FR2576250A1 - REINFORCING ELEMENT FOR COMPOSITE MATERIALS SUCH AS CAMPING CARAVAN DOORS, TANKS OR OTHER - Google Patents

Abstract

A. REINFORCEMENT ELEMENT FOR COMPOSITE MATERIALS SUCH AS CAMPING CARAVAN DOORS, TANKS OR OTHERS. B. ELEMENT OF REINFORCEMENT CHARACTERIZED IN THAT IT CONSISTS OF AT LEAST ONE MADE-UP TEXTILE PRODUCT, AT LEAST PARTIALLY STAMPABLE, THAT IT CORRESPONDS BY ITS CONTOUR TO THAT OF THE PART TO BE BUILT, THAT IT CONSISTS OF WATER LESS ONE PIECE AND IT IS STRETCHED OVER AT LEAST ONE CORE BY TIGHTLY SURROUNDING ALL PARTS THE LATTER BY APPLYING CLOSELY. C. THE INVENTION RELATES TO REINFORCING ELEMENTS FOR COMPOSITE MATERIALS SUCH AS CAMPING CARAVAN DOORS, TANKS OR OTHERS.

Description

"Reinforcing element for composite materials such as doors of

  The invention relates to a reinforcing element for composite materials which are manufactured by the

  vacuum injection method (VI).

  It is known that small and medium series of construction parts can be manufactured by the vacuum injection method. It is known, on the other hand, that thin-walled laminates can be made

  or thick and sandwich pieces. He is particularly

  It is therefore economical to manufacture polyester and polyurethane sandwich construction parts by the vacuum injection method. We use here as products of

  polyurethane foam, polyurethane resins, polyurethane

  ester fluids, or other synthetic resins and nonwoven webs of continuous glass fibers as reinforcing material. What is most widespread is the use of continuous fiber sheets as reinforcement material, these sheets having good permeability to the resin, as well as because of their structure, they exclude the separation of fibers

  by flotation. If these sheets or matts are too strong

  If compacted, for example, glass fiber sheets stacked with a binder, it is necessary to put an additional resin-permeable lining, for example a packing cloth, where it is necessary to practice in the core. foam additional ducts for the

passage of the resin.

  It is also known from DE-OS 19 59 151 and DE-OS 20 12 733 that reinforcing fibers can be used in the form of knitted or knitted fabrics. It is known, on the other hand, the use of bulky sisal fiber plies as reinforcing materials and, at the same time, as a ply allowing

the passage.

  It is preferable, by the vacuum injection method, to produce structural parts which have no structuring, "SURF" boards by

example.

  For sandwich construction parts that

  are mainly intended for garnishes and iso-

  tion and which are, therefore, less subject to

  mechanical stresses, the main problem is to arrive at a uniform wall thickness as thin as possible, because this quality has important effects on the weight, the stability of the shape, the value with the use, the quality of surface and the cost. The search for a solution to this problem is of particular interest for the construction of bodywork. The continuation of the penetration of the vacuum injection process, which can be mechanized strongly, in the construction of bodies, for example, in caravans camping is hampered by the requirements that oppose reciprocally the value of use and manufacturing possibilities. The search for lightweight, double-bent sandwich construction parts with relatively large inserts of foam cores, comes up against the limits of sandwich manufacturing possibilities, with thin cover layers, by the vacuum injection process because the mattes of endless fibers only allow the manufacture of walls of a relatively large thickness and must, without exception, be placed by hand in the molds. All reinforcement materials known hitherto prevent full advantage of the vacuum injection process for industrial manufacture, in particular for the manufacture of sandwich elements made of polyester, polyurethane double curvature, for the reasons indicated below. after:

  As embossable tablecloths, we know only

  tablecloths or mattes of endless fibers, as well as knitted fabrics and with certain reservations the

fabrics worked in stitches.

  With endless layers of fibers, only laminates can be produced because of their construction.

  of a thickness of 3 mm and more. In areas where

  large partial deformations, the sheets or mattes of endless fibers are stretched into a small number

  groups of fibers and consequently lose in these areas

  their strengthening action. Pieces constructed in sandwich with endless sheets or mattes of fibers are, therefore, relatively heavy, sometimes also in connection with a coating with a gel or a surface layer, because of this, the thickness of the laminate will be

further increased.

