufactured by extrusion. A component with a screw channel that has a constant cross-sectional contour along the central axis can thus be manufactured particularly easily and with relatively little effort. According to the invention, the component is made of aluminum or fiber-reinforced plastic. Additionally, the component can be made of steel, in particular cast steel or stainless steel, e.g., 1.4301 or 1.4310.

[0032] In one embodiment, the component is a step or a platform component for a scaffolding stairway. A lightweight stairway can thus be provided for a scaffolding with particularly low effort.

[0033] The system comprises the component according to one of the embodiments described above. The system further comprises a metric or imperial screw. The system is designed such that the metric or imperial screw can be turned into the screw channel of the component in the direction of the central axis to fix the component, thus creating an internal thread in the edge or an edge body.

[0034] An inch screw, for example, has a so-called Whitworth thread. As already mentioned, a metric and inch screw are configured to be screwed into a female thread or a nut. A metric or inch screw is not a sheet metal screw, a universal screw, a drywall screw, or a wood screw. The listed screws are not configured to be screwed into a metric or inch female thread.

[0035] The preferred metric or imperial screw is a steel construction screw. This allows for a particularly cost-effective screw fixation.

[0036] Particularly preferably, the metric or imperial screw is a full-thread screw. This allows the screw to be screwed into the component or another component until it stops. For example, another component that is attached to the component by means of the screw can be secured against the component under preload.

[0037] In one embodiment, the distance from the edge to the central axis is at least 70%, preferably at least 81%, particularly preferably at least 83% and / or at most 95%, preferably at most 90%, of half the nominal external thread diameter of the screw. Half the nominal external thread diameter corresponds to a nominal external thread radius. The distance from the edge to the central axis is to be measured from a point on the edge that is closest to the central axis, preferably from an inwardly projecting tip. Manual screwing in of the screw and sufficient load-bearing capacity can be achieved particularly reliably in this way. The distance from the edge to the central axis is the smallest distance that can be measured between the edge and the central axis, viewed in cross-section. In particular, the distance corresponds to the radial distance.From a distance of at least 81% from the edge to the center axis, the core of the screw thread does not need to displace any material from the edge or the edge body, thus enabling particularly easy screwing in. Up to a distance of less than 81% from the edge to the center axis, which is provided for in one design, screwing in is more difficult, but a particularly high strength of the screw connection is achieved.

[0038] In particular, the recesses in the edge, which were created by screwing in the screw and which form the internal thread, have a depth of at least 5%, preferably 10%, and / or at most 30%, preferably at most 20%, of half the nominal external thread diameter of the screw. This allows the internal thread to be formed by displacing and reshaping the material of the edge, with the displaced material being able to escape into the free space.

[0039] In one embodiment, the distance from the edge to the central axis is at least 102% and / or at most 117% or 108% of half the external thread core diameter of the screw. Half the external thread core diameter corresponds to an external thread core radius. Deformation of the edge material therefore does not noticeably hinder screwing in. The distance from the edge to the central axis is the smallest distance that can be measured between the edge and the central axis, viewed in cross-section. In particular, the distance corresponds to the radial distance.

[0040] In one embodiment, the distance from the edge to the center axis is at least 86% and / or at most 100% of half the external thread core diameter of the screw. This allows for a particularly high strength of the screw connection.

[0041] Exemplary embodiments of the invention are explained in more detail below, also with reference to figures. Features of the exemplary embodiments and other alternative or supplementary embodiments described below can be combined within the scope defined by the appended claims.

[0042] They show: Figure 1: Schematic cross-sectional view of a section of a component with a screw channel for securing a screw; Figure 2: Schematic view of a metric screw in longitudinal section; Figure 3: Isometric view of a component to which another component is fixed by means of screws.

[0043] The Figure 1shows a section of a component 1 with a screw channel 4 in cross-section. The screw channel 4 is defined and limited by an inner surface 5. The inner surface 5 forms four edges 6, which extend parallel to a central axis 7 of the screw channel 4 and, viewed in cross-section, protrude towards the central axis 7. The central axis 7 runs like the cross-sectional profile in Figure 1 in line of sight.

