Mould for forming a material with a surface that deforms under the action of tension rods and a plate, and formwork system comprising this mould

Description

1. DOMAINE DE L'INVENTION

[0001] The present invention relates to molding a material using a mold during its hardening, the mold having a deformable surface. The surface in contact with the material deforms in a controlled manner by means of tie rods that are fixed to the surface and move by means of a rotating flange. 2. ARRIÈRE-PLAN TECHNOLOGIQUE

[0002] In the past, houses were built of stone, but later the construction of walls was made easier by using concrete blocks placed one on top of the other to create straight walls. More recently, particularly for apartment buildings, builders have been using large reinforced concrete blocks assembled to form walls. These concrete blocks are prefabricated and transported to the construction site, making building construction faster than with traditional materials. For flat, vertical walls of constant thickness, such blocks are made using a mold consisting of formwork panels with two parallel faces supported by a rigid frame to withstand the pressure exerted by the liquid concrete. These faces are made from sheet metal or, in some cases, plywood panels.It is also possible to pour the concrete on site into formwork molds that delimit a volume having the shape of the desired final profile.

[0003] Stones and concrete blocks offer the advantage of creating all kinds of surfaces, including curved ones. In concrete construction, it's possible to use panels with a predetermined radius of curvature, onto which plywood sheets are mounted. These sheets can then be bent to fit the structure. However, this system is unsatisfactory because the plywood wears out quickly and needs to be replaced regularly, resulting in significant downtime and cost.

[0004] Nowadays, bending systems for formwork, jigs, and molds with curved surfaces involve bringing together (to create convex surfaces) or moving apart (to create concave surfaces) stringers attached to the back face of the mold. These devices require numerous cylinders that are operated independently or by a chain and crank system. These cylinders are numerous, expensive, and complex to control; moreover, they require maintenance and upkeep, such as lubrication.

[0005] Solutions were then considered by combining sheet metal with an articulated frame, allowing the radius of curvature of the two sheets to be adjusted by placing them opposite each other. Such a device comprises vertical beams, regularly spaced along the sheet metal to be bent, following generatrices. These beams have omega profiles, the ends of which are welded to the sheets; other profiles are possible, such as an inverted "V". The upper part of these beams is connected to jacks that exert a force almost parallel to the plane of the sheet metal. These forces move the ends of the beams closer together or further apart, bending the sheet metal at the attachment points and giving it a specific radius of curvature.

[0006] Such devices require a jack or crank at each attachment point on the sheet metal, increasing both the cost and weight of the mold. Furthermore, adjusting each jack or crank is a tedious process to achieve the desired shape for the mold user.

[0007] FR 2 711 705 A1 discloses a mold for forming a material during its hardening comprising: a deformable surface, the first face of which is intended to come into contact with said material in a fluid form, and a deformation assembly comprising at least one row of at least two fixing points secured on the second face and associated with at least two tie rods, each of the at least two fixing points being attached by a first pivot joint to one end of a tie rod, the at least two fixing points are fixed to first ends of stringers, the second ends of said stringers being secured to the second face of the deformable surface at an approximately right angle. 3. OBJECTIFS DE L'INVENTION

[0008] There is therefore a real need for a mold that can produce a curved surface using limited mechanical means and by combining the means to exert forces on the surface, in order to reduce costs and weight. 4. PRESENTATION DE L'INVENTION

[0009] To resolve at least some of the drawbacks of the prior art, a mold is proposed for forming a material during its hardening according to claim 1.

[0010] Thus, the invention proposes a novel and inventive approach that at least partially overcomes some of the drawbacks of the prior art. In particular, the mold can produce surfaces of different shapes, which will be reproduced by the material after it hardens.

[0011] More specifically, by implementing molds with deformable surfaces and attachment points connected to a rotating flange by means of a tie rod, it is ensured that the deformation of the mold surface is controlled at each point so as to allow the desired shape to be produced by the material after it has hardened.

