Method and apparatus for making infusion bags

Abstract: The packaging apparatus for bags (1) containing products for infusion envisages a plurality of stations (7, 9, 11, 14, 16, 18, 19, 20) located one after another along a feed line (A) and used first to continuously cut successive individual pieces of fabric (2) from a continuous strip (8) of fabric, then to transform the piece of fabric (2) from its flat configuration to a bag configuration, tubular in shape and with an open top which forms the mouth (4) and into which a dose (3) of product is inserted; the tubular bag is then moved to stations which cut the excess part of the mouth (4) to size and close the mouth by tying it with a continuous thread (5), so as to form a closed bag (1), containing a single dose of product and having a projecting upper portion of thread (5); finally, a label (6) is attached to the thread (5) on each bag (1) and the label is inserted in the bag (1) tying zone.

Description: The present invention relates to a packaging apparatus, in particular for making bags for products for infusion, such as tea, coffee, camomile, etc. The many types of bags used for the infusion of products such as tea, coffee or camomile (the best known having a single or double lobe shape), include some with a particular shape which do not comply with the typical shapes currently used, but use packaging materials and configurations which cannot be adapted to the normal automatic apparatus which make the above-mentioned conventional single or double lobe filter bags. The bags made by the apparatus which is the object of the present invention are of the "bundle" type, for example, as illustrated in patent GB - 450.703 and are made from a piece of fabric preferably loosely woven (e.g.: gauze) upon which a dose of product for infusion is deposited and which is closed in the piece of fabric by raising the sides of the fabric towards a single point, which forms the mouth of the bag, thus creating a bundle containing the dose of product. The mouth of the bag is closed by bringing together the free sides and firmly blocking them together in this position, using a metal ring or a knotted thread wound around the zone below, close to the point at which the free sides are brought together. If the sides are held together by a metal ring, as the ring and bag are put together, the end of a thread is attached to the ring, the opposite end of the thread being free and having a pick-up label zone, designed to allow the bag to be handled when immersed in a liquid to make the infusion. If the bag is tied with a thread, it is a portion of the same thread which extends for attachment to the free end of this portion of the pick-up label zone thread. In US-1 726 060, which is considered the closest prior art, is disclosed a method and an apparatus for packaging a commodity, and in particular tea, in a bag, in accordance with the preambles of claims 1 and 33. The apparatus comprises, among other stations, a station for the closure of the mouth of the bags. Said closure is made by raising a cage which encompasses the complete tea bag. A thread is wound around pins positioned in the upper part of the cage, then the cage is raised encompassing the bag. Then the loop is transferred on the bag and the thread is drawn in order to close the bag. In US-2 328 639 is disclosed another apparatus for packaging a commodity in a bag. The apparatus is an improvement of the apparatus of US-1 857 662 which is in turn based on the apparatus of US-1 726 060. The improvement relates to the mechanism for winding a string about the neck of the bag. The mechanism of US-2 328 639 comprises jaws for closing the bag. The jaws with the bag are continuosly rotated, whereby the bag is caused to spin rapidly causing the string to be wound tightly about the neck of the bag. Applicant has invented an apparatus for the production of bags for products for infusion of the above-mentioned type, that is to say, bundle shaped and with a thread closure, which is fully automated; bags are produced in extremely rapid cycles, with a high level of safety at all stages, and an overall reduction in costs. The technical features of the invention, in accordance with the afore-mentioned aims, are defined in the appended claims and the advantages of the invention are more clearly described below with reference to the accompanying drawings, which show a preferred embodiment of the invention, and in which: figure 1 illustrates a sequence of stages, labelled below with letters "a" to "i", for the manufacture of a bag designed to contain products for infusion, made using the packaging apparatus disclosed, all stages being illustrated in schematic perspective views; figures 2, 3 and 4 are respectively front, top plan and side views of the bag packaging apparatus shown in figure 1; figure 5 is a schematic side view of a station included in the apparatus shown in figures 2, 3 and 4, in particular a station which forms the bag and fills it with the product, with some parts cut away to better illustrate others; figure 5a is a schematic side view of a scaled-up detail of the station shown in figure 5, with some parts shown in cross-section and others cut away; figure 5b is a schematic top plan view of a scaled-up detail relative to figure 5a, with some parts cut away to better illustrate others; figure 6 is a partial top view of the forming and dosing station shown in figure 5, with some parts cut away to better illustrate others; figure 7 is a schematic top plan view of another two stations on the above-mentioned apparatus shown in figures 2, 3 and 4, in particular a bag pick-up and transfer station and a station for application of a bag tying thread, with some parts cut away to better illustrate others; figures 8 and 9 illustrate the tying station shown in figure 7, respectively from points C and D in figure 7; figure 10 shows a series of stages, labelled below with letters "a" to "h", envisaged for tying the bag as it transits through the station shown in figures 7, 8 and 9, all of the sub-stages being shown in schematic top plan views; figure 11 shows part of the stages shown in figure 10, labelled below with the corresponding letters in figure 10, that is to say "c", "d", "f" and "g", in which part of the bag and the relative tying rings made on it are visible; all stages being shown in a partial perspective view of the bag; figure 12 shows other stations on the apparatus shown in figures 2, 3 and 4, in particular a station for application of a label to a thread attached to the bag and a station which attaches the label to the bag; figure 13 is a formation diagram of a bag made using the apparatus disclosed, in particular the theoretical production of the same bag as shown at the station in figures 7, 8 and 9; figure 14 is a schematic front view of a station on the apparatus disclosed, in particular a station for cutting the part of the bag that is not tied, with some parts cut away to better illustrate others; figure 15 is a schematic front view of part of the apparatus disclosed, inherent to a zone of intersection of two carousels which transfer the bag between the various operating stations, with some parts cut away to better illustrate others; figure 16 shows a detail illustrated in figure 15, more precisely second grippers, as seen from point R in