BAG SUITABLE FOR PACKAGING OF FRUIT AND VEGETABLE PRODUCTS AND MEANS FOR ITS MANUFACTURE

Abstract

A bag (100) suitable for packaging fruit and vegetable products (2) comprising a casing (103) capable of housing the products to be packaged and at least one first band (104) and one second band (105) each arranged on the outer face of the casing so as to seal said casing, the first band (104) being joined to the casing only at its ends (104a, 104b) forming a handle (106) and the second band (105) joined along the length thereof to the associated face of the casing, forming a stable bottom (105c). A station (1) for producing this bag (100) comprises an expansion device (4) of tubular material comprising an upper expansion body (4a) and a lower expansion body (4b) mechanically linked to each other with a capacity for movement of one with respect to the other and that cooperate with welding groups.

Claims

1. A breathable bag especially suitable for packaging fruit and vegetable products comprising a tubular mesh casing capable of housing the products to be packaged, and at least one first band and one second band each arranged on the outer face of the casing and joined together at their ends, interposed with respective ends of the casing, so as to seal said casing, wherein the first band is joined to the casing only at its ends such that a central portion thereof is able to be separated from the body of the casing forming a handle the second band is joined along its length to the associated face of the casing, forming a stable bag bottom for the contents of the casing when the bag is suspended from the handle.

2. The bag according to claim 1 wherein the second band is joined to the associated face of the casing in a continuous fashion.

3. The bag according to claim 2 wherein the second band is joined to associated face of the casing by two longitudinal joining strips arranged at or near to the longitudinal edges of said second band.

4. The bag according to claim 1, wherein the second band forming the stable bag bottom of the casing, is a band having parallel longitudinal edges that determine a bandwidth h whose ratio to the perimeter l of the tubular casing is h/l≧0.2.

5. The bag according to claim 1, wherein at their ends of mutual joining with interposition of the casing, the mentioned first and second bands are flattened and have similar widths.

6. The bag according to claim 5, wherein the central portion of the first band has a width that is significantly smaller than the width of the joining ends thereof, with interposition of the casing, with the second band.

7. A station for producing bags for a machine for manufacturing and packaging products in bags based on the supply of a flexible tubular material and flexible sheet material in the form of a band or bands, joined on the outside to one or both sides of the mentioned tubular material, comprising an expansion device of the tubular material intended to be inserted vertically and floating inside said tubular material while producing the bags, for which the station is equipped with means of support on which the mentioned expansion device rests, although with the interposition of tubular material supplied while producing the bags, wherein the expansion device comprises: an upper expansion body intended to cooperate with at least one upper welding group for the joining of the expanded tubular material as it passes through this upper expansion body with the sheet material arranged between said tubular material and the upper welding group; and a lower expansion body intended to cooperate with at least one lower welding group for the joining of the expanded tubular material as it passes through this lower expansion body with the sheet material arranged between said tubular material and the lower welding group, the upper and lower expansion groups being mechanically linked to one another with capacity of movement respect to each other.

8. The station for producing bags according to claim 7, wherein upper expansion body and the lower expansion body are joined in an articulated manner around a transverse shaft, which becomes horizontal when the expansion device rests on the means of support.

9. The station for producing bags according to claim 7, wherein the expansion device rests on the means of support through support of the upper expansion body on said means of support, the lower expansion body being suspended from the upper expansion body.

10. The station for producing bags according to claim 7, wherein with the expansion device resting on the means of support: the upper expansion body offers one first and one second upper support faces opposite one another, each of which can be used to support the tubular material and the sheet material to be joined and against which, in this case, the welding plates of corresponding first and second upper welding groups actuate, arranged at the same level and between which the upper expansion body is located. the lower expansion body offers one first and one second lower support faces opposite one another, each of which can be used to support the tubular material and the sheet material to be joined and against which, in this case, the welding plates of corresponding first and second lower welding groups actuate, arranged at the same level and between which the lower expansion body is located, the station for producing bags being prepared both to actuate or to actuate and operate said welding groups individually, simultaneously or coordinately.

11. The station for producing bags according to claim 10, capable of operating a single upper welding group on one side of the expansion device and a single lower welding group arranged on the other side of the expansion device.

12. The station for producing bags according to claim 11, prepared so that the upper welding group and the lower welding group each on one side of the expansion device operate simultaneously.

13. The station for producing bags according to claim 7, wherein the lower expansion body comprises two parallel plates that determine two major opposing faces in the lower expansion body, each suitable for cooperating with a lower welding group, and because said plates are joined to one another, freeing the space that separates them along the entire length of at least their lateral edges, thus determining vertical slots that enable the formation of individual folds in the tubular material that surrounds it while the bags are being produced.

