DE3038795A1 - Windsurfing board - dished skins are glued up with overlapping edges laid over foam core and moulded together - Google Patents

Abstract

Windsurfing boards are produced by placing a preformed foam core between plastic or GRP dished skins which are then bonded together along their (pref. overlapping) edge. The core is one- piece or split along its mid-plane and has a groove all round its equator, the skins are glued up and placed into this groove; the edges of the skins are glued, they are applied and the assembly is placed in a mould. The cavity between core and skin edges, formed by the groove, is resin-foamed in situ, and the cured assembly is removed from the mould. Lightweight stable product with accurately bonded outer skins is obtd.

Description

Method of making sailboards

The invention relates to a method for manufacturing sailboards, in which a preformed core made of foam plastic in the outer walls forming half-shells made of plastic or GRP is inserted and the half-shells are glued together along their preferably overlapping edges.

In known methods of this type, the problem arises that the Foam plastic core enclosing half-shells to be glued together well. at The half-shells are so large preformed parts that despite the largest Care in their manufacture can not avoid that the with each other The edges to be glued are not so precisely aligned that a good one Bonding is guaranteed.

Even by inserting in support forms when gluing can not be make sure that the edges are exactly on top of each other when gluing, or inside each other grab, so that always with unclean gluing, shifted edge areas and leaky adhesive seams must also be expected.

It is also known to remove the half-shells after the adhesive has been applied to insert on the edges and their joining in support forms and the between the half-shells formed cavity with a foam plastic that a pressure that presses the half-shells against the walls of the support form is generated. This method not only has the disadvantage that the sailboards due to the required wall thicknesses of the half-shells and because of the solid foam plastic core assume an undesirably high weight, the inserted 'foam plastic can possibly also with displacement of the adhesive through between the edges Press the joints of the half-shells onto the outside of the half-shells, so that he presses between the outside of the half-shells and the support forlll grooves developed, which leads to a shifting of the adjacent edge areas of the half-shells leads. The consequence of such unclean bonds is that rejects are produced will.

The object of the invention is to propose a method according to which sail boards with low weight and high stability can be produced, their Half-shells clean together along their edges, avoiding scrap are glued.

According to the invention this object is achieved in that the one-piece or divided in the area of its median plane, along "his Provided the edge defined by its largest cross-section with a circumferential groove is, is placed in the coated with glue bowls that on the one another'zu Adhesive edges glue applied and the unit after joining the Half-shells is included in a supporting form that accommodates this, and that the Annular space formed by the circumferential groove between the core and the edge areas the shells is filled with a pressure-developing plastic foam and that the sailboard form after sufficient curing of the adhesives of the support is removed. The inventive method allows one in the shells to insert a prefabricated lightweight foam plastic core without being glued the edges of these enclosing half-shells leading to increased rejects would result. Because the plastic foam injected into the circumferential groove develops a targeted pressure that cleans the edges of the shells to be glued together presses against the supporting forms surrounding the shells. We the lower shell by a paragraph indented edge with an inner protruding lip, acts in particular, the pressure developed by the plastic foam inserted into the groove also on the inward-facing side of this lip, so that the edge of the upper shell, the one between the front of the edge of the lower shell and the upright The lip formed paragraph lies, neatly and tightly glued to the edge of the lower shell will.

The inserted foam plastic core has such great strength that it is able to support the half-shells and the plastic foam that has been injected can absorb pressure developed in the groove.

According to another suggestion, the problem posed is solved by that a hose made of elastic material is inserted into the circumferential groove, the after placing the shells enclosing the foam plastic core in the Support shape inflated and kept under overpressure for at least that long until the adhesives have cured sufficiently.

According to an inventive further development, it is provided that in the adhesive layer of fiberglass fabric connecting the half-shells to the foam plastic core or mats are inserted. An adhesive based on epoxy resin can be used as the adhesive be used. In this embodiment, the glass fiber fabric or formed by -mat reinforced adhesive layer a load-bearing layer that connects to the half-shells forms a laminate, so to speak, so that the thickness for further weight reduction the half-shells can be reduced.

The half-shells can be made from thermoformed plastic sheets made of thermoplai rule plastics, such as ABS, exist.

This avoids problems that would otherwise arise during manufacture of the half-shells made of GRP. A thickness of the half-shells of 1.0 - 1.5 mm and a thickness of the adhesive layer reinforced by glass fiber fabrics or mats of about 0.6 mm is conceivable.

According to a further inventive further development, it is provided that the foam plastic core consists of two core halves separated in its central plane consists of the tubular ones that are flush with one another in the assembled state Recesses are provided, each at such a distance from the surfaces end of the core halves that these ensure sufficient strength of these Walls are separated. The cavities lead to considerable weight savings, but without noticeably impairing the strength of the core. Appropriately the recesses are limited by curved walls that the surfaces of the Give core halves good strength. The recesses can be honeycomb be arranged.

To connect the core halves between the recesses located webs on the one hand with pegs and on the other hand with complementary recesses be given away. If a sufficient amount of adhesive is poured into the recesses, displace the pegs when they are joined together, so that they correspond to the filled Adhesive excess results in a good bond.

According to an advantageous embodiment it is provided that the core halves with aligned, longitudinal and ending in front of the surfaces Slit-shaped openings are provided, in which the longitudinal ends and standing on edge Bars made of rigid material are glued in. Such so-called stringers not only lead to an additional good connection between the core, they show also a large area moment of inertia atlr, so that the 'S.egeibretL a large Flexural rigidity is given around its transverse axis.

