Method and machine for forming packages of flexible material having side gussets

Abstract

The present invention relates to a method for forming packages of flexible material with a first side gusset and a second side gusset starting from a strip coming from a reel having a sliding direction. The method comprises the following steps: making the first gusset by folding close to a first side edge of the strip coming from the reel, and making the second gusset by folding the strip coming from the reel; in which the step of making the second gusset is performed on a portion of the strip which extends in the sliding direction after the step of making the first gusset was performed on the portion of the strip. Moreover, the present invention relates to a machine configured so as to carry out the method.

Claims

1. A method for forming packages of flexible material having a first side gusset and a second side gusset starting from a strip coming from a reel and having a sliding direction, said method comprising the following steps: a) making said first gusset by means of folding close to a first side edge of said strip; b) making said second gusset by means of folding said strip; and c) folding said strip so that the first side edge of said strip is at a second side edge of said strip so as to form an open tubular element; wherein said step b) is performed on a portion of said strip which extends in the sliding direction after said step a) was performed on said portion, wherein said steps a) and b) occur simultaneously during formation of different packages, but they occur one following the other with reference to a given position along said sliding direction of said strip; wherein said step c) is performed on said portion of said strip which extends in the sliding direction while said step b) is performed on said portion.

2. The method according to claim 1, wherein: said portion has a length ranging from ¼ of a height of one of the packages to four times the height of one of the packages.

3. The method according to claim 1, further comprising the following step: d) sealing the side edges of said strip so as to make a closed tubular element; wherein said step d) is performed on said portion of said strip which extends in the sliding direction after said step c) was performed on said portion.

4. The method according to claim 3, further comprising the following step: e) sealing outer side edges of the first and second gussets so as to reinforce said outer side edges; wherein said step e) is performed on said portion of said strip which extends in the sliding direction at the same time said step d) is performed on said portion.

5. The method according to claim 1, further comprising the following step: f) sealing a transverse surface of the tubular element made from said strip, wherein a seal formed by said sealing has a length equal to a distance between an outer edge of said first gusset and an outer edge of said second gusset so as to make a bottom closure of the package; wherein said step f) is performed on a portion of said tubular element which extends in the sliding direction after said step c) was performed on said portion.

6. The method according to claim 1, further comprising the following step: g) cutting the tubular element made from said strip along an axis perpendicular to a sliding direction of the tubular element so as to separate the packages of flexible material from one another.

7. The method according to claim 6, wherein said cutting step g) is followed by the following step: h) folding a surface placed at a bottom of said tubular element made from said strip along a direction perpendicular to the sliding direction of the tubular element and securing said surface by means of an application of glue so as to make a bottom of said package.

8. The method according to claim 1, wherein: said reel is unwound in a continuous manner so as to form a plurality of packages.

9. A method for forming packages of flexible material having a first side gusset and a second side gusset from a strip of the flexible material coming from a reel and having a sliding direction, said method comprising the steps of: forming the first gusset close to a first side edge of the strip of the flexible material; forming the second gusset after said step of forming the first gusset, the second gusset formed at a location intermediate the first side edge of the strip of the flexible material and an opposing second side edge of the strip of the flexible material; joining the first side edge to the second side edge of the strip of the flexible material while forming the second gusset, whereby a tube is formed; forming a seal between the first gusset and the second gusset; and cutting the flexible material adjacent the seal between the first gusset and the second gusset; wherein said steps of forming said first gusset and forming said second gusset occur simultaneously during formation of different packages, but they occur one following the other with reference to a given position along said sliding direction of said strip, whereby the packages are capable of being formed on a machine having a reduced dimension relative to a width of the strip of the flexible material.

10. A method for forming packages of flexible material having a first side gusset and a second side gusset from a strip of the flexible material having a width, coming from a reel, and having a sliding direction, said method comprising the steps of: forming the first gusset with a first gusset forming station adjacent to a first side edge of the strip of the flexible material, thereby creating a partially formed strip of flexible material having a central zone of the width; positioning a second gusset forming station downstream of the first gusset forming station and in a location at the central zone of the partially formed strip of flexible material; forming the second gusset after said step of forming the first gusset with the second gusset forming station, the second gusset formed at a location intermediate the first side edge of the strip of the flexible material and an opposing second side edge of the strip of the flexible material; joining the first side edge to the second side edge of the strip of the flexible material while forming the second gusset, whereby a tube is formed; forming a seal between the first gusset and the second gusset; and cutting the strip of the flexible material adjacent the seal between the first gusset and the second gusset; wherein said steps of forming the first gusset and forming the second gusset occur simultaneously during formation of different packages, but they occur one following the other with reference to a given position along the sliding direction of the strip of the flexible material, whereby the packages are capable of being formed on a machine having a reduced dimension relative to the width of the strip of the flexible material.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The present invention is described with reference to the accompanying drawings in which the same numbers and/or reference marks indicate the same parts and/or similar and/or corresponding parts of the system. In the drawings:

