Side-gusset bag and method of making a side-gusset bag

Abstract

A bag has front and back face panels having upright longitudinally extending side edges and transversely extending upper and lower edges. First and second gusset panels each have transversely extending upper and lower edges and upright longitudinal outer edges connected to the longitudinal edges of the face panels. A reclosable fastener strip extends continuously and transversely along the first gusset panel and inward along each of the face panels from the first gusset panel along part of a transverse width of the face panels. Thus opening of the fastener and folding out of the first gusset panel forms a spout on the bag. A separate generally rectangular floor panel is joined at its outer edge by thermal welds to the lower edges of the face panels and of the gusset panels.

Claims

1. A method of making a bag having: identically shaped front and back face panels having upright longitudinally extending side edges and transversely extending upper and lower edges; identically shaped first and second side gusset panels each having transversely extending upper and lower edges and upright longitudinal outer edges connected to the longitudinal side edges of the face panels; and a separate generally rectangular floor panel having outer edges joined to the lower edges of the face panels and of the side gusset panels, the method comprising the steps of: longitudinally advancing a flat longitudinally elongated bag film having longitudinal film edges and two longitudinally extending halves in a longitudinally extending production direction; forming in the flat advancing bag film a succession of longitudinally spaced through cuts each extending transversely across more than one of the longitudinally extending halves of the bag film from a point spaced transversely inward of one of the longitudinal film edges and each having a length equal to a transverse width of the front panel plus twice a rectified transverse width of one of the side gusset panels, whereby the bag film remains uncut and uninterrupted along both longitudinal film edges and each through cut only extends transversely partially into the other of the longitudinally extending halves, the through cuts dividing the one longitudinal half into a longitudinal succession of the front face panels while the other of the longitudinally extending halves that will form the back panels is continuous; folding the cut and advancing bag film along longitudinal fold lines with the one longitudinally extending half on top and with the longitudinal film edges lying atop one another to form a bag tube having a longitudinal succession of the back panels, a longitudinal succession of the front panels each lying atop a respective one of the back panels and separated by the through cuts, and two longitudinal successions of side gusset panels folded between the longitudinal side edges of the face panels, extending a full longitudinal length of the respective front and back panels, and separated by the through cuts; lifting the lower edge of each of the front panels of the folded bag film at the respective through cut and fitting between each of the lifted lower edges and the lower edge of the respective back panel a respective rectangular film section to form the floor panel; joining the rectangular film sections of the folded bag film to the lower edges of the front and back panels and of the side gusset panels; trimming off the uncut longitudinal film edges of the bag film joined to the rectangular film sections; and separating the cut, folded, and welded bag film into bags by transversely severing the back panels from each other at the through cuts.

2. The method defined in claim 1, further comprising the step of: applying to the film at locations that in the separated bags lie adjacent the upper edges the reclosable fastener strips extending transversely along the first gusset panels and inward along each of the face panels from the first gusset panels along part of a transverse width of the face panels, whereby opening of a fastener formed by the fastener strips and folding out of the first gusset panel forms a spout on the bag.

3. The method defined in claim 2, wherein the fastener strips each includes a pair of contiguous strips releasably joinable to each other and either of complementary uniform cross section or having interengaging rows of complementary formations.

4. The method defined in claim 1, further comprising the step of: mounting handles on each of the second side gusset panels.

5. The method defined in claim 1, wherein when each front panel is lifted at the lower edge it is folded back to form a flap having a width equal to half of a rectified width of a one of the side gusset panels.

6. The method defined in claim 1, further comprising the step of: thermally welding the lower edges of the face panels and side gusset panels to the outer edges of the floor panel.

7. The method defined in claim 1, further comprising the step of: forming a longitudinal thickening weld along the joined longitudinal side edges of the face panels and the side gusset panels to stiffen the face panels and side gusset panels.

8. The method defined in claim 1, wherein the panels are all substantially rectangular and formed of a synthetic-resin film.

