FR2857044A1 - Formwork for forming reentrant, has sealing part whose mechanical resistance to impact under action of a hammer and/or removable character permits to resist forty form removal operations - Google Patents

Abstract

The formwork has a reentrant case (5) with a support side having a magnetic unit for fixation of the case on a metallic panel. A sealing part (6) is located opposite to the support side of the reentrant case. The sealing parts mechanical resistance to an impact under the action of a hammer permits to resist forty form removal operations. The resistance to the impact is about 500 joules.

Description

2857044 1

  FORMING ELEMENT FOR FORMING A SMALL-SIZE RESERVATION IN A CONCRETE WORK AND FORMWORK ASSEMBLY COMPRISING A PLURALITY OF SUCH ELEMENTS

  PERMITTING A COMBINATION WITH A REINFORCEMENT

  The present invention relates to the field of the building and more particularly the realization of concrete structure in which it is necessary to form reservations for the passage of equipment or accessories. It relates more particularly to a shuttering element lo designed to form a small-sized reservation across the entire width of a structure including concrete sail, and a formwork assembly comprising a plurality of such formwork elements allowing a combination with a frame, including a welded mesh.

  In the case of large-scale reservations, prefabricated and reusable mannequins attached to the metal forms of the formwork are used, in particular by magnetic shoes.

  In the case of small or medium-sized reservations, booking elements, also called reservation boxes, are used, which are most often made directly on the site from wood or polystyrene. These are booking elements that have the major disadvantage of not being reusable, which monopolize labor on the site and which give relatively rough reservations that may require patching or resumption. Moreover when they are wood, the formwork is difficult because of the swelling of the wood during concreting.

  It has already been proposed to overcome these disadvantages by proposing reservation elements that can be used several times while limiting the difficulties of stripping.

  In particular the document FR2.635.803 relates to a modular formwork assembly for making a reservation in a concrete veil, which assembly comprises a main element and auxiliary elements 2857044 2 which are equipped with assembly means intended to cooperate to form the booking. The main element, like each of the auxiliary elements, have a bearing face having housings receiving magnetic elements for fixing the element on its bearing surface against the metal shuttering formwork.

  In this document, it is expected that the main element and the auxiliary elements as well as the various assembly accessories such as fasteners, are preferably made of a synthetic material or having a certain elasticity, neoprene or other , 1 o to facilitate the establishment and stripping, without damaging the shape of the room to allow its reuse without the fact that in the reservation thus made, it is necessary to proceed to the work of récréageage.

  In addition, the main element and the auxiliary elements can be made solid or possibly hollow being, in this case, defined only by the walls. In this latter variant, the hollow element may optionally be filled with a material such as a synthetic foam to reinforce it.

  According to the applicant, despite all the advantages it brings, the reservation element described by the document FR.2.635.803 does not make it possible to obtain that said element can be reused a very large number of times, in particular a number of times equal to or greater than forty.

  It is the object of the present invention to provide a reservation element that overcomes this disadvantage.

  In known manner, it is a formwork element for forming a small-sized reservation across the entire width of a concrete structure hereinafter referred to as a reservation element -, comprising a plastic box having a face bearing support equipped with magnetic means for its attachment to a metal formwork formwork, hereinafter called reservation box.

  Typically, according to the present invention, the reservation element comprises a striking piece, opposite to the bearing face of the reservation box whose mechanical resistance to impact under the action of a hammer and / or the removable character, allows the reservation element to withstand at least forty stripping operations.

  The applicant has indeed found that it is the degradation of the rear part of the reservation element which limits the capacity of reuse of said element. The rear part is the part of the reservation element which is opposed to the front face or bearing face, comprising the magnetic means, of the reservation box. This degradation of the rear part is caused by the impacts of the hammer blows of the user, 1 o which blows are necessary to allow the ejection of the reservation element outside the partially consolidated concrete structure, during the Formwork is usually done twelve hours after pouring.

  In a first embodiment, the striking piece is constituted by the rear face of the reservation box which is opposite to the bearing face, and which is called in this case striking face. This striking face then has an impact resistance of at least 500 joules.

  Preferably, the reservation element is a hollow plastic box, of low density, whose striking face has a thickness greater than the other faces. Advantageously this box is obtained by roto-molding.

  In a second embodiment, the striking piece is an interchangeable piece, which is attached to the rear face of the plastic reservation box.

  This interchangeable piece can be a piece of wood, or a piece of high density plastic material.

  This interchangeable piece can be reported by screwing on the rear face of the reservation box with threaded inserts.