figure 15; figure 17 is a front view of part of a station on the apparatus in which the final configuration of the bag is defined, with some parts cut away to better illustrate others; figure 18 is a perspective view of the tying station illustrated in figures 7, 8 and 9, with some parts cut away; figures 19, 20 and 21 are front views of the respective stages involved in depositing a ring on the bag by the station shown in figures 7, 8, 9 and 18, with some parts shown in cross-section; figure 22 is a schematic side view of another embodiment of several technical details of the tying station shown in figure 18, with some parts cut away to better illustrate others; figure 23 is a scaled-up schematic perspective view of a support surface which is part of the first carousel shown in figure 7; figure 24 is a schematic front view from point V1 relative to figure 23, with some parts cut away to better illustrate others. In accordance with the accompanying drawings, and in particular with reference to figure 1, the packaging apparatus disclosed is designed to produce bags 1 for products for infusion, such as tea, coffee, camomile, etc. In particular, these bags 1 each consist of a piece 2 of fabric, preferably loosely woven (for example, gauze), although other types of weave are not excluded. A dose 3 of the above-mentioned product is deposited in the bag formed from a piece of the fabric 2; the dose 3 is closed inside the fabric by folding the sides of the fabric 2 over until the free edges are brought together at a given point to form the mouth 4 of the bag, at which a tying thread 5, wound around the bag to close it is envisaged. A label 6 is attached to the opposite, free end of the thread 5, the label designed to support and allow handling of the bag 1 when making the infusion. The apparatus disclosed, in particular see figures 2, 3 and 4, mainly consists of a plurality of stations, divided into eight to facilitate the description, some of which (more clearly illustrated below), incorporate two or more elements for the production of the above-mentioned bag 1. In the following text, most of the operating elements described have a "stepping" movement, with the pauses necessary to carry out the operations required for bag production. These eight stations are located one after another along a feed line A and are described according to the operating "chronology" for bag 1 production. The first station, labelled 7, allows the feed of a continuous strip 8 of the above-mentioned woven fabric towards a second station 9. The continuous strip 8 (see figure 2) is fed from a reel 77 by means of a motor driven pre-unwinding unit 78a, and a subsequent stepping unwinding unit 78, both of known types. The reel 77 is located upstream of the second station 9 relative to the direction of feed A. The stepping unit 78 allows the continuous strip 8 of fabric to arrive at the second station 9; this is equipped with a transverse cutting unit 10 for the strip 8, designed to cut a series of flat (see figure 1b) pieces 2 of fabric. The cutting unit 10 is not fully illustrated, being of the known type and consisting of, for example, a transverse blade 79 radially supported by a roller 80. The flat piece of fabric 2 is transferred to a third station 11 (see also figures 5 and 6) equipped with generic means 12 which transform the flat piece of fabric 2 to the bag configuration, that is to say, tubular in shape, with an open top which forms the above-mentioned mouth 4. In addition, the third station 11 comprises means 13 which feed a dose 3 of product into the bag formed in this way. More precisely, again see figures 5 and 6, the above-mentioned means 12 for formation of the fabric bag consist of an open tubular element 25, positioned vertically relative to the feed line A; this tubular element 25 is supported and moved by the end of a horizontal arm 26 attached to a support structure 27 on the apparatus. This arm 26 moves (see arrow F4 in figure 5) between two end positions: towards the support structure 27 (shown as a continuous line in figure 5) and away from the structure (shown as a dashed line in figure 5), the reason for this movement being described below. With reference to the schematic figure 5a, the tubular element 25 moves vertically relative to a fixed internal element 25g, between two end positions illustrated in figure 5a, the upper shown as a dashed line and the lower as a continuous line. During its operative downstroke, the tubular element intercepts the initially flat piece of fabric 2, deforming it so that it takes on a bag shape, as shown, with the edges 2b resting on a contrast and sliding surface 25p. A hole 25f for "drawing" the piece of fabric 2 is also present in this surface 25p. Following this stage, holding means 25r act upon the portion of the bag near to the lower part of the surface 25p, labelled 2c, holding the bag in the configuration shown in figure 5a during the subsequent operation for insertion of the dose 3; these means 25r preferably consist of grippers which make contact with the exterior of the tubular element 25 (also shown in schematic figure 5b). The dose 3 is inserted by a presser or ejector 28 coaxial to the tubular element 25. This presser 28, including an end pad 81 which is integral with a vertical rod 82, is moved by relative means 29, towards (and respectively away from) the bag 2s (see arrow F2 in figures 5 and 5a), inserting the dose 3 in the bag. The above-mentioned drive means 29 are shown in figure 5 as a mechanism consisting of a lever 83 attached to the rod 82 and in turn connected to relative drive means (not illustrated here, being of the known type) which allow the presser 28 to be raised and lowered. The above-mentioned dose 3 feed means 13 consist of a product feed hopper 30, positioned above a product holder and dosing drum 31. This drum 31 (revolver shaped) can rotate about its vertical axis Z3 (see arrow F3 in figure 6), and has a plurality of through-holes 33 (each forming a product dosing compartment), evenly distributed over the circumference of the drum 31, whose lower section is closed by a base 32 which has a single hole 32f, for the passage and discharge of the dose at the presser 28 vertical position. The drum 31 is also operated upon by means 34 designed to allow even product distribution as the product drops into the holes 33. These means 34 preferably consist of a plurality of mixing blades 35 which rotate above the drum 31 about the vertical axis Z3, that is to say, integral with a shaft that is positioned coaxial to the drum support shaft 36. Returning to the support arm 26 for the tubular element 25, as already indicated, the arm moves between the above-mentioned end positions, the vertical movement being driven by a mechanism consisting of a vertical pin 26a which supports the arm 26, the pin 26a being connected to and moved by a lever mechanism 26b connected to drive means which are not illustrated. When the tubular element 25 is moved away from the bag 2s, that is to say, when it returns to the raised position (shown as a dashed line in figure 5a), the bag remains substantially suspended in the gripper means 25r, with the dose 3 inside it, in a position which allows the bag 2s to be picked up by first bag pick-up means 15; more precisely, the gripper means 25r carry out pre-closing of the