CH650445A5 - PROCEDURE FOR MAKING CABLES BODIES IN ARMED SYNTHETIC RESIN, IN PARTICULAR PROTECTIVE HELMETS. - Google Patents

Description

The present invention relates to a process and the relative mold, for making hollow bodies, in reinforced synthetic resin such as, for example, helmets.

The requirements intended to satisfy the intended use of hollow body in reinforced resin are known and in the specific case of protective helmets - where the invention finds particular but not exclusive application - these bodies must have a structure resistant to impact, even repeated; inol-55 three must be light.

An attempt was made to meet these needs by making hollow bodies in molded resins reinforced with a suitable textile reinforcement. The structures of the hollow bodies thus obtained, however, only partially satisfy the required requirements and leave other important requirements unfulfilled, especially with regard to their resistance to repeated impacts. In short, it is required that these bodies present a structure such that under the action of repeated impacts even if always located in the same area, it reacts elastically, without producing cracks or flaking which can affect the structure concerned, guaranteeing on the other hand, that the impact action is distributed over a large area. In particular in the case of helmets, the formation of inertia must be avoided.

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nature and long breaks of the meridian planes of the structure and which compromise the safety of the user.

The present invention has the task of making impact-resistant protective helmets in which a suitable textile armor is embedded in the bonding resin.

Another object of the invention is to provide hollow bodies whose external surface does not practically require finishing operations and which, in relation to the needs of use, presents desired colors and / or designs and this to satisfy aesthetic requirements.

The process according to the invention, in which the hollow body in synthetic resin involves an armature consisting of a plurality of layers woven in a mesh and / or mesh, incorporated in a binding resin, is characterized in preparing the layers of the textile armor on one of the two parts of a mold and in anchoring at least part of the peripheral edges of said reinforcement to said mold; applying a controlled tension to said anchored textile reinforcement and maintaining it during the subsequent molding phase and during the polymerization of the binding resin; removing the hollow body obtained from the mold, so that this textile reinforcement is incorporated and held in the resin in a state of tension.

In relation to the intended use and the needs required of the hollow body made, the weaving of the elementary caps can be carried out in such a way as to present areas of different density or density of weaving to which areas during the molding of the body are applied a controlled voltage produced by a fluid under pressure.

The prior application of the controlled tension to the textile reinforcement can be done with appropriate criteria and such as to take into account the physical characteristics of the threads or yarns constituting the caps and / or the weaving characteristics of said caps. For example, the tension applied to the textile weave can refer and consider as limit value the modulus of elasticity or the breaking load of the thread or yarn used from time to time. Obviously this tension applied beforehand to the textile reinforcement also takes into account the molding or treatment temperatures of the binding resins used to make the hollow body considered.

Again in relation to the intended uses of the hollow bodies obtained, the textile reinforcement can be associated with internal and / or external coating layers to the considered hollow body, which layers may consist of films in suitable resins, for example thermoplastic to be incorporated into the binding resin or from thermosetting resins. In the latter case, it is possible to easily and quickly make hollow bodies, in particular helmets, whose external surface is smooth and requires practically no finishing operations. Furthermore, the said covering films can be previously molded to external and / or internal caps to determine the finished surfaces and the desired characteristics of the said bodies. Thus, for example, an external cap made of suitable material, for example thermoplastic, allows to obtain smooth and smooth surfaces, and prevents points or projections formed by the threads of the textile armor from protruding from the surfaces of the hollow body. Furthermore, the coating film or the cap may present drawings or figures in general which are thus reproduced by the surface of the hollow body especially when the binding resin of the textile reinforcement is transparent even to a limited extent.

The invention will now be explained by the following description which refers to the annexed drawings which illustrate, by way of example, a preferred embodiment of the device which carries out the process according to the invention. Precisely:

fig. 1 'is the partial schematic section of the mold which carries out the process according to the invention;

5 fig. 2 is an analogous section of a variant embodiment of the mold;

fig. 3 and 4 show, on an enlarged scale and in conventional form, fragmentary sections of two hollow bodies, made according to the invention.

The method according to the invention will now be explained in relation to figs. 1 and 2 of the attached drawings and the realization of a protective helmet.

To make the helmet in question, first the textile reinforcement is prepared, made up of two or more superimposed layers of knitted fabrics with appropriate yarns in synthetic (thermoplastic resins) and / or natural materials; vegetables (such as flax, cotton and the like) or minerals (such as asbestos glass and so on). Advantageously, knitted and / or net fabrics prepared at least in part with threads or filaments of 20 thermoplastic resins such as vinyl, polystyrene, acrylic, polyamide, polyurethane and so on are used, in particular aramid resin filaments called «KELAR» are used.

