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(11) | EP 0 215 163 A1 |
(12) | EUROPEAN PATENT APPLICATION |
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(54) | Methods for preparing flat-bottom thermoplastic sack and systems therefor |
(57) A method and system for preparing flat bottom thermoplastic sacks comprising process
steps and means for forming a tube of thermoplastic film, collapsing said tube while
forming two oppositely disposed gussets therein, simultaneously or spatially sequentially
opening a gusset fold on each side of said collapsed tube to their full, lay-flat
extent; simultaneously or spatially sequentially forming in each of the four gusset
folds, a diagonal sealed seam (20) over the portions of the tube width corresponding
to the gussets along lines diagonal to the length of the tube so that the ends of
the sealed seams of adjacent gusset folds are at least closely spaced or in contact
so as to form an angle of at least approximately 90°, returning said gusset folds
to their original position so that their seal-pairs are superimposed, forming a transverse
sealed seam (24) across the tube along a line which includes the inboard ends of the
diagonal seams and forming preweakened transverse lines closely adjacent to said transverse
sealed seam or forming a severing line along this line; removing the four double triangular
regions (34) bounded by the diagonal seams, the transverse seam and the side edges
of the tube; and collecting the resulting structures either while still interconnected
or by stacking the severed sacks. The final structure can have handles (38) or it
can be handleless. |
(a) forming a tube of a thermoplastic film;
(b) collapsing said tube while simultaneously forming therein two, oppositely disposed, parallel gussets;
(c) opening, simultaneously or spatially sequentially, a gusset fold on each side of said collapsed tube, to their full lay-flat extent;
(d) simultaneously or spatially sequentially forming in each of the four gusset folds, a diagonal sealed seam over the portions of the tube width corresponding to the gussets along lines diagonal to the length of the tube so that the ends of the sealed seams of adjacent gusset folds are at least closely spaced or in contact so as to form an angle therebetween of at least approximately 90%;
(e) returning said gusset folds to their original position so that their seal-pairs are superimposed;
(f) forming a transverse seal and severing seam across and through said collapsed tube along a line which includes the inboard ends of said pairs of diagonal seams;
(g) collecting a plurality of the resulting structures in a stack;
(h) removing from each structure the four folded triangles of film located between the diagonal sealed seams and the transverse sealing and severing seams to complete the bottom of the sack; and
(i) forming a pair of handles and sack mouth opening at the opposite end of said sack bottom. For a pack of such bags a tab member is an integral extension of the bag mouth opening and each tab member has a pre-weakened region, such as perforations therein, so that when all tabs are fastened together, individual bags may be detached from the tab structure.
(a) forming a tube of thermoplastic film;
(b) collapsing said tube while simultaneously forming therein two oppositely disposed, parallel, gussets;
(c) opening simultaneously or spatially sequentially, a gusset fold on each side of said collapsed tube to their full lay-flat extent;
(d) simultaneously or spatially sequentially forming in each of the four gusset folds, a diagonal sealed-seam over the portions of the tube width corresponding to the gussets along lines diagonal to the length of the tube so that the ends of the sealed seams of adjacent gusset folds are at least closely spaced or in contact so as to form an angle of at least approximately 90%;
(e) returning said gusset folds to their original position so that their seal-pairs are superimposed;
(f) forming a transverse sealed seam across said tube along a line which includes the inboard ends of said pairs of diagonal seams and simultaneously forming a pre-weakened transverse line closely adjacent and parallel to said tranverse sealed seam;
(g) removing the four double film triangular regions bounded by said diagonal seams, said transverse seams and the side edges of said tube; and
(h) collecting the resulting structures while still interconnected at said pre-weakened transverse lines.
