| 摘要 |
1434353 Cellular thermoplastic articles PROFILE EXPANDED PLASTICS Ltd 23 July 1973 [21 July 1972] 34307/72 Addition to 1326192 Heading B5A Cellular thermoplastic articles having a varying density throughout are formed by distributing heat-expandable beads in layers of different density in a mould by feeding them through a filler opening in the mould wall on to a deflector inside the mould to separate the flow of beads into separate streams and deflect the streams to different parts of the mould, while varying the average density of the beads fed to provide the desired density and then heating the beads to expand and fuse them together. At least some beads are pre-expanded. In the manufacture of a wing chair frame, Fig. 3, the lower extremities 13, 14 if the mould 10, 11 define the upper portion of the chair back and front portion of the chair seat respectively. Beads are fed through opening 15 on to deflector plate 16 which extends through a slot 17 in the mould wall and has a flange 18 bolted to the outside of mould part 11. Plate 16 may be deformed so as to give the desired distribution of heavy density beads, e.g. such that the ratio of the rates of flow of the beads in the two streams equals the ratio of the volumes of the mould parts defining the chair back and seat so that these are filled at the same rate. |
