FR2695589A1 - Sealing joint moulding process for concrete pipes - includes step of placing seal and annular element on forming ring and bonding by depression - Google Patents

Abstract

Concrete pipes (1) have a female end (3) fitting a male end with an annular sealing joint integral with the female end. In order to integrate the annular sealing joint (4) with a moulded annular element (7) and protect the female end of the hollow pipe, the seal is previously placed and moulded on a forming ring. The method includes the step of, the sealing joint and the annular element being placed on a forming ring, to mould them inside the female end. In the non convex parts of the external transverse section of the forming ring, the sealing joint is bonded by depressing it against the forming ring. USE - Integrated sealing joint moulded into female end of a concrete pipe.Is equally applicable to fabrication of hollow elements by moulding using other materials other than concrete.

Description

Method of manufacturing by molding hollow elements such as concrete pipe elements with integrated seal, and device for implementing this method.

 The present invention relates to a method of manufacturing by molding hollow elements such as concrete pipe elements each comprising at least one female butt for their connection by fitting a male butt of an element in a butt female of another element, and an annular seal integrated into said female butt. The invention also relates to a device for implementing this method.

 It is known, for example from French patent applications n 73 37 907/2 158 977 and n 82 15 084/2 512 393, to provide such hollow elements, in particular concrete pipe elements, with a gasket. sealing integrated in the female end during the molding of the element. According to these documents, the seal has an inner sealing part and a fixing part which projects outwards on the sealing part and which is embedded in the concrete of the female end piece. It is also proposed by these documents to associate with the seal an annular molding and protection element which has the purpose of reserving, behind the seal, during molding, a clearance receiving the male end during of the connection, and to protect this clearance against any fouling until the time of the connection which is made after removal of the said molding and protection element.

 Still according to these two documents, the seal and the molding and protective element associated with this seal are, before molding, placed on a forming ring which is intended to mold internally the female end of the 'hollow element whose outer surface and the inner surface are molded by an outer part or mold shell and an inner part or mold core.

 This method of integrating a seal and, where appropriate, a molding and protection element at the female end of a hollow element has proven its worth on section concrete pipe elements. circular, oval or the like, that is to say elements having internally, around their entire periphery, a concave curvature. Indeed, in this case, the sealing gasket and the possible molding and protection element are put in place on a forming ring having externally, around its entire periphery, a convex curvature, and this gasket and the element molding and protection are thus plated by their only tension effect on the forming ring, around the entire periphery of the latter.

 There are, however, hollow molded elements, for example of concrete such as elements for technical galleries, elements for vaults, etc. which internally have a transverse square, rectangular, ovoid or similar profile comprising rectilinear parts or even parts. convex, which requires, for molding the female end, a forming ring having an external transverse profile having rectilinear parts or even concave parts. However, it is not possible to maintain a seal and possibly a molding and protection element correctly plated on such a forming ring by the sole tensioning effect of the seal and of the molding and protection element. Therefore, it is not possible to integrate in this way to the female end of such a hollow element a seal and a molding and protective element.

 This is the reason why, at the present time, such hollow elements are, with a view to the sealed connection of their ends, fitted with a seal added after molding on the outside on their male end and fixed for example by gluing on this about. However, such a seal attached externally to a male butt is not protected, so that it is not only subjected to the action of the weather until the element is installed, but also and above all risks being mechanically damaged and soiled during storage and transport as well as during installation of the element. In addition, materials used for such seals often contain waxes which, in particular under the effect of sunlight, migrate to the surface, which compromises the bonding of the seal on the male end. in place of a joint on large elements is long and expensive. Finally, it is difficult to apply a uniform layer of glue all around the male end of such elements.

 It therefore turns out that the usual embodiments for providing hollow elements such as concrete pipe elements with a seal are not satisfactory when said hollow elements have an internal profile comprising one or more rectilinear parts or convex.

