Releasable joint for a steel shell of a swimming pool, steel sheet therefor, and method for the production thereof

Abstract

The invention relates to a releasable joint (1), in particular a joint (1) for a steel shell of a swimming pool, comprising a profile (2) having grooves (3) as well as two ends (4a, 5a) of metal sheet sections (4, 5), wherein the metal sheet sections each comprise protrusions (6, 7) in the region of the two ends (4a, 5a), which protrusions are accommodated in the grooves (3) in the profile (2). According to the invention, the profile (2) is formed in one piece, and the protrusions (6, 7) extend on both sides of the metal sheet sections (4, 5), and / or, in a top view of one of the metal sheet sections (4, 5), the protrusions (6, 7) taper toward one end (4a, 5a) of the metal sheet sections (4, 5). The invention also relates to a steel sheet for a swimming pool and to a method for the production thereof.

Description

[0001] Detachable connection for a steel shell of a swimming pool, steel sheet therefor and method for its production

[0002] The invention relates to a detachable connection, in particular a connection for a steel shell of a swimming pool, comprising a profile with grooves and two ends of sheet metal sections, wherein the sheet metal sections each have bulges in the region of the two ends, which are received in the grooves of the profile.

[0003] Furthermore, the invention relates to a steel sheet for a swimming pool.

[0004] Finally, the invention relates to a method for producing a steel sheet for a swimming pool, comprising providing a steel coil, straightening the steel coil, optionally introducing punched out portions for connections or the like, and cutting the steel coil to length in order to obtain a steel sheet for a steel shell of a swimming pool.

[0005] Swimming pools can be constructed in a variety of ways. In addition to very elaborate brick-built versions or those with stainless steel and / or glass elements, pools with a steel shell are particularly popular on the mainstream market. The steel shell itself is flexible and can be installed either in an excavated area and backfilled if necessary, or placed freely on a flat surface. The steel shell extends perpendicular to the floor and must be able to withstand the water pressure, especially near the bottom, when the pool is filled.

[0006] Steel shells are provided in the desired length for the construction of custom swimming pools and must be joined at the free steel sheet ends on site. For this purpose, the steel sheet ends were originally bolted together. The steel sheet ends were secured to one another in an overlapping manner using a large number of individual screw-nut combinations. Naturally, this requires a significant amount of manual labor. Furthermore, sufficient precision is required to ensure that the steel shell can withstand the high pressures generated by a filled swimming pool, particularly in the floor area. Subsequently, simpler solutions were developed that address the two aforementioned problems.In an initial solution currently in use, the two free ends of a steel sheet are bent twice, forming a bead across the entire width of each free end of the steel sheet. A strip with vertical grooves is provided to connect the two beaded steel sheet ends. The length of the strip corresponds to the width of the steel sheet or its height when erected. The two steel sheet ends can then be placed against each other, and the strip can be slid onto the steel sheet ends from above, so that the beads of the steel sheet ends are securely held in place by the strip.

[0007] The state-of-the-art solution with beaded ends on the steel sheets is an improvement over the screw-and-nut solution, as it allows for faster assembly and eliminates the high demands on manual precision work. A disadvantage, however, is that the process of producing the bead and folding it is very complex in two ways. Simply folding one end of the steel sheet is not sufficient because it can come loose due to the high water pressure. Therefore, at least two folds are necessary. Because the steel sheet must be of a certain thickness and the folding must occur across the entire width of the sheet, considerable force and complex machinery are required. The corresponding machines are not only expensive but can also hardly be integrated into another production process. It is therefore necessary to prepare the steel sheet separately in a dedicated machine.

