초록 ▼

Method of and apparatus for producing plastic bags having separable plastic fasteners. A strip of bag making material is advanced step-by-step by bag width sections into a tear sealing station where the strip is retained for a dwell interval. In the station, the separable fastener means of the bag m

Method of and apparatus for producing plastic bags having separable plastic fasteners. A strip of bag making material is advanced step-by-step by bag width sections into a tear sealing station where the strip is retained for a dwell interval. In the station, the separable fastener means of the bag material is subjected to ultrasonic tear sealing as by means of a sonotrode along a bag edge defining line extending across the strip. Also in such station, the thinner bag body material is heat tear sealed along the bag side edge defining line as by means of a heat bar coordinated in operation with the ultrasonic sealing. The sonotrode has a profile comprising a tear line edge and material controlling and sealing rib means spaced from the tear line sealing edge.

대표청구항 ▼

In a method of producing plastic bags having separable plastic fasteners on one end, and in which the bags are formed by severing bag sections from a continuous integral film and fastener strip in which thin bag body material has in a relatively narrow area extending coextensively along a longitudin

In a method of producing plastic bags having separable plastic fasteners on one end, and in which the bags are formed by severing bag sections from a continuous integral film and fastener strip in which thin bag body material has in a relatively narrow area extending coextensively along a longitudinal edge separable fastener means of substantially greater unit mass modulus than the bag body material, and the body material and the fastener means thereby requiring different tear sealing techniques to effect separation of said strip into bag sections: advancing said strip step-by-step by bag width sections into a tear sealing station; retaining said strip for a short dwell interval in said station as each section is advanced into said station; subjecting said relatively narrow separable fastener means area in said station during said dwell interval to ultrasonic tear sealing including pressing thereacross and into the fastener means area a first elongate tear sealing edge means along a bag edge defining line which extends across said strip; and subjecting said bag body material in said station during each said dwell to heat tear sealing along said bag side edge defining line including pressing a second elongate tear sealing edge means longitudinally aligned with but separated at its adjacent end from said first edge means and coordinated in operation with said ultrasonic sealing first edge means. An apparatus for producing plastic bags having separable plastic fasteners on one of their ends, and in which the bags are formed by severing bag sections from a continuous integral film and fastener strip in which thin bag body material has in a relatively narrow area extending coextensively along a longitudinal edge separable fastener means of substantially greater unit mass modulus than the bag body material, and the body material and the fastener means thereby requiring different tear sealing techniques in order to effect separation of said strip into bag sections: a tear sealing station and means for advancing said strip step-by-step by bag width sections into such station wherein said strip is retained for a short dwell interval as each section is advanced into said station including a first elongate tear sealing edge; means in said station operable during each dwell interval and adapted for subjecting said relatively narrow separable fastener means area to ultrasonic heating and tear sealing pressure by said first edge aligned with a bag side edge defining line extending across said strip; and means in said station including a second elongate tear sealing edge longitudinally aligned with but separated at its adjacent end from said first edge an operable during each said dwell interval for subjecting said bag body material to heat tear sealing along said bag side edge defining line and coordinated in operation with said ultrasonic sealing means first edge.