[0012] According to the invention, at least three attachment points are fixed to the first ends of the stringers. The second ends of said stringers are attached to the second face of the deformable surface at an approximately right angle. Rotation of said flange causes a displacement of the position of the first connections and a change in the orientation of the stringers, thus exerting torsion on said surface. In this way, the stringers act as buttresses, amplifying the torsional phenomenon of the surface. In one aspect of at least one embodiment, said flange is driven in rotation by a motor. The mold further comprises a support for a flange and a motor, which is attached at least once to said mold. In this way, the deformation of the surface is carried out effortlessly by the operator.

[0013] According to one aspect of at least one embodiment, the deformation assembly comprises three fixing points secured on the second face and associated with three tie rods, characterized in that each of the three fixing points is attached by a first pivot joint to one end of a tie rod, each other end of the tie rod being connected to a rotating flange by a second pivot joint, the rotation of said flange causing a displacement of the position of the first pivot joints and a modification of the distance between these first pivot joints triggering a deformation of the flatness of said surface, the tie rods moving under the action of the rotation of the same rotating flange.

[0014] According to one aspect of at least one embodiment, the fixing points are evenly distributed over the second surface.

[0015] In this way, it can help to facilitate the homogenization of the forces exerted by the tie rods on the deformable surface.

[0016] According to one aspect of at least one embodiment, the mold comprises a plurality of rows of fixing points, the tie rods associated with each row of fixing points moving under the action of the rotation of the same flange, the mold having as many flanges as there are rows of fixing points. In this way, with a single motor, it is possible to exert controlled deformations on several points of the surface.

[0017] According to at least one embodiment, each flange is rotated by its own motor. In this way, the deformation can be precisely applied point by point, allowing for a very large number of achievable curved profiles.

[0018] According to one aspect of at least one embodiment, the planes of at least two mold flanges intersect, preferably at right angles. In this way, it is possible to create surfaces that form part of a dome.

[0019] According to one aspect of at least one embodiment, the mold comprises a plurality of regularly spaced deformation sets on said second face of the deformable surface.

[0020] In this way, it makes it easier to homogenize the forces exerted by the assemblies on the deformable surface.

[0021] According to one aspect of at least one embodiment, said deformation sets are provided in planes substantially parallel to each other.

[0022] Also described is a mold deformation assembly according to one of the aforementioned embodiments, said assembly comprising at least one row of at least two fixing points secured on the second face and associated with at least two tie rods, characterized in that each of the at least two fixing points is attached by a first pivot joint to one end of a tie rod, each other end of the tie rod being connected to a rotating flange by a second pivot joint, the rotation of said flange causing a displacement of the position of the first pivot joints and a modification of the distance between these first pivot joints triggering a deformation of the flatness of said surface, the tie rods associated with the same row of fixing points moving under the action of the rotation of the same rotating flange.

[0023] A method for dimensioning a mold to form a material during its hardening is also described, comprising the following successive steps: determination of a desired shape to be applied to the deformable surface; determination of a material for the deformable surface; determination of the number of fixing points needed to be placed on the surface in order to deform it; determination of the thickness of the deformable surface to be implemented in order to allow the use of said material composing this surface with the desired shape and the number of fixing points determined.

[0024] It should be noted that the desired shape can, for example, be an arc of a circle, a sinusoid, a straight line or a parable, for example.

[0025] As for the material of the deformable surface, it can be determined in particular according to environmental conditions and the deformations to be achieved.

[0026] The number of fixing points on the deformable surface used to deform this deformable surface allows, in particular, the determination of the number of three-bar systems composing each of the molds.

[0027] The step of determining the thickness of the deformable surface allows, in other words, the use of said material composing this surface in the desired mechanical regime, elastic or plastic.

[0028] According to one aspect of at least one embodiment, the step of determining the desired shape to be applied to the surface includes a step of determining the complete trajectory of the deformable surface as a function of the desired shape and a range of attainable amplitudes.

