FR2463671A1 - Automated lay=up of hollow reinforced resin profiles - for wind-surfing masts etc. requiring multiaxial stiffness - Google Patents

Abstract

Tubular profiles of reinforced resin are made on a supporting mandrel (1) which is first unwound by continuous crossed helical filaments, then overlaid with filaments (3) parallel to the mandrel surface longitudinally before passing through a hollow sleeve from which woven tubular reinforcement (4) is drawn on to the supported filaments whilst being axially inverted. Used for mfr. of profiles required to combine good filexural, tensile and torsional stiffness, e.g. masts for windsurfing boards.

Description

 The present invention relates to a process for manufacturing reinforced tubular bodies of synthetic material of the type in which reinforcement wires are placed on a mandrel, the reinforcement is impregnated with a material synthetic, preferably thermosetting, and the assembly obtained is hardened to produce the hollow body.

 The tubular bodies obtained according to the invention are advantageously intended to form parts resistant to traction and to torsion, in particular masts of windsurfers, side members, beams and other resistant sections.

 The invention also relates to a device for implementing this method and to the hollow bodies obtained.

 Currently, to make masts of windsurfers in reinforced synthetic material, a glass cloth preimpregnated with a thermosetting resin is rolled on a mandrel and the thermosetting of this fabric is carried out, after which the mandrel is removed. However, the masts obtained have the drawback of not having good resistance either to traction or to torsion. The tests which have been carried out in an attempt to remedy these defects, by modifying the reinforcements, have moreover led to long processes and high cost prices.

 The present invention proposes to remedy these drawbacks and to provide a method of manufacturing reinforced tubular bodies made of synthetic material, which makes it possible to manufacture tubular bodies having a markedly increased resistance both to traction and to torsion, while being very light and using the raw material just necessary. In addition, the invention is proposed to provide such a method which is easy to implement and leads to low cost prices.

 The invention also proposes to provide a device allowing an easy and inexpensive implementation of this process, semi-continuously or even continuously.

 Finally, the invention proposes to provide new tubular bodies reinforced with synthetic material, having increased resistance and longevity and a particularly low cost price.

 The subject of the invention is a method of manufacturing reinforced tubular bodies made of synthetic material, in which an armature is made and an impregnation of the armature to then carry out a polymerization of the assembly obtained, characterized in that the an elongated mandrel is covered with a first sheath formed by a reinforcing braid the strands of which are directed in directions allowing resistance to twisting and crisscrossing in order to give them excellent working cohesion and good transmission of strand forces stranded, that said first sheath is covered with a plurality of longitudinal reinforcing wires by passing the mandrel coated with its sheath through a wire application station, and that the mandrel is then passed , with said first sheath and said wires, through a second braid-shaped reinforcing sheath, so that said second sheath turns over like a thermowell so that its surface originally externally e comes to bear against the mandrel coated with said first sheath and said wires, the assembly covering the mandrel then being intended to be impregnated, then polymerized, as a result of which the mandrel is separated from the tubular body obtained.

 Preferably, and in particular in the case of the manufacture of windsurfing masts, a slightly frustoconical mandrel is used to form a slightly frustoconical tubular body whose shape facilitates the subsequent removal of the mandrel by longitudinal traction relative to the tubular body. If it is a question of manufacturing cylindrical tubes, it may be advantageous to use removable or inflatable and deflatable mandrels in order to facilitate the removal of the laminated tubular body.

 In a particularly preferred manner, in a semi-continuous embodiment of the method, the first sheath, the wires and the second sheath are fixed on an anterior end of the mandrel, the displacement of the mandrel then causing the unwinding of the sheaths and the wires as well as their application and implementation.

 Sheaths and / or prepreg wires can be put in place, but preferably, the first sheath is impregnated after it has been placed on the mandrel, then a further impregnation of the mandrel when it has been coated with its second sheath, this latter impregnation being able to be followed by the winding of a non-adherent strip around the impregnated assembly to ensure conformation and maintenance during polymerization. The establishment of this strip can be advantageously carried out by simple rotation of the mandrel about its axis.

