FR2776320A1 - Coffer for building connection frames - Google Patents

Abstract

The coffer comprises, on its plastics bottom (2) which is in contact with the concrete, a succession of aligned drillings for the passage of the curved ends (9a) of connection frames (9). A metal wire (110) runs along the internal or external face of the bottom with its ends passing through the drillings. This enables a cutting out by the wire of the bottom along the drillings during extraction of the coffer.

Description

WAITING BOX FOR LINK REINFORCEMENTS
The present invention relates to a waiting box for connecting fittings
We already know waiting boxes consisting of a metal sheet box having an elongated shape, of substantially trapezoidal tranavesale section, and having an opening on the face corresponding to the large base, and of a plastic cover to seal this opening. When the longitudinal ends of the box are openings, plugs are provided to close said open ends and thus prevent the concrete from running into the box.
To install such a waiting box, we just insert the free curved ends of the connecting frames in the box, through holes in the metal bottom of the box. Then, the cover is mounted on the box and the box is pressed by its cover against a metal formwork to prevent concrete from flowing between the formwork and the box. Once the box is correctly positioned, it is fixed in position on the formwork. Finally, the concrete is poured between the metal forms to make a concrete structure, in which a reservation is provided by the waiting box for the connection reinforcements.
This type of waiting box, however, has the disadvantages of an imprecise positioning of the box relative to the formwork and the need to provide additional fixing means between the box and the formwork. In addition, when the plastic cover is removed from the box to access the waiting reinforcements, the rest of the box, namely the metal box, remains in place in the concrete structure, which can cause cracks to appear in concrete by corrosion of the canister. On the other hand, it cannot be guaranteed that such a box is correctly pressed against the formwork, so that concrete can flow in Interface between the box cover and the formwork, which can complicate the removal of the cover and / or deteriorate it
The first object of the invention is therefore to eliminate the aforementioned drawbacks and to propose a waiting box for connection frames which can be correctly positioned and easily fixed on the metal formwork, while retaining the interface between the box cover. and the metal formwork as watertight as possible.

 For this purpose, the invention firstly has a waiting box for connecting frames, the box having an elongated cover intended to close an opening on the front face of a box which is intended to be pressed against a metal formwork before the pouring concrete to make a concrete structure, characterized in that the cover is made of magnetically soft material, while the box is made of plastic or the like, a housing being defined on the outer front face of the cover in order to accommodate and retain by magnetic attraction at least one magnetized piece which is flush with the external surface of the front face of the box, to retain and press the box against the metal formwork.

Advantageously, the magnetized part is in the form of a strip, a sheet or a stud.

 According to another characteristic, the longitudinal edges of the cover are curved inwards, for example substantially U-shaped, to define longitudinal grooves in which complementary ribs are engaged formed on an externally projecting rim of the box, at the level of reopening of the box In this case, the aforementioned housing is dii by a longitudinal recess on the external front face of the cover.

 In another variant, the longitudinal edges of the box have an internal longitudinal bead in which is provided a mortise for sliding therein in the longitudinal direction the respective longitudinal edges of the cover In this case, the aforementioned housing is defined between the front face of the cover and the plane passing through the front surface of the longitudinal edges of the box.

 To avoid leaving a part of the box in place in the concrete structure, several solutions were known which consisted in opening the bottom of the box along the line passing through the holes intended for the passage of the reinforcements, which made it possible to remove the box completely, because the curved ends of the frames no longer hold the bottom of the box. French Patent No. 2,602,534 provides a weakening line extending along the line of the holes intended for the reinforcements, for example a reduction in thickness or a succession of pre-openings, which makes it possible to extract completely the box by exerting traction on the accessible part of the box, in order to cause the bottom of the box to break along this line of weakness.

 However, this solution has the drawback of weakening the bottom of the box as well as a modification of the structure of the box, which increases the production cost.

 The second object of the invention is therefore to propose a waiting box for connection reinforcement, which can be completely removed from the concrete structure, without however weakening its structural integrity.

