NO822066L - METHOD AND APPARATUS FOR MANUFACTURING HOLE BODIES OF ARMED RESIN - Google Patents

Description

I i - : i . The present invention relates to a method and tjil-! corresponding device for the production of hollow bodies in reinforced resin such as helmets etc.

i I The application requirements for reinforced resin hollow bodies

is well-known and in the special case when it comes to protective helmets, such as the present invention is special! must additionally have a light weight.

ill

II'

In Man has tried to satisfy the aforementioned requirements by adding

1 'ii way to introduce hollow bodies in cast resin which is reinforced!

with a suitable textile reinforcement. The structure, for the bodies thus obtained, however, only partially satisfies the I I 'desired requirements and does not satisfy other important requirements,! j in particular with regard to resistance to repeated shocks.

'i 1 The structure of such devices must be such that in the event of shocks, even if they are constantly located in the same area, the structure will behave elastically without the formation of cracks or peeling which could destroy the structure and : thereby causing that a shock is distributed over a larger area.' For the case helmets rna especially the formation of cracks and i i 'br1 udd along the meridian planes of the structure is then avoided like this! iIi : cracking or breaking may cause danger to the user. in I I . The present invention provides hollow bodies, specially shaped as headgear and which are capable of being used as shock and impact protective helmets and in which a suitable textile reinforcement is baked into a binder resin in such a way that an elastic structure is formed if resistance is as evenly distributed as possible.

in i

A further purpose of the invention is to provide a hollow body of the specified type, whose internal and external surfaces are smooth and can thus constitute the finished veri-surface which can easily be provided with signs or markings and when the textile reinforcement or the elements that make up these | 1 ! i i is yarn.or single-filament fibers have a certain degree of stiffness

|.pg which nar a tends to stick out from the surface. j

!■ '''■' ii

A further object of the invention is to provide hollow bodies whose external surface practically does not require n! oe finishing work and which, in accordance with the need for use, is provided with the desired color and/or markings to satisfy an aesthetic requirement.

A further purpose of the invention is to provide hollow bodies in resin with discontinuous shape and grooves. \ the underside and which are such that parts of their surfaces form angles of less than 90° in relation to a vertical plane.

•.in

! i i ! ■ 1 The method according to the invention which provides, In the hollow body is provided with a reinforcement formed by a j number of woven textiles and/or mesh layers incorporated !i 1 ' ! i j a binding resin and is characterized by the fact that textile;- !

the reinforcement layers are applied to one of the two parts of the mold and 1 that at least part of the peripheral points of the reinforcement in '■

i i is attached to the mold using a controlled i

IN

tensile stress in the textile reinforcement and maintaining this during the subsequent casting phase and especially during the solidification or polymerization of the resin, after which the thus hollow body is removed from the mold so that the textile reinforcement is incorporated here and held in the resin under ■a stretched state..

/ The woven and/or mesh textile reinforcement according to the invention consists of a number of elements which are pre-shaped in the shape of a cap, at least a part of which is obtained by weaving the central zone of the cap in the form of a spiral. Alternatively, single caps can be obtained from a woven tubular body, one end of which is shaped like a crown, where \ the edges of the flaps in the crown are attached by stitching or in a case where the material contains thermoplastic yarn by means of welding and where such obtained caps are placed on in each other with an angular displacement so that on each other j the following united or attached areas form homogeneous layers 'méd practically a thickness... !

V i..; ■ s i I Depending on the end use for the hollow body, the weaving of the individual caps can be carried out in such a way that it is provided ! areas with varying density or tissue density which during the casting of the body are subjected to a controlled stretch;-

! i In tension, formed by a liquid under pressure.

<!>'

1 The controlled tensile stress as the textile reinforcement | certain properties can be given in advance in order to correlate these with the physical properties of the threads in the yarn that form the caps and/or the weaving properties of the caps. E.g. the applied tensile stress to which the textile in the reinforcement is exposed can be referred to as and considered as a limit value determined by the yarn's modulus of elasticity or in the tensile strength of the yarn or thread in each case. Obviously, the added stress to the textile reinforcement must be correlated with the casting temperature and the influence of the binder resins used to obtain the hollow bodies

... - i i 1 Again with regard to the intended end use for the j 'obtained hollow bodies, the textile reinforcement can be combined j with lining layers on the inside and/or on the outside of the hollow j body, which layers can consist of suitable resin films, j

