GB1312019A - Tubular fibre preforms and methods and machines for making same - Google Patents

Abstract

1312019 Moulding by spraying STRUCTURAL FIBERS Inc 24 Aug 1971 39657/71 Heading B5A A fibre reinforced preform, Fig. 1a, comprising a tube 10 closed at one end by an integral wall 12, is formed by directing chopped fibre on to a rotating former 26, Fig. 1, having apertures through which a vacuum is applied to hold the fibres and by spraying the fibres with a thermosetting resin to join the fibres without filling the voids between them. The fibres are generally randomly orientated but with a predominant orientation along a spiral around the tube 10. A filament may be wound round the tube 10 for additional strength. The porous preform is subsequently made into a tank or pressure vessel by completely impregnating it with epoxy resin, placing the preform in a mould which closely conforms to its exterior, and inflating a bag within the preform to compress its walls while the epoxy resin is heat cured. In the embodiment the former 26 may take the form of Figs. 4 and 6 where support 65 has rods 68 mounted on plate 66 and carrying a perforated hemispherical former part 71. A cylindrical part 74 carrying lugs 76 is joined along a longitudinal seam by pins 80 to lie around the support 65. In the form of Fig. 7 the former is in two parts 102, 103 separable along a plane indined to the cylinder axis. Part 103 has lugs 109 and part 102 a mounting plate 101. The machine for moulding the article, Figs. 1, 2, comprises a tube 24 rotatable by motor 29 relative to fixed tubes 31, 37 through which a vacuum is applied. The former 26 is attached by its mounting plate 66 or 101 to the rotatable tube 24 and lies within an openable oven 54. As shown in Fig. 2 there are two tubes 24 and associated apparatus alternatively connected to the vacuum system by flap 38. On the left of Fig. 2 the oven 54 has been closed by sliding the top 61 over the former 26 and pivoting the casing 56 to enclose the former. Glass fibre 82 is cut up and directed on to the rotating former 26 by choppers 44, 46 and the thermosetting resin is sprayed by nozzles 51, 52 carried on arm 53. The choppers and nozzles are mounted on a frame 41 suspended from and driven back and forth along a beam 39. The arm 53 is pivoted to frame 41 so that the nozzles can be moved out of the way to close the oven. After a layer of resin and fibre has been deposited on the former 26 a single filament may be wound round the layer by a filament metering device 111 travelling along the rotating former. The article is then cured by burners in oven 54 after which actuators 78 move stripper ring 77, which engages the projections 76 or 109 on part of the former, to separate that part from the other part and facilitate removal of the article.