[0008] DE 25 38 039 A1 discloses a solution for connecting steel sheet ends, according to which the steel sheet ends have bulges that are received in the grooves of a connector. For this purpose, double rows of bulges are provided at each steel sheet end, extending in the same direction, i.e., toward one side of the steel sheet. Roughly rectangular grooves of the connector, which is formed by a two-part retaining profile, are assigned to the two parallel bulge lines. The two parts of the retaining profile are held together by screws. Although this avoids the problem of laborious folding, this solution has not been adopted in practice. The reason for this is likely that the double row of punched-out sections makes fitting into the grooves relatively complex.For this purpose, the retaining profile is designed in two parts, so that the steel sheet ends can first be inserted into one half of the retaining profile, after which the second part of the retaining profile must be screwed on, which is relatively complex. Although, according to DE 25 38 039 A1, the screw connection of the retaining profile parts should only create a slight frictional connection, so that the actual tensile forces are absorbed by the bulges in the grooves, this does not change the fact that installation is complex. Another problem arises from the fact that under high tensile forces, the bulges can give way and peel off, causing one end of a steel sheet to be pulled out of the grooves.

[0009] This is where the invention comes in and the task is to further develop a detachable connection of the type mentioned at the beginning in such a way that simple assembly is possible and failure of the detachable connection during use is prevented as far as possible, even under high tensile forces.

[0010] A further aim of the invention is to provide a suitable steel sheet for a corresponding detachable connection.

[0011] Finally, a further aspect of the invention is to further develop a method of the type mentioned at the outset in such a way that a steel sheet can be provided with which it is possible to easily produce a detachable connection which can withstand high tensile forces.

[0012] The object of the invention is achieved if, in a detachable connection of the type mentioned at the outset, the profile is formed in one piece and the bulges extend to both sides of the sheet metal sections and / or the bulges are formed tapering towards one end of the sheet metal sections in a plan view of one of the sheet metal sections.

[0013] A detachable connection according to the invention of this type offers several advantages: Firstly, a one-piece profile is initially provided. This means that connecting the two ends of the sheet metal sections of a steel sheet does not require any further handling steps. The profile can, for example, be an extruded metal part. An extruded aluminum alloy is particularly suitable for this purpose. Assembly is also simplified in that, unlike in the prior art with steel sheets with bulges, one end does not first have to be inserted into one part of a holding profile before the second part of the holding profile is placed on top and fixed, but can be assembled by simply inserting it into a groove in the profile or sliding the profile on. Secondly, the bulges can extend on both sides of the sheet metal sections, which means that particularly high tensile forces can be absorbed.The first bulges ensure that the corresponding end of a section of steel sheet is held in the corresponding groove. The bulges on the opposite side of the sheet section prevent the sheet from peeling off and thus, up to a specified limit, reduce the sheet's ability to pull out of the groove. If the tensile forces on the first bulges, which provide anchoring, increase, the second, opposite bulges counteract this, so that extremely high tensile forces would be required to pull the end of a sheet section out of the profile.

[0014] It is also possible for the bulges to be designed so that they taper towards one end of the sheet metal section when viewed from above. In this case, it is not absolutely necessary for the bulges to extend on both sides of the sheet metal sections. Rather, it is sufficient if the bulges are only present on one side of the sheet metal sections. The bulges are preferably designed the same at both ends of the sheet metal. Contrary to expectations, it has been shown that particularly high tensile forces can be absorbed when the bulges taper towards one end when viewed from above. On the end face, i.e. on the side where the bulges act in the groove of the profile, the cross-section of a bulge is largest when viewed along the sheet metal surface. This cross-section tapers towards one end of the sheet metal section. This means that when tensile forces occur, a force can be absorbed effectively.

[0015] The inventive concept thus leads to simple assembly combined with high mechanical stability. The bulges on a top and bottom side can be arranged with gaps, so that as many bulges as possible are created along a line on both sides of the sheet. Preferably, the profile is designed to be elongated. As mentioned, the profile can be formed from an extruded alloy, in particular an aluminum alloy. This enables cost-effective production, although forming techniques other than extrusion are also conceivable. For example, the profile could be created by welding or by machining.

