EP2450501A1 - Device for moving a slab and/or balcony formwork platform - Google Patents

Abstract

The device has telescopic struts (1) on which a slab and/or balcony formwork platform is rested. The struts are configured for moving the platform without crossing between a folded position of installation and a deployed position, where the platform achieves height of service. The struts include sliding elements formed of a shaft (10) and slides (11, 12) stacked one on another in a telescopic manner. Removable motorization units (M1, M2) of struts assure sliding of elements. Each of the struts is formed of two pairs of sliding elements, where each pair of the elements has motorization units. Independent claims are also included for the following: (1) a slab and/or balcony formwork system, comprising a formwork platform (2) a method for forming a slab and/or balcony.

Description

Technical Field of the Invention

The invention relates to a device for moving a platform slab formwork and / or balcony. The invention also relates to a system and method for forming a slab and / or a balcony using such a device.

The invention relates to the general technical field of the construction of concrete slabs or balcony poured on site. It relates more specifically to the technical field of devices for assembling a slab formwork near the lower floor and bring it to the final height corresponding to the height of the slab or balcony to achieve.

State of the art

On most sites, the formwork consists of a support structure on which rests a formwork skin intended to receive the concrete. The support structure is generally constituted by primary beams resting on props and supporting the entire load, and secondary beams resting on said primary beams. Plywood forming the formwork skin are positioned on the secondary beams. Primary and secondary beams, as well as plywood, are standard formwork elements used around the world.

For safety reasons, certain labor laws require construction companies to implement protection measures for workers against the risk of falling during formwork operations. In practice, the formwork device, before pouring concrete, is at a height greater than 2 m. It is thus common that the workers are obliged to climb on scaffolding, nacelles, or on the formwork itself in order to set up the formwork at the desired height. Such a practice exposes workers to a risk of falling, but is also costly in time and labor and requires heavy handling of heavy equipment.

It therefore appears particularly advantageous to provide formwork that can be assembled near the lower floor, at man's height, and can be brought automatically to the final height while the workers remain on the lower floor.

This type of lifting device is for example described in the following patent documents: DE 2657111 (ENOR NOMINEES); DE 1559049 PLUECKEBAUM); DE 1759423 (KISTLER); FR 2.723.758 (DINGLER); FR 2,597,534 (LETRICHEZ); FR 2.742.787 (VIANDON); FR 2.760.A.82 RICARD ); US 5,616,349 (SASAKI); US 4,148,852 (DASHEW); US 3,700,070 CALABY); JP 7293002 (SASAKI).

The technical solutions presented in these documents have the main disadvantage of requiring a specific formwork structure necessarily adapted to the lifting device.

The patent document FR 2,934,291 (DEMINGEON-MOULINS) relates to a universal slab formwork device comprising several vertical poles of fixed length and equipped with elements intended to support said formwork. The support elements are able to move vertically along the masts between a low position where the formwork is located near the lower floor and a high position where the formwork is located at the height of the slab to achieve. The support elements comprise pins on which the primary beams rest: in low position, the masts through the formwork skin, the latter leaving free linear hoppers to the right of said masts; and in the high position, said formwork skin protrudes from the upper end of said masts, compensation strips coming to plug said linear hoppers.

Although effective, the formwork device described in this document has drawbacks. Indeed, the fact that the vertical poles pass through the formwork skin requires relining the linear free hoppers. This is not only an extra costly step in time, but also prevents the entire formwork from being built in the down position.

To remedy this problem, it is known from the patent document FR 2.823.521 (BOUYGUES), a device for moving a formwork platform comprising telescopic stalls on which is intended to rest said platform. These props make it possible to move the platform, without crossing it, between a folded position of installation and a deployed position where the platform reaches a service height. Each stall comprises sliding elements interlocking with each other, the sliding of said elements being provided by means of motorization specific to each strut. This motorization means is integrated within the sliding elements themselves. In fact, during the pouring and drying phases of the concrete, the telescopic props remaining in place, the motorization means are immobilized and stopped. To lift other platforms on the same site, it is necessary to provide other motorized telescopic props that will be active while those in static recovery phase will be inactive. The performance and performance of such a device are limited and it is necessary that all telescopic props are motorized.

In addition, this device being composed of a barrel and a single coullsseau, it _is not possible to install the formwork platform at a height ergonomic of about 1 m, and to raise it to a current service height of about 2.5 m. This type of device therefore forces workers to work at height, in fatiguing and risky working positions. An identical problem arises with the device described in the document US 3,632,075 (Nuñoz).

In view of this state of affairs, the main objective of the invention is to propose a device for moving a formwork platform of the type described in the patent document. FR 2.823.521 (BOUYGUES), but with which the minimum ergonomic height of installation allows operators to properly install the formwork platform, whatever the height of service envisaged, easily and safely.

Another objective of the invention is to propose a displacement device making it possible to optimize the number of struts to be motorized on a construction site.

Disclosure of the invention.