(2) FIG. 1 diagrammatically illustrates a package that can be made according to one embodiment of the present invention;

(3) FIG. 2 diagrammatically illustrates the reel from which the strip is unwound to form the package according to one particular embodiment of the present invention;

(4) FIG. 3 diagrammatically illustrates the formation of the first gusset according to one particular embodiment of the present invention;

(5) FIG. 3a shows an enlargement of a detail of FIG. 3;

(6) FIG. 4 diagrammatically illustrates the formation of the second gusset and the folding of the strip according to one particular embodiment of the present invention;

(7) FIGS. 5a-5e show a section view of the various steps of making the first and the second gusset and of folding the strip, according to one particular embodiment of the present invention;

(8) FIG. 6 shows a detail of FIG. 4 in which the tubular element is already formed but not yet closed according to one particular embodiment of the present invention;

(9) FIG. 7 diagrammatically shows the step of making the lateral seal according to one particular embodiment of the present invention;

(10) FIG. 8 diagrammatically shows the step of making the transverse seal and the K seal according to one particular embodiment of the present invention;

(11) FIG. 9 diagrammatically shows the conveying of the tubular element towards the cutting station according to one particular embodiment of the present invention;

(12) FIG. 10 shows a detail of FIG. 8;

(13) FIG. 11 shows the cutting step according to one particular embodiment of the present invention; and

(14) FIG. 12 shows the step of folding the bottom of the package according to one particular embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

(15) The present invention is described below making reference to particular embodiments, as shown in the accompanying drawings. However, the present invention is not limited to the particular embodiments described in the following detailed description and depicted in the drawings, but rather the embodiments described simply exemplify the various aspects of the present invention, the aim of which is defined by the claims. Further modifications and variants of the present invention will be clear to those skilled in the art.

(16) As shown in FIG. 1, the present invention relates to forming a package 99 of flexible material having a first side gusset 3 and a second side gusset 4. Preferably, the sizes of the first side gusset 3 and those of the second side gusset 4 are similar so as to have a symmetrical package; even more preferably they are the same. Moreover, the package preferably has a folded bottom 9 which increases the resistance of the base of the package and efficiently prevents an accidental exit of material from the inside of the package.

(17) Such package may also have very large sizes so as to allow the storage of a large quantity of material. For example, a package made according to one embodiment of the present invention may have a width equal to 300-400 mm, a height equal to 700-800 mm and a depth of 100-200 mm. However, the packages may also have larger volumes, for example they may have a volume of 20-30 litres.

(18) With reference to figures from 2 to 12, a method is described for making a package 99 like the one depicted in FIG. 1.

(19) A plurality of packages like the one shown in FIG. 1 may be made in a continuous manner from a tubular element 5 made starting from a strip 2 coming from a reel 1 which is unwound therefrom by means of the rotation of the reel 1 about its axis Ax1.

(20) Below is the presentation of the various steps starting from any strip portion 98 which, starting from reel 1, may enter the various stations in order to be processed.

(21) In the particular embodiment of FIG. 2, by rotating the reel 1 clockwise, it is possible to continuously provide the strip 2 to a first station 100 of a machine configured so as to make the packages. The machine comprises at least the first station 100 and the second station 101. For example, it is possible to make a first package 99 of flexible material from the strip portion 98. However, such strip portion 98 is depicted here only to describe and show the reader the movement of the strip 2 between one station and the other. In the drawings, for descriptive purpose, the strip portion 98 has a smaller length than the one of a package 99. Such configuration is simply due to the particular need to depict several parts of the machine within the same drawing. Therefore, those skilled in the art will understand that such portion may have different sizes as indicated in the claims, such as for example a length equal to the one of a package or preferably even greater.

(22) The strip 2, which has a first side edge 21 and a second side edge 22, is therefore conveyed along a sliding direction D1 towards the first station 100 configured so as to form the first gusset 3 by folding the strip 2 at the zone of the side edge 21 of the strip 2. As is shown in the detail of FIG. 3a, the gusset 3 preferably is made by means of folding the strip along two parallel lines 32, 33 placed close to the side edge 21 of the strip 2 having a direction parallel to the sliding direction D1 of the strip 2, and therefore forming a lateral accordion structure.