  Webs of continuous fibers, knitted or knitted fabrics, and pieces forming thinner fiberglass surfaces which are unsuitable for stamping, such as, for example, stacks of staple fiber webs; glass involves a binder, and the products "Malimo" trademark must be adapted, by numerous precise cuts to the body of double curvature foam, The locations of the overlays, which are formed then, form channels in which the resin penetrates more quickly , and

  causes the formation of islands that are not impregnated.

  It is then necessary to make alterations that

  decrease the quality and are expensive.

  The hand-laying of the reinforcing material into the mold and the coating of the foam core with the reinforcing material requires a lot of care, as they must be gap-free and free of wrinkles. The edges require special care, where there must be no excess or lack of material. It is in this phase that the subsequent quality of the composite material is fixed. This stage of the work takes a lot of time and prolongs the occupation time of the mold at the expense of

  the vacuum injection operation itself.

  The current reinforcement materials have, moreover, the disadvantage that they require an implementation of materials that technically do not obey

strict rules.

  On the other hand, it is known that one can make

  closed hollow bodies from plastic material reinforced with glass fibers. For example, tanks are mounted on molded parts, or rolled up according to different processes. There is a difference here between unpressurized storage or transport tanks and pressurized tanks. The reservoirs

  under pressure are manufactured by the winding process

wire.

  Closed hollow bodies made of fiberglass-reinforced plastic are becoming more and more

  important as lightweight building elements

  tives. Depending on the mechanical requirements, they will be stiffened in part by rings and / or lengths or in other areas, will be made in sandwich. Known hollow bodies are, for example, tanks which are built by mounting from two halves of the construction. The disadvantage of these closed hollow bodies is that they can be manufactured only by mounting mold parts, where, as described, the locations of

junctions are the weak points.

Purpose of the invention.

  The object of the invention is to propose a reinforcement element requiring little material which makes it possible to give the vacuum injection process a more rational form and which makes it possible to reduce the amount of

  material used in this process.

  The object of the invention is to propose an at least partially embossable reinforcing element for composite materials which allows the manufacture, with

  complicated shapes, a thinner laminate, sufficient

  solidly solid. This result is obtained by means of a reinforcement element for composite materials which according to the invention consists of at least one product

  made-up textile, at least partially embossable.

  This textile product is made of at least one piece and is stretched over at least one core on which it applies

close to all sides.

  It is advantageous if the embossed textile product, made up, is a knit or a product

worked in mesh.

  As a material for the made-up prodtit,

  hardenable, chemical fibers are preferably used

  such as polyamides, polyester and / or glass fibers.

  In a bed, the reinforcing element consists of at least one textile product made at

less partially stampable.

  Due to the weakness of the thickness of the reinforcing element, it is also possible to arrange

several beds.

  On the other hand, the reinforcing element can

  consist of several beds made of similar materials

different or different.

  The core on which the reinforcing member is stretched may be generally a foam block. However, it has also been found that composite materials can be made with a hollow body as the core, for example an inflated polyethylene bag. The invention ensures the manufacture of materials

  extremely lightweight composites, while providing

  This process is extremely advantageous from the point of view of saving material and makes it possible to organize the vacuum injection process in a more rational manner, the reinforcing element being previously made outside the mold in a special workstation. In this preliminary preparation work, we can use the most complicated forms, by means of a work of approximation, of an ad hoc accessory,

  partial welding, gluing or stapling.

  The times of occupation of the mold will be

following greatly reduced.

  The high drawability, in particular

  tying made knitted objects makes it possible to

  fold the shapes of building elements into composite materials. Thus, for example, sudden reinforcements which are not suitable for vacuum injection in a surface, or very weak radii may be

shaped under these conditions.

  Other possibilities for achieving the elemen-

  reinforcement consist in the choice of wires,

  mesh and in the weight per unit area.

  Thanks to the three-dimensional extension possibilities

  of the reinforcement element according to the invention, which can be found both in the macrogeometric zone and in the

  in the microgeometric zone, we obtain a permeability

  lity to the resin that will be difficult to overcome.

  The implementation of the reinforcement element according to the invention in the manufacture of hollow bodies makes it possible to arrive at an entirely new technology.

for these products.

