WO2012152287A2

WO2012152287A2 - Platform construction

Info

Publication number: WO2012152287A2
Application number: PCT/DK2012/050162
Authority: WO
Inventors: Aage STARUP
Original assignee: Invenstar Aps
Priority date: 2011-05-12
Filing date: 2012-05-11
Publication date: 2012-11-15
Also published as: EP2715015A2; WO2012152287A3

Abstract

Platform construction suitable to be arranged inside a tower structure or outside a building structure, where said platform construction comprises a plurality of cooperating components: - a first plurality of cover elements, where each cover element has two parallel side edges extending, in use, downwards from a load carrying surface, where means are provided along the side edges for connecting adjacent covering elements side edge to side edge; - a second plurality of primary beams - a third plurality of secondary beams where the side edges of the cover elements are differently shaped, where a first side edge has a first section extending substantially vertically downwards from the horizon¬ tally arranged load bearing surface, where a distal end of the first section is shaped into a U-shaped second section, such that the free end of the first edge is pointing substantially upwards, and where the distance from the bottom of the U to the load bearing surface is "a"; and where a second side edge extends substantially vertically down the length "a" such that when the second side edges free end, of an adjacent cover element is inserted into the U, the load-bearing surfaces of the adjacent cover elements will be in one plane, where the secondary beams has an upper and lower portion connected by a web, where the upper portion is provided with a cavity along at least a substantial part of its length, such that the connected side edges of two adjacent cover elements fits snugly inside the cavity with limited play, and where the primary beams comprises an upper part and a lower part, and a web body connecting said upper and lower parts, where the secondary beams are connected either to the web body or to the lower part of the primary beams, such that an upper surface of the upper part is supporting the cover elements.

Description

Platform construction

Field of the Invention

The present invention relates to a platform construction suitable to be arranged inside a tower structure or outside on a building structure. Furthermore, the invention is also directed at a tower structure including such a platform.

Background of the Invention

In the art it is known to provide platforms inside tower structures, for example inside the tower structure of a wind turbine tower. An example of such an arrangement is illustrated in US 2010 122508, wherein a number of platforms are suspended inside the tower structure. The platforms serve to allow workers to carry out maintenance and inspection at different levels inside the tower structure. Furthermore, the platform's function is to stabilize internal structures such as for example elevators and the like, such that even for relatively tall towers good support is provided for the rails of the elevators. Also in towers where ladders or other types of steps are used it is often not practical to have one long ladder spanning from the bottom of the tower to the top of the tower and as such platforms are introduced along the way in order to be able to use ladders/steps of a limited height. The inventive platform according to the present invention may also be used externally on buildings as for example balconies and the like. In addition, the inventive platform system may be used as platform sections for example in the wind turbine nacelles. Object of the Invention

The object of the invention is to provide a platform assembled from components where it is relatively easy to fit the components such that platforms of any size may be assembled and still maintain their rigidity, structure and strength.

Preferably, the platforms should be lightweight to ease the assembling and installation, to be able to pack in kits, to make transport more safe and cost effective, to reduce overall costs and to use the suspension cables or stays from which the platforms normally are suspended/fastened. Description of the Invention

The invention addresses this by providing a platform which is particular in that the platform construction is suitable to be arranged inside a tower structure or outside a building structure, where said platform construction comprises a plurality of cooperating components:

- a first plurality of cover elements, where each cover element has two parallel side edges extending, in use, downwards from a load carrying surface, where means are provided along the side edges for connecting adjacent covering elements side edge to side edge;

- a second plurality of primary beams

- a third plurality of secondary beams

where the side edges of the cover elements are differently shaped, where a first side edge has a first section extending substantially vertically downwards from the horizontally arranged load bearing surface, where a distal end of the first section is shaped into a U-shaped second section, such that the free end of the first edge is pointing substan- tially upwards, and where the distance from the bottom of the U to the load bearing surface is "a"; and where a second side edge extends substantially vertically down the length "a" such that when the second side edge's free end of an adjacent cover element is inserted into the U, the load-bearing surfaces of the adjacent cover elements will be in one plane,

where the secondary beams have an upper and lower portion connected by a web, where the upper portion is provided with a cavity along at least a substantial part of its length, such that the connected side edges of two adjacent cover elements fits snugly inside the cavity with limited play, and

where the primary beams comprise an upper part and a lower part, and a web body connecting said upper and lower parts, where the secondary beams are connected ei- ther to the web body or to the lower part of the primary beams, such that an upper surface of the upper part is supporting the cover elements.

