US3750937A

US3750937A - Plastic bag with easy-open feature

Info

Publication number: US3750937A
Application number: US00190547A
Authority: US
Inventors: R Goodwin
Original assignee: Bemis Co Inc
Current assignee: Amcor Flexibles North America Inc
Priority date: 1971-10-19
Filing date: 1971-10-19
Publication date: 1973-08-07
Anticipated expiration: 1990-08-07

Abstract

A plastic bag having a gussetted bottom and sealed at both sides, and having special end formations for the gussetted bottom such as to provide a tab at the lower end of each side seal when the bag is packed, either of these tabs being adapted to be grasped and pulled upwardly toward the upper end of the bag to tear the bag open.

Description

United States Patent [1 1 Goodwin 1 Aug. 7, 1973 PLASTIC BAG WlTH EASY-OPEN FEATURE [75] Inventor: Ralph C. Goodwin, Wayzata, Minn.

[73] Assignee: Bemis Company, Inc., Minneapolis,

Minn.

[22] Filed: Oct. 19, 1971 [21] Appl. No.: 190,547

[52] US. Cl. 229/66, 229/61 [51] Int. Cl 865d 33/00 [58] Field of Search 229/66, 57, 61

[56] References Cited UNITED STATES PATENTS Kugler 229/57 Primary ExaminerSamuel B. Rothberg Assistant Examiner-Stephen P. Garbe Attorney-Irving Powers et al.

[57] ABSTRACT A plastic bag having a gussetted bottom and sealed at both sides, and having special endl formations for the gussetted bottom such as to provide a tab at the lower end of each side seal when the bag is packed, either of these tabs being adapted to be grasped and pulled upwardly toward the upper end of the bag to tear the bag open.

8 Claims, 10 DrawingFigures minnows new SHEEI 2 0f 2 FIG-6 FIG] PLASTIC BAG WITH EASY-OPEN FEATURE BACKGROUND OF THE INVENTION This invention relates to plastic bags, made of polyethylene, for example, and more particularly to an easy-open feature for such bags.

The invention is especially concerned with what is termed a baler bag, i.e., a relatively large bag used as a master container for smaller packages, and particularly smaller filled bags such as five and ten pound bags of flour, sugar, pet food, etc., and with such a baler bag that is applied in stretched condition around its contents.

. SUMMARY OF THE INVENTION Among the several objects of this invention may be noted the provision of a plastic bag, and especially one useful as a stretch baler bag such as above-mentioned, which has an easy-open feature for tearing the bag open for removal of its contents avoiding any necessity for cutting such as might damage the contents of the bag; and the provision of a plastic bag with such a feature in a mannerwhichnot onlydoes not interfere with the stretchability of the bag for stretch baling, but which is also most simple and economical.

In general, a bag of this invention is made of heatsealable sheet plastic material with a gussetted bottom comprising two opposed gusset panels each joined to a respective wall of the bag at a bottom fold of and eittending upwardly from the bottom folds between said walls and joined together at their topby a fold constituting the central fold of the gussetted bottom. The

lengthof each of saicl bottom folds is less than the width of the bag. The gussetted bottom is adaptedto unfold and lie flat when the bag is packed. The lower portion of each wall below the level of said central fold and the respective underlying gusset panel each have end edges at each end thereof extending from the respective end of the respective bottom fold at an angle thereto upwardly and outwardly to a pointspaced inwardly from the respective side of the bag and below the level of the central fold and these end edges are heat-sealed together to form angled end edge seals, and further have heat-sealed tab-forming edge portions between said point and the respective side edge of the bag. When it is packed, the bag has a generally rectangular flat bottom formation constituted by the portion of the two gusset panels between said bottom folds unfolded and lying flat therebetween, and side panels extending up from the ends of said bottom formation. The said angled end edge seals extend upwardly and converge toward one another from the comers of said rectangular bottom formationat the lower end'of each of said side panels, and the packed bag further has a tab at each side thereof constituted by the portions of the bag walls and gusset panels bounded by the said heat-sealed tabforming edge portions overlying the side panel atthe upper end of said angled edge sealsvadapted to be grasped and pulled up to tearthe bag open along the side panel. y

Other objects and features will be in part apparent and in part pointed out hereinafter. l

. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 2 is a view of the lower end of a bag of this invention made according to FIG. I, on a larger scale than FIG. 1, showing the bag in its flat condition as manufactured, and before it is packed;

FIG. 3 is a perspective view of the lower end of the bag as it appears when packed; l

FIG. 4 is an end elevation of the lower part of the packed bag; i i l FIG. 5 is a section on line 5-5 of FIG. 2 with the bag walls spread somewhat open to show detail;

FIG. 6 is a section on line 6-6 of FIG; 5;.

