Tubular bag with shock absorber band tube for making such bag, and method for its production
First Claim
1. A tube for forming a tubular bag closed at at least one end by a generally transverse seam at a predetermined generally transverse locus along the length of the tube, said seam resulting in a rupture zone adjacent thereto which is susceptible to rupture when subjected to impact stress, said tube being formed of generally continuous orientable thermoplastic polymeric material, the film material of said tube including adjacent the predetermined locus of said rupture zone a shock-absorbing band of limited depth perpendicular to said predetermined locus which is separated from said locus by a region of unstretched film material and extends in width over a significant portion of the transverse dimension of the tube, said shock absorbing band comprising:
- a plurality of discrete stretched zones of film material stretched in a direction generally perpendicular to the locus and alternating one by one with a plurality of generally narrow stripes of substantially unstretched film material with the stripes extending lengthwise in substantially the same generally perpendicular direction,whereby impact stress forces applied to the tube material adjacent said rupture zone are transmitted away from said rupture zone and absorbed by said shock absorber band to thereby significantly improve the resistance of the tube to impact stress applied to said rupture zone.
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Accused Products
Abstract
Orientable thermoplastic polymeric film material is provided with at least one stretched zone in which the material has been stretched in a first direction and, adjacent to the opposite sides of the zone, unstretched zones in which the material is substantially unstretched. The material is of particular value for preventing rupture of bags containing the material, especially when the zones are adjacent a seam in a filled sack and/or in the gusset of a gusset bag.
136 Citations
29 Claims
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1. A tube for forming a tubular bag closed at at least one end by a generally transverse seam at a predetermined generally transverse locus along the length of the tube, said seam resulting in a rupture zone adjacent thereto which is susceptible to rupture when subjected to impact stress, said tube being formed of generally continuous orientable thermoplastic polymeric material, the film material of said tube including adjacent the predetermined locus of said rupture zone a shock-absorbing band of limited depth perpendicular to said predetermined locus which is separated from said locus by a region of unstretched film material and extends in width over a significant portion of the transverse dimension of the tube, said shock absorbing band comprising:
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a plurality of discrete stretched zones of film material stretched in a direction generally perpendicular to the locus and alternating one by one with a plurality of generally narrow stripes of substantially unstretched film material with the stripes extending lengthwise in substantially the same generally perpendicular direction, whereby impact stress forces applied to the tube material adjacent said rupture zone are transmitted away from said rupture zone and absorbed by said shock absorber band to thereby significantly improve the resistance of the tube to impact stress applied to said rupture zone. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A tube for bag-making formed of a sheet of continuous orientable thermoplastic polymeric film material, said sheet having two opposite side edges which are seamed together to form a longitudinal seam and having adjacent said longitudinal seam a rupture zone susceptible to undergoing rupture when subjected to impact stress, the film material of said tube including adjacent each said rupture zone a shock-absorbing band which is separated from said longitudinal seam by a region of unstretched film material and extends along a significant portion of the seam length, said shock absorbing band comprising:
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a plurality of discrete stretched zones of film material stretched in a direction generally perpendicular to the seam alternating one by one with a plurality of stripes of substantially unstretched film material with the length of said stripes extending in a direction generally perpendicular to the seam, whereby when the rupture zones are subjected to impact stress, the stress forces are transmitted away from said rupture zone and absorbed by said shock absorber band to thereby significantly improve the the resistance of the rupture zones to such stress.
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12. A tubular gusseted bag having at least one generally transverse seam defining an end thereof, being formed of generally continuous orientable thermoplastic polymeric film material, said bag comprising opposed generally rectangular front and back panels of film material united along side edges of such panels and having corresponding side margins of respective ones of said panels adjacent said side edges each tucked inwardly along a central fold line and held in such tucked position by said seam to create a gusset to give a generally rectangular shape in transverse cross-section to the bag when expanded, the gussetted bag being susceptible to rupture under impact stress at a junction of each said fold line and said seam, the tubular bag therefor being provided on the tucked side margins of each said gusset adjacent to each said rupture junction with a localized stress-relieving zone, each said stress-relieving zone comprising:
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at least one elongated zone of stretched film material formed by stretching the film material in a direction generally perpendicular to the end seam along at least one line intersecting the center fold line of at at least one of said gussets and extending on either side of the center fold line into the tucked side margins of the gusset, whereby impact stress applied to said at least one gusset is prevented from being concentrated at the rupture junctions by said stress-relieving zones to thereby significantly improve resistance of such rupture junctions to rupture under such stress. - View Dependent Claims (13, 14)
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15. In a bag formed from continuous orientable polymeric film material and having at least one generally transverse seam defining an end of the bag which seam is susceptible to rupture when stressed, the improvement comprising a pattern of discrete localized embossed indentations in the film material defining a generally band-shaped zone extending generally parallel to said seam in a location adjacent to but separated from the seam, the film material of said embossed indentations being stretched mainly in a direction perpendicular to the length of the seam, said indentations being arranged in a plurality of rows generally perpendicular to the seam length which are separated by ribbons of unstretched film material, whereby the resistance of the seam to rupture under stress is significantly increased.
