Abstract: A web of flat plastic bag stock formed with transverse perforations and heat seals is separated into individual bags, then individually formed in plural folds and the folded bags are stacked for packaging. To form as many as three folds, four rollers are used. The individual, separated bag is forced between the first and second rolls by a reciprocating first "blade" which contacts the middle of the bag. After being formed with the first fold, the bag is forced between the second and third rolls by a reciprocating second "blade". The twice-folded bag is then forced between the third and fourth rolls by a third reciprocating "blade" and, after the third fold, is conveyed away on belts to a stacking station where plural bags are deposited as a layer on a table. The layers may be packaged by hand or by suitable machinery.

Abstract: A web of flattened, tubular, heat-sealable bag material travels above and at the speed of a moving belt. Above the belt is a seal shaft which rotates a heated seal bar. The working edge of the seal bar may be adjusted inward and outward relative to its shaft. The edge causes a transverse seal to be made on the web at intervals. A rotary perforating knife is driven at the same speed as the seal shaft and, at a subsequent station, perforates the web proximate the seal. The linear speed of the edge of the seal bar is at the speed of the belt at the time of sealing contact (about 65.degree.). The speed of the seal shaft for the remaining 295.degree. is adjustable and thereby the distance between seals and perforations is adjustable.