(a) forming a tube of thermoplastic film;
(b) collapsing said tube while simultaneously forming therein, two oppositely disposed, parallel, gussets;
(c) opening, simultaneously or spatially sequentially, a gusset fold on each side of said collapsed tube to their full, lay-flat extent;
(d) simultaneously or spatially sequentially forming in each of the four gusset folds, a diagonal sealed seam over the portions of the tube width corresponding to the gussets along lines diagonal to the length of the tube so that the ends of the sealed seams of adjacent gusset folds are at least closely spaced or in contact so as to form an angle therebetween of at least approximately 90%;
(e) returning said gusset folds to their original position so that their seal-pairs are superimposed;
(f) forming a transverse sealed seam across said tube along a line which includes the inboard ends of said pairs of diagonal seams and simultaneously severing said tube along a line parallel to said transverse sealed seam; and
(g) removing the four double film triangular regions bounded by said diagonal seams, said transverse sever line and the side edges of said period.
Figure 1 is a plan view, in schematic form, illustrating a system and process sequence of one form of the present invention.
Figure 2 is a plan view of another form of the process and system of the present invention.
(a) forming a tube of thermoplastic film;
(b) collapsing said tube while simultaneously forming therein two oppositely disposed, parallel gussets;
(c) opening, simultaneously or spatially sequentially, a gusset fold on each side of said collapsed tube to their full lay-flat extent;
(d) simultaneously or spatially sequentially forming in each of the four gusset folds, a diagonal sealed seam over the portions of the tube width corresponding to the gussets along lines diagonal to the length of the tube so that the ends of the sealed seams of adjacent gusset folds are at least closely spaced or in contact so as to form an angle of at least approximately 90°;
(e) returning said gusset folds to their original position so that their seal-pairs are superimposed;
(f) forming a transverse sealed seam across said tube along a line which includes the inboard ends of said pairs of diagonal seams and simultaneously forming a pre-weakened transverse line closely adjacent and parallel to said transverse sealing seams;
(g) removing the four double film triangular regions bounded by said diagonal seams, said transverse seam and the side edges of said tube; and
(h) collecting the resulting structures while still interconnected at said pre-weakened transverse lines.
(a) forming a tube of thermoplastic film;
(b) collapsing said tube while simultaneously forming therein two oppositely disposed, parallel gussets;
(c) opening, simultaneously or spatially sequentially, a gusset fold on each side of said collapsed tube to their full lay-flat extent;
(d) simultaneously or spatially sequentially forming in each of the four gusset folds, a diagonal sealed seam over the portions of the tube width corresponding to the gussets along lines diagonal to the length of the tube so that the ends of the sealed seams of adjacent gusset folds are at least closely spaced or in contact so as to form an angle of at least approximately 90°;
(e) returning said gusset folds to their original position so that their seal-pairs are superimposed;
(f) forming a transverse sealing and severing seam across and through said collapsed tube along a line which includes the inboard ends of said pairs of diagonal seams;
(g) collecting the resulting structures in a stack;
(h) removing the four folded triangles of film between the diagonal sealed seams and the transverse sealing and severing seam to complete the bottom of the sack; and
(i) forming a handle and sack mouth opening at the opposite end of said sack bottom.
(a) forming a tube of thermoplastic film;
(b) collapsing said tube while simultaneously forming therein two oppositely disposed, parallel, gussets;
(c) opening, simultaneously or spatially sequentially, a gusset fold on each side of said collapsed tube to their full lay-flat extent;
(d) simultaneously or spatially sequentially forming in each of the four gusset folds, a diagonal sealed seam over the portions of the tube width corresponding to the gussets along lines diagonal to the length of the tube so that the ends of the sealed seams of adjacent gusset folds are at least closely spaced or contact so as to form an angle of at least 90°;
(e) returning said gusset folds to their original position so that their seal-pairs are superimposed;
(f) forming a transverse sealed seam across said tube along a line which includes the inboard ends of said pairs of diagonal seams and simultaneously severing said collapsed tube along a line closely adjacent to said transverse sealed seams;
(g) removing the four double film triangular regions bounded by said diagonal seams, said transverse seam and the side edges of said tube.