 The present invention relates to a manufacturing method making it possible to provide such hollow elements having an internal transverse profile comprising one or more rectilinear or convex parts, with a seal integrated into the molding with the female end so that this seal is perfectly protected. The invention further relates to a method for the manufacture of such hollow elements making it possible to integrate into the female end of these elements not only a seal, but also a molding and protective element reserving a clearance behind said seal sealing and protecting this clearance until the fitting of a male butt into this female butt. Finally, the invention relates to a device for the manufacture by molding of such hollow elements with incorporation into the female butt, during molding, a seal and, if necessary, a molding and protective element.

 According to the method according to the invention of manufacturing by molding of hollow elements such as concrete pipe elements each comprising at least one female butt for their connection by fitting the male end of an element in the female butt of another element, and an annular seal integrated into said female end, said seal is, for its integration, placed before the molding of the element on a forming ring used to mold internally the female end of the latter. According to the invention, at least in the non-convex parts of the external transverse profile of the forming ring, said sealing gasket is pressed against the forming ring.

 Thanks to this action of the depression on the seal, the latter is perfectly held on and pressed against the forming ring, even in the straight, even concave parts of the external transverse profile of this ring during molding, allowing thus obtaining a hollow element with a female butt end internally comprising a perfectly integrated seal.

 To obtain a female butt end further comprising an annular removable molding and protective element reserving an annular clearance behind the seal, said molding and protective element is placed, prior to molding the element, on the ring forming device used to mold the female end of the latter internally. To ensure correct maintenance and plating of this molding and protection element on the forming ring, said molding and protection element is also pressed, at least in the non-convex parts of the external transverse profile of the forming, by vacuum against the forming ring.

 Preferably, the depression is reacted from the inside of the forming ring through holes in the latter on the seal and, if necessary, on the molding and protective element arranged externally on the ring. forming.

 The device for implementing the method according to the invention for manufacturing by molding hollow elements comprises a forming ring used to mold the female end of the element internally and to receive a seal for the purpose of integration of the latter to the female end. According to the invention, said forming ring comprises, at least in the rectilinear or concave parts of its external transverse profile, in the zone intended to receive said seal, holes making it possible to act from the interior of said ring a depression on the exterior of said ring for the plating of the seal against the forming ring.

 In the context of the invention, it is possible to provide, for the seal, at least one row of holes on each straight or concave part of the external transverse profile of the forming ring.

 However, according to a preferred embodiment of the invention, the forming ring comprises, in each straight or concave part of its external transverse profile, at least one external groove extending substantially over the length of said straight or concave part. , a single hole being provided in the forming ring to open into said groove for the application of vacuum in said groove, for the vacuum plating of the seal against said straight or concave part of the ring forming.

 For the reintegration also of an annular molding and protection element at the female end, the forming ring also comprises holes and, where appropriate, grooves also in the zones intended to receive this element in the or the straight or concave parts of its external transverse profile.

Referring to the appended schematic drawings, several more illustrative and nonlimiting embodiments of the invention will be described below in more detail; on the drawings:
Figure 1 is an external view of two pipe elements of rectangular section, before their connection by interlocking their male and female ends;
Figure 2 is an end view of one of these pipe elements, female about side;
Figure 3 is a section on a larger scale along 111-111 of Figure 2, showing the female end of this element with the seal and the molding and protective element incorporated;
Figure 4 is a schematic partial section of the lower part of the device for manufacturing a pipe element according to the invention;
Figure 5 is a partial section, on a larger scale of the forming ring of the device of Figure 4;
FIG. 6 schematically represents the arrangement of the depression grooves on a one-piece forming ring of rectangular shape;
FIG. 7 schematically represents the depression grooves on a one-piece forming ring of ovoid shape;
FIG. 8 schematically represents the arrangement of the depression grooves on a rectangular forming ring formed from assembled segments.

 As illustrated in FIGS. 1 and 2, hollow elements 1 of substantially rectangular internal profile which may be, for example, pipe elements or technical gallery elements in concrete each have at one end a male butt 2 and at the opposite end a female butt 3 allowing the connection of the elements 1 by fitting the male end 2 of an element 1 into the female end 3 of another element 1.