[0029] It should be noted that the range of achievable amplitudes may, for example, depend on the hardenable material and the materials available to form the deformable surface. 5. DESCRIPTION DES FIGURES

[0030] Other features and advantages of the invention will become apparent from the following description, given by way of illustrative and non-limiting example, and the accompanying drawings, in which: [ Fig. 1 ]: there figure 1 represents, from a top view, a formwork system consisting of two molds, according to an example of its implementation; Fig. 2 ]: there figure 2 presents an alternative embodiment in which the flange support is secured to a mold fixing point; Fig. 3 ] : there figure 3 presents a top view of a mold in a resting position according to one embodiment variant; Fig. 4 ] : there figure 4 presents a top view of a mold with a concave surface according to the same embodiment variant; Fig. 5 ] : there figure 5 represents a top view of a mold with a convex surface, according to the same embodiment variant; Fig. 6 ] : there figure 6 presents a perspective view of a mold having a deformable surface under the action of several three-bar systems; Fig. 7 ] : there figure 7 represents a variant of a mold design comprising several flanges animated in rotation by their own motors; [ Fig. 8 ] : there figure 8 represents in perspective a surface deformed by two three-bar systems whose planes intersect at right angles; Fig. 9 ] : there figure 9 presents the mathematical model of a mold possessing a set of deformations. 6. DESCRIPTION DETAILLEE D'UN MODE DE REALISATION

[0031] There Fig. 1 The figure represents, in a top view, a formwork device, or system, consisting of two molds, according to an example of an embodiment. Each of these molds 1 has a concave deformable surface 2 and a convex deformable surface 3, the terms "concave" and "convex" being chosen arbitrarily taking into account the position of the device as shown in the figure.

[0032] Depending on the device's position, surface 2 can be more convex and surface 3 more concave. The present device allows for the creation of a cavity 4 extending vertically between the two deformable surfaces 2 and 3, the lateral edges of the two deformable surfaces being able to be closed by a U-shaped wall 5.

[0033] In this way, the first faces of the molds are placed opposite each other, and the space between these first faces, which is intended to contain the material in its fluid form, forms cavity 4.

[0034] The present invention allows the flatness of a surface 2 or 3 to be modified by mechanical means. This surface constitutes a mold intended to contain a material that is initially in a fluid form and subsequently solidifies. This material is typically concrete, the formwork device illustrated by the Fig. 1 It allows, in particular, the manufacture of concrete walls with a curved surface.

[0035] This mechanism for deforming a surface can be used in other applications that require a modification of the flatness of a surface, for example a mold for making hollow parts, a system for opening and closing hoppers, skips, tanks, locks, etc., a means of sealing a hole in a ship's hull by applying a surface that perfectly conforms to the hull, a means of gripping parts of various shapes, etc.

[0036] This mechanism for deforming a surface can also be used to modify the entire profile of an aircraft wing (chord length, thickness, sweep, and thus the angle of attack, all with a single mechanism), so as to modify its lift and drag characteristics during the different phases of flight. All the elements of the wing deformation mechanism, including the actuator, are housed within the wing's thickness. The mechanism itself—shafts, flanges, tie rods, or connecting rods—serves as the wing's structure, thus replacing traditional ribs. Each mold of the present invention comprises a deformable surface 2 or 3, and at least one deformation assembly including at least one row of at least two attachment points 6 on the face opposite to that intended to contain a material.Each of these fixing points 6 is attached by a pivot joint 7 to one end of one of the tie rods 8, which are typically straight bars of a determined length. The other end of each tie rod 8 is connected to a rotating flange 9 by a second pivot joint 10. The flange 9 has a plurality of holes 11 preferably located on its periphery. The ends of the tie rods 8 have a pin with a circular cross-section and whose axis is perpendicular to that of the tie rod; the pin fits into a hole 11, forming a pivot joint. The flange 9 has a rotation axis 12 which rotates with the aid of a motor 13. A belt. 14A drum on the flange is connected to a pulley on the motor, but any other drive system is suitable for rotating the flange 9, including a manual crank system or a motor driving a rack and pinion. This drive system must be powerful enough to deform the surface 2 or 3. The rotating flange 9 and the motor 13 are fixed to a support 15 which absorbs the torsional forces acting on the tie rods 8.

[0037] By rotating, the flange 9 exerts tensions and pressures on the tie rods 8 which then displace the position of the pivot joints 7, resulting in a change in the distance between these first pivot joints and a deformation of the flatness of said surface.

