DESCRIPTION

Technical Field

The present invention relates to the fields of plants for forming packs of plastic bags or the like, having holes along one edge to be coupled to corresponding needles for forming and supporting the packs. More in particular, the object of the present invention is an apparatus for moving packs of plastic bags, of the type with needles for supporting the packs.

State of the Art

For many years now, plants are well known for forming packs of plastic bags, of the type with needles for supporting the packs. One of these plant is to form packs of bags is the so-called "Wicket". It provides for using a moving device comprising a rotor formed by two rotating drums that are keyed onto a common shaft, present a plurality of arms exiting from the drum axis in a radial manner, and are suitable to support a plastic bag. On each pair of coplanar arms there are means (for instance pneumatic means) for maintaining the plastic bag in position. Practically the bag is translated from a welding and cutting area onto a pair of arms of the Wicket rotor; these arms are then rotated by 180° so that each bag is overturned into the forming position and then released and piled on a bag below to form a pack.

More in particular, each bag is provided with a pair of holes at one its own edge; when the bag arrives into the pack forming station these holes are centered in correspondence of a complementary pair of needles. In this station the needles are arranged for forming the packs, i.e. each needle is positioned verti- cally. In numerous configurations the needle is in almost vertical position rather than in vertical position; for instance it is displaced by 15° with respect to its ver- ticalness.

When inserted onto the needles, the bag is bound to them with one its edge, whilst the rest of the bag falls downwards, thus taking a mainly vertical di- rection.

The subsequent bags are inserted onto the same needles, stacking the previous bag, so as to form a pack that "hangs" from the needles; this pack will be then moved via a movement line towards an unloading station for unloading the formed packs.

Here the packs are usually pulled out manually by an operator who raises and thus removes them from the needles and puts them for instance into a car- riage to bring them to the storage area.

In some plants, robots may provided instead of the operator, making substantially the same operations.

Object and summary of the invention

One object of the present invention is to provide an apparatus for moving packs of plastic bags, of the type with needles for supporting the packs, that allows to make the step of unloading the formed packs easier than in known apparatuses.

A further significant object of the present invention is to provide an apparatus for moving packs of plastic bags, of the type with needles for supporting the packs, that allows to reduce the staff required to control a forming plant.

One further important object of the present invention is to provide an apparatus for moving packs of plastic bags that allows easily to store a high number of packs.

These and other objects, that will be more apparent below, are achieved through an apparatus according to claim 1 below.

According to a first aspect, the invention relates to an apparatus for moving packs of plastic bags, of the type with needles for supporting the packs, comprising the following essential components: a) one station for forming the packs of bags, where each pack is inserted, in correspondence of at least one corresponding hole, onto at least one support needle arranged for forming the packs, wherein said needle is vertical or almost vertical, b) one unloading station for unloading the formed packs, and c) one movement line for moving said needles from said forming station to said unloading station; the apparatus characteristically comprises: overturning means for overturning the needles moving them from said vertical or almost vertical arrangement to a horizontal or almost horizontal arrangement, thus allowing the packs of bags to be pulled out; and means for pulling out the packs from the needles in said horizontal or almost horizontal arrangement.

Each pack is preferably formed by bags having pairs of holes along one edge; the apparatus therefore provides preferably for pairs of needles inserted into the pairs of holes of the bags of the packs.

According to a further aspect, the invention also relates to a method for forming packs of bags providing for: inserting a plurality of plastic bags onto at least one needle in vertical or almost vertical arrangement; subsequently overturning the at least one needle moving it to a horizontal or almost horizontal arrangement; and subsequently pulling out this bag from the at least one needle in this horizontal or almost horizontal arrangement.

The invention also relates to a system implementing said method through the apparatus illustrated above.