The solution proposed by the invention is a device for moving a platform slab formwork and / or balcony, said device comprising telescopic struts on which is intended to rest said platform, said struts being configured to move said platform, without the cross, between a folded installation position and an extended position where the platform reaches a service height, said struts comprising sliding elements interlocking in one another, or on the other telescopically, the sliding of said elements being ensured by at least one drive means specific to each stay,

This device is remarkable in that each said stay is formed of at least two pairs of sliding elements, each said pair of elements. sliders with its own means of motorization. By being formed of at least two pairs of sliding elements (i.e. at least three sliding elements), each strut can be further folded so that it is now possible to install the platform formwork at an ergonomic height which is much lower than that obtained with the devices of the prior art mentioned above. In addition, the spread extent of the forestay is such that the platform can be raised to a service height that is at least twice the installation height. The use of at least two engines, especially when it comes to cylinders, reduces the size of each of said engines, and thus reduce the installation height of the platform. The work of the workers is facilitated.

For each strut, the motorization means are preferably removable and arranged outside the sliding elements of said strut. Once the telescopic struts are deployed at the service height, it is thus possible to disconnect their motorization means, to leave said struts in place during the pouring and / or drying phases of the concrete and to reuse said motorization means on other stays. The number of struts to be motorized is therefore less than with the displacement devices known from the prior art.

• d'au moins un fût en appui sur le sol et un premier coulisseau coulissant et s'emboîtant dans, ou sur, ledit fût, et d'au moins un second coulisseau coulissant et s'emboîtant dans, ou sur, ledit premier coulisseau,
• d'un premier moyen de motorisation assurant le mouvement dudit premier coulisseau par rapport audit fût, et d'un second moyen de motorisation assurant le mouvement dudit second coulisseau par rapport audit premier coulisseau,
• lesdits premier et second moyens de motorisation étant amovibles et disposes en dehors des éléments coulissants dudit étai.

Each telescopic stay is preferably equipped with:

• at least one shank resting on the ground and a first slider sliding and fitting into, or on, said shank, and at least one second slider sliding and fitting into, or on, said first slider,
• a first motorization means ensuring the movement of said first slider relative to said barrel, and a second motorization means ensuring the movement of said second slider relative to said first slider,
• said first and second motorization means being removable and disposed outside the sliding elements of said strut.

The fact of having telescopic props comprising at least three sliding elements makes it possible to reduce the installation height of the platform when said masts are in the folded position. The platform can thus be set up for operators at an ergonomic height, even if the service height is high.

Each telescopic stay may, however, include more than two sliders sliding and fitting into, or on, each other (i.e., be composed of more than three slider members). In this case, motorization means are provided which ensure the movement of a slider relative to the slider which precedes it. Thus, a slide assembly / motorization means, supports and ensures itself the movement of the upper equivalent assembly.

The sliding elements of each strut are advantageously dimensioned so that in folded position, said formwork platform can be installed at a height less than 1.80 m with respect to the ground, preferably at a height of between 1 m and 1 m. , 7 m, and in the deployed position the height of said platform can be at a service height of more than 2.40 m.

To ensure a vertical translation of the struts, without risk of twisting, the sliding elements of the struts have a section adapted to block their rotation along their axis of movement, during the sliding phases of said elements.

For safety, the one or more motorization means comprise a worm or screw / nut system configured to form a self-locking brake in case of stopping said motorization means. In these conditions, if the engine means are defective or in case of power failure, the self-locking brake prevents the telescopic props to fold and the platform to fall.

• chaque étai comprend une goupille de blocage de hauteur traversant radialement un ou plusieurs éléments coulissants dudit étai,
• la goupille de blocage repose sur une came de réglage dont le profil permet de déplacer longitudinalement ladite goupille.
• la came a un profil tel que l'angle de sa tangente au point de contact avec la goupille de blocage avec la verticale soit inférieur à l'angle de glissement du couple des matériaux came/goupille, de façon à rendre ladite came autobloquante.

In order to precisely adjust the height of each stall:

• each strut comprises a height locking pin radially traversing one or more sliding elements of said strut,
• the locking pin rests on a control cam whose profile allows to move longitudinally said pin.
• the cam has a profile such that the angle of its tangent to the point of contact with the locking pin with the vertical is less than the sliding angle of the torque of the cam / pin material, so as to make said cam self-locking.

Another aspect of the invention relates to a formwork system comprising a formwork platform and a device for moving said platform according to one of the preceding characteristics.

When the formwork platform comprises lower primary beams supporting upper secondary beams, conventing members are provided for blocking said primary and secondary beams together. These bracing members are in the form of a bar resting on two successive secondary beams, said bar being provided with a deformable fastening element, or adjustable in size, fixing under a primary beam on which rests the two said secondary beams. This allows three beams to be bonded together at the same time to maintain the platform in a parallelogram configuration and to provide an anti-tilting function of the beams. It should be noted that these bracing members are independent of the design of the telescopic props and could very well be used with other formwork devices.

