The invention relates to the field of tensegrity structures.
It proposes in particular a mechanical assembly forming a support (platform for example) of the type with a foldable tensegrity structure.
In particular, it finds advantageous application in the development of temporary structures for access to sites such as tourism sites or swimming areas.
Despite awareness by public authorities intending to improve the suitability of tourism sites for persons with reduce mobility, it is noted that in certain regions, the seacoast remains difficult of access for this type of user. In fact, many tourism sites do not propose any structure allowing fully autonomous access for swimming.
Currently, access to the ocean for a person with reduced mobility can be accomplished by the use of a specific floating wheelchair which requires outside aid.
For autonomous access, there exist fixed structures (www.unfauteuilalamer.com), but they impact, by definition, the installation site.
In certain regions subjected to obligations regarding the defense of the environment, non-temporary installations are not viable solutions. For example, certain laws aiming to protect the coast impose a structure that can be disassembled and transported, having no permanent anchoring element in the ground, and which must allow the site to be returned to its initial state at the end of the concession.
Temporary structures such as floating pontoons that can be disassembled exist (www.belrive.fr/), but these remain poorly suited to seacoasts for reasons of stability, because they require considerable anchorage. Moreover, the load capacity is relatively small with regard to the volume occupied in the disassembled state, limiting their versatility.
Also known are modular solutions for forming platforms which can be disassembled, based on scaffolding components. These modular scaffolding systems allow the implementation of any type of platform capable of supporting considerable loads, on point supports. The components must however be adapted so as not to have considerable overweight. The point supports can be numerous and must be individually adjusted. The assembly of a structure implements separate components requiring a large number of operations; such solutions are therefore constraining in installation time and in labor.
There exists therefore a need for placing a lightweight, versatile installation with a low environmental impact, easily deployable and designed for temporary use.
Publication WO2005/111343 describes a deployable structure which can be assembled with other similar structures to form an installation such as a platform. However, such installations, based on the assembly of identical elementary cells, do not offer flexibility in terms of assembly, thus the cells cannot have different dimensions. Moreover, the placement of installations requires a large number of cell assemblies.
Also known are installations based on tensegrity structures.
Tensegrity is the facility of a structure stabilize itself through the interplay of forces of tension and compression which are distributed in it and achieve equilibrium within it. Structures established in a state of tensegrity are therefore stabilized, not by the resistance of each of their constituents, but by the distribution and the equilibrium of the mechanical stresses in the totality of the structure.
Thus, a mechanical system including a discontinuous system of compressed components within a continuum of tensioned components can find itself in a state of stable equilibrium. Which means, for example, that by connecting the bars using cables, without connecting the bars together directly, it is possible to constitute a rigid system.
For this reason, a tensegrity structure is a reticulated spatial system, the stiffness and stability of which arise from the combination of compression in the bars and tension in the cables.
Publication FR 2823287 describes a tensegrity system in the form of a reticulated structure with self-constraints of its various components, to achieve light construction structures of the type of a framework, panel or other similar assembly. However, this publication does not describe the notion of modularity, of assembly of tensegrity structures to form temporary platforms in poorly accessible zones in particular.
Such structures have the advantage of being particularly light and therefore easy to place. They are particularly suited for environments which it is desired to preserve.
The document “Les systèmes de tenségrité déployables: application à l'accessibilité de la baignade en mer [Deployable tensegrity systems: application to the accessibility of bathing in the sea]” (J. Averseng, F. Jamin, J. Quirant—Rencontres universitaires de Génie Civil, May 2015—https://hal.archives-ouvertes.fr/hal-01167613/document) describes a grid tensegrity structure, foldable and un-foldable, composed of a set of bars and of nodes connected to one another. The different nodes and bars of this structure are contiguous.
This structure has the advantage of being deployable on site and to allow the implementation of stable, light and reusable platforms.
Even so, it is complicated to handle and to place when it is desired to create platforms with large dimensions.