To this end, the second object of the invention is a waiting box for connecting reinforcement, comprising on its plastic or similar base, intended to be in contact with concrete, at least one succession of aligned holes for the passage of curved ends of the connection frames, characterized in that it comprises at least one metal wire which runs along the internal or external face of the bottom of the box and passes through its respective ends the two end bores of said succession of bores , to allow cutting by the wire of the bottom of the box along the holes, during the extraction of the box
In a particular embodiment, when the wire is placed on the internal face of the bottom of the box, the respective ends of the wire are intended to be wound on the external part of the connecting frame passing through the associated bore, so that the box can be cut by the wire, the ends of which are retained on the frame and embedded in the concrete, by simple pulling on the accessible part of the box. In this case, longitudinal reinforcing ribs can be provided on the internal face of the bottom of the box. on either side of the succession of holes, to guide the cutting by the wire
In another embodiment, when the wire is placed on the external face of the box bottom, at least one of the ends of the wire is free in the box to allow cutting of the bottom of the box by pulling on said free end of the wire. preferably, the other end of the wire is fixed to an internal part of a connecting frame or to a part of the box.

Advantageously, a protective lip is provided on the outer face of the bottom of the box, in the vicinity of the succession of holes, to cover the wire and at least partially isolate it from the concrete.
It should be noted that the characteristics of the box according to the first object of the invention can be taken individually or in combination with those of the box according to the second object of rinventi
The invention will be better understood, and other objects, details, characteristics and advantages thereof will appear more clearly during the explanatory description which will follow of several particular presently preferred embodiments of the invention, given solely by way of illustration. and not limiting, with reference to the appended schematic drawings, in which:
- Figure 1 is a cross-sectional view of a box according to the first object of the invention;
- Figure 2 is a half view in cross section showing a variant of the box according to the first litnrention object;
- Figure 3 is a schematic cross-sectional view showing two waiting boxes for a connecting frame in a concrete structure, according to the second object of the invention;
- Figure 4 is a sectional view along line IV of Figure 3;
- Figure 5 is a partial view, enlarged and in section along line V of lafigure4;
- Figure 6 is a schematic view similar to Figure 4, but on a smaller scale, illustrating the cutting of the box;
- Figure 7 is a view similar to Figure 3, but showing a variant of the box according to the second object of the invention;
- Figure 8 is a longitudinal sectional view along line VIII of Figure 7;
FIG. 9 is an enlarged partial view, and in section along the line DC of the figure; and
- Figure 10 is a schematic view, on a smaller scale, similar: in Figure 8, but showing the cutting of the calisson
According to the particular embodiment illustrated in FIG. 1, the waiting box according to the invention comprises a plastic or similar box 1 of elongated shape and of substantially trapezoidal cross section, said box being open on its face corresponding to the large base of the trapezoid, while it has on its bottom 2 corresponding to the small base of the trapezoid, a plurality of aligned bores 2a for the passage of the connecting armaters 9, the curved ends of which 9a are intended to be received inside of the box (see Figure 4). On the outer face of the bottom 2 of the box 1, small ridges 2b are provided to facilitate demolding of the concrete cover box
The box 1 has longitudinal edges 1a which project outwards relative to the central cover of the box. The edges 1a comprise a protruding rib forming a small bead on which a complementary curved edge 3a of a metallic cover made of magnetic material 3 is engaged. The cover 3 consists of an elongated sheet of sheet metal whose longitudinal edges 3a are folded inward substantially at C, for example by stamping or profiling.

 On its external front face, the cover 3 comprises a longitudinal recess 4 which is intended to receive one or more magnetized clamps 5, appearing for example in the form of a strip, a sheet or studs. Each part 5 is held in the recess 4 of the cover 3 by simple magnetic attraction. As visible in FIG. 1, the external front face of the magnetized part 5 is flush with the external front surface of the box.

 The cover 3 with the magnetized parts 5 is intended to be pressed against a metal formwork before the concrete is poured. The parts 5 will maintain the box against the metal formwork, while allowing precise positioning.

Fn addition, the cover 3 being pressed by magnetic attraction against the metal formwork, the interface between them is sealed against the pouring of the concrete, which keeps the cover 3 clean and facilitates its removal after the setting of the concrete.
In Figure 2, an alternative embodiment of this box is shown. The box 11 of this box has on its bottom 12 holes 12a similar to the aforementioned holes 2a. The longitudinal edges 11a of the box 11 are folded here towards the interior of the box and define, with an internal longitudinal bead 16, a groove or a mortise 17 substantially in the shape of an L opening into the plane of the opening of the box. This mortise 17 is intended to receive the longitudinal edge 13a of the cover 13, which edge 13a has a shape complementary to the mortise 17, to allow the cover 13 to be mounted on the box 11, by simple longitudinal sliding of the cover 13 by one longitudinal ends of mortises 17.