[0016] The profile is advantageously designed to be mirror-symmetrical in cross-section to a longitudinal axis, so that essentially corresponding or identical ends of sheet metal sections can be accommodated. The length of the profile preferably corresponds essentially to the length of the ends of the sheet metal sections, i.e., the width of a steel casing, so that good anchoring is ensured over the entire length of the sheet metal sections and high tensile forces can be absorbed over the entire length of a sheet metal section.

[0017] The grooves of the profile are preferably substantially rectangular. The profile can be formed with a top and a bottom, which are connected to each other by a central web. A side wall is provided on the sides, which, however, is interrupted and each provides a slot through which a sheet metal section emerges.

[0018] The profile advantageously has grooves with a projection against which first bulges come into contact, wherein the projection preferably runs perpendicular to the sheet metal sections. As a result, the first bulges come into contact perpendicular to the projection, so that these first bulges, which can also be regarded as claws, ensure a good anchoring effect and the absorption of high tensile forces. It is preferred that second bulges are provided on an opposite side of the sheet metal, which are less high than the first bulges. The height of the second bulges is advantageously designed such that it corresponds approximately to the height of the slot formed by the projection. As a result, a sheet metal section can lie in the groove and the first bulges then come into contact with the projection perpendicular to it.Due to the different heights of the first bulges and the second bulges, a sheet metal end cannot be inserted incorrectly into the profile, as the greater height of the first bulges does not allow insertion into the profile, which results in the sheet metal section extending out of the groove perpendicular to the longitudinal axis. Advantageous design variants provide for the first bulges to have a height that is at least 1.5 times, preferably at least 2.0 times, in particular 2.0 times to 3.0 times, the height of the second bulges. The first bulges should be designed as high as possible, within certain limits, to enable good claw engagement. The second bulges presumably provide counterpressure under high tensile forces, but can be designed with a lower height.However, it is also possible that the first bulges are the same height or less than the second bulges.

[0019] The first bulges and second bulges can be arranged so that they lie on a line. The line is usually a line parallel to the end of the respective steel sheet section. If the first bulges and the second bulges lie on a line, this means that at least part of the respective bulge touches the line or an area lies to the left and an area to the right of this line. When considering an imaginary line parallel to one end of the sheet section, the first bulges are advantageously located further from the end of the steel sheet section and the second bulges are closer to the end of the steel sheet section, although both the first bulges and the second bulges lie on a line that runs parallel to the end of the respective steel sheet section.

[0020] The bulges can be created in any way. Punching is preferred.

[0021] If the bulges are designed to taper towards one end of the sheet metal sections in a plan view of one of the sheet metal sections, it is sufficient, as mentioned, and also preferred for the bulges to be present on only one side of the sheet metal sections. In this case, the bulges can be approximately V-shaped in plan view, which benefits good force absorption. The bulges are preferably arranged in a single row. This row preferably extends parallel to one end of a sheet metal section. Thus, all of the bulges lie in a straight line. In this context, it is particularly preferred for the bulges to have a projecting nose on one contact side. The nose can encompass a highest point of the bulge. The projecting nose then lies against the profile in the groove.If tensile forces occur that lead to a deformation of the bulge, the nose bends upwards before the previously recessed areas of the bulge in the front area also come into contact with the contact side. This upward bending of the nose increases the height of the nose and prevents the steel sheet from slipping even when there are no counter-embossings, i.e. the bulges are only on one side of the sheet. In other words: the special design of a bulge with a nose ensures that the sheet is held securely even under high tensile forces when there are no counter-embossings. This is achieved because there is a pressure point at a distance from the slot in the groove, which prevents the steel sheet from slipping. In a plan view, the front edge of the bulges, which are preferably identical in design, has a w-shape.The bulges can be located directly at one end of the sheet metal sections, with the ends being bulged. This means that one end of the sheet metal section is part of a bulge. This end of the sheet metal section then deviates from a straight line, corresponding to the profile of the bulges.

