EP0950780B1 - Device for positioning rebars in a shuttering for the execution of a construction in reinforced concrete - Google Patents

Abstract

The device comprises a support (3) to fix the rods (10) in the required position, projecting from one of the support's faces. The support and rods are held together by a sleeve (25) of stretch plastic wrapped round the support and having a tear-off strip (20) along one face, passing between the U-shaped projections of the reinforcing rods. POLYMER -

Description

The invention relates to a positioning device for reinforcing rods in a formwork for the realization of a reinforced concrete structure, according to the preamble of claim 1.

Such a device is known from document DE-A-3 223 200.

When making a reinforced concrete structure, it is known to have reinforcing rods, generally metallic, a first part of which is trapped in a first mass of concrete as they protrude outside of this mass of concrete, so that another part can be immobilized in a second mass of concrete, especially during the construction of a second adjoining structure. This provision is used in particular for the realization of buildings anti-seismic standards.

Protect the ends of the reinforcing rods protruding outside the first mass of concrete in order to reduce the risk of accident or deterioration of these rods, by oxidation due to bad weather, and for aesthetic reasons. To do this, it is known, for example from DE-A-32 23 200, to have bent reinforcing rods in U shape extending from one side of a board forming a support, so as to penetrate into a mass of concrete in setting course, the board of which forms part of the formwork. To immobilize the reinforcements in relation to the board, DE-A-32 23 200, as well as FR-A-2 732 994, teach to use a heat-shrinkable sheath which surrounds both the board and part of the reinforcements. The use of heat shrink tubing is relatively complex since it is necessary to heat the sheath during the manufacturing of the devices, which induces a cost of relatively high manufacturing. In addition, a heat-shrinkable sheath is not very resistant to the point that you cannot exclude displacements of the reinforcing rods relative to the board, these displacements can result in a bad positioning of the reinforcing rods with respect to the mass of concrete. It is necessary to check, during the installation of the board at the time of formwork of the concrete mass, the position of each frame relative to this board. This requires skilled labor and extends the time pose. Finally, heat shrink tubing is generally made from polyethylene which is not treated against ultraviolet, so they tend to fall apart after a relatively long exposure outside, this which can occur during storage, but also when the board remains on hold for several years on a building already constructed.

Finally, when it is necessary to use the reinforcements for connection to a second mass of concrete, it remove the board and the remainders from the sheath heat-shrinkable to allow an intimate attachment between the two concrete masses. Documents DE-A-4 005 852 and EP-A-0 119 940 show devices for positioning reinforcing rods, the support of which is provided with tear strips facilitating its extraction. In devices without a tear strip, a operator must pull on all the pieces of sheath that have tendency to fall apart or get stuck in the gaps of the concrete mass already formed, so that there remains usually a few pieces of sheath between the two masses of concrete. This operation of collecting pieces of sheath is tedious and sometimes it is not done with the greatest care. This results in an ineffective join between the two concrete masses.

It is to these disadvantages that we hear more particularly remedy the invention.

In this spirit, the invention relates to a device for positioning of reinforcing rods in a formwork for the realization of a reinforced concrete structure, this device comprising a support capable of immobilizing the rods in a position such that a part of these rods extends towards the outside of the device from one side of the support, this support and these rods being surrounded by a position holding sheath relative, characterized in that the sheath is formed by winding of stretch film around the support and in that minus a tear strip extends on an outer face of the film, on the side of the support face from which extend the rods outward.

The use of a rolled up stretch film for manufacturing the sheath solves the problems mentioned above by reference to a heat-shrinkable sheath because a stretch film is denser than a thermoformed sheath while it is more quicker and easier to set up. In particular, a stretch film can be wrapped around the support on several thicknesses, which gives it excellent properties of maintenance. Indeed, when a reinforcing rod is introduced under the holding sheath formed by the stretch film by crossing, this one is torn on a small part, but remains effective over most of its length because it is made up of several thicknesses. This is an advantage substantial compared to thermoformed sheaths which, when are pierced for the introduction of the rods of frames, tend to tear at the holes thus realized.

Furthermore, thanks to the tear-off strip arranged between the sheath and the concrete mass, it is possible, after having removed the backing, to exercise on the tape tearing off a tensile force inducing detachment of the complete sheath relative to the mass of concrete. This therefore allows, by a simple operation, to recover all a support sheath, which greatly facilitates the work of a mason.

According to a first advantageous aspect of the invention, the tear strip is arranged so that it does not do not cover the parts of the reinforcing rods arranged at the surface or in the support. This aspect of the invention guarantees no interference occurs between the tear strip and the reinforcing rods which therefore do not hinder the extraction of the tear strip and sheath. In this case, we can provide that the rods have an overall U shape while the tear strip is disposed between the branches of these rods, in a direction generally parallel to these branches.