The plurality of cooperating components does as will be explained assemble to become a strong rigid and light platform construction due to the inventive properties of the single elements.

Firstly, the cover elements are shaped with a load carrying surface from which surface two side edges extend downwards in the use situation. The side edges are provided with different shapes such that it is possible to interfit one type of side edge inside the other side edge, whereby the load carrying surface of the two adjacent cover elements will be in the same plane by constituting a substantially homogenous surface and at the same time due to the shape of the side edges they are mutually interlocked thereby creating a very stable connection. The U-shape of the first side edge provides resistance such that it is not possible to bend adjacent cover elements along the side edges in an outward direction. To resist the downward bending the secondary beam member is provided with a cavity in an upper part, such that the connected side edges snugly fit inside the cavity in the upper part of the secondary beam. The cavity thereby locks the two different side edges together and at the same time supports the side edges in such a manner that it is not possible to bend the connection between two adjacent cover ele- ments in a downwards direction.

In a preferred embodiment which will be explained below the cavity is provided with a special shape corresponding to the outside shape of the side edges. In this embodiment it is foreseen that the secondary beam is slid over and along the connected side edges in order to create the locking characteristics of the upper part of the secondary beam. The primary beams are designed with a somewhat larger cross section such that the moment of inertia will be larger than what is the case for the secondary beams. The primary beams therefore will be the main load carrying structure. By connecting the secondary beams to the primary beams by means of a rigid and strong connection the loads from the platform are effectively transferred to the load bearing structure. Furthermore, as the secondary beams are usually smaller than the primary beams, it is possible to fit the secondary beams inside the cross section, i.e. along the web of the primary beams which in turn provides for a very strong and rigid connection.

In a further advantageous embodiment of the invention the first side edge's first section is provided with a convex section or a concave section at a predetermined distance from the load carrying surface, and where the second side edge has an opposite fitting shape at the same predetermined distance from the load carrying surface, where these sections are provided on the side of the side edge facing away from the opposite side edge, whereby when the second side edge is positioned in engagement with the first side edge of an adjacent cover element, the concave and convex sections of the two side edges will mate.

In the context of this application at least the word convex means curving out or bulging outward, as opposed to concave, which is to be understood as curving or bulging inwards. The concave and convex sections serve to create an even better lock such that when the second side edge is inserted in the U-shape and tilted into correct position whereby the load carrying surfaces on the connected cover elements are flush, the convex/concave sections will further improve the vertical lock between two adjacent elements. Whether it is the first side edge which is provided with the convex section or the concave section has no influence on the workings of the resulting lock and as such any side edge may be provided with one or the other part if one is provided with a convex section the other side edge shall be provided with the concave section. In a still further advantageous embodiment the first side edge's first section is provided with a flange extending substantially perpendicularly away from the first section at a predetermined distance from the load carrying surface, and where the second side edge also has a flange extending substantially perpendicularly away from the first section at a predetermined distance from the load carrying surface, and where these flanges are provided on the side of the side edge facing the opposite side edge, and where the cavity in the secondary beam has longitudinal slits for accommodating said flanges when the side edges are placed in the cavity provided in the upper part of the secondary beams.

The flanges also serve to secure the cover elements relative to each other, but also as they are provided on each side edge facing the opposite side edge they will when the connection between two adjacent cover elements is inserted into the cavity in the upper part of the secondary beam where the cavity is provided with slits corresponding to the flanges, further stabilize and secure the connection between two adjacent cover elements and the secondary beam's upper part. In this context it shall be noted that the cross sectional shape of the flange is not that important, but it is clear that the more square or rectangular the flange is relative to the side edge, the better grip it will have in the upper section of the secondary beam's cavity thereby creating better interlocking properties between the cover elements and the secondary beam and thereby increase the stability of the platform structure as such.