In a particularly preferred embodiment, applicable both to a semi-continuous manufacturing process and to a continuous manufacturing process, the displacement of a mandrel is ensured by pulling its anterior end using the posterior end of the previous mandrel, means then being provided for securing and detaching the mandrels by their ends.

 The sheaths formed by the braids can either have been produced in advance, or be produced on site shortly before their application on the mandrel.

 The invention also relates to a device for implementing this method, said device being characterized in that it comprises a plurality of mandrels, a station for placing a first sheath on a mandrel, a application station of a plurality of wires on the mandrel coated with its first sheath, and an application station of a second sheath on the mandrel coated with the first sheath and said wires, said application station comprising means to bring said second sheath in the opposite direction to the direction of movement of the mandrel, means being further provided for allowing movement of said mandrels through the various stations.

 Preferably, the wire application station comprises, regularly spaced around the axis of movement of the mandrel, a plurality of guide means, such as preferably holes in a plate, ensuring the passage and guiding of the wires. near the mandrel and / or an additional circular comb.

The position for placing the second sheath is, in a particularly advantageous embodiment, placed adjacent to the wire application station and comprises a tubular element on which slides said second sheath, in a direction opposite to the direction in advance of the mandrel, said sheath turning at the end of said tubular element so that its originally external face is applied against the underlying coated mandrel and is "swallowed" by it.

It is particularly advantageous for the longitudinal wires to then penetrate into the gap formed between the mandrel coated with the first sheath and the second sheath being applied so that said wires are initially guided by the surface. external of said second sheath.

 The mandrels, which preferably have a slightly frustoconical shape to facilitate their bending, have ends capable of being connected to each other. Thus one of the ends of the mandrels can advantageously include a thread of reduced diameter, capable of being screwed into a suitable tapping of the opposite end of the adjacent mandrel. Thus the establishment of a mandrel is carried out by simple rotation relative to the previous mandrel already in place. According to a variant, the two mandrels penetrating one into the other are made integral by a pin which passes through holes provided in these mandrels.

The device can also have a means for drawing a mandrel such as for example a carriage.

 In order to move the first mandrel of a train of mandrels, it is also possible to provide an elongated drive part whose posterior end is capable of being fixed to the anterior end of the first mandrel, means, such as for example said carriage being provided for pulling this part.

The anterior end of the mandrels may advantageously include means for fixing the sheaths and / or wires and, for this purpose, this end may preferably have a groove in which it will be possible to tighten, using a or several collars, the anterior ends of sheaths and / or wires.

 The device according to the invention also comprises a hardening station, preferably of thermosetting, and a separation station, preferably located upstream of the hardening station, said separation station allowing, in the case where a succession of mandrels is coated sheaths and wires extending without solution of continuity over this entire succession, to cut the covering before the separation of the different mandrels.

The device according to the invention can also advantageously include impregnation stations suitably arranged, a final impregnation station for the second sheath can advantageously be provided with means making it possible to rotate the mandrel coated with its coating around its axis, said rotation which can also be taken advantage of for the helical application of a strip of non-adhesive material, for example synthetic material, intended to ensure the final forming of the external surface of the tubular body obtained, said strip being removed after polymerization.

 Preferably, it is possible to provide a separation station provided with means for axially locking the tubular body and for extracting the mandrel from the blocked tubular body, using a jack. The mandrel can advantageously have, at one of its ends, a passage for a pin allowing the application of this tensile force.

 In the case of a continuous manufacturing process, the device may also include sheath manufacturing stations arranged in the vicinity of the sheath application stations, said sheath manufacturing stations being produced in a manner known per se, leaving in their center a passage for the train of mandrels.

 In such an embodiment, the movement of the train of mandrels is preferably ensured by means of drive rollers.