 Of similar mother, a magnetic strip 15 is placed against the external front face of the cover 13, but here the cover 13 does not have any recess because a housing 14 is defined between the external front face of the cover 13 and the external front surface of the rim folded lia from box 11.

 In the variants of FIGS. 1 and 2, the magnetized pieces are adapted to be flush with the external front surface of the box. The housing 14 for the magnets 15 is defined by the thickness of the folded rim 11a of the box 11.

 We will now briefly describe the use of the box of Figure 1, it being understood that the use of the box of Figure 2 is similar.

Connecting frames (not shown in Figures 1 and 2) are first inserted, by their curved ends, to sort the bottom 2 of the box 1, the cover 3 of which has been removed, passing through the holes 2a Then , the curved ends of the frames are tilted along the box 1 to allow the box to be closed with the cover 3 which engages on the edges 1a of the box 1, at the opening of the box. Finally, shutter plugs (not shown in Figures 1 and 2) are fitted on the longitudinal ends of the box, to seal the box against pouring concrete
Then, the box is pressed against a metal formwork and kept in the correct position thanks to the magnetic parts 5 which magnetically attract the cover 3 against the metal coking.

 After the concrete has been poured between the metal forms and the intake of the concrete structure, the metal forms are removed, which gives access to the visible part of the waiting box. We then exert a traction on the whole box, by lever effect, in order to extract the box from the concrete structure.

The cover 3 can also be removed first, which has been facilitated by the fact that the interface between the cover 3 and the metal coking has been made impervious to the pouring of the concrete. The rest of the box can then be torn off. exerting traction on the accessible part of the box, the folded ends of the frames helping to tear the bottom of the box.

Referring now to Figures 3 to 6, we will describe a means for cutting the bottom 2 of the box 1, for the extraction of the box. It should be noted that this box can be identical to that shown in FIG. 1 or 2, but can also be different.
As shown in Figure 4, the box is closed at its longitudinal ends by two plugs 8 having a rectangular trapezoidal shape, in longitudinal section, with its inclined side directed towards the concrete structure B, to facilitate the extraction of the box Of course, the plugs 8 have a profile complementary to that of the box 1.

 As can be seen in FIG. 5, the connection plates 9 pass through holes 2a in the bottom 2 of the box 1, with their curved ends 9a (see FIG. 4) which extend in the longitudinal direction inside the box Les curved ends 9a of annatwres 9 adopt this position, after tilting of the annature. In Figure 3, the frame 9 has a substantially U-shaped whose free ends are curved at 9a. The part of the frame 9 which is located outside the boxes is intended to be embedded in the concrete B.

 A stainless steel wire 10 is placed along the internal face of the bottom 2 of the box 1, so as to extend along the holes 2a of the bottom 2 of the box. The upper end strand 10a of the wire 10 passes through the upper hole in the bottom 2 of the box and is wound around the external part of the frame 9. The lower end strand 10b of the wire 10 passes through the lower hole in the bottom 2 of the box and is wound on the outer part of another frame 9. In this way, the wire 10 is fixed to the frames 9, at each end. In addition, as the end strands 10a and 10b of the wire 10 are embedded in the concrete with airnature 9, the wire 10 is firmly anchored at each end on the concrete structure B and therefore remains in place.

 As can be seen in FIG. 5, the wire 10 can be placed on one of the sides of the holes 2a, by rat with the reinforcements 9. Two longitudinal ribs 20 can project perpendicularly from the internal face of the bottom 2 of the box, and other of the series of holes 2a, to guide the wire 10 along the bottom of the box 1.

The cutting of the bottom 2 of the box 1 by the wire 10 is carried out as schematically illustrated in FIG. 6. By exerting a pull on the box, the cable 10 comes to cut the bottom 2 of the box, along a line passing approximately by the series of holes 2a, so that the entire box can be simply and quickly removed from its reservation in the concrete structure B, by a simple pull
Of course the wire 10 remains in place on the concrete cover B, but this cutting device does not weaken the bottom of the box, but on the contrary contributes to reinforce it, especially if reinforcing ribs 20 are provided. In addition, the establishment of the wire 10 is extremely simple and its cost is very low.

 In an alternative embodiment shown in FIGS. 7 to 10, the wire 110 is placed here along the external face of the bottom 2 of the box 1 and its upper end 110a and lower 110b strands pass through the longitudinal end holes from the bottom 2 of the box. As best seen in FIG. 8, the upper end strand 110a is free and has a terminal loop to facilitate its gripping, while the lower end strand 110b is wedged between the cover 3 and the lower obturator plug 8. However, one could alternatively provide the reverse, or else provide the two free end strands with a gripping loop, or alternatively provide that one of the end strands is attached to an internal part of a frame. 9.

