| 摘要 |
1,130,615. Dielectric heating electrodes. FORD MOTOR CO. Ltd. 24 Aug., 1966 [20 Oct., 1965], No. 37882/66. Heading H5H. [Also in Division B5] A die for bonding together selected areas of sheets 21, 23, 25, 27 of dielectric material comprises an electrode assembly which includes a plurality of electrodes 43, 45, 47 electrically connected in parallel to a source 73 of R.F. current, the electrodes 43, 45, 47 having working surfaces 43-1, 45-1, 47-1 to press the selected areas against another electrode 31 connected to the source 73 to bond the areas by dielectric heating, the electrical conductivity of the electrodes 43, 45, 47 differing from one electrode to another. A door panel 10, Fig. 3, for an automobile comprises a press wood board 21, a pad 23 comprising rayon fibres and a thermoplastic resin, a thermoplastic vinyl sheet 25, e.g. polyvinyl chloride, and a second thermoplastic vinyl sheet 27. The electrodes 43, 45, 47 are electrically connected to a lower electrode 33 which is connected to the source 73. The electrodes 31, 33 are made of aluminium, the electrode 43 of copper, the electrode 45 of brass, stainless steel or another alloy and the electrode 47 of copper or an alloy. In one embodiment, the electrodes 43, 47 have the same electrical resistivity and the electrode 45 has a greater resistivity. In a second embodiment, the electrode 47 has a greater resistivity than the electrode 43 but less than the electrode 45. In operation, the sheets 21, 23, 25, 27 are placed on the electrodes 43, 45, 47 and polyurethane spacer pads 49, 51, 53, 55 and held in position by clamps 39, 41. Stays 37 are disengaged and the electrode 31 is closed to overlie the sheets. The electrodes 31, 33 are forced together by pressure applied pneumatically or hydraulically and then R.F. is supplied to effect bonding. |