In the case where the formwork platform comprises lower primary beams supporting upper secondary beams, the upper end of the telescopic props may be provided with a support head configured to support more than one line of primary beams.

• repliage des étais télescopiques de façon à ce que la plateforme de coffrage soit installée à une hauteur inférieure à 1,8 m par rapport au sol,
• construction de l'intégralité de la plateforme de coffrage lorsque les étais télescopiques sont en position repliée, la configuration de ladite plateforme correspondant, dès la position repliée, à celle de la dalle ou du balcon à coffrer,
• déployage des étais télescopiques pour hisser la plateforme de coffrage jusqu' à atteindre la hauteur de service,
• coulage du béton sur la plateforme de coffrage de façon à réaliser la dalle ou le balcon.

Yet another aspect of the invention relates to a method for forming a slab and / or a balcony using the formwork platform moving device according to one of the preceding features, said method comprising the following steps:

• folding the telescopic props so that the formwork platform is installed at a height of less than 1.8 m from the ground,
• construction of the entire formwork platform when the telescopic props are in the folded position, the configuration of said platform corresponding, from the folded position, to that of the slab or balcony to form,
• deploying the telescopic props to hoist the formwork platform to reach the service height,
• concrete pouring on the formwork platform to make the slab or balcony.

Before hoisting of the formwork platform and / or before said platform reaches the service height, it is possible to place, from said platform, safety protections on the vertical walls of the construction adjoining said platform.

• on laisse en place les étais télescopiques pour une reprise de charge statique de soutènement, les moyens de motorisation étant ou non récupérés,
• ou on démonte lesdits étais et on les remplace par d'autres moyens c'étaiement.

Preferably, during the casting and / or drying phase of the concrete:

• the telescopic props are left in place for static load-bearing support, the motorization means being recovered or not,
• where said struts are removed and replaced by other means.

After drying the concrete, the telescopic props can be folded so that the formwork platform can be dismantled at a height of less than 1.8 m from the ground.

Description of the figures.

• la figure 1 est une vue schématique montrant un agencement possible des étais télescopiques et la mise en place des poutrelles primaires et secondaires d'une plateforme de coffrage ;
• la figure 2 est une vue en coupe verticale d'un étai télescopique conforme à l'invention, ledit étal étant en position repliée;
• la figure 3 est une vue en coupe selon A-A de l'étai de la figure 2;
• la figure 4 schématise une tête de support d'un étai télescopique, dans une variante de réalisation permettant de supporter deux lignes de poutrelles primaires ;
• la figure 5 est une vue en coupe verticale de l'étai de la figure 2 en position déployée ;
• la figure 6 est une vue partielle en coupe selon B-B de l'étai de la figure 5, schématisant le dispositif de réglage à came de la hauteur dudit étai ;
• la figure 7, schématise un système de coffrage conforme à l'invention, la plateforme étant dans une position intermédiaire permettant l'installation de garde-corps en tête des murs délimitant la zone de coffrage ;
• la figure 8 schématise un organe de contreventement liant une poutrelle primaire à deux poutrelles secondaires,
• la figure 9 est une vue schématique montrant, de face, une installation dans laquelle des poutrelles joignent deux étais,
• la figure 10 est une vue de dessus de l'installation de la figure 9,
• la figure 11 est une vue agrandie de la coupe selon C-C de la figure 10.

Other advantages and characteristics of the invention will appear better on reading the description of a preferred embodiment which will follow, with reference to the accompanying drawings, carried out as indicative and non-limiting examples and in which:

• the figure 1 is a schematic view showing a possible arrangement of the telescopic props and the establishment of the primary and secondary beams of a formwork platform;
• the figure 2 is a vertical sectional view of a telescopic strut according to the invention, said stall being in the folded position;
• the figure 3 is a sectional view along AA of the forestay figure 2 ;
• the figure 4 schematizes a support head of a telescopic stay, in an alternative embodiment for supporting two rows of primary beams;
• the figure 5 is a vertical sectional view of the forestay figure 2 in the deployed position;
• the figure 6 is a partial view in section along BB of the forestay of the figure 5 schematizing the cam adjustment device of the height of said stay;
• the figure 7 , schematically a formwork system according to the invention, the platform being in an intermediate position for the installation of guardrail at the head of the walls defining the formwork area;
• the figure 8 schematizes a bracing member linking a primary beam to two secondary beams,
• the figure 9 is a schematic view showing, from the front, an installation in which beams join two struts,
• the figure 10 is a top view of the installation of the figure 9 ,
• the figure 11 is an enlarged view of the section according to CC of the figure 10 .

Embodiments of the invention

By referring to the figure 1 , the lifting device object of the invention comprises a series of telescopic props 1 which are generally arranged in a lower cell where a slab or a balcony must be cast. The struts 1 are independent of each other and rest on the floor of this cell.