 According to Figure 3, in order to ensure the tightness of this connection, an annular seal 4 is incorporated into the female end 3 of the element 1, over the entire inner periphery of this about. The seal 4 comprises, in known manner, an inner sealing part 5, and an anchoring part 6 which projects outwards on the sealing part and which is embedded in the concrete of the female end piece 3 .

 Furthermore, an annular element 7 for molding and protection is incorporated in the female end piece 3, behind the seal 4. This element 7 which may, for example, be made of a cellular plastic material such as expanded polystyrene is intended to reserve, behind the joint 4, a clearance 8 receiving the male end 2 of another element when the male end fits into the female end 3 of the element l. The element 7 which is removed from the female end 3 only at the time of the fitting of the male end thus protects the clearance 8 by preventing any penetration of foreign bodies in this clearance.

 Such seals and molding and protective elements incorporated into the female end of a hollow molded element, for example of concrete, as well as their mode of incorporation into such a female butt, are known per se from French patent applications Nos. 2,977 and 2,512,383.

 According to FIG. 4, this known mode of incorporation consists in the fact that for the molding of the hollow element, a mold is used composed of an outer part or mold casing 9 and an inner part or mold core 10, arranged vertically and concentrically one inside the other, as well as a lower forming ring or base ring 1 1 intended to mold 11 female end of the hollow element. The seal 4 and the molding and protection element 7 are placed on this forming ring 11 while being held there by their own tension. Concrete is then introduced into the space delimited by the two mold parts 9 and 10 and the forming ring 11, so that the seal 4 and the molding and protective element 7 disposed on the ring 11 are incorporated into the female end. At the upper end of the mold, a pressing element (not shown) is pressed between the two mold parts 9 and 10 to form the male end.

 This known mode of incorporation is satisfactory for hollow elements whose internal transverse profile only comprises concave parts, for example elements of circular, oval, elliptical, etc. internal profile, but is not applicable to hollow elements whose the internal transverse profile comprises rectilinear parts or convex parts, for example elements of square or rectangular profile. Indeed, the seal 4 and the element 7 of molding and protection cannot be correctly pressed, by their tension, against the corresponding rectilinear or concave parts which the forming ring must include.

 To allow perfect sealing of the seal 4 and of the element 7 for molding and protection against the forming ring 11, even in the rectilinear or even concave parts of the arch 11, it is provided, according to the invention, to ensure this vacuum plating at the location of said parts.

 To this end, as shown in FIG. 5, the forming ring 11 comprises, in the zone receiving the seal 4 and in the zone receiving the element 7, at the location of said rectilinear or concave parts, holes 12 making it possible to create from the interior of the ring 11, outside of the latter a depression by which the seal 4 and the element 7 are perfectly pressed against the exterior surface of the ring 11. For this purpose, the holes 12 can be connected, inside the ring 11, as shown very diagrammatically by fittings 13 and hoses 14 to a vacuum source 15, by means of a valve 16. Preferably, the source of vacuum can include a vacuum pump working on a vacuum tank, a quick connection can be provided between the tank and the pump.This tank allows to provide a high flow rate at the start of the application for tackling, despite the use of a pomp e reduced flow.

 n thus suffices, after having put in place the seal 4 and the element 7 on the forming panel 11, to open the valve 16 to establish at the location of the holes 12, a depression under the effect of which the seal 4 and element 7 are pressed against the ring 11 either directly by this depression, or only after having been applied for example manually against the ring 11, in particular in the concave parts of the internal transverse profile of the latter. Then, the molding of the hollow element with incorporation of the seal 4 and of the element 7 can be done in the usual way.

 It is also recognized in Figure 5 that the holes 12 through which a depression can be established outside the ring It can advantageously lead into grooves 17 formed in the ring 11 in the straight or concave parts of the outer transverse profile of Lap valve II in the areas receiving the seal 4 and the element 7. These grooves 17 allow the depression to act over the entire length of the said parts, thus producing a more effective plating effect, with a lower depression, than the holes alone 12.

