PACKAGING MACHINE AND METHOD

摘要

A jam prevention device comprises a light beam source that emits a light beam and is located on a main frame structure of a packaging machine in the machine's sealing section. During operation, the light beam is reflected off tworeflective surfaces located on a moveable support operably connected to a prime mover. The reflected beam is received by a receiver located opposite the source.A clamping sub-assembly includes a seal bar and a reciprocatable seal pad housing. The housing is spring-mounted on the clamping sub-assembly and substantially surrounds the seal bar. The reflective devices are mounted on the housing. The prime mover moves the clamping sub-assembly towards a heater bar sub-assembly. The housing defines two cavities for receiving the reflective devices. The movement of the clamping sub-assembly brings a loaded bag into contact with the heater bar sub-assembly for the purpose of effectuating a seal of the bag. The pressure applied by the clamping sub-assembly during the meeting of the clampingsub-assembly and the heater bar sub-assembly causes the housing to move during the sealing process thereby moving the reflective devices into the cavities and disrupting the light beam. A photo-sensor is provided for detecting the reflection of the light beam during the sealing process as just described. Control structure either allows or disallows the sealing process to continue based upon detection of the light beam.