The struts 1 make it possible to move a formwork platform, without crossing it, between a folded installation position and an extended position where said platform reaches a service height. The number of struts 1 associated with each formwork platform is scalable according to the surface of the latter. In practice, this number can vary from four to ten or more.

The formwork platform is standard, of the type usually used on construction sites. Indeed, the device of the invention adapts to any type of formwork platform market, and is placed below the structure of said platform. It is not a specific platform. By referring to figures 1 and 7 , the structure of the platform may consist of primary beams 30 for supporting the entire load and secondary beams 31 resting on said primary beams. The primary beams 30 are for example metal beams having a T-section 31. The secondary beams 31 are for example conventional beams of wood or metal, T-shaped, square or rectangular. According to the usual practice of the workers, the secondary beams 31 are arranged perpendicular to the primary beams 30.

The upper end of the struts 1 is provided with a support head 33 on which rests the primary beams 30, without mechanical connection. The support heads 33 may, however, comprise at their end a vertical return 331 making it possible to block the lateral movement of the pimetral beams 30. In an alternative embodiment, the support heads 33 may comprise a recess having a shape complementary to the primary beams 30 so as to to maintain in position these. The skilled person may also provide any locking means in position of the primary beams 30, for example straps, if it deems necessary. The support heads 33 may be removable (they are typically placed on the upper end of the last sliding element) and interchangeable depending on the configuration of the formwork platform to be moved (for example if said platform comprises beams, or beams + panels or panels alone). Their width is adapted so as to offer an optimal spacing ratio of primary beams 30 and they allow to carry said beams equidistant from the vertical axis of the stall. Advantageously, and as shown on the figure 4 the support heads 33 may be configured to support more than one line of primary beams 30 (two, three or four rows of beams).

The secondary beams 31 may simply be placed on the primary beams 30 with or without a mechanical connection. Referring to the figure 7 plywood 32 or panels, forming the formwork skin, are then positioned on the secondary beams 31. In principle, the plywood 32 are placed on the secondary beams 31, with or without mechanical connection. The primary and secondary beams 30 and 31 as well as the plywood 32 are standard formwork elements set up in the traditional way. The platform could however consist of formwork panels, combined or not with beams.

In the case of balcony construction or in the case of construction between poles - and thus with significant lateral movement possibilities - it is possible to resort to bracing members between the legs of the telescopic props 1. These bracing members may for example consist of link braces, of the type that are usually used for the bracing of shoring towers or scaffolding.

Another solution is to break up the formwork platform by using locking members inserted between the primary beams and the secondary beams, or between the primary beams and the formwork panels, or between the formwork panels between them. Such a bracing member is schematized on the figure 8 and has the reference 300. It is in the form of a bar 301 bearing on two secondary beams 31 successive, said bar being provided with a deformable fastening element 302, or adjustable in size, being fixed under a beam primary 31 on which rests the two said secondary beams. With only one bracing member 300, it is possible to connect three beams to each other, which increases the rigidity of the shuttering platform in the horizontal plane and ensures anti-tilting of the connected beams. The bracing member 300 is preferably made of metal. The bar 301 may have a rectangular, square, oval or round section. The fastening element 302 may be in the form of a folded metal blade or a bow, fixed perpendicular to the bar 301. Front view, the assembly has substantially the shape of a T.

The bracing members 300 can be assembled from the construction of the ergonomically height formwork platform for a worker (about 1m), or added after hoisting the platform to a height accessible by a worker (about 2 m), without the need for a scaffolding or ladder, and for higher heights, using a pole.

The bracing members 300 may be provided with a strap, chain, cable or any other link during, fixed on the fastening element 302 or on the bar 301. This link during, when it is stretched, makes it possible to plate the formwork platform to the ground or against an adjacent vertical wall or against a pole or forestay. It is also possible to install on certain bracing members, straps, carabiners, or any other equivalent attachment means for hanging a stop-fall net or sprocket. It is necessary in this case to provide a significant resistance of the attachment means to resume the dynamic forces induced by the fall of a worker or heavy equipment.

• une fonction de liaison empêchant tout mouvement (déplacement latéral, soulèvement, basculement, ...) des poutrelles secondaires par rapport aux poutrelles primaires. En assurant un blocage des angles orthogonaux des parallélogrammes formés par l'agencement des poutrelles primaires et secondaires, on assure un anti-soulèvement desdites poutrelles secondaires par rapport aux dites poutrelles primaires et un anti-glissement latéral desdites poutrelles secondaires entre-elles. Il en est de même pour la liaison éventuelle entre deux panneaux de coffrage et une poutrelle primaire.
• a une fonction du placage de la plateforme de coffrage par tension des liens pendants, afin d'assurer un anti-dévers.
• une fonction de support d'attache d'un filet stoppe-chute ou pare-objet.