According to a further aspect, the invention relates to an apparatus for moving packs of plastic bags, of the type with needles for supporting the packs, comprising the following essential components: a) one station for forming the packs of bags, where each pack is inserted, in correspondence of at least one corresponding hole, onto at least one support needle arranged for forming the packs, wherein said needle is vertical or almost vertical, b) one unloading station for unloading the formed packs, and, preferably, c) one movement line for moving said needles from said forming station to said unloading station; the apparatus characteristically comprises a module for receiving the packs unloaded from the unloading station designed to receive the packs pulled out from said overturned needles. In this receiving module there are preferably provided: one receiving area for receiving the packs from the unloading station; a plurality of hanging elements for respective packs; one area for handling the packs on said hanging elements and one movement path for moving said hanging elements from the receiving station to the handling station, comprising a segment in which an accumulation area for the packs is defined and along which the hanging elements are oriented so that the packs are transverse, relative to the pack width, to the feeding direction in said segment with accumulation area.

Brief description of the drawings

Further characteristics and advantages of the present invention will be more apparent from the description of a preferred, although not exclusive, embodiment, illustrated by way of non limiting example in the attached tables of drawings, wherein:

figure 1 is an axonometric schematic top view of a plant with the appa- ratus according to the invention;

figure 2 is a schematic side view of the forming station for forming packs of bags of the apparatus of figure 1 , with a bag carried by the arms of a Wicket rotor;

figure 3 is a schematic side view of the overturning station for overturning the support needles of the apparatus of figure 1 , wherein a broken line shows the initial and intermediate step of needle overturning;

figure 4 is a schematic side view of the pack unloading station and the pack receiving area of a receiving module, with a pack beginning to be pulled out from respective needles;

figure 5 is an enlargement of figure 4 showing a support needle moving towards the receiving module;

figure 6 is an enlargement of figure 4 showing the pack transferred onto the receiving module;

figures from 7 to 10 show schematic side cut-away views of the steps of: pulling out a pack from a pair of needles (only one needle of the pair of needles is shown), unloading it and receiving it in the receiving module;

figures 1 1 , 12, and 13 are axonometric schematic top views of a portion of line conveyor belt of the movement line of the apparatus as in the previous figures, where a platform is highlighted carrying a pair of needles, with the needles respectively arranged for forming the packs, overturned for pulling out the packs and rotated to be adjusted longitudinally along the platform to regulate the center-to-center distance between the same needles;

figure 14 is a schematic top view of the receiving module with the unloading station of the apparatus as in the previous figures;

figure 14a is a schematic top view of a variant of the receiving module of figure 14;

figure 5 is a schematic front view of a part of the path of the hanging el- ements in the receiving module of the apparatus as in figure 14, related to the movement from the receiving area to the accumulation area;

figure 16 is a schematic front view of part of the path of the hanging elements in the receiving module of the apparatus as in figure 14, related to the movement from the handling area to the receiving area;

figure 17 is an enlarged portion of figure 1 , where the parts of the carriages for moving the hanging elements in the receiving module are highlighted; figure 8 is a vertical cut-away view of a carriage of figure 17, where a broken line indicates the movement of the clutch mechanism to block/release the carriage.

Detailed description of an embodiment of the invention

With reference to the previously mentioned figures, the letter I indicates a plant comprising an apparatus according to the invention for moving packs of plastic bags, of the type with needles for supporting the packs, while the num- ber 10 indicates the apparatus as a whole.

The plant I comprises for instance a production station 1 1 for producing each bag S, for instance by cutting and welding a continuous plastic film, and a Wicket rotor 12 of the known type that rotates the bags by 180° bringing them from the production station 1 1 to the forming station 13 for forming packs P of the apparatus 10.

The apparatus 10 therefore comprises as essential components: the forming station 13, where the bags S arrive via the arms 12A of the Wicket rotor 12 (see figure 2) and are accumulated in packs inserted with respective pairs of holes onto pairs of needles 14; one unloading station 15 for unloading the packs; and one movement line 16 for moving the needles with the packs (or without them if they have not been formed) from the forming station 13 to the unloading station 15.

