Shell mould to manufacture windmill blades and pattern so constituted

Abstract

The scope of this invention is the manufacturing of a new shell mould of a braced constitution by randomly distributed ribs, which is used for the manufacturing of windmill blades, as well as the disposition and conformation of the fabric constitutive fibers and the plies used in the constituted pattern. The loads supported by the structure and the deformations produced during curing process are absorbed by the ribs, which are distributed along mould and displayed according to the weight each of them sustain. These ribs sit on a composite bed, remaining screwed and bonded to it. This distribution of the ribs allows the introduction of an air circulation channel inside mould, whose shape is adjusted to blade profile. The air circulation is uniform and unexpected dilatations are avoided because they are absorbed by the braced structure that produces an accordion effect. With reference to the predictable deformations, these are absorbed in the lower mould with the degrees of freedom achieved by the kneecaps of structure legs and in the upper mould by the skates joined to the struts of the Flip-Over Device. A second topic covered in this invention is the use of plies joined together forming a thicker and more consistent layer. The formation of these plies is achieved by a fabric whose filaments are entwined sinusoidly and is based on a weft of fibers made up of short strings.

1 .- Shell mould to manufacture wind power generator blades and pattern so constituted made up of two composite parts that form the blade profile, with an upper bed ( 1 ) immersed in the upper mould ( 2 ) and another lower bed ( 3 ) placed in the lower mould ( 4 ); this mould has a flip-over device ( 6 ) that allows mould to reach the open and closed positions; the introduction of hot air into the bed is carried out by several conduits geometrically adaptable to the blade shape, circulating from the root up to the tip through the central conduits ( 10 ) & ( 11 ), going through a first skin ( 7 ), an intermediate core ( 9 ) and some holes drilled thru the second skin ( 8 ), and returning through the front lateral conduits ( 12 ) and the rear lateral conduits ( 13 ), these conduits being stiffened by ribs braced over a composite bed, being screwed by the corresponding fasteners ( 25 ) and then bonding the kit formed by the ribs and the composite sheets ( 26 ) using an adhesive ( 27 ):  
     
     
         2 .- Shell mould according to first claim, in which the glass fiber plies forming the laminate used to manufacture the beds of the pattern are very thin and made up of several layers, each ply ( 27 ) being based on a network of fibers ( 29 ) made up of a plurality of entwined strings, so that one fiber ( 29 ) is formed by a group of strings ( 30 ) joined together and interweaved, and with the fibers of each ply ( 28 ) displayed perpendicular to the adjacent ply.  
     
     
         3 .- Shell mould according to first claim, whose ribs are formed by a generally rectangular shaped frame with two protruding edges that are inclined obliquely and ended by occluded flanges ( 21 ) that borders the front conduit ( 12 ) and the rear conduit ( 13 ). Some ribs include several reinforcing lateral stringers ( 20 ) and (a) complementary element(s) by way of pin ( 22 ) applied to the flip-over device.  
     
     
         4 .- Shell mould according to previous claim, which as well as the supports by way of pin ( 22 ) that exist in the upper semi-mould ( 2 ), includes some lateral supports ( 23 ) that are displayed by way of suspenders from each side of the corresponding ribs. Several fasteners are formed by supports ( 24 ) located at the edges of the mould, which branch off over the occluded flanges ( 21 ) of the ribs and come to an end in several skates ( 16 ).  
     
     
         5 .- Shell mould according to third and fourth claims, whose lower semi-mould ( 4 ) and metallic structure is formed by a series of legs ( 31 ) distributed along both laterals and joined to the base structure ( 33 ), which is made up of several horizontal sheets that are joined to the mentioned legs ( 31 ) by kneecaps ( 32 ) that can absorb any possible displacement.  
     
     
         6 .- Shell mould according to first claim, where the conducts bordering mould are not redundant but structural, and which has a structure braced by ribs that absorbs the elongations distributed at both sides of the rib without provoking displacements or transmitting the load.