Vertical form, fill and seal machine, components and method for making reclosable bags

摘要

A vertical form, fill and seal machine, components and method is disclosed which makes reclosable bags having a safety seal exterior to a reclosable seal and also produces durable, substantially air-tight bags at high speed and provides for the production of different size bags and different amounts of product in the bags. The disclosed machine includes a drive and pinch roll pair for pulling plastic film off of a plastic film supply roll, a pair of film pull belts biased against the plastic film wrapped around the fill tube and driven to pull the plastic film down along the side of the fill tube, and a pair of drive rollers for pulling the zipper strip through the machine. The production of different size bags is facilitated by having the plastic film drive roll, endless film pull belts, and zipper strip drive rollers all driven by a common drive source which is operated in bag length increments. Also, to accommodate the production of different size bags, a vertically adjustable ejector paddlewheel is located at the base of the machine. Further, the vertical form, fill and seal machine, components and method of the present invention insures reliable seals along the edges of each product-filled bag by having the zipper drive rollers elongate or stretch the bag material prior to cross-sealing the bag material. Also, the ejector paddlewheel serves to support the base of the bag in a manner which reduces wrinkles in the bag material along the upper edge during cross-sealing.