A method and apparatus for near end of the tube, temporarily can be brought in the deformable condition, in particular the tube of thermoplastic plastic such as polyvinyl chloride, to produce an internally calibrated extension in such a way that the tube is again narrowed to smaller diameter than the enlargement in the direction towards the nearest touching.

摘要

997,552. Moulding tubes having widened ends. A. WIEDENOFF, [trading as KUNSTSTOFFWERK GEB. ANGER G.m.b.H. & CO.] Jan. 15, 1962 [Nov. 22, 1961], No. 16335/64. Divided out of 997,551. Heading B5A. A widened portion is produced in the vicinity of the end of a tube of plastics material by pushing and consolidating the tube end over a collapsible core and subsequently collapsing the core and removing it. The tube 8, Fig. 1, to be widened is gripped in a chuck 6, and its end heated by a device 22 (Fig. 3, not shown), to soften it and then pushed over a lubricated core 2 having an annular beading 23. A sizing cylinder 3 is now moved over the tube end by an hydraulic cylinder 16. The exposed portion of the tube 8 is now cooled by a liquid spraying device (not shown) and the cylinder 3 removed from the tube end which is similarly cooled. Finally, the core 2 is collapsed by the actuation of an hydraulic cylinder 18 which withdraws a core portion 41, Fig. 6, carrying pivoted segments 37 from a core portion 30 carrying pivoted segments 35 adapted to interleaf with the segments 37.