| 摘要 |
Apparatuses for heat-sealing thermoplastic materials include one or more cooperating sealing jaws which display mutually facing work surfaces with means for heating the thermoplastic material. When heating means in the form of a wire or a strip of electrically heatable resistor material are employed, extreme demands are placed on the anchorage of this to the sealing jaw, since elongation changes (linear expansion and contraction) and mechanical action risk bringing the strip out of its intended position while the sealing jaw is in operation. An apparatus for heat-sealing thermoplastic materials which obviates these drawbacks includes a sealing jaw with grooves in which a thermal strip is mechanically anchored in that the flange portions of the jaw projecting on either side of the groove are compressed towards one another and the interjacent thermal strip. The sealing jaw is manufactured from aluminium which has been surface anodized to create an electrically insulating layer between the body of the jaw and the thermal strip. <IMAGE> |