9. The method defined in claim 8, wherein each panel is formed as a laminate with a heat-weldable inner layer of polyolefin and an outer layer of polyester, the bag film being folded such that the heat-weldable inner layer forms inner surfaces of the bags.

10. The method defined in claim 1, further comprising the step of: welding together the upper edges of the face panels and gusset panels to upwardly close the bag at a top weld.

11. The method defined in claim 10, wherein the side gusset panels extend a full longitudinal length of the face panels from the top weld to the floor panel.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) The above and other objects, features, and advantages will become more readily apparent from the following description, reference being made to the accompanying drawing in which:

(2) FIG. 1 is a perspective view from below of a side-gusset valve according to the invention; and

(3) FIG. 2 is a front view of the bag when folded flat;

(4) FIG. 3A to 3F show method steps of making the side-gusset bag shown in FIGS. 1 and 2.

SPECIFIC DESCRIPTION OF THE INVENTION

(5) As seen in FIG. 1, a side-gusset bag according to the invention has two opposite and substantially identical and rectangular face panels 1a and 1b, a first side gusset panel 2a and a second side gusset panel 2b each having a center fold and formed by a pair of identical rectangular subpanels. The side gusset panels 2a and 2b extend opposite to one another in a longitudinal direction 1 and are each connected to longitudinal outer edges of the face panels 1a and 1b so as to connect them to one another.

(6) While FIG. 1 shows a filled side-gusset bag that is closed in a transverse bag direction q by an upper weld 3, FIG. 2 shows a side-gusset bag that is provided as a pre-made bag in a flat-lying state for a subsequent filling operation. In order to arrive from FIG. 2 to the filled bag according to FIG. 1, the pre-made flat-lying bag is filled at at an upper edge that initially is not closed, and is closed after filling by an upper thermal weld 3. Side edges between the face panels 1a and 1b and the side gusset panels 2a and 2b are reinforced by the longitudinal thermal welds 4.

(7) FIGS. 1 and 2 show that the bag has a reclosable fastener with a reclosable fastener strip 6. The reclosable fastener strip 6 is provided at the first side gusset panel 2a and extends over the two subpanels of the first side gusset panel 2a inserted between the face panels 1a and 1b and extending the full length of the face panels 1a and 1b. In the illustrated embodiment, the reclosable fastener strip 6 extends on the face panels 1a and 1b beyond the first side gusset panel 2a so that there, in a region adjoining the first side gusset panel 2a, the front and back face panels 1a and 1b can also be directly connected to one another. In contrast, at the first side gusset panel 2a, the two subpanels of the corresponding subpanels of the side gusset panel 2a are each connected to a respective one of the front and back face panels 1a and 1b.

(8) In order to open the side-gusset bag for the first time, a weakening line 7 above the strip 6 allows a corner section 8 to be torn off above the reclosable fastener strip 6. The weakening line 7 can be formed, for example, by stamping, a perforation or a laser, and these various measures can also be combined with one another. Also, a transversely outwardly open notch 9 is provided at the end of the tear line 7 to aid in starting the tear.

(9) In order to enable closure of the side-gusset bag after first opening, a transverse weld 10 extends from the end of the reclosable fastener strip 6 to the opposite bag edge and parallel to the upper bag edge.

(10) After first opening, the first side gusset panel 2a can be folded outward by opening the reclosable fastener formed by the reclosable fastener strip 6, thereby forming a spout, and can be inserted again between the front and back face panels 1a and 1b for reclosing.

(11) According to the invention, the side-gusset bag has a flat bottom or floor panel that is formed from a separate section 11 of film section. The film section 11 is connected to the lower edges of the face panels 1a and 1b and the side gusset panels 2a and 2b by thermal welds 12a and 12b. While the flat bottom is particularly advantageous during filling, transporting, storing and handling and enables secure placement of the side-gusset bag in an upright position, the filling material can be easily removed via the reclosable fastener and removing accurate partial quantities is also possible due to the shape of the spout.

