Application of zippers to film material

摘要

The apparatus applies a transverse zipper strip to a film (10) moving continuously in a direction (12). A continuous belt (18) is driven by sprocket wheels (16a, 16b) and carries upper seal bars (22a, 22b, 22c) which receive pre-cut lengths of zipper at station (3) The pre-cut lengths are attached to the film (10) by a lower seal bar (24) which moves towards the film (12) at position A when an upper seal bar carrying a zipper strip is located directly above the film. Sealing takes place as the upper and lower seal bars move at the same speed as the film (12) from position A to position B where the zipper is released from the upper seal bar (22c). The process then repeats for the next zipper strip length.