EP0290544A1

EP0290544A1 - Tubular mould for a rectilinear component or cavity, of non-circular cross-section, particularly for moulding concrete

Info

Publication number: EP0290544A1
Application number: EP87907618A
Authority: EP
Inventors: Guy Jacob; Yvan Toni
Original assignee: Sofratube R C T (sa); Sofratube RCT SA
Current assignee: Sofratube R C T (sa); Sofratube RCT SA
Priority date: 1986-11-14
Filing date: 1987-11-13
Publication date: 1988-11-17
Also published as: IT8722586A0; JPH01501407A; IT1223094B; WO1988003590A1

Abstract

L'invention vise à permettre l'utilisation d'éléments tubulaires en carton pour former des moules ayant une section constante non circulaire. Les parois de l'élément tubulaire de moulage en carton (11) sont épaulées au moyen d'un calage en mousse synthétique ou en carton, par exemple des tubes cylindriques en carton (13, 14) disposés longitudinalement, pour empêcher une déformation des parois sous la poussée de la matière à mouler. Ces tubes sont soutenus par un tube extérieur en carton (12). Des moyens de soutien similaires sont prévus à l'intérieur d'un tube en carton de section polygonale pour mouler un évidement ou pour constituer un corps creux en carton. L'invention est utilisable pour coffrer du béton ou pour mouler toute autre matière durcissant dans la masse.The invention aims to enable the use of tubular cardboard elements to form molds having a constant non-circular section. The walls of the tubular cardboard molding element (11) are supported by means of synthetic foam or cardboard cushioning, for example cylindrical cardboard tubes (13, 14) arranged longitudinally, to prevent deformation of the walls under the pressure of the material to be molded. These tubes are supported by an outer cardboard tube (12). Similar support means are provided inside a cardboard tube of polygonal section to mold a recess or to constitute a hollow cardboard body. The invention can be used for forming concrete or for molding any other mass-hardening material.

Description

TUBULAR MOLD FOR A RECTILINEAR ELEMENT OR RECESS OF NON-CIRCULAR SECTION, IN PARTICULAR FOR FORMING CONCRETE

The present invention relates to a tubular mold for a rectilinear element or recess of constant non-circular section, in particular for formwork concrete, comprising at least one tubular molding element, the walls of which define said section, and support means for transversely supporting the tubular molding element.

To mold or form non-circular, and in particular prismatic, elements or recesses, a mold is generally used consisting of assembling different parts, each of which has a plane wall corresponding to a face or a fraction of a lateral face of the element to be mold. When molding relatively liquid materials, such as concrete, there are always sealing problems along the joints between these parts. To avoid leaks in these joints, the parts should be tightened tightly against each other, and also to prevent them from deforming under the pressure they undergo during molding. This requires very rigid members to support the walls of the mold.

To mold elements with a circular section, for example a cylindrical column or a cylindrical recess, these sealing problems are largely avoided by making the walls of the mold by means of a tubular element, which makes it possible to remove any longitudinal joint. . However, to remove this tubular element once the molded material has hardened, it is generally necessary to cut it and it is then no longer reusable as such. Items of this kind must therefore be inexpensive. For example, to form cylindrical concrete elements, it is known to use cylindrical cardboard tubes which are strong enough to support without deforming the transverse thrust of the fresh concrete.

For formwork, simply cut the cardboard tube following a generator, with a simple cutting tool. Cardboard cylindrical tubes are advantageous in that they are light while being rigid, therefore easy to set up, in that they are inexpensive, in particular because they can be manufactured continuously by helically winding strips of cardboard or paper, and in that they can be delivered in large lengths, which can easily be cut at the time of use.

However, we do not benefit from the same facilities for molding prismatic elements. The planar walls ^r a cardboard tube having this shape tend to deform excessively, unless they are given a very thick or that the shoulder by a sufficiently rigid structure, which is generally expensive and encombran¬ you .

Consequently, the object of the present invention is to provide a tubular mold of the type indicated in the preamble, having advantages similar to those of cylindrical cardboard molds, without comprising support means which are heavy and expensive.

For this purpose, the invention provides a tubular mold which is characterized in that the tubular molding element is made of cardboard, whether or not provided with a coating, and in that the support means comprise at least one cylindrical cardboard tube arranged along the tubular molding element to support it.

