FR2599667A1 - Process for producing a hollow profile made from extruded plastic having an incorporated reinforcement, device for its implementation and hollow profile thus obtained - Google Patents

Abstract

PROCEDURE FOR MAKING A HOLLOW PROFILE WITH BUILT-IN REINFORCEMENT, DEVICE FOR ITS IMPLEMENTATION, AND HOLLOW PROFILE THUS OBTAINED. THE HOLLOW PROFILE WITH BUILT-IN REINFORCEMENT IS MADE BY EXTRUSION. THE REINFORCEMENT 9 IS MADE FROM A STRIP OF MATERIAL 4, FOR EXAMPLE OF WHITE IRON, WHICH IS PASSED THROUGH A ROLLER PROFILING SYSTEM 5, 6, 7, TO OBTAIN A TUBE. A SPREADING STATION 8 ELASTICALLY ENCLOSES THE SLOT DEFINED BY THE TWO EDGES OF THE BAND, TO ALLOW THE INSERTION 9 INTO THE FRAME 9 A HOLLOW FIXED CHUCK 11. A CLOSING SYSTEM 12 ASSOCIATED, FOR EXAMPLE, WITH A WELDING STATION OF THE EDGES, ENSURES THE DEFINITIVE SHAPING OF THE TUBULAR REINFORCEMENT 9, BEFORE ITS PASSING AGAINST THE INJECTION CHANNELS ASSOCIATED WITH A GROUP OF EXTRUDERS 15, 16, 17. THUS CAN BE APPLIED TO THE INTERIOR AND TO THE 'EXTERIOR OF THE REINFORCEMENT 9 SEVERAL LAYERS OF HARDENABLE PLASTIC MATERIAL, PREFERABLY MIXED WITH FIBERS. THE LAYERS APPLIED LASTLY ARE PREFERREDLY IMPERMEABLE TO GAS.

Description

The present invention relates to a method for producing

  a hollow profile with embedded reinforcement, by introducing into an extrusion head an elongate reinforcing reinforcement, to then embed this reinforcement in a curable syntactic material which is injected all around the reinforcement.

  The aim is also to

  the application of the method, as well as the reinforced hollow section thus obtained.

  It has long been known to produce hollow sections incorporating a reinforcement reinforcement, for

  to increase the tensile strength as well as the bending stiffness, particularly when it is relatively soft hollow sections such as, for example, in the case of a hollow profile made of plastic by injection.

  Since a hollow profile is normally closed on all sides, the only kind of embedded reinforcement that could be used until now was obtained from a strip of material or from a wire. or a bar of material, by introducing this reinforcement in an extrusion head, opposite a system of channels

  injection, to surround this reinforcement of plastic material injected on all sides.

  But there is also an important demand for reinforced hollow sections, comprising an embedded reinforcement which consists not only of reinforcement strips or reinforcing rods but which is also previously shaped to present a configuration. ana30 logs to that of the hollow profile, to strengthen it in a much more efficient way. For example, it is desirable for a hollow section of

  circular section, and therefore tubular in shape, to provide an embedded reinforcement which is also tubular, to obtain a reinforced hollow section having a particularly high mechanical strength.

  The object of the invention is to provide a method for producing reinforced hollow sections of the type in question, this process making it possible, if necessary, to incorporate reinforcements in the hollow profile which have relatively complex cross-sections, by embedding this reinforcement in the constituent material. of the hollow profile, in order to obtain for it mechanical qualities particularly high in its tensile strength and flexural stiffness.

  The invention also proposes to provide a device for applying the method in question, which makes it possible to continuously produce such a reinforced hollow section. And the invention also relates to the reinforced hollow section thus obtained.