According to the invention, the textile weave is made up of a plurality of overlapping woven layers, which can vary, both as regards the composition of the threads or filaments used, and also as the number of threads of each woven layer. Furthermore, the density or density of the texture may vary. Each layer of the textile reinforcement consists of a knitted cap or cap knitted with a spiral pattern up to a certain diameter, after which the knitted weave continues with a helical pattern, i.e. the number of stitches, for each turn of the cap in formation is kept practically constant. Or, the cap is made starting from a tubular knitted fabric of the necessary diameter, obtaining elements of the desired length, one of the ends of each of which is shaped in points to form a crown with cusps. The cusps or segments of each crown are then folded inwards to arrange the 40 tips of the cupsids in correspondence with the axis of the tubular fabric. Finally, the edges or edges of the cups of the cups are joined together, by stitching or, in the case of synthetic threads, also by welding, to thus create the caps.

45 A certain number of caps thus prepared (in practice this number can vary from two to more) are superimposed to thus create the textile reinforcement of the desired characteristics. When the bottom of these caps is made up of cusps or segments welded during the overlap of the caps D the meridian joining ribs are moved angularly to each other, so that the thickness and structure of the textile reinforcement obtained are homogeneous in structure and practically constant and uniform thickness. The edges Dj of the caps D can be enlarged 55 to ensure their anchoring during the subsequent tensioning in order to ensure that, during this operation, the different layers of fabric can freely flow between them and tension.

The D-knitted caps thus prepared and prior to the molding operation can undergo preventive treatments; for example imbibition with suitable materials, pre-shaping and so on in order to satisfy the needs of use of the manufactured item from time to time. Always considering figs. 1 and 2 of the drawings, they illustrate two forms of embodiment of the mold, by means of which the process according to the invention is implemented which in the specific case produces a protective helmet and which is similar to that considered by another patent of the same author.

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The illustrated mold consists of a die A and a punch or male B comprising a shaped body Bj constituting the actual punch integral with a support plate B2 and which is housed in the way that will be said later in the shaped cavity Aw of said matrix and which reproduces, in negative, the shape of the helmet. The two parts A and B of the mold are constrained in a known way to the fixed and mobile planes of a press to tighten them together in relation to what will now be said.

According to the present invention, the punch Bi retains an elastic coating Ç constituting a shaped lung tightly sealed by a collar Cx to a groove B3 provided towards the upper part of said punch. In this way, an interspace C2 sealed and connected, by means of conduits B4 with a source of fluid at a suitable pressure, will be created between these parts to dilate and deform the lung C; preferably oil or compressed air is introduced into the cavity C2 at a suitable pressure, for example at 20 atm. On the other hand, through the conduits B5, the fluid resin which incorporates these tensioned D caps is introduced into the cavity of the matrix A outside and / or inside the caps DI.

In fig. 1 the peripheral edge of the shaped cavity Al of the matrix A has a stop A2 whose bottom is inclined and converging downwards. This stop is closed by the plate B2 of the punch B to thus form a clamping member for the textile reinforcement D in relation to what will now be said.

Still in relation to the implementation of the method according to the invention in the cavity Ax of the matrix A of fig. 1 introduces the plurality of superimposed caps D constituting the textile reinforcement.

In the case shown, the textile reinforcement D is previously arranged between the caps: F external and G internal with characteristics suitable for the purposes to be achieved and which will be said. The outer cap F, which is close to or in contact with the wall of the cavity Aj, is made of suitable material, for example it is made of knitted fabric with cotton yarns and the like, to constitute an external or coating layer of suitable consistency which avoids that the tips or the like of the synthetic yarn caps D may protrude after molding from the surface of the helmet. The outer cap F can advantageously be made with a foil or film in thermoplastic resins such as polyethylene, PVC and the like so that during the subsequent molding phase, it is incorporated into the binding resin and forms a smooth and finished external surface with the volutes features. In particular, it is possible to make helmets with the desired aesthetic characteristics since the cap F can be colored in the desired way and present designs generally reproduced in advance on said caps F, whether they are woven or in thermoplastic materials. In both cases the cap F is anchored and incorporated in the binding resin during the molding operation.

Similar results are achieved by the inner cap G which, however, is also provided as a protective element for the elastic lung C and for other parts of the same mold.

Still with reference to fig. 1 of the drawing, after placing in the matrix A the group of caps DFG superimposed on each other, the enlarged edges Dt of the woven caps D are turned outwards and housed in part within the abutment A2 of said matrix whose depth is less than thickness formed by said edges Dt.