Preferably, the tubular molding element is a cardboard tube of polygonal section. According to a variant, this tubular element can be formed by a cardboard plate which is folded along parallel longitudinal lines and, the two opposite longitudinal edges of which are assembled. In another variant, the tubular element can be formed of several longitudinal strips cut from a cylindrical cardboard tube.

In the preferred embodiment, the support means comprise a cardboard support tube and several cylindrical wedging tubes arranged longitudinally between the support tube and the tubular molding element. In most cases, the support tube can be cylindrical. For the molding of a prismatic element of rectangular section, an advantageous embodiment of the mold comprises a rectangular inner tube, an outer support tube whose inner surface is in contact with the angles of the inner tube, and cylindrical wedging tubes. , all these tubes being made of cardboard.

For molding a recess, the support means may consist simply of cylindrical cardboard tubes filling the interior of the tubular molding element. The invention makes it possible in particular to produce a tubular hollow body comprising an outer cardboard tube, of rectangular section provided with a plug at each end, to constitute a formwork for a parallelepipedic recess in a concrete construction. Preferably, the four sides of the outer tube and the two plugs are pressed against at least one cylindrical cardboard tube placed inside.

In an advantageous embodiment, the tubular molding element is an inner element with flat faces, the support means comprise a cylindrical outer cardboard tube surrounding the inner element, and shims arranged between the outer tube and the flat faces of the inner element.

The wedges can advantageously be made of cellular or corrugated cardboard. Preferably, they are made of sheets of corrugated or corrugated cardboard which are folded along lines parallel to the axis of the mold. These folded plates may each comprise at least one part extending perpendicular to a face of the interior element, between this face and the exterior element.

According to a variant, the shims can be made of precut synthetic foam or injected into the mold.

In a preferred embodiment, the inner element is formed of at least one rigid plate of cellular or corrugated cardboard which is folded at the angles located between said planar faces. In addition to the setting made against the flat faces, the angles of the interior element can be support against the outer tube. In a particular form provided in particular for the formwork of a concrete pillar, the interior element defines a square or rectangular section whose angles are cut obliquely to form a chamfer.

To better understand the invention and its advantages, several embodiments will be described below, with reference to the appended drawings, in which:

FIG. 1 is a cross-sectional view of a first embodiment of a formwork for a concrete pillar of square section,

FIG. 2 is a view similar to FIG. 1, for a pillar of rectangular section,

FIG. 3 is a view similar to FIG. 1, for a pillar of hexagonal section,

The figure is a view similar to Figure 1, showing another embodiment of the formwork,

FIG. 5 represents a variant of the formwork of the figure,

FIG. 6 is a cross-sectional view of a formwork for a recess having a substantially square section,

FIG. 7 is a cross-sectional view of a formwork for a recess having a substantially rectangular section,

FIG. 8 is a perspective view of a hollow body having the section illustrated in FIG. 6,

FIG. 9 is an elevation view of an end-to-end connection of two tubular molding elements, FIG. 10 is a cross-sectional view of another embodiment of a tubular mold according to the invention, and

FIGS. 11 to 13 show in cross section three variants of a cardboard formwork for a square concrete pillar, each variant having a different type of shims,

FIG. 1 shows in cross section a formwork provided for a rectangular pillar and comprising yet another type of shims, and

Figure 15 shows a formwork similar to that of Figure 14, but provided with synthetic foam shims.

The tubular forms 10, 20 and 30 shown respectively in FIGS. 1, 2 and 3 comprise an inner cardboard molding tube 11,

21, 31 of polygonal section, housed inside a cylindrical support tube 12 which is also made of cardboard. The cross section of the tube H is square, that of the tube 21 is rectangular and that of the tube 31 is hexagonal, but these sections are all inscribed in the inner circumference of the support tube 12, so that the angles of the molding tubes are of preferably pressed against the support tube. Between these angles, the faces of the tubes 1 1, 21, 31 are essentially flat and they are supported externally by wedging tubes 13, 14 whose respective diameters are such that they are in contact with both the molding tube and the support tube, and between them in the case of FIGS. 1 and 2. The wedging tubes are also made of cardboard, and they have a relatively large thickness so as to be non-deformable and to transmit the thrusts to the external support tube 12 exerted by the fresh concrete on the flat walls of the inner molding tube. In the case of FIG. 2, the short sides of the tube 21 are relatively short and therefore rigid enough not to require wedging.

