Bag closure and method of making
United States Patent 3920180
A bag closure and a method of making in which a folded seam is formed about the mouth of the bag with a draw-cord or draw-tape disposed in the seam. The material forming the seam is on one or both sides of the cord or tape provided with a row of slits or holes. When holes are employed, alternate ones are connected by incisions. The rows of slits or holes, when on both sides of a seam, are staggered relative to each other and the ends thereof overlap. When the cord or tape is drawn up to close the bag, the mouth of the bag will fold up as in the case of an eyelet type closure with the fold lines occurring in about the middle of the length of a slit or about halfway between each pair of holes connected by an incision.
Application Number:
05/467643
Publication Date:
11/18/1975
Filing Date:
05/07/1974
View Patent Images:
Export Citation:
Primary Class:
Other Classes:
383/76
International Classes:
B61D47/00; B65D33/28; B65D33/16; B65D33/28
Field of Search:
229/63 150/11
Primary Examiner:
Price, William I.
Assistant Examiner:
Farrow, Douglas B.
Attorney, Agent or Firm:
Crosby, Melvin A.
Claims:
What is claimed is
1. In a closure for the mouth of a bag or the like; superposed endless strips of flexible material joined along the edges and forming an endless tubular seam, flexible means extending along the seam adapted when the effective length thereof in the seam is reduced to reduce the diameter of the closure, a row of elongated apertures in each said strip in uniformly spaced relation along the length of the strip, the apertures in one strip being displaced longitudinally a distance of about one-half the pitch of the apertures from the apertures in the other strip, reduction in the diameter of said closure by drawing up said flexible means causing folding of said seam in the region of each aperture, said flexible means emerging from a said aperture when the seam folds in the region of the aperture.
2. A closure according to claim 1 in which each aperture is in the form of a pair of holes spaced longitudinally on the respective strip, and a longitudinal incision joining the said holes.
3. A closure according to claim 1 in which said strips are integrally joined along one edge and form said seam upon folding along said one edge, and means joining the strips together along the side of the seam remote from said one edge.
4. A closure according to claim 1 in which said material is fusable plastic material, and said strips being integrally connected along one side of said seam and are fused together along the other side of said seam.
5. A closure according to claim 4 in which said strips are also fused together along said one side of said seam.
6. A closure according to claim 1 in which said apertures are in the form of slits.
7. A closure according to claim 1 in which said flexible means is a single draw element which is drawn out through at least one of said apertures to reduce the effective length thereof in said seam thereby to reduce the diameter of said closure.
8. A closure according to claim 1 in which said flexible means is a pair of draw elements which are drawn out through respective ones of said apertures to reduce the effective length thereof in said seam thereby to reduce the diameter of said closure.
9. A closure according to claim 1 which includes means integrally joining said flexible means to at least one of said strips at at least one point.
10. A closure according to claim 1 in which said flexible means is fixedly connected to at least one of said strips at substantially diametrically opposite points while draw portions are provided on said flexible means extending out of the seam about midway between said points.
11. A closure according to claim 1 in which said closure is integrally formed on the mouth of a bag or the like.
12. A closure according to claim 1 in which said closure is adapted to be placed on the mouth of a bag or the like and fixedly connected thereto.
13. A closure according to claim 1 in which the pitch of said apertures is from about 3 to about 6 centimeters and the length of each aperture is greater than one-half the said pitch.
14. A closure according to claim 1 in which the said apertures are only in the strip on the outwardly facing side of the seam.
15. A closure according to claim 1 in which each aperture is longer than the distance between adjacent ends of adjacent apertures in the respective strip.
1. In a closure for the mouth of a bag or the like; superposed endless strips of flexible material joined along the edges and forming an endless tubular seam, flexible means extending along the seam adapted when the effective length thereof in the seam is reduced to reduce the diameter of the closure, a row of elongated apertures in each said strip in uniformly spaced relation along the length of the strip, the apertures in one strip being displaced longitudinally a distance of about one-half the pitch of the apertures from the apertures in the other strip, reduction in the diameter of said closure by drawing up said flexible means causing folding of said seam in the region of each aperture, said flexible means emerging from a said aperture when the seam folds in the region of the aperture.
