| 摘要 |
1,158,228. Seaming non-metallic sheet material. L. DOYEN, and L. DOYEN. 6 Dec., 1967 [12 Jan., 1967], No. 55525/67. Heading B5K. A machine for welding thermoplastic materials comprises a jaw constituted by a heatconducting bar 2 which is traversed continuously lengthwise by a hot liquid or pressurized steam at constant temperature through a duct 3 and by a cold liquid through a duct 5 at the end of each welding cycle, the duct 5 being disposed near to the welding surface 4 of the jaw to enable subsequently the welded materials to be unstuck easily from the jaw. The hot liquid, e.g. oil, is supplied by a pump 6 from a tank 7 and is heated by a resistor 8 controlled by a thermostat 9. The duct 5 is connected through a valve 10 either to a line 12 through which the cold liquid, e.g. water, is supplied or to a line 13 in communication with the atmosphere. The cold liquid is circulated through the duct 5 only at the end of the welding cycle. When the jaw is opened the line 13 is connected to the duct 5 so that air flushes the cold liquid out of the duct 5 and the jaw is rapidly re-heated by the liquid or steam in the duct 3. The duct 3 may be of circular cross-section, Fig. 1 (not shown), or may be provided with radial recesses (3a), Fig. 4 (not shown), to increase the inner surface area thereof to reduce the time taken to heat the jaw to its working temperature. In a further modification, Fig. 5 (not shown), the duct 3 is replaced by a number of ducts each of smaller diameter to give a greater inner surface area. If thin sheets are to be welded they are placed between the jaw and a resilient support, e.g. a silicone rubber block, Fig. 9 (not shown). To weld thicker sheets, they are positioned between two identical jaws, Fig. 10 (not shown). In another embodiment, Fig. 8, the hot liquid circulates through a passage 19 formed by two members 18, 23 welded at 24. A bore 25 forms the duct for the cooling liquid. The member 18 may be made of brass and the member 23 is made of a better heat conducting metal, e.g. copper. The jaw may be provided with a glasspolytetrafluoroethylene covering to prevent adhesion of the materials thereto. In a further embodiment, Fig. 11, to simultaneously weld and sever thermoplastic sheets, a lower jaw is formed of two members 18, 23 provided with a heating duct 19 and two cooling ducts 25 one on each side of a groove 26 in which a cutting blade 27 is disposed, the heel 27a of the blade being continuously heated. The welding surfaces 28 of the jaw are provided with a covering 29. The jaw is opposed by a member 30 comprising two silicone rubber blocks 32 opposite the surfaces 28 and a metal part 33 opposite the blade 27. |
