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US 4,524,460 AGranted
Valved sack
AssigneeWindmoller & Holscher
InventorsKarl-Heinz Twiehoff, Reinhard Nowag
Life of this patent
Estimating the term…
Abstract
A sack is constructed from a thermoplastic film of which the side portions are brought into partial overlapping relationship to define a tube section and top and bottom weld seams are applied transversely. A longitudinal weld seam applied within the confines of the region of overlap terminates at a spacing from the top weld seam to define a filling valve passage. The region of overlap contains a longitudinal inner strip of reduced thickness made in one piece with the walls of the sack.
Claims15
A valved sack comprising:
- a web of thermoplastic film,
- a first marginal zone defined by the web including a marginal strip, said marginal strip having a thickness less than the thickness of the remainder of said web,
- a second marginal zone defined by the web, said first marginal zone being laterally opposed to said second marginal zone,
- a tube section formed by said second marginal zone overlapping said first marginal zone,
- a top weld seam,
- a bottom weld seam, said top weld seam and said bottom weld seam extending transversely across said tube section to form said valved sack,
- a longitudinal weld seam joining said first marginal zone and said second marginal zone, one end of the longitudinal weld seam terminating spaced from said top weld seam, and
- a valve passage defined between the top weld seam and the end of the longitudinal weld seam spaced from the top weld seam, said valve passage being bounded by said second marginal zone and said marginal strip, said marginal strip bounding said valve passage being of reduced thickness for resiliently sealing said sack after said sack is filled through said filling valve passage.
5 more elements
A valved sack comprising
- a tube section including a longitudinally extending strip of reduced wall thickness,
- a foldline defined by said strip, said strip being folded onto itself along said foldline,
- a first marginal zone defined by said tube section including said strip,
- a second marginal zone defined by said tube section including a side fold, said second marginal zone overlapping said first marginal zone,
- a top weld seam,
- a bottom weld seam, said top weld seam and said bottom weld seam extending transversely across said tube section,
- a longitudinal weld seam terminating at a distance from said top weld seam, said longitudinal weld seam being parallel to and spaced between the foldline of said strip and said side fold, and
- a valve passage, the width of said valve passage being defined by the separation between said top weld seam and said longitudinal weld seam, and the foldline of said strip being cut open in said valve passage.
5 more elements
Dependencies are inferred from the claim text.