2. A closure according to claim 1 in which each aperture is in the form of a pair of holes spaced longitudinally on the respective strip, and a longitudinal incision joining the said holes.
3. A closure according to claim 1 in which said strips are integrally joined along one edge and form said seam upon folding along said one edge, and means joining the strips together along the side of the seam remote from said one edge.
4. A closure according to claim 1 in which said material is fusable plastic material, and said strips being integrally connected along one side of said seam and are fused together along the other side of said seam.
5. A closure according to claim 4 in which said strips are also fused together along said one side of said seam.
6. A closure according to claim 1 in which said apertures are in the form of slits.
7. A closure according to claim 1 in which said flexible means is a single draw element which is drawn out through at least one of said apertures to reduce the effective length thereof in said seam thereby to reduce the diameter of said closure.
8. A closure according to claim 1 in which said flexible means is a pair of draw elements which are drawn out through respective ones of said apertures to reduce the effective length thereof in said seam thereby to reduce the diameter of said closure.
9. A closure according to claim 1 which includes means integrally joining said flexible means to at least one of said strips at at least one point.
10. A closure according to claim 1 in which said flexible means is fixedly connected to at least one of said strips at substantially diametrically opposite points while draw portions are provided on said flexible means extending out of the seam about midway between said points.
11. A closure according to claim 1 in which said closure is integrally formed on the mouth of a bag or the like.
12. A closure according to claim 1 in which said closure is adapted to be placed on the mouth of a bag or the like and fixedly connected thereto.
13. A closure according to claim 1 in which the pitch of said apertures is from about 3 to about 6 centimeters and the length of each aperture is greater than one-half the said pitch.
14. A closure according to claim 1 in which the said apertures are only in the strip on the outwardly facing side of the seam.
15. A closure according to claim 1 in which each aperture is longer than the distance between adjacent ends of adjacent apertures in the respective strip.
Description:
The present invention relates to a draw-end or draw-tape closure for the mouths of bags or sacks, especially bags or sacks made of fusible plastic, and having at least one draw-cord or draw-tape within a seam surrounding the mouth thereof, and to a method of making such a closure.
Two types of draw-cord or draw-tape closures for bags are already known. In one type, a draw-cord or draw-tape is provided within a tubular seam located near the opening, or mouth, of the bag. In another type, a draw-cord is threaded in zig-zag fashion through eyelets disposed about the periphery of the bag at the mouth of the bag.
The known tubular seam closures have, as compared with the eyelet closures, the advantage that the draw-cord or draw-tape may be introduced into the inside of the seam by machine by simply placing the draw-cord or draw-tape on the material before the folding over thereof to form the seam at the mouth of the bag. Seam closures of this nature have the drawback that, in effecting closing of the bag mouth, a comparatively large amount of force must be applied to the draw-cord because the seam material must be crowded together as the bag mouth is drawn closed.
Further, the dimensions of the seam are reduced in that the bunched seam material reduces the passage therein and movement of the draw-cord therein is restricted. Furthermore, the nature of the closure is such that total closing of the sack or bag is not possible as the material of the seam cannot be compressed to a small dimension. The degree of closure possible is, thus, less than that possible with an eyelet type closure.
With an eyelet type closure, on the other hand, the material at the opening is not crumpled together upon closing but is, rather, drawn into regular zig-zag folds, the folds coming to lie in the middle between two eyelets. Because the eyelet openings are not reduced, there is no clamping effect on the cord of the tape to resist movement of the cord or tape. The necessary traction force for the closing of the closure is thereby smaller than in the case with seam closures. However, the eyelet seam has the disadvantage that the threading of the draw-cord into the eyelets is necessarily done by hand and cannot be done by an automatic production process.
BRIEF SUMMARY OF THE INVENTION:
The cord pull closure according to the invention is characterized in that at least one of the two material strips forming the seam has a row of holes or slits extending in the longitudinal direction of the seam facilitating, upon drawing together, a formation of folds in the seam.