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16. A tube formed of generally continuous orientable thermoplastic polymeric film material for forming a tubular gusseted bag closed at at least one end thereof by a generally transverse seam, each such seam being located at a predetermined generally transverse locus along the length of the tube, said gussetted bag comprising opposed generally rectangular front and back panels of film material united along side edges of such panels and having corresponding side margins of respective ones of said panels adjacent said side edges each tucked inwardly along a central fold line and held in such tucked position by said seam to create a gusset to give a generally rectangular shape in transverse cross-section to the bag when expanded, the gussetted gussetted bag being susceptible to rupture under impact stress at a junction of each said fold line and said seam, the improvement wherein the film material of the tube for said gussetted bag is provided at a locus which corresponds to the tucked side margins of each said gusset of the gussetted bag and is adjacent to each of the rupture junctions with a localized stress-relieving zone, each said stress-relieving zone comprising:
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at least one elongated zone of stretched film material formed by stretching the film material in said zone in a direction generally perpendicular to the predetermined generally transverse locus of the end seam along at least one line which intersects the center fold line of of at least one of said gussets of the gussetted bag and extends on either side of such center fold line generally parallel to said predetermined locus of said end seam, whereby impact stress applied to the gussets of the gussetted bag is prevented from being concentrated at the rupture junctions by said stress-relieving zones to thereby significantly improve the resistance of such rupture junctions to rupture under such stress. - View Dependent Claims (17, 18, 19)
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20. A tubular bag closed at at least one end by a generally transverse seam, said seam resulting in at least one rupture zone adjacent thereto which is susceptible to rupture when subjected to impact stress, said bag being formed of generally continuous orientable thermoplastic polymeric material, the film material of said bag including adjacent each such rupture zone a shock-absorbing band of limited depth perpendicular to said seam which is separated from said seam by a region of unstretched film material and extends generally parallel to said seam over a significant portion of the seam length, said shock absorbing band comprising:
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a plurality of discrete stretched zones of film material stretched in a direction generally perpendicular to the seam alternating one by one with a plurality of generally narrow stripes of substantially unstretched film material with the stripes extending lengthwise in substantially the same generally perpendicular direction, whereby impact stress forces applied to the bag material adjacent said rupture zone are transmitted away from said rupture zone and absorbed by said shock absorber band to thereby significantly improve the resistance of the bag to impact stress applied to said rupture zone. - View Dependent Claims (21)
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22. A tubular bag having a generally transverse seam at one end and and a generally longitudinal seam along at least one side thereof, said bag being formed of continuous orientable thermoplastic polymeric film material, said bag having adjacent said longitudinal seam a rupture zone susceptible to undergoing rupture when subjected to impact stress, the film material of said tube including adjacent said rupture zone a shock-absorbing band which is separated from said longitudinal seam by a region of unstretched film material and extends generally parallel to said longitudinal seam over a significant portion of the length of said longitudinal seam, said shock abosorbing band comprising:
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a plurality of discrete stretched zones of film material stretched in a direction generally perpendicular to the longitudinal seam alternating one by one with a plurality of stripes of substantially unstretched film material with the length of said stripes extending in a direction generally perpendicular to said longitudinal seam, whereby impact stress forces applied to said rupture zone are transmitted away from said rupture zone and absorbed by said shock absorber band to thereby significantly improve the resistance of the rupture zone to such stress.
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- 23. A method of manufacturing from generally continuous orientable polymeric film material a bag having a generally transverse seam at a predetermined location defining at least one end of the bag, which comprises before or after the seam is made, embossing the film material along a generally band-shaped zone adjacent to but separated from the location of the seam with a pattern of discrete localized indentations in which the film material is stretched mainly in a direction perpendicular to the length of the seam, said indentations being arranged in a plurality of rows generally perpendicular to the seam length which are separated by ribbons of unstretched film material.
- 26. In a method of manufacturing from generally continuous orientable thermoplastic polymeric film material a gussetted bag having opposed front and back faces, each such face having opposite side edges with the corresponding side edges of the faces being united and having opposite side margins adjacent such side edges, the corresponding side margins of the respective faces being tucked inwardly along a central fold line to form a gusset, said bag having across at least one end thereof a generally transverse seam which extends across the inwardly tucked side margins of the gusset to secure such inwardly tucked side margins in their inwardly tucked condition, the end seam intersecting with each central fold line to define at such intersection a point of susceptibility to rupture under impact stress, the improvement which comprises the step of embossing selective regions of said inwardly tucked side margins generally adjacent to each rupture point along at least one line which intersects the corresponding central fold line in generally perpendicular relation and extends into the tucked side margins on either side of such central fold line to form in the gusset a transverse zone of stretched film material adjacent each rupture point which zone is capable of relieving impact stress on that rupture point.
Specification