(23) Therefore, as is clear from the above description, the formation of a gusset may simply occur by folding a sheet along two parallel folding lines so as to form a concave portion. In this particular example, the concave portion is the one formed between the edge 21 and the folding line 33.

(24) Thus, there will be a strip 2 at the outlet of the first station 100 like the one inlet into the first station 100 with the only difference being that one of the two side edges of the strip 2—which in the particular case depicted in the drawing is depicted by the side edge 21—was accordion-folded so as to form the first gusset 3. Therefore, the width of the strip 2 outlet from the first station 100 is less than the one that the strip 2 had at the inlet of the first station 100 because a side part of the strip 2 was used to make the first gusset 3.

(25) The strip 2 may also preferably have a flat shape like the one it had when inlet to the first station 100, therefore having the first side edge 21 of the strip 2 in contact with the folding line 33 and the folding line 32 in contact with the strip 2. Moreover, more generally, at the outlet of the first station 100, the first gusset 3 may preferably have a flat shape, that is with a flattened, and therefore compact, accordion structure. However, it is also possible for the strip 2 outlet from the first station 100 to have a slightly open shape of the first gusset 3 in which the first side edge 21 of the strip is spaced apart from the folding line 33.

(26) As shown in FIG. 4, after the strip 2 comes out of the first station 100 with the first gusset 3 made on one of its side edges (in particular, the one to the left in the drawing), the strip 2 is conveyed into a second station 101 configured so as to fold the strip 2, thus forming the second gusset 4. For example, this operation may be performed by means of a shaper.

(27) The distance between the first station 100 and the second station 101 may be made as liked. Preferably, the strip 2 outlet from the first station 100 travels a stretch equal to at least ¼ of the height of the final package 99 before reaching the second station 101. More preferably, the strip 2 outlet from the first station 100 travels a stretch equal to at least 2/4 of the height of the final package 99 before reaching the second station 101. Even more preferably, the strip 2 outlet from the first station 100 travels a stretch equal to at least ¾ of the height of the final package 99 before reaching the second station 101. Even more preferably, the strip 2 outlet from the first station 100 travels a stretch equal to at least the height of the final package 99 before reaching the second station 101. In the latter case, the beginning of the formation of the second gusset 4 of a first package preferably occurs only after the formation of the first gusset 3 of that specific package was completed. Even more preferably, the strip 2 outlet from the first station 100 travels a stretch equal to at least 2 to 4 times the height of the final package 99 before reaching the second station 101, so as to separate the two stations even more clearly.

(28) When for example, the strip is to travel a distance equal to at least 4 times the height of the final package before reaching the second station 101, the result is that while the second gusset 4 of a package 99 is in the forming step in the second station 101, the first station 100 is making the first gusset of another package placed upstream with respect to such package 99 by at least other 4 packages. However, it is clear that the distance that the strip travels between the first station 100 and the second station 101 may be made as liked. Therefore, in the case there are particular construction needs, it is also possible for such distance to be greater than 4 times the height of the final package 99.

(29) As shown in the detail of FIG. 5, also the second gusset 4 preferably is made by means of folding the strip along parallel lines 42, 43 preferably placed in the central zone of the strip 2 having a direction parallel to the sliding direction D1 of the strip 2, and therefore forming a lateral accordion structure. Such central zone clearly refers to the central zone of the strip 2 outlet from the first station 100 and therefore, as described above, having a smaller width with respect to the strip 2 on the reel 1 from which it is unwound. It is clear here, as for the first gusset, the formation of a gusset may simply occur by folding a sheet along two preferably parallel folding lines so as to form a concave portion. In this particular example, the concave portion is the one formed between the folding line 43 and the position in which, as described below, the folding line 41 will be positioned.

(30) Moreover, the folding of the strip 2 may be performed along the folding line 41 to form an open tubular element 5, preferably simultaneously to making the second gusset 4. Therefore, the second station 101 may preferably also be configured so as to fold the strip 2 so that the first side edge 21 of the strip 2 coming from the reel 1 is at the second side edge 22 of the strip 2.

(31) FIGS. 5a-5e show a section view of the strip 2, showing the details of the various steps required for making the two side gussets.

(32) FIG. 5a shows the transverse section of a strip 2, like the one in FIG. 2, that is before entering the first station 100.

(33) Then, as shown in the section view of FIG. 5b, and as presented previously, the first gusset 3 is made by folding in the zone of the first side edge 21 of the strip 2. As specified above, the folding is performed along the two folding lines 32, 33. More specifically, the formation of the first gusset 2 is performed along the axis Ax3 depicted.

