METHOD FOR CLOSING A FILTER BAG FOR INFUSIBLE PRODUCTS AND FOR CONNECTING A TAGGED THREAD THERETO

Abstract: A single-dose filter bag for infusible products (1) is closed by folding a flap (30) made in the upper part of the filter bag (1) and a thread (10) is attached thereto directly by a terminal portion of the thread or indirectly by auxiliary threads (31, 41).

Description: METHOD FOR CLOSING A FILTER BAG FOR INFUSIBLE PRO¬ DUCTS AND FOR CONNECTING A TAGGED THREAD THERETO TECHNICAL FIELD The present invention relates to a filter bag for infusible products, particularly for single-dose packages of tea, extracted beverages and the like. BACKGROUND ART It is known that for the preparation of hot infusions, there are commonly used single-dose portions of ground product, closed in a filter bag, that is soaked at the time of consumption of the infusion in a suitable container with boiling water. These filter bags may have different struc- tures, according to the solutions found in order to improve the ground product expansion after it has been dipped in water, so as to allow its best disso¬ lution. The most common structures are obtained from a sheet of filter paper, suitably folded after the ground product has been put thereonto, and then closed so as to prevent the ground product from going out. Most common filter bags feature one or more sections or lobes for containing the ground product, with or without the side bellow-like folds. This filter bag is closed either by thermo- welding, if it is made of thermoweldable filter paper, or by gluing different outer edges of the filter bag, or using a metallic clip blocking the said edges. One end of a cotton thread is fixed to the filter bag, while the other end of the thread bears a tag forming the pick-up element for handling the filter bag when introduced in or withdrawn from boiling water. The thread is usually fixed to the filter bag by gluing or using a metallic clip, or by applica¬ tion of a label made of thermoweldable material that connects the thread with the upper edge of the filter bag. Also the other end of the thread can be fixed to the tag by gluing or using a metallic clip. For filter bags produced with thermoweldable filter paper, artificially obtained or, anyway, treated materials are used. These materials, when in contact with boiling water, could release sub¬ stances which can change the infusion organoleptic features. The metallic clip is preferably used for closing filter bags (and fixing the tagged thread) made of natural fibres, that cannot be thermally welded. Also in this embodiment, the metallic clip, when in contact with boiling water and subsequently with the extracted beverage, could contaminate the infusion. The object of the present invention is to provide a single-dose filter bag for infusible products, and a new method for closing the same and fixing a pick-up tagged thread thereto, without using materials harmful to health. Accordingly, elements that sometimes could appear not quite safe, like metallic clips, are not used, since they can contaminate the infusion. DISCLOSURE OF THE INVENTION The above mentioned object is obtained, in accordance with the contents of claims, by means of a method for closing a filter bag for infusible pro¬ ducts, and for connecting a tagged thread to the said filter bag, the said filter bag including at least a lobe and at least a flap folded to prevent the filter bag from opening and the infusible pro- duct from going out, a pick-up tag and a connecting thread, the said method being characterised in that in that it includes fixing means for locking the said flap in a pre-determined position and simultan¬ eously fixing a free first terminal portion of the said thread to the said filter bag, the said termi¬ nal portion being defined at an end of the said thread other than the end where a second terminal portion is defined, and destined to be fixed to the said pick-up tag. BRIEF DESCRIPTION OF THE DRAWINGS The characteristic features of the present invention are pointed out in the following descrip¬ tion with reference to the enclosed drawings, in which: - figures from 1 to 4 show manufacturing of a known filter bag according to conventional methods; - figures 5a and 5b show a first embodiment of the method for closing the filter bag and simultaneously fixing a thread bearing at its other end a pick-up tag; - figures 6a and 6b show a second embodiment of this method; - figures 7a and 7b show a third embodiment of the aforementioned method; - figures 8a and 8b show a fourth embodiment of the proposed method; - figure 9a shows the preferred embodiment of the method for fixing the thread to the filter bag and, in combination, to the respective pick-up tag, with the filter bag in use; - figures 9b, 9c show other versions of the said method; - figure 10 shows a preferred way of folding the connecting thread around the filter bag, and of fixing the same to the pick-up tag, with reference to the combination of figure 9a; - figures 11a to 11m show schematically working steps of the method for closing the bag, as in figures 8b, 9a, and of the method for fixing the tag to the connecting thread, as in figure 