The closure according to the present invention is also characterized in that in a material web, preferably a plastic sheet material, a row of holes or slits is made along a longitudinal edge and on both sides of the fold line near the edge after which a draw-cord or tape is positioned to overlie one of the rows of holes or slits and then a seam is made by folding an edge strip about the fold line and by forming a longitudinal weld line in the strip on one or both sides of the region containing the cord or tape.
When the cord or tape is drawn up, a regular folding of the seam is achieved. Furthermore, as irregular crumpled zones which would prevent the movement of the draw-cord or the draw-tape in the openings are obviated, only a comparatively small traction force is necessary for the drawing together of the closure. As a result, thinner draw-cords or tapes may be used, and this, in turn, helps in the production of an improved seam. Furthermore, the manufacture of this draw-cord closure by machine can be effected, avoiding manual work so that mass production at low price is possible.
The object of the present invention is to provide a draw-cord or like closure and a method of making, in which even large closure lengths can be closed with comparatively small traction force to a small remaining opening and which can be made simply and cheaply by machine avoiding manual work.
The invention will now be described further, by way of example only, with reference to the following specification, taken in connection with the accompanying drawings in which:
FIG. 1 shows a part of a draw-cord closure in perspective view.
FIG. 2 is a plan view of a draw-cord closure in the flat state, the draw-cord having been omitted in the interests of clarity.
FIG. 3 is a plan view of the edge area of a slitted sheet before folding the same to form the seam.
FIG. 4 is a perspective view of the upper part, or mouth, of a bag having a draw-cord closure according to the present invention.
FIG. 5 is a view corresponding to FIG. 2 and shows a modification wherein a draw-tape is utilized.
FIG. 6 is a view corresponding to FIG. 3 and shows an edge area of a sheet before folding of the seam to produce the arrangement according to FIG. 5.
DETAILED DESCRIPTION OF THE INVENTION:
The draw-cord or draw-tape closure hereafter to be described is intended for use in the context of bags or sacks, and has particular reference to refuse sacks made of fusible synthetic plastic sheet materials.
In a seam 2 formed along the opening, or mouth, of the bag or sack there is located a draw-cord or a draw-tape 3. The seam 2 includes rows of holes or slits, one such row being provided in the front material strip 5 and another in the rear material strip 6. The slits 7, 8 in the material strips 5 and 6 respectively, are displaced relative to one another in longitudinal direction, as is apparent from FIGS. 2 and 3. The slits 7 and 8 are preferably of the same shape and length and are respectively disposed at opposite sides of a fold line 14.
The length l of each slit 7, 8 is preferably a little greater than one-half of the pitch t of the slits of a given row thereof so that the ends of the slit after the forming of the seam by folding rear material strip 6 about fold line 14 have an overlapping area 24, as can be seen in FIG. 2.
The width b of the slits 7, 8 is at least equal to the diameter of the draw-cord or to the width of the flat draw-tape 3, so that the cord or tape 3 can easily be drawn through the slits 7, 8 on closing the bag to which the closure is applied, as can be seen in FIG. 1.
The pitch t of the slits 7, 8 is equal to at least one-half of the width e of the seam and is preferably greater than such width e.
The pitch t of the slits 7, 8 conveniently lies between 3 and 6 cms and is preferably approximately 4 cm.
On closing the draw-cord closure, the seam material is, thus, not crumpled together irregularly, but is formed into zig-zag shaped folds 9, 10 such that the cord or the tape 3 separates from the seam within the range of each of the slits 7, 8, as can be seen in FIG. 1. In consequence, the traction force necessarily applied to the draw-cord or draw-tape 3 for closing the bag is substantially less than if there were no such slits 7, 8 present.
The ready formation of folds and the free movement of the draw-cord or draw-tape 3 in the seam 2 is improved still further if, in addition to the weld seam 13 which serves to close the seam 2, a further weld seam 12 is formed adjacent and parallel to the upper seam edge 4. The two weld seams 12, 13 serve positively to locate the draw-cord or draw-tape 3 in the area of the slits 7 and 8 while also causing the remaining part of the seam 2 to lie flat. The weld seam 12 also reduces the possibility of tearing the seam 2 by pulling the cord or tape 3 upward (as seen in FIG. 1).
It will be evident that the seam 2 may also be formed from two separate material strips 5, 6 placed over one another and connected by weld seams 12, 13, instead of being formed by folding over an edge region, if so desired.
