(57) In a stretch film wrapping machine an improved control system provides for automatic
or manual selection of one of at least two differing width film rolls and provides
individualized wrapping parameters dependent upon the film width selected. Automatic
film selection is performed in response to signals identifying the height, width and
length of a package to be wrapped which characteristics are sensed or measured by
a package sensing system (222, 226, 228, 230, 232, 234, 236, 242, 244). Both automatic
and manual film selection includes timing controls (600) for synchronizing film gripping
and clamping apparatus with underfolding apparatus dependent upon the film selected
to provide improved control over the tensioning of film wrapped about individual packages.
The improved control system monitors the operation of the wrapping machine to detect
jam conditions and stops the machine for such jam conditions. The system also provides
for limited reverse operation of the film wrapping machine for jam removal. The rear
film underfolder and package pusher are mounted to be moved away from the machine
to further facilitate jam removal. The improved control system monitors a film tensioning
roller via an electrical switch to verify film draw into the machine. If no film is
drawn indicating a film source problem, the machine is stopped.
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