| 摘要 |
Apparatus for heat sealing together two layers of thermoplastics strap (26, 28), comprising one or more thin, flat, electrical heating elements (16) supported under tension by use of a tensioning element (22) and means for moving said supporting means so that in use the heating element moves between the two strap layers (26, 28) in the longitudinal direction of the strap. The heating element is moved forward and then back, being supplied with heating current only during the reverse stroke, during which a fusing pressure is applied to the strap layers by means of resilient pads (30, 32). The tensioning element (22) may be a U-shaped bend at one end of the heating element. Current may be supplied by contacts running along rails to avoid flying leads. Pressure plates (90, 92) squeeze the strap components together above and below the heating element(s) (16, 16A). In addition a heated cutter (114) is provided to sever one of the strap components. |