[0038] Surfaces 2 and 3 are preferably made of sheet metal, although other materials such as wood, in the form of plywood panels, are also suitable. Wood has the advantage of being inexpensive but the disadvantage of leaving a less smooth surface than sheet metal and wearing out more quickly. Other plastic materials, such as PVC sheets, can also be used. The surfaces that deform under the pressure of the fixing points should preferably be thick enough to withstand the pressure of the fluid material in contact with them. It should be noted that the surfaces must be flexible but do not need to be elastic or assume a fixed position, as the tie rods can constantly maintain the surface flatness using a motor or a manual mechanism.

[0039] The presence of unused holes 10 on the flange for pivot joints allows for increased precision in torsional adjustment and variation of the deformation applied to the surface. Positioning the tie rods in either of these holes also allows for the use of tie rods of different lengths. It is clear, and will be seen later in this document, that the flange 9 can take on various shapes, and that the axis of rotation is not necessarily at the center. Advantageously, the axis of rotation 12 passes through an orifice identical to the holes 10, which simplifies the manufacture of the flange.

[0040] Each mold 1 allows the associated surface to be flexed according to a predetermined radius of curvature and a predetermined length. Such molds can be arranged end to end to form a larger surface that can take any shape. It is thus possible to imagine that the molds 1, which are the subject of the present invention, produce a wave shape, the succession of molds alternately presenting a concave surface, then a convex one, then a concave one again, and so on.

[0041] There Fig. 2 This presents an alternative embodiment in which the support 15 is secured to at least one attachment point 6 of the mold. This securing consists of connecting the support 15 to a mold attachment point using rigid bars 16. In this way, the forces applied to the surface 2 or 3 are transferred to the support 15 via the tie rods 8. This securing is achieved by the fact that the deformable surface, the tie rods, the support, the flange, and the motor form a single assembly that is transported as a unit.

[0042] There Fig. 3 is a top view of a mold in a resting position according to an alternative embodiment. This alternative embodiment consists in the fact that the fixing points 6 are significantly away from the deformable surface.

[0043] According to the example shown, the mold includes three tie rods 8 and has three fixing points 6 that can be joined on a second face of a deformable surface of said mold, each of the three fixing points 6 being attached by a first pivot link D1, D2, D3 respectively to one end of a tie rod 8 distinct among the three tie rods 8, each other end of tie rod 8 being connected to the rotating flange 9 by a second pivot link C1, C2, C3 respectively.

[0044] More specifically, here, stringers 20 connect the other end of the tie rod to the fixing points 6 via the pivot links respectively marked D1, D2 and D3.

[0045] This type of mechanism for deforming a surface using three tie rods is also subsequently called a "three-bar system".

[0046] Surface 2 is fixed to a fixed support point labeled "A". Flange 9 rotates around an axis labeled B, which is fixed to support point A. These two fixing elements can, for example, be mounted on a frame. The stringers 20 are securely fixed to the face opposite the one intended to contain the material during its hardening; the fixing points are labeled A1, A2, and A3. The stringers are advantageously fixed by welding. Angle brackets can be used to stiffen the connection between the axis of these stringers and the plane of surface 2 or 3, and to maintain this angle. This angle is preferably, but not exclusively, 90 degrees, with a margin of 5 degrees.

[0047] The position shown in this figure is the rest position of surface 2 (it being understood that it could be identical for surface 3) when no force is applied to it by the tie rods. When flange 9 is rotated counterclockwise by a motor, the tie rod marked Tie Rod 1 will push the pivot joint D1 to the right, causing point A1 to rise. The axis of the spar 20 will tilt to the right, causing an upward twist of surface 2. Similarly, Tie Rods 2 and 3 will undergo the same movement and push the pivot joints D2 and D3 to the right, thus contributing to the upward bending of the surface and amplifying it as the point on surface 2 moves away from the support point A.

[0048] There Fig. 4 is a top view of a mold having a concave surface according to the same embodiment variant. This figure represents a position of the surface 2 when the flange 9 has rotated counterclockwise, to a position which may be that defined by the elastic limit of the material of the surface 2.

[0049] As can be seen in the figure, the tie rods and the stringers can cross, so it is preferable to place them in space on different planes, these planes being parallel to that of the flange.

