| 摘要 |
800,820. Heating plastics by resistors. GRUBER, H. Sent. 27, 1955 [Sept. 28, 1954; Oct. 6, 1954], No. 27423/55. Class 39(3) [Also in Groups VIII and XXII] In welding together two pieces of plastic especially rubber or thermoplastic sheets 7, 8 by placing a metal resistance 6 between the meeting surfaces and pressing them together so that on passage of current the surfaces fuse together and embed the resistance 6, the latter is formed at the parts adjacent the edges of the plastic sheets with terminal pieces 12 of enlarged cross section, on to which cool air is blown to prevent over-heating of the resistance exterior to the plastic sheets. The resistance may be one or more wires, a metal network or a metal band with numerous triangular apertures. The resistance may be iron coated with a material e.g. brass or zinc having a better affinity for the plastic (P.V.C.) than has the metal, and may be used in making bags, mats, flexible tubes, shoes or zip-fasteners. |