In a still further advantageous embodiment the means provided for connecting the secondary beams to the primary beams is a plate member arranged perpendicularly to the ends of the secondary beams, where said plate is provided with apertures, and the web of the primary beam is provided with corresponding apertures, such that a mechanical connection by means of bolts and nuts is provided, between the web of the primary beams and the plates of the secondary beams. Although this is a relatively simple and well-known method of connecting elements in a metal structure, it is particularly useful in this connection in that it gives a very stiff, rigid, strong and very easy-to-assemble connection such that the stiffness already provided by the side edges of the cover elements and the inventive cavity in the upper part of the secondary beam is transferred to the primary beams maintaining the overall stability, integrity and rigidity of the platform structure. Depending on the materials used for building the platform, the bolts may naturally be replaced by weldings or rivets which naturally fall within the choice of the skilled person.

The plate member arranged substantially perpendicularly to the secondary beams may be a separate plate welded to the end of the beam, or may be an end section of the beam, typically only the web portion of the beam, which has been bend into an angle of approx. 90 ⁰ relative to the rest of the web.

In a further advantageous embodiment of the invention a bracket is provided for connecting secondary beams to primary beams, where said bracket has a generally omega- shape, including two flat flanges extending away from a bent section, where the bent section is shaped to conform to a part of the cross section of the primary beams.

In use the flat flanges of the bracket is fastened to what in use will be an underside of the secondary beams, where the bent section will fit snugly over/around part of the primary beam. When the platform is loaded, and deformed, i.e. the primary beams bends downwards, the bracket connection will cause the secondary beams to be activated, and thereby also the connection to the primary cover elements. In this manner the bracket(s) will activate the entire construction, and any load will be distributed throughout the construction, whereby the load bearing capabilities of all elements are utilised.

In a still further advantageous embodiment of the invention an edge beam is provided, where said edge beam is arranged along the periphery of the platform, and where first and secondary beams are connected to said edge beam, where the edge beam optionally may extend above the load carrying surface of the platform, or be arranged under the load carrying surface. Along the periphery of the platform, whether it is installed inside a tower structure or attached to a building as for example a balcony, it will provide extra stability when an edge beam is provided along the periphery. Typically, for platforms installed inside towers the platform will have a substantially circular shape, and as such the edge beam will also be circular. The secondary and primary beams are connected to the edge beam for example by the same means as described above with respect to how the secondary beam is connected to the primary beam, i.e. using a bolt connection and a connection plate and as such the edge beam will become an integrated part of the overall platform construction. The ends of the cover elements otherwise not being supported will be provided with the added support from the edge beam. In this context it should be noted that for some applications the rigid connections between adjacent cover elements as explained above are sufficient in order to provide the stability and support which is required by a platform of this type, but naturally the edge beam further increases the strength and integrity of the platform.

In a further advantageous and preferred embodiment of the invention the cover elements, the primary beams and/or the secondary beams are extruded, where the material is aluminium or a metallic alloy.

Overall, it is preferred to manufacture the platform from extruded aluminium. Aluminium has a lot of good material characteristics, it is easy to shape during the extrusion process such that the relatively advanced cross sections being used with the present invention may easily and relatively cheaply be obtained in that it is a question of design- ing the die used in the extrusion process to the desired shape.

Furthermore, aluminium is extremely strong and as aluminium has been a major part behind the thinking and development of the inventive platform according to the invention, all components of the platform are designed as elements having a substantially constant cross section facilitating the extrusion process. Only minor parts, need to be worked in order to fit that particular part into the platform construction.

In a further advantageous embodiment of the invention the cover elements, the primary beams, and/or the secondary beams are extruded or pulltruded, where the materials is selected from glass-, carbon or steel reinforced resin based materials.