[0022] The further object of the invention is achieved if, in a steel sheet of the type mentioned at the outset, the bulges extend on both sides of the steel sheet and / or the bulges are designed to taper towards the ends of the sheet sections in a plan view of sheet sections of the steel sheet with two ends of the sheet sections.

[0023] As previously explained, this provides the advantage that, with a one-piece profile, the respective steel sheet ends can be easily assembled by simply sliding the profile in or out. At the same time, this ensures good anchoring and high tensile load capacity. Peeling of individual protrusions is prevented up to extremely high tensile forces, as the alternately arranged protrusions ensure both a secure grip and prevent peeling. The latter also applies, as explained above, when the protrusions, viewed from above, are designed to taper towards the ends of the sheet sections with two ends of the sheet sections.

[0024] It can be provided that there are first bulges on a first side of the sheet and second bulges on an opposite side of the sheet, the second bulges having a lower height than the first bulges. The first bulges ensure that the steel sheet is clamped, while the second bulges effectively counteract possible peeling due to high tensile forces. It can be provided that the first bulges have a height which is at least 1.5 times, preferably 2.0 times, in particular 2.0 times to 3.0 times, the third height of the second bulges. As explained above, a coordinated height of the individual bulges can provide an optimized result in terms of absorbing high tensile forces without the risk of detachment.

[0025] The bulges can be designed to taper towards one end of the sheet metal sections in a plan view of one of the sheet metal sections and can be present only on one side of the sheet metal sections. The tensile forces that occur can then be absorbed particularly well. In this regard, tensile forces of approximately 60 kg / cm are specified based on a round pool diameter of 8.1 m and a water height of 1.5 m (the disclosure includes any pool shape and is not limited to round pools). With appropriate design, these values ​​can be far exceeded. It can also be provided that the bulges are designed to be approximately V-shaped in plan view. The bulges can be arranged in a single row. The bulges preferably have a projecting nose on one side of the system.The nose can enclose one of the highest points of the bulge, which has the advantage of high force introduction when tensile forces occur, because the nose can deform until the front edge of a bulge essentially comes into complete contact with the groove. Tensile tests have shown that a series of bulges tear out completely, but not individual bulges. This shows that the bulges can absorb such high forces that material failure occurs in other areas if the tensile forces become too high. If a protruding nose and one-sided bulges are planned, the punching edge for the nose should run on the left in the longitudinal direction of the bulge and on the right in the direction of sheet tension. This can prevent material tearing perpendicular to the tensile direction.

[0026] The bulges can be located directly at one end of the sheet metal sections, with the ends optionally being bulged. The bulges thus extend into the end of the sheet metal sections.

[0027] If bulges are provided on only one side of the sheet metal sections and these bulges taper towards one end of the sheet metal sections, for example in a V-shape, it is particularly preferred that the bulges are arranged relatively close to one another and advantageously have a certain length. Advantageously, a ratio of a width of a bulge in the front-side, widest region to a distance between two adjacent bulges is 1.5 to 2.5, preferably 1.75 to 2.25. A ratio of the width of a bulge in the front-side, widest region to a length is preferably 0.5 to 0.8, particularly preferably 0.6 to 0.75. A ratio of a front-side height of a bulge to a length of the bulge is preferably in the range from 0.25 to 0.75, in particular 0.3 to 0.65.

[0028] Typical sheet thicknesses range from 0.3 mm to 1 mm. A typical sheet thickness is 0.5 mm to 0.7 mm.

[0029] The further object of the invention is achieved by a method of the type mentioned at the outset, wherein bulges are provided in the region of the ends of the steel sheet, which bulges extend to both sides of the sheet sections.

[0030] A particular advantage achieved with a method according to the invention is that a method according to the invention can be easily implemented with existing systems through minor adaptation. While with conventional single or multiple bending of a steel sheet end, the steel sheet to be processed either has to be removed and folded separately on another system or, alternatively, the system is designed to be correspondingly long, which leads to high system costs, the introduction of bulges can be easily integrated into a conventional process or into a processing system. All that is required for this is a punch and a corresponding die so that the bulges can be introduced at a suitable location, in particular by punching. This allows the production of an optimal steel sheet with a suitable profile that can absorb high tensile forces.

