FR2507956A1 - METHOD AND DEVICE FOR PRODUCING REINFORCED RESIN HOLLOW ELEMENTS, PARTICULARLY PROTECTIVE HELMETS, AND COMPONENTS THUS OBTAINED - Google Patents

Abstract

The invention relates to a method and a device for producing hollow elements made of reinforced resin, in particular protective helmets and the elements thus obtained. TO PRODUCE HOLLOW ELEMENTS IN RESIN REINFORCED BY WOVEN FABRICS AND / OR NETS, THE EDGES D OF SEVERAL TEXTILE STITCHES D ARE CLOSED ON THE MALE ELEMENT B OF A MOLD A-B WHICH CONTAINS AN EXPANDABLE BLADE C; SPACE C, FORMED INSIDE BLADDER C, IS CONNECTED TO A PRESSURIZED FLUID SOURCE SO THAT THE FIXING OF THESE TEXTILE STAINS OF THE MALE ELEMENT, THE LATTER, WITH THE STYLES, IS INTRODUCED INTO FEMALE ELEMENT HAS MOLD AND A PRESSURIZED FLUID IS INTRODUCED IN SPACE C TO CREATE A CONTROLLED VOLTAGE OF THESE STOPS; BEFORE OR AFTER THE RESIN IS INTRODUCED INTO THE MOLD TO INCORPORATE AND FIX THE TEXTILE REINFORCEMENT OF THE TENSION, THE REINFORCING STRENGTH BEING PRESERVED IN THE HOLLOW ELEMENT OBTAINED.

Description

Method and device for producing resin hollow elements

  reinforced, in particular protective helmets,

and the elements thus obtained.

  The present invention relates to a method and a device for producing reinforced resin hollow elements, in particular protective helmets, and

the elements thus obtained.

  The uses of the reinforced resin hollow elements are well known, and in the particular case of protective helmets to which this invention applies in particular but not exclusively, these hollow elements must have a structure capable of withstanding shocks,

  even repeated, and must, moreover, be light.

  Efforts have been made to meet the conditions

  top by producing molded resin hollow elements

  reinforced with a suitable reinforcing textile.

  However, the structures of the hollow elements thus ob-

  only partially meet the desired conditions and do not satisfy other conditions

  important, in particular with regard to their

  repeated impact resistance In summary, the structure of these devices must be such that, under the effect of repeated shocks, even regularly located in the same area, the structure reacts elastically without the occurrence of cracks or scales that can damage it, thus ensuring a distribution of the shock over a larger area In the particular case of helmets, the formation of cracks and breaks along the meridian planes of the structure, should be avoided because

  it would be detrimental to the safety of the user.

  The subject of the invention is a hollow element, in particular in the form of a hairstyle, which can be used as an impact-resistant protective helmet in which a suitable textile reinforcement is incorporated in the binding resin so as to form a resilient structure whose resistance is as uniform as possible; A hollow element of the indicated type whose inner surface and the outer surface are smooth and can thus constitute the finished surface that it is easy to provide drawings and marks, even when the textile reinforcement or the elements constituting it are made from yarns or monofilament fibers, having a certain degree of rigidity, and tending to leave said surfaces; hollow elements whose outer surface hardly requires any finishing work and which, according to the end use, has the color and / or

  the desired design to meet aesthetic requirements.

c; and

  hollow resin elements having shaped shapes

  continuous and undercuts and such that parts of their surfaces form angles of less

  90 to a vertical plane.

  The method according to the invention in which the hollow element is provided with a reinforcement formed of several layers of woven fabric and / or threads incorporated in a bonding resin is characterized in that the textile reinforcing layers are applied on a two parts of a mold and in that at least a portion of the peripheral edges of said reinforcement is secured to said mold; a controlled tension is applied to the textile reinforcement and maintained during the next molding phase, in particular during solidification or polymerization of the binder resin; and the hollow member thus obtained is removed from the mold so that the textile reinforcement is incorporated and held in the resin in a stressed form. The woven fabric and / or net reinforcement according to the invention consists of several preformed elements in caps, at least a part of which is obtained by weaving the central zone of said cap under

shape of a spiral.

