GB1295292A - - Google Patents

Abstract

1295292 Making collapsible tubes LECTRATUBE Ltd 18 March 1970 [18 March 1969] 14178/69 Heading B3A [Also in Divisions B8 and F2] An apparatus for forming collapsible laminated tubes comprises a rotatable mandrel, a source of metal foil layers, means for transferring the layers from source to the mandrel for them to be wrapped around a plastics tube mounted thereon, means for inducing heating in the metal foil whilst being transferred and means for pressing the layers around the plastics tube. As shown, one of a plurality of rotatable non- metallic mandrels carrying a plastics tube 4 is mounted on an intermittently rotating disc 2 Metal foil (e.g. tin or aluminium) 18 is supplied intermittently by rollers 16 and cut by blades 20, 22 into lengths 24 which are transferred to the mandrel by belt 8 and simultaneously heated by induction coils 14. The belt is powered by drive roller 10 and its tension adjusted by roller 12. Idler roller 6 applies pressure to the foil when wound on to the plastics tube to unite them. Roller 26 assists smoothing the foil and houses additional induction coil 28. Belt 8 may be replaced by a reciprocating plate and the coils 14 permanently attached thereto. Additional heating may also be provided by an infra-red heater placed above the belt 8 or plate and the coil 28. The metal foil layer 24 may be kept flat by the use of a porous belt 8 and creating a vacuum beneath it. The metal foil may be in laminated form having a roller or extrusion coating of a thermoplastic layer, e.g. polyethylene, the metal foil, a layer of paper and another layer of thermoplastic. The paper and foil may be joined by adhesive and the heat induced in the foil plasticizes the thermoplastic to facilitate bonding with the plastics tube at 4. This tube is preferably extruded and may be activated by a flame treatment or corona discharge to facilitate bonding. The completed tubes are removed from the mandrels when the disc has been rotated to another position.