FIG. 7 is a view similar to FIG. 6 showing a modifica- Corresponding reference characters indicate corresponding parts throughout the several views of the drawings.

' DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring first to FIG. I of the drawings, there is indicated at. l a length. of a center-folded web of heat sealable sheet plastic material such as polyethylene. The twohalves of the center-folded] web are each designated 3.,Rand the center fold (which joins these two halves along the longitudinal center. line of the web) is designated 5. The center-folded web 1 is shown in FIG 1 as being fed forward toward the right. As-the webis fed forward, a band or stripe 7 of a rnateri al constitutinga heat-sealsinhibiting or release'coatiriglis applied to one .face thereof (the upper face as shown in FIG. 1) extending longitudinally of the web spaced from but adjacent the center fold 5. The heat-seal-inhibiting or release material may be a commercially available polyamide'based ink, which may be unpigmented so as to be clear and invisible on the polyethylene, or which may be pigmented and printed as part of a brand pat tern on the web.

As the web is fed forward, and after it has been printed with the heat seal-inhibiting stripe it is provided with a gussetgene'rally designated 9 along its closed longitudinal margin (the margin which includes fold 5). The gusset is formed by tucking in the margins of the two halves of the web and reversing the fold 5 as shown. The two folded-in portions which become the two opposed panels of the gusset are each designated 1 1. Each of theseis joined to the respective half of the web at a fold line 13 and the two gussetpanels Ilare joined together along the reversed fold -line,.S. The

of one of the gussetpanels ll). Theiparticulars of this width will be specified later. The spacing of the stripe from the original fold 5ais such-that whenthe gusset is intucked,the stripe is located on that surface of one of the :gusset panels 11 whichfaces theothergussetpanel ll (thisis the surface of the gusset panel which faces outward when the gusset unfolded flat), with one edge 7a of the stripe extending allong the respective fold line 13 andthe other edge7b of the stripe spaced outwardly (downwardly) from the reversed central :fold

Following the intucking of the gusset 9, the web 1 is heat-sealed and segmented on lines indicated at in FIG. 1 extending transversely of the web spaced at bag width intervals to form individual bags B each having a gussetted bottom provided by the gusset 9 and an open mouth opposite the bottom as indicated at 17. As will be understood by those conversant with the art of manufacturing plastic bags with heat-sealed seams at both sides, the two opposite walls, each designated 19, of each bag are heat-sealed together on each side of the line 15 of sealing and segmenting to form a bag side seal designated 21. In accordance with this invention, the web 1 with the intucked gusset 9 is also heat-sealed and segmented on lines such as indicated generally at 23 in FIG. 1 leaving notches such as indicated at 25 in FIG. 1 at the end of each line 15 toward the gussetted margin of the web. This heat-sealing and segmenting on lines 23 is such that the length of each bottom fold 13 of the bag is less than the width of the bag. It is also such that the lower portion of each wall 19 of the bag and the respective underlying gusset panel 11 each have end edges indicated at 27 at each end thereof extending from the respective end of the respective bottom fold 13 at an angle of 45 to the line thereof upwardly and outwardly to a point 29 spaced inwardly from the respective side of the bag and below the level of the central gusset fold 5. These angled edges are heat-sealed together to form angled end seals, and it will be observed that there are two such seals designated 27 at each end of the bag bottom, one in front and one in back. The heat-sealing and segmenting on lines 23 is also such as to form heat-sealed tab-forming edge portions 31 in continuation of seals 27 extending laterally outward to the respective side edge or side seal 21 of the bag. Each bag wall 19 and the respective gusset panel 11 are heat-sealed together all along these edges at 27 and 31 from the end of the said bottom fold 13 out to the respective side edge or side seal 21 of the bag, but it will be observed that the two two-layer portions at the bottom of the flat unfilled bag, one constituted by one gusset panel 11 and the overlying lower portion 19a of the resepective wall of the bag and the other constituted by the other gusset panel 11 and the overlying lower portion 19a of the other wall of the bag, are wholly free of one another due to the interposition of the heat-seal-inhibiting material at 7, preventing the heat-sealing together at 27 and 31 of the stated twolayer portions.

