Impulse sealing apparatus

A system for heat sealing and severing thermoplastic films comprising a pair of elongated horizontal jaws, each said jaw in a "U"-shaped configuration mounted for movement toward and away from each other, each said jaw including a flexible cloth covering its open face, said cloth yieldable and heat resistant, said jaws adapted to hold at least two layers of thermoplastic film therebetween gripped at the two interfaces of the "U" of said jaws, one jaw including a resilient member therein mounted along the length thereof for movement towards and away from the other jaw, the other jaw including a heatable bar having a longitudinally extending projecting sharp edge and a separate longitudinally extending coolable bar mounted therein, both said bars mounted on a common support, said flexible cloth adapted to yield to said sharp projecting edge without being severed, and means for vertically moving said common support for alternately aligning said sharp edge and said coolable bar with said resilient member.