" ■ ■ ■ i ! i for example thermoplastic resin films which are incorporated! i j

■the binding resin or in the thermosetting resins. In the latter case, it is possible to quickly produce hollow bodies, especially helmets whose outer surface is smooth and does not require any finishing work. Additional kanj I such liner films are preformed in the same manner as the|j !external and/or internal caps to determine the finish<1>I

i ■ ■ I

1 of the surfaces and the desired properties for the bodies. I j For example, the outer hood can be made of a suitable material, e.g. in a thermoplastic, such make it possible to obtain smooth, even surfaces and avoid joints or protrusions formed by the textile reinforcement threads which may protrude from the surface of the hollow body. Furthermore, the lining film orj i<i>j

the cap must be provided with signs or figures that may be rel-

''I''

;produced on the surface of the hollow body, especially when; the 'binding resin in the textile reinforcement is transparent^ ■ •

i i i sj elv a limited degree.i! ' iI

The invention shall be explained with reference to the attached drawings which show a preferred embodiment of the device for carrying out the present method.

IN

ill.

in FIG. 1 schematically shows a cross-section of the mold with which the present method is used,

FIG. 2 shows a corresponding cross-section of a variant of

In the form, and in :FIG. 3 and 4 show on an enlarged scale and in conventional I

in the form of partial cross-sections of two hollow bodies obtained in

in keeping with the discovery.

i The present procedure must be explained under reference.

in ; ■ in !to fig. 1 and 2 and for the construction of a protective ! helmet.. I .

in 1 ! To produce the helmet in question, it is necessary first

in producing the textile reinforcement formed by two or more j 'overlapping, woven layers of. suitable synthetic yarns or: synthetic materials (thermoplastic resins) and/or

■natural materials such as vegetable (such as linen, cotton etc.) or mineral (such as asbestos, glass, etc.). , ;

Advantageously, woven and/or mesh textiles are used I '!made at least partially from threads or filaments<1>;

of thermoplastic resins such as polyvinyl, polystyrene, j ,polyacryls, polyamide, polyurethane resins.e.1.'and more

1 in particular filaments of "aramidic" resins known under I

l the trade name "KEVLAR". j

The textile reinforcement according to the invention is formed by

.a number of overlapping layers, which can vary both in

with regard to the composition of the threads or filaments j used as well as the number of threads in each layer. Furthermore, the weave density can also be varied. Each layer of i in the textile reinforcement consists of a woven cap wound in 1 s: spiral up to a given diameter, beyond which..vi eveni

continues spirally, i.e. that the number of stitches for each '. rotation of the cap that is formed is kept practically constant. i 1 Alternatively, the cap can be obtained by starting from - a tubular form of I ■ woven textile of equal diameter. To obtain elements of the desired length, one of the ends will be sewn in the form of a crown, j ! The flips or points are bent inwards to bring the peaks 1 ! in a' v f- the lips to the axis of the tubular textile. Then the edges or border lines of each flap are united with 1 I h1 each other by sewing together or in the case of synthetic I ! t' also prevails when welding to thus form the caps. j in JI

; A certain number of hoods produced in this way (in practice the number can vary from at least two and upwards) are placed on top of each other

■ to provide a textile reinforcement with desired properties.

' When the bottom of the caps consists of f lips welded together ij

'the overlapping phase of the caps D will the meridian which unites j

the ribs be angularly offset in relation to each other in such a way that the thickness of the structure for the resulting textile reinforcement is homogeneous and practically uniform. The edges pl .; of the caps D can be enlarged to ensure anchoring ! ; during the subsequent stretch so that during this opera-! tion, the different .textile layers can freely slide over each other : and be brought under tensile stress. The thus produced caps in D can be subjected to a preliminary treatment before the molding operation, • for example impregnation with suitable materials, preformnirigJ ! etc. to satisfy special requirements in the finished product, j

■ product in each individual case.<1>

' i<1>

With reference to figures 1 and 2 in the drawings, j j shows these, two embodiments of the form by means of which the present method can be practiced and as in the present;

case provides a protective helmet. The shown' in : form consists of a female part A and a male part B provided with a shaped body Bl which constitutes the male part and which is attached to

a carrier plate B2 and placed as described in the cavity Al in the female part which reproduces as a negative the shape of the helmet.i

