GB1293019A - Improvements in or relating to the manufacture of tubes of fibre-reinforced plastics - Google Patents

Abstract

1293019 Winding tubes KUNSTSTOFFBURO PORTA GmbH & CO KG 16 Feb 1970 [20 Feb 1969] 7400/70 Heading F2P A process for producing fibre reinforced plastics tubes comprises delivering fibre blanks 21, e.g. glass or polyester fibre fleece, and/or webs of interlaced rovings, which may be drawn from a magazine reel 10 and sheared to size on a table 12, to a winding mandrel 22 in the dry state to be wound and impregnated with plastics and subjected to pressure and friction by roller 24 during winding. The width of the blanks corresponds to the required length of the tubes and the length of the blanks may be equal to the circumference of the tube if there is to be a single reinforcing layer or a multiple of the circumference if more layers are required. A set of feed rollers 19, 20 may be used to guide the blanks. As shown, an apparatus for producing the tubes comprises a roller 24 driven by the same mechanism 28 as the mandrel 22 and adapted to rotate at a peripheral speed different from that of mandrel 22, so that the wound tube is smoother at the surface. To this end, the drive may also be so programmed that during the last few revolutions of the winding mandrel, the roller 24 is stationary. The roller 24 partly dips in a tank 26 containing liquid plastics material, e.g. a casting resin, which is conveyed to the mandrel 22 for impregnation of the wound mat. The plastics material if thermosetting, is cured before the wound tube is disengaged from the mandrel. The mandrel itself is mounted for rotation on swivel supports 30 which have limiting stops 34. A method of producing tubes with internal threads is described wherein plastics impregnated fibre rovings are wound into a threadmoulding profile on a mandrel until the surface thereof is flush, and before this cures the required wall-thickness of the tube is built on the mandrel so prepared. The mandrel is finally screwed out, &c. to facilitate this it may initially be treated with a release agent. A method of producing tubes with external threads is illustrated (Figs. 3a, 3b, 4a and 4b, not shown) wherein a thread-moulding roller temporarily carrying spiral fibre rovings is used to transfer the rovings to a semi-cured tube to form helical threads on the tube. Tubes of the invention may be used in chemical plants; tapered cylindrical tubes may be wound which find use as telegraph masts.