| 摘要 |
An in-line machine for attaching elongated, flexible closure tie elements to the individual bag portions of a laterally folded plastic film web being continuously discharged from a bag forming station, and being forcibly captured by a winder mechanism, engages and drives the moving web toward the winder mechanism by means of mutually spaced inlet, central and outlet drive rollers. During operation of the machine, first and second slack portions of the film web are respectively positioned between the inlet and central rollers, and between the central and outlet rollers. These slack portions are held in vertically looped configurations by a downwardly directed, yielding vacuum force applied thereto. The inlet and outlet rollers are driven at identical speeds corresponding to the constant linear film web output speed from the bag forming station. The central drive roller is alternately started and stopped to sequentially cause a portion of each bag to be momentarily stopped thereon, at which time the machine attaches a tie element to the stopped bag portion. During stoppage of each sequential bag portion, continued rotation of the inlet and outlet rollers lengthens the first film loop and shortens the second film loop. When the central drive roller is restarted it operates to equalize the film loop lengths. In this manner, each bag may be momentarily stopped, for tie element attachment purposes, without altering the constant output and input speeds of the bag forming station and winder mechanisms, and without imposing undesirably high longitudinal tension force on the plastic film web.
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