Method and apparatus for manufacturing bags of a continuous web of a thermoplastic synthetic sheet material
OwnerLeonard Van der Meuleninventor
Life of this patent
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Abstract
A method and apparatus for making bags from a thin thermoplastic material supplied as either a flat tube or a double-folded web to an advancing supporting path such as the common opposite flights of two sets of endless conveyors, thereby applying the loop-system principle, the supporting conveyors clamping the material at spaced intervals with two sets of clamping beams, lying close to each other, a separate set of cooperating sealing beams cooperating with the thermoplastic material for making the seals within the space between both sets of clamping beams.
Claims42
A method for the continuous manufacture of bags from a tubular web of synthetic sheet material comprising continuously supply said web to a bag producing zone at a first rate, clamping said web at regular intervals along its length at a clamping zone on said web at a point within said bag producing zone, said web being clamped between first and second pairs of clamping bars travelling along a pair of first paths juxtaposed on opposite sides of said web at a second rate, the relationship between said first rate and said second rate being such that tension in said web is avoided between said pairs of clamping bars, maintaining said web clamped between said pairs of clamping bars as said pairs of clamping bars travel along clamping path portions of said first paths parallel to said web, said clamping path portions having a first predetermined length, perforating said web at a first location on said web proximate to said clamping zone, and heat sealing said web at a second location on said web proximate to said clamping zone by contacting said web with heat sealing means travelling along a heat sealing path portion of a second path parallel to said web, said heat sealing path portion of said second path having a second predetermined length, said second predetermined length being less than said first predetermined length, so that said heat sealing path portion of said second path is contained entirely within and terminates before said clamping path portions of said first paths.
A method for the continuous manufacture of bags from a tubular web of synthetic sheet material comprising continuously supplying said web to a bag producing zone, clamping said web at regular intervals along its length at a clamping zone on said web at a point within said bag producing zone, said web being clamped between first and second pairs of clamping bars travelling along a pair of first paths juxtaposed on opposite sides of said web, maintaining said web clamped between said pairs of clamping bars as said pairs of clamping bars travel along clamping path portions of said first paths parallel to said web, said clamping path portions having a first predetermined length, perforating said web at a first location on said web proximate to said clamping zone, and heat sealing said web at a second location on said web in said clamping zone between said first and second pairs of clamping bars by contacting said web with heat sealing means travelling along a heat sealing path portion of said path parallel to said web, said heat sealing path portion of said second path having a second predetermined length, said second predetermined length being less than said first predetermined length, so that said heat sealing path portion of said second path is contained entirely within and terminates before said clamping path portions of said first paths.
Apparatus for continuously manufacturing bags from a tubular web of synthetic sheet material comprising;
- means for continuously feeding said web of synthetic sheet material to a bag producing zone at a feed velocity;
- clamping means comprising a plurality of first and second pairs of clamping bars adapted to travel in first and second endless circuits juxtaposed on opposite sides of said web, said first and second endless circuits each including a first path portion parallel to said web so that when said first and second pairs of clamping bars travel in said first path portions said web is clamped between said clamping bars at a first web location throughout the length of said first path portions, said first and second endless circuits comprising endless bands of chains and including a plurality of guide rollers for driving said endless bands of chains, said plurality of guide rollers including a first guide roller for each of said first and second endless circuits, said first guide rollers being juxtaposed on opposite sides of said web at the start of said bag producing zone,
- perforating means for transversely perforating said web at a point proximate to said first web location;
- and
- heat sealing means comprising a plurality of heat sealing bars travelling in a third endless circuit including a second path portion parallel to said web, so that said web is heat sealed as said heat sealing bars contact said web throughout the length of said second path portion, said second path portion being shorter than said first path portions so that said second path portion is contained entirely within and terminates before said first path portions.
Apparatus for continuously manufacturing bags from a tubular web of synthetic sheet material comprising;
- means for continuously feeding said web of synthetic sheet material to a bag producing zone at a feed velocity;
- clamping means comprising a plurality of first and second pairs of clamping bars adapted to travel in first and second endless circuits juxtaposed on opposite sides of said web at a predetermined velocity, said first and second endless circuits each including a first path portion parallel to said web so that when said first and second pairs of clamping bars travel in said first path portions said web is clamped between said clamping bars at a first web location throughout the length of said first path portions, said means for continuously feeding said web including control means for accurately controlling the feed velocity of said web so that the feed velocity of said web can be adjusted to be at least equal to said predetermined velocity so that tension in said web can be avoided between said pairs of clamping bars;
- perforating means for transversely perforating said web at a point proximate to said first web location;
- and
- heat sealing means comprising a plurality of heat sealing bars travelling in a third endless circuit including a second path portion parallel to said web, so that said web is heat sealed as said heat sealing bars contact said web throughout the length of said second path portion, said second path portion being shorter than said first path portions so that said second path portion is contained entirely within and terminates before said first path portions.
Dependencies are inferred from the claim text.