| 摘要 |
An arrangement is described for registering stretchable lids with mating product-filled troughs of a heat-sealed product container prior to the heat-sealing operation. The troughs are preformed at first intervals on a first strip, which is successively indexed through the first interval into the heat-sealing station. The lids are defined between regularly spaced detectable markings on a second strip, which is moved into the heat-sealing station simultaneously with the first strip. The markings on the second strip are normally spaced by a second interval slightly smaller than the first interval. At the end of each indexing movement, a marking on the second strip comes into alignment with a photocell to generate a signal. A stretching station upstream of the photocell responds to the signal to grip a lid-defining section of the second strip between spaced clamps, and to thereafter impart a permanent elongation to the gripped lid by an amount sufficient so that the elongated section later registers with a trough at the heat-sealing station.
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