| 摘要 |
A packaging machine and method for simultaneously loading, sealing and severing bags. A first stepper motor, having an output, is coupled to a nip roll assembly. After a bag is loaded, a sealing mechanism is actuated to seal the loaded bag or bags. A sensor monitors movement in a pressure bar and ter- minates the sealing cycle if a jam is detected before the pressure bar engag es a seal bar having a heater for sealing the bag. The stepper motor is used to retract bags and sever a leadmost bag that is clamped between the seal bar b y the pressure bar. A second stepper motor withdraws the web from a supply at a controlled rate to maintain tension in the web between the first and secon d stepper motors. A dancer roll assembly includes an orientation sensor for controlling the second stepper motor to speed up, slow down or stop.
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