mouth 4 of the bag 1 in such a way that they do not prevent subsequent bag pick-up, during which the bag is drawn by the above-mentioned first means 15, as shown in figure 5b, in which the bag is drawn in the direction labelled SF. The bag, complete with dose 3, is hereinafter labelled 1. As shown in figures 3, 7 and 12, the first pick-up means 15 are part of a fourth, transfer station 14, designed to transfer each bag 1 to the subsequent stations located near and along the path of the fourth station: in order to carry out the relative operations required to close the bag which has just been configured. More precisely, this fourth station 14 consists of a first carousel 38 with vertical axis of rotation Z and a plurality of operating zones 39 evenly distributed over the external circumference of the first carousel 38. Each operating zone 39 may comprise grippers 40 which grip the portion of the bag 1 below the mouth 4, therefore forming the above-mentioned pick-up means 15, and a surface 41, on a plane above the grippers 40, the surfaces 41 being alternated with the grippers. Each surface 41 has a seat 42 for housing a relative label (described more clearly below), vertical pins 42p being envisaged at the side of the seat and, as described below, holding a continuous thread 5, used to join the bag 1 and label 6, defining half an arc which copies the external circumference of the first carousel 38 as it moves forward and towards the subsequent stations. As shown in figures 7, 12, 14, 15 and 18, each of the grippers 40 consists of a body 40a with a pair of jaws 40b, 40c which can rotate about the vertical axis 40Z of the body 40a. The jaws 40b, 40c are shaped in such a way that, when turned in the closing configuration (this position clearly shown in figures 7, 12 and 18), they form a complementary seat 40s to support and house the part of the mouth 4 not affected by the closing operations described below. Again observing figure 3, the numeral 16 is used to label a fifth station equipped with means 17 for cutting a predetermined part of the upper end of the tubular bag 1, that is to say, part of the mouth 4 located above and not touched by the pick-up grippers 40. As is also visible in figures 1d and 14, the fifth station 16 may consist of one or two blades 43, supported by a relative structure located near the fourth station 14. This blade 43 moves, see arrow F43, between a forward, operating position, in which the blade 43 intercepts the portion of the bag 1 which forms the mouth 4 at a given predetermined height H relative to the grippers 40, and a retracted, home position, shown with a continuous line in figure 14. As schematically illustrated in figure 14, to obtain a correct cut which is suited to the subsequent closing operations (described in more detail below), the free end of the mouth 4 is closed, during the cutting stage, to form as cylindrical a portion as possible, by a pair of jaws 16g which move above the grippers 40. These jaws 16g move between two end positions (see arrows F16), respectively the idle position (shown as a dashed line in figure 14), in which the jaws are moved away from one another and from the mouth 4, and an operating position, in which the jaws 16g are brought together and clamp the part above the mouth 4 (shown as a continuous line in figure 14). Therefore, in the operating position, the jaws 16g clamp the end of the mouth 4, holding it vertical to contrast the cutting stage. An ejection unit for the waste cut is preferably located above the jaws 16g; this unit may consist of a vacuum duct 16c. In figures 3, 4, 7, 8, 9 and 18, the numeral 18 is used to label a sixth station, located downstream of the previous fifth, cutting station 16 on the feed line A. This sixth station 18 allows the winding and relative closing by tying off of the remaining end of the mouth 4 of the tubular fabric bag with a continuous thread 5, so as to form a closed bag 1, containing a single dose and with a projecting portion of thread 5. More specifically, the sixth station 18 consists of a unit 44 located near the first carousel 38, the unit 44 consisting of a first tubular shaft 45, driven by relative means 46 consisting of a mechanism which envisages a pair of toothed wheels 84 and 85 that engage with one another, one being keyed to the first tubular shaft 45 and the other to a powered shaft 86. The first shaft 45 rotates about its vertical axis Z1 and the top of the shaft is fitted with a vertical pin 47, parallel with the said vertical axis Z1. The above-mentioned continuous thread 5 is attached to this pin 47 in such a way that it slides freely, the thread extending from a thread feed unit 48. The feed unit 48 is located outside the sixth station 18 (as shown in figures 2 and 4) and consists of one or more reels 87 of thread 5, which is picked up and guided, inside the first tubular shaft 45, by tensioning means 57 (see figure 9), located near the first tubular shaft; the thread 5 is unwound mainly by the action of the first carousel 38 as it rotates (described below), combined with the movement of the pin 47. The unwinding means 57 may consist of a plurality of idling rollers 88, keyed near an oscillating shaft 89, with which the thread 5 is held taut during the stages in which it is tied on the bag 1 (described in more detail below). Opposite and above the said first shaft 45, is a second shaft 49, with a vertical axis, supported by a first horizontal arm 50 (see angle β in figures 7, 10, 18) which can be oriented on a horizontal plane between a position for ring 51 formation (shown in figure 9, as a dashed line in figure 7 and in figure 18), in which the second shaft 49 is coaxial with the first shaft 45, allowing the pin 47 to rotate about the second shaft in such a way that it preforms a portion of thread 5 into a ring 51, and a position for the set-down of the ring 51 thus formed, in which the second shaft 49 is opposite the bag 1 (see figure 7, continuous line), still supported by the grippers 40 of the first carousel 38, stationary at that moment, and vertically aligned with its mouth 4, so that the ring 51 is set down on the zone around the mouth 4. These end positions are defined by relative drive means 55, described below. In figures 18, 19, 20 and 21, the numeral 59 labels contrast means which operate upon the second shaft 49 and are located along the vertical axis of the bag 1. The said means consist of another horizontal shaft 60, supported by a small vertical shaft 61 attached to the unit 44 and which can rotate about its axis so as to stably orient and angle the arm 60 at the gripper 40 transit zone. The arm 60 also has a slot 62 at its free end 60a which can be oriented, designed to partially house the second shaft 49, when the latter is in the ring 51 set-down position. Again observing the sixth station 18 in figures 8, 9, 18, 19 20 and 21, the second shaft 49 is divided into an external bell 52 which is hollow and houses a ring 51 pick-up and release cylinder 53 in such a way that the latter slides axially (see arrow F5 in figures 8, 9, 20 and 21). The lower end of this cylinder 53 has an operating head 54, protruding from the bell 52, designed to allow the thread 5 to be wound around it and having a cavity 54c, which opens to the outside, surrounding the zone above the mouth 4, when the second shaft 