In this forming station 13 the needles 14 for supporting the packs are arranged for forming the packs, i.e. they are almost vertical, preferably displaced from the verticalness by an angle of about 15° (obviously, in other embodiments the needles may be displaced by an angle other than this one, or they also maybe substantially vertical). In this example the movement line 16 is comprised of a conveyor belt 16A onto which there are platforms 17 carrying pairs of needles 14, the platforms being arranged at regular distance from one another. The conveyor belt 16A is preferably a belt, whose lower surface is toothed so as to be coupled to a movement toothed member (not shown). The conveyor belt is preferably a closed loop with at least two idler rollers (not shown in the figures), at least one of which is motorized; the conveyor belt has therefore two segments, one upper segment for moving the platforms 7 with the pairs of needles from the forming station 13 to the unloading station 15, and one lower segment returning from the unloading station to the forming station.

The movement line develops preferably rectilinear, i.e. the segment between the forming station 13 and the unloading station 5 is rectilinear.

According to the invention, the apparatus characteristically comprises overturning means 18 for overturning the needles moving them from the ar- rangement for forming the packs, i.e. the vertical or almost vertical arrangement, to a substantially horizontal (or, in other embodiments, almost horizontal) arrangement to allow the packs P to be pulled out, and pulling out means 19 for pulling out the packs from the needles in horizontal arrangement, after they have achieved the unloading station 15.

According to some advantageous embodiments, the overturning means

18 for overturning the needles 14 are preferably placed in an overturning station 20 comprised between the forming station 13 and the unloading station 15.

The pulling out means 19 are preferably arranged in the unloading station

15.

Suitably, according to a preferred embodiment, on the movement line

(adequately on the upper segment, in the case of a conveyor belt) between the forming station 13 and the unloading station 15 there are three platforms 17 with pairs of needles 14 , i.e. one platform with a pair of needles in the forming station 13 to receive the bags and form the pack, one platform with a pair of needle in the overturning station 20, and one platform with a pair of needles in the unloading station 15 to unload the pack.

In other embodiments both the overturning means and the pulling out means may be arranged in the unloading station (i.e.the overturning station is integrated in the unloading station). In this case between the forming station and the unloading station on the movement line (suitably on the upper segment, in the case of a conveyor belt) there may be two platforms with pairs of needles, i.e. one platform for each station.

It is also possible to combine the forming, overturning and unloading stations into a single station, i.e. integrate the means for forming the packs, the means for overturning the needles and the means for pulling out the packs in only one station. It is thus possible to have just one pair of needles.

Obviously, in other embodiments the platforms for the pairs of needles may be more than three, according to the needs, and obviously in other embodiments the packs may be supported by a single needle or by more than two needles, and therefore the platforms will carry a corresponding number of needles.

In some embodiments the overturning means 18 comprise an axis 21 of rotation for the pair of needles 14 and means for driving the needles into rotation about this axis 21 , for example a movable pusher 22 designed to impact against the almost vertical needles according to a direction transverse to the axis of rotation of the same needles, thus pushing them in the direction of rota- tion/overturning. In figure 3 the pusher 22 comprises a translation actuator in the form of a pneumatic cylinder, wherein a continuous line indicates the movable member thereof when completely extracted after the push while a broken line indicates the same member pushing the needle (also the needle is in broken line).

Preferably, the packs are formed in the forming station 13 substantially in correspondence of a first side 16B of the movement line 16, with the packs hanging on the respective pairs of needles 14 along this first side 16B. Practically, the bags have the pairs of holes for the needles in correspondence of one their own edge, arranged near this first side 16B and parallel to it. With the axis 21 of rotation for the needles an overturning direction f is associated; this direction is such that the overturned needles are directed from the second side 16C, opposite to the first side 16B, of the movement line towards the outside. In particular, as shown in figures 1 1 , 12, and 13, the axis 21 of rotation is a shaft, which develops near the second side 16C of the movement line and onto which arms 17A are fixed for respective needles 14, each of which develops transverse to the line 16, with the respective needle developing from the end of said arm opposite to the end onto which the same needle is fixed. The needle rotates integral with the respective arm. In this example of embodiment the needle 21 is fixed onto the platform 17 and the arm 17A is hinged in a rotatory manner to the rotating shaft.