[0044] The contour of the inner lateral surface 5 surrounds the central axis 7, which, viewed in cross section, forms the center of symmetry for the particularly point-symmetrical contour of the lateral surface 5. In Figure 1 A horizontal plane of symmetry 14 and a vertical plane of symmetry 15 perpendicular thereto are also shown. The inner lateral surface 5 is preferably mirror-symmetrical to the horizontal plane of symmetry 14 and / or the vertical plane of symmetry 15.

[0045] The four edges 6 are identical in construction, have an identical distance 11 from the central axis 7, and are arranged at identical angular intervals of 90° from one another around the central axis 7. Each edge 6 is preferably mirror-symmetrical to the horizontal plane of symmetry 14 or the vertical plane of symmetry 15. Each edge 6 is formed by two flat and mutually angled surfaces 9, 10, which meet to form the respective edge 6.

[0046] In one embodiment, an angle between two flat surfaces 9, 10 which form the edge 6 is at least 10° and / or at most 190°. An internal thread can thus be reliably produced. In particular, the two surfaces 9, 10 belong to one edge body. In one embodiment, the edge 6 is formed exclusively by a substantially triangular edge body in which the edge 6, viewed in cross-section, is the only point with the shortest distance to the central axis, i.e. there are no two points or two edges of the same edge body with the same distance to the central axis, which is simultaneously the shortest distance of the edge body to the central axis. In one embodiment, the edge 6 lies on a longitudinal axis in the longitudinal extension of the edge body, which projects in the direction of the longitudinal axis towards the central axis, wherein the longitudinal axis runs substantially, in particular, centrally to the transverse extension of the edge body.

[0047] In one embodiment, the angle 16 between a plane of symmetry 14 and a flat surface 10 forming the edge 6 is at least 10° and / or at most 80°. In an example not shown, the angle 16 can generally be 0°, so that, for example, a cuboid-shaped block is provided which, viewed in cross-section, provides a free space 8 on each side adjacent to an edge.

[0048] The screw channel 4 of the Figure 1 is configured for fixing with a metric screw 3 of size M8 as the external thread nominal diameter 12, as exemplified in Figure 2Shown in longitudinal section. The external thread core diameter 13 for an M8 screw is 6.47 mm according to DIN 13-1. A DIN 912 cylinder head screw VG with a hexagon socket 17 is preferred. The screw 3 can thus be screwed very tightly against an adjacent wall of the other component 2, which would otherwise obstruct the application of a tool for the screw.

[0049] The screw channel 4 of the Figure 1 is basically scalable, so that a proportionally smaller or larger screw channel 4 for metric or inch screws 3 with a correspondingly larger or smaller external thread nominal diameter 12 can be used in the same way.

[0050] The embodiment described below with a screw channel 4 as Figure 1 shown and a matching screw 3 as shown in Figure 2 shown is therefore to be understood purely as an example.

[0051] The four edges 6 of the screw channel 4 of the Figure 1 all have a distance 11 of in particular approximately 3.4 mm from the central axis 7. The edges 6 have the smallest distance from the central axis 7 of the entire inner circumferential surface 5. The flat surfaces 9, 10 preferably enclose an angle of approximately 90° to one another. At a radial distance 18 of in particular approximately 1 mm from the edge 6 in relation to the central axis 7, an arcuate section 19 adjoins the flat surfaces 9, 10. Preferably, the arcuate section 19 has a radius of approximately 1.5 mm and forms part of the free space 8. In particular, the arcuate section 19 merges into a less curved contour section 20, which likewise defines and delimits part of the free space 8. In particular, the contour section 20 has a center axis distance 21 from the central axis 7 of approximately 6.7 mm.

[0052] In particular, the screw channel 4 has approximately the cross-sectional shape of a four-leaf clover.