According to another advantageous aspect of the invention, the strip tear is placed around the support, overflowing on a face of the support opposite to the face from which extend the rods. This aspect of the invention allows a mason catching both ends of the tear strip which protrude outside the mass of concrete already formed to exert a tensile force on the tear strip. In this case, provision can be made for the tear strip to be reinforced, at least in an overlap area on one side of the support.

According to another advantageous aspect of the invention, the strip door, on its face in contact with the sheath, a adhesive coating. This aspect of the invention guarantees a effective positioning of the tear tape relative to to the sheath during storage and installation of the device.

It is further possible to provide that the stretch film bears, on its side facing the support, an adhesive coating, which contributes to better immobilization compared to this support and, consequently, better maintenance of reinforcing rods. The stretch film can be made in polyethylene or polyvinyl chloride treated anti UV, this which gives it excellent stability over time.

• la figure 1 est une représentation schématique en perspective d'un dispositif conforme à l'invention, lors d'une première étape de fabrication ;
• la figure 2 est une représentation schématique de principe d'une seconde étape de fabrication du dispositif de la figure 1 ;
• la figure 3 est une représentation schématique de principe d'un dispositif conforme à l'invention au terme de sa fabrication ;
• la figure 4 est une vue en perspective de principe du dispositif de la figure 3 lors d'une première étape d'utilisation et
• les figures 5 à 7 sont des vues analogues à la figure 4 pour des étapes d'utilisation ultérieures.

The invention will be better understood and other advantages thereof will appear more clearly in the light of the following description of an embodiment of a device for positioning reinforcing rods in accordance with its principle, its manufacturing process and its method of use, given solely by way of example and with reference to the appended drawings in which:

• Figure 1 is a schematic perspective representation of a device according to the invention, during a first manufacturing step;
• Figure 2 is a schematic representation of the principle of a second manufacturing step of the device of Figure 1;
• Figure 3 is a schematic representation of the principle of a device according to the invention at the end of its manufacture;
• FIG. 4 is a perspective view in principle of the device of FIG. 3 during a first step of use and
• Figures 5 to 7 are views similar to Figure 4 for subsequent stages of use.

In FIG. 1, a winder 1 is used to arrange a stretch film 2 around a board 3 provided with two grooves 4 and 5. This winder is a classic material including the operation is very well controlled, so that it can work at a very high rate with satisfactory quality. The advance of the board 3 in the winder 1 is adjusted by so that the stretch film 2 is wound on several thicknesses around the board 3.

As can be seen more clearly from FIG. 2, a rod of folded U-shaped metal frame 10 includes two branches 11 and 12 parallel to each other and overall perpendicular to a U-shaped part 13. The formwork 11 and 12 are scheduled to be received respectively within grooves 4 and 5 of plate 3.

Before the establishment of the rod 10 on the board 3, a strip 20 of reinforced adhesive tape is stuck on the film stretchable 2, along the length of the board 3, between the grooves 4 and 5.

It is noted that the band 20 extends protruding from the face 3 a of the board 3 in which are provided the grooves 4 and 5 around a side 3b of the plate 3 perpendicular to the face 3a, so that its end 20 may be folded in the direction of the arrow F in Figure 2 of a portion of the film 2 disposed on one side 3c of the board 3 opposite to the face 3 a. The arrangement of the strip 20 is similar to the other end of the board 3 which is not shown.

Given the small radius of curvature imposed on the strip 20 at the edges between the side 3 b and the faces 3 a and 3 c of the board 3, it can be provided that the strip 20 is reinforced, in its area 20 b of covering on the 3 b side, with fibers, for example organic fibers. It can also be provided that the strip 20 is homogeneous, that is to say comprises reinforcing fibers over its entire length.

The rod 10 is placed on the board 3 by making in the film 2 two orifices 14 and 15 arranged respectively above grooves 4 and 5. When the free ends of branches 11 and 12 have entered gorges 4 and 5, it is possible to make the rebar 10 move of rotation, represented by the arrow R in FIG. 2, of so as to penetrate all of the branches 11 and 12 into the grooves 4 and 5 through the orifices 14 and 15.

Several reinforcements 10 may be disposed on the board's length 3 so as to obtain the configuration that is shown in Figure 3, wherein the portions 13 of the rods 10 extend generally perpendicular to the face 3 a of the board 3 The stretch film placed around the board 3 and the branches 11 and 12 of the rods 10 thus constitutes a sheath 25 for holding these rods relative to the board 3.

In the arrangement of Figure 3, we note that the strip 20 is arranged between the branches 11 and 12 of the reinforcing rods 10 by being parallel to these branches, that is to say parallel to the largest axis XX 'of plate 3.