There are preferably adjusting means 22 for adjusting the position of the needles along the axis of rotation. In this example, these adjusting means consist of a vise-like cylindrical coupling between the end of the arm 17A and the shaft 21 that avoids translation along the shaft but allows rotation about it, so that, by releasing the vise, the arm 17A with the needle may be translated, thus adjusting the position of the needle. In this example the platform 17 comprises, for each needle, an L-shaped bracket fixed to the belt conveyor of the line 16, at one end of which is fixed the shaft to which the arm 17A with the needle 14 is hinged (L-shaped bracket and shaft 21 form a U-shaped support).

The apparatus adequately comprises also one receiving module 23 for receiving the packs P unloaded from the unloading station 5, the module being arranged in front of the same unloading station and directly receiving the packs pulled out from the overturned needles.

Preferably, during the unloading step, the needles of the pair carrying the pack are overturned and aligned with (or more in general, facing) a corresponding pair of support stems 24 defined on support elements belonging to the re- ceiving module 23, as better explained below. The pack of bags being unloaded can be pulled out from the needles and inserted with its own holes into the stems 24. More in particular, each stem 24 has a small tube 24A inserted onto its central body 24B, so that pairs of tubes are inserted in the respective pairs of holes of the packs when these latter are unloaded onto the stems. To pull out the pack from the stems, the operator shall simply remove the pairs of tubes 24A from the bodies 24B, with the pack attached to them. Obviously, instead of the tubes 24A different elements may be provided for supporting the packs, for instance U-shaped bars known in traditional plants for forming packs.

Figures from 4 to 10 show the pack moving from the needles (for the sake of simplicity, in the figures are shown only one needle of the pair of needles supporting the pack and only one corresponding stem). It should be noted that the needle 14 and the support stem 24 are preferably into contact or, anyway, they face each other so as to avoid free spaces downwards that could make the pack fall or block it when moving from the needle to the stem (this is clearly shown in figures 7 to 10).

According to some embodiments, the pulling out means 19 comprise pushing means 25 for pushing the pack from a position adjacent to the base of the needle 14 to a position on the support stem 24 of the receiving module 23. Preferably, in this configuration (figures 7-10) each needle 14 is comprised of an inner rod 14A and an outer sleeve 14B sliding on the inner rod 14A; the formed pack of bags supported by the needle is arranged on the sleeve 14B. The pushing means 25 comprise a first part 26 for pushing the sleeve 14B until it achieves the support stem 24, and a second part 27 for pushing the pack towards the stem 24 according to a preset sequence. For instance, the second part 27 is translated to push, from the rear, the pack P from the base towards the point of the sleeve 14B (figures 5, 7, and 8). The first part 26 is then trans- lated to push the sleeve 14B onto the inner rod 14A (figure 9), until the point of the needle/sleeve abuts against the stem (the needle/sleeve is preferably sharped and the stem is hollow on the front to receive the needle point). The second part 27 is then further translated to push the pack from the point of the needle/sleeve until this latter translates onto the stem 24 (see figures 6 and 0). Then, with a backward movement, the second part 27 interacts with the sleeve (for instance with the base thereof; this step is not shown in the figures), thus bringing it again to the initial position (figure 8) with respect to the inner rod 4A. With a backward movement again, the first part 26 returns in initial position (this step is not shown; the initial position corresponds to figures 4 or 5 and 7).

In some embodiments (see in particular figure 4), the pushing means 25 provide for a first translation actuator 28, for instance a pneumatic cylinder, carrying on its movable member a second translation actuator 29, for instance a further pneumatic cylinder. The first part 26 is associated with the first actuator 28, while the second part 27 is associated with the second actuator 29.