(12) Depending on the filling weight, the side-gusset bag can also be provided with a handle that is not illustrated that, for practical reasons, is provided on the second side gusset panel 2b opposite the reclosable fastener 6.

(13) The reclosable fastener strip 6 can have continuous closure configurations in the form of grooves or projections or can have a plurality of individual closure elements that can be interlocked with one another, wherein such interlockable closure elements can have the shape of mushroom heads or velcro-type hooks.

(14) A preferred method of making the side-gusset bag of FIGS. 1 and 2 is shown in FIGS. 3A to 3F.

(15) The method includes feeding a material web 13 of a bag film 13 a production direction p hose 9 orientation corresponds to the longitudinal bag direction 1. The corresponding method is therefore also designated as a longitudinal method.

(16) According to FIG. 3A, the bag film 13 is folded in a manner known per se so as to form a side-gusset tube 14 that has a row of the first face panels 1a, a row of the second face panels 1b and two rows of the side gusset panels 2a and 2b connecting the face panels 1a and 1b. FIG. 3A shows the fold lines. In addition a handle 17 glued to one of the second panels 2b is shown.

(17) Outer edges 15 of the bag film 13 are project laterally to one side and are trimmed off after formation of the side-gusset tube 14.

(18) According to FIG. 3A, a transversely extending cut 16 is created before folding the bag film 13 for each side-gusset bag in such a manner that the cut 16 extends in the subsequently formed side-gusset bag 14 over the two side-gussets 2a and 2b and the first face panel 1a that is provided between the side-gussets 2a and 2b, but not into the edge regions that are subsequently trimmed off. As will be explained in detail below, the individual side-gusset bags are separated from the side-gusset tube 14 at the cuts 16 that are provided for forming a flat bottom.

(19) The bag film 13 is formed from at least two layers and comprises a thermally weldable inner layer made of polyolefin, in particular polyethylene, and an outer layer made of polyester, in particular PET. The film section 11 can be formed from an identical laminate. According to FIG. 3A, the thermally weldable inner layer of the bag film 13 fed in a flat state is initially exposed so that a transversely extending reclosable fastener strip 6 can also be welded thereon for each side-gusset bag. Adjacent the reclosable fastener strip 6, the weakening line 7 is already created in the flat bag film 13 so that the upper corner section 8 of the finished side-gusset bag can subsequently be detached for exposing the reclosable fastener strip 6 when opening for the first time.

(20) Since the cuts 16 extend over the first face panel 1a and the two side gusset panels 2a and 2b, the first face panel 1a can be lifted, for which purpose grippers or vacuum pads can be used, for example.

(21) FIG. 3A also shows that it is possible to make longitudinal edge-stiffening welds 4 during formation of the side-gusset tube 14. When the first face panel 1a on top is now partially folded over at the cuts 16, the two side gusset panels 2a and 2b and the second face panel 1b are partially exposed (see FIG. 3B), as a result of which the side gusset panels 2a and 2b extend there from a fold line 17 and run outward at an angle of 45. The separate film section 11 that, according to FIG. 3B, can in particular be fed from the side, is placed onto the base region that is folded open in this manner along the fold line 17.

(22) According to FIG. 3C, this separately fed film section 11 is connected to the upward-folded side gusset panels by thermal welds 12b with the side-gusset tube 14 lying flat.

(23) In order to avoid undesirable creation of a thermal weld within the side-gusset tube 14 when connecting the separate film section 11 to the first face panel 1a, as shown in FIG. 3D, the folded section of the first face panel 1a is set upright and while upright is connected to the separate film section 11 along a thermal weld 12a (FIG. 3E).

(24) However, connecting the separate film section to the second face panel 1 can also be carried out beforehand or afterward without any problems. FIG. 3F shows as an example the creation of this second thermal weld 12a immediately before cutting off the individual side-gusset bags. It is also possible to form both thermal welds 12a together when the separate film section 11 is folded down again (FIG. 3D), because then the connections of the separate film section 11 to the first face panel 1a and the second face panel 1b lie on top of one another at the lower bag edge.