GB1363469A - Method and apparatus for making hollow tubing - Google Patents

Abstract

1363469 Automatic control of position ARMSTRONG CORK CO 22 Dec 1971 59803/71 Heading G3R [Also in Divisions B5 and F2] Long lengths of foamed elastomeric tubing comprising foamed plastics 92, Fig. 4A enclosed in a pair 94, 95 of flexible sheaths are constructed on a long mandrel 17 which is fixed at one end, there being control means for detecting and correcting any flexure of the mandrel. The foam 92 comprises polystyrene or polyurethane, and the sheaths 94, 95 comprise paper, foil or plastics sheets. The sheets 94, 95 are lapped and the inner sealed by adhesive, heat, or a hot melt technique when a heat adhesive strip is fed between the lapped edges. Uses include cylindrical or prismatic pipes, ducts or pipe thermally insulating covers. For the latter, the finished tubing is slit longitudinally to form an open side and a hinge (see Fig. 9, not reproduced). General layout. The hollow mandrel 17 is supported at its left end Fig. 1, and, until some tubing is formed, by moulds 52. Flexible sheet material 26 is folded tightly around the mandrel 17 by a guide 25, and heat sealed by an element 25a and roller 25b. Flexible sheet material 30 is folded loosely around the mandrel by a guide 29, and simultaneously foam material is fed by a nozzle 33 into the space between the two sheaths. Foaming and curing is carried out within chair conveyed moulds 52 in an oven, the moulds serving to pull the tubing along the mandrel 17. The flexure of the mandrel is detected by a laser 22 and photo-electric cell 51, which control an aligning device 37. The mandrel; aligning. The aluminium mandrel 17 is supplied internally with warm air 24 that emerges through perforations in the mandrel to aid movement of the tubing. The mandrel 17 with the tubing is engaged by a grooved roller 37 mounted on a spindle 38 and displaceable horizontally and vertically by respective wheel cranks and worms 40, 39. The mandrel internally supports a roller 49, Fig. 7, which opposes roller 37; displacement of roller 37 with respect to roller 49 flexes the mandrel appropriately. An auto reflecting tooling laser 22, Fig. 1, directs a beam internally of the mandrel 17 on to the photo-electric cell 51 comprising a quadratic arrangement X, X', Y, Y', Fig.11. The outputs of opposing pairs XX' and YY' are fed to bridge control circuits 100, 101 that actuate reversible motors 100H, 101V to position the aligning roller 37, Fig. 7, on flexure of the mandrel. Alternatively, the bridge controls 100, 101, Fig.11, deflect meters from zero, the return to zero being effected by manual control of the roller 37 Fig. 7.