(34) Then, as shown in FIG. 5c, preferably the formation of the second gusset 4 occurs by means of folding the strip 2 along the parallel lines 41, 42, 43, placed in a central zone of the strip 2, that is along the imaginary axis Ax4 shown in the drawing. As shown in the drawing, the axis Ax4 preferably is placed in a central position between the second side edge 22 of the strip 2 and the folding line 33 of the first gusset 3.

(35) The folding process shown in FIG. 5d may preferably occur simultaneously with the forming process of the second gusset 4 shown in FIG. 5c. However, it is also possible to perform the folding process after the second gusset 4 was formed, in line with that shown in the FIGS. 5c and 5d, respectively. If the processes occur simultaneously, clearly this involves going directly from the configuration shown in FIG. 5b to the configuration shown in FIG. 5d.

(36) The folding line 41 may preferably be used as pivot about which to fold the strip 2 so as to form the open tubular element 5 in which the first edge 21 of the strip 2 and the second edge 22 of the strip 2 are placed at each other, as shown in FIGS. 5d and 5e, respectively. As shown in the drawing, the folding line 41 may preferably be close to the centre between the side edges 21 and 22 of the strip 2.

(37) At this point, the strip 2, at the outlet of the second station 101, will therefore have taken on the shape of an open tubular element 5 configured so as to have a smaller width with respect to half of the initial width of the strip 2 because part of the strip 2 was accordion-folded to form the two side gussets. Such open tubular element 5 preferably has a flat shape so as to occupy as little space as possible.

(38) As shown in FIG. 6, preferably there may be installed, between the first station 100 and the second station 101, a conveying roller 12 configured to allow an easy sliding of the strip 2 between the first station 100 and the second station 101.

(39) The section A-A of FIG. 6 shows a section view of the tubular element 5. As shown, in addition to forming the second gusset 4, the second station 101, by means of the folding step described above, allows positioning the two side edges 21, 22 of the strip 2 at each other so that the open tubular element 5 is thus ready to be closed at the first gusset 3 so as to form a true tubular element.

(40) As shown in FIG. 7, the tubular element 5 in turn is conveyed into a sealing station preferably formed by two sealers. Here, the sealers each have a pair of side sealing bars 106 configured so as to seal the surfaces next to the outer side ends of the tubular element so as to obtain a sealed surface 6 at the outer edges of each gusset. For example, such surface may have a width which may preferably vary between 3 and 15 mm.

(41) The distance between the second station 101 and the sealing station is independent from the distance between the first station 100 and the second station 101 and may be placed as desired.

(42) The sealing bars 106 may preferably be configured so as to continuously seal. This results in the sealing bars 106 being configured, during the sliding of the strip 2, so as to always be in contact with the outer edges of the gussets and by heating them, forming the sealing surfaces 6 described above. In practice, the tubular element 5 slides in the sealing bars 106, thus being continuously sealed.

(43) In the settings step, the sealing bars 106 are initially opened to accommodate a first portion of tubular element 5. After such portion is received, they preferably are closed so as to always be in contact with the tubular element 5 and so as to perform a continuous sealing. This solution is particularly advantageous because thereby it is possible to have a process for continuously making packages 99, not having to stop the rotation of the reel 1 to make such sealed surfaces 6.

(44) However, it is also possible for such sealing bars 106 to be configured so as to make a seal in an alternating manner. In this particular embodiment, it therefore is preferable for the side sealing bars 106 to have a length equal to at least the length of the package 99 so as to make one package after the other in an alternating manner.

(45) The length of the sealed surface preferably is equal to the length of the final package 99. However, in particular cases, for example in the case of making a package having a flat folded bottom, it may be possible for such folded surface to be only partly laterally sealed or not be sealed at all.

(46) In this particular embodiment, four sealed surfaces 6 are formed among which only one—that is the one at the first gusset 3 that joins a side edge 21 of the strip 2 with the other side edge 22 of the strip 2 (as shown in the detail in FIG. 5)—serves the function of closure of the tubular element. Therefore, it is also possible to install a single sealer with a single side sealing bar 106 (not depicted) configured so as to close the tubular element 5 by performing one seal alone between the first edge 21 and the second edge 22 of the strip 2.

(47) The other three sealed surfaces 6 serve the purpose of reinforcing the gussets. Indeed, it is possible that by applying a given force, for example to open the package, there is a risk for the outer folding corners 33, 41, 43 of the first and of the second gusset 3, 4 to tear. However, by reinforcing the folding corners 33, 41, 43 with such sealed surfaces 6, it is possible to effectively prevent such tears. Moreover, such sealed surfaces 6 also serve a structural function because they give increased stability and structural resistance to the package 99 and help the squaring once the package 99 is filled.

