| 摘要 |
An appts. for producing sealable plastic bags incorporates a filling tube (12) and forming collar, guiding the plastic sheet material (10) around the filling tube (12) to form it into a tube, bringing the lateral edges (16) together to form the two opening sides of the bag. As it does so, a male profile section (18) and female profile section (20) are continuously guided on two guide tubes (22), which are of rectangular cross section, each having an internal conduit (24) through which forced blasts of hot air may be directed. At predetermined intervals, hot air escapes through holes, (26,28) through the tubes (22) in timed blasts to impinge on the interlocked male and female profile sections (18,20). The guide tubes are otherwise insulated. The hot air, being directed at the engaging surfaces of the profiles, softens them to enable them to be fused into a tight seal. The sheet (10) is moved in incremental steps equal to the width of the bags being produced. At each step, hot air warms the male and female profile sections (18,20). Simultaneously vertical seal bars (30) compress the edges (16) to seal them to their respective profiles. Adjacent areas of the male and female sections (18,20) are also pre-warmed, and at the same time seal bars (32) clamp across the sheet material (10) to form a side seal (34) and cut the sheet into a bag. |
