Stretch wrapping apparatus and method

Abstract

A stretch wrapping apparatus is adapted for use with an automated palletizing machine to securely stabilize loads prepared by the palletizing machine. The stretch wrapping machine works with a rotatable turntable on which the palletized load is placed. A stretch wrapping head feeds pre-stretched wrapping film toward the rotating load and air jets blow the tail of the film onto the load. Relative rotational movement is created between the wrapping head and the load and the free end of the film is unsupported by any mechanical structure and is directed toward the load only with air from the jets. The film attaches to an outer surface the load and the wrapping head moves vertically so that the load is helically wrapped. Film is dispensed at a rate to provide payout of film that is consistent with the demand as each load corner transitions through its relative distance change from the dispensing point based on calculations intervals. A sensor detects changes in the optical character of the film—defects—to determine an out of bounds condition such as a film break. A film cutter arm assembly uses a hot wire and press rolls to cut the film when the load is wrapped.