(a) means for forming a tube of thermoplastic film;
(b) means for collapsing said tube including means for simultaneously forming therein two oppositely disposed, parallel, gussets;
(c) means for opening, simultaneously or spatially sequentially, a gusset fold on each side of said collapsed tube to their full, lay-flat extent;
(d) means for simultaneously or spatially sequentially forming in each of the four gusset folds a diagonal seam over the portion of the tube width corresponding to the gussets along lines diagonal to the length of the tube so that the ends of the sealed seams of adjacent gusset folds are at least closely spaced or in contact so as to form an angle of at least approximately 90°;
(e) means for returning said gusset folds to their original position so that their seal-pairs are superimposed;
(f) means for forming a transverse sealed seam across said tube along a line which includes the inboard ends of said pairs of diagonal seams and means for simultaneously forming a pre-weakened transverse line closely adjacent and parallel to said transverse sealed seams;
(g) means for removing four double film triangular regions bounded by said diagonal seams said transverse seam and the side edges of said tube; and
(h) means for collecting the resulting structures while still interconnected at said pre-weakened transverse lines.
(a) means for forming a tube of thermoplastic film;
(b) means for collapsing said tube including means for simultaneously forming therein two oppositely disposed, parallel, gussets;
(c) means for opening, simultaneously or spatially sequentially, a gusset fold on each side of said collapsed tube to their full lay-flat extent;
(d) means for simultaneously or spatially, sequentially forming in each of the four gusset folds, a diagonal sealed seam over the portions of the tube width corresponding to the gussets along lines diagonal to the length of the tube so that the ends of the sealed seams of adjacent gusset folds are at least closely spaced or in contact so as to form an angle of at least approximately 90°;
(e) means for returning said gusset folds to their original position so that their seal-pairs are superimposed;
(f) means for forming a transverse sealing and severing seam across and through said collapsed tube along a line which includes the inboard ends of said pairs of diagonal seams;
(g) means for collecting the resulting structures in a stack;
(h) means for removing the four folded triangles of film between the diagonal sealed seams and the transverse sealing and severing seam to complete the bottom of the sack; and
(i) means for forming a pair of handles and sack mouth opening at the opposite end of said sack bottom.
(a) forming a tube of thermoplastic film;
(b) collapsing said tube while simultaneously forming therein two oppositely disposed, parallel gussets;
(c) opening simultaneously or spatially sequentially, a gusset fold on each side of said collapsed tube to their full lay-flat extent;
(d) simultaneously or spatially sequentially forming in each of the four gusset folds, a diagonal sealed seam over the portions of the tube width correspoinding to the gussets along lines diagonal to the length of the tube so that the ends of the sealed seams of adjacent gusset folds are at least closely spaced or in contact so as to form an angle of at least approximately 90°;
(e) returning said gusset folds to their original position so that their seal-pairs are superimposed;
(f) forming a transverse sealed seam across said tube along a line which includes the inboard ends of said pairs of diagonal seams and simultaneously forming a preweakened transverse line closely adjacent and parallel to said transverse sealed seam;
(g) collecting the resulting structure in a stack so that all of said diagonal seams are at one end of said stack; and
(h) removing the four double film triangular regions bounded by said diagonal seams, said transverse seam and the side edges of said tube.
(a) forming a tube of thermoplastic film
(b) collapsing said tube while simultaneously forming therein two oppositely disposed, parallel gussets;
(c) opening, simultaneously or spatially sequentially, a gusset fold on each side of said collapsed tube to their full lay-flat extent;
(d) simultaneously or spatially sequentially forming in each of the four gusset folds, a diagonal sealed seam over the portions of the tube width corresponding to the gussets along lines diagonal to the length of the tube so that the ends of the sealed seams of adjacent gusset folds are at least closely spaced or in contact so as to form an angle of at least approximately 90°;
(e) returning said gusset folds to their original position so that their seal-pairs are superimposed;
(f) forming a transverse sealed seam across said tube along a line which includes the inboard ends of said pairs of diagonal seams and simultaneously forming a preweakened transverse line closely adjacent and parallel to said transverse sealed seam and a second transverse sealed seam across said tube closely adjacent and parallel to said preweakened line;
(g) collecting the resulting structure in a stack so that all of said diagonal seams are at one end of said stack; and
(h) removing the four double film triangular regions bounded by said diagonal sams, said tansverse seam and the side edges of said tube; and
(i) forming a handle and sack mouth opening at the opposite end of said bottom.