  According to the invention, the method of the kind defined above for producing reinforced hollow sections, by introducing into an extrusion head an elongated reinforcement, and by injecting a curable synthetic material all around this reinforcement, is characterized in that it comprises, in addition, the following operating phases: a) the reinforcement to be incorporated in the hollow section is made from a band of material provided with holes, which is shaped by making it passing to a roller profiling station, to give it a cross section of defined profile, such that the longitudinal edges of the frame thus shaped are closer side by side or in contact with each other; b) elastically deforming the frame thus shaped, by widening, to create a slot-shaped opening between the longitudinal edges close-side by side or in contact with each other; c) introducing a fixed mandrel into the slot-shaped opening; d) closing the slot-shaped opening of the frame that had been enlarged; e) the longitudinal edges are fixed to one another so that they are brought together again side by side or in contact with each other; f) the reinforcement is then passed through a mechanical guiding system associated with the extrusion head; g) a number of layers of a synthetic material are subsequently extrusion-coated onto the reinforcing reinforcement, by bringing this material both from the outside, through a system of injection channels, and through the interior through the fixed mandrel, which has a hollow body for this purpose. Thanks to the process according to the invention, it is possible, for example, to produce a tube of synthetic material comprising an incorporated tubular reinforcement embedded in the material of the tube and completely surrounded by this material. Such a tubular section can withstand a relatively high internal pressure, while having a very interesting lightness, and a particularly high resistance with respect to

  erosion, so that such a tube can be used for a wide variety of applications, such as, for example, for hot and cold water pipelines.

  To obtain on the reinforcing reinforcement a particularly regular layer, according to the invention, it is intended to straighten the strip of material used to make the reinforcement, by passing it through a straightening station before it is shaped. in the roller profiling station. It is convenient to take the web material in a feed reel which is unrolled progressively to ensure the continuous manufacture of a hollow spun yarn made by extrusion. To make the armature incorporated in the hollow section, starting from a strip of material, such as a strip of thin sheet, for example, provided with a series of holes. The longitudinal edges of this strip of material may have protruding hooking projections and hooking notches corresponding to the projections, so as to make it possible to fix one to the other,

  by hanging, the edges of the strip of material.

  The longitudinal edges of the strip of material can also be welded to one another.

  The method according to the invention can also be carried out by applying several layers to the embedded reinforcement, both outside and inside thereof.

  The invention thus provides for applying on the inner face of the armature a first layer of plastic material, by causing this material to arrive by means of a system of injection channels arranged outside the armature; the plastic material then passes through the holes of the frame, to reach the inside of the frame where it is applied and shaped by the fixed mandrel. It is advisable to make the same plastic material with a first outer layer and a first inner layer, and then a second outer layer and a second inner layer made of the same plastic material can also be applied. Advantageously, the first two layers may consist of a mixture of plastic and fibers, in particular a mixture of plastic and wood fibers, while the second outer layer and the second inner layer are advantageously made with a gas impermeable synthetic material, which thus serves as a barrier. It is thus possible to obtain a hollow profile with several layers, preferably used to make pipes for

  gases or liquids, such as hot and cold water pipes in particular.

  The cross section of the hollow profile conforms to

  the invention may be circular or square, or any other form.

  The invention also relates to a device for applying the method that has just been described, to produce a hollow section with embedded reinforcement. According to the invention, this device is characterized in that it comprises: an extrusion machine provided, at its input end, with a straightening station, for straightening a strip of material; a roller profiling station, disposed after the straightening station, and provided with several pairs of rollers, which may be angularly offset from one another if necessary; an enlargement station, disposed after the roll forming station, to widen the armature after it has been shaped, by deforming it elastically so as to reveal a longitudinal slot-shaped opening therein; a fixed mandrel adapted to be introduced into the slot-shaped opening of the armature; a closing station, disposed after the widening station, for closing the armature previously brought to its final transverse profile, a guiding station, arranged after the closing station, and comprising a plurality of distributed guide members 10 around the armature and resting on it, to guide it in a determined position;

  and an extrusion head, provided with a plurality of injection channels arranged one after the other in the longitudinal direction, and facing which is disposed the head 15 of the fixed and hollow mandrel which is associated with the head extrusion.

  Precise and accurate dimensions can be obtained for the hollow profile thus produced in accordance with the invention, by guiding the fixed mandrel by sliding it on the internal face of the reinforcing reinforcement,

upstream of the injection channels.