  The reservation element is intended to form a reservation over the entire thickness of the concrete web. It is known that the magnetized means 3o equipping the support face of the reservation box make it possible to ensure the positioning of said box on the front wall of the formwork. However, the magnetization force is generally not sufficient to ensure retention of the reservation element during the pouring of the concrete between the two panels. To overcome this difficulty, it is known, and in particular by the document FR.2.635.803, to provide a fastening element, integrated in the reservation box, which has a length slightly greater than the thickness of the web, so as to that said fixing element is compressed during the clamping of the formwork so as to obtain the blocking of the reservation element not only by the magnetic hooking on the front formwork but also by the 1 o compression of the element fastening, between the front and the back banche.

  In the context of the present invention, according to an alternative embodiment, the blocking by compression of the reservation element is obtained thanks to the implementation of a compressible material, which is arranged between the reservation box and the plate of hit.

  According to another variant, in which the bearing face of the reservation box comprises housings for the magnetized means, said compressible material is disposed between the magnetized means and the bottom of said housing.

  In another variant embodiment, the compression locking of the reservation element is obtained by virtue of the elastic deformation capacity of the side wall or walls of the reservation box under the effect of the pressure. There are sidewalls when the cross section of the reservation box has a polygonal peripheral contour. There is a side wall when said peripheral contour is continuous, including a circle or an oval.

  Preferably, in the latter case, the side wall or some of the side walls of the reservation box has an oblique, convergent inclination, from the bearing face to the rear face, said inclination having a convex curvature. Certainly the document FR.2. 635.803 provides that certain sides of the main element or auxiliary reservation elements can be angled, with a convergent inclination from the front to the rear face, so as to facilitate the stripping. It is also provided in this same document that some faces may have a curvature. However, in the latter case, on the one hand, there are two sides that are not angled and on the other hand it is a concave curvature whose interest is to ensure a good contact between two elements. adjacent to prevent penetration of liquid concrete in the gap between said elements once they are assembled.

  In this case, the convex curvature of the side wall or walls is intended to ensure that the elastic deformation of said wall, caused during the clamping of the formwork, is also convex and not concave. Thus, during the removal of the panels at the time of stripping, the plastic material constituting the reservation box tends to return to its original position, which ensures a certain detachment or at least a decrease in adhesion between the concrete and the reservation box, which correspondingly decreases the impact required for stripping and consequently increases the reusability of the reservation element.

  It is another object of the invention to provide a formwork assembly which comprises, in combination, a plurality of reservation elements in particular as characterized above, and an armature. More specifically, the formwork assembly comprises a plurality of reservation elements whose one or more side walls of the reservation box have a convergent oblique inclination, from the bearing face to the rear face. In addition, the support faces of the different reservation elements are adjacent to each other. In this way, are delimited in the intervals between the adjacent side walls of the free spaces for the placement of the frame inside the formwork, at least in the area delimited by the reservation elements.

  Thus, the juxtaposition of the small-size reservation elements according to the invention makes it possible to obtain a reservation of average dimension while at the same time making it possible to integrate a reinforcement, in particular but not exclusively a welded mesh, into the formwork in the booking.

  As a welded mesh, its positioning is usually in the middle part of the formwork in a plane parallel to the banches. So that, in this median part, the free space between the reservation elements can accommodate a welded mesh, it is necessary to determine on the one hand the angle of inclination of the side wall or walls and on the other hand the diameter d of each wire welded mesh, depending on the width L of the formwork. In particular, the tangent must be at least slightly greater than the ratio d / L.

  The present invention will be better understood on reading the description which will be made of exemplary embodiments of small size reservation elements, illustrated by the appended drawing in which: FIG. 1 is a schematic perspective view of a 2 is a diagrammatic sectional view of the reservation element of FIG. 1; FIGS. 3 and 4 are partial enlarged views of a reservation element at the level of FIG. striking plate (FIG. 3) and at the level of the magnetized chip (FIG. 4), with the implementation of a compressible material, FIG. 5 is a schematic representation in section of a reservation element of FIG. FIG. 6 is a schematic representation in section of a plurality of reservation elements of FIG. 1 positioned in a formwork, in combination with a welded mesh and FIG. 7 is a representation in section along the plane VII-VII of FIG. 6.

  The reservation element which will be described below and which is illustrated in the accompanying figures has a rectangular cross section. However, this is not exclusive of the present invention, this section could be square, polygonal, circular or even oval.

  This reservation element 1 comprises a bearing face 2, equipped with magnetized pellets 3, intended for the at least temporary fixing of the reservation element 1 on a metal section 4 of the formwork.

  This bearing face 2 constitutes the front face of a plastic box 5 which, in the example illustrated, has the shape of a parallelepiped of rectangular section. The side walls 5a of this box 5 are inclined from the front to the back, as is clear from the figures.

  The reservation element 1 is distinguished more particularly by a striking piece, which is opposite the bearing face 2 and which, in the example shown, is a part 6 attached to the rear face 7 of the plastic box 5 which is opposed to the bearing face 2.