The invention also relates to the tubular reinforced bodies made of synthetic material obtained by the method according to the invention, said tubular bodies comprising in particular a first sheath, disposed internally, being in the form of a braid ensuring resistance to torsion, a plurality of more external longitudinal wires ensuring a tensile strength and a second external sheath also in braid, ensuring the surfacing of the body and contributing, if necessary, to torsional resistance, the reinforcements thus formed being taken in hardened synthetic material.

Preferably, the braids are made of fibers or son of glass with size compatible with the impregnation material which is preferably a thermosetting plastic material (polyester, epoxy, phenolic or other resin.).

 The wires can advantageously be made of carbon or high rigidity polyimide.

 According to an advantageous characteristic of the invention, the angle of inclination of the wires of the braid forming the first sheath relative to the axis of the tubular body is less than or equal to 300, the angle of inclination of the wires the braid forming the second sheath being less than or equal to 400.

Other advantages and characteristics of the invention will appear on reading the following description, given by way of nonlimiting example and referring to the appended drawing in which
FIG. 1 represents, in diagrammatic view, an installation of a device according to the invention.

FIG. 2 represents a mandrel according to the invention.

 FIG. 3 represents a tool for pulling a first mandrel.

 Figure 4 shows in elevation a traction carriage.

FIG. 5 represents an end view of this carriage.

 Figure 6 shows, in schematic axial section, the son and second sheath application stations.

 FIG. 7 is a diagrammatic view of a tendering station, oriented as in FIG. 1.

 Figure 8 shows, in a schematic elevational view, a continuous manufacturing installation according to the invention.

FIG. 9 represents a tubular body according to the invention.

 We first refer to Figure 9.

 This figure shows, around a mandrel 1, the reinforcement of the tubular body according to the invention which has a first sheath or internal braid 2, a plurality of longitudinal wires 3 disposed peripherally with respect to this braid 2 and a second sheath or outer braid or facing braid 4. During the formation, the wires 3 keep their place both because of the stickiness of the sheath 2 which has been impregnated and of the tightening carried out immediately at the time of their dep8t on the mandrel 1 by the sheath 4.

The entire frame is impregnated with a resin (not shown) which drowns the frame and which, once the resin has hardened, for example by thermosetting, ensures the cohesion of the tubular body formed.

 We now refer to Figures 1 to 6.

 Referring more particularly to FIG. 1, there is a schematic view of the installation of a device for implementing the method according to the invention. In this figure, a dashed line represents the path followed by the different chucks to the during a cycle. These mandrels have been suitably cleaned and covered with a layer of non-adhesive substance, for example wax, to facilitate subsequent bending. The mandrels 1, thanks to means of transport not shown, arrive successively at a station 5 for installing the first sheath. This positioning of the first sheath 2 can be carried out for example manually by sleeving the sheath on the mandrel or on the contrary by automatic means. Preferably, this positioning station 5 is also impregnated using a slow-catalyzing resin, this impregnation can be carried out manually or by conventional means. The mandrel 1 coated with the sheath 2 is then sent to a station 6 for placing longitudinal wires. If necessary, the mandrel may have been hooked, by its front end, to the rear end of a previous mandrel or else of a pull rod. This hooking can be done manually or if necessary by any hooking means in a hooking station 7a.

 The station for placing longitudinal wires 6 is immediately followed by a station 7 for placing the second sheath.

Between the two stations 6, 7, the front end of the longitudinal wires and / or the second sheath is fixed against the front end of the mandrel so that the displacement of the mandrel causes traction on the wires and / or sheath.

 At the exit from station 7, a separation station 8 is shown making it possible to separate the different successive mandrels which leave station 7 and also, if necessary, to separate the anterior end of the sheaths and wires previously fixed on the anterior end of mandrel.

