An apparatus for high frequency welding, in particular for welding of inlays made of plastics

摘要

1436159 Seaming and finishing edges of non-metallic sheet material ZAVODY ELEKTROTEPELNYCH ZARAZENI (ZEZ) NARODNI PODNIK 29 Oct 1973 [1 Nov 1972] 50207/73 Heading B5K High frequency welding apparatus for producing a welded seam including a bead 4SP1/SP comprises a pair of welding electrodes 1, 2 and a frame member 6 juxtaposed to, but electrically insulated from, the electrodes 1, 2, the member 6 having a bead receiving recess 7 bounded on a side thereof by a wall 5 resiliently biased towards the recess 7. As shown, the wall 5 is in the form of a resilient plate having a lip 5SP1/SP causing a small restriction to the opening of the recess 7. The wall 7SP1/SP of the recess opposite to the plate 5 has a downwardly-turned end 7SP11/SP to form a further small restriction. To form a beaded seam, e.g. in a bag, case or motor car seat, a strip 4 having a bead 4SP1/SP is inserted between the margins of plastics sheets 3. The assembly is positioned with the bead 4SP1/SP extending as far as it will go into the recess 7 with 10-25% of the diameter of the bead protruding therefrom and welding is effected. The cross-section of the bead may be circular, as shown, or elliptical.