  Alternatively, the 3-elementary caps are obtained from a woven tubular element whose one end is in the form of a crown, the edges of the tips of said crown being united by stitching.

  or, in the case of materials having thermoplastic spun yarns

  welding, while the caps obtained are superimposed with an angular and successive offset of the union zones to form a homogeneous layer having

  a virtually uniform thickness.

  Depending on the use and the conditions that the hollow element has to fill, the weaving of the elementary caps can be done in such a way that we obtain

  areas of density or proximity of different meshes

  annuities which, during the molding of the element, are subjected to a controlled voltage produced by a fluid under

pressure.

  The prior application of the controlled tension to the textile reinforcement can be carried out according to appropriate criteria so as to correlate with the physical characteristics of the filaments or yarns forming the caps and / or the weaving characteristics of said caps. applied to textile reinforcement can be taken as a reference and considered as a limiting value of the mold of resilience or tensile strength

  filament or yarn used in each case.

  Of course, the tension previously applied to the textile reinforcement must correlate with the temperature of the molding and the treatment of the resins

  connecting elements used to obtain the hollow element

face.

  Also, with regard to the final use of the hollow elements obtained, the textile reinforcement may be associated with coating layers, on the inside.

  outside the intended hollow element, these

  may consist of film of resins

  suitable for example thermosetting resin films

  plastic, intended to be incorporated in the resin -4-

  binding or via thermoset resins.

  In the latter case, it is possible to obtain

  easily and quickly hollow elements, in particular

  bind helmets with a smooth outer surface and practically no finishing operations In addition, these coating films can be shaped in advance as external and / or internal caps to determine finished surfaces and characteristics. Thus, an outer cap made of a suitable material, for example a thermoplastic material, makes it possible to obtain smooth smooth surfaces and to prevent joints or projections formed by the textile reinforcing filaments from coming out of the surface of the sheet. In addition, the coating film or cap may be provided with drawings or figures that are reproduced on the surface of the element

  especially when the bonding resin of the

  Forcing textile is transparent, even in a limited way.

  The invention will now be described with reference to the accompanying drawings which illustrate by way of examples a preferred embodiment of the device for practicing the method of the invention. More particularly, FIG. 1 is a partial sectional view of the mold for setting in practice of the method of the invention; Figure 2 is a similar section of a variant of the mold; and FIGS. 3 and 4 show, on an enlarged scale and in a conventional manner, fragmentary sections of two

  hollow elements obtained according to the invention.

  The method according to the invention will now be described with reference to FIGS. 1 and 2 and relative to the

  manufacture of a protective helmet.

  To obtain this helmet, it is first necessary to prepare the textile reinforcement formed by two or more superposed woven layers having yarns.

  suitable for synthetic materials (thermoplastic resins

  and / or natural, vegetable (such as flax, cotton or the like) or mineral (such as asbestos, glass, etc.). Advantageously, textiles are used in the form of fabrics and / or fillets prepared at least in part with yarns or filaments of thermoplastic resins such as resins of vinyl, polystyrene, acrylic, polyamide, polyurethane, etc. type, in particular filaments

  of aramidic resins known as "KEVLAR".

  The textile reinforcement according to the invention consists of several superimposed layers which can vary by the composition of the yarns or filaments

  used and by the number of yarns in each layer.

  In addition, the density or the proximity of the stitches may also vary. Each layer of the textile reinforcement consists of a woven cap which is spirally wound to a given diameter, beyond which the weaving continues in a helix, although that the number of meshes of each turn of the cap in formation is maintained practically constant Otherwise, one obtains the cap from a tubular tissue of diameter

  To obtain elements of appropriate length

  one of the ends of each element is sewn in the form of a crown The tips of each crown are then folded inwards so as to place

  the peaks of the points on the axis of the tubular textile.

  Finally, the edges of the tips are joined together by seams or in the case of synthetic yarns also

  by welding so as to form the caps.

  A number of caps thus prepared (in practice at least two) are superimposed to form a

  textile reinforcement having the desired characteristics.

  When the bottom of the caps consists of welded tips during the superposition phase of the D-caps, meridian meridian ribs present an angular gap, one by ra-pport to the others, so as to

  what the paisselur and the structure of the textile reinforcement

  The tiles obtained are homogeneous and practically uniform.

