| 摘要 |
A bubble guide unit according to the present invention comprises two concentric frames (10,11), at least one (11) of which rotates relative to the other (10), through which the film bubble passes. At least four bubble guiding rods (12,13,14,15) are arranged symmetrically to each other, and pivotally engage one frame (10) at one end (16a,16b,16c,16d) and to freely engage the other frame (11) near its other end (17a,17b,17c,17d). Freely engage here means that the other end of each rod is free to pivot to some extent as well as to move in the direction of its length beyond the pivoting point and back. This is most easily accomplished by a pivoting ring through which the rod passes or, less elegantly, by a fixed ring having an aperture larger than the rod diameter. <IMAGE> |
