| 摘要 |
The invention is embodied in bag-making apparatus wherein a tubular web of thermoplastic film is intermittently advanced, in bag-length increments. In the dwell between successive advances, there is a cycle of sealing, cut-off and stack accumulation, the accumulation being onto needles to form a stack. The needles comprise a single group, forming part of a single transfer mechanism, operative (a) to transfer to a conveyor each successive needled stack, into partially lapped relation with the previously transferred stack, (b) to disengage its needles from the transferred stack, and (c) to return the needles to normal needling position, for anchored accumulation of bags as they are formed for the next stack. The transfer operation, including return of the needles to needling position, occurs within the dwell time required for one bag-seal and cut-off operation, so that normal full-speed operation of bag-sealing and cut-off mechanism can proceed without interruption, even though the single set of stack-accumulative needles is, at stack-completion intervals, transiently involved in stack-transfer to the conveyor. |