  The edges DI caps 3 can be -iarige to -6- ensure their anchoring during the subsequent tension so that, during this operation, the various textile layers can slide freely on each

the others to stretch.

  Prior to the molding operation, the woven shells D thus prepared may be subjected to a preliminary treatment, for example imbibition by suitable materials, preforming and the like, in order to satisfy the particular requirements of the finished product.

obtained in each case.

  FIGS. 1 and 2 illustrate two forms of embodiment of the mold making it possible to practice the method according to the invention which, in this particular case,

  a protective helmet similar to that envisaged

  by the plaintiff in another patent.

  The illustrated mold consists of a female mold A

  and a male mold B with a molded element Bl for-

  said male mold which is subject to a superstructure plate

  port B 2 and housed as described in a shaped cavity A 1 of said female mold which reproduces the negative form

  The two parts A and B of the mold are subject to

  between them in known manner to the fixed and mobile planes

  a press that blocks them together as described above.

  after. According to the invention, the shaped element B1 retains an elastic coating C constituting a shaped bladder closed by a collar C 1 on the groove B 3 formed in the upper part of said shaped element. A closed space C is thus obtained between these elements. 2 connected by lines B 4 to a suitable source of pressurized fluid to expand and deform bladder C; preferably, oil or compressed air is introduced into the space C 2 under a pressure

appropriate, for example 20 bar.

  In FIG. 1, the periphery of the shaped cavity A 1 of the female mold A is provided with the shoulder A 2, the bottom of which is inclined and converges downwards. The shoulder -7- is closed by the plate B 2 of the mold male B to form a locking element of the textile reinforcement D

as described below.

  In the implementation of the method according to the invention, the superposed caps D forming the textile reinforcement are introduced into the cavity A 1 of the female mold A of FIG. 1. In the illustrated case, the textile reinforcement D is previously arranged between The hairdo

  F and the internal cap G whose characteristics

  The outer cap F which is close to the wall of cavity A, or which is in contact with it, is made of a suitable material, for example a textile fabric made from cotton yarns or the like to form an outer layer or a coating of appropriate consistency to prevent spikes or the like of the plastic caps D coming out of the helmet surface after molding The cap F may advantageously be made of a sheet or

  thermoplastic resin film, for example poly-

  ethylene, polyvinyl chloride or similar materials

  so that, from the subsequent molding stage, it is incorporated into the bonding resin and forms a smooth and well-finished outer surface having the

  Desired characteristics In particular it is possible to

  to produce helmets with the aesthetic characteristics

  ticks desired because the cap F can be colored on demand and wear drawings applied in advance, that

  it is made of textile materials or thermos

  In both cases, the cap F is subject to and incorporated in the bonding resin during the molding phase. Similar results are obtained with

  the internal cap G which, however, is also used

  as a protective element of the elastic bladder

C and other parts of the mold.

  As also shown in FIG. 1, after having placed the set of superimposed caps D, F and G in the female mold A, the enlarged edges D 1 of the textile caps D are folded outwards and lodged partially in the shoulder A 2 of said female mold whose depth is less than the thickness formed by said edges Di The outer cap F can be designed so that its edge F 1 is not located in the shoulder A 2 of the mold, so that during molding,

  this cap adheres to the molded cavity A 1 of the mold.

  To obtain a similar result, it is possible to use a cap F of appropriate size to adhere continuously to the cavity A 1 even when the edge of said cap is fixed on the bottom of the shoulder A 2, which

  always allows the appropriate tension to be

  forcing textile D during the molding phase.

  The male element B1 is then introduced into the

  reinforcement of the textile reinforcement D and the caps F and G previously housed in the cavity A 1; this operation is easy to perform because the elastic bladder C adheres to the shaped surface of said male element The coupling of the two parts A and B of the mold puts the plate B 2 in contact with the edges D of the caps D which are

  pressed and tightened on the bottom of the perimeter shoulder.

  pheric. A fluid under pressure, for example oil, at a pressure of 10 to 30 bar, which deforms the elastic bladder C, is then introduced into space G 1.

  textile reinforcement D This operation is carried out

  suitably to gradually exert pressure on the different textile layers of the caps D so that they completely conform to the shape of the walls of the cavity A 1 In particular, the importance of the pressure in the space C 2 is also determined by

  the textile structure used for the various

  fes D and the different zones of said headdresses

  Textile reinforcement D, as shown in Figs 3 and 4.