Although especially for platforms to be built into tower constructions as is the case with wind turbine towers and for most balconies, it is desirable to make them from a non-corrosive aluminium extrusion process as described above, it is also possible to manufacture the different parts of the platform from resin-based materials. The advantage of using resin-based materials is that they are very light, very strong and may be easily reworked to fit into desired constructions. Furthermore, resin-based materials are non-corrosive and resistant to most chemicals and as such may be used in a wide variety of environments where otherwise metallic-based alloys would be exposed to corrosion.

In a still further advantageous embodiment the materials may be combined such that some of the elements or beams are made from one type of material and other elements or beams from a different material. This is particularly interesting in order to address various issues as weight, rigidity, corrosion, electric conductivity etc.

It is also contemplated to combine materials, i.e. the sub-structures first and second beams may be made from aluminium, whereas the rest may be made from steel or plas- tics. The platforms working surface may also be grates fitted onto the carrying structure where desired.

In a still further advantageous embodiment means for suspending the platform are provided, where said means comprises suspension beams connected to the primary beams, where said suspension beams comprise attachment brackets suitable to be connected to suspension wires, stays or the like. Although the platform may be attached with brackets directly to for example a building structure or the inside wall of a tower structure, it is also possible as was mentioned in the prior art document US 2010 0122508 to suspend the platform in wires, stays or the like as is customary in the art.

The invention is also directed at a tower structure incorporating a platform having the inventive features as mentioned above.

Due to the platforms ability to be assembled inside of for example a tower it is also possible to replace older platforms with the inventive lighter and stronger platform without having to dismantle the tower. Also as some wind turbine manufactures have standard tower structures, the platform is easily adaptable, due to the use of extruded profiles cut to specific lengths, having the interlocking features, whereby platform dimensions can be adapted to the specific tower and assembled in situ.

Description of the Drawing

The invention will now be elaborated with reference to the accompanying figures wherein figure 1 illustrates a platform according to the invention

figure 2 illustrates a side view of the platform

figure 3 illustrates the platform seen from below

figure 4 illustrates a detail of the construction

figure 5 illustrates a covering element

figure 6 illustrates a cross-sectional view of a secondary beam

figure 7 illustrates a cross section through a primary beam

figure 8a illustrates the platform provided with cover elements supported by first and secondary beams

figure 8b illustrates an alternative embodiment where the edge beam is provided outside the distal ends of the primary and secondary beams.

Figure 9 illustrates assembly between primary and secondary beams.

Detailed Description of the Invention

In figure 1 is illustrated a platform 1 according to the invention. Basically, the inventive platform 1 according to the invention is made from the assembly of the three profiles as illustrated in figures 5, 6 and 7 as will be explained below.

The platform in the detailed embodiment is described with respect to a platform suitable to be arranged inside a hollow tower structure, such as for example inside towers for wind turbines and the like. The platforms serve a number of purposes as already elaborated upon. It is therefore important that the platform is strong, rigid and provides a substantially flush surface such that personnel working or travelling on the platform do not experience any inconvenience from the platform itself. In this embodiment the platform is suspended by means of stays 10 arranged in mounting brackets 11 substantially evenly spaced along the periphery of the platform 1. Further details of the mounting bracket will be discussed with reference to figure 4 below. The load carrying surface 2 of the platform 1 is made from a plurality of covering elements 3 which all have substantially the same cross-sectional shape, and in this embodiment are made from an extruded aluminium profile which is cut to size. Therefore, all the covering elements 3 have identical cross-sections as is illustrated in figure 5. However, the platform may be designed using two or more cross section areas across the platform covering elements to make use of the benefits of large extruding mould techniques. It is especially beneficial for the middle sections where the waste from circular shape is less than at the sides.

The particular platform illustrated in figure 1 is provided with openings 12, 13 in the platform. The opening 12 is provided such that a ladder or steps may be inserted whereby it becomes possible for personnel wanting to ascend or descend the tower, to move from one platform to the next, and the opening 13 is provided in order to allow an elevator/lift to travel through the platform in order to bring personnel or goods from the bottom of the tower to the top of the tower.

Naturally, platforms without openings or with other designs of the openings to accommodate other items may be provided with the inventive system.