9c; - figure 12 shows a sectional view, taken along the line XII-XII of figure Hi with some parts removed in order to disclose others. BEST MODES OF CARRYING OUT THE INVENTION With reference to figures 1 to 4, a filter bag 1 has e.g. two lobes, respectively first la and second lb, suitably folded so as to face each other and form an upper edge 2 (figure 2) . Each lobe of the filter bag 1, that is not shown in the initial step when unfolded, is firstly filled with one dose of ground product for infusion 7, and then the filter bag is closed longitudinally by a multiple mutual folding and pressing of the outer edges lc. it will be understood that the double lobe configuration of the filter bag 1 is not limitative, but helps the description of some preferred embodi¬ ments of the present invention; therefore, it is clear that what described in the following, is applicable to different structures of the filter bag 1, e.g. the one with a single lobe. In order to prevent the ground product 7 from going out of the filter bag 1, a flap 30 is defined by a fold 3 (figure 4) e.g. formed by simple fold¬ ings, respectively first 4, second 6 and third 8, made one after the other at the upper edge 2. Fixing means 100, that carry out the proposed method, fasten the flap 30 in a predetermined posi¬ tion, close the filter bag, and, at the same time, fix a free first terminal portion 11 of the thread 10 thereto. The filter bag 1 includes also a pick-up tag 13, fixed thereto by means of a thread 10, usually made of cotton. The tag 13 facilitates insertion of the filter bag 1 into the boiling water and its subse¬ quent withdrawal during infusion preparation. This pick-up tag 13 is fixed to a second terminal portion 12 of the thread 10 opposite to the first terminal portion 11. in a first embodiment of the present inven¬ tion, shown in figures 5a and 5b, the said fixing means 100 are formed by the same free first termi¬ nal portion 11 of the thread 10, knotted in corre¬ spondence with the flap 30. The thread 10 is fastened by introduction of two subsequent parts 11a, lib of the free first terminal portion 11, forming a loop, into a hole 60 made in the flap 30, and by subsequent introduction of a final part lie of the first terminal portion 11 into the loop. Then, the loop is closed so as to lock the final section lie preventing it from releasing. In a second embodiment, shown in figures 6a and 6b, the fixing means 100 are formed by a first auxiliary thread 31, usually made of cotton or other similar natural fibre. The thread 31 fastens the flap 30 and, at the same time, connects the thread 10 to the filter bag 1 by a vertical stitch, e.g. chain stitch 130. The chain stitch 130 sews also two adjacent sections 11a, lib of the free first terminal portion 11, arranged vertically on opposite sides of the flap 30. The two sections 11a, lib rest on two oppo¬ site sides of the flap 30, passing over the horizon- tal flap line 8b (figure 6a) , and then are sewn by the stitch 130 using the auxiliary thread 31. In a third embodiment, shown in figures 7a and 7b, the said fixing means 100 are formed by a second auxiliary thread 41. made of cotton or another natural fibre. In this embodiment, a straight, e.g. horizon¬ tal, stitch 40, performed along the flap 30, closes the flap 30 and fastens the free first terminal portion 11, sewing the adjacent sections 11a, lib thereof, arranged vertically on the opposite sides of the flap. As in the precedent embodiment, the two adjacent sections 11a, lib are placed on the oppo¬ site sides of the flap 30 (figure 7a) , and then are sewn, by known and not illustrated sewing means, by the straight stitch 40 using the second auxiliary thread 41 (figure 7b) . In a fourth embodiment, shown in figures 8a, 8b, the fixing means 100 are constituted by the same first terminal part 11, the terminal part lie of which is used to perform, by known sewing means, like e.g. shown in figures 11 and 12, a stitch 50 along the flap 30, as shown in figures 11 and de¬ scribed in the following. In the first three embodiments, the first terminal portion 11 of the thread 10 is turned around the flap 30. The second terminal portion 12 of the thread 10 can be fastened to the pick-up tag 13 by sewing, preferably by a vertical sewing described in the second embodiment of the present method, or by a stitch forming a kind of a knot, as described in the fourth embodiment. In the first case, a third auxiliary thread 71 is used (figures 9a, 9b) , designed to sew, with the vertical stitch 70, two adjacent sections 12a, 12b of the second terminal portion 12 of the thread 10, arranged vertically on the opposite sides of the tag 13 and turning around the upper edge thereof. In the second case, (figure 9c) , a stitch 60, performed in the same way as the stitch 50, allow the terminal part 12 to be fastened to the tag 13. A slit 14, substantially directed according to the major axis of the pick-up tag 13, is made in correspondence with the lower edge thereof (see figure 10) . The slit 14 is destined to allow the tag and the thread 10 to be fastened to the filter bag 1, by winding vertically the said thread 10 around the filter bag 1, until the tag 13 is