As shown in FIG. 2, the lines of seal 31 are inclined slightly upwardly from points 27 outward to the lower ends of the side seals 21 of the bag (preferably at an angle of approximately 10 to the horizontal). The width of the stripe 7 is such that its upper edge 7b is at a level below the level of the lower ends of the bag side seals 21 (and above the level of points 29) so that full sealing of the side edges of the bag at 21 all the way down to the lower ends of the side edges is assured. The critical factor here is that the upper edge 7b of stripe 7 terminates at the lines of seal 31 between points 29 and the lower ends of the side edges of the bag so that there is no interference from the stripe 7 to the formation of the bag side seals 21 (see particularly FIG. 6). An alternative and equivalent arrangement is shown in FIG. 7, wherein the lines of seal 31a corresponding to lines 31 are horizontal (e.g., parallel to the bag ends) instead of being inclined like lines 31, and for purposes of non-interference with the formation of the bag side seals 21, the stripe 7 is formed with gaps such as indicated at 33 in FIG. 7 at the location of lines 15 in FIG. 1 whereby the upper edge portions 7b of the stripes which remain when notches 25 are formed terminate short of the side edges of the bags.

The construction of the bag with the ends of the bottom portion formed as shown and above described is such that when the bag is packed (e.g., stretched, loaded with a plurality of smaller packages, and allowed to contract around the smaller packages), it has a generally rectangular bottom formation such as indicated at 35 in FIG. 3 constituted by the portion of the two gusset panels 11 between the bottom folds 13 unfolded and lying flat between these folds 13. The walls 19 of the bag extend up from the bottom folds 13 at the front and back of the bag and side portions of these walls form generally rectangular side panels indicated at 37 extending up from the ends of the rectangular bottom formation 35. The inclined seals 27 at each end of the rectangular bottom formation are angled (at 45) and converge toward one another upwardly in the lower endportions of the side panels 37 from the corners 39 of the rectangular bottom formation and these seals in conjunction with lines 41 of fold in continuation thereof define a generally triangular section 43 of each side panel having as its base the respective end 45 of the rectangular bottom formation 35. Further, at the lower end of each of the side seals 21 centrally of the width of each of the side panels 37, the bag has a tab 47 constituted by the portions of the bag walls and the gusset panels 11 above the lateral tab-forming seals 31 overlying the upper portion of the respective triangular section 43. 1

Each tab 47 forms a pocket at the upper end of the triangular section 43 for upward reception of one or more fingers of the hand for grasping the tab to pull it upward. By pulling it upward, the bag is readily torn open on lines starting at points 29 (where the stress caused by the pulling is concentrated) and continuing up the side panel 37.

FIGS. 8-10 illustrate a modification in which each triangular tab 47 has an extension 49 extending downwardly therefrom adapted to be more readily grasped and pulled to tear the bag open. To form these extensions, the heat-sealing and segmenting at 23 is such that the edge portions from points 29 out to the side seals 21 of the bag have a portion 31a extending downward from the point 29 and a lateral portion 31b extending from the lower end of portion 31a over to the side seal 21. The heat-seal-inhibiting stripe 7 is applied with gaps such as indicated at 51 to provide for formation of the side seals 21 all the way down to the lower ends of the tab extensions 49.

In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.

As various changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. A bag made of heat-scalable sheet plastic material having a gussetted bottom comprising two opposed gusset panels each joined to a respective wall of the bag at a bottom fold and extending upwardly from the bottom folds between said walls and joined together at their top by a fold constituting the central fold of the gussetted bottom, the length of each of said bottom folds being less than the width of the bag, the gussetted bottom being adapted to unfold and lie flat when the bag is packed, the lower portion of each wall below the level of said central fold and the respective underlying gusset panel each having end edges at each end thereof extending from the respective end of the respective bottom fold at an angle thereto upwardly and outwardly to a point spaced inwardly from the respective side of the bag and below the level of said central fold and heat-sealed together to form angled end edge seals, said opposed gusset panels being free from one another between said bottom folds and said points and further having heat-sealed tab-forming edge portions between said point and the respective side edge of the bag, said bag, when packed, having a generally rectangular flat bottom formation constituted by the portion of the two gusset panels between said bottom folds unfolded and lying flat therebetween and side panels extending up from the ends of said bottom formation, with the said angled end edge seals extending upwardly and converging toward one ano her from the corners of said rectangular bottom formation at the lower end of each of said side panels, and further having a tab constituted by the portionsof the bag walls and gusset panels bounded by the said heat-sealed tab-forming edge portions overlying the side panel at the upper end of said angled edge seals adapted to be grasped and pulled'up to tear the bag open along the side panel.

2. A bag as set forth in claim 1 wherein the bag has heat-seals at both sides.

3; A bag as set forth in claim 1 wherein said angled seals are inclined at an angle of 45 to the line of the bottom folds.