Along the periphery of the platform 1 is provided an edge beam 40. Naturally, where the openings 12, 13 are provided special reinforcements corresponding to the edge beam must be provided.

Turning to figure 2 a side view of the platform is illustrated from which it is evident that a very shallow and light construction is provided with the inventive system.

Turning to figure 3 the platform is seen from below, i.e. upside down. In this view the primary beams 30 as well as the secondary beams 20 are easily detected. In its essence the system is made up of the three parts illustrated in figures 5, 6 and 7 which are evident from the illustration depicted in figure 3.

The main beams 30 provide the main structural stability and strength whereas the sec- ondary beams assist in this structure as well as maintain the cover elements 3 in fixed relationship to the carrying structure constituted by the primary and secondary beams 20, 30.

The edge beam 40 is attached to the free ends 20', 30' of the first and second beams 20, 30 such that the edge beam 40 supports the integrity of the entire structure. In this embodiment the edge beam 40 is attached to the first and secondary beams 20, 30 by flange plates and bolts such that a mechanically stable and strong connection is created.

The bolts 41 are of course dimensioned to the task, but may also be replaced by other fastening means depending on the materials in use, for example when using aluminium or other metals it is possible to weld the various elements of the invention together in a strong and rigid connection.

In this connection it should be noted that especially for tower structures it is an impor- tant aspect of the invention that it may be assembled from parts inside the tower structure, and as such it is not necessary to have an opening in the tower structure large enough to allow the assembled platform to be introduced inside the structure, but as long as the separate parts making up the platform can be introduced, it is possible to assemble a platform according to the present invention. Furthermore, as the principles of assembly as will be explained below are relatively simple, it is limited task to assemble the platform inside the tower structure once the parts have been provided in the correct sizes and amounts.

This aspect is also interesting for platforms used as balconies, in that transport from the workshop to the place of installation is relatively easier and cheaper with disassembled parts which may be transported by ordinary road transport, whereas larger assembled platforms/constructions requires special transport and permits - and thus added expense. With reference to figure 4 a detail of the construction is illustrated. In this view the edge beam 40 has been removed in order to illustrate the connections. As is evident the wire or stay 10 is connected to a mounting bracket 11 which is passed through an aperture in a covering element 3 such that the mounting bracket by means of a plate 14 is connected by means of bolts to the main beam 30. A secondary beam 20 is likewise connected to the web.31 of the main beam by means of bolts. A further stabilizing holder 15 is provided between the secondary beam 20 and the plate 14 such that a relatively strong boxlike structure is created for the mounting bracket 11 in order to transfer the load from the platform in use to the stays 10.

The secondary beam is illustrated in a cross-sectional view in figure 6. The secondary beam 20 comprises an upper portion 21, a lower portion 22 and the web 23 connecting the upper portion 21 with the lower portion 22. In the upper portion 21 is provided a cavity 24 upwardly open such that the side edges of the covering element 3 when assembled as will be explained below may be fastened/locked due to the geometry of the cavity 24.

The platform may be partly suspended or fastened using customer designed/required structures/details/items integrated in the platform for example plates or brackets used for passage or fixation of elevators, ladders and cables. This suspension may then be an integrated part of the individual platform structure.

The covering element 3 illustrated in figure 5 comprises a load carrying surface 4 and extending downwardly from the load-carrying surface 4 is first and second side edges 5, 6. The first side edge in this embodiment comprises a first vertical part 50 which at the lower end is shaped as a U, 51. The distance from the load carrying surface 4 to the bottom of the U is set at " A" .

The second side edge 6 substantially extends vertically downwards as well such that the distal end 60 of the second side edge 6 is a distance "A" from the load carrying surface 4. The distal end 60 is dimensioned such that it will fit inside the U, 51 of the first side edge 5.