 In FIG. 9, a protective lip 120 is formed on the external face of the bottom 2 of the box, in the vicinity or in alignment with the drilling series 2a, to at least partially cover the wire 110, and isolate it thus concrete B. Indeed, unlike wire 10, wire 110 is here intended to be removed with the box.

 Before pouring concrete B, the upper end strand 1 loua is left free inside the box. To extract the box, the cover 3 is first removed, and a tensile force is exerted on the loop of the strand 110a. , as indicated by the arrow Fl, which causes the bottom 2 of the box 1 to be cut along the holes 2a Once the box 1 is cut, it can be completely extracted from its reservation by exerting traction on the accessible part of the box, as indicated by the arrow F2.

 Of course, several metal wires could be provided, if necessary, in particular when several drilling lines are provided through the bottom of the box.

 Although the invention has been described in connection with particular embodiments, it is obvious that it is in no way limited thereto and that it includes all the technical equivalents of the means described as well as their combinations if these fall within the scope of the invention

Claims (12)

 1. Waiting box comprising on its bottom (2) made of plastic or the like, intended to be in contact with concrete (B1 at least one succession of aligned bores (2a) for the passage of the curved ends (9a) of the reinforcements link (9), characterized in that it comprises at least one metal wire (leu, 110) which runs along the internal or external face of the bottom of the box and passes through its respective ends (10a, lOb, 110a, llûb ) the two end bores of said succession of holes (2a), to allow cutting by the wire of the bottom of the box along the holes, during re-extraction of the box.  2. Waiting box according to claim 1, comprising an elongated cover (3, 13) intended to close an opening on the front face of a box (1, 11) which is intended to be pressed against a metal formwork before the pouring concrete to make a concrete structure (B), characterized in that the cover (3, 13) is made of maglletically soft material, while the box (1, 11) is made of plastic or the like, a housing (4 , 14) being defined on the external front face of the cover in order to be able to accommodate and retain therein by magnetic attraction at least one magnetized part (5, 15) which is flush with the external surface of the front face of the box, in order to retain and press the box against the metal formwork.  3. Waiting box according to claim 1 or 2, characterized in that, when the wire (10) is placed on the internal face of the bottom (2) of the box, the respective ends (10a, 10b) of the wire are intended to be wound on the external part of the connecting reinforcement (9) passing through the associated bore (2a), so that the box can be cut by the wire, the ends of which are retained on the reinforcement and embedded in the concrete, by simple pull on the accessible part of the box  4. Waiting box according to claim 3, characterized in that longitudinal reinforcing ribs (20) are provided on the internal face of the bottom of the box, on either side of the succession of bores (2a), for guide the cut by the wire (10).  5. Waiting box according to claim 1 or 2, characterized in that, when the wire (110) is placed on the external face of the bottom (2) of the box, at least one of the ends of the wire (110a, 110b) is free in the box, to allow cutting of the bottom of the box by pulling on said free end (1 10a) of the fit  6. Waiting box according to claim 5, characterized in that the other end (110b) of the wire (110) is fixed to an internal part of a connecting frame or to a part of the box.  7. Waiting box according to claim 5, characterized in that a protective lip (120) is provided on the external face of the bottom (2) of the box, in the vicinity of the succession of bores (2a), to cover the wire (110) and at least partially isolate it from the concrete (B).  8. Waiting box according to claim 2, characterized in that the magnetized part is in the form of a strip (15), a sheet or dlufl pad (5).  9. Waiting box according to claim 2, characterized in that the longitudinal edges (3a) of the cover (3) are curved inwards, for example substantially U-shaped, to define longitudinal grooves in which come to engage complementary ribs formed on an externally projecting rim (la) of the box (1), at the level of cover of the box  10. Waiting box according to claim 9, characterized in that the aforementioned housing (4) is defined by a longitudinal recess on the external front face of the cover (3).  11. Waiting box according to claim 2, characterized in that the longitudinal edges (11a) of the box (11) comprise an internal longitudinal bead (16) in which is provided a mortise (17) for receiving therein sliding in the longitudinal direction the respective longitudinal edges (13a) of the cover (13).  12. Waiting box according to claim 11, characterized in that the aforesaid housing (14) is defined between the front face of the cover (13) and the plane passing through the front surface of the longitudinal edges (1 la) of the box (11).