Package wrapping method and machine

Abstract

An elevator-type package wrapping machine which determines as by premeasurement the length of packages fed at a first level thereto, comprises a film gripper for initially drawing a fixed length of stretch film horizontally from a supply roll to a fixed stop position in the machine. While the film is held by the film gripper, a package which has one edge thereof at a predetermined distance from the fixed stop position is elevated to a second level above the level of the gripper into the film such that the package draws a first addition to the length of film drawn by the gripper, according to the height of the package. A vertically-moving horizontal bar is moved into contact with the film remote from the fixed stop position to pull a second additional length of film from the film source in accordance with the measured package length, if required. A film cutter is provided for severing the film from its source while the film is stationary, following which, film side and rear underfolders fold the lateral edges of the film and the rear edge of the film extending from the film source under the package. The underfolders and horizontal bar are operated independent mechanisms, enabling separate timing of each. The package is then pushed essentially horizontally in an outfeed direction, at which time the gripper releases the film and allows the released portion to be underfolded beneath the package as it is pushed. The package is then passed over a heated belt to seal the overlapping edges of the film beneath the package.