[0031] Further features, advantages, and effects of the invention will become apparent from the exemplary embodiment presented below. Reference is made to the drawings, which show: Fig. 1 shows a one-piece profile;

[0032] Fig. 2 a top view of a steel sheet end;

[0033] Fig. 3 a plan view of the underside of a steel sheet end;

[0034] Fig. 4 Ends of a steel sheet in a side view;

[0035] Fig. 5 shows a detachable connection between a profile according to Fig. 1 and a steel sheet according to Fig. 4;

[0036] Fig. 6 a profile with one end of an inserted sheet metal section;

[0037] Fig. 7 is a plan view of one end of a sheet metal section with bulges;

[0038] Fig. 8 is a front view of the sheet metal section in Fig. 7.

[0039] Fig. 1 shows a profile 2. The profile 2 is usually made of a metal or an alloy such as an aluminum alloy, although plastics or composite materials such as fiber-reinforced plastics can also be used. The decisive factor is that the profile 2 can withstand sufficiently high forces. The profile 2 is preferably produced by extrusion or extrusion. This makes it easy to achieve a one-piece design of the profile 2 with grooves 3. The grooves 3 are formed by a projection 3a of the profile 2 and sections 3b, 3c, 3d. The profile 2 is designed symmetrically to a longitudinal axis X of the profile 2, with the profile 2 running longitudinally along the longitudinal axis X. The two grooves 3 have essentially the same size in cross-section to the longitudinal axis X.The projections 3a, which are arranged on both sides of a mirror symmetry plane running through the section 3c, extend essentially parallel to the longitudinal axis. The projections 3a end before the section 3d, so that slots 3e are formed. Fig. 2 to Fig. 4 show sections of a steel sheet which are representative of end sheet sections 4, 5 of a steel sheet. As can be seen in the views according to Fig. 2 and Fig. 3, the corresponding sheet sections 4, 5 have first bulges 6 and second bulges 7. These bulges 6, 7 extend in the direction of a first sheet side 61 and a second sheet side 71. The first bulges 6, which are particularly visible in the side view in Fig. 4, are formed with a greater height than the second bulges 7, which are also particularly visible in Fig. 3.A height of the first bulges 6 can, for example, be 2.0 times that of the second bulges 7.

[0040] As can be seen from the combined view of Fig. 2 to Fig. 4, the bulges 6, 7 are arranged such that they lie on a common line. In the exemplary embodiment, this line is parallel to a first end 4a of a first sheet metal section. The same applies to a second end 5a of a second sheet metal section. However, a maximum elevation of the first bulges 6 is further away from an end 4a of the associated sheet metal section 4 than a maximum elevation of the second bulges 7 is from an end 5a of the associated sheet metal section 5.

[0041] Fig. 5 shows a detachable connection 1. The detachable connection 1 comprises the profile 2 as well as a sheet metal section 4 and a sheet metal section 5, which are inserted into the corresponding groove 3 of the profile 2 in the region of the first end 4a and the second end 5b. The sheet metal sections 4, 5 are an integral part of a steel casing and represent its ends. The sheet metal sections 4, 5 have the recesses 6, 7 as previously explained. Approximately two bulges 6 per centimeter are provided. The bulges 6 are arranged in alternation with bulges 7, so that these are also equidistantly spaced.

[0042] The first protrusions 6 can be designed such that they are arranged with one end face exactly along a plane that runs transversely to the steel sheet. This also applies to the second protrusions 7. In both cases, the protrusions 6, 7 can each be arranged equidistantly.