  The guiding system provided in the device according to the invention is designed so as to guide and maintain the reinforcing armature in the correct position, practically without any wear. For this purpose, the system in question comprises guide members constituted by rotating discs, in the form of gear wheels, whose teeth are evenly distributed around the periphery of the discs, and adapted to engage in the holes of the frame of ren30 strong. By thus taking support on the armature, the organs of

  guiding it in the correct position and guiding it very precisely to allow it to move forward.

  According to the invention, the hollow profile made of plastic material having an embedded reinforcement is characterized in that it is produced according to the method and by means of the

  device that has just been indicated.

  An embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings, in which: FIG. 1 is a schematic side view of an extrusion machine which has the features provided in the invention; Fig. 2 is a partial section of the extrusion head; Fig. 3 represents a piece of the strip of material used to make the reinforcing armature; and 4 is a side view of a gear disk, which is used in the guide station of the

extrusion machine.

  FIG. 1 is a diagrammatic side view of an extrusion machine according to the invention, designated by the general reference number 1. This extrusion machine makes it possible to carry out the process according to the invention. invention,

  to continuously produce reinforced hollow sections.

  The extrusion machine 1 is provided with a supply spool 2, on which is rolled a strip of material 4 used in manufacture, and there is shown a piece in FIG. 4. In the embodiment considered by way of example, the strip of material 4 is constituted (Fig; 3) by a sheet metal strip having a large number of holes 28, arranged side by side in rows in the direction of the length of the band. The outer edges of the material web 4 have latching projections 30 and

  notches of attachment 29 of corresponding profile.

  The material web 4 of the extrusion machine of FIG. 1 passes first to a straightening station 3, in which the strip of material is exactly straightened into a flat sheet of metal with no corrugations. At the exit of the straightening station 3, the strip of material passes into a profiling station located in the zone AB-CD, provided with several pairs of rollers 5, 6, 7 which serve to give the strip

  of material 4 a transverse profile of desired shape. The pebbles of profiling rollers 5, 6, 7, which cooperate and can be angularly offset relative to each other, so as to achieve in the band of various material rounded parts. The strip of material coming out of the pro-

  Spinning at the location of the plane CD constitutes a completely shaped armature, and which, in the case of the embodiment considered by way of example, is presented as a round tube. For the shaping of the reinforcing armature, it is always arranged so that two longitudinal edges, respectively bearing the teeth-shaped hooking protrusions 30 and the hooking notches 29 of corresponding profile, are facing facing or in contact with each other. The tubular reinforcement thus shaped then passes into an enlargement station 8 (plane EF), where the tubular reinforcement undergoes an upe profile. purely elastic deformation, to create a longitudinal slot between its two longitudinal edges. In the zone between GH and EF, the longitudinal slot thus formed in the tubular reinforcement 15 serves to penetrate inside it a fixed mandrel 11, which extends to the outlet end of

the extrusion head 14.

  The tubular reinforcement 9 then arrives at a closing station 12 (plane GH), where the two longitudinal edges are again brought closer together, to remove the slot and pass the one over the other the two longitudinal edges, so as to engage in each other the projecting hooking teeth 30 and the corresponding hooking notches 29. Thus, the frame is completely prepared to be introduced into a guide station 13, which comprises a number of rotating discs in the form of gear wheels 31 regularly distributed around the tubular reinforcement. It is shown in FIG. 4 one of these discs 31, which have at the periphery projections in the form of teeth 32, between which there is an interval which corresponds to the (longitudinal) gap of the holes of the material strip 4 used to make the reinforcement These guide disks in the form of toothed wheels have their principal planes parallel to the longitudinal axis of the extrusion machine 1, and it is thus possible to provide thus several groups of disks arranged one behind the other. in the longitudinal direction, with an appropriate distribution around

  of the tubular reinforcement 9, so as to center accurately

  the tubular reinforcement 9 in a position determined at the location of the guide station 13, to introduce into the extrusion head 18 the tubular frame 9 and exactly centered. With the help of the guide wheels in the form of wheels 31, the friction at the location of the guide station 13 is almost completely eliminated, in a particularly advantageous manner, thus ensuring extremely low wear.

at the same place.