Such a bracing member 300 thus provides for itself a triple function,

• a binding function preventing any movement (lateral displacement, lifting, tilting, ...) of the secondary beams relative to the primary beams. By blocking the orthogonal angles of the parallelograms formed by the arrangement of the primary and secondary beams, it ensures an anti-lifting of said secondary beams relative to said primary beams and a lateral anti-slip of said secondary beams between them. It is the same for the possible connection between two shuttering panels and a primary beam.
• has a function of the plating of the formwork platform by tension of the hanging links, to ensure anti-roll.
• a support function for attaching a stop-and-fall net.

By referring to Figures 9 and 10 , a primary junction beam 34 can be arranged between two struts 1. Two additional primary beams 30 overhang cantilevered on each side of the struts 1. The adjustment of the total length is adjustable by changing the length of overlap between the two beams 30 and the junction beam 31. Once the length is defined, these three beams are then bonded, in order to compensate (partially) the cantilever overflowing beams 30. The connection is made by means of a holding device 340 which clamps and locks the beams together. An exemplary embodiment of this holding device 340 is schematized on the figure 11 . It comprises a fixed jaw 341 and a movable jaw 342, both connected to a threaded tie rod 343. The jaws 341, 342 are intended to grip the "overhanging" joists 30. Each jaw 341, 342 is advantageously made from a metal plate shaped so as to maintain the "overhanging" beams 30 in position and block their lateral movement. The fixed jaw 341 is attached to one end of the slide, for example by welding. The movable jaw 342 comprises guides 3420 in which the threaded tie rod 343 slides. A clamping member 344, of the nut type, makes it possible to clamp the movable jaw 342 against the "overflowing" beam 30 on which it bears. Such binding of beams also fulfills a role of anfi-tilting primary primary beams 30.

The Figures 2, 3 and 5 schematically a telescopic stay 1 according to the invention. These struts 1 comprise sliding elements which fit into one another or on the other telescopically. According to the invention, each strut 1 is formed of at least two pairs of sliding elements 10, 11, 12 (that is to say at least three sliding elements), each said pair of sliding elements having its own means of motorization M1, M2. Their sliding movement is therefore provided by at least two motorization means M1, M2 specific to each stall. In practice, each strut 1 comprises at least one drum 10 resting on the ground, a first slider 11 sliding and fitting into or on said barrel 10, and advantageously at least one second slider 12 sliding and interlocking in or on said first slider 11. However, a greater or smaller number of sliders can be provided according to the heights desired in the deployed position and in the folded position, it being understood that at the most there are sliding elements, at most the height reached in the folded position is low. The sliding elements 10, 11, 12 are advantageously dimensioned so that in the folded position, the formwork platform can be installed at a height of less than 1.80 m with respect to the ground, preferably a height of between 1 m and 1.7 m. Each sliding element 10, 11, 12 may therefore have a length of between 1 m and 1.7 m, preferably between 1 m and 1.5 m. In this case, with struts 1 comprising three sliding elements 10, 11, 12, the formwork platform can be located at a service height of more than 2.40 m, typically between 3 m and 5.1 m.

It is thus possible to lower the whole of the formwork platform, during stripping operations, and bring it back to an ergonomic height for a man (approximately 1 meter) in order to disassemble it safely and optimize the comfort of job.

The barrel 10 can be provided with a base or a tripod ensuring its good stability on the lower floor. The base can incorporate retractable wheels so that the strut 1 can be easily moved from one formwork cell to another without lifting means.

The sliding elements 10, 11, 12 are preferably made of steel, but other materials such as plastics having good mechanical strengths, especially compression, can be envisaged. Referring more specifically to the figure 3 , the sliding elements 10, 11, 12 are square section elements. A rectangular, polygonal, oval, oblong, U-shaped section, the use of a guide groove along said sliding elements for a round section, or other, could also be provided in an equivalent way. Because of the thrust forces, this type of section makes it possible to block the rotation of the sliding elements 10, 11, 12 along their axis of displacement and during their sliding phases.

Preferably, the drive means M1, M2 of each strut 1, are removable and arranged outside the sliding elements 10, 11, 12 of said strut. By referring to Figures 2, 3 and 5 when the struts 1 comprise three sliding elements, each said strut is provided with a first motorization means M1 ensuring the sliding movement of the first slider 11 relative to the shaft 10 and a second motorization means M2 ensuring the sliding of the second slide 12 relative to said first slide. Thus, each pair of sliding elements: barrel / first slide and first slide / second slide has its own motor. These motorization means M1, M2 are preferably removable and arranged outside the sliding elements 10, 11, 12. In the case where there is a shaft and more than two slides, several motorization means ensure the sliding of a slide by compared to the slider that precedes it. In this way, each pair of sliding elements has its own motorization.

The use of removable motor means is particularly advantageous because many opportunities are offered to workers. Indeed, the struts 1 can remain in place with their means (s) of motorization, in static function support load recovery, during the casting phase and / or drying of the concrete slab. The struts 1 can also be partially disabled by disassembly of their means (s) of motorization and remain in support of static recovery during the operations of reinforcement and concreting concrete slab or balcony. They can also be completely disassembled and be replaced during this phase of recovery of static load by conventional props open to the necessary height of service.

