INDUSTRIAL PAPER SACK OF THE VALVE TYPE

Abstract

An industrial paper sack of the valve type, includes a tubular side wall extending along a longitudinal axis, a first bottom arranged on one side of the tubular side wall along a direction parallel to the longitudinal axis and a second bottom arranged on an opposite side with respect to the first bottom along the direction parallel to the longitudinal axis. The first bottom includes a filling opening of the sack, configured to be sealed after the filling of the sack. The second bottom is folded at a first folding line to form a first folded bottom portion and includes, at a free end of the first folded bottom portion, an emptying opening of the sack. The first folded bottom portion is coupled to the tubular side wall by a removable coupling device.

Claims

1. An industrial paper sack of a valve type, comprising a tubular side wall extending along a longitudinal axis, a first bottom arranged on one side of the tubular side wall along a direction parallel to the longitudinal axis and a second bottom arranged on an opposite side with respect to the first bottom along said direction parallel to the longitudinal axis, wherein the first bottom comprises a filling opening of the sack configured to be sealed after the filling of the sack and wherein the second bottom is folded at a first folding line to form a first folded bottom portion and comprises, at a free end of said first folded bottom portion, an emptying opening of the sack, wherein said first folded bottom portion is coupled to said tubular side wall through a removable coupling device.

2. The sack according to claim 1, wherein the second bottom is further folded at a second folding line to form a second folded bottom portion, said second folded bottom portion being connected to said first folded bottom portion at said first folding line and wherein said removable coupling device is active between said second folded bottom portion and said tubular side wall.

3. The sack according to claim 2, wherein said removable coupling device is formed on a patch associated with said second folded bottom portion and with said tubular side wall.

4. The sack according to claim 3, wherein said patch is glued to said second folded bottom portion and to said tubular side wall.

5. The sack according to claim 1, wherein said removable coupling device comprises a tear tab.

6. The sack according to claim 5, wherein said removable coupling device is formed on a patch associated with said second folded bottom portion and with said tubular side wall, and wherein said tear tab is overlapped to said first fold line and, when it is torn, separates said patch in two opposite portions, one of the two opposite portions remains associated with said second folded bottom portion and the other one of the two opposite portions remains associated with said tubular side wall.

7. The sack according to claim 1, wherein said first folding line is substantially orthogonal to the longitudinal axis.

8. The sack according to claim 1, wherein the second bottom is further folded at a second folding line to form a second folded bottom portion, said second folded bottom portion being connected to said first folded bottom portion at said first folding line and wherein said removable coupling device is active between said second folded bottom portion and said tubular side wall, and wherein said second folding line is substantially orthogonal to the longitudinal axis.

9. The sack according to claim 1, comprising a front face and a rear face mutually glued at two end portions of the second bottom, said end portions being arranged on opposite sides with respect to the longitudinal axis.

10. The sack according to claim 1, wherein said filling opening is sealed by thermal or ultrasonic welding.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Further characteristics and advantages of the present invention will become clearer from the following detailed description of preferred embodiments thereof, made with reference to the appended drawings and provided by way of indicative and non-limiting example. In such drawings:

[0044] FIG. 1 is a plan view of an industrial paper sack of the valve type in accordance with the present invention in a first operating configuration thereof (sack closed with removable coupling device not removed);

[0045] FIG. 2 is a plan view of the sack of FIG. 1 in a second operating configuration thereof (sack closed with removable coupling device removed);

[0046] FIG. 3 is a plan view of the sack of FIG. 1 in a third operating configuration thereof (partially unfolded sack);

[0047] FIG. 4 is a plan view of the sack of FIG. 1 in a fourth operating configuration thereof (fully unfolded sack).

DETAILED DESCRIPTION

[0048] In FIGS. 1-4, an industrial paper sack of the valve type in accordance with the present invention is indicated with reference numeral 10.

[0049] The sack 10 comprises a tubular side wall 20 extending along a longitudinal axis X.

[0050] A first bottom 30 and a second bottom 40 are formed on opposite sides of the tubular side wall 20 with respect to a direction parallel to the longitudinal axis X.

[0051] In FIGS. 1-4 the sack 10 is shown when it is empty, i.e., when it has not yet been filled. The filling material may be of different type, for example flour if the sack 10 is intended for use in the food field, granules of plastic material if the sack 10 is intended for use in the chemical field, cement if the sack 10 is intended for use in the construction field, seeds if the sack 10 is intended for use in the agricultural field, feeds if the sack 10 is intended for use in the zootechnical field, etc.

[0052] In FIGS. 1-4 the sack 10 is shown in a flattened configuration thereof.

[0053] The sack 10 comprises a front face 11 and a rear face, wherein the term “front” is used to refer to the visible face of FIGS. 1-4 and the term “rear” is used to refer to the hidden face in FIGS. 1-4.

[0054] The tubular side wall 20 is formed starting from a sheet of paper, or from a plurality of overlapped layers of paper, which is/are wrapped around the longitudinal axis X to form a tubular structure. The tubular side wall 20 is joined at a gluing line 22 extending along a direction substantially parallel to the longitudinal axis X. In the case of several overlapped layers, different gluing lines may be provided for each layer, the gluing lines possibly being staggered with respect to each other.

[0055] In the non-limiting example shown in FIGS. 1-4, the gluing line 22 is provided on the rear side of the sack 10.

[0056] In the case of multiple overlapped layers, they are connected to each other (e.g., glued) at respective joining portions. A layer made of plastic material may also be provided, such a layer being overlapped on one or more layers of paper and being arranged internally to a layer of paper or interposed between two layers of paper. The layer of plastic material may also be more than one, in which case each of them is interposed between two respective layers of paper.