  The rows of holes arranged in the longitudinal direction may have an offset with respect to one another in the same direction, whereby the simultaneous movement of the entry and exit of the teeth of the guide discs can be avoided. 31, in the holes of the frame; and these movements, which then take place partly at the wrong time, make it possible to effectively suppress the shaking and

  vibrations of the armature thus driven forward.

  The tubular reinforcement 9 coming out of the guiding station 13 enters an extrusion head 18, which is shown schematically in partial section in FIG. 2, on an enlarged scale. The extrusion head 18 is constituted by a plurality of disc-shaped members 33, 14 held together in the longitudinal direction by suitable fasteners (not shown). The extrusion head contains a first injection channel 19, of annular shape, arranged around the frame 9 and which communicates with an obliquely oriented injection slot. This annular injection channel 19 makes it possible to send a certain flow of plastic material to the wall of the tubular reinforcement 9, so as to penetrate a part of this plastic material inside the tubular reinforcement 30 to through the holes 28 of the armature (Fig. 3). 2, schematically the fixed mandrel 11 that can be introduced inside the tubular reinforcement 9, facing the inner face of the wall of the armature, in the area of the

guiding station 13.

  On the side of its anterior end, the fixed mandrel 11 has a profiled annular groove 23 ', which surrounds the mandrel and in which can penetrate the plastic material from the injection channel 19 and which has passed through the holes 28 of As a result of the profile of the fixed mandrel 11 which is progressively widening, the plastic contained in the groove 23 'forms an inner layer 24 against the wall of the armature 9. ] when an outer layer 23 is formed at the same time on the fact: external of the same wall, and is joined to the first layer 24 by the plastic material that passes through

  the holes 28 of the tubular frame 9.

  In the direction of advance movement of the tubular reinforcement 9, a second annular injection channel 20 is disposed following the first annular channel 19, to deposit

  a second outer layer 25 on the first outer layer 23 of plastics material.

  Through the inside of the fixed mandrel 11, which is hollow, a flow of plastics material is introduced through injection channels 27, to apply a second inner layer 26 to the first inner layer 24, and this is the profile the end 21 of the fixed mandrel 11 which determines the final shape of this second inner layer. As

  it can be seen in FIG. 2, the outer diameter of the end 21 is a little smaller than the diameter of the body of the fixed mandrel 11 in the area of the guide station 13.

  Thus, a reinforced hollow section, which exits through the left end of the extrusion machine, and this hollow profile, not only can be made in any desired length, as desired, but it has, in addition, properties well This hollow profile can be made with a particularly thin wall made of several outer layers and several inner layers. The transverse profile of the reinforcement disposed in this profile corresponds to the transverse profile of the hollow profile itself, which makes it possible to use this reinforcing reinforcement very effectively, in order to obtain a high mechanical strength, in particular

as for flexural stiffness.

  It goes without saying that the extrusion head 18 can be made with more than two injection channels 19 and 20, so as to obtain a multi-layer structure comprising more than four layers associated with an embedded reinforcing reinforcement. The arrangements that have been indicated above make it possible, moreover, to obtain an advantageous advantage, because it is possible to ensure in a very precise manner, all around the profile and over the entire length thereof, the constant thickness of each layers so as to obtain a hollow profile having constant mechanical properties in all directions about its axis. This advantage is particularly advantageous when the hollow profile is intended to serve as a pipe for a gas or a high-pressure liquid. It is obvious that, to achieve the layers that cover the reinforcement, one can use various kinds of plastics, various mixtures of plastics and reinforcing fibers, or various barriers

  sealing of specific nature, based on plastic materials.

  In a particularly advantageous embodiment, it is thus possible to use a copolymer of ethylene and of vinyl alcohol for the inner layer 26 and / or for

  the outer layer 25, so that these layers then act as gas-tight retaining layers.