[0053] Preferably, the screw channel 4 is incorporated into a substantially cylindrical base body, which in particular has an outer diameter 22 of at least 15 mm and / or at most 25 mm, particularly preferably approximately 17 mm. In particular, the base body is arranged below or tangentially to a plate-shaped region of the component. A component with a screw channel 4 can thus be manufactured particularly easily using a lightweight construction.

[0054] In one embodiment, the inner surface 5 is closed and has a minimum thickness of 20% of the nominal external thread diameter 12 of the screw 3. For an M8 screw, the minimum thickness is then, for example, 1.6 mm. Because the inner surface 5 is closed, a particularly low minimum thickness can be used while still meeting the mechanical requirements. This allows for savings in material and weight.

[0055] In particular, the screw 3 has a nominal length 23 of at least 20 mm and / or at most 100 mm. A nominal length 23 of 30 mm is particularly preferred. In particular, the screw 3 is an M8x30 mm screw. The screw is preferably made of steel, in particular with a galvanized surface.

[0056] In Figure 3 Examples of the component 1 and the further component 2 are shown, which in the fixed state in this exemplary embodiment form a staircase for a scaffold or a part thereof.

[0057] In particular, the further component 2 is a stringer profile and / or the component 1 is a step and / or platform component. The stringer profile is fixed by means of screws 3, in particular the Figure 2, fixed laterally to a step and / or platform component. For this purpose, a screw 3 is inserted through a through-hole in the additional component 2 and screwed into the screw channel 4 of the component 1, creating an internal thread in the edges 6.

[0058] In Figure 3 The center axes 7 for two screw channels 4 each are shown as an example for a platform component and a step component. Therefore, just two screw channels 4 are sufficient to sufficiently secure the cheek profile to a step component.

[0059] The Figure 3 The platform is made up of several platform components. Anti-slip ribs 24, which are also visible in the enlargement of the Figure 1 are provided on the accessible surfaces to prevent a person from slipping.

[0060] In one embodiment, the edge 6 is formed by two mutually angled surfaces 9, 10 which meet to form the edge 6. Viewed in cross-section to the central axis 7, the surface 9 meets the edge 6 at the same angular difference as the other surface 10, wherein the angular difference is measured between the respective surface 9, 10 and a plane 14 which runs through the central axis 7 and the edge 6. The plane 14 is therefore the plane of symmetry for the extension of the surfaces 9, 10 when they meet in the edge 6. This enables the formation of a triangular edge body so that the screw, starting from the edge 6, can cut radially outwards into the screw channel 4 to create the internal thread.

[0061] In one embodiment (viewed in cross-section to the central axis 7), the edge 6 is formed by two intersecting surfaces 9, 10 which run symmetrically to a plane of symmetry 14, wherein the plane of symmetry 14 runs through the central axis 7 and the edge 6. The central axis 7 and the edge 6 therefore lie in the plane of symmetry 14. Cutting the internal thread by the screw can thus be made possible with a steadily increasing rotational resistance for the user. Initially, the rotational resistance is comparatively low due to the edge 6 consisting of two intersecting surfaces 9, 10 and then increases steadily and steeply with increasing volume of the material to be displaced. In this way, screwing in can be made noticeably easier for the user, for example in comparison to a trapezoidal edge body.With a trapezoidal edge body, the screw would initially have to cut not into an edge, but into a plateau surface of the trapezoidal edge body, so that a very large force would be required right from the start. In one embodiment, the inner lateral surface 5, viewed in cross-section, does not have a trapezoidal or trapezoidal contour for cutting an internal thread by a screw.

[0062] The invention provides at least three edges 6 that extend parallel to the central axis 7, project toward the central axis 7 when viewed in cross-section, and together form a smallest internal diameter of the screw channel 4, i.e., before a screw cuts an internal thread. This allows a screw that is screwed into the screw channel 4 to initially only touch the edges 6, i.e., not rest on a surface. The screw therefore initially only needs to be cut into edges 6, not into a flat surface, which would initially require greater force.