49 is in the ring 51 set-down position: the head 54 acts as a "finger" for thread 5 winding. In order to wind the operating head 54 in this way, the bell 52 is integral with the first arm 50, which moves vertically (see arrow F6 in figure 9), as well as rotating as indicated above, driven by the means 55, which consist of a vertical rod 90 connected to a cam mechanism 91 (means shown by a dashed line in figure 9). Therefore, the first arm 50 can assume the following positions: a first, raised, idle end position, in which the operating head 54 has been moved away from the first shaft 45, though it may be vertically aligned with it, and does not interfere with the pin 47 (see dashed line in figure 7 and figure 8); a second, intermediate, operating position, in which the operating head 54 is on the horizontal plane slightly lower than the free end of the above-mentioned pin 47, thanks to lowering of the first arm 50, allowing the formation, on the cylindrical surface of the head 54, of a ring 51 by the rotation of the pin 47; in this position the first arm 50 is in the said ring 51 formation position (see figure 7); finally, a third, lowered, operating position, in which the cavity 54c of the operating head 54 surrounds the part above the mouth 4 of the bag 1, when the first arm 50 is in the above-mentioned ring 51 set-down position. More specifically, the ring 51 set-down stages are further illustrated in schematic figures 19, 20 and 21: figure 19 shows the arrival position of the first arm 50 on the vertical axis of the bag 1; in figure 20, the arm 50 completes a first stroke towards the bag 1 (arrow F50) to the point at which the cavity 54c surrounds most of the mouth 4 inside it, the stroke being vertically delimited by a ring 54a, integral with the free end of the cylinder 53, which makes contact with the arm 60. At this point, the further downstroke of the arm 50 (see figure 21 and arrow F21) is effected only by the bell 52 which, in this way, slides the ring 51 of thread 5 downwards, releasing it from the operating head 54 and setting it down on the part around the mouth 4. Obviously, the return of the first arm 50 at the first shaft 47 envisages firstly raising of the first arm until it returns to the configuration in figure 19, then its rotation in the opposite direction to that previously employed. Spring means 56 (a helical spring) are envisaged between the bell 52 and cylinder 53, being designed to allow the relative return stroke between the bell 52 and cylinder 53. If a greater operating speed were required of the knot set-down unit, the solution illustrated using the spring 56 could be substituted with the direct control solution schematically illustrated in figure 22. Here, the two elements, the bell 52 and cylinder 53, are controlled by independent control elements 50, 50a and 60, 61 which, in turn, are controlled by independent drive means consisting of separate cams 50c and 60c. To correctly tie off the zone around each mouth 4 on the bags 1, in this case and preferably, two of the above-mentioned tying rings are created, labelled 51 and 58, in two subsequent and substantially identical stages, as illustrated in figures 1, 10 and 11 and the relative letters. The first ring 51 is wound around the bag 1 and tightened around the zone around the mouth 4 thanks to the tensioning action of the above-mentioned means 57, that is to say, oscillation of the rod 89. Similarly, the second ring 58 is positioned over the first 51 and tightened around the zone around the mouth 4, again thanks to the oscillation of the rod 89 and due to the subsequent movement in direction of rotation F of the first carousel 38: in this way, the bag is tied off with a knot commonly known as a "clove-hitch" knot. It has been indicated that two tying rings are preferably created: this is important since the presence of a single ring cannot create a stable closure, whilst a pair of overlapping rings form the above-mentioned clove-hitch knot which, once tightened around the mouth 4, creates a stable, irreversible closure. More precisely, it should be noticed how the two rings are overlapped in the opposite direction to the direction of generation of the spiral by the thread 5 transit pin 47. That is to say, supposing that the spiral extends downwards, the second ring is placed over the first: stable closing of the knot can only be obtained in this way. As clearly shown in figures 7 and 10, the bag 1 thus formed has opposite portions of continuous thread 5 projecting from the bag tying zone, these portions connecting the bags 1 previously and subsequently formed to the bag just formed: in this way a continuous connection is created between the bags until the definitive formation of the individual bags (described in more detail below), thread 5 continuity also being maintained by the pins 42p, envisaged near each surface 41, which also tension the thread 5 as the first carousel 38 rotates. In figures 2, 3 and 12, the numeral 19 is used to label a seventh station, which feeds the labels 6 to the stationary first carousel 38 with a surface 41 at the seventh station 19. It should be noticed that the label in question, for reasons explained below, has a slot 22 on one side which, at its inner edge, forms a seat 23 which in the embodiment illustrated by way of example only is semi-circular. This seventh, feed station 19 for the individual labels 6 consists of a second horizontal arm 63, one end of which is equipped with grippers 64 designed to pick up an individual label 6 from a continuous strip of labels. The other end of this second arm 63 is attached to a third vertical shaft 65, which can be angled between a pick-up position, in which the gripper end 64 is located at the continuous strip of labels 6, enabling it to pick up and clamp the label 6 (shown with a continuous line in figure 12), and a release position, in which the gripper end 64 is rotated through an angle α, moved towards the fourth station 14, allowing the label 6 to be housed in the seat 42 on each surface 41. It should be noticed that each surface 41 is equipped with grippers (described below), which momentarily clamp the label 6 to the surface, until the label is subsequently released, as described below. The second arm 63 is driven by a horizontal rod 91 connected to a mechanism 92 consisting of another arm 93 controlled by a cam 94. The seventh station 19 is inserted inside an eighth station 20, designed to allow the label 6 to be attached to the continuous thread 5 at a predetermined point 6a. In addition, the eighth station 20 has second means 21 for cutting the remaining portion of thread 5 envisaged beyond the point at which the thread was attached to the label 6. The eighth station also contains means 24 for insertion of the label 6 at the above-mentioned tying zone, in such a way that the latter is housed in the semi-circular seat 23. As shown in schematic figure 13, to better create the joins between the thread 5, label 6 and bag 1 and the relative thread cutting, the above-mentioned working zones 39 are positioned one after another in a straight line, each separated by a space S1 substantially equal to the working length of the thread 5 required to produce the bag 1, the end of which may be attached to the label 6: in other words, two successive bags 1 linked to a gripper 40 are