  It should be noted that the extrusion process according to the invention, as just described, is in no way limited to the only case of a built-in frame of circular section. In accordance with the invention, it is also possible to produce hollow sections of square section or of rectangular section, or hollow profiles having any other cross section, operating from

the same way.

  In the extrusion machine 1 shown in FIG. 1, the flow rate of three extruders 15, 16 and 17 is used in principle. But it is obvious to one skilled in the art that more can be used, and For example, to associate the extruder 15 with a fourth extruder, in order to deposit from the inside a special covering layer on the layers already deposited successively, by operating through a second passage formed inside the body of the fixed mandrel.

11.

  Finally, the closing station 12 may also be constituted by a welding station, downstream of which is disposed a grinding station, for welding to one another the two longitudinal edges of the tubular reinforcement, after the implementation. final for10 me of it. In this case, it is sufficient, most

  In the meantime, it is necessary to make a spot-welded joint spaced at a given interval, and not a continuous-line welded joint.

  The material strip 4, used to make the reinforcement incorporated, can be tinplate, or sheet steel, or even copper or any other metal, but this strip can also be constituted by a mesh of frame or by

a stiffened fabric.

  It is also possible, thanks to the process according to the invention, to produce a hollow section section of plastic.

  relatively large transverse, reinforced by a built-in frame completely embedded in the plastic material.

  It is also possible to use this embedded reinforcement to transmit electrical signals, so that the hollow section produced according to the invention can fulfill a dual function, firstly as a transport pipe for a gas or a liquid, and secondly as an electrical conductor, to ensure the passage of electrical signals or

  an electric supply current.

  All the technical features indicated in

  the description and shown in the drawings are important for the invention.

Claims (24)

