| 摘要 |
795,154. Making collapsible containers. TUBOPLAST SOC. ANON. Dec. 2, 1955 [Dec. 28, 1954], No. 34582/55. Class 87(2). [Also in Group XVII] A preformed thermoplastic tubular body 20 is held fixed between a mandrel 56 and a mould 42, the tubular body 20 being in contact with a cylindrical portion 48 of the mould and having its margin 30 folded over inwards by a curved profile 46 and a frusto-conical surface 44 of the mould. A pin 64 on the mandrel 56, engaging in a socket 54 in the mould, ensures that a space is left between the mandrel and the mould. Into this space hot molten thermoplastic material is injected through channels 66 to form a head-piece which fuses with the margin 30 of the body 20. The extremity of the margin 30 is blunt, that is, it is not reduced down to a knife edge. The thermoplastic material may be polythene or polyvinyl chloride. |