It should be noted that the cardboard wedging tubes 13, 14 can be replaced by rigid tubes made of another material, for example a synthetic material such as PVC, or by other wedging elements such as elements dishes, wooden slats, sand, synthetic foam, etc .... In all cases, the use of a cardboard tube to form the walls of the mold is advantageous from the point of view of sealing, cost and the ease of demolding. Of course, these walls can be provided with a waterproof coating as used in cylindrical formwork tubes. The tube can also be sealed using a paraffin application. For its part, the cylindrical tube 12 has the advantage of great rigidity in all directions, while being light and inexpensive. It should also be noted that after the concrete has set, the support tube 12 can be removed directly and the wedging tubes 13 and 14 retrieved for reuse, while the mounting tube can remain on the concrete for a longer period of time. protect it from drying out.

In the example of formwork 40, illustrated by FIG. 4, a square inner tube 41 made of cardboard is supported by a square outer tube 42 also made of cardboard, by means of wedging tubes 43 applied against the inner angles of the tube 42 and against the middle of the outer faces of the tube 41. In addition, the angles of the inner tube are pressed against the outer tube. Preferably, the angles of the outer tube 42 are rounded with the same radius as the wedging tubes 43. Thus, the section of the tube 42 does not deform absolutely when the tubes 43 are pushed outward.

The formwork 40 can be used to mold for example a square pillar in the inner tube 41. However, this formwork can also be used to form recesses or reservations thanks to the outer tube 42 by applying a waterproof coating if necessary. , so that the formwork 40 made entirely of cardboard proves to be versatile and economical.

The formwork 50 illustrated in FIG. 5 has the same configuration as the formwork 40, but the external support tube 42 is replaced by steel strips 52 which encircle the four wedging tubes 43 by pressing them lightly against the internal tube 41 It is obvious that it is very easy to assemble such a formwork on the site. Figures 6 and 7 show in section prismatic recess formwork, with outer cardboard tubes 61, 71 which serve as molding elements. The walls of these elements are supported by internal support tubes 62, 72 and wedging tubes 73. In the case of FIG. 6, wedging tubes 63 may possibly be provided in the corners of the square tube 61. Of course , we can imagine many other similar forms of molds, with flat or curved walls, and all kinds of different distributions of the support tubes and wedging tubes, in particular depending on the number of desired support points, along faces of the molding element.

FIG. 8 illustrates an advantageous use of the tubular element represented by FIG. 6, to constitute a hollow body 80 for the formwork of open or closed recesses in a concrete construction. To this end, the outer tube 61 of the tubular formwork is closed at each end by a cardboard plug 81 having an outer rim 82. It is noted that these plugs are supported not only on the ends of the tubes 61, but also on those of the tubes 62 and 63 it contains. The plugs are thus suitably shouldered and they maintain a tight closure of the two ends of the tube 61. Such a hollow body of square or rectangular section is inexpensive and it makes it possible to avoid the use of traditional cylindrical hollow bodies during the construction of thick slabs hollowed out. Indeed, the prismatic hollow bodies make it possible to save a greater volume of concrete, for a given spacing between the hollow bodies, and they facilitate the shaping and the laying of reinforcing steels.

In general, cardboard tubes of polygonal section, such as square tubes, are not produced continuously, but in fixed lengths between one and two meters. When using them for example for the formwork of concrete pillars, it is therefore necessary to connect tube elements end to end, which can be done in a simple way as shown in Figure 9. The ends of two square tubes 11 (FIG. 1) are butted together in the wet state and a strip of pre-glued wet paper is wound externally over several turns around the connector to form a sleeve 83. When removing the paper involved in drying, a tightening phenomenon occurs which ensures a rigid and tight junction of the tube elements 11.

FIG. 10 illustrates an embodiment of a mold which makes it possible to avoid the connections described above, by using only cylindrical cardboard tubes, which are produced economically continuously and are available in any length. In this example, to mold an element of square section, a tubular molding element is constituted by means of four segments 1 cut longitudinally from a cylindrical cardboard tube, of large diameter. The segments 1 are simply placed edge to edge inside a support tube 92 which is also a cylindrical cardboard tube. During molding, the pressure of the material flexes transversely of the segments 1, which tend to straighten and apply in a sealed manner against the edges of the adjacent segments. Of course, the thickness of the segments 91 and that of the tube 92 must be chosen appropriately so that the segments 91 are practically flat after deformation.