In 9, there is shown schematically the outward and return path of a means of traction of the train of mandrels, preferably constituted by a carriage. The different mandrels, preferably after having been separated from each other, then arrive at an impregnation station 10 where the mandrel is impregnated with resin. Preferably, the mandrel is rotated about its axis to facilitate this impregnation which can be manual or carried out using any impregnation means.

 Preferably, also at position 10, a strip of non-adherent plastic material, for example ltyloa, is wound on the impregnated mandrel, so as to form a helical peripheral winding covering the underlying assembly. The coated mandrels then arrive at a polymerization or thermosetting station 11 where they remain the time necessary for this operation. They finally arrive at a stretching station 12 where the tubular bodies formed are separated from their mandrel, the helical strip having been, if necessary, removed beforehand. The mandrels are recycled from work center 12.

 Referring more particularly to FIG. 2, we see a mandrel 1 having for example a length of 470 cm and having at its front end a diameter of 3.5 cm and at its rear end a diameter of 4.8 cm, this which gives the mandrel a slight taper. The front end of the mandrel 1 has a threaded extension 13 while the rear end has a corresponding thread 14, so that the front end of a mandrel can be screwed into the rear end of the previous mandrel and therefore connected to this one.

Other attachment means, for example of the pin, bayonet, clip or other type, can naturally be used in place of a screw fastening. The rear end of the mandrel also has a through hole 15 intended for the passage of a mandrel fixing pin on the mandrel shifting station. The front end of the mandrel also has a through hole 16 allowing the passage of a pin for the mandrel is driven by a tractor, for example a carriage. Finally, behind the orifice 16, the anterior end of the mandrel has a groove 17 in which the anterior end of the first sheath, wires can be fixed of, longitudinal reinforcement and the second sheath, for example by means of an adhesive tape or by a clamp.

Preferably, to drive a mandrel or a train of mandrels, a traction tool 18 shown in FIG. 3 is screwed to the anterior end of the mandrel and having a tapping 14 at its posterior end and a groove 19 at its anterior end its attachment to the traction carriage.

 The carriage, which is shown at 20 in Figures 4 and 5, can either be slidably mounted on a rail, or be provided with wheels guided on rails. This carriage 20 is preferably driven, in a manner known per se, by a chain 21 with the aid of a movable pawl 22 capable of coming to engage in the chain 21 or to disengage therefrom for stopping the cart. The carriage 20 carries on its upper face a plate 23 provided with a passage 24 having a diameter allowing the passage of the body of the tool 18. For the attachment of the tool 18, one comes to have on the groove 19 a second movable plate 25 provided with a passage 26 corresponding to the diameter of the groove 19. When the carriage 20 advances, the plate 23 drives the plate 25 which is placed in front and, therefore, it drives the tool 18 and the following mandrel .To ensure the drive, one can also use a pin 27 cooperating with the orifice 16, said pin being secured in any way with the carriage 20.

 Referring to FIG. 6, we can see schematically the two successive stations 6 and 7. The station 6 mainly comprises a transverse plate 28 provided with a central orifice 29 allowing the passage of the mandrel 1 and a plurality of orifices 30 regularly distributed around the central orifice 29 and allowing the passage and the guiding of the wires 3. The latter come from supply coils (not shown) and can preferably be guided between the coils and the orifices 30 by tubes. Preferably, the angle formed by the wires 3 and the geometric axis of the mandrel, in the vicinity of the arrival of the wires, is of the order of 150.

 The station 7 includes a tubular member 31 defining a central passage 32 for the mandrel. This tubular member is coated with the second sheath in braid form 4, suitably accumulated so that the length of the member 31 is sufficiently short. The face of the extensible sheath 4, which is oriented towards the outside on the member 31, is the face which is intended to form the internal face of the sheath 4 once laid, that is to say the one coming in contact with the longitudinal wires 3. It can be seen that at the rear end of the tubular member 32, the sheath 4 turns over to come to bear, by geometric deformation of its diameter, on the mandrel 1 previously coated with the sheath 2 and 3 wires.

