| 摘要 |
1,010,324. Laminates; sealing non-metallic sheet material. INTERNATIONAL ULTRASONICS Inc. Dec. 11, 1961 [Jan. 17, 1961], No. 44279/61. Headings B5K and B5N. [Also in Division H4] Layers of material, including a plastics layer, are welded together under pressure from a vibrating nub driven by ultrasonic means and the penetration of which is limited. The invention has particular application to welding molecularly oriented polyesters and high density polythene but appears to be generally applicable to plastics materials having a coefficient of friction greater than 0À04. The welding of high-density polethylenes to low-density polyethylenes is mentioned as also is the welding of films coated with, for example, photographic emulsion or metal, and the forming of laminates of plastics materials and paper. Continuous seaming or discontinuous stitch welds may be effected by the apparatus and the invention may be combined with a heat sealing process or may be performed in the presence of cooling media, e.g. under water. In a form of apparatus in which the work is held stationary the welding unit is mounted to be traversed manually or automatically and consists of a nub 6 mounted on members 12, 17 connected to a vibrational driving unit that may be a piezoelectric sandwich transducer driven to vibrate at frequencies within the range of 20 to 50 kilocycles. Other apparatus, Fig. 6 (not shown), has arrangements for moving the work beneath the welding tool. |