4. A bag made of heat-scalable sheet plastic material having a gussetted bottom comprising two opposed gusset panels each joined to a respective wall of the bag at a bottom fold and extending upwardly from the bottom folds between said walls and joined together at their top by a fold constituting the central fold of the gussetted bottom, the length of each of said bottom folds being less than the width of the bag, the gussetted bottom being adapted to unfold and lie flat when the bag is packed, the lower portion of each wall below the level of said central fold and the respective underlying gusset panel each having end edges at each end thereof extending from the respective end of the respective bottom fold at an angle thereto upwardly and outwardly to a point spaced inwardly from the respective side of the bag and below the level of said central fold and heabsealed together to form angled end edge seals, and further having heat-sealed tab-forming edge portions between said point and the respective side edge of the bag, said bag, when packed, having a generally rectangular flat bottom formation constituted by the portion of the two gusset panels between said bottom folds unfolded and lying flat therebetween and side panels extending up from the ends of said bottom formation, with the said angled end edge seals extending upwardly and converging toward one another from the corners of said rectangular bottom formation at the lower end of each of said side panels, and further having a tab constituted by the portions of the bag walls and gusset panels bounded by the said heat-sealed tabforming edge portions overlying the side panel at the upper end of said angle edge seals adapted to be grasped and pulled up to tear the bag open along the side panel, and said bag having heat-seal-inhibiting material on that surface of one of the gusset panels which faces the other gusset panel.

5. A bag as set forth in claim. ll wherein said heatsealed tab-forming edge portions are inclined slightly upwardly and outwardly from said points to the side edges of j the bag.

6. A bag made of head-scalable sheet plastic material having a gussetted bottom comprising two opposed gusset panels each joined to a respective wall of the bag at a bottom fold and extending upwardly from the bottom folds between said walls and joined together at their top by a fold constituting the central fold of the gussetted bottom, the length of each of said bottom folds being less than the width of the bag, the gussetted bottom being adapted to unfold and lie flat when the bag is packed, the lower portion of each wall below the level of said central fold and the respective underlying gusset panel each having end edges at each end thereof extending from the respective end of the. respective bottomv fold at an angle thereto upwardly and outwardly to a point spaced inwardly from the respective side of the bag and below the level of said central fold and heat-sealed together to form angled end edge seals, and further having heat-sealed tab-forming edge portions between said point and the respective side edge of the bag, said bag, when packed, having a generally rectangular flat bottom formation constituted by the portion of the two gusset panels between said bottom folds unfolded and lying flat therebetween and side panels extending up from the ends of said bottom formation, with the said angled end edge seals extending upwardly and converging toward one another from the corners of of said rectangular bottom formation at the lower end of each of saidside panels, and further having a tab constituted by the portions of the bag walls and gusset panels bounded by the said heat-sealed tabforming edge portions overlying the side panel at the upper end of said angled edge seals adapted to be grasped and pulled up to tear the bag open along the side panel, said heat-sealed tab-forming edge portions being inclined slightly upwardly and outwardly from said points to the side edges of the bag, and said bag having heat-seals at both sides and a stripe of heat-sealinhibiting material on that surface of one of the gusset panels which faces the other gusset panel, said stripe having one edge thereof extending along the fold at the bottom of said one gusset panel and its other edge at a level between the level of said points and the lower ends of said side seals.

7. A bag as set forth in claim 2 wherein said edge portions between said points and the side edges of the bag are parallel to the bag ends.

8. A bag as set forth in claim 7 having heat-seals at both sides and a stripe of he'at-seal-inhibiting material on that surface of one of the gusset panels which faces the other gusset panel, said stripe having one edge thereof extending along the bottom fold at the bottom of said one gusset panel and its other edge at a level above said heat-sealed tab-forming edge portions and terminating short of said side seals.

Claims

1. A bag made of heat-sealable sheet plastic material having a gussetted bottom comprising two opposed gusset panels each joined to a respective wall of the bag at a bottom fold and extending upwardly from the bottom folds between said walls and joined together at their top by a fold constituting the central fold of the gussetted bottom, the length of each of said bottom folds being less than the width of the bag, the gussetted bottom being adapted to unfold and lie flat when the bag is packed, the lower portion of each wall below the level of said central fold and the respective underlying gusset panel each having end edges at each end thereof extending from the respective end of the respective bottom fold at an angle thereto upwardly and outwardly to a point spaced inwardly from the respective side of the bag and below the level of said central fold and heat-sealed together to form angled end edge seals, said opposed gusset panels being free from one another between said bottom folds and said points and further having heat-sealed tab-forming edge portions between said point and the respective side edge of the bag, said bag, when packed, having a generally rectangular flat bottom formation constituted by the portion of the two gusset panels between said bottom folds unfolded and lying flat therebetween and side panels extending up from the ends of said bottom formation, with the said angled end edge seals extending upwardly and converging toward one another from the corners of said rectangular bottom formation at the lower end of each of said side panels, and further having a tab constituted by the portions of the bag walls and gusset panels bounded by the said heat-sealed tab-forming edge portions overlying the side panel at the upper end of said angled edge seals adapted to be grasped and pulled up to tear the bag open along the side panel.