 According to FIG. 6, which schematically represents the substantially rectangular external profile of a one-piece forming ring 11, a groove 17 extends at least by a seal over the entire length of each rectilinear part of this rectangular profile.

 Similarly, in FIG. 7 which represents the external transverse profile of an ovoid forming ring 11 with two rectilinear parts, a groove 17 extends over the entire length of each of said two rectilinear parts.

 In the case where, as is known per se, the forming ring It is assembled from rectilinear segments 11a and curved segments 1 lb to constitute for example a rectangular forming ring as illustrated in FIG. 8 , each straight segment 1a may comprise at least for a seal a groove 17 which can be connected to a source of vacuum.

 It is thus sufficient, after having put in place the seal 4 as well as, if necessary, the element 7 for protection and molding on the forming ring 11, to apply the vacuum to the grooves 17 so that the seal d the seal (and, where appropriate, the molding and protective element) is (are) either directly pressed (s) by the depression against the straight or concave parts of the external profile of the forming ring, or pressed against these rectilinear parts after having been applied to them manually.

 Although the invention has been described above in its preferred application to the manufacture of hollow concrete elements, it is also applicable to the manufacture of hollow elements by molding from other materials.

 Furthermore, the rectangular and ovoid shapes of these hollow elements and their forming rings are only illustrative examples, the invention being applicable to the manufacture of elements having any other internal transverse profile comprising rectilinear or even convex parts.

Claims (9)

 1. A method of manufacturing by hollow elements (1) such as concrete pipes, each comprising at least one female butt (3) for their connection by fitting a male butt (2) of an element in a female end of another element, and an annular seal (4) integrated into said female end, said seal being, for integration into an element, placed before the molding of this element on a forming ring (11) for internally molding the female end of this element, characterized in that at least in the non-convex parts of the external transverse profile of the forming ring, the seal is pressed against vacuum Forming lap.  2. Method according to claim I, for the manufacture of hollow elements further comprising an annular element (7) for molding and protection incorporated in the female end, behind the seal, said element also being placed on the forming ring prior to the molding of hollow element, characterized in that said molding and protective element is also pressed, at least in the non-convex parts of the external transverse profile of the forming ring, by depression against said forming ring.  3. Method according to claim 1 or 2, characterized in that the depression of the interior of the forming ring is acted through holes (12) of the latter on the seal and, the where appropriate, on the molding and protective element disposed externally on the forming ring.  4. Device for implementing the method according to claim 1 or 3, comprising a forming ring (11) for internally molding the female end of the hollow element and to receive a seal (4) in view of the integration of the latter to the female end, characterized in that said forming ring comprises, at least in the rectilinear or concave parts of its external transverse profile, in the zone intended to receive said seal, holes (12) making it possible to act from the interior of said ring a depression on the exterior of said ring for the purpose of pressing the seal against the forming ring.  5. Device according to claim 4, characterized in that the forming ring comprises at least one row of holes (12) on each straight or concave part of its external transverse profile.  6. Device according to claim 4, characterized in that the forming ring comprises, in each rectilinear or concave part of its external transverse profile, at least one external groove (17) extending substantially over the length of said part straight or concave, and a hole (12) opening into said groove.  7. Device according to claim 4 for implementing the method according to claim 2 or 3, characterized in that said forming ring further comprises, at least, in the rectilinear or concave parts of its external transverse profile, in the zone intended to receive said annular molding and protection element, holes (12) making it possible to act from the interior of said ring a depression on the exterior of said ring with a view to pressing said annular element against the forming ring  8. Device according to claim 7, characterized in that the forming ring has at least one row of holes (12) on each straight or concave part of its external transverse profile.  9. Device according to claim 7, characterized in that the forming ring comprises in each rectilinear or concave part of its external transverse profile, at least one external groove (17) extending substantially over the length of said rectilinear part or concave, and a hole (12) opening out said groove.