14. The station for producing bags according to claim 13, wherein the plates have a window into which a cover is placed, the outer surface of which is a covering material that provides non-stick properties and high resistance to heat.

15. The station for producing bags according to claim 14, wherein the covering material is made of polytetrafluoroethylene.

16. The station for producing bags according to claim 1, wherein the upper expansion body comprises a rigid support frame for two pairs of welding backs, each pair of the welding backs determining one of the support faces in the upper expansion body suitable for cooperating with an associated upper welding group.

17. The station for producing bags according to claim 16, wherein the welding backs of a same pair are mounted in a rotating way around a common shaft transverse to the upper expansion body, which is essentially horizontal when the expansion device rests on the means of support.

18. The station for producing bags according to claim 10 wherein the expansion device rests on the means of support by means of a pair of rotating rollers around rotation shafts that are parallel and at a same level, positioned on the lower end of the upper support body.

19. The station for producing bags according to claim 18, wherein the upper end of the lower expansion body is arranged between the two rotating rollers of the upper expansion body.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0044] FIGS. 1 and 2 illustrate schematically and from different points of view a bag according to the invention in a rest position;

[0045] FIG. 3 would show the shape that the same bag adopts during transport when suspended from the handle;

[0046] FIG. 4 shows a station for producing the bag according to a variant of the invention;

[0047] FIG. 5 is a side elevation view of the station shown in FIG. 1 having schematically added the supply of tubular material and the two bands of sheet material from which an open bag can be produced, for example, of the type shown in FIGS. 1 to 3;

[0048] FIG. 6 is a front elevation view of the station shown in FIG. 4 having deprived the lower expansion body of one of the support faces thereof for the tubular material and the sheet material so as to be able to show the relationship thereof with an introducer penetrating into said lower expansion body;

[0049] FIG. 7 shows a side elevation of an expansion device of a station according to the invention;

[0050] FIG. 8 shows the same expansion device according to cutting plane AA of FIG. 8;

[0051] FIG. 9 shows an enlarged view of the area delimited and indicated with legend B in FIG. 8; and

[0052] FIGS. 10 and 11 show how the position of the lower expansion body can be varied with respect to the upper expansion body in an expansion device of a station according to the invention.

DETAILED DESCRIPTION OF AN EMBODIMENT

[0053] The bag 100 illustrated by way of example in FIGS. 1 and 2 comprises a tubular mesh casing 103 selected from the cross-sectional type of a continuous tube, the ends 103a and 103b of which are closed between one first and one second band 104 and 105 of sheet material, such as thermo-weldable plastic, which are joined to one another by their opposing ends 104a, 105a and 104b, 105b interposing the respective ends 103a and 103b of the casing 103 by means of joints 108 extending transverse to the bands 104 and 105.

[0054] In the bag 100, the first band 104 has a central portion 104c that is not joined or otherwise attached in any way to the associated face of the casing 103. With the bag 100 resting on a surface, for example, of exposure (as illustrated in FIG. 1), the first band 104 is naturally positioned smoothly on said face of the casing 103. To this effect, a length is selected for the band 104 similar to the length of the casing 103.

[0055] The mentioned central portion 104c of the first band 104 is sized to act as a handle 106, being able to hold and carry the bag 100 gripped by the handle 106.

[0056] In these circumstances, the casing 103 will assume a U-shape but in a controlled or assisted manner, in this case through the second band 105. To this end, this second band 105, unlike the first band 104, is joined to the associated face of the casing along its length preventing it from being able to separate therefrom, forming a bag bottom 105c (see FIG. 2) of the bag 100 when it is carried suspended from the handle 106.

[0057] This can occur even when the first and second bands 104 and 105 are of the same length, which is very advantageous so as not to alter the usual production systems. By adopting the U-shape, the ends of the bag 100 are brought close together, and as a result, the ends 104a and 104b of the first band 104 are also brought together, which allows the central portion 104c that acts as a handle 106 to separate from the casing 103.

[0058] It is of interest that the width of the second band 105 be sufficient in order to provide the bag 100 with optimum stability during transport or to prevent unwanted twisting of the casing 103. To this effect, in a bag 100 having capacity for 6 to 15 pieces of fruit (common format in the marketing of citrus fruit, apples, etc.) it would be desirable to select a band with a width of between 90 and 160 mm as second band 105, with a length that can range between 20 and 40 cm, depending on the number of pieces to be housed in the casing 103.

[0059] In practice, the perimeter of the tubular casing 103 for this type of bag, intended to contain fruit and vegetable products, generally ranges from 400 to 600 mm, which means that by taking into account the above-mentioned widths, in a small bag an optimum perimeter/width ratio could be 400/90, which means a coverage of the second band 105 of about 40% of the web casing in the example; and in the case of a large bag, an optimum perimeter/width ratio could be 600/160, which means a coverage of about 25% of the casing 103.