Instead of elongated slits 7, 8 as illustrated in FIGS. 1 to 3, round or oval holes as shown in FIGS. 5 and 6 could be provided. Instead of rows of holes or slits in both strips of material 5 and 6, rows of holes or slits in one only of the strips may suffice. If the holes or slits are only provided at that part of the seam which lies at the outside of the bag, it is possible to produce a bag which can be closed to form an almost airtight and water-tight closure.
FIGS. 5 and 6 show a modified arrangement wherein oval holes 17, 18 are utilized, the respective rows of holes being provided at opposite sides of the fold line 14, and corresponding holes of the two rows being arranged in directly opposed disposition as distinct from being displaced in the longitudinal direction of the seam. Successive pairs of holes 17, 18 are joined by means of an incision 15, incisions 15 of one row of holes being displaced relative to those of the other row, the openings thus having an I-shape.
Upon pulling the draw-cord or draw-tape to close the closure, the bag will fold inwardly between holes on the outer wall of the seam which are joined by incisions, and the flaps 23 lying at either side of the incision bend out to give free passage for the draw-cord or draw-tape 3, so that a similar action to that of the embodiment of FIGS. 1 to 3 wherein elongated slits are utilized results. On the inner wall of the seam, the bag folds toward the outside between holes that are joined by an incision.
In either modification, in order to prevent the draw-cord or draw-tape 3 from being withdrawn from the seam 2, a transverse weld seam 20 (FIG. 4) is formed approximately midway between the projecting ends of the cord or tape 21. If preferred, the two ends of the cord or tape 21 which project from one of the openings of the seam 2 may be connected to form an endless draw-cord or draw-tape.
The rows of holes or slits 7, 8 and 17, 18 respectively are formed before the welding of the seam in a flat unfolded plastic sheet at each side of and parallel to the fold line 14, the latter itself being parallel to a longitudinal edge 25 of the sheet. Following the making of the holes or slits, the draw-cord or the draw-tape 3 is placed flat on the sheet parallel to and overlying a row of holes or slits, as seen in FIG. 3.
The draw-cord or draw-tape 3 thus does not need to be looped through the holes or slits. The seam 2 is formed by folding the outer marginal material strip 6 along the fold line 14 over the tape 3 and then forming a longitudinally extending weld to give wel seam 13. Weld seam 12 is produced either simultaneously with the formation of weld seam 13, or subsequently thereto. These operations may be carried out either continuously or step-wise. The welding is advantageously accomplished by heated rollers but the cementing together of the plastic material, or fusing together thereof by use of a solvent, are not excluded.
It is also possible to make the closure part as a separate entity which is subsequently connected to the sack or bag by, for example, a weld seam such as a heat weld, or by cementing, or by solvent fusing.
In another arrangement, not shown, two parallel draw-cords or draw-tapes may be provided, the draw-cords or draw-tapes emerging from the seam at respective, diametrically opposed portions. In this way, a closure closing toward the middle of the sack or bag is obtained. Such a closure is especially suitable for large bags, such as refuse sacks, for example.
Modifications may be made within the scope of the appended claims.
Two types of draw-cord or draw-tape closures for bags are already known. In one type, a draw-cord or draw-tape is provided within a tubular seam located near the opening, or mouth, of the bag. In another type, a draw-cord is threaded in zig-zag fashion through eyelets disposed about the periphery of the bag at the mouth of the bag.
The known tubular seam closures have, as compared with the eyelet closures, the advantage that the draw-cord or draw-tape may be introduced into the inside of the seam by machine by simply placing the draw-cord or draw-tape on the material before the folding over thereof to form the seam at the mouth of the bag. Seam closures of this nature have the drawback that, in effecting closing of the bag mouth, a comparatively large amount of force must be applied to the draw-cord because the seam material must be crowded together as the bag mouth is drawn closed.
Further, the dimensions of the seam are reduced in that the bunched seam material reduces the passage therein and movement of the draw-cord therein is restricted. Furthermore, the nature of the closure is such that total closing of the sack or bag is not possible as the material of the seam cannot be compressed to a small dimension. The degree of closure possible is, thus, less than that possible with an eyelet type closure.