The outer cap F can be made so that its edge Fj is disengaged from the stop A2 of the mold so that during molding this cap is made to adhere to the shaped wall of the cavity Aj of the mold. A similar result can be achieved by providing the cap F suitably sized and such as to adhere continuously to the cavity Ai even when the edge of said cap is tightened on the bottom of the stop A2 always allowing that the textile reinforcement D can be given the due tension during the molding operation D.

The male Bj is then introduced into the opening of the textile mature arm D and of the caps F and G previously allocated in the cavity A1 and this operation is easily carried out since the elastic lung C adheres to the shaped surface of said male. The coupling of the two parts A and B of the mold engages the plate B2 with the i5 edges Dj of the caps D, which are thus pressed and tightened on the bottom of the peripheral stop.

Subsequently, a pressurized fluid, for example oil at a pressure of 10-30 atm, is introduced into the cavity C2 which, deforming the elastic lung C, puts the textile reinforcement D under tension.

This operation is carried out in an appropriate way and such as to gradually apply this pressure to the various textile layers of the caps D, to make them adhere completely to the shapes of the cavity walls. In particular, the extent of the pressure within the cavity C2 is determined also taking into account the textile structure provided, both from the different caps D and also from the different areas of each of said caps of the textile armor D and this as illustrated in figs. 3 and 4.

30 In particular, the amount of pressure and therefore of the tension applied to the caps D of the textile reinforcement of the helmet takes into account the physical characteristics of the threads constituting this textile reinforcement, and the purposes and needs of use required by the hollow bodies of time to time made. 35 In the specific case of helmets, the latter requires high impact resistance, without flaking or delamination of the layers making up the structure of the helmet.

Generally, the tensioning of the textile armor D, 40 is carried out so as not to exceed the breaking load of the yarn constituting the armor D and particularly in the case of helmets, the elasticity modulus of the yarn of the yarn must not be exceeded. textile armor.

Obviously and with reference to figs. 3 and 4 of the drawing, the tension applied to the textile weave D can vary from area to area of said weave. In this case, the elastic lung C is provided with areas of different elasticity, for example of different thickness, so as to stretch more or less strongly the considered area of said reinforcement. If I know that the hollow body has protruding or shaped parts, the male B can use the teachings considered by the other patent of the same author to reproduce the due profiles in said body.

After tensioning of the armature D, a fluid resin suitable for example a thermosetting resin constituting the binding resin of the epoxy or polyester type is introduced into the mold cavity 55 Aj in a suitable position of the male B. The binding resin can be previously introduced 60 into the cavity A1 of the mold, after having placed the cap F in said cavity particularly when the latter is made of synthetic thermoplastic material to constitute the external surface of the hollow body made. The binding resin introduced into the cavity A1 imbues the textile reinforcement D 65 and when the whole is put under pressure by the intervention of the elastic lung C, it takes the form of the said cavity Aj.

When the binding resin has cured and solid-

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hardened, the pressure is released from the lung C, the mold is opened and the helmet whose textile armor D is embedded and anchored to the binding resin and is kept in a state of constant tension is removed from the matrix A. The external surface of the hollow body obtained is smooth and smooth and practically does not require finishing, also because this surface is colored as required by the use of the hollow body since, as already mentioned, the outer cap F can be colored and / or present drawings or other.

The hollow body and in particular the helmet obtained is complete in all respects, since its external surface is smooth and faithfully reproducing the shape presented by the cavity A1 of the die. Furthermore, this external surface has no points or protrusions even when, as in the case of the threads which can protrude from the fabric constituting the textile reinforcement D.

After what has been said about the mold of fig. 1, the same considerations apply to the mold of fig. 2 also as regards the implementation of the procedure. In this case the enlarged edges Dj of the reinforcement caps D are placed in the peripheral groove B3 of the punch Bj which also retains the clamping collar Cv II fixing the caps D to the punch B of the mold facilitates the realization of the hollow body as the assembly formed by the caps D and FG it can be anchored as required to the said punch and the whole is always easily engaged in the cavity A.

After the above, the pre-5 fixed purposes of the present invention are confirmed, namely to provide hollow bodies resistant to mechanical stresses in particular those of impact, so that the walls of these bodies react elastically to these stresses given the presence of a textile armor in a state of permanent compulsion.

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In relation to the operation of tensioning the textile reinforcement D this operation can be carried out in such a way as to deform the knitted or net fabric in a direction substantially parallel to the radial or substantially radial planes of the hollow body made. This tension can be applied to the layers making up the textile armor D so that starting from the inner layers it gradually changes towards the outer layers, for example by varying the thickness of the weaving of the knit and / or count of the yarns constituting the different caps of said armor, as well as the dimensions of these caps. Obviously, a similar criterion can be provided in the case that it is desired to impart a substantially uniform and constant tension to the different layers of the textile reinforcement D.