The converging part 4a of the sheath 4 preferably tends to take a taper ensuring the guiding and good holding in place of the wires about to be applied to the internal sheath 2. When the entire length of sheath accumulated on the member 31 has been used, the member 31 is preferably replaced by another provided with an accumulated length of sheath.

Referring to FIG. 7, we can see a detail of the rear end of a tendering station 12.

This station has a normally fixed receiving part 33 having a cylindrical extension 3 inside which comes the rear end, free of sheath, of the mandrel 1. Suitable orifices in the extension 33a allow the passage of a pin 54 penetrating into the orifice 15 of the mandrel 1 and immobilizing the latter both axially and in rotation. Furthermore, the rear end of the mandrel 1 is surrounded by a tubular piece 34, the edge of which faces forward is likely to come into contact with the rear end of the tubular body 35 consisting of sheaths 2, 4, wires 3 and polymerized resin, the ends, both anterior and posterior, of the tubular body 35 having been obtained by cutting, on the mandrel, protruding parts of sheaths, wires or resin so as to form blunt ends. A thrust member 36, having fork-shaped extensions 37, passes through the orifices of the part 33, above the cylindrical extension 33a and comes to bear on the rear edge of the part 34. that a jack actuates the member 36 in the direction of the arrow and, consequently, the part 34 pushes the tubular body 35 towards the front of the mandrel, that is to say towards the zone where the taper decreases, which quickly separates the tubular body 35 from the mandrel 1 and allows the latter to be released.

3ien understood, in ~ this case, the tubular body 35 has a conical interior and exterior shape corresponding to the taper of the mandrel.

 We refer to figure 8.

In this figure, there is shown schematically a variant of the device according to the invention allowing advanced automation and continuous manufacturing. We see in this figure a train of mandrels 1 guided by a set of rollers 38 either isolated, or grouped in pairs pushed elastically so as to always ensure the 'guiding of the train of mandrels despite variations in thickness. If necessary, some of these rollers can be powered.

The train successively crosses a station 5 for installing the sheath 2, a station 6 and a station 7. The station for installing the sheath 5 further comprises a conventional rotary assembly 39 which allows local manufacture of the sheath 2 continuously and from which the braiding ring 40 can be seen. Towards its downstream end, the station 5 comprises resin impregnation means with a ring 41 dispensing the resin, a recovery tank 42 and drain rollers 43.

 The train of mandrels then passes into station 6 which is identical to that shown in FIG. 6.

The post 7 is also identical to that of FIG. 6 except for the fact that the sheath or braid 4 is produced on site by a rotary braid making machine 44, comprising a braiding ring 45. A new member for impregnation 46, similar to that of station 5, is arranged downstream. This station is followed by a station 47 composed of a circular plate carrying one or more coils of strips of plastic material 48 which, during the rotation of the plate, helically wind one or more layers of bands around the coated mandrel. The other stations can also be made automatically to be adapted to the production pace.

In the case of continuous manufacturing, it is possible to place the system either horizontally, as shown in FIG. 8, or (if there is sufficient space and arrangement) vertically.

 The invention is particularly applicable to the manufacture of slightly conical tubular bodies intended to form masts of windsurfers. However, it is also possible to produce totally cylindrical tubular bodies using, for example, collapsible or inflatable and deflatable mandrels.

 The inclination of the wires of the braid forming the first sheath is preferably less than or equal to 300, relative to the axis of the tubular body. This inclination is of course the berm for both the wires of the braid which have the step to the right and / them which have the step to the left.

 The inclination of the wires of the second braid is preferably less than or equal to 400.

 By way of example, a tubular body was manufactured comprising a first braid made of glass threads made from 120 spindles of three threads of sized 136x2 roving.

The braid was impregnated with slow-catalyzing polyester.