  It is this striking piece that is subjected to the impacts of the hammer 15 during stripping operations.

  As regards a striking piece 6 reported, it is fixed, for example by screwing, on the rear face 7 of the reservation box 5. Preferably in this case, there are provided as many threaded inserts as screws, in said reservation box 5, at the rear face 7. In the case of a molded plastic box, each threaded insert 8 is obtained during the actual molding of the box 5.

  The striking piece 6, reported, can be replaced in case of alteration under the impact of the hammer, by simply screwing / unscrewing. It is therefore sufficient to have on site a certain amount of replacement striking pieces.

  This striking piece 6 can be made of wood, of high density plastic material, possibly made of natural or synthetic rubber.

  In another variant, not shown, the striking piece is constituted by the rear face of the reservation box, said striking face.

  3o in this case the impact strength of the impactor is determined so that it withstands hammer impacts for at least 2857044 8 forty stripping operations under normal conditions, this resistance being at least 500 joules. In an exemplary embodiment, the hollow plastic box is obtained by roto-molding high density polyethylene, the thickness of the striking face being of the order of 10 mm while the thickness of the side walls is the order of 5-6 mm.

  Figure 5 illustrates the positioning of a reservation element 1 in a formwork.

  The metal formwork before formwork 4 being set up on the site, the operator just apply the support surface 2 of the reservation element 1 on said metal tray 4 in the location provided for the reservation. The rear metal panel is then placed at a distance from the front panel that corresponds to the thickness of the concrete web that is desired. The concrete 10 is then poured between the two panels 4, 9 and thus around the reservation element 1. After a certain setting time of the concrete, generally of the order of twelve hours, the two strips 4, 9 and the formwork of the reservation element 1. This formwork is obtained by striking, with the aid of a hammer, on the striking part 6, with sufficient force to pull out the element of reservation 1 of the concrete block 10 surrounding it. It is to facilitate this ejection that the side walls 5a of the box 5 are obliquely inclined convergently towards the rear face 7.

  When pouring the concrete, the reservation element 1 could possibly move if the locking in position of said element between the two panels 4, 9 was not sufficient. To complete this blocking, it is known to perform a certain compression of a fastener between the two panels 4, 9, during the clamping of the formwork. In the case of the present invention, this compression is obtained either by the implementation of a compressible material, in the reservation element itself, or by the deformation of the reservation box.

  In a first variant embodiment, illustrated in FIG. 3, the compressible material 11, for example made of natural or synthetic rubber, is disposed between the striking piece 6 and the rear face 7 of the reservation box 5, being maintained between the two elements, in particular thanks to screws 12.

  In a second variant embodiment, illustrated in FIG. 4, the compressible material 13 is disposed in the bottom 14a of a housing 14 in which the magnetized chip 15 is placed, said housing 14 being formed in the bearing face 2 of the booking box 5.

  More specifically, the magnetized chip 15 has a displacement capacity inside the housing 14 thanks to the compressibility of the material 13. In the normal position, the material 13 is not compressed, the chip 15 protrudes outside the housing 14. When the reservation element is put in place and when the clamping between the two panels 4, 9 intervenes, the magnetized chip 15 moves towards the interior of the housing 14 under the effect of the compression of the material 13. In the example illustrated in FIG. 4, the magnetized chip 15 and the compressible material 13 both comprise a through-hole 16, 16 'for the passage of a screw 17, cooperating with a threaded recess 18 provided in the face of FIG. support 2. The through hole 16 of the pellet 15 is shaped so that the head 17a of the screw 17 penetrates inside the pellet 15 over a distance d which corresponds to the maximum displacement capacity of the pellet due to the compres material 13 when clamping the formwork. FIG. 4 shows the positioning of the magnetized chip 15 protruding out of the housing 14 over the distance d. When clamping the formwork, the pressure exerted (arrow F) by the front panel on the magnetized chip pushes it towards the inside of the housing 14, which is made possible by the compressibility of the material 15 and the possibility of sliding of the material 15 and the pellet 15 along the screw 17. This embodiment is of course not exclusive to the present invention.

  The compression of the reservation element, during the clamping of the formwork, can also be obtained through the deformation of the side wall or walls of the reservation box. In this case, it is preferable for the one or more walls to have a slight convex curvature, which curvature will be accentuated during compression. When removing one of the panels, compression ceases and the plastic material constituting the reservation box tends to return to the initial position, which tends to separate the sidewall of the concrete and to facilitate the stripping of the element of booking.

