SVETSANORDNING FOR TUNNA FOREMAL

摘要

1516951 Dielectric heating SOC GENERALE POUR L'EMBALLAGE 18 Feb 1976 [19 Feb 1975] 06413/76 Heading H5H [Also in Division B5] Apparatus for welding together sheets, edges of receptacles, e.g. yoghurt pots and dentifrice tubes, comprises (a) a rotatable assembly carrying at least one pair of jaws 6, 7 for gripping objects to be welded, each jaw comprising an electrode connected to at least one circuit member 4, 5, and (b) an A.C. generator 1 each pole of which is connected to at least one circuit member 2, 3 fixed relative to the generator and positioned adjacent the path of travel of a respective circuit member 4, 5 of one of the electrodes so that, as the member 4 or 5 moves, the members 2, 3, 4, 5, when adjacent, form a circuit to transmit current from the generator to the electrodes. As shown in Fig. 1, the fixed plates 2, 3 are in the form of an arc of a circle and the plates 4, 5 are spaced at a small distance therefrom to effect capacitative coupling. A condenser 8 is formed when the jaws 6, 7 are closed with the articles to be welded therebetween, the circuit including the condenser 8 being tunable by an adjustable resistance 9. As the plates 4, 5 are driven with a rotating movement in direction f to sweep the surface of the plates 2, 3, during the time that the capacitative coupling lasts, the passage of high frequency current in the circuit effects welding of the articles. The capacity of the condenser is increased if the plates comprise a plurality of blades, e.g. if each movable plate comprises two blades straddling the fixed plate, Fig. 2a (not shown), or if each fixed plate comprises two blades straddling the movable plate, Fig. 2b (not shown). In Fig. 3, a plurality of welding stations P 1 , P 2 is arranged in a circle and each comprises blades 41, 4" and 5', 5" connected to jaws 10,11 between which are engaged two pieces 12, 13 of a polyethylene-paper laminate to be welded. The jaw 10 is mounted on a fixed support 14 and the jaw 11 is movable relative thereto. The welding stations are rotatable in a circle so that the blades 41, 411 and 51, 511 pass before fixed plates 2, 3 connected by a coaxial connection 15 to a generator 1 and of such a length that they cannot be simultaneously facing the plates of two successive stations. In Fig. 4, on the periphery of a cylindrical housing 16 are mounted the fixed plates each comprising two blades 2', 2" and 3', 3". Welding stations are mounted on a support 17 rotatable about a column 18 and each comprises a fixed jaw 10 and a jaw 11 pivotable about an axis 20 to a closed position, against the action of a spring 25, by a cam 26 acting on a roller 27 on a rod 24 articulated to a lever 23 on the jaw 11. The welding electrodes 21, 22 are directly connected to the blades 4, 5. (For figures see next page)