[0043] The two sheet metal sections 4, 5 can be easily inserted into the profile 2, or the profile 2 can be pushed onto the ends 4a, 5a of the sheet metal sections to form the detachable connection 1. On a construction site, sheet metal sections 4, 5 can be placed against one another, after which the profile 2 is pushed out. This easily creates the detachable connection 1. The provided bulges 6, 7 can absorb high tensile forces without worrying that the first bulges 6 will peel off and subsequently the steel sheet will slide out of the grooves 3. A detachable connection 1 according to the invention thus enables simple assembly of a highly resilient structure.

[0044] 6 to 8 show a further variant of a detachable connection 1 according to the invention, which is particularly preferred. In this variant, the detachable connection 1 is designed such that the bulges 6 extend only to one side of the sheet metal sections 4, 5. The bulges 6 are shaped such that they taper towards an end 4a of a sheet metal section 4, as can be seen in Fig. 7. In the plan view according to Fig. 7, the bulges 6 have an approximately V-shaped profile. The bulges 6 encompass the end 4a, so that the end 4a is also bulged, as can be seen in Fig. 8; however, a bulge 6 at the end 4a is not mandatory, and the bulge 6 can already merge into a flat sheet metal area before the end 4a. In the widest area on the front side, the bulges 6 have a projecting nose 8, which rests in the groove 3 on the front side.If no tensile forces are present, only the nose 8, which also includes a highest point of the associated bulge 6, rests against an inner side of the area 3a of the groove 3. This results in the formation of an end region of the bulge 6 with a substantially w-shape, as shown in Fig. 7. This has the advantage that bulges 6, 7 on the opposite side, which primarily serve not to absorb a tensile force but to prevent the sheet from slipping under high tensile forces, can be omitted. If high tensile forces occur, the nose 8 initially deforms upwards, thus towards the area 3b, before the remaining edge regions of the end region of the bulge 6 come into contact with the inner side of the section 3a. Once this state is reached, the end face of the bulge 6 in the edge region rests essentially completely against the inner side of the section 3a.Due to the raised shape of the bulge 6, slippage of the steel sheet is no longer possible. To allow for appropriate expansion, a clearance is provided between the apex of the bulge 6 and section 3b. Clearance is also provided in the direction of section 3c so that the steel sheet can be loosened by light tapping and appropriate movement and / or easily shifted within profile 2, if necessary.

[0045] Tests for the two-sided and one-sided variants of a detachable connection 1 have shown that both variants are capable of absorbing such high forces that a specified minimum tensile load is easily achieved. In terms of ease of production, the one-sided variant shown in Figs. 6 to 8 is particularly preferred.

Claims

Patent claims 1. Detachable connection (1), in particular a connection (1) for a steel shell of a swimming pool, comprising a profile (2) with grooves (3) and two ends (4a, 5a) of sheet metal sections (4, 5), wherein the sheet metal sections (4, 5) in the region of the two ends (4a, 5a) each have bulges (6, 7) which are received in the grooves (3) of the profile (2), characterized in that the profile (2) is formed in one piece and the bulges (6, 7) extend on both sides of the sheet metal sections (4, 5) and / or the bulges (6, 7) are formed so as to taper towards one end (4a, 5a) of the sheet metal sections (4, 5) in a plan view of one of the sheet metal sections (4, 5).

2. Detachable connection (1) according to claim 1, characterized in that the profile (2) is designed to be longitudinally extended.

3. Detachable connection (1) according to claim 1 or 2, characterized in that the profile (2) is mirror-symmetrical in cross section to a longitudinal axis (X).

4. Detachable connection (1) according to one of claims 1 to 3, characterized in that a length of the profile (2) substantially corresponds to a length of the ends (4a, 5a) of the sheet metal sections (4, 5).

5. Detachable connection (1) according to one of claims 1 to 4, characterized in that the profile (2) has grooves (3) with a projection (3a) against which first bulges (6) come into contact, wherein the projection (3a) preferably runs perpendicular to the sheet metal sections (4, 5).