2. A bag as set forth in claim 1 wherein the bag has heat-seals at both sides.

3. A bag as Set forth in claim 1 wherein said angled seals are inclined at an angle of 45* to the line of the bottom folds.

4. A bag made of heat-sealable sheet plastic material having a gussetted bottom comprising two opposed gusset panels each joined to a respective wall of the bag at a bottom fold and extending upwardly from the bottom folds between said walls and joined together at their top by a fold constituting the central fold of the gussetted bottom, the length of each of said bottom folds being less than the width of the bag, the gussetted bottom being adapted to unfold and lie flat when the bag is packed, the lower portion of each wall below the level of said central fold and the respective underlying gusset panel each having end edges at each end thereof extending from the respective end of the respective bottom fold at an angle thereto upwardly and outwardly to a point spaced inwardly from the respective side of the bag and below the level of said central fold and heat-sealed together to form angled end edge seals, and further having heat-sealed tab-forming edge portions between said point and the respective side edge of the bag, said bag, when packed, having a generally rectangular flat bottom formation constituted by the portion of the two gusset panels between said bottom folds unfolded and lying flat therebetween and side panels extending up from the ends of said bottom formation, with the said angled end edge seals extending upwardly and converging toward one another from the corners of said rectangular bottom formation at the lower end of each of said side panels, and further having a tab constituted by the portions of the bag walls and gusset panels bounded by the said heat-sealed tab-forming edge portions overlying the side panel at the upper end of said angle edge seals adapted to be grasped and pulled up to tear the bag open along the side panel, and said bag having heat-seal-inhibiting material on that surface of one of the gusset panels which faces the other gusset panel.

5. A bag as set forth in claim 1 wherein said heat-sealed tab-forming edge portions are inclined slightly upwardly and outwardly from said points to the side edges of the bag.

6. A bag made of head-sealable sheet plastic material having a gussetted bottom comprising two opposed gusset panels each joined to a respective wall of the bag at a bottom fold and extending upwardly from the bottom folds between said walls and joined together at their top by a fold constituting the central fold of the gussetted bottom, the length of each of said bottom folds being less than the width of the bag, the gussetted bottom being adapted to unfold and lie flat when the bag is packed, the lower portion of each wall below the level of said central fold and the respective underlying gusset panel each having end edges at each end thereof extending from the respective end of the respective bottom fold at an angle thereto upwardly and outwardly to a point spaced inwardly from the respective side of the bag and below the level of said central fold and heat-sealed together to form angled end edge seals, and further having heat-sealed tab-forming edge portions between said point and the respective side edge of the bag, said bag, when packed, having a generally rectangular flat bottom formation constituted by the portion of the two gusset panels between said bottom folds unfolded and lying flat therebetween and side panels extending up from the ends of said bottom formation, with the said angled end edge seals extending upwardly and converging toward one another from the corners of of said rectangular bottom formation at the lower end of each of said side panels, and further having a tab constituted by the portions of the bag walls and gusset panels bounded by the said heat-sealed tab-forming edge portions overlying the side panel at the upper end of said angled edge seals adapted to be grasped and pulled up to tear the bag open along the side panel, said heat-sealed tab-forming edge portions bEing inclined slightly upwardly and outwardly from said points to the side edges of the bag, and said bag having heat-seals at both sides and a stripe of heat-seal-inhibiting material on that surface of one of the gusset panels which faces the other gusset panel, said stripe having one edge thereof extending along the fold at the bottom of said one gusset panel and its other edge at a level between the level of said points and the lower ends of said side seals.

8. A bag as set forth in claim 7 having heat-seals at both sides and a stripe of heat-seal-inhibiting material on that surface of one of the gusset panels which faces the other gusset panel, said stripe having one edge thereof extending along the bottom fold at the bottom of said one gusset panel and its other edge at a level above said heat-sealed tab-forming edge portions and terminating short of said side seals.