| 摘要 |
1,243,123. Seaming non-metallic sheet material. L. R. INDUSTRIES Ltd. 14 Nov., 1969 [19 Aug., 1969], No. 41322/69. Heading B5K. [Also in Division A5] A contraceptive sheath is manufactured by cutting and welding two superimposed layers of synthetic thermoplastic film material along a line conforming to the profile of the sheath body and subsequently cutting the two layers to form the open end of the sheath. As shown, the film 1 in the form of a flattened seamless tube is fed intermittently from a supply reel 2 by a feed roller 3 on to an endless conveyer belt 5 the upper run 5A of which passes over a support plate 6. A cutting and welding tool 7 is mounted on pistons 15 for vertical reciprocation above the plate 6 and is formed with a rib 8 conforming to the profile of the sheath to be formed. The rib 8 has a cutting edge 8A and a welding face 8B spaced therefrom so that the film layers are first cut and then, immediately thereafter, welded. The rib 8 is heated by connection by leads 9 to a source of radio frequency electric current. An unheated cutter 11 is provided on the tool 7 and, during a cutting and welding operation, severs the sheath body formed in a previous welding operation. The blade 11 is cooled by the circulation of water through a line 16 to internal passages in the plate 6. In modifications, the superimposed film layers are formed by longitudinally folding a single thickness web of a plough (14), Fig. 5 (not shown), or by supplying two separate superimposed webs. Specified plastics materials are polyethylene, polypropylene, ethylene-propylene copolymers, polyethylene terephthalate, polyvinyl chloride, polyvinylidene chloride, nylon and polycarbonates. |