separated by a distance S equal to the working length S1 of the thread 5 envisaged between a label 6 and the relative bag 1, i.e.: equal to the distance between two successive cuts. In the order derived from the feed line A, the numeral 68 is used to label means for gluing the label 6 to the thread 5 at the above-mentioned predetermined point on the thread 5. These gluing means 68 (see figure 1h) may consist of a cold or hot-melt liquid adhesive sprayer 95, located near the zone at which the label 6 is housed on the surface 41. The sprayer 95 may move along its longitudinal axis, starting from above the label 6, and approaching the label only when the latter is housed in the seat 42 on the surface 41. Again close to the gluing means 68, the above-mentioned thread 5 cutting means 21 are envisaged, immediately upstream of the gluing sprayer 95 (relative to the feed line A), allowing it to be detached almost simultaneous to the depositing of the drop of glue between the label 6 and thread 5. With reference to figures 23 and 24, it can be seen that the surface 41 has a tab 41p which forms the seat 42; beneath this tab is one end of a gripper element 41h (already referred to) which moves downwards, away from the tab 41p, driven by means generically labelled 41m. The bottom of the tab 41p preferably has a groove 41i, in which the thread 5 may be housed; the gripper element 41h, in its closed position, clamps together the label 6 - thread 5 assembly beneath the tab 41p: the duration of this clamping stage is sufficient to allow the glue to bind the thread 5 and label 6 during the cutting stage, without the risk of them being separated. The second cutting means 21 (again see figure 1h) may consist of a pair of blades 96, angled and moved vertically towards and away from the thread 5; these blades 96 may be shears. Therefore, the thread 5 is cut at a zone outside the surface 41 which houses the label 6. Proceeding along the feed line A, the eighth station 20 also comprises a second carousel 66, which rotates about its vertical axis Z2 and in a direction F1 concordant with the first carousel 38 at the fourth station 14. The second carousel 66 is equipped with second pick-up means 67 for the bag 1 only, which intersect at a first zone PZ1 with the first pick-up means 15, that is to say, the grippers 40. The second pick-up means 67 consist of second grippers 98, which pick up a single bag 1 at a point above the tying zone and different to that of the gripper 40 pick-up zone; the bag 1 is picked up by the second grippers 98 when the first carousel 38 pauses between the tying, gluing and cutting operations on successive bags 1. As is more clearly shown in figure 15, the second grippers 98 pick up the bag 1 from above and along an axis vertical to the bag, to avoid intercepting the first grippers 40, which hold the bag 1 according to a horizontal plane, as already seen. Moreover, every second gripper 98 comprises a gear ratio unit 98g (visible in the detail in figure 16) which, as indicated more clearly below, allows the corresponding second gripper 98 to rotate about its vertical axis V, winding the thread 5 around the mouth 4 of the bag 1. Each gear ratio unit 98g comprises a first toothed wheel 98r, keyed to a small vertical shaft 98a parallel with the corresponding gripper 98 support shaft 98b, a second toothed wheel 98c, engaged with the first 98r, being keyed to the shaft 98b. In addition, the gear ratio unit 98g has a seat 98s for the insertion of a clutch unit 69, described in more detail below. Returning to the second carousel 66 and second grippers 98, as the second carousel rotates, it brings the bag 1 near to the above-mentioned means 24 for insertion of the label 6 at the thread 5 tying zone. The label insertion means 24 are substantially located between the zone in which the second cutting means 21 and gluing means 68 operate and the second carousel 66. As it rotates, the second carousel 66 brings the bag 1 just picked up to a zone, labelled PZ2 in figure 12, subsequent to the first zone of intersection PZ1 relative to the direction of rotation F1 of-the second carousel 66, and where it can be reached by the insertion means 24. Above the second carousel 66 and on the vertical axis of the second zone PZ2, is the above-mentioned clutch unit 69 (see figure 17). This clutch unit 69 consists of a circular clutch 70 attached to a shaft 70a supported by a bridge structure 70p housing the elements which move the clutch 70 vertically and allow it to rotate. These elements, by way of example only, may consist of a rocker arm 70b and relative control tappets 70c and a pair of pulleys 70m, 70n keyed to a rotating tube 70h and to the shaft 70a, and connected to one another by a toothed belt 70e. The clutch 70 must engage inside the corresponding seat 98s of the second grippers 98 when the latter arrives at zone PZ2 (see arrow F70 in figure 17) and begin rotating there. The drive created by the clutch 70 allows the grippers 98 to rotate, thanks to the latter's connection to the gear ratio unit 98g, thus winding the thread 5 around the tying zone on the mouth 4 of the bag 1, whilst at the same time the label 6 is moved towards and inserted in the said zone by the insertion means 24. The gear ratio unit allows the second grippers 98 to effect a limited number of turns to wind the thread around the mouth 4; the number of turns performed by the second grippers 98 preferably being between 2 and 4. The label 6 pick-up stage occurs as the bag 1 is transferred from the first carousel 38 to the second carousel 66, whilst the label is attached to the bag 1 as the thread 5 is wound by the grippers 98; this prevents excessive tensioning of the thread 5 during the transfer and winding movements. The label 6 insertion means 24 consist of a horizontal arm 72, one free end of which is equipped with grippers 73 for label 6 pick-up and release. The third arm 72 is controlled by cam means 74, designed to allow an articulated parallelogram rototranslation on a horizontal plane of the arm, from a position in which it picks up the label 6 located on the surface 41 of the first carousel 38, to a label 6 attachment position, in which the third arm 72 moves backwards, away from the first carousel 38, then diverts towards the grippers 98 (see arrow F7 in figure 12) and attaches the label 6 to the bag 1. In order to allow this movement by the third arm 72, the cam means 74 consist of a pair of horizontal rods 74a and 74b, connected in the shape of an articulated parallelogram and in turn controlled by a toggle 99 controlled by a cam profile 100 which cyclically controls the above-mentioned movement of the third arm 72 in both directions. Once the label 6 has been attached to the bag 1, the clutch 70 in the clutch unit 98g is raised and allows the second carousel 66 to continue its rotation F1. As it turns, the second carousel 66 arrives at an unloading zone PZ3, obviously after the second zone of intersection PZ2 relative to the direction of rotation F1 of the same carousel. A conveyor belt 75 is located at this unloading zone PZ3, below the second carousel 66, and it is here that the grippers 98 release the bags 1 just produced. The conveyor belt 75 transfers the bags 1 to a subsequent packaging station 76, of the known type and, therefore, not fully illustrated and described.

