RING WRAPPING APPARATUS INCLUDING METERED PRE-STRETCH FILM DELIVERY ASSEMBLY

摘要

The present invention provides a method and apparatus for dispensing a predetermined fixed amount of pre-stretched packaging material based upon load girth. A non-rotating ring carries a belt driven by a motor. A packaging material dispenser is mounted on a rotating ring, and the rotating ring may include a pulley that connects to the band, such that the rotating ring is driven by the drive belt. Based upon the girth of the load to be wrapped, an amount of pre-stretched packaging material to be dispensed for each revolution made by the rotating ring is determined. Good wrapping performance in terms of load containment (wrap force) and optimum packaging material use is obtained by dispensing a length of pre-stretched packaging material that is between approximately 90% and approximately 120% of load girth. Once the amount of packaging material to be dispensed per revolution is determined, a ratio of rotating ring drive to final pre-stretch surface speed (i.e., number of pre-stretch roller revolution/ rotating ring rotation) can be set and mechanically controlled. Thus, for each revolution of the rotating ring and dispenser, a predetermined fixed amount of packaging material is dispensed and wrapped around the load. In an alternative embodiment, the ratio is electronically controlled.