' The two parts A and B of the mold are attached to each other in a known manner

, i

i. way to two fixed and movable planes of a press to ;

'attach them to each other according to the following.:

f -i I According to the invention, the shaped body Bl holds the elastic lining consisting of a shaped bladder (bladd) closed

I using a collar Cl to the track. B3 arranged in- the upper ! in 1 ! 1 In part of the shaped body. A sealed gap C2 is thus obtained between these i ' d' or a sealed gap C2 which by means of i? o the conductor B4 is connected to a suitable pressure source medium to expand and expand the bladder C, preferably oil or compressed air is introduced into the gap C2 at a suitable pressure, for example at 20 atm.

in

In fig. 1 is the peripheral edge of the shaped cavity Al : of , the female body A is provided with a shoulder A2 whose biinndel is|<1>

<1>oblique and converging downwards. The shoulder is closed by a j

■ plate B2 in the male part B to form a blocking element |

; for the textile reinforcement D, as indicated below.

, I i ; Again according to the present procedure, ji J is introduced

: the cavity in the female part A in fig. 1 a number on each otherj j

i i horizontal hoods D which make up the textile reinforcement. In the case shown j is the textile reinforcement. D arranged between ! in an outer cap F and an inner cap G exhibiting properties .; In suitable for the desired purpose that will be described in it; ,

subsequently.

: i

IN

The outer hood F which is close to or in contact with the wall

: in the cavity Al is made of a suitable material, for example a textile woven from cotton or equivalent yarn to provide an external layer or coating of a suitable composition which is

capable of preventing points etc. of the hood D of j synthetic material protrudes from the helmet surface after! casting. The cap F can advantageously consist of a laminate or: a film of thermoplastic resin, for example polyethylene, in PVC or similar materials so that during the subsequent molding phase it is incorporated into the resin binder to give a smooth outer surface with a nice finish with the desired properties. jD! it is particularly possible to produce helmets with the desired aesthetic properties as the hood can be colored and provided with

with pre-applied markings, whether the caps are made of textile or thermoplastic materials. - In both cases the cap is F !

! ■ 'i ; attached to and incorporated into the binding resin during the casting phase. Similar results are achieved with the inner; in hood G which, however, is also provided as a protective 1; e■ i element for the elastic bladder C and ? for other parts of i<il>I

j the mold. II

I' again with reference to fig. 1 it will be after introduction ■ 1j

of the overlapping caps D, F and G in the female part' A

. the enlarged edges Dl of the textile caps D folded outwards and partially placed inside the shoulder A2 of the female part, whose;.-:: depth is less than the thickness constituted by the edges Dl. Il

It. vtre hood F can be arranged in such a way that its

in

■ edges Fl are released from the shoulder A2 of the mold, adhere to the shaped cavity Al of the mold. Similar results can be obtained by providing the cap F which is suitably sized and is arranged so that it adheres continuously to the cavity Al, even when the edges of the cap are attached to the bottom of the shoulder A2 and thus enables an appropriate tensile stress to be always provided in the textile reinforcement D during the casting phase. ,

The male element Bl is then introduced into: the opening of the textile reinforcement D and the caps F and G previously placed in the cavity Al, this operation is easily performed because it ij

elastic bladder C is attached to the shaped surface of

in

i in the male element. Connecting the two parts A and B of the ] j mold brings the plate B2 into engagement with the edges D1 of the caps

D which is thus pressed firmly at the base of the peripheral shoulder.

Then a pressure fluid will be introduced into the gap C2, for example • oil at a pressure of 10 - 30 atm., which deforms the elastic1 ' bladder C and thus affects a tensile stress on the textile reinforcement D. This operation is carried out in a suitable way ' so that the pressure gradually affects the different textile layers I of the sheaths D and brings them into complete agreement with the shape of the walls of the cavity Al. More specifically will

: the pressure in the gap C2 is determined based on the used textile'*-i • structure, also with regard to the different caps C o: g those in different zones for each of the caps of text for the reinforcements D as shown in fig. 3 and'4. j j

i ' ' j-More particularly, the size of the pressure and consequently the tensile j j stress that is placed over the caps Di the helmet's textile fpr- j ' < strengthening will be correlated with the physical properties of j. the threads that make up the textile reinforcement and the purpose and I the requirements for the end use for the hollow bodies that are