  In particular, the importance of the pressure, and consequently of the tension applied to the helmet D-caps, is correlated with

  the physical characteristics of the yarn forming the said

  textile forcing and with the uses and conditions that must be satisfied by the hollow elements obtained in each case In the particular case of helmets, a high resistance to shocks is necessary to avoid training

  cracks or delamination of the layers forming the structure

helmet.

  In general, we create the reinforcement tension

  textile D so that it does not exceed the resistance

  tensile strength of reinforcement D and, in particular in the case of helmets, the resilience modulus of the textile reinforcement yarn must not

to be surpassed.

  Obviously, and as illustrated by FIGS. 3 and 4, the tension applied to the textile reinforcement D

  may vary from one area to another of this reinforcement.

  In this case, the elastic bladder C has zones

  different elasticity, for example of different thicknesses

  to give more or less important

  In the zone of the textile reinforcement envisaged when the hollow element has protruding or shaped parts, the mold B can use the teachings of another patent of the applicant to reproduce the profiles.

desired in said element.

  After energizing reinforcement D, gold introduces a suitable resin into cavity A,

  molded by a pipe B 4 located in a suitable position

  required from the male mold B, for example a thermosetting bonding resin of the epoxy or polyester type. The bonding resin can be introduced beforehand into the cavity A 1 of the mold after having inserted the cap F into this cavity, in particular when the cap Y is made. a synthetic thermoplastic material for fcmer

  the outer surface of the hollow element

  its injected into the ca-litu A imbibe the textile reinforcement D and when the assembly is subjected to pressure by the elastic bladder C, it takes the form of said cavity A When the bonding resin is polymerized and solidified, the bladder C is relaxed, the mold is opened and the helmet is separated from the female mold A; the textile reinforcement D of the helmet is incorporated and fixed in the bonding resin and is maintained under a state of constant tension The external surface

  of the hollow element thus obtained is smooth and does not

  practically no finishing and also as

  this surface is colored at the request as above.

  indicated, the outer cap F can be colored

  and / or provided with drawings or the like.

  The hollow element, in particular the helmet, obtained is complete in all respects because its outer surface does not have projections or sharp points, even when the textile forming the reinforcement D consists of yarns or filaments having a flexibility

  limited as is the case of synthetic resins.

  What has just been described with respect to the mold of FIG. 1 applies to the mold of FIG. 2 with regard to the practice of the method. In this case, the enlarged edges D 1 of the reinforced D-caps are housed in the peripheral groove B 3 of the shaped element B 1 which also contains the fixing collar C 1

  fixing the caps D to the male part B of the mold

  cilite the production of the hollow element because the assembly formed by the caps D and F-G can be anchored on demand to said male element and the entire assembly always easily engages in the cavity A.

  We therefore see that we reach the goal of

  vention, that is to say that one obtains hollow elements resistant to mechanical forces, in particular the forces caused by shocks, the walls of these elements having a reaction resilient to said efforts due to the presence of the textile reinforcement

which is under permanent stress.

  It is possible for the operation of tensioning the textile reinforcement D to deform the woven fabric or the network in a direction substantially parallel to the radial or substantially radial planes of the hollow element obtained. can be applied to the layers constituting the textile reinforcement D so that from the internal layers the tension varies gradually towards the outer layers, for example by modifying the proximity of the stitches and / or the title of the yarn forming the different caps

  reinforcement as well as the dimensions of the caps.

  It is obvious that one can apply the same criterion when one wishes to apply a tension practically

  consistent and consistent with the different layers of

  Other variants and modifications of the process of the invention or of the mold used can be carried out according to the properties which the hollow elements obtained by this process must exhibit without departing for that purpose.

framework of the invention.

