| 摘要 |
PCT No. PCT/SE96/01606 Sec. 371 Date May 5, 1998 Sec. 102(e) Date May 5, 1998 PCT Filed Jun. 12, 1996 PCT Pub. No. WO97/23339 PCT Pub. Date Jul. 3, 1997In the manufacture of packaging containers, for example blown plastic bottles, a circular material blank is, in certain cases, fixedly welded to the end of a sleeve-shaped casing portion. It is advantageous from amongst other energy viewpoint if the welding can take place using ultrasound, but in this instance it has been proved that the central region to the circular blank absorbs ultrasonic energy to such an extent that it is deformed or breaks. A method of using ultrasound to fixedly weld a circular material blank without such drawbacks occurring is proposed according to the present invention in that the oscillations caused by the ultrasound are reduced by a mechanical stabilization of the central region of the circular blank, which is put into effect with the aid of a vacuum and a relief pattern provided in the central region of the circular blank. An apparatus for employing ultrasound to fixedly weld a circular material blank in place displays a counter abutment with a work surface for fixedly retaining the circular material blank, the work surface forming a part of a vacuum chamber, and support means for the central region of the circular blank during the welding cycle. |