In the case of Figures 1 to 9, depending on the particular dimensions of the pillar to be shuttered, it may be difficult to find wedging tubes having the desired diameter, determined by the respective dimensions of the inner tube and the outer tube. To avoid this drawback, the formwork can be produced as shown in Figures I I to 15.

With reference to FIGS. 11 to 13, a tubular internal element 101 of cardboard constitutes the formwork wall of a concrete pillar with a square section with chamfered angles. Preferably, the inner surface of the element 101 is provided with a waterproof and non-stick coating with respect to the concrete, either by coating with glue of the "hot-melt" type, or by application of a layer of polyethylene or other. The element 101 is supported externally to avoid its deformation under the pressure of the fresh concrete, thanks to a cylindrical outer cardboard tube 102 and shims 103, 104 or 105 which are inserted between the outer tube 102 and each of the large flat faces of the inner element 101. To lighten the drawing, only one set of shims 103 to 105 has been shown in each of the figures.

9 -

The internal element 101 is preferably produced by means of a large sheet of cellular or corrugated cardboard in which seven longitudinal folds 106 have been made (FIG. 11) to give it the desired shape, the opposite edges of the plate being assembled. in a corner, for example by means of a simple self-adhesive strip 107. The four chamfers of the angles of the internal element 101 bear against the external tube 102, possibly by means of shims if the external tube does not have the optimal diameter.

In the case of FIG. 11, the shims 103 are formed from strips cut from double-layer corrugated cardboard plates, each strip being folded in the middle after cutting one of its faces. Once folded, each band forms a double wedge which can be placed substantially perpendicular to the flat face 108, as well as to the surface of the outer tube 102, as shown in the figure.

In the case of FIG. 12, two wedges 104 are provided against each wall 108, each of which is made of a corrugated cardboard plate folded approximately in the shape of an isosceles triangle. As shown in FIG. 12, this arrangement means that the central part 109 of each plate is held in a position approximately perpendicular to the walls of the tubes 101 and 102 by the two other parts of the wedge, which are supported in the vicinity of the corner of the internal element 101, and by the other wedge 104.

In the case of FIG. 13, the wedges 105 are superimposed sheets of cellular cardboard which are clamped along the walls 108 of the internal element 101. In this way, the walls 108 are supported over a large part of their width and they are kept perfectly flat thanks to the rigidity of the plates 105. It is possible to use plates 105 of different thicknesses in the same stack, so that the edges of these plates form several lines of support against the outer tube 102. In the example shown, there are four support lines for each face 108, in addition to the angles. Figure 14 shows an example of formwork for a rectangular pillar with chamfered angles. An inner tubular element 111 having this shape is made of cardboard in the same way as the element 101 described above. Its 45 ° chamfer angles can be wedged against the outer tube 102 using simple strips of cardboard

1 12 slightly bonded to the element 111. The small faces 113 of this element are wedged against the outer tube using shims 103 described with reference to FIG. 11. In the present case, each of the large faces 114 of the interior element 111 is held flat by support of a rigid panel 115, for example of wood agglomerate, this panel itself bearing against the outer tube 102 by means of cardboard wedges such as wedges 103 or by means of a other type of shims, for example linear or point wooden shims. With such a system, the panels 115 do not need to be cut to precise dimensions, nor to be drilled or adjusted to other structural elements, they are not altered by concrete, they can be removed easily removed from formwork and reused many times, even in forms with different dimensions. Consequently, the formwork illustrated here can have a rigidity equivalent to that of a traditional wooden formwork, but it is easier to make and dismantle, and it is much more economical.

Figure 15 shows an example of formwork having the same inner tubular element 1 1 1 and the same outer tube 102 as the formwork illustrated in Figure 14. In this case, the wedges are made of bodies 1 16 and 117 of synthetic foam injected between elements 111 and 102, for example a polystyrene, polyurethane or other foam. Instead of these bodies injected in place, one could use synthetic foam bodies which are precut and then put in place like the shims 103 to 105 of the previous examples. Of course, the element 111 can be replaced by the tubes 11, 21 or 31 described above.