placed on the flap 30. A part of the thread 10, correspondent to the slit 14, is then introduced therein and kept there by friction and elastic reaction. The working steps to perform the stitches 50, 60 are shown in figures from 11a to 11m. In connection with the figures, the reference number 200 indicates the material (that is the flap 30 and the adjacent head of the filter bag 1, or tag 13), on which the stitch 50, 60 is made. On one side of the material 200, there is a needle 201, provided with a thread 202, made to oscillate between two extreme working positions XI, X2, while on the other side there are positioned two rotating hooks, or looper 203, 204, that oscillate in a suitable time relation with respect to the relative axes 203a, 204a parallel one to the other. In particular, the working positions XI, X2 are symmetrical with respect to a vertical plane, and the axes 203a, 204a are, with reference to the figures from 11a to 11m, respectively on the right and on the left of this plane, therefore, the re¬ spective loopers 203, 204 will be indicated respect¬ ively as right looper and left looper, and the said working positions XI, X2 are indicated, with refer¬ ence to the said plane, as right and left positions. In the figure 11a, the needle 201, in the right position XI, is outside the material. The needle 201 translates in the direction F, in syn¬ chrony with clockwise rotation K of the two loopers (with reference to the figures) , passes through the material, thus making therein a hole 205 (figure lib) . When the needle goes up, a loop Cl is formed in the part of the thread connected with the needle and it is hooked by the left looper 204 (figure lie) rotating in the said direction K. When the needle has turned up, it is brought to the left position X2 (figure lid) . The subsequent descent of the needle is in time relation with the oscillation of the two loopers in counterclockwise direction W (figure He) . The needle 202 is introduced in the loop Cl, hooked by the left looper 204, before the latter (said looper 204) has been released from the same loop (figure He) . The loop Cl, already released from the left looper, becomes gradually smaller, because, during the needle descent, the part of the loop, connected with the section of the thread adjacent to the needle, is pulled, thus making the same section slide from the hole 205 to the new hole 206 made in the material 200 by the needle placed in the left position X2: all this is illustrated in figures llf, llg and llh, in which the loop is deliberately loose in order to point it out. Raising of the needle situated in the left position X2, makes a new loop (or second loop) C2 that is hooked by the right looper 203 (figure llg) , rotating in the counterclockwise direction W. In the figure llh the needle 201 is shown in the raised position and again in the right position χi; this figure points out that the loop Cl tightens the thread portions that go out from the hole 206 and extends so as to form the second loop C2, hooked by the right looper 203. The working cycle described in figures from iia to llh, is usually repeated for a predetermined number of times, obviously using again the holes 205, 206. It has been found that two or three cycles are sufficient for the stitch 50, 60 to be made in best way. At the end of the predetermined number of cycles, with the second loop C2 hooked by the right looper 203, a needle cutting device is activated, constituted by a circular arm, which fork-like head 208 intercepts a branch PI of the loop C2 in order to cut it in cooperation with a cutting blade 209 situated on the back of the right looper. The remaining part P2 of the second loop C2 is withdrawn from the hole 206 and, subsequently, it is made translate in direction Y (figure 11m) . The so obtained stitch 50, 60, has a shape that satisfies all its provided functions, in par¬ ticular closes the filter bag (figures 8b, 9a) and fixes the tag 13 to the thread 10. The stitch 50, 60 is defined by a portion of thread that passes through the hole 205, beginning from a surface of the material 200, forms a loop in correspondence with the other surface, passes again through the hole 205, then crosses the adjacent surface of the material, passes through the hole 206 and the loop, the whole is tightened so as to be firmly connected with the material 200. The conformation described above can be repeated, using the same holes, in order to improve the connection of the stitch to the material 200. The present invention allows to obtain filter bags for infusible products exclusively of natural fibres, therefore, not harmful to health of infusion consumers. At this point, it is particularly advantag¬ eous, to avoid filter paper made of thermoweldable materials for manufacturing filter bags. Anyway, this possibility is not limitative, since according to the present invention, the filter bags can be made also of these thermoweldable mater¬ ials or others, not described. It is also to be pointed out that, in the first embodiment of the present invention, the free first terminal portion 11 can be connected to the filter bag 1 also by other types of knot, other than the one illustrated.

