GB1362875A - Retractable core for hollow members - Google Patents

Abstract

1362875 Foldable frame for making vessels by winding HOUILLERES DU BASSIN DU NORD ET DU PAS-DE-CALAIS 4 Nov 1971 51429/71 Heading B8G A foldable frame for manufacturing hollowopen-ended members by winding fibres impregnated with synthetic resin thereon comprises axially aligned shafts 1, 2; a plurality of beams 12 coupled to the shafts 1, 2 by struts 14, 17 such that when the shafts 1, 2 are moved apart the beams 12 move radially inwards to cause the core to collapse; and means for ensuring that the frame is rigid when expanded. A plurality of curved plates 19 extend around the beams 12 to form a tubular shell thereon. Each plate 19 has a width l 1 such that it can eventually be withdrawn out of one of the open ends of the wound member. Triangular end sectors 20 that combine to cover the ends of the core, interconnect the beams 12 with discs 21 on the shafts 1 and 2. The length 12 of the major base of a sector 20 is slightly smaller than an open end of the wound member. The means for ensuring that the frame is rigid when expanded are pins that are additional to the pivot pins interconnecting the struts 14 with the shaft 1; and pins that are additional to the pivot pins interconnecting the struts 17 with the beams 12. A universal joint 22 on the shaft 1 enables the structure to be coupled to drive means. A motor 26 coupled to the shaft 2 enables the structure to be rotated in a manner preventing the synthetic resin from dripping whilst the shaft 1 is de-coupled from its driving source and the wound body is moved into a drying oven. The frame may be coated with a thin layer of a thermosetting synthetic resin; followed by a layer of glass fibres impregnated with a synthetic resin; followed by a layer of filaments impregnated with a suitable resin.