PACKAGE SENSING/FILM CONTROL SYSTEM FOR FILM WRAPPING MACHINE

摘要

PACKAGE SENSING/FILM CONTROL SYSTEM FOR FILM WRAPPING MACHINE A package sensing system provides length, width and height signals to a film control system which selects the width and length of stretch film to be used by a film wrapping machine to wrap the sensed package. Package width is sensed by spring biased swing arms which activate electrical switches upon deflection by an entering package. A wide package is indicated if both swing arms are deflected. The length and height of a package are sensed by a generally vertical downwardly extending lever arm which is pivotally mounted above the package entryway into the machine. A first electrical switch coupled to the lever arm generates a length signal upon initial contact by an entering package and a second electrical switch coupled to the lever arm generates a height signal depending upon the ultimate deflection of the lever arm by the package. Two film widths are provided with the narrower of the two being selected for packages which activate neither the width sensing system or the height sensing system and the wider of the two films being selected upon activation of either of those sensing systems. The length of the film drawn is determined by the length of a measured package with that length being incrementally increased if a high package is sensed.