  The reservation element of the present invention is relatively light and very easy to handle. For example, for an average dimension of 15 × 20 × 16 cm, with a rotomolded polyethylene reservation box, either with a striking face or with a striking piece, the reservation element is of the order of 2 kg, 15 × 20 cm being the dimensions of the bearing face 2 and 16 cm being the height of the element between the bearing face 2 and the face or the striking piece.

  FIGS. 6 and 7 show an example of a medium-sized reservation, using nine reservation elements 1 as described above, with a coin punch. But it can also act as reservation elements without striking piece, as long as the side wall or some side walls of said element have an oblique inclination between the bearing face and the rear face, allowing to arrange between the walls adjacent two elements contiguous a free space. These nine elements are placed against the front panel 4 in a contiguous manner, in three columns and three rows, the bearing faces 2 being adjacent to each other.

  Once these nine reservation elements have been put in place against the front panel, the operator has positioned a welded mesh, of rectangular mesh, whose inner dimension of the mesh is slightly greater than the cross section of each element of reservation at the vertical plane in which the mesh must be 3 o positioned, usually the median plane of the formwork. Thus the lattice 18 is somehow fitted into the assembly formed by the nine elements 2857044 11 reservation, as shown in Figure 7. The back panel 9 is then put in place, with clamping of the formwork, then the concrete is sunk between the two banks 4, 9.

  The concrete is spread around the nine reservation elements, and also in the spaces 19 created due to the inclination of the side walls 5a. During stripping, there may remain concrete remains attached to the lattice 18 in said spaces 19. However their recess is easily achieved by the operator with a simple hammer blow.

  Thus, a reservation area of average size, corresponding to nine reservation elements, is obtained in which zone a welded mesh 18 is held vertically.

  In the example above, the reinforcement constituted by a welded mesh is placed in the formwork, in a vertical plane. This is not exclusive of the invention, the armature can take any shape and also be placed in a horizontal plane or in any other way in the free spaces between the different elements of reservation. This reinforcement, available in the reservation area, delimited by all the reservation elements, possibly after removal of the concrete remains as indicated above, can be used in particular for anchoring other parts of the structure.

2857044 12

Claims (12)

  1. Formwork element for forming a small-sized reservation across the entire width of a concrete structure, comprising a plastics reservation box having a bearing surface equipped with magnetic means for fixing it on a metal section of the formwork, characterized in that it comprises a striking piece (6), opposite the bearing face (2) of the reservation box (5) whose mechanical resistance to impact under the action of a hammer and / or the removable character, can withstand at least 1 or 40 stripping operations.   2. Element according to claim 1 characterized in that the striking piece (6) is constituted by the face of the reservation box which is opposite to the bearing face, and which has a resistance to the impact of less than 500 joules.   3. Element according to claim 2 characterized in that it consists of a hollow plastic box, low density, whose striking face has a greater thickness than the other faces, preferably obtained by rotational molding.   4. Element according to claim 1 characterized in that the striking piece is an interchangeable piece (6), which is attached to the rear face (7) of the reservation box (5) of plastic material, including a piece of wood , or a piece of high density plastic material.   5. Element according to claim 4 characterized in that the interchangeable part (6) is attached by screwing on the rear face (7) of the reservation box (5) having threaded inserts (8).   6. Element according to one of claims 4 or 5 characterized in that it comprises a compressible material (11), which is disposed between the reservation box (5) and the striking plate (6).   3o 7. Element according to one of claims 1 to 6 characterized in that the bearing face (7) comprises housings for the magnetic means 2857044 13, and a compressible material is disposed between the magnetized means and the bottom of said housing.   8. Element according to one of claims 1 to 3 characterized in that its blocking by compression is obtained thanks to the capacity of elastic deformation of the side wall or walls of the reservation box (5) under the effect of pressure .   9. Element according to claim 8 characterized in that the side wall (5a) (or some of the side faces) of the reservation box (5) has an oblique, convergent inclination, from the bearing face (2) to the rear face (7), said inclination having a convex curvature.   10. Formwork assembly comprising a plurality of reservation elements (1) according to one of claims 1 to 9 and at least one armature characterized in that, the or the side walls (5a) of the reservation box (5). ) having a convergent oblique inclination of angle a, from the bearing face (2) to the rear face (7), the bearing faces (2) of the different reservation elements (1) are arranged adjacent to each other on the front wall (4) so that between all adjacent side walls (5a) there is at least one free space (19) for placement of a frame (18) within the formwork, at least in the reservation area delimited by the booking elements.   11. The assembly of claim 10 characterized in that the frame is a welded mesh (18) whose inner dimension of the mesh is slightly greater than the cross section of each reservation element (1) at the vertical plane according to which the mesh must be positioned in the formwork.   12. The assembly of claim 11 characterized in that the inclination angle a is such that tga is at least slightly greater than d / L, d being the diameter of each wire welded mesh (18) and L the width of the formwork.