6. Detachable connection (1) according to claim 5, characterized in that on an opposite sheet metal side (71) second bulges (7) are provided, which have a lower height than the first bulges (6).

7. Detachable connection (1) according to claim 6, characterized in that the first bulges (6) have a height which is at least 1.5 times, preferably at least 2.0 times, in particular 2.0 times to 3.0 times, the height of the second bulges (7).

8. Detachable connection (1) according to one of claims 1 to 7, characterized in that the bulges (6, 7) are punched.

9. Detachable connection (1) according to one of claims 1 to 5 or 8, characterized in that the bulges (6, 7) in plan view of one of the sheet metal sections (4, 5) are designed to taper towards one end (4a, 5a) of the sheet metal sections (4, 5) and are present only on one side of the sheet metal sections (4, 5).

10. Detachable connection (1) according to claim 9, characterized in that the bulges (6, 7) are approximately V-shaped in plan view.

11. Detachable connection (1) according to claim 9 or 10, characterized in that the bulges (6, 7) are arranged in a single row.

12. Detachable connection (1) according to one of claims 9 to 11, characterized in that the bulges (6, 7) have a projecting nose (8) on one contact side.

13. Detachable connection (1) according to claim 12, characterized in that the nose (8) comprises a highest point of the bulge (6, 7).

14. Detachable connection (1) according to one of claims 9 to 13, characterized in that the bulges (6, 7) are arranged directly at one end (4a, 5a) of the sheet metal sections (4, 5) and the ends (4a, 5a) are optionally bulged.

15. Steel sheet for a swimming pool, wherein the steel sheet has bulges (6, 7) at its ends which can be received in grooves (3) of a profile (2) in order to form a steel casing, characterized in that the bulges (6, 7) extend on both sides of the steel sheet and / or the bulges (6, 7) in plan view of sheet sections (4, 5) of the steel sheet with two ends (4a, 5a) of the sheet sections (4, 5) are designed to taper towards the ends (4a, 5a) of the sheet sections (4, 5).

16. Steel sheet according to claim 15, characterized in that first bulges (6) are present on a first sheet side (61) and second bulges (7) are present on an opposite sheet side (71), the second bulges (7) having a lower height than the first bulges (6).

17. Steel sheet according to claim 16, characterized in that the first bulges (6) have a height which is at least 1.5 times, preferably at least 2.0 times, in particular 2.0 times to 3.0 times, the height of the second bulges (7).

18. Steel sheet according to claim 15, characterized in that the bulges (6, 7) in plan view of one of the sheet sections (4, 5) are designed to taper towards one end (4a, 5a) of the sheet sections (4, 5) and are present only on one side of the sheet sections (4, 5).

19. Steel sheet according to claim 18, characterized in that the bulges (6, 7) are approximately V-shaped in plan view.

20. Steel sheet according to claim 18 or 19, characterized in that the bulges (6, 7) are arranged in a single row.

21. Steel sheet according to one of claims 18 to 20, characterized in that the bulges (6, 7) have a projecting nose (8) on one contact side.

22. Steel sheet according to one of claims 18 to 21, characterized in that the nose (8) comprises a highest point of the bulge (6, 7).

23. Steel sheet according to one of claims 18 to 22, characterized in that the bulges (6, 7) are arranged directly at one end (4a, 5a) of the sheet sections (4, 5) and the ends (4a, 5a) are bulged.

24. A method for producing a steel sheet for a swimming pool, in particular a steel sheet according to one of claims 15 to 23, comprising providing a steel coil, straightening the steel coil, optionally introducing Punching out for connections or the like, and cutting the steel coil to length in order to obtain a steel sheet for a steel shell of a swimming pool, characterized in that in the region of ends (4a, 5a) of the steel sheet, bulges (6, 7) are introduced which extend to one or both sides of the sheet sections (4, 5).

25. Method according to claim 24, characterized in that the bulges (6, 7) are introduced by punching with a punch and an opposite die.

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