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1 sheet of drawings

Claims (17)

650445 1. Procedure for making hollow bodies in reinforced synthetic resin, in particular protective helmets, the reinforcement of which is made up of a plurality of layers woven in mesh and / or mesh, embedded in a binding resin, characterized in preparing the reinforcement layers textile (D) on one of the two parts of a mold (AB) and in anchoring at least part of the peripheral edges (DJ of said reinforcement to said mold; in applying a controlled tension to said anchored textile reinforcement and in maintaining it during the subsequent molding phase and during the polymerization of the binding resin and in removing the hollow body, obtained from the mold, so that the textile reinforcement of said hollow body is incorporated and held in the resin, in a state of tension. 2. Process according to claim 1, characterized in applying to the layers constituting the textile reinforcement (D) a tension which varies from the internal layers towards the external layers of said textile reinforcement and in maintaining these tensions during the molding. 2 3. Process according to claim 1, characterized in applying a substantially constant tension to the layers constituting the textile reinforcement (D) and in maintaining this tension during molding. Method according to claims 1 and 2, characterized in preshaping the textile reinforcement (D) for example with a cap and anchoring at least part of the edges (DJ of the elementary caps to one of the parts (AB) of the mold and holding them there during the tensioning of this armature. 5. Process according to claims 1 to 4, characterized in applying the controlled tension to the layers of the textile coating (D) by means of a wall (C) elastically deformable by a fluid under pressure, preferably a liquid. Method according to claims 1 to 5, characterized in applying to the textile weave (D) a tension lower than the modulus of elasticity of the thread or yarn used to make the fabric of this weave. Method according to claims 1 to 6, characterized in that the textile weave is constituted by a plurality of knitted caps (D), the edges of which (DJ are at least partially enlarged, to constitute an anchorage during the tensioning of the caps incorporated in the resin in a state of tension. Process according to claims 1 to 7, characterized by interposing at least one layer (FG) between the textile reinforcement (D) and the walls of the mold (AB) which forms at least part of the external and / or internal surface of the hollow body . Method according to claims 1 to 8, characterized by interposing between the textile reinforcement (D) and the internal wall of the mold (A) a film (F) on which drawings or colors have previously been reproduced so that the latter, during molding, are shown on the molded hollow body. Method according to claims 1 to 9, characterized in using as an external layer of the hollow body the thermoplastic film (F) which during molding is incorporated and held firmly in the structure of the hollow body. 11. Process according to claims 1 to 10, characterized in the use, as material for the textile reinforcement (D) of knitted or net fabrics composed of yarns and fibers of natural and / or synthetic materials, at least in part of which the latter are thermoplastics to be incorporated into the ligament resin during molding. 12. Mold for carrying out the process according to claims 1 to 11, the matrix of which has a negative impression of the hollow body to be made, characterized by means for retaining at least part of the edges anchored (DJ of the textile armor (D), while at least part of the walls s (C) of the punch (B) of said mold are made of elastically deformable material and have cavities (C2) to establish the pressure of a fluid which deforming these walls imparts the controlled tension to said textile reinforcement (D ). I Mold according to claim 12, characterized in that the punch (B) has towards one of its ends a peripheral groove (BJ within which both the edges (DJ of the caps of the textile weaves, and also the edge of an elastically deformable lung (C) which puts said cuplets under tension. Mold according to claim 12, characterized by a stop (AJ presented by the die and by a relative projection (B2) entailed near the edge of the opening presented by the cavity (AJ of the die (A) and in which 20 engages the plate of the punch (B) in order to keep at least part of the edges (DJ of the caps (D) of the textile weaves tightened, while the said punch (B) also holds the edge of the elastic lung (C) which puts the said tension under tension caps. 25 15. Hollow body in reinforced synthetic resin, carried out with the process according to claims 1 and 10, characterized in that its external and / or internal surface is constituted by a layer (FG) held in firm union with the synthetic resin structure incorporating the woven layers of said body so that the tips of the ends of the threads protruding from the hollow body, formed by synthetic resin threads, are crushed and made to re-enter the surface of the hollow body by means of a foil of flexible material applied to said hollow body to crush and avoiding the projection 35 of said points. 16. Hollow body according to claim 15, characterized in that its external surface layer (F) is constituted by at least one sheet of thermoplastic material incorporated in the binding resin of said hollow body. 40 17. Hollow body according to claims 15 and 16, characterized in that the outer surface layer (F) has drawings and / or colors shown on said layer integral with the structure of the hollow body.