With an eyelet type closure, on the other hand, the material at the opening is not crumpled together upon closing but is, rather, drawn into regular zig-zag folds, the folds coming to lie in the middle between two eyelets. Because the eyelet openings are not reduced, there is no clamping effect on the cord of the tape to resist movement of the cord or tape. The necessary traction force for the closing of the closure is thereby smaller than in the case with seam closures. However, the eyelet seam has the disadvantage that the threading of the draw-cord into the eyelets is necessarily done by hand and cannot be done by an automatic production process.
BRIEF SUMMARY OF THE INVENTION:
The cord pull closure according to the invention is characterized in that at least one of the two material strips forming the seam has a row of holes or slits extending in the longitudinal direction of the seam facilitating, upon drawing together, a formation of folds in the seam.
The closure according to the present invention is also characterized in that in a material web, preferably a plastic sheet material, a row of holes or slits is made along a longitudinal edge and on both sides of the fold line near the edge after which a draw-cord or tape is positioned to overlie one of the rows of holes or slits and then a seam is made by folding an edge strip about the fold line and by forming a longitudinal weld line in the strip on one or both sides of the region containing the cord or tape.
When the cord or tape is drawn up, a regular folding of the seam is achieved. Furthermore, as irregular crumpled zones which would prevent the movement of the draw-cord or the draw-tape in the openings are obviated, only a comparatively small traction force is necessary for the drawing together of the closure. As a result, thinner draw-cords or tapes may be used, and this, in turn, helps in the production of an improved seam. Furthermore, the manufacture of this draw-cord closure by machine can be effected, avoiding manual work so that mass production at low price is possible.
The object of the present invention is to provide a draw-cord or like closure and a method of making, in which even large closure lengths can be closed with comparatively small traction force to a small remaining opening and which can be made simply and cheaply by machine avoiding manual work.
The invention will now be described further, by way of example only, with reference to the following specification, taken in connection with the accompanying drawings in which:
FIG. 1 shows a part of a draw-cord closure in perspective view.
FIG. 2 is a plan view of a draw-cord closure in the flat state, the draw-cord having been omitted in the interests of clarity.
FIG. 3 is a plan view of the edge area of a slitted sheet before folding the same to form the seam.
FIG. 4 is a perspective view of the upper part, or mouth, of a bag having a draw-cord closure according to the present invention.
FIG. 5 is a view corresponding to FIG. 2 and shows a modification wherein a draw-tape is utilized.
FIG. 6 is a view corresponding to FIG. 3 and shows an edge area of a sheet before folding of the seam to produce the arrangement according to FIG. 5.
DETAILED DESCRIPTION OF THE INVENTION:
The draw-cord or draw-tape closure hereafter to be described is intended for use in the context of bags or sacks, and has particular reference to refuse sacks made of fusible synthetic plastic sheet materials.
In a seam 2 formed along the opening, or mouth, of the bag or sack there is located a draw-cord or a draw-tape 3. The seam 2 includes rows of holes or slits, one such row being provided in the front material strip 5 and another in the rear material strip 6. The slits 7, 8 in the material strips 5 and 6 respectively, are displaced relative to one another in longitudinal direction, as is apparent from FIGS. 2 and 3. The slits 7 and 8 are preferably of the same shape and length and are respectively disposed at opposite sides of a fold line 14.
The length l of each slit 7, 8 is preferably a little greater than one-half of the pitch t of the slits of a given row thereof so that the ends of the slit after the forming of the seam by folding rear material strip 6 about fold line 14 have an overlapping area 24, as can be seen in FIG. 2.
The width b of the slits 7, 8 is at least equal to the diameter of the draw-cord or to the width of the flat draw-tape 3, so that the cord or tape 3 can easily be drawn through the slits 7, 8 on closing the bag to which the closure is applied, as can be seen in FIG. 1.
The pitch t of the slits 7, 8 is equal to at least one-half of the width e of the seam and is preferably greater than such width e.
The pitch t of the slits 7, 8 conveniently lies between 3 and 6 cms and is preferably approximately 4 cm.