With the Formwork described above, the wedges, which are the largest part of the preparation work, can generally be recovered. It suffices to split the outer tube in two by cutting it lengthwise along the lines AA in Figure 11. This can be done for example already the day after concreting the pillar, while it remains much longer free from drying out in the inner tubular element 101 or 111.

Of course, an inner tubular element made of a folded cardboard plate, like the elements 101 and 11 1, can also be wedged against the outer tube 102 by means of cylindrical cardboard tubes, as described with reference to Figures 1 to 4.

The present invention is not limited to the examples described above and it allows multiple combinations of shapes as well as different materials. In particular, the term "cardboard" covers many compact or composite materials whose base is of paper origin. In addition, the cardboard tubular elements can advantageously be combined with support elements made of other materials, such as wooden or metal frames, boards, or steel ties. Cardboard tubes adapt easily to such elements thanks to the cutting and drilling facilities they present. Furthermore, molds according to the invention can be used not only with concrete, but in general with all the solidifying materials in the mass, for example plaster, food products such as jellies or ice creams, etc.

Claims

claims

1. Tubular mold for an element or a rectilinear recess of non-circular constant section, in particular for concrete formwork, comprising at least one tubular molding element, the walls of which define said section, and support means for transversely supporting the element. tubular molding, characterized in that the tubular molding element (11, 61, 91, 101, 111) is made of cardboard, whether or not provided with a coating, and in that the support means comprise at least one tube cardboard cylindrical (12, 13, 14, 62, 63, 92, '102) disposed along the tubular molding element to support it.

2. Mold according to claim 1, characterized in that the tubular molding element is formed of several longitudinal strips (91) cut from a cylindrical cardboard tube.

3. Mold according to claim 1, characterized in that the tubular molding element is formed from several longitudinal strips (91) cut from a cylindrical cardboard tube.

4. Mold according to claim l, characterized in that the support means comprise a cardboard support tube (12, 42, 62) and several cylindrical wedging tubes (13, 14, 43, 63) arranged longitudinally between the tube support and the tubular molding element (II, 41, 61).

5. Mold according to claim 4, characterized in that the support tube (12, 62) is cylindrical.

6. Mold according to claim 4 or 5, for molding a prismatic element of rectangular section, characterized in that it comprises a rectangular inner tube (II, 21, 41), an outer support tube (12, 42 ) whose inner surface is in contact with the corners of the inner tube, and of the wedging tubes (13, 14, 43), all these tubes being made of cardboard. ^'

7. Mold according to claim 1, for the formwork of recesses in a concrete construction, characterized in that it comprises an outer cardboard tube (61) of rectangular section, provided with a plug (81) at each end. , to form a parallelepiped formwork.

8. Mold according to claim 7, characterized in that the four sides of the outer tube and the two plugs are pressed against at least one cylindrical cardboard tube (62, 63) disposed inside.

9. Mold according to claim 1, characterized in that the tubular molding element is an inner element (101, 111) to. flat faces, and in that the support means comprise a cylindrical outer cardboard tube (102) surrounding the inner element, and shims (103 to 105, 115 to 117) disposed between the outer tube and the flat faces (108 , 113, 114) of the interior element.

10. Mold according to claim 9, characterized in that the shims (103 to 105) are made of cellular cardboard or. corrugated.

1 1. Mold according to claim 10, characterized in that the shims (103,

104) are made of sheets of corrugated or corrugated cardboard which are folded in lines parallel to the axis of the mold.

12. A mold according to claim 1 1, characterized in that said folded plates each comprise at least one part (103, 109) extending perpendicularly to a face of the inner element, between this face and the outer element.

13. Mold according to claim 9, characterized in that the shims (116, 117) are made of synthetic foam precut or injected into the mold.

14. Mold according to any one of the preceding claims, characterized in that the inner element (101, 111) is formed of at least one rigid plate of cellular or corrugated cardboard which is folded (at 106) at the angles between said planar faces.

15. A mold according to claim 14, characterized in that the angles of the inner element (101, 111) bear against the outer tube.

16. A mold according to claim 14 or 15, characterized in that the inner element (101, 111) defines a square or rectangular section whose angles are cut obliquely to form a chamfer.