Furthermore, the first side edge 5 is provided with a convex section 52 which in size corresponds to a concave section 61 provided on the second side section 6. As adjacent cover elements 3 are connected by inserting the distal end 60 of the second side edge 6 into the U-shape 51 of the first side edge 5, the concave section 61 will snugly fit into the convex section 52 such that a very close connection is created by the special shape of the side edges. Furthermore, as the distance from the load-carrying surface 4 to the bottom of the U is "A", and the second side edge 6 has the same distance between the load-carrying surface 4 and the distal end 60, the load-carrying surfaces of two adjacent cover elements 3 will be substantially flush.

The convex and concave sections 52, 61 provide a vertical lock such that once two cover elements are assembled as described above, the concave/convex connection will not allow one cover element to move vertically with respect to the other element due to the interlocking by the sections 52, 61.

On the opposite side of both side edges 5, 6 is provided a flange 53, 62. The flanges 53, 62 fit into corresponding slits 53', 62' such that when the components are assembled, i.e. when two cover elements 3 are assembled as described above, and the secondary beam 20 is slid over the engaged side edges 5, 6, the upper part 21 of the secondary beam 20 will effectively lock the two cover elements in place such that no further movement is possible.

Going back to figure 4 the connection 70 between two cover elements 3, 3' is achieved in the manner described above with reference to figures 5. Where the second beam 20 is slid over the connection 70, the connection will look like the detail illustrated with reference number 71. As it is an upside-down view, the upper part 21 is lowermost close to the cover plate 3. The side edges 5, 6 are accommodated in the upper part 21 of the secondary beam 20 such that a strong, rigid connection is provided between the secondary beam 20 and the cover elements 3. In figure 7 is illustrated a cross section through a primary beam 30 which in this embodiment has a simple I-shape such that there is a main web 31 provided with an upper and lower flange 32, 33. In figures 8 a and 8 b are illustrated two embodiments of the edge beam's position on the platform. In figure 8 a the platform 1 provided with cover elements supported by first and secondary beams 20, 30 as explained above, is provided with an edge beam member 40 which is positioned inside from the free ends 20', 30' of the primary and secondary beams and below the load-carrying surface 4 of the cover elements 3.

In figure 8b is illustrated an alternative embodiment where the edge beam 40' is provided outside the distal ends 20', 30' of the primary and secondary beams. In this embodiment the edge beam 40' is provided with a shallow flange 41 ' which provides active support for the free ends 4' of the cover elements 3.

As illustrated in the cross sections of the cover elements, these are provided with a profile on the upper surface in order to render them skid safe. The cover elements may also or alternatively be provided with non-weakening apertures, thereby providing a lighter structure.

In fig. 9 is illustrated connections between a primary beam 30 and secondary beams 20,20", on the underside of a platform (which is turned up-side-down).

The connection between the primary beam 30 and the secondary beam 20", is in this embodiment accomplished by bending a portion 25 of the web 23, and fastening this bent portion 25 to the web 31 of the primary beam 30, in this example by means of bolts 41. This sort of connection is especially useful when there is no secondary beam continuing on the other side of the primary beam 30. Where, however the secondary beam 20 "continues" on the other side of the primary beam 30, a bracket 80 is supplied, often in addition to the bent portion 25. The term "continues" in this context shall be understood as the secondary beam is not integral, but cut to fit, such that two sections of secondary beams 20, are arranged in linear continuation on either side of the web 31 of the primary beam 30. The bracket 80, has a generally omega shape (Ω), having two flat flanges 81 extending away from a bent portion 82, where the bent portion 82 is shaped to configure to part of the cross section of the primary beam 30. When the bracket 80, as illustrated in fig 9, is fastened by means of bolts, to the secondary beams 20. In this manner a very strong connection is achieved, and at the same time if/when the primary beam deforms, the bracket will activate the secondary beams (including the cover elements 3 - underside showing), and in this manner distribute the load to the entire construction. The platform thereby fully utilises its strength potential. It is foreseen that a rubber gasket/member can be fitted along the periphery of platform, spanning the distance between the platforms periphery and the wall of the tower or other construction. Especially for towers, this may be important such that debris, tools etc are not able to accidentally fall from one platform and do damage to personnel or equipment on a lower platform. This aspect is not illustrated in the figures.

