A packaging machine and method for simultaneously loading, sealing and severing bags forming part of at least two independent chains of bags. Two juxtaposed nip roll assemblies including axially aligned feed roll portions can be independently actuated in order to selectively feed one or two webs. A drive...http://www.google.es/patents/US4899520?utm_source=gb-gplus-sharePatente US4899520 - Packaging apparatus and method