[0057] The first bottom 30 is formed by conveniently folding a first end portion 30a of the sack 10 and by applying, for example by gluing, a first patch 33 to the folded end portion 30a, the first patch 33 being preferably made of paper. In the non-limiting example of FIGS. 1-4, the first patch 33 has a rectangular shape.

[0058] The first patch 33 actually provides the first bottom 30 with a flattened and sufficiently stiff shape, suitable to allow the sack 10 to stand when filled and resting on the ground or on a horizontal plane at the first bottom 30.

[0059] The first bottom 30 comprises a filling opening 32 of the sack 10, which defines the so-called valve of the sack 10 and which is configured to be sealed after the filling of the sack 10.

[0060] The sealing takes place by thermal welding (in this case, the valve is called “heat-sealing valve”) or ultrasonic welding.

[0061] To allow sealing, a coating layer 34, preferably made of plastic material, is placed inside the sack 10 around the filling opening 32.

[0062] In particular, the coating layer is glued to a layer of paper arranged around the filling opening 32.

[0063] The second bottom 40 comprises an emptying opening 42 of the sack 10 (FIG. 4). The emptying opening 42 is substantially orthogonal to the longitudinal axis X.

[0064] The second bottom 40 is folded at a first folding line 44 so as to form a first folded bottom portion 43 (FIG. 3), and subsequently the first folded bottom portion 43 is folded at a second folding line 46 so as to form a second folded bottom portion 45 (FIGS. 1 and 2).

[0065] The first folding line 44 is substantially orthogonal to the longitudinal axis X and thus substantially parallel to the emptying opening 42.

[0066] The first folding line 44 is arranged at a predetermined distance A from the emptying opening 42 (FIG. 4).

[0067] The first folded bottom portion 43 is defined between the first folding line 44 and the emptying opening 42 (FIG. 3).

[0068] The emptying opening 42 is defined at a free end of the first folded bottom portion 43, which corresponds to a free end of the sack 10 in its initial shape, before forming the second bottom 40 (FIG. 4).

[0069] The second folding line 46 is substantially orthogonal to the longitudinal axis X and thus substantially parallel to the first folding line 44.

[0070] The second folding line 46 is arranged at a predetermined distance B from the first folding line 44 (FIGS. 3 and 4).

[0071] The second folded bottom portion 45 is defined between the first folding line 44 and the second folding line 46 (FIGS. 1 and 2). The second folded bottom portion 45 is connected to the first folded bottom portion 43 at the first folding line 44.

[0072] The distance A is less than or equal to the distance B.

[0073] The second bottom 40 comprises a removable coupling device 48 configured to couple the second folded bottom portion 45, or the first folded bottom portion 43 in cases where the second folding is not provided at the second folding line 46, to the tubular side wall 20.

[0074] The removable coupling device 48 is formed on a second patch 50 associated with the second bottom 40, in particular with the second folded bottom portion 45, and with the tubular side wall 20.

[0075] The removable coupling device 48 comprises a tear tab 52 overlapped on the first folding line 44 and on the tubular side wall portion 20 adjacent to the first folded bottom portion 43, when the first folded bottom portion 43 is folded like in FIGS. 1 and 2.

[0076] The tear tab 52 has an end portion 53 adapted to be grasped by the user to lift it and tear it away from the second patch 50. The end portion 53 is indicated for example by a line drawn on the second patch 50 so that it is immediately identified by the user.

[0077] When the tear tab 52 is torn (FIG. 2), it separates the second patch 50 in two opposite portions 50a and 50b. The portion 50a is adjacent, on the one hand, to the first folding line 44 and, on the other hand, to the second folding line 46. The portion 50a remains associated with the second folded bottom portion 45, while the portion 50b remains associated with the tubular side wall 20.

[0078] In the embodiment shown in the attached figures, the second patch 50 has slightly smaller dimensions than those of the second bottom 40. The second patch 50 is preferably made of paper and is glued to the second bottom 40.

[0079] In other embodiments, not shown, the second patch 50 may have substantially the same or slightly larger dimensions than those of the second bottom 40 and/or of the tubular side wall 20.

[0080] In the non-limiting example of FIG. 1, the second bottom 40 and the second patch 50 are rectangular in shape. In particular, the second patch 50 has a width slightly smaller than that of the second bottom 40.

[0081] In order to provide the filled sack 10 with a stiffer and more defined shape, the front face 11 can be glued to the rear face of the sack 10 at two end portions 24 of the second bottom 40. Such end portions 24 are arranged on opposite sides with respect to the longitudinal axis X.

[0082] Only after removing the tear tab 52 and unfolding the second bottom 40 around the two folding lines 44 and 46 one can access to the material contained in the sack 10 and the removal of said material from the sack 10 can take place through the emptying opening 42.

[0083] The sack 10 is not damaged following the removal of the tear tab 52 and it is possible, for example, to close it by folding the second bottom 40 at the folding lines 44 and 46 and possibly by applying a new patch 50.

[0084] Obviously, in order to meet specific and contingent needs, a person skilled in the art may make numerous modifications and changes to the sack described above, all of which are within the scope of protection of the present invention as defined by the following claims.

[0085] For example, only one folding line could be provided instead of the two folding lines 44, 46 of the non-limiting example of FIGS. 1-4.

[0086] Or, more than two folding lines could also be provided.

[0087] The folded bottom portions 43, 45 of the second bottom 40 may be glued to each other before emptying the sack 10. This arrangement can also be provided in the case of the non-limiting example of FIGS. 1-4.

[0088] The patches 33 and 50 may extend only on the front side or only on the rear side or on both sides of the sack 10. In the non-limiting example of FIGS. 1-4, the patches 22 and 50 extend only on the front side of the sack 10.