The embodiment described above is of cause only an example. The platform will naturally be designed and calculated to the specific requirements and loads to which it is to be subjected. It is therefore within the scope of the invention to use different profiles, having different cross sections, and use more or less profiles/beams in order to address the loads to which the platform is subjected.

Claims

1. Platform construction suitable to be arranged inside a tower structure or outside a building structure, where said platform construction comprises a plurality of cooperat- ing components:

- a second plurality of primary beams

- a third plurality of secondary beams

where the side edges of the cover elements are differently shaped, where a first side edge has a first section extending substantially vertically downwards from the horizontally arranged load bearing surface, where a distal end of the first section is shaped into a U-shaped second section, such that the free end of the first edge is pointing substantially upwards, and where the distance from the bottom of the U to the load bearing surface is "a"; and where a second side edge extends substantially vertically down the length "a" such that when the second side edges free end, of an adjacent cover element is inserted into the U, the load-bearing surfaces of the adjacent cover elements will be in one plane,

where the secondary beams has an upper and lower portion connected by a web, where the upper portion is provided with a cavity along at least a substantial part of its length, such that the connected side edges of two adjacent cover elements fits snugly inside the cavity with limited play, and

where the primary beams comprises an upper part and a lower part, and a web body connecting said upper and lower parts, where the secondary beams are connected either to the web body or to the lower part of the primary beams, such that an upper surface of the upper part is supporting the cover elements.

2. Platform construction according to claim 1 wherein the first side edge's first section is provided with a convex section or a concave section at a predetermined distance from the load carrying surface, and where the second side edge has an opposite fitting shape at the same predetermined distance from the load carrying surface, where these sections are provided on the side of the side edge facing away from the opposite side edge, whereby when the second side edge is positioned in engagement with the first side edge of an adjacent cover element, the concave and convex sections of the two side edges will mate.

3. Platform construction according to claim 1 or 2 wherein the first side edge's first section is provided with a flange extending substantially perpendicularly away from the first section at a predetermined distance from the load carrying surface, and where the second side edge also has a flange extending substantially perpendicularly away from the first section at a predetermined distance from the load carrying surface, and where these flanges are provided on the side of the side edge facing the opposite side edge, and where the cavity in the secondary beam has longitudinal slits for accommodating said flanges when the side edges are placed in the cavity provided in the upper part of the secondary b earn s .

4. Platform construction according to claim 1 wherein the means provided for connecting the secondary beams to the primary beams is a plate member arranged perpendicularly to the ends of the secondary beams, where said plate is provided with apertures, and the web of the primary beam is provided with corresponding apertures, such that a mechanical connection by means of bolts and nuts is provided, between the web of the primary beams and the plates of the secondary beams.

5. Platform construction according to claim 1 or 4 wherein a bracket is provided for connecting secondary beams to primary beams, where said bracket has a generally omega-shape, including two flat flanges extending away from a bent section, where the bent section is shaped to conform to a part of the cross section of the primary beams.

6. Platform construction according to any preceding claim wherein an edge beam is provided, where said edge beam is arranged along the periphery of the platform, and where first and secondary beams are connected to said edge beam, where the edge beam optionally may extend above the load carrying surface of the platform, or be arranged under the load carrying surface.

7. Platform according to any of claims 1 to 4 wherein the cover elements, the primary beams, and/or the secondary beams are extruded, where the material is aluminium or a metallic alloy.

8. Platform according to any of claims 1 to 4 wherein the cover elements, the primary beams, and/or the secondary beams are extruded or pulltruded, where the materials is selected from glass-, carbon or steel reinforced resin based materials.

9. Platform according to claim 6, 7 or 8, wherein some of the elements or beams are made from one type of material and other elements or beams from a different material.

10. Platform according to claim 1, wherein means for suspending the platform are provided, where said means comprises suspension beams connected to the primary beams, where said suspension beams comprise attachment brackets suitable to be connected to suspension wires, stays or the like.

11. Platform according to claim 1, wherein the platform has one or more areas not provided with cover elements.

12. Tower having a hollow interior, where at least one platform according to any of claims 1 to 1 lis arranged inside the hollow interior of said tower.