Claims: A packaging apparatus, in particular for the production of bags (1) for products for infusion, each of the bags (1) consisting of a piece (2) of woven fabric, in which a dose (3) of said product is deposited; said dose (3) being closed in the fabric by folding over the sides of the piece (2) of fabric, bringing together the free edges at a given point, forming the mouth (4) of the bag, at which a tying thread (5) is envisaged, being wound around the bag; there being a label (6) also attached to the thread (5), the label being designed to allow the bag (1) to be supported and handled while making an infusion, the apparatus comprising one after another and along a feed line (A) : a first station (7) which feeds a continuous strip (8) of said fabric towards a second station (9) equipped with a transverse cutting unit (10) for the strip (8), being designed to create a series of flat pieces (2) of fabric; a third station (11), having means (12) for transforming the piece (2) of fabric from the flat configuration to a bag configuration, the bag being tubular in shape and having an open top which forms the mouth (4); the third station (11) also comprising means (13) for feeding a dose (3) of the product into the bag; a fourth station (14), having first means (15) for picking up the tubular bag by the portion of the bag below the mouth (4), this fourth station (14) being designed to transfer the tubular bag to a fifth station (16), having first means (17) for cutting a predetermined part of the upper end of the tubular bag, that is to say, the mouth (4), which is not held by the pick-up means (15); a sixth station (18), being located downstream of the previous station, and designed to wind and tie off the continuous thread (5) around the remaining zone of the mouth (4) end, forming a closed bag (1) containing a single dose, having opposite projecting portions of thread (5) connecting the previous and subsequent bags; a seventh station (19) for feeding a label (6) to the bag (1) with the said projecting portion of thread (5) as it moves forward; an eighth station (20), designed to allow attachment of the label (6) at a predetermined point on the continuous thread (5); the eighth station (20) having second means (21) for cutting the remaining portion of thread (5) which extends beyond the point at which the label (6) is attached; characterised in that the sixth station comprises: a first tubular shaft (45), driven by means (46) and rotating about its vertical axis (Z1), the upper end being fitted with a pin (47), this being vertical and parallel with said vertical axis (21); the continuous thread (5) extending from a thread feed unit (48) and passing through the pin (47); a second shaft (49) with an operating head (54) opposite the first shaft (45), with vertical axis and supported by a first horizontal arm (50) orientable between a ring (51) formation position, in which the second shaft (49) is coaxial with the first shaft (45), allowing the pin (47) to rotate about the second shaft (49), preforming a portion of thread (5) into a ring (51) shape around the operating head (54), and a ring (51) set-down position, in which the second shaft (49) is opposite the bag (1) in the fourth station and vertically aligned with its mouth (4), with means (52) to slide the ring (51) downwardly from the operating head on the zone around the mouth (4) of the bag (1). The apparatus according to claim 1, characterized in that the label (6) has a slot (22) on one side forming, at its inner edge, a seat (23), the eighth station (20) having means (24) for inserting the label (6) at the bag tying zone in such a way that the latter is housed in the seat (23). The apparatus according to claim 1, characterized in that the means (12) which form the piece (2) of fabric consist of an open tubular element (25), being positioned vertically relative to the feed line (A); the tubular element (25) being supported and moved by the end of a horizontal arm (26) attached to a support structure (27) on the apparatus; the tubular element (25) being vertically and axially mobile relative to a fixed, tubular internal guide and support element (25g) between two end configurations, these being respectively raised, in which the tubular element (25) completely surrounds the guide element (25g), and a lowered operating configuration, in which the tubular element (25) forms a lower extension of the guide element (25g), intercepting the flat piece (2) of fabric and deforming it into a bag shape. The apparatus according to claims 1, 3 and 4, characterized in that it envisages a vertical presser or ejector (28), this being positioned opposite the tubular element (25) and being moved by relative means (29) towards and away from the bag, inserting a dose (3) of product into the bag when the tubular element (25) is in the lowered position. The apparatus according to claim 3, characterized in that the flat piece (2) of fabric rests on a contrast and sliding surface (25p), said surface having a hole (25f) for drawing the piece (2) of fabric, the hole being coaxial to the tubular element (25); holding means (25r) being envisaged close to the hole (25f), these means being designed to clamp the part of the bag (1) close to the lower zone of the surface (25p) when the tubular element (25) is in the lowered and the raised positions. The apparatus according to claims 1 and 3, characterized in that the means (13) for feeding a dose (3) consist of a feed hopper (30) for said product, being positioned above a product holder and dosing drum (31), being able to rotate about its vertical axis (Z3); said drum (31) having a plurality of through-holes (33), forming compartments which hold the product, and being evenly distributed over the circumference of the drum, the lower section of the drum being closed by a base (32) having a single hole (32f) for the passage and discharge of the dose (3) and being vertically positioned relative to the presser (28). The apparatus according to claim 6, characterized in that means (34) designed to allow the even distribution of the product inside the holes (33) operate on the drum (31). The apparatus according to claim 6, characterized in that the means (34) consist of a plurality of mixing blades (35), rotating about said vertical axis (Z3) and at the centre of the drum (31). The apparatus according to claim 3, characterized in that the support arm (26) for the tubular element (25) is mobile between two end positions, towards the support structure (27) and then away from the said structure, placing the tubular element (25) in a position which allows the bag to be picked up by first pick-up means (15). The apparatus according to claim 1, characterized in that the fourth station (14) consists of a first carousel (38) with vertical axis of rotation (Z), having a plurality of working zones (39), these being evenly distributed around the circumference of the first carousel (38); each of the working zones (39) comprising a gripper (40) for clamping the bag (1) at the portion below the mouth (4), forming the first pick-up means (15), and a surface (41) on a plane above the grippers (40) and alternated with the grippers; each surface (41) having a seat (42) for housing a label (6). The apparatus according to claim 10, characterized in that between two grippers (40) there is a space (S) which is substantially equal to the working length of the thread (5) and which may be used at least between the bag (1) and label (6). The apparatus according to claim 1, characterized in that the fifth station (16) consists of at least one blade (43) supported by a structure positioned near the fourth station (14); said blade (43) being mobile between a forward operating position, in which the blade (43) intercepts the portion of the bag (1) which forms the mouth (4) at a predetermined height (H) relative to the first pick-up means (15), and an idle position, in which the blade (43) has moved away from the bag (1). The apparatus according to claim 1, characterized in that the fifth station has at least one pair of jaws (16g) for clamping the free end of the mouth (4) in such a way as to form a cylindrical portion with the said end; the jaws (16g) being positioned and mobile above the first pick-up means (15) between two end positions, these being respectively an idle position, in which the jaws (16g) are moved away from one another and from the mouth (4), and an operating position, in which the jaws (16g) are brought together and clamp the part above the mouth (4), allowing the end to be vertically tensioned in contrast to the said forward cutting position of the blade (43). The apparatus according to claim 13, characterized in that the jaws (16g) are fitted with an ejection unit for the cutting waste, this being located above the jaws and consisting of a vacuum duct (16c). The apparatus according to claim 1, characterized in that the first arm (50) is operated upon by means (59) designed to define the set-down position for the ring (51); said means (59) consisting of a horizontal arm (60), this being supported by a vertical shaft (61) attached to the unit (44) in such a way as to stably orient the arm (60) at the fourth unit (14); said arm (60) having a slot (62) at its free end, it being possible to orient the latter on the fourth station (14) and the slot being designed to partially house the second shaft (49) . The apparatus according to claims 1 and 15, characterized in that the second shaft (49) is divided into a bell (52) housing, in such a way that it can slide axially, and a pick-up and release cylinder (53) for the ring (51); the lower end of the cylinder (53) having an operating head (54), protruding from the bell (52) and having a cavity (54c) opening to the outside and surrounding the zone around the mouth (4), being designed to have the thread (5) wound around it; said bell (52) being integral with the first arm (50), this being vertically mobile, driven by means (55) between several different positions, including: a first, raised, idle position, in which the operating head (54) is moved away from the first shaft (45) and does not interfere with the pin (47) ; an intermediate operating position, in which the operating head (54) is on a horizontal plane lower than the free end of the pin (47), allowing the formation of a ring (51) at the ring formation zone of the first horizontal arm (50), and a lowered operating position, corresponding with the said turned ring set-down position of the first horizontal arm (50), in which the cavity (54c) of the operating head (54) surrounds the part around the mouth (4) and allows the ring (51) to be released on the part around the mouth as the bell (52) slides on the cylinder (53), being vertically and axially stopped by a limit ring (54a), this being located at the free end of the cylinder (53) and being designed to make contact with the wall (60) as the horizontal arm (50) moves towards the lowered operating position. The apparatus according to claim 16, characterized in that between the bell (52) and the cylinder (53) there are spring means (56), being designed to allow a return stroke between said bell (52) and said cylinder (53) when the bell returns to the raised end position. The apparatus according to claim 1, characterized in that the continuous thread (5) is fed from a station (48), being located outside the sixth station (18), the thread being guided and tensioned within the first tubular shaft (45) by tensioning means (57) located near to the first tubular shaft. The apparatus according to claim 16, characterized in that two tying rings (51, 58) are created using the continuous thread (5) on each bag (1) during two successive stages, one being placed over the other and locked on the zone around the mouth (4) each time the first arm (50) returns to the ring formation position. The apparatus according to claims 1 and 10, characterized in that the seventh station (19) that feeds a label (6) consists of a second horizontal arm (63), having an end fitted with grippers (64), being designed to pick up an individual label (6) from a continuous strip of labels; the other end of the second arm (63) being attached to a third vertical shaft (65), it being possible to angle it between a pick-up position, in which the gripper (64) end is positioned at the continuous strip of labels (6) and in a configuration for the pick-up and clamping of the label (6), and a release position, in which the gripper (64) end is turned through an angle (α) and moved towards the fourth station (14), allowing the label (6) to be housed in a seat (42). The apparatus according to claims 1, 2 and 10, characterized in that the eighth station (20) comprises a second carousel (66), being able to rotate about its vertical axis (Z2) and in a direction (F1) concordant with a first carousel (38); the second carousel (66) being equipped with second means (67) for picking up the bag (1), intersecting in a first zone of intersection (PZ1) with said first pick-up means (15) and being designed to pick up the bag (1) from the latter above a tying zone and along a vertical axis of the bag (1) and transfer it close to the means (24) which insert the label (6) at the zone tied using the thread (5). The apparatus according to claims 1 and 21, characterized in that between the seventh station (19) and the second carousel (66) there are means (68) for gluing the predetermined point of the thread (5) to the label (6) before the bag (1) passes