[0050] There Fig. 5 is a top view of a mold having a convex surface according to the same embodiment variant. This figure represents a position of surface 2 when flange 9 has rotated clockwise, to a position which may be that defined by the elastic limit of the material of surface 2. In this position, other tie rods and stringers may cross.

[0051] THE Fig. 3, 4 And 5 They present molds with 3 tie rods and 3 longerons in addition to a support point, according to a preferred example of the design, allowing for greater compactness and an engine with average power. It is clear that the number of tie rods and longerons can vary, and that by increasing the size of the flange, this number can become significant.

[0052] It should also be noted that the mold can include a plurality of deformation sets.

[0053] For example, this plurality of deformation sets can be placed so that the deformation sets E are regularly spaced on said second face of the deformable surface of a mold.

[0054] In this way, it makes it easier to homogenize the forces exerted by the assemblies on the deformable surface.

[0055] For example, these deformation sets can be arranged in planes that are substantially parallel to each other. In this sense, the Fig. 6 This presents a perspective view of a mold having a deformable surface under the action of several three-bar systems, that is, a mold exhibiting a plurality of deformation assemblies E, equipped in this embodiment with three tie rods. The surface 2 of this mold supports several rows of fixing points to which as many longitudinal members 20 are attached, themselves connected to the same number of tie rods 8 connected to the same flange. In this way, it is possible to multiply the fixing points and the deformation of the surface 2 is more precise. The rotation of all the flanges of such a mold can be controlled by a single motor, and thus becomes synchronous. In this way, the deformation produces a cylindrical surface.

[0056] According to one alternative embodiment, which is illustrated by the Fig. 7 ,Each flange 9 is rotated by its own motor. Deformations occur independently of where they are applied and in different directions. This makes it possible to produce any type of surface. As can be seen in this figure, the flanges viewed in a direction normal to their surface are not inclined at the same angle, depending on the rotation imposed by their associated motor.

[0057] There Fig. 8 The image shows a surface 2 subjected to torsion by two three-bar systems E, whose planes intersect at right angles, to produce a hemispherical shape on said surface. Such an arrangement makes it possible to create parts of a spherical dome, and by assembling a number of molds of this type and placing them side by side, a hemispherical surface can be produced.

[0058] After showing the different equipment, we will now detail how to implement them and how to calculate the dimensions of the elements constituting a mold.

[0059] The calculation of the elements constituting a mold is done through a mold dimensioning process to form a material during its hardening, comprising the following successive steps: determination of a desired shape to be applied to the deformable surface; determination of a material for the deformable surface; determination of the number of fixing points needed to be placed on the surface in order to deform it; determination of the thickness of the deformable surface to be implemented in order to allow the use of said material composing this surface with the desired shape and the number of fixing points determined.

[0060] An example of such a mold dimensioning process, in this embodiment, includes the following steps: 1. Determine the desired curvature to be applied to the deformable surface (e.g., circular arc, sinusoid, straight line, parabola, etc.). 2. Determine the complete trajectory of the surface's evolution, based on the desired curvature and the achievable amplitude range. 3. Determine the surface material based on the environmental conditions and the desired deformations. 4. Determine the number of fixing points on the surface used for deformation, and therefore the number of three-bar systems composing the mold. 5. Geometrically dimension the three-bar systems. 6. Determine the thickness of the deformable surface to ensure the material composing this surface can be used in the desired mechanical regime, elastic or plastic.

[0061] There Fig. 9 They present the mathematical model of a mold possessing a deformation system. The mold is thus composed of a set of three-bar systems. The number of three-bar systems included in a mold is not fixed, but it is at least one, and depends on the deformation curve as well as the desired precision. The mold of the invention deforms the surface in the planes of each three-bar system, in other words, the plane containing at least that of the flange.

[0062] The mechanism is activated by rotating an input crank, labeled Cb, around point "B". This rotation can be achieved with a handle or a motor actuating the crank (see segment BQ in the figure below) of each three-bar linkage. At the other end of a three-bar linkage is a circle representing an output crank, with A and P as its attachment points. This crank is driven in rotation by the tie rods represented by lines "a" and "d".