.held in'every case.. Especially for helmets where a high j

■; s.shock resistance is necessary to avoid the formation of J j cracks or delamination of the layers that make up the helmet. in in structure. |

ii In general, the tensile stress in the reinforcement D will provide-<1>: be brought in such a way that it does not exceed the tensile strength of the yarn making up the reinforcement D and especially for helmets

i the elasticity module for the yarn in the textile reinforcement 1 must not be exceeded. j j 'Obviously with reference to.fig. 3 and 4 can the voltage which

if the textile reinforcement D is applied, it varies from zone to zone.

, 1 the gain. In this case, the elastic will blister;

C be provided with zones of varying elasticity, for example

< in that the bladder has different thicknesses to thereby apply less or greater tension to the zones in the textile reinforcement. i In the case where the hollow body has protrusions or ,

shaped parts, the male part B can use the method shown in ■ patent to reproduce the desired profiles in the body.

After tensioning the reinforcement D, a suitable resin is introduced into the cavity Al in the mold via a conductor B4 placed '.in a suitable' position in the male part B, for example the resin can be a thermosetting resin such as an epoxy resin or f

a polyester. The resin can also be introduced beforehand into the hollow

<1>i

• the space Al in the mold after introducing the cap F into the cavity, especially when the cap F is made from a synthetic thermo-

plastic material to provide the outer surface of the hollow body. The binder resin that is injected into the cavity i is absorbed into the textile reinforcement D and reaches the structure j

■exposed to pressure from the elastic bladder. C it will take the form of the cavity Al. !;

,When the binder resin is polymerized and solidified, the 'pressure is relieved from the bladder C and the mold is opened and the helmet is removed from

' ■ • ■ ■in the skin part A and the textile reinforcement D in the helmet are baked in

jog fixed in the binder resin and held in a constant state of tensile stress. The outer surface of the body thus obtained is smooth and requires practically no finishing,

■as the surface is. colored as needed because as already j an-j-■given the outer cap F can be colored and/or provided with drawings etc.1. i 'i i

i i The hollow body and especially in the helmet obtained is complete: in all respects in that its outer surface is free from protrusions or sharp points,,,even if the textile constituting the reinforcement D consists of threads or filaments with

■ in limited flexibility, as is the case - for synthetic resins.

With regard to what is indicated for fig. 1, the same considerations also apply to the form according to<!>fig. 2 also with regard to the practice of the present method. In this case, the enlarged edges D1 of the reinforcement caps D will be arranged in a peripheral groove B3 in the shaped body B1 which also holds the fastening collar Cl. Attaching the caps G to the male part B in the mold enables the manufacture of the hollow body as the combination formed by the caps D and F-G can be attached as needed to the male part and the whole construction will always be able to engage easily in the cavity

A.

Based on the above stated is the purpose of the invention

to provide hollow bodies which are resistant to.

.mechanical stresses, especially shock stresses in such a way that the body's walls react elastically yielding'

, on the stresses resulting from the presence of textile-', the reinforcement which is present in a state of constant j

• tensile stress. :

<1>i

; . i: With regard to bringing the textile reinforcement D under tensile stress, this can be carried out in such a way that the woven dough or net textile is deformed in a direction which is essentially parallel to radials or essentially radials in plan of the obtained hollow body. The tensile stress can be applied to the layers that make up the textile reinforcement D in such a way that when you go from the inner layer the stress will vary gradually towards the outer layer, for example by varying the density of the fabric and/or the thickness of the yarn that makes up the different caps of the reinforcement, as well as by means of dimensions for these caps. It is obvious that the same criteria1 can be applied in the case where it is desired to apply an i

the essentially even and constant tension in the different layers of the textile reinforcement D.