into the second carousel (66). The apparatus according to claims 1 and 22, characterized in that close to the gluing means (68) and the second carousel (66) there are second means (21) for cutting the thread (5) after the point at which the thread is glued to the label (6). The apparatus according to claims 2 and 22, characterized in that between the gluing means (68) and the second carousel (66) there are means (24) for inserting the label (6) at said tying zone. The apparatus according to claim 21, characterized in that the second pick-up means (67) of the second carousel (66) rotate about their vertical axis (V) and intersect a second zone of intersection (PZ2) with the insertion means (24), when the second carousel (66) moves, after the first zone of intersection (PZ1) in the direction of rotation (F1), simultaneously winding the thread (5) around the tying zone and inserting the label (6) in the said zone. The apparatus according to claims 1 and 2, characterized in that the means (24) for inserting the label (6) consist of a third horizontal arm (72), having a free end equipped with grippers (73) for the pick-up and release of the label (6); said third arm (72) being driven by cam means (74) designed to cause rototranslation of the third arm on a horizontal plane from a position in which the label (6) is picked up close to a fourth station (14), this being equipped with a working zone (39) in which the label (6) is housed, to a label (6) attachment position, in which the third arm (72) is moved away from the fourth station (14) and allows the label (6) to be attached to the bag (1). The apparatus according to claim 21, characterized in that the second pick-up means (67) of the second carousel (66), at a second point of intersection (PZ2), are acted upon by a clutch unit (69), this unit being designed to activate rotation of the second pick-up means (67), allowing winding of the thread (5). The apparatus according to claim 27, characterized in that the second carousel (66) envisages an unloading zone (PZ3), after the second zone of intersection (PZ2) relative to the direction of rotation (F1) of the same carousel; there being at the said unloading zone, a conveyor-belt (75), positioned below the second carousel (66), and designed to transfer the bags (1) to a packaging station (76). The apparatus according to claim 10, characterized in that each of the first grippers (40) consists of a body (40a), having a pair of jaws (40b, 40c) which rotate about the vertical axis (40Z) of the body (40a); said jaws (40b, 40c) being shaped in such a way that, when closed, they form a complementary seat (40s) which supports and houses the portion below the mouth (4). The apparatus according to claim 10, characterized in that each surface (41) has at least one pair of vertical pins (42p), being located next to the corresponding seat (42) and designed to hold a continuous thread (5) joining the bags (1) to the labels (6) in succession, defining half an arc which copies the external circumference of the first carousel (38) when the first carousel completes a rotation along the feed line (A). The apparatus according to claim 10, characterized in that each surface (41) has a tab (41p), forming the seat (42); beneath the tab (41p) there being one end of a gripper element (41h), being mobile towards and away from the tab (41p), driven by means (41m); the base of the tab (41p) also having a groove (41i), this being designed to house the continuous thread (5). The apparatus according to claims 16 and 19, characterized in that the pair of rings (51, 58) is created by overlapping the two rings in the opposite direction to the direction of generation of the spiral formed by the pin (47) for passage of the thread (5). A method of producing of a bag (1) for products for infusion, wherein the bag (1) is formed in a series of stages, comprising: a first stage, in which a flat piece (2) of fabric is formed into a bag and a dose (3) of the product is deposited in the bag; a second stage of folding over the sides of the fabric in such a way that the dose (3) is closed inside until the free edges of the sides form a mouth (4) of the bag (1), creating a bundle configuration; a third stage, in which the bag (1) is closed with a portion of thread (5) wound around the mouth (4) along a path creating twin tying rings (51, 58), one overlapping and contiguous with the other; a fourth stage, in which a label (6) is attached to an end of the thread (5) protruding from the bag (1); a fifth stage, in which the joining portions of the thread (5) and label (6) are wound around the mouth (4) and, immediately upon completion of this stage: a sixth stage, in which the label (6) is stably attached to the bag (1) at the mouth (4); characterised in that the third stage comprises: winding a first tying ring (51) of thread (5) around an operating head (54) on a vertical shaft (49) in a ring formation position thereof by means of a pin (47) which rotates on a tubular shaft (45) around the operating head (54), the thread (5) passing through the pin (47); moving the operating head (54) to a position opposite to and in vertical alignment with the mouth (4) of the bag (1); sliding the first tying in ring (51) downwardly from the operating head (54) on the zone around the mouth of the bag (1) and tightening said ring around the zone around the mouth (4); winding a second tying ring (58) of thread (5) around the operating head (54) in similar way as for the first tying ring (51); lowering the second tying ring (58) over the first ring (51) and on the zone around the mouth of the bag (1) and tightening said second ring around the zone around the mouth (4), so that a knot known as a clove-hitch knot is formed around the mouth (4) of the bag (1). The method according to claim 33, characterized in that the sixth stage for stably attaching the label (6) to the bag (1) is effected by slotting the label onto the mouth (4) by means of a seat (23) on the label, encompassing the mouth (4). The method according to claim 33, characterized in that the fifth stage for winding the thread (5) is effected by rotating the bag about its vertical axis parallel with the mouth (4), thus shortening the thread and bringing the label closer. The method according to claim 33, characterized in that before the third stage for closing the bag (1), a stage for cutting part of the free portion of the mouth (4) is envisaged, transforming this portion into a cylindrical configuration designed to have the thread (5) wound around it during the subsequent closing stage.

Inventors: REA DARIO, REA, DARIO
Applicants: IMA SPA, I.M.A. INDUSTRIA MACCHINE AUTOMATICHE S.P.A.
Application year: 1998
Main classification: B65B29
IPC codes: B65B29