The use of the device of the invention is explained with reference to FIGS. 4 to 7. The device can be incorporated into a concrete mass 30 in which the parts 13 of the reinforcing rods 10 which it comprises are trapped. When the concrete mass 30 has been décoffrée, the face 3c of the board 3 is exposed, through the sheath 25 which is advantageously transparent. The ends 20a of the strip 20, which are readily identifiable because they have a different texture of the film 2, are visible on this side 3 c. When it is necessary to remove the board 3 to use the free ends of the rods 10 formed by the panels 11 and 12, the sheath 25 is sliced over the entire height of the board 3, so that the film 2 can be spread on either side of the plate 3. the ends 20 a of the strip 20 have been previously discarded, as shown in Figure 5.

It is then possible to exert on the two ends 20 a of the strip 20 a tensile force represented by the arrow T to take off the board 3 from the housing 30 a which it has created in the mass of concrete 30. A mason can then easily extract the board 3 from the housing 30 a . However, according to a conventional approach, a mason can also extract the board 3 from the housing 30 a by inserting between the latter and one of the faces of the housing 30 has a lever formed, for example, by the tip of a tool.

We are then in the position of FIG. 6 in which the film 2 remains pressed against the walls of the housing 30 a while it is possible to straighten the branches 11 and 12 of the rods 10 in the direction represented by the arrow F 'at Figure 6.

When the branches 11 and 12 have been straightened so as to be generally perpendicular to the bottom of the housing 30 a , the ends 20 a of the strip 20 can be pulled, as shown by the tensile force T 'at la. Figure 6, so that the entire film 2 is detached from the bottom and sides of the housing 30 a , which allows it to be removed in a particularly simple operation, as shown in Figure 7. The tear tape 20 , which is arranged behind the remainder of the sheath 25 formed by the plastic film 2 in the position of FIG. 7, makes it possible to exert on this remainder a tearing or tensile force T 'distributed homogeneously over the entire height of this movie.

The arrangement of the strip 20 between the branches 11 and 12 rods 10 avoids any interference between this strip and these branches when passing from the position of the Figure 6 to that of Figure 7.

The band 20 can be used whatever the material constituting the sheath 25 and, in particular, with a sheath heat-shrinkable. However, the use of stretch film 2 is particularly advantageous and it can be expected that this stretch film has an adhesive coating on its intended side to form the inner surface of the sheath 25, that is to say on its side facing the plate 3 and the branches 11 and 12 of the rods 10, which further improves the retention of the rods in position. Film 2 can be made of polyethylene with a anti-UV treatment, or polyvinyl chloride (PVC) with the same type of treatment which includes the addition of an additive specific to the masterbatch of the plastic to be formed.

The invention has been represented with a support formed by a wooden board, of course any other material can be used for support, in particular a metal, a plastic material or a composite resin. Likewise, rods can be made made of metal, for example steel, or any other material approved to constitute the reinforcement of a concrete mass.

Depending on the width of the support used for the reinforcing rods, several tear strips can, the if necessary, be placed on the retaining sheath. In this case, we can predict that they are parallel to each other compared to others or, on the contrary, secant.

Claims (9)

1. A positioning device of reinforcing rods in a formwork for creating a structure in reinforced concrete, the said device comprising a support member (3) capable of securing the said reinforcing rods in a position such that part of the said reinforcing rods extends towards the exterior of the said device from one surface (3a) of the said support member, the said support member and the said reinforcing rods being encased in a support sheath (25) in a relative position, characterised in that the said sheath (25) is formed from stretchable film (2) wrapped around the said support member (3) and in that at least one removal band (20) is laid over an external surface of the said film (2), towards the said surface (3a) of the said support member (3).
2. Positioning device according to claim 1, characterised in that the said removal band (20) is placed such that it does not cover the parts (11, 12) of the said reinforcing rods (10) placed on the surface (3a) of or in (4, 5) the said support member (3).
3. Positioning device according to claim 2, characterised in that the said reinforcing rods (10) have an overall U shape and in that the said removal band (20) is placed between the arms (11, 12) of the said rods in a direction (XX) parallel overall with the said arms.
4. Positioning device according to one of the preceding claims, characterised in that the said removal band (20) is placed around the said support member (3), protruding from one surface (3c) of the said support member opposite the said surface (3a) from which the said parts (13) of the said rods extend.
5. Positioning device according to claim 4, characterised in that the said removal band (20) is reinforced, at least in one part (20b) where it covers one surface (3c) of the said support member (3).
6. Positioning device according to one of the preceding claims , characterised in that the said removal band (20) has, on the surface in contact with the said sheath (25), an adhesive coating.
7. Positioning device according to one of the preceding claims, characterised in that the said stretchable film (2) has, on the surface facing the said support member (3), an adhesive coating.
8. Positioning device according to one of the preceding claims, characterised in that the said stretchable film (2) is wound in several layers around the said support member (3).
9. Positioning device according to one of the preceding claims, characterised in that the said stretchable film (2) is made of polyethylene or anti-UV treated polyvinyl chloride.

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