Examples of realization.

  First example: Manufacture of a camping caravan door.

  As a starting material for the element of

  forcing stamping, we use "Wolpryla" trademark.

  The shaping is performed on a trimming machine.

straight line motor.

  The machine is set for training

mesh right-right.

  The mesh strength corresponds to the resistance

  known from the clothing industry.

  The surface weight of the produced knit is

at 280 g / m2.

  The material produced by the meter is cut into pieces

following a stencil.

  The cut is made in large quantities in the form of the unwound surface of the finished part, taking into account possible reserves and significant deformations.

(openings or piqGres).

  Sewing of the parts of the reinforcement element

  This is done on a three-threaded sewing machine. During cutting and sewing, care should be taken to place the opening necessary for the subsequent introduction of the foam core in a place which allows

  then close the reinforcement element easily.

  The closure of the reinforcing element after it has received the foam core takes place by hand, by

  way of some stitches.

  For larger openings inside the parts that will be completed afterwards (eg a look in the caravan door) the foam core will be provided with a recess, and the reinforcing element will be connected after sewing, by means of an adhesive for

  textiles at the desired location which will be stamped at the same time.

  The foam core, made up, thus obtained will be

finished in a finished piece.

  Second example: Making a large tank

  dimensions, with relatively narrow neck.

  As a starting material for the reinforcing element, a twisted glass fiber yarn (ES 9 68 tex Z X ZS 100 - T 10 - B 1) will be used. The shaping is carried out with several strands on a straight machine knitting machine. The machine will be put into operation for

  a right-to-right mesh formation, making sure

  especially on the guide elements of the wire, for

  to obtain a loose and very deformable knitting.

  The weight of the knit per unit area is 450 g / m 2. The material produced is cut into beds following a pattern. We will put two beds one on the other in the

  offset, and sew them with a lockstitch machine.

  The beds thus built will be sewn in the shape of a bag.

  Because the beds are placed one over the other with an offset, it happens that the seam that gives the shape takes only two thicknesses and that no rigid seams are formed. We introduce in this element

  reinforcement with two beds, a rubber balloon

  flable to which a pipe is attached. The rubber balloon is slightly inflated, and the reinforcing element is pulled on without making a crease. The whole is then brought into a mold. Special attention should be paid to the areas of the edges of the mold so that it does not occur

  no pinching between the halves of the mold.

  The rubber balloon is then inflated by means of the pipe passing to the outside at an airtight point,

through the mold.

  The reinforcement element then applies exactly

  on the inner wall of the mold.

  The pressure in the rubber ball must

  be given to the depression used during the operation.

  ration (Pressure in the bag-sheet = 133.32 Pa.103.

  Depression = 399.96 Pa.102 Pa in the mold).

  The known vacuum operation is then performed. The rubber balloon is then removed from

  the finished piece, and possibly used other times.

  It can however also be left in the finished part.

RE V E N D I C A T IO N S

  1) Reinforcing element for composite materials, characterized in that it consists of

  less a textile product made, at least partially

  it can be embossed, that it corresponds in outline to that of the part to be built, that it consists of at least one piece, and that it is stretched over at least one core, closely surrounding the latter on all sides

by applying it closely.

  2) Reinforcing element according to the

  cation 1, characterized in that the textile product confection

  embossed, is a knit or a material

worked in mesh.

  3 0-) reinforcing element according to the

  cation 1, characterized in that the fabricated textile product, embossable, is preferably made of chemical fibers, such as polyamide, polyester and / or

fiberglass.

  4) Reinforcing element according to the

  cation 1, characterized in that it consists of at least

  a bed of a manufactured textile prdouit, emboutissable.

   Reinforcing element according to claim 1, characterized in that it comprises several beds

  a textile product made, embossable.

  6) Reinforcing element according to the

  cation 1, characterized in that it consists of beds of similar or different materials, or materials

differently shaped.

  7) Reinforcing element according to the

  cation 1, characterized in that the core is a body

foam and / or hollow.

  8) Reinforcing element according to one of

  1 or 2, characterized in that the body

hollow is inflatable.

  9) Reinforcing element according to any one

  of claims 1 to 3, characterized in that the

  Inflatable hollow body is a rubber ball.