There exists, therefore, a need for a mechanical assembly forming a support (platform for example) of the type with a foldable tensegrity structure which allows the implementation of structures of large dimensions and which is easy to assemble or disassemble.
A general goal of the invention is to propose a mechanical assembly forming a support of the type with a foldable tensegrity structure which does not have the disadvantages of the tensegrity assemblies of the prior art.
Another goal of the invention is to propose a mechanical assembly with a foldable tensegrity structure which is particularly adapted to the implementation of structures with large dimensions.
Yet another goal is to propose a mechanical assembly with a foldable tensegrity structure which is easy to assemble and disassemble, and in particular less costly in labor and in installation time.
Another goal of the invention is also to propose a mechanical assembly forming a support of the type with a foldable tensegrity structure which is versatile, easy to assemble and disassemble and easy to transport.
Another goal, also, is to propose a structure which—while still having excellent mechanical properties—does not require durable anchorage elements in the ground, is light and has a low environmental impact.
According to one aspect, the invention proposes a mechanical assembly with a tensegrity structure,
characterized in that
According to yet another aspect, it also proposes a support structure which includes a mechanical assembly of the aforementioned type of which several modules are deployed and disposed so as to be adjacent, each of these modules including at least one assembly edge node which is positioned in line with an assembly edge node of another adjacent module and which is connected to it by a connection element in tension or in compression perpendicular to the planes of the nodes of these two modules, said structure also including cover elements extending between successive modules.
Mechanical assemblies and structures of this type are particularly suited for the implementation of temporary structures, such as the scenic space catwalk type.
The invention also proposes a method for mounting such a support structure.
Other features, aims and advantages of the present invention will appear upon reading the detailed description that follows, with reference to the appended figures, given by way of non-limiting examples and in which:
With reference to
As illustrated in
More generally, cables and/or tensioners can be replaced by any element allowing a tension connection: chains, straps, etc. . . .
The module comprises the assembly of two parallel horizontal layers of nodes 40. Thus, represented by, respectively,
The topology of the module, representing the assembly of layers 2 and 3, is inspired by weaving: a network of compressed elements, formed of sub-assemblies of bars 10 alternately connecting nodes 40 of one layer to another, mirrors the warp and weft threads which form fabrics.
The peripheral cables 20b and 20c situated at the periphery of the module also allow the connection of the two layers 2 and 3 by connecting the nodes 40 at the periphery of the module, alternately, from one layer to the other.
The peripheral cables 20b are said edge cables; they connect the nodes 40 of the lower layer 2 to the node 40 of the upper layer 3, said nodes being position on one side of the module.
The peripheral cables 20c are said corner cables; they connect nodes 40 of the lower layer 2 to the node 40 of the upper layer 3, said nodes being positioned on two consecutive sides of the module.
The edge cables 20b and the corner cables 20c can have different inclinations.
With respect to the plane of the layers, the cables 20a have a generally horizontal inclination, the peripheral cables 20b and 20c, a diagonal orientation, and the cables with turnbuckles 30 a vertical orientation.
The bars 10 can be made of a metallic material such as aluminum, or of a metallic alloy. Other types of materials are possible, such as wood, plastic (PVC for example), composite (glass, carbon fiber, fibrous concrete, . . . ). The nodes 40 are preferably made of a high-strength material such as steel. The cables 20 and the tensioners 30 are also preferably made of steel; they can also be made of fibrous materials.
The compressed assemblies 10 are also assembled by means of elements called “tensioners” 30, passing between the nodes 40 of each layer 2 and 3, and which allow stiffening the structure of the module. The “interior” tensioners 31, shown in
Thus, with reference to
The other types of nodes 40b, the interior nodes of a layer, have a node 40b of the other layer opposite in the same vertical plane, orthogonal to the layers. Thus, these nodes are connected to 4 other nodes 40 of the same layer by layer cables 20a, and by a tensioner 30 to an opposite node 40b of the other layer.