[0060] In the example, the second band 105 is a straight band, in which two lateral edges are distinguished and along which, or in the vicinity whereof, there are longitudinal joining strips 107 of this band to the casing 103. The longitudinal strips may be continuous, but it is also contemplated that the joining points with the casing 103 be discreet, intermittent and having another distribution, but inasmuch as possible, ensuring that the second band 105 cannot be moved transverse to the casing 103 and is secured thereto over its entire length so as to be able to carry out the function of a bottom of the bag 100 particularly when it is carried suspended from the handle 106, as illustrated in FIG. 3.

[0061] In the example, in the areas of mutual joining the ends 103a, 104a and 103b, 104b of the first and second bands 104 and 105 are flattened and are of the same or similar width and the joining is carried out by melting (for example, by means of ultrasound or through the supply of heat) the materials that form the bands 104 and 105 or by other means such as stapling, gluing, sewing, etc. Conventionally, as described above, the joining areas may extend transversally to the bands 104 and 105.

[0062] It should be noted that the first band 104 has a slight narrowing in its central portion 104c, which favors comfortable fastening thereof when it acts as a handle 106.

[0063] FIG. 4 shows a station 1 for producing open bags for a machine for manufacturing and packaging products in bags based on the supply of flexible tubular material, such as a woven mesh or a plastic mesh, and of a flexible sheet material in the form of a band or bands.

[0064] In a known manner, the station 1 comprises an expansion device 4, or expander core, capable of being arranged in floating position or vertically inside the tubular material when it is supplied to produce bags. For this purpose, the station is equipped with a means of support 5 of the expansion device 4, in the example in the form of two rotating rollers, the shafts of which are supported on a fixed, not shown, component of the station 1.

[0065] The expansion device 4 is configured to cooperate with the welding groups capable of procuring the joining of the expanded tubular material with the sheet material as it passes through the expansion device, arranged between said tubular material and the welding groups.

[0066] The station 1 of FIG. 4 is particular in that the expansion device 4 comprises an upper expansion body 4a and a lower expansion body 4b joined in an articulated manner around a transverse shaft 6 that is essentially horizontal when the expansion device 4 is supported on the means of support 5. In the example, the expansion device 4 is supported on the means of support 5 by the lower part of the upper expansion body 4a, the lower expansion body 4b being suspended.

[0067] In order to allow feeding of the tubular material between the upper expansion body 4a and the means of support 5, said upper expansion body 4a mounts rotating rollers 13 around rotation shafts 13a (see FIG. 6) parallel and at the same level, each of which rests on one of the rotating rollers of the means of support 5.

[0068] The upper expansion body 4a is meant to cooperate with a least one upper welding group, and the lower expansion body 4b is meant to cooperate with at least one lower welding group.

[0069] In the station 1 of the example, the upper expansion body 4a has one first and one second support faces 14, 15 which are opposite one another (see FIG. 5), each of which can be used to support the tubular material and the sheet material to be joined and against which, in this case, the welding plates 16, 17 of a first and second upper welding groups 18, 19 can actuate, arranged at the same level and between which the upper expansion body 4a is located, all of which can better be appreciated in FIG. 5.

[0070] In turn, the lower expansion body 4b also offers one first and one second support faces 20, 21 opposite one another, each of which can be used to support the tubular material 2 and the sheet material 3 to be joined and against which, in this case, the welding plates 22, 23 of corresponding first and second lower welding groups 24, 25 can actuate, arranged at the same level and between which the lower expansion body 4b is located.

[0071] The station 1 is prepared both to actuate or to actuate and operate the different welding groups individually, simultaneously or coordinately. As it has been clarified previously, by operating it is understood that in addition to displacing the welding plates associated to the welding group, heat is supplied thereto so as to be able to join tubular material and sheet material by thermo welding, said material having been arranged between said welding plates and the expansion device.

[0072] The configuration of the welding plates of the upper and lower welding groups being different, the station 1 allows producing several different types of bags depending on the combination of welding groups operating on the tubular material and the sheet material to be joined together.

[0073] The station 1 is particularly advantageous when being actuated and operated simultaneously on the expansion device 4 with several welding groups, of which at least one is the upper welding group and another is the lower welding group.

[0074] One example is shown schematically in FIG. 5, suitable for producing a bag 100 as shown in FIGS. 1 to 3. A particular feature of this bag is that the casing 103 can be obtained from a tubular material 2, in the form of woven or plastic mesh, and two bands 104 and 105 of sheet material, each one applied to one side of the tubular material 2 and joined thereto in a different manner: in one case joined along the length of the tubular material 2 forming the casing 103; and in the other case, joined only to the ends of the casing 103. In the example of FIGS. 1 to 3, the bands 104 and 105 of sheet material also have different shapes.