[0063] According to the invention, the metric or imperial screw 3 is made of a metal that has a higher hardness than aluminum. In particular, the screw 3 is made of steel, particularly preferably stainless steel.

Claims

1. Method for fixing a further component (2) to a component (1) by means of a metric or imperial screw (3) which is intended for screwing into a metric or imperial nut thread, respectively, wherein the screw (3) is made of a metal which has a higher hardness than aluminium, wherein the component (1) comprises a screw channel (4) which is limited in cross-section by an inner lateral surface (5), wherein the inner lateral surface (5) has an edge (6) which extends parallel to a central axis (7) of the screw channel (4) and projects towards the central axis (7) when viewed in cross-section, namely has the smallest distance to the central axis (7) of the entire inner lateral surface (5), wherein the central axis (7) extends perpendicular to the surface of the component (1) through which the screw (3) is screwed in, wherein the screw (3) is rotated in the direction of the central axis (7) into the screw channel (4) for fixing the two components (1, 2) and in this way produces an internal thread in the edge (6), wherein the component is produced from aluminium or fibre-reinforced plastic, wherein at least three edges (6) are provided which extend parallel to the central axis (7) and project towards the central axis (7) when viewed in cross-section.

2. Method according to the preceding claim, characterised in that a manual force is sufficient for screwing the screw (3) into the screw channel (4).

3. System comprising a component (1), a metric or imperial screw (3) which is intended for screwing into a metric or imperial nut thread, respectively, wherein the screw (3) is made of a metal which has a higher hardness than aluminium, and a further component (2), wherein the further component (2) is fixed to the component (1) by means of the screw (3), wherein the component (1) comprises a screw channel (4) for fixing by means of a screw (3), wherein the screw channel (4) is limited in cross-section by an inner lateral surface (5) and the inner lateral surface (5) has an edge (6) which extends parallel to a central axis (7) of the screw channel (4) and projects towards the central axis (7) when viewed in cross-section, namely has the smallest distance to the central axis (7) of the entire inner lateral surface (5), wherein the central axis (7) runs perpendicular to the surface of the component (1) through which the screw (3) is screwed, the system being such that the metric or imperial screw (3) for fixing the component (1) has been rotated in the direction of the central axis (7) into the screw channel (4) of the component (1) and in this way an internal thread has been produced in the edge (6), wherein the component is produced from aluminium or fibre-reinforced plastic, wherein at least three edges (6) are provided which extend parallel to the central axis (7) and project towards the central axis (7) when viewed in cross-section.

4. System according to the preceding claim, characterised in that the inner lateral surface (5) is closed in cross-section.

5. System according to one of the two preceding claims, characterised in that the screw channel (4) provides a free space (8) in cross-section on both sides of the edge (6), respectively.

6. System according to claim 3, characterised in that exactly four edges (6) or at most eight edges (6) are provided.

7. System according to the preceding claim, characterised in that the edges (6) are of identical construction, have an identical distance (11) from the central axis (7) and / or are arranged at preferably identical angular distances from one another around the central axis (7).

8. System according to one of the five preceding claims, characterised in that the entire inner lateral surface (5) is point-symmetrical to the central axis (7) when viewed in cross-section.

9. System according to one of the six preceding claims, characterised in that the edge (6) is formed by two flat surfaces (9, 10) which are angled towards each other, and which meet to form the edge (6).

10. System according to one of the seven preceding claims, characterised in that the component (1) was produced by extrusion.

11. System according to one of the eight preceding claims, characterised in that the distance (11) from the edge (6) to the central axis (7) is at least 70% and / or at most 95% of half the nominal external thread diameter (12) of the screw (3).

12. System according to one of the nine preceding claims, characterised in that the distance (11) from the edge (6) to the central axis (7) is at least 86% or at least 102% and / or at most 108% or at most 117% of the half external thread core diameter (13) of the screw (3).