The drive means M1, M2 may consist of electric cylinders, mechanical, or hydraulic racks, etc. It is preferred to use electric worm screw jacks which are either connected to a current source available on the site, or equipped with their own power supply (battery, ...). By referring more specifically to Figures 2 and 3 , the barrel 10 comprises a base 100 on which rests the lower end of the first motorization means M1, which is here a jack. The upper end of this first jack bears against a protruding edge 110 of the first slider 11. In practice, this edge is located at the upper end of the first slider 11, opposite the base 100. Similarly, , the first slider 11 is provided with a projecting element forming a base 110 on which rests the second motorization means M2, which is again a cylinder. This base 110 is disposed outside the shaft 10. The upper end of the second cylinder bears against a projecting edge 120 of the second slide 12. In practice, this edge is located at the upper end of the second slide 12, opposite the base 110.

The lower and upper ends of the motorization means M1, M2 are advantageously fixed respectively on the bases or against the edges of the sliding elements 10, 11, 12, by means of easily removable connection, for example simple screw connections.

When the first jack deploys, its upper end pushes the edge 110 upwards and thus moves the first slide 11 upwards. By moving thus, the first slide 11 will drive the second jack upwards and thus also the second one. slide. However, the relative movement of the latter relative to the first slider 1 remains at this stage zero. Only when the second cylinder deploys, its upper end pushes up the edge 120 and moves up the second slide 12. And so on when other slides are used on the same stall. When the cylinders fold back, we observe a reverse movement.

To ensure that all telescopic props 1 up and down at the same time, it is possible to provide linear position sensors capable of giving at each moment the vertical position of each of said struts and / or each of their sliding elements. All the sensors are rellés with a programmable automaton, or an electronic central unit, making it possible to analyze the position of each support element 2 and to control the various means of motorization accordingly. This central control unit can enslave the entire network of telescopic props 1 and make them evolve in a synchronized manner, with the same movement and the same speed, with the minimum difference, whatever the load applied. In this way, the raising and lowering of the formwork platform can be controlled automatically by a single operator, via a single control box connected to the central control unit,

It may be advantageous to provide up / down limit switches so as to ensure that the motorization means automatically stop and / or move to the disengaged position when the struts are fully deployed or folded. These end-of-travel detectors are advantageously associated with each sliding element 10, 11, 12.

The motorization means M1, M2 advantageously comprise a worm or screw / nut system, for example of the type that are usually used in worm screw jacks. This system is configured to form a self-locking brake preventing the struts 1de to fold and the platform to fall if the drive means are defective or in case of power failure. To do this, the worm may have a tapered thread forming a self-locking brake and / or a low pitch (lower than the coefficient of friction screw / nut) and / or threads inclined by 2 ° to 5 °, etc. The drive means M1, M2 may also include any additional element or safety element (for example a safety nut).

Since the drive means M1, M2 can be removable, it is advantageous to adjust the height of the struts 1 and to lock in position the sliding elements 10, 11, 12 independently of said means engine, when said struts are in the deployed position of service and that they are not replaced by conventional props during the pouring and drying phases of the concrete. By referring to the figure 5 two sets of adjusting pins 41, 42 are provided.

A first pin 41 is used for a rough adjustment of the height. This first pin 41 passes radially through two sliding elements of a stall 1 to block their respective movements. On the figure 5 , the first pin 41 blocks the second slider 12 relative to the first slider 11 but could be used to block said first slider relative to the shaft 1, or other sliding elements. In practice, a series of housings 410 is formed in the sliding elements to be locked and into which the first pin 41 is inserted. The precision of the adjustment is therefore equal to the distance separating two housings 410.

A second pin 42 is used for a finer adjustment of the height. This second pin 42 also crosses radially one or more sliding elements of a strut 1 to block their respective movement. On the figure 5 the second pin 41 blocks the first slider 11 relative to the barrel 10, but provision could be made to use it to lock the second slider 12 with respect to said first slider or other sliding elements. In practice, a series of housings 420 is formed in the sliding elements to be locked and in which the second pin 42 is introduced. It is important, depending on the configuration of the floor on which the struts 1 and / or depending on the configuration of the slab or balcony to achieve, to be able to accurately adjust the deployment height of the props 1, this height may vary from one strut to another. To do this, one of the housings of at least one of the sliding elements is configured to allow a longitudinal displacement of the second pin 42. This displacement induces a longitudinal displacement of one of said elements sliding. In the example of the figure 5 , the barrel 10 comprises a housing 421 allowing such a displacement. This is for example an oblong hole, or a groove, oriented in the direction of the length of the barrel 10 and made at the upper end of said barrel. The second pin 42 rests on an adjusting cam 43 whose profile makes it possible to move said pin longitudinally in the housing 421. This cam 43, whose profile is schematized on the figure 6 , rotatably mounted on the sliding element which comprises the housing 421. By rotating the cam 4, its profile will move the second pin 42 in the housing 421 and thus move up or down the first slide 11 (or another sliding element in which said pin would be housed). Once the desired height is reached, the cam 43 is locked in position by a nut 430. figure 6 the arrow F schematizes the force of the second pin 42 on the cam 43 and the arrow M schematizes the resulting torque. The profile of the cam 43 is such that the angle "α" of its tangent to the point of contact with the second pin 42 with the vertical is less than the angle "φ" slip of the torque of the cam / pin material. This ensures that, in case of tendency to slip cam / pin, the cam 43 has a tendency to rotate in the sense that it will tighten the nut 430 which immobilizes it, and thus make it self-locking.