The tensioners 30 between two nodes 40, illustrated in detail in
The cable and turnbuckle assembly 30 advantageously allows controlling the tension of the cables. With respect to another element which could for example be a threaded rod, cables with turnbuckles allow tension to be released while still keeping the tensioning elements attached to the nodes 40, thus facilitating the deployment of the module. Moreover, these elements also allow a lighter structure to be obtained.
A node 40 can also include a coupling element 41 allowing the attachment of the tensioners 30. This element is advantageously a means of attachment of the ring type disposed on a lower face of a node 40 of the upper layer 2 and on an upper face of a node 40 of the lower layer 3.
The nodes 40 of the lower and upper layers can be identical. In this configuration, the nodes 40 of the lower layer 3 are turned 180° with respect to the nodes 40 of the upper layer 4.
The release of tension by the turnbuckles 31, also allows, during folding of the module, to control the orientation of the nodes 40 for optimized stowage of the bars in the folded state.
The connection between the bars 10 (nodes 40) allows the folding-unfolding of a module from a bundle, illustrated in
The operation of folding/un-folding the structural module is allowed by the configuration of the nodes 40, which include means of articulated attachment 46 of the bars 10, illustrated in
These means are typically 1 or 2 in number, and can be of the pivot connection type, or of the ball joint type. The nodes 40 can combine the two types of articulation. Lightness and the folding characteristic facilitate handling. Moreover, the nodes 40 allow optimally compact stowing (contiguous parallel bars 10).
Modules of all dimensions (shapes and heights) in space can be generated within the limits of their portability, for example according to standard NF X35-109 relating to the load carried by workers in France. For this reason, the limit of weight to be handled during working activities for one person is a maximum of 30 kg.
Thus a typical module, as shown in
The dimensions, such as the height or the mesh (spacing between the nodes 40 of the same layer) can be adjusted at will depending on the dimensions of the elements which are selected accordingly. For example, the dimensions of a module can typically be 4 m×4 m, the height being adjustable from 0.5 to 1.50 m depending on the selected inclination of the bars 10.
Two modules having the same mesh can be distinguished by their height. Thus, for a given mesh, the height of the modules is determined by varying the length of the cables with turnbuckles 30, the length and the inclination of the peripheral cables 20b and 20c, and of the bars 10.
As illustrated in
In one embodiment, each cable 20 is attached between two nodes 40. In another embodiment, the cables 20 pass through the nodes 40, and said nodes 40 include a system, such as sleeves, allowing a portion of the force of the cables 20 to be transmitted to the nodes 40.
By the use of cables 20, 34 and 35 as tensioned elements the structure naturally offers a certain visual transparence, but also with respect to the actions which affect the elements, such as swell in a context of semi-submersion at the edge of the sea. Moreover, the cables 20, 34 and 35 are elements which make the system very light, by optimizing the use of the constitutive material, and therefore the mass, so that strictly necessary with respect to stiffness and mechanical strength.
The structural module has the possibility of not resting on the ground directly by means of the nodes.
Thus, as illustrated in
Due to its lightness and its stiffness, the implantation on the ground requires a reduced number of support points, which perturbs the environment very little. Difficult and sensitive sites can be made accessible by a platform. The occupation of the site can be only temporary, disassembly allowing a return to the initial state.
Moreover, the adjustable height base elements 43 allow the flatness of the system to be easily adjusted.
With reference to
This attachment is accomplished by an element including a groove which engages by sliding, like a rail mechanism, on the upper portion of a node 40 of the upper layer.
The coupling element 44 is for example in the form of a cylinder with a collar on its top on the upper portion of a node 40 allowing an element, such as a support beam 50 comprising a groove of complementary shape, typically a T-shaped groove, to engage by sliding in said upper portion of the node 40. The support beam element 50 is positioned on at least two adjacent nodes 40, perhaps three or more.