[0063] The dimensioning of three-bar systems is performed using an optimization method. The complexity of the equations describing the proposed bending system (see below for the equations governing each three-bar system) does not allow for the determination of an analytical solution from which the calibration of the (numerous) system parameters could be derived. Therefore, various optimization methods can be used: manual graphical analysis (using geometric visualization software), manual numerical analysis (using a spreadsheet), automated numerical analysis (using an algorithm executed by a computer, etc.).

[0064] A three-bar system is governed by the following geometric equation: a 2 + b 2 + c 2 − d 2 − ab cos t + 2 ac cos u − 2 bc cos u − t = 0 Or a, b, c and d are the dimensions of quadrilateral APQB, and u And t are respectively the exit angles BAP ^ and from the outset B 2 BQ ^ .

[0065] The equation above allows us to establish the relationship between the rotation supplied by the motor located at B to the input crank BQ, and the rotation supplied to the output crank AP.

[0066] The imposed displacement of point P constrains the deformation of the sheet metal. In the actual case, the crank AP constitutes a fraction of the sheet metal and is fixed at A, thus the displacement of point P deforms the sheet metal.

[0067] The amplitude of displacement of point P, around the circle (CA), is guaranteed by respecting the following inequalities: a + b ≤ c + d passage par le point A 1 b + c − a + d b + d − a + c ≥ 0 passage par le point A 2

[0068] The equations above must be studied to ensure that point P can follow the desired shape of the deformable surface. The evolution of the displacement of point P in each three-bar system is calibrated relative to that of point P in the other three-bar systems in order to impose the desired curvature of the deformable surface.

[0069] It should be noted that the proposed mold allows a sheet of metal to be deformed into a desired curvature, achieving the most regular curvature possible. Such a mold, and by extension the formwork system, therefore allows the desired shape with the desired curvature to be obtained.

[0070] In this way, the resulting molded part can, for example, exhibit a regular curvature. It can also, as another example, exhibit a gradual curvature.

[0071] It should be obvious to those skilled in the art that the present invention allows for embodiments in many other specific forms without departing from the scope of the invention as claimed. Therefore, the present embodiments and variations should be considered illustrative but may be modified within the scope defined by the attached claims.

Claims

1. Mould (1) for shaping a material during hardening thereof, having - a deformable surface (2; 3), a first face of which is intended to come into contact with said material in a fluid form, and - a deformation assembly comprising at least one row of at least two fastening points (6) secured to a second face of said deformable surface and associated with at least two tie rods (8), each of the at least two fastening points (6) is attached by a first pivot connection (7, D1, D2, D3) to an end of a tie rod (8), each other tie rod end being connected to a rotary plate (9) by a second pivot connection (10, C1, C2, C3), the rotation of said plate causing the position of the first pivot connections to move and the distance between these first pivot connections to be modified, resulting in deformation of the planarity of said surface (2; 3), the tie rods (8) associated with a given row of fastening points moving under the action of the rotation of a given rotary plate (9), the at least two fastening points (6) are fastened to first ends of longitudinal members (20), the second ends of said longitudinal members (20) being secured to the second face of the deformable surface at an approximately right angle, the rotation of said plate (9) causing the position of the first connections to move and the orientation of the longitudinal members to be modified, thus applying twists to said surface (2; 3).

2. Mould according to Claim 1, characterized in that said plate (9) is driven in rotation by a motor (13), the mould also has a support (15) for supporting a plate and a motor and which is secured to said mould at at least one point.

3. Mould according to either one of the preceding claims, characterized in that said mould has as many plates as there are rows of fastening points.

4. Mould according to Claim 3, characterized in that each plate is driven in rotation by its own drive system.

5. Mould according to one of the preceding claims, characterized in that it comprises a plurality of deformation assemblies (E) regularly spaced apart on said second face of the deformable surface (2, 3).

6. Mould according to the preceding claim, characterized in that said deformation assemblies (E) are formed in planes that are substantially parallel to one another.

7. Formwork system for hardenable material comprising at least two moulds according to one of Claims 1 to 6, the first faces being placed facing one another, the space formed between said first faces being intended to contain the material in its fluid form.