Claims: CLAIMS 1. Method for closing a filter bag for infusible products, and for connecting a tagged thread to the said filter bag, the said filter bag including at least a lobe (la,lb) and at least a flap (30) folded to prevent the filter bag (1) from opening and the infusible product (7) from going out, a pick-up tag (13) and a connecting thread (10) , the said method being characterised in that in that it includes fixing means (100) for locking the said flap (30) in a pre-determined position and simultaneously fixing a free first terminal portion (11) of the said thread (10) to the said filter bag, the said termi- nal portion being defined at an end of the said thread other than the end where a second terminal portion (12) is defined, and destined to be fixed to the said pick-up tag. 2. Method as in claim 1, characterised in that the said fixing means (100) include the said free first terminal portion (11) of the said thread (10) , connected to the said filter bag in a region of the said flap (30) , by means of a knot. 3. Method as in claim 1, characterised in that the said fixing means (100) include a first auxiliary thread (31) that locks the said flap (30) and fixes the said free first terminal portion (11) of the said thread (10) by means of a vertical stitch (130) that engages adjacent sections (Ha,lib) of the said free first terminal portion (11) situated on opposed sides of the said flap (30) , and in that fixing of the said thread (10) to the said pick-up tag (13) is obtained by means of a third auxiliary thread (71) used to make a further vertical stitch (70) that engages adjacent sections (12a,12b) of the said second terminal portion (12) which are arranged vertical on opposed sides of the said tag (13) , close to the upper edge thereof. 4. Method as in claim 1, characterised in that the said fixing means (100) include a second auxiliary thread (41) that locks the said flap (30) and fixes the said free first terminal portion (11) of the said thread (10) by means of a straight stitch (40) that engages adjacent sections (Ha,lib) of the said free first terminal portion (11) , with the said adjacent sections (Ha,lib) located on opposed sides of the said flap (30) . 5. Method as in claim 1, characterised in that the said fixing means (100) include the said free first terminal portion (11) of the said thread (10) , the said first terminal portion (11) being fastened to the said filter bag, in a region corresponding to the said flap (30) , by means of a first stitch (50) made using a final section (He) of the same free first terminal portion (11) , and in that the said thread (10) is fastened to the said tag (13) by means of a third auxiliary thread (71) that is used to make a vertical stitch (70) to engage adjacent sections (12a,12b) of the said second terminal portion (12) which are situated on opposed sides of the said tag (13) , close to an upper edge of the same tag, and which turn around the same tag. 6. Method as in claim 1, characterised in that the said thread (10) is fixed to the said pick-up tag 13 by means of a second stitch (60) made using the said second terminal portion (12) so as to obtain a kind of knot. 7. Method as in claim 5 or 6, characterised in that the said first stitch (50) and second stitch (60) form a kind of knot. 8. Method according to any of the claims 2 to 4, characterised in that the said free first terminal portion (11) of the thread (10) is arranged to turn around the said flap (30) . 9. Method as in claim 1, characterised in that the said pick-up tag (13) features a slit (14) situated at the lower edge thereof and parallel to the major axis of the same tag (13) , this slit being aimed at allowing to fasten together the said pick-up tag (13) , along with the thread (10) , and the filter bag (1) by winding the said thread around the filter bag (I) according to the symmetry axis of the said filter bag, so that the said tag is placed over the said flap (30) and over a section of the thread that is inserted in the said slit (14) . 10. Method as in claim 5, characterised in that the said first stitch (50) includes a terminal portion (II) of the said thread (10) , the said terminal portion (11) passing through a first hole (205) , made in the assembly formed by the said flap (30) and the upper head of the said filter bag (1) , from one side of the said assembly to the other side where it forms a loop by passing again through the said first hole (205) , crossing the adjacent surface of the said assembly, passing through a second hole (206) made in the said assembly, and lastly passing through the said loop, all this being then strongly tightened to firmly fix the flap (30) to the said filter bag and the said assembly to the said termi¬ nal portion (11) of the thread (10) . 11. Method as in claim 5, characterised in that the said second stitch (60) includes the said second terminal portion (12) of the said thread (10) , the said second terminal portion (12) passing through a first hole (205) , made in the said pick-up tag (13) , from one side of the said tag to the other side where it forms a loop by passing again through the said first hole (205) , crossing the adjacent surface of the said tag, passing through a second hole (206) made in the said tag, and lastly passing through the said loop, all this being then strongly tightened to firmly fix the said terminal portion (12) of the thread to the said tag.

Inventors: CARDINALI PAOLO, TAGLIAFFERI ROBERTO, CARDINALI, PAOLO, TAGLIAFFERI, ROBERTO
Applicants: CARDINALI PAOLO, IMA SPA, TAGLIAFFERI ROBERTO, CARDINALI, PAOLO, I.M.A. INDUSTRIA MACCHINE AUTOMATICHE S.P.A., TAGLIAFFERI, ROBERTO
Application year: 1995
Main classification: B65D81
IPC codes: B65B29, B65D81, B65D85