(48) As is shown, after the closure sealing occurs, the tubular element 5 preferably has a perfectly flat shape, similar to the one of a sheet. This solution is particularly advantageous because it allows simplifying the following processes such as for example, sealing the bottom, and even allows winding the tubular element onto a reel.

(49) After the sealing described above occurs, the tubular element 5 is conveyed along the conveying direction D1 into another sealing station (as shown in FIG. 8) configured so as to form the closure of each individual package.

(50) In the particular embodiment of FIG. 8, the sealing is preferably performed by means of a pair of sealing bars 108 configured so as to make two sealed surfaces 8. A first upper strip having a width equal to the width of the tubular element 5 and a second surface having a “K” shape are made. These two sealed surfaces 8 may be made both in a continuous and in an alternating manner. The K structure is particularly advantageous here because it allows closing the bottom inner edges of the package 99, thus simultaneously preventing the product from entering the gap that would be created if such sealing were not performed. Moreover, such type of sealing allows forming the square bottom of the package, giving it also an increased structural resistance and rigidity.

(51) Preferably, the sealing bars 108 are configured so as to be alternately opened and closed and so as to follow the movement of the tubular element 5. Indeed, to have a good seal, it is preferable for the sealing bars 108 to close, contacting the tubular element 5 and following the movement of the strip until the sealing is completed, and only after the sealing is completed do they open again. Then the sealing bars 108 may return to the starting position. Thereby it is possible to have a process for continuously making packages 99, not having to stop the rotation of the strip 2 to make the sealed surfaces 8 of each package.

(52) However, it is also clear that the sealed surface may have any shape such as for example, the one of two parallel strips or also the one of a single strip. The thickness of the closure sealed surface may be selected and mainly depends on the design characteristics and on the quantity of material contained in the package.

(53) At this point, in the particular embodiment depicted in FIG. 9, the tubular element 5 is conveyed into a cutting station in which there are cutting means 200 such as for example, a cutter configured so as to separate one package from the next.

(54) As shown in the detail of FIG. 10, the cutter 200 is configured so as to cut the tubular element 5 along a cutting axis Ax2 placed upstream with respect to the sealed surface. Therefore, two packages placed next to each other preferably are separated by means of the cut depicted in FIG. 11. Simultaneously, the cut will define the bottom edge of a package and the top opening mouth of a successive package.

(55) As shown in FIG. 12, the bottom edge of the package preferably is folded along a direction perpendicular to the sliding direction D1 so as to form a particularly sturdy bottom of the package 99. To this end, the folded surface 9 of the package 99 may preferably be secured, for example glued, to the main body of the package 99. To this end, hot glue points preferably are applied and the bottom is rotated by two side grippers (not depicted) preferably using the highest-positioned sealing line 8 as pivot.

(56) Then the package 99 thus formed may directly be filled (not shown) or it may be sold empty as a ready-to-be-filled package. For example, the package formed according to the present invention may be supplied to a filling machine, for example a carousel filling machine like the one described in PCT application published under number WO 2008/114113 A1.

(57) The present invention may be combined with the formation of one or more rounded edges of the package and the formation of a facilitated opening in the package, as described for example in Italian Patent Application No. 102016000034876.

(58) It is also possible to combine the present invention with the closure of the package and the formation of a handle in the package, as described in Italian Patent Application No. 102016000106959. An opening of the package may also be implemented, as described in the same Italian Patent Application No. 102016000106959.

(59) Although the present invention was described with reference to the embodiments described above, it is clear to the skilled expert that it is possible to make various modifications, variations and improvements to the present invention in light of the teaching described above and within the scope of the appended claims, without departing from the object or scope of protection of the invention.

(60) For example, individual packages separated from one another by means of cutting are the final product in the present invention. However, the cutting process may be omitted and the final product may be the tubular element which may for example, be wound onto a reel.

(61) Moreover, although the first gusset 2 in the particular embodiment presented was made at the first side edge 21 of the strip 2, it is clear to the skilled expert that the first gusset may similarly be made at the second side edge 22.

(62) Moreover, the folding process of the bottom of the package may be completely omitted.

(63) Finally, those scopes deemed to be known by skilled experts were not described to avoid uselessly excessively overshadowing the invention described.

(64) Accordingly, the invention is not limited to the embodiments described above, but is only limited by the scope of protection of the appended claims.