The device object of the invention makes it possible to set up the formwork platform in a very simple and perfectly secure way for the workers. This implementation will now be described in more detail.

Previously, the struts 1 are available in the cell where the slab is to be made, or outside for the realization of a balcony. The number and the distribution of the struts 1 comply with the usual rules of formwork, according to the weight of the slab or balcony concrete, the bending strength of the primary and secondary beams 31 and the maximum deflection admitted to the construction market.

The struts 1 are folded so that the formwork platform can be installed at an ergonomic height for the man, advantageously to a height less than 1.8 m from the ground, preferably at a height of between about 80 cm and about 1.5 m, preferably a height of about 1 m.

The workers can then easily build the entire formwork platform (possibly excluding some finishing operations such as the lateral cut-outs of the formwork skin and the wedging), by perfectly adapting the structure of the latter to the configuration of the slab or slab. balcony to form. The primary beams 30 are first laid on the support heads 33, then the secondary beams 31 are placed on said primary beams, and optionally bonded by the bracing members 300. The plywoods 32 forming the formwork skin can then be positioned on the secondary beams 31 without leaving any free linear hopper to the right of the struts 1, the latter not passing through the formwork platform in the folded position.

Once the formwork platform is assembled, the struts 1 are deployed in one or more steps to hoist said platform to reach the service height, that is to say at the height of the slab or balcony to achieve. In the case where the drive means of the struts are synchronized, only one worker is necessary for this operation. It is then enough to pour the concrete on the platform of formwork so as to realize the slab and / or the balcony. Before pouring, it will be possible beforehand to carry out peripheral finishing operations of the formwork platform, such as reinforcement and installation of accessories for the slab or balcony.

Before hoisting of the formwork platform and / or before it reaches the service height, it is possible to place, from said platform, safety protections on the vertical walls of the construction adjoining said platform. This intermediate step is schematized on the figure 7 . It allows workers to come place security protections 5 or guardrails head vertical walls V and / or posts adjacent to the formwork platform. The installation takes place in total safety, because the platform is not only covered entirely in plywood 32, without any hopper open, but it is still held at this stage not high, or partially high, between the walls V and / or vertical posts forming a concrete safety wall. The drive means M1, M2 of the struts 1 are in this case sized to withstand the additional load caused by the carrying of workers and safety barriers. In addition, since the drive means M1, M2 incorporate a self-locking brake, ensures blocking the platform in position, even intermediate, without manual intervention of the worker and without having to use the pinning system. The worker who is on the formwork platform is therefore in total safety.

Preferably, during the pouring and drying phase of the concrete, the workers leave in place the struts 1 for a static loading support, the motorization means M1, M2 being recovered or not for use on other struts or they disassemble said struts and replace them with other conventional shoring means.

After the concrete has dried, the struts 1 can be folded so that the formwork platform can be dismantled at a height less than 1.8 m from the ground. In practice, the worker will be able to lower the platform in one or more steps to the initial folded installation position, ergonomically height for a man, in order to dismount said platform safely and comfort. An intermediate step of stopping the descent makes it possible to be able to take off, by manual intervention, the plywoods 32 of the formwork skin that would have remained stuck to the concrete and make them fall in contact with the secondary beams 31 or the formwork panels.

• une fonction de mouvement ascendant et descendant de la plateforme de coffrage avec une capacité de déplacement importante puisqu'elle autorise de construire ou démonter ladite plateforme à une hauteur ergonomique pour un homme et permet de la positionner à la hauteur désirée de construction de la dalle ou du balcon,
• a une fonction de plateforme de travail conforme en tous points à la réglementation sécurité passive des ouvriers, complètement fermée, sans trémie ouverte, pour la mise en place des barrières ou garde-corps de sécurité en tête des murs et poteaux périphériques,
• et une fonction statique de reprise de charge du poids propre de la dalle ou du balcon, comme un étai classique.

The system and device that is the subject of the invention provides a triple function:

• a function of upward and downward movement of the formwork platform with a large displacement capacity since it allows to build or dismount said platform at a height ergonomic for a man and allows to position it at the desired height of construction of the slab or balcony,
• has a work platform function fully compliant with the passive safety regulations for workers, completely closed, without open hopper, for the installation of safety barriers or guardrails at the top of walls and peripheral posts,
• and a static load-recovery function of the self-weight of the slab or balcony, like a conventional strut.