  1. A method for producing reinforced hollow sections, comprising introducing into an extrusion head an elongated reinforcement, and injecting a curable synthetic material all around this reinforcement, characterized in that: a) the reinforcement is made up to be incorporated in the hollow profile from a web of material (4) provided with holes (28), which is shaped by passing it through a roller profiling station (5, 6, 7), to give it a trans-versal section of determined profile, such that the longitudinal edges of the frame thus shaped are brought together side by side, or in contact one against the other; b) elastically deforming the frame (9) thus shaped, widening it to create a slot-shaped opening between the longitudinal edges close side by side, or in contact with each other; c) introducing a fixed mandrel (11,21,27) in the slot-shaped opening thus created; d) closing the slot-shaped opening of the frame (9) which had been enlarged; e) the longitudinal edges are fixed one to the other so close again side by side, or in contact with each other; f) the armature (9) is then passed through a guiding system (13) associated with the extrusion head (18); g) a plurality of layers (23, 24, 25, 26) of a second layer are subsequently extruded onto the reinforcing reinforcement (9).   synthetic material, which is made to arrive both externally, by a system of injection channels, and internally through the fixed mandrel (11,21,27).   2. Method according to claim 1, characterized in that the strip of material (4) is straightened before being shaped in the roller profiling station (5, 6, 7), making it   move to a recovery position (3).   3. Method according to one of claims 1 or 2, characterized in that the strip material (4) is taken from a supply reel (2) which is unrolled as and when required. 2.5 9 9 U57 re.   4. Method according to one of claims 1 to 3, characterized in that a strip of material (4) consists of a thin sheet metal strip, provided with a number 5 rows of holes.   5. Method according to claim 4, characterized in that the longitudinal edges of the strip of material (4) are   provided with hooking protrusions (30), and latching recesses (29) of profile corresponding to that of said sail10 lees.   6. Method according to one of claims 1 to 4, characterized in that is fixed to one another by welding the edges   longitudinal reinforcement reinforcement (9) after the form of it.   7. Method according to one of claims 1 to 6, characterized in that applies to the armature (9) a first   inner layer (24) of synthetic material fed by an outer injection channel (19), which material passes inside the armature (9) through the holes (28) thereof, for find formatting by the fixed chuck   (11,21,27) and applied by the mandrel against the inner face of the frame (9).   8. Process according to claim 7, characterized in that the first outer layer (23) of synthetic material and the first inner layer (24) of synthetic material are made of the same material, and in that (9) a second outer layer (25) and a second inner layer (26) which are formed of the same synthetic material.   9. Method according to claim 8, characterized in that the synthetic material of the first inner layer (24) and the first outer layer (23) is different from the synthetic material of the second inner layer (26) and of the second outer layer (25).   10.Procédé according to claim 9, characterized in that the synthetic material of the first inner layer (24)   and the first outer layer (23) is based on a mixture of   age of fibers and plastics.   11. Process according to claim 10, characterized in that the mixture of plastics material and fibers comprises wood fibers. 12. Process according to one of claims 8 to 11, characterized in that a gas-impermeable material is used.   for producing the second outer layer (25) and / or the second inner layer (26).   13. Process according to claim 12, characterized in that the gas-impermeable material is based on a copolymer ethylene vinyl alcohol.   14. Process according to claim 1, characterized in that the strip of material (4) is shaped in a system   roller profiling, to give it a transverse section 15 of circular or square shape.   Method according to claim 4, characterized in that a strip of material (4) is used, which has several rows of holes arranged side by side in the lengthwise direction of the strip, and in that the holes of one of the longitudinal rows can be shifted in the direction   the length of the strip relative to the holes of another row.   16. Device for implementing the method according to   one of claims 1 to 15, comprising means for introducing a reinforcing reinforcement in an extrusion head   in which injection channels are provided, for coating the reinforcement with a synthetic material injected around it; characterized in that it comprises: an extrusion machine (1) provided at its input end 30 with a straightening station (3) for straightening a strip of material (4); a roller profiling station, arranged after the straightening station (3), and provided with several pairs of rollers (5, 6, 7) which can, if necessary, be angularly offset relative to one another ; 5667 a widening station (8), arranged following the roller profiling station, to widen the armature (9) after shaping, deforming elastically to reveal a longitudinal opening shaped slit; a mandrinfixe (11), adapted to be introduced into the slot-shaped opening of the armature (9); a closing station (12), arranged after the widening station (8), for closing the armature previously brought to its final transverse profile, by fastening the longitudinal edges of the strip to each other; material shaped by profiling; a guiding station (13) arranged after the closing station and comprising a plurality of guiding members (31) distributed around the armature (9) and resting on it to guide it into a position determined; and an extrusion head (18), provided with a plurality of injection channels (19, 20) arranged one after the other in the longitudinal direction, and facing which is disposed the   head (21) of the fixed and hollow mandrel (11,21,27) associated with the extrusion head.   17.Dispositif according to claim 16, characterized in that the fixed mandrel is guided by sliding on the inner face of the reinforcing armature (9), upstream of the channels Injection (19,20).   18.Device according to one of claims 16 or 17,   characterized in that the fixed mandrel has, on its front part, a hollow recessed groove (23 ') which surrounds the body of the mandrel, to receive the synthetic material coming from the outside through the holes (28) of The frame (9).   19.Device according to one of Claims 16 to 18,   characterized in that the fixed mandrel (11) has an end (21) of smaller diameter than the rest of the body chuck.   20. Device according to claim 16, characterized in that the guide members (31) of the guide station (13) are constituted by rotating disks in the form of gear wheels, whose teeth (32) are regularly distributed at the periphery. disks, and adapted to engage   in the holes (28) of the reinforcing armature (9).   21. Device according to claim 20, characterized in that it comprises several groups of rotating discs   (31), arranged one behind the other in the longitudinal direction, and adapted to engage the frame (9).   22. Device according to claim 16, characterized   in that the closing station is a welding station.   23. Hollow profile of plastics material comprising an embedded tubular reinforcement, embedded in the plastics material, characterized in that it is produced in accordance with one of Claims 1 to 22.   24. Hollow section according to claim 23, characterized in that the reinforcing armature incorporated in the   profile serves as an electrical conductor, to ensure the passage of electrical signals and electrical current.