The first sheath was covered with 60 roving glass wires of 2400 tex, regularly distributed around the perimeter. The outer sheath, which also plays a surfacing role, is made from 120 spindles of 4 x 68x2 glass strands.

The pulling of the mandrel, through the various sheathing and wire positioning stations, is done at a speed of 5 meters per minute. The second sheath was in turn impregnated with polyester, then covered with a winding of strips of polyester film, these strips having been removed after the polymerization.

Claims (10)

R DICATI0NS 1. A method of manufacturing reinforced tubular bodies made of synthetic material, in which an armature and an impregnation of the armature are produced in order to then polymerize the assembly obtained, characterized in that an elongated mandrel is covered with a first sheath formed by a braid of reinforcement, the strands of which are directed in directions allowing resistance to twisting and crisscrossing, which said first sheath is covered with a plurality of longitudinal reinforcing wires by passing the mandrel coated with its sheath through a wire application station, and the mandrel is then passed, with said first sheath and said wires, through a second braid-shaped reinforcement sheath, so that said second sheath turns over like a thermowell so that its originally external surface comes to bear against the mandrel coated with said first sheath and said wires, the assembly covering the mandrel then being intended to be impregnated, then polymerized, as a result of which the mandrel is separated from the tubular body obtained, the mandrel preferably being slightly frustoconical to form a slightly frustoconical tubular body, which facilitates the extraction of the mandrel by longitudinal traction relative to the tubular body.  2. Method according to claim 1, characterized in that one fixes the first sheath, the son and the second sheath on an anterior end of the mandrel, the displacement of the mandrel then causing the unwinding of the sheaths and the son and their setting square.  3. Method according to one of claims 1 and 2, characterized in that one performs an impregnation of curable synthetic material after the establishment of the first sheath on the mandrel, then a new impregnation, followed by winding a non-adhesive strip, after the second sheath has been put in place. 4. Process according to any one of claims 1 to 3, characterized in that the sheaths in the form of a braid are manufactured continuously while scrolling a train of mandrels continuously. 5. Device for implementing the method according to any one of claims 1 to 4, characterized in that it comprises a plurality of mandrels, a station for placing a first sheath on a mandrel, a station applying a plurality of wires to the mandrel coated with its first sheath, and a station for applying a second sheath to the mandrel coated with the first sheath and said wires, said application station comprising means for bringing said second sheath in the opposite direction to the direction of movement of the mandrel, means being further provided for allowing the displacement of said mandrel through the various stations.  6. Device according to claim 5, characterized in that the mandrels have a slightly frustoconical shape, have at their anterior and posterior ends means for fixing against adjacent mandrels, and are provided with an anterior groove for fixing the sheaths and son.  7. Device according to any one of claims 5 and 6, characterized in that it comprises, at the position for placing the wires, a plate provided with a plurality of orifices regularly distributed around an orifice for the passage of mandrels, to guide the wires, while the station for placing the second sheath comprises a tubular element on which the second sheath is sleeved so that said sheath turns in the vicinity of where the wires s 'apply on the first sheath. 8. Device according to any one of claims 5 to 7, characterized in that it comprises a carriage provided with means allowing the fixing of the anterior end of a mandrel or of a mandrel pulling tool, means being provided to drive said carriage.  9. Device according to any one of claims 5 to 8, characterized in that it comprises, for carrying out the mandrel of a frustoconical mandrel, a mandrel station comprising a part capable of holding a posterior end of mandrel to the using a pin passing through a corresponding orifice of said mandrel, a sliding part capable of applying against the rear end of the tubular body disposed on said mandrel, and axial thrust means acting on said sliding part in the direction of the end anterior, of smaller diameter, of the mandrel. 10. Reinforced tubular body of synthetic material obtained by the implementation of the method according to any one of claims 1 to 4, characterized in that the braid son of the first sheath form, with the axis of the tubular body, a angle less than or equal to 300 and that the braid threads of the second sheath form with said axis an angle less than or equal to 400.