An embodiment of the invention is described below with reference to FIG Drawing explained in more detail. In this Fig. 1 shows a cross section through in a Support form inserted half-shells with a foam plastic core enclosed by these, FIG. 2 shows a cross section corresponding to FIG. 1 with one in the circumferential groove of the core, and FIG. 3 shows a perspective view of a part one core half.

As can be seen from Fig. 1, the support Eorm is in the mold halves 1, 2 an upper half-shell 3 and a lower half-shell 4 inserted. The lower half-shell 4 has a shoulder on its edge that passes through the end face 5 of the edge and a retracted upstanding lip 6 is formed. The upper shell 3 butts with the end face 7 of its edge stump on the Sti side 5 of the edge the lower shell 4, so that the edge of the upper shell 3 in the through the front side 5 and the raised lip 6 is formed level.

Before the half-shells 3, 4 are joined together, their inner walls are has been provided with an adhesive application 8. Then the core halves 9, 10 of the foam plastic core divided in its middle plane onto the adhesive layers 8 pressed on. The core halves are aligned with each other with recesses 11, 12 provided, the one from Plg. 3 visible honeycomb pattern can form. The front sides the webs 13 of the upper core half are provided with pins 14 with corresponding Recesses 15 in the end faces of the webs 16 of the lower core half 9 are aligned. Before the core halves are joined together, adhesive is filled into the recesses 15. After the between the end face 5 of the edge of the lower 'half-shell 4 and the step formed by the protruding lip G has been filled with glue, the upper shell 3 is placed on the lower shell 4. In the area of the raised encircling the lip 6 is the foam plastic core formed by the core halves a circumferential groove 17. After inserting the joined half-shells 3, 4 in the support mold 1, 2, the groove 7 is injected with a foam plastic, which exerts a pressure on the upstanding lip 6 in the direction of the arrows. By this pressure is applied to the lip against the inner area of the edge of the upper half-shell 3 pressed so that a tight and clean bond is given.

In the circumferential groove 17 kr in also, as can be seen from Fi Fig. 2, a tube 18 made of elastomeric material can be inserted. This will inflated in the manner shown after placing the half-shells in the support mold 1, 2, so that the hose exerts a pressure on the upstanding lip 6 and a good one Bonding of the edges causes.

To support the half-shells 3, 4 Glass fiber fabric 'or -mats are inserted- so that jlcichsam' in the form of a Laminate an additional load-bearing c) surface layer L c'rc; ibt.

The core halves can be provided with longitudinal slots 19, 20 and 21, 22 are provided, are glued into the so-called stringers 23, 24, the give the sailboard additional flexural rigidity around its transverse axis.

The foam plastic core thus consists of two in its central plane separated core halves, which are opposite in the assembled state, aligned, tubular Ausnehmunqen are provided which through Bars are separated from one another, which come to lie congruently on top of one another. The webs have pegs and recesses and / or tongue and groove that oppose each other point. The cavities are designed to accommodate liquid adhesive can, the cavities in each case at such a distance in front of the surfaces of the core halves so that they can be removed from them by a sufficient step or Vault-like floor-ceiling formation ensuring shock resistance are separated.

The cavities are protected in themselves and hermetically sealed against each other closed because they are inside the glued foam core halves.

L e r s e i t e

Claims (9)

Method for producing sailboards Patent claims: Method for the manufacture of sailboards, in which a preformed core made of foam plastic inserted into the half-shells made of plastic or GRP that form the outer walls and the half-shells along their preferably overlapping edges are glued together, characterized in that the one-piece or im Area of its median plane divided core, which along its by its largest Cross-section defined edge is provided with a circumferential groove into which an adhesive application provided shells is inserted that on each other to be glued edges of the half-shells adhesive applied and the unit after Assembling the half-shells included in a support form that accommodates them is, and that by the circumferential groove formed annulus between the core and the edge areas of the shells with a pressure-developing plastic foam is foamed and the sailboard after sufficient curing of the adhesives is removed from the support form. 2. Process for the production of sailboards, in which a preformed Core made of foam plastic in the half-shells forming the outer walls Plastic or GRP is inserted and the half-shells along their preferably each other. overlapping edges are glued together, characterized in that that the one-piece or in the region of its central plane divided core, the longitudinal its edge defined by its largest cross-section with a circumferential Groove is provided in which a tube made of elastic material is inserted into the peelings coated with glue are placed on top of each other Adhesive applied to the edges to be glued and the unit after joining the half-shells is enclosed in a supporting form that accommodates this, and that inflate the hose with compressed air and maintain the overpressure for at least that long until the adhesives have cured sufficiently. 3.. Method in particular according to one of claims 1 or 2, characterized characterized that in the connecting the half-shells with the foam plastics Adhesive layer of glass fiber fabric or mats can be inserted. 4. The method according to any one of claims 1 to 3, characterized in that that the half-shells made of partially drawn plastic plates or plates made of GRP or Laminates are made. 5. The method in particular according to one of claims 1 to 4, characterized characterized in that the Schatmkunststoffkern of two separated in its central plane Core halves, which are aligned with each other in the assembled state, tubular recesses are provided, the rope at such a distance in front of the surfaces of the core halves that these end by a sufficient Walls ensuring strength are separated. 6. The method according to claim 5, characterized in that the recesses are limited by curved walls. 7. The method according to claim 5 or 6, characterized in that the Recesses are arranged in a honeycomb shape. 8. The method according to any one of claims 5 to 7, characterized in that that the webs located between the recesses on the one hand with pins and on the other hand are provided with recesses complementary to these. 9. The method according to any one of claims 5 to 8, characterized in that that the core halves with each other aligned, longitudinal and in front of the surfaces ending gap-shaped openings are provided, in the longitudinal and edgewise standing Bars made of rigid material are glued in.