Claims (15)

Device for moving a slab and / or balcony formwork platform, said device comprising telescopic struts (1) on which said platform is intended to rest, said struts being configured to move said platform, without passing through it, between a folded position installation and an extended position where the platform reaches a service height, said struts comprising sliding elements (10, 11, 12) interlocking in, or on, the other telescopically, the sliding of said elements being provided by at least one drive means (M1, M2) specific to each strut, characterized in that each said strut is formed of at least two pairs of sliding elements (10, 11, 12), each said pair sliding elements having its own means of motorization (M1, M2). Device according to claim 1, wherein for each strut, the drive means (M1, M2) are removable and disposed outside the sliding elements (10, 11,12) of said strut. Device according to one of the preceding claims, wherein each telescopic stay (1) is equipped with: • at least one barrel (10) resting on the ground and a first slider (11) sliding and fitting into, or on, said barrel, and at least one second slider (12) sliding and s' nesting in, or on, said first slide, A first motorization means (M1) ensuring the movement of said first slide relative to said shaft, and a second motorization means (M2) ensure the movement of said second slide relative to said first slide, Said first and second motorization means being removable and arranged outside the sliding elements (10, 11, 12) of said strut. Device according to claim 3, wherein each telescopic stay (1) comprises: • more than two slides sliding and fitting one into, or on, the others, • Motorization means ensuring the movement of a slider relative to the slider which precedes. Device according to one of the preceding claims, wherein each telescopic stay (1) is equipped with: • at least one barrel (10) resting on the ground and a first slider (11) sliding and fitting into, or on, said barrel, and at least one second slider (12) sliding and s' nesting in, or on, said first slide, The barrel (10) comprises a base (100) on which rests the lower end of a first cylinder (M1), the upper end of said first cylinder bearing against a projecting edge (110) of the first slide (11); ). Said first slider (11) is provided with a projecting element forming a base (110) on which a second cylinder (M2) rests, the upper end of said second cylinder bearing against a projecting edge (120) of the second slide (12). Device according to one of the preceding claims, wherein the sliding elements (10, 11, 12) of each strut (1) are dimensioned so that in the folded position, said formwork platform can be installed at a lower height at 1.80 m from the ground, preferably at a height of between 1 m and 1.7 m, and in deployed position the height of said platform can be at a service height of more than 2.40 m. Device according to one of the preceding claims, wherein the drive means (M1, M2) comprise a worm or screw / nut system configured to form a self-locking brake in case of stopping said drive means. Device according to one of the preceding claims, in which: Each strut (1) comprises a locking pin (42) radially crossing one or more sliding elements (11, 12) of said strut, Said locking pin rests on a setting cam (43) whose profile makes it possible to move said pin longitudinally, Said cam has a profile such that the angle (α) of its tangent at the point of contact with said locking pin with the vertical is less than the slip angle (φ) of the torque of the cam / pin material, so to make said self-locking cam. Slab and / or balcony formwork system comprising: • a formwork platform, A device for moving said formwork platform, characterized in that said device is in accordance with one of the preceding claims. Formwork system according to claim 9, wherein: The formwork platform comprises lower primary beams (30) supporting upper secondary beams (31), Bracing members (300) block said primary and secondary beams together, said members being in the form of a support bar (301) on two said secondary beams; successive, said bar being provided with a deformable fastening element (302), or adjustable in size, fixing under one of said primary beams on which rests the two said secondary beams. Shuttering system according to one of Claims 9 or 10, in which: The formwork platform comprises lower primary beams (30) supporting upper secondary beams (31), The upper end of the telescopic props (1) is provided with a support head (33) configured to support more than one line of primary beams. Shuttering system according to one of Claims 10 or 11, in which: • the formwork platform comprises a primary junction beam (34) disposed between two struts (1), two additional primary beams (30) overflowing cantilevered on each side of said struts, • a holding device (340) links the primary junction beam (34) and the overflowing primary beams (30). A method for forming a slab and / or a balcony using the device according to one of claims 1 to 8, said method comprising the following steps: • folding the telescopic props (1) so that the formwork platform is installed at a height of less than 1.8 m from the ground, • construction of the entire formwork platform when the telescopic props (1) are in the folded position, the configuration of said platform corresponding, from the folded position, to that of the slab or balcony to form, • Deployment of the telescopic props (1) to hoist the formwork platform until reaching the service height, • pouring concrete on the formwork platform to make the slab or balcony. A method according to claim 13, wherein before hoisting of the formwork platform and / or before said platform reaches the service height, safety protections (5) are placed on said vertical walls from said formwork platform (5) ( V) of the construction adjoining said platform. Method according to one of claims 13 or 14, wherein during the pouring and / or drying phase of the concrete: • the telescopic stalls (1) are left in place for static load-bearing support, the motorization means (M1, M2) being recovered or not, Or dismounting said struts and replacing them with other means of shoring.

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