| 摘要 |
1,170,904. Making plastics sheaths; seaming non-metallic sheet material. ABEL MORRALL Ltd. 9 Jan., 1967 [14 Jan., 1966], No. 1781/66. Headings B5D and B5K. [Also in Division B8] Spaced blades 18 (Fig. 2) first form simultaneous welds between two superimposed layers of thermoplastic material, and a second set of welds, intersecting the first, is then formed by spaced blades 20, the welds being such that the closed figure or figures formed by the seals can be torn out of the surrounding material. In the machine illustrated the blades 18, 20 are highfrequency welding electrodes pressed into the material to reduce it. A cushion formed of sheets 26 of different electrical characteristics from the polyvinyl chloride forming the sheets 10, 11 serves as a cushion during welding. The sheets 10, 11 are fed intermittently below the welding blades 18, 20 which are disposed to form a sheet of sheaths 25 (Fig. 6) which is then punched to form portions 27 from which the welds have been cut away, and which have suspension holes. The sheets are then torn into strips comprising each a single row of sheaths, and the end portions 27 are flexed in alternate directions by paddles 29 to make them easy to open. One of the two flaps forming the extensions 27 may be cut away, the other being either folded in or used for suspending the sheet. One of the sheets may be opaque, and the other transparent, and one may be highly polished so that it clings to itself when folded. The sheets are fed by reciprocating grippers (23) (Fig. 1, not shown). |