On closing the draw-cord closure, the seam material is, thus, not crumpled together irregularly, but is formed into zig-zag shaped folds 9, 10 such that the cord or the tape 3 separates from the seam within the range of each of the slits 7, 8, as can be seen in FIG. 1. In consequence, the traction force necessarily applied to the draw-cord or draw-tape 3 for closing the bag is substantially less than if there were no such slits 7, 8 present.
The ready formation of folds and the free movement of the draw-cord or draw-tape 3 in the seam 2 is improved still further if, in addition to the weld seam 13 which serves to close the seam 2, a further weld seam 12 is formed adjacent and parallel to the upper seam edge 4. The two weld seams 12, 13 serve positively to locate the draw-cord or draw-tape 3 in the area of the slits 7 and 8 while also causing the remaining part of the seam 2 to lie flat. The weld seam 12 also reduces the possibility of tearing the seam 2 by pulling the cord or tape 3 upward (as seen in FIG. 1).
It will be evident that the seam 2 may also be formed from two separate material strips 5, 6 placed over one another and connected by weld seams 12, 13, instead of being formed by folding over an edge region, if so desired.
Instead of elongated slits 7, 8 as illustrated in FIGS. 1 to 3, round or oval holes as shown in FIGS. 5 and 6 could be provided. Instead of rows of holes or slits in both strips of material 5 and 6, rows of holes or slits in one only of the strips may suffice. If the holes or slits are only provided at that part of the seam which lies at the outside of the bag, it is possible to produce a bag which can be closed to form an almost airtight and water-tight closure.
FIGS. 5 and 6 show a modified arrangement wherein oval holes 17, 18 are utilized, the respective rows of holes being provided at opposite sides of the fold line 14, and corresponding holes of the two rows being arranged in directly opposed disposition as distinct from being displaced in the longitudinal direction of the seam. Successive pairs of holes 17, 18 are joined by means of an incision 15, incisions 15 of one row of holes being displaced relative to those of the other row, the openings thus having an I-shape.
Upon pulling the draw-cord or draw-tape to close the closure, the bag will fold inwardly between holes on the outer wall of the seam which are joined by incisions, and the flaps 23 lying at either side of the incision bend out to give free passage for the draw-cord or draw-tape 3, so that a similar action to that of the embodiment of FIGS. 1 to 3 wherein elongated slits are utilized results. On the inner wall of the seam, the bag folds toward the outside between holes that are joined by an incision.
In either modification, in order to prevent the draw-cord or draw-tape 3 from being withdrawn from the seam 2, a transverse weld seam 20 (FIG. 4) is formed approximately midway between the projecting ends of the cord or tape 21. If preferred, the two ends of the cord or tape 21 which project from one of the openings of the seam 2 may be connected to form an endless draw-cord or draw-tape.
The rows of holes or slits 7, 8 and 17, 18 respectively are formed before the welding of the seam in a flat unfolded plastic sheet at each side of and parallel to the fold line 14, the latter itself being parallel to a longitudinal edge 25 of the sheet. Following the making of the holes or slits, the draw-cord or the draw-tape 3 is placed flat on the sheet parallel to and overlying a row of holes or slits, as seen in FIG. 3.
The draw-cord or draw-tape 3 thus does not need to be looped through the holes or slits. The seam 2 is formed by folding the outer marginal material strip 6 along the fold line 14 over the tape 3 and then forming a longitudinally extending weld to give wel seam 13. Weld seam 12 is produced either simultaneously with the formation of weld seam 13, or subsequently thereto. These operations may be carried out either continuously or step-wise. The welding is advantageously accomplished by heated rollers but the cementing together of the plastic material, or fusing together thereof by use of a solvent, are not excluded.
It is also possible to make the closure part as a separate entity which is subsequently connected to the sack or bag by, for example, a weld seam such as a heat weld, or by cementing, or by solvent fusing.
In another arrangement, not shown, two parallel draw-cords or draw-tapes may be provided, the draw-cords or draw-tapes emerging from the seam at respective, diametrically opposed portions. In this way, a closure closing toward the middle of the sack or bag is obtained. Such a closure is especially suitable for large bags, such as refuse sacks, for example.
Modifications may be made within the scope of the appended claims.