The support beam element 50 also includes on its upper face a portion having a T-shaped profile allowing the engagement of an element including a complementary groove.
To allow the attachment of the cover, it is possible for example to use a junction bar 51 which is embedded in the support beam element 50. The junction bar 51 allows, on either side of it, to attach the installation of floor slats 52. The latter are interlocked by their widths between the support beam 50 and the junction bar 51.
In another embodiment, the features of the support beams 50 and the junction bars 51 can be combined into a single beam positioned over at least two adjacent nodes 40, perhaps three or more, and comprising a specific section allowing, among other things, the attachment of the cover.
The coupling element 44 therefore offers the installation of cover 52 by their widths between two rows of adjacent nodes 40 each including a junction bar 51.
As shown, the bars 10 are disposed in parallel rows 11, and in parallel rows 12 perpendicular to said rows 11.
The peripheral nodes 40a (including a single connection to a bar 10) disposed at the ends of the rows of bars 11, define two sides 13 of the module.
Likewise, at each end of the rows of bars 12, two sides 14 of the module are defined.
The sides 13, 14 are therefore defined by an assembly of peripheral nodes 40a connected by cables 20, disposed in the same vertical plane, orthogonal to the rows of bars 11, 12, to which these nodes 40 are connected.
In the lower part of the figure, the peripheral nodes 40a have been represented by solid circles (black nodes), while the interior nodes (nodes 40b) have been represented by hollow circles (white nodes).
For each side 13, 14, the number of nodes 40a in the high position is determined, therefore belonging to the upper layer, and the number of nodes 40a in the low position, therefore belonging to the lower layer.
When the number of nodes 40a in the high position is in the majority, the side is called “+”; in the reverse case, the side is called “−.”
The elementary structural module illustrated in
two nodes with “+” ends;
a single node with “−” ends.
Shown on the right portion of the same figure is a network of support beams 50 used on these nodes.
These beams are all mutually parallel and extend in a direction Δ1 connecting one and the other of the two nodes of the “−” ends. In the figure, the direction Δ2 is perpendicular.
The assembly of modules with identical structure, as shown in
In the case where structure modules of the type of those of
More generally, a module with a given mesh structure (spacing between the nodes 40 of a layer) can be assembled edge to edge with another module having the same mesh structure. Thus, the two modules can be assembled along an edge having complementary nodes between the two modules (the nodes 40a of the upper and lower layers of a module being placed opposite respectively the nodes 40a of the upper and lower layers of the other structural module). In the case of
The assembly of several modules edge to edge also allows, in a simplified manner less costly in labor, the implementation of platforms with multiple architecture (for example,
Moreover, modules of different heights can be combined to adapt to the morphology of the terrain. The structure of the module and the arrangement of the nodes 40 thus offers great flexibility with regard to possible implementation (see for example
The assembly of different modules can also be stabilized and reinforced by the installation of cover elements between the different structural modules.
The installation of a support beam 50 is therefore carried out, as described previously, on the coupling elements 44 of the nodes 40a, the support beam preferably rests on at least 2, perhaps 3 nodes 40a.
The assembly side has in the same vertical plane an alternation of nodes 40a of the first and second module, the support beam 50 therefore rests on at least one node 40a of the upper layer of the first module and one adjacent node 40a of the upper layer of the second module, which has the advantage of stiffening the assembly.
Thus, the connection between different structural modules can be carried out, on the one hand thanks to tensioners 30 between the complementary nodes 40a of the modules, and on the other hand by cover elements which allow reinforcing and ensure the stability of the assembly.
These connection elements also allow limiting the number of ground supports of the assembled structure. In
For this reason, the assembly of two modules will rest on 6 ground supports, the assembly of three modules, 8 supports, etc. The number of ground supports of an assembled structure thus remains limited.
Thus, the simple addition of elementary modules, which can have any dimensions of length, width and height, allows different spatial configurations to be implemented.