12 -

Claims (13)

  Process for obtaining hollow elements made of reinforced resin, in particular protective helmets, said reinforcement consisting of several layers of woven fabric and / or mesh embedded in a binding resin, characterized in that the layers of textile reinforcement (D) on one of the two parts of a   mold (A-B) and at least a portion of the circumferential edges are   phériques (D 1) of said reinforcement to said mold; a controlled tension is applied to said textile reinforcement and   during the next molding phase, in particular   bind during polymerization and solidification, and   demold the hollow element obtained so that the   textile forcing of said element is incorporated and retained   by the resin in a constrained form.   Process according to Claim 1, characterized in   what is applied to the layers constituting the   textile fabric (D) a tension which varies from the inner layers to the outer layers of said textile reinforcement   and maintaining said voltage during the molding phase.   Process according to Claim 1, characterized in   what is applied to the layers forming the textile reinforcement   the (DI a virtually constant tension and one keeps said tension during molding.   4. Method according to one of claims 1 or 2,   characterized by preforming the textile reinforcement (D), for example in the form of a cap, and fixing at least a portion of the edges (D 1) of the elementary cap to one of the parts (AB) of the mold and their hold during   energizing said reinforcement.   Process according to any one of the claims   1 to 4, characterized in that the tension   to the layers of textile reinforcement (D) by means of a bladder (C) which can be elastically deformed   by a fluid under pressure, preferably a liquid.   Process according to any one of the claims   at a 5, characterized in that the textile reinforcement 13 (D) is subjected to a tension which is lower than the modulus of resilience of the filament or yarn used to produce the textile said reinforcement.   7. Process according to any one of the claims   1 to 6, characterized in that the textile reinforcement consists of several woven textile caps (D) whose edges (D 1) are at least partially enlarged to form an anchor during energizing of the caps.   Process according to any one of the claims   1 to 7, characterized in that between the textile reinforcement (D) and the mold walls (AB) is interposed at least one layer or film (FG) which forms at least a part of the outer surface and / or internal of the hollow element.   9. Method according to claim 8, characterized in that reproduced beforehand on the film (F) colors and / or drawings which are transformed   during molding on the surface of the molded hollow element.   Process according to one of claims 8 or 9,   characterized in that one uses as a perimeter film   phérique (F-G) a film of thermoplastic material which is incorporated and fixed to the structure of the element   hollow during the molding operation.   Process according to any one of the claims   1 to 10, characterized in that fibers or fibers of natural and / or synthetic materials which, at least partially, are thermoplastic, are used as textile reinforcement materials (D) for incorporation into the fabric. resin of iaison during molding.   12. Mold for the practice of the method according to any one of the revendicatlons 1 i 1 whose female part reproduces in regatif the form ri 1 i hollow indent to obtain, characterized by a device for fixing at least a portion of the edges ( D) of the textile reinforcement (D) while at least part of the walls (C) of 14 - the male element (B) of said mold is made of an elastically deformable material and creates voids (C 2) for a fluid under pressure which deforms said walls for   to give controlled tension to said textile reinforcement   the (D). Mold according to claim 12, characterized   in that its male element (B) has, towards one of its ex-   trenches, a circumferential groove (B 3) which holds the edges (D 1) of the textile reinforcing caps and the edge of an elastically deformable bladder (C)   which puts said caps under tension.   14. Mold according to claim 12, characterized by a peripheral shoulder (A <) and a corresponding projecting portion (B 2) disposed between the edge of the opening of the cavity (A 1) of the female element (A). and the plate of the male member (B) for firmly holding together at least a portion of the edges (D 1) of the caps (D) of the textile reinforcement, while said male member (B) has at least one elastic bladder   (C) to turn on said caps.   15. Hollow element made of reinforced resin, in particular protective helmet, obtained according to   method of any one of claims 1 to 10,   characterized in that its reinforcement (D) in the form of a woven fabric or a net is incorporated under   stress in the bonding resin of said reinforcement.   Hollow element according to claim 15, characterized in that its outer and / or inner layer surface (FG) held firmly in the structure of said element is capable of preventing spikes or the like formed by the filaments or spun. textile reinforcement out of said surfaces. Hollow element according to claim 16, characterized in that its outer surface layer (F) consists of at least one sheet of thermoplastic material which can be incorporated in the   binding resin of said hollow member. -   Hollow element according to one of the claims   16 or 17, characterized in that the outer surface (F) is provided with the desired patterns and / or colors which   are almost reproduced as a result of the trans-   the surface of the element itself.