Claims (18)

! I 1.. Method for the production of hollow bodies of f or-1 <1> reinforced resin, especially protective helmets, where I I the reinforcement consists of a number of woven and/or network textile layers baked in a resin,' ; .i characterized by arranging the layers of textile reinforcement (D) in an ar <v>" the two parts of the bn I form (A-B) and fixing at least part of the peripheral edges (Dl) of the reinforcement to the shape, impose a controlled tensile stress on the textile reinforcement and this is retained in the subsequent casting phrase, ,! i i especially during the polymerization and solidification and there after removing the thus obtained hollow body from the mold so that the textile reinforcement in it formed; body is incorporated and held by the resin in a ' state of tensile stress. j in 2. Method according to claim 1, characterized by imposing a tensile stress on the layers that make up the textile reinforcement D, which varies from the inner layer 1 towards the outer layers in the reinforcement and maintaining this tensile stress during the casting phase. 3. Method according to claim 1, characterized by imposing an essentially constant tensile stress on the layers that make up the textile reinforcement (D) and maintaining this stress during casting. ' in 4. Method according to claims 1 and 2, characterized by preshaping the textile reinforcement (D), for example in the form of a cap and fixing at least in a part of the legs (Dl) of each individual cap to one of the j parts (A-B) in the mold and hold them while stretching the reinforcement. 5. Method according to claims 1-4, characterized by imposing a controlled stretch i 'i tension on the layers of the textile reinforcement (D) at by means of a bladder (C) which is elastically deformable and j by means of a pressure fluid, preferably a liquid. | j in 6. Method according to claims 1-5, character sert by imposing the textile reinforcement (D) <1> In a tension less than the modulus of elasticity of the thread i or the yarn ' used in the production of text! il-,In the amplification. in ! Il 7. Method according to claims 1-6, character cert in that a number of woven textile caps (D) are used as textile reinforcement. whose edges (Dl) are at least partially enlarged to form^ ; an anchorage under tension .of the caps. ! . in 8. Method according to claims 1-7, characterized in that between the textile reinforcement i. (D) and the walls of the mold (A-B) at least one layer or film (F-G) is introduced which forms at least the external and/or internal surface of the hollow body. IN in 9. Method according to claim 8, characteris! pea in that it is reproduced beforehand on a film (F) ! colors and/or characters that will be transferred during casting to the surface of the molded hollow body. 10. Method according to claims 8-9, characterized in that as an outer film (F--G) a film of thermoplastic material is turned inside is worked and fixed to the structure of the hollow body during the casting operation. 11. Method according to claims 1-10, can be characterized in that yarn or fibers of natural and/or synthetic materials are used as material in the textile reinforcement (D), of which at least a part; is ! thermoplastic and which is incorporated into the combined | binding resin* in under casting. in 12. Mold for carrying out the method according to claims 1-11 comprising a female part that reproduces the negative shape . for the hollow body to be produced, c a r a k j-terized by means of fastening in the'least ! part of the edges (Dl) of the textile reinforcement (D) of at least part of the walls (C) of the part (B) in the shape ] is made of an elastically deformable material and provides gaps (C2) for a pressure fluid which> : I! deforms the walls and provides a controlled j <j> tensile stress to the textile reinforcement (D).. <:> 13. Form according to claim 12, characterized: in that its male part (B) is provided at its ends with a j peripheral groove (B3) which holds both the edges (Dl) of the caps of the textile reinforcement and the edges of an j elastically deformable bladder (C ) which stretches the hoods. 14. Form according to claim 12, characterized by a peripheral shoulder (A2) and a corresponding protruding part (B2) arranged at the edges of the opening of the hollow space (A1) in the female part (A) and the plate of the male part ( B). to firmly hold together at least part of the edges (Dl). of the caps (D) of the textile reinforcement and where the male part (B) is provided with at least one elastic bladder (C) ! to bring the caps under tension. 15. Hollow body of reinforced resin, in particular a protective helmet obtained by the method according to claims 1-10, characterized in that the reinforcement (D) is in the form of a woven textile or a net and is present under a state of tensile stress inside the binder resin for the reinforcement. 16. Hollow body according to claim 15, characterized in that its external and/or internal surface consists of layers (F-G) attached to the structure of the body and is capable of receiving protrusions from the surface i i e.l. formed by filaments or threads of texti• lfo1 r- ' !: the strengthening. in 17. Hollow body according to claim 16, characterized in that the external erve f flat layer (F) consists of the J at least of a laminate of a thermoplastic material1 which :' may be incorporated into the binder resin in the cavity , in the body... ' ■ ■ i 'I ! 18. Hollow body according to claims 16 and 17, character e rj i - i' cert. in that the external surface (F) is provided with desired designs and/or colors which are essentially reproduced as a result of the body's transparent surface. in