The advantage of using modules in the repetitiveness of assembly by connection of nodes 40a that are complementary from one module to the other. Unlike elementary cells, the monolithic structures of which are formed by adding structural elements step by step, the system according to the invention accomplishes a monolithic structure with a reduced number of structurally independent modules, with variable shapes and heights and geometrically complementary.
The structure thus composed has the benefit of a certain advantage in terms of robustness because a local failure remains limited to the module concerned.
Each module forms, in the folded state, a contiguous bundle, easily transportable and storable in a reduced volume and, in the deployed state, a rigid structure supporting a delimited cover and being able to receive many independent pieces of equipment (guardrails, stairs, ramps, etc.).
Depending on the dimensioning of the bars and of the cables, justifiable by a simple calculation code, each module is limited to a mass of 40 kg and can take up operational loads up to 500 kg/m2 which is required for example in the case of bleachers which can be disassembled.
Thus, the structure satisfies two often opposed constraints: lightness and mechanical performance.
The shape of the modules allows, by juxtaposition and connection, the constitution of a monolithic structure with pathways of any length and with varied spatial configurations.
In a coastal zone, the bearing structure can be implanted in semi-submersion so as to constitute a platform of suitable height allowing accessibility to swimming areas and the practice of nautical activities with full autonomy. The system being light, its impact on the environment and on the implantation site is essentially nil, this being restored to its original state after disassembly.
This structure consists of a tensegrity grid M, a set of stilts 101 and a set of cover plates 102 applied to the structure.
The tensegrity grid M is a conventional grid formed from bars 110 corresponding to the compressed elements, of connecting elements in tension (tensioning cables, etc.) 120 connecting a set of nodes 140 on which the bars 110 are articulated so as to be foldable/un-foldable.
The stilts 101 are of two types: edge stilts 101a and corner stilts 101b.
Edge stilts 101a are vertical stilts which extend between an edge node 103b of the lower layer of the elementary module M and the corresponding edge node 140e of the upper layer of the same elementary module M, distinct from a corner node (node 140c) of said structure.
The corner stilts 101b consist of two bars 104b and 105b which extend in a V shape from the same corner node 103 in the lower layer.
This node 103 is vertically opposite to a node 140b immediately adjacent to a corner node 140c, these nodes being added to the upper layer so as to offer 4 support points to the cover plates in this zone.
One of the bars (bar 104b) extends vertically between the node 103 and the node 140b.
The other bar (bar 105b) extends obliquely between the node 103 and the corner node 140c.
It thus ensures the taking up of a vertical force with respect to the corner node 140c.
Two cables 106a and 106b extend horizontally between the nodes 140b and 140c, and between 140b and 140d, ensuring the taking up of horizontal forces with respect to the corner node 140c.
Different structural modules (support grids) are of course possible for a cover of the plate type as shown in
Column A) of
For its part, column C illustrates the cover implemented by means of plates supported on the nodes by their four corners.
In this assembly, the corner stilts of the two elementary modules M1 and M2 are eliminated, only the edge stilts 101a subsisting in this plane.
The corner stilts 101b are also retained, at the corners of each of the two elementary modules M1 and M2, in the other edge planes (perpendicular planes).
In the structure that has just been described, the support beams are not necessary. The cover elements—which in this case are plates—are supported directly on the nodes, which include coupling elements adapted for this purpose.
In this means of attachment—which is given here only by way of an example—the nodes 140 each comprise several spurs (four in this case) to receive the corners of the plates 102. After the placement of the plates, a retaining cap 106 is applied above the node 140 at the intersection of four plates, on the upper face thereof, and is screwed to said node 140.
Such structures allow better interfacing during the placement of the cover.
Number | Date | Country | Kind |
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1654269 | May 2016 | FR | national |
Filing Document | Filing Date | Country | Kind |
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PCT/EP2017/061533 | 5/12/2017 | WO | 00 |