[0075] One form for the mass production of this type of bag by means of a station 1 like that of FIGS. 4 to 6 involves supplying the tubular material 2 and the two bands 104, 105 as illustrated in FIG. 5 and simultaneously actuating the welding plates 16, 17 of the first and second upper welding groups 18, 19 against the first and second upper support faces 14, 15 of the upper expansion body 4a, respectively, but operating only with one of the upper welding groups by supplying heat only to the plates of one of these upper welding groups, for example to the plates 16 arranged on a first side L of the expansion device 4; and actuating the welding plates 22 and 23 of the two lower welding groups 24, 25 against the first and second lower support faces 20, 21 of the lower expansion body 4b, but operating only with one of these lower welding groups, supplying heat only to the plate 23 of the welding groups arranged on the side R opposite to the expansion device 4. Thus, in a same working cycle of the station 1, the sheet material 105 is joined along the length of a section of the tubular material 2 forming the casing 103 of a bag in the process of being manufactured on the L side of the expansion device 4; and the sheet material 104 is joined to one of the ends of a section of the tubular material 2 forming the casing of another bag in the course of manufacturing, which precedes the previous bag and onto which the sheet material 105 has already been joined along the length thereof, on the side R of the expansion device.

[0076] In addition to the station 1 providing support surfaces at different levels in order to cooperate with different welding groups arranged at a different level, the articulated joint between the upper and lower expansion bodies 4a and 4b makes it possible that the mechanical thrust that may be exerted by the upper welding groups on the support surfaces at its level does not result in a displacement of the lower lever support surfaces causing an undesired mismatch with the associated lower welding groups.

[0077] An example of an expansion device 4 with an articulated joint between the upper and lower expansion bodies 4a y 4b is exemplified in FIGS. 7 to 9, and its effect is illustrated in FIGS. 10 and 11.

[0078] FIGS. 7, 8 and 9 show that the upper end of the lower expansion body 4b is arranged between the two rotating rollers 13 of the upper expansion body 4a intended to rest, in rotating mode, on the means of support 5 of the station 1. As illustrated in FIGS. 10 and 11, this circumstance does not prevent the rotation of the lower expansion body 4b with respect to the upper expansion body 4a to a sufficient extent so that each of these upper and lower bodies 4a and 4b can be properly aligned with the welding plates of the upper and lower welding groups operating at their level.

[0079] In the example of these FIGS. 7, 8 and 9, the upper expansion body 4a comprises a rigid support frame 11 for two pairs of welding backs 12, each pair of welding backs determining one of the support faces 14, 15 in the upper expansion body 4a suitable for cooperating with the welding plates 17, 18 of the first and second upper welding groups 18 and 19, respectively.

[0080] The welding backs 12 of a same pair are furthermore mounted in a rotating way around a common shaft 12a, transverse to the upper expansion body 4a, which is essentially horizontal when the expansion device 4 rests on the means of support 5, which also contributes to a better accommodation of the welding plates 17 and 18.

[0081] As regards the lower expansion body 4b, in the example it comprises two parallel plates 35, 36, which determine the support faces 20 and 21 in the lower expansion body 4b, opposed to one another, each suitable for cooperating with the plate 22, 23 of a respective lower welding group 24 and 25.

[0082] The plates 35 and 36 are joined together freeing the space that separates them along the entire length of at least their lateral edges, thus determining vertical slots 27 that enable the formation of individual folds in the tubular material 2 that wraps around them during production of the bags.

[0083] In FIG. 6, in which the lower expansion body 4b has been deprived of one of its plates, an introducer 37 is shown comprising two fingers 37a, which penetrate through the vertical slots 27 from the outside into the lower expansion body 4b, gradually, in the forward direction of the tubular material during the production process of the bags. This introducer 37 enables the tubular material to be folded inwardly, preparing it for the transverse welding that will form the closed bottom of the bag.

[0084] FIGS. 4 to 6 show schematically a sealing and cutting device 39, which produces the bottom of the bags. This sealing and cutting device 39 is in itself known and is not described in greater detail because it is not an essential part of the invention.

[0085] A preferred characteristic of the plates 35 and 36 is shown in FIG. 4. Specifically, it shows that they have a window into which a cover 29 is placed, the outer surface of which is a covering material that provides non-stick properties, highly resistant to heat, suitable for serving as a welding back for the welding plates 22 and 23. This covering material may be made of, for example, polytetrafluoroethylene (PTFE).