APPARATUS FOR PULLING BAG-MAKING MATERIAL FOR FORM-FILL-SEAL PACKAGING MACHINE

摘要

A film-pulling apparatus for a packaging machine includes guide plates with arcuate inner surfaces. A cylindrically formed bag-making film material is pulled down inside these guide plates while being adsorbed to their inner surfaces by the negative pressure inside suction vacuum chambers flanking the path of the film material. A pair of pull-down belts is vertically stretched between pulleys adjacent to the path and over the suction vacuum chambers. The belts have many holes such that the negative pressure from the suction vacuum chambers is communicated to the film material through the pull-down belts as the pulleys rotate to pull down the film material. An auxiliary vacuum chamber is connected to the suction vacuum chamber through a normally closed valve such that the vacuum condition in the suction chamber can be quickly restored by opening this valve when an abnormal pressure condition in the suction vacuum chamber is detected. The axes of the pulleys are supported by axle bearings engaging with right-hand and left-hand screw parts of a turnbuckle such that the separation between the belts can be accurately adjusted by rotating the turnbuckle.