According to preferred embodiments, the receiving module 23 comprises a receiving area 30 for receiving the packs from the unloading station 15, a plu- rality of support elements 31 for supporting the packs, where the packs preferably hang, an area 32 for handling the packs on the support elements 31 , and a movement path 33 for moving the support elements 31 from the receiving area to the handling area 32. Pairs of support stems 24 for supporting the packs, as described above, are defined on the support elements 31 . Hereunder, the sup- port elements 31 will be also called "hanging elements", as they practically define a support for the packs onto which the packs are constrained at an upper constraint, so that they hang.

The path 33 comprises a segment in which an accumulation area 35 for the packs is defined and along which the hanging elements 31 are directed so that the packs are transverse, with reference to the pack width, to the feeding direction in the same segment. More in particular, in this example the path 33 has a first rectilinear segment 33A with the receiving area 30, and a second segment 33B with the accumulation area 35. Adequately, the part of the movement line with the unloading station 15 is rectilinear and parallel to the first recti- linear segment 33A, wherein the direction for pulling out the packs from the unloading station 15 to the receiving area 30 is substantially orthogonal to these segments; the second segment 33B is preferably rectilinear and parallel to the first segment 33A.

As it is shown, the movement path 33 for the hanging elements 31 is a closed loop (the movement direction is indicated by the arrow H) and the handling area 32 is arranged downstream of the accumulation area 35 and upstream of the receiving area 30, so that a hanging element 31 returns towards the receiving area 30 after having passed through the handling area 32. An inspection area 36 is preferably provided downstream of the receiving area 30 and upstream of the accumulation area 35. In this inspection area monitoring means can be provided (not shown n the figures) such as a video camera, for pack quality control. In this inspection area the transiting hanging elements 31 are directed so that the packs are parallel, with reference to the pack width, to the feeding direction along the path in this area.

Analogously, also in the handling area 32 the hanging means 31 transiting there are directed so that the packs are parallel, with reference to the pack width, to the feeding direction along the path in this area, so as to facilitate an operator O who must handle them.

To transfer a pack more easily, in the receiving area 32 the hanging element 31 receiving the pack is directed so that the received pack is parallel to the direction according to which the needles 14 arrive into the unloading station 15.

Adequately, means are therefore provided to change the orientation of the hanging elements 31 along the path 33. The hanging elements, in fact, can rotate about vertical axes Z and they meet along the path mechanical traps or adequately shaped obstacles (not shown in the figures) that force them to rotate around Z by a preset angle (for instance 90°) so as to take the above described orientations, as it will be better understood from the description below.

Figure 14a is a top view of a scheme of the receiving module, a variant of that illustrated in the other figures. In this scheme, the handling area 32 is at the end of the side of the path 33 related to the second segment 33B where the ac- cumulation area 35 is provided and not the inspection area 36.

In general, due to balancing reasons, in each version may be advantageous to dimension the lengths of the various segments of the path 33 so that the number of hanging elements that can be arranged in the segments moving from the receiving area 30 towards the handling area 32 is equal to the number of hanging elements that can be arranged in the returning segments from the handling area 32 to the receiving area 30.

Preferably, for instance with reference to figure 14A, the overall segment of path developing from the receiving area 30 to the handling area 32 is of substantially equal length to the overall segment of path developing from the han- dling area 32 to the receiving area 30.

In this example, the path 33 provides for an overhead guide 37, which is supported by a frame 38 and along which the hanging elements 31 slide. Preferably, each hanging element 31 comprises a carriage 39 sliding on the overhead guide 37 and provided with a toothed wheel 40 coupled to a belt or chain 41 moving along said guide, which is in turn operatively connected with return toothed wheels 42, at least one of which acts as a motorization.

A preferably vertical stem 43 develops from the carriage 39 downwards, rotating with respect to the carriage with respect to its own axis Z. A head 44 is arranged along this stem for receiving the packs from the unloading station 15. On this head two support stems 24 are arranged for the pack of bags. These stems 24 are preferably arranged on a bar 45 developing from said head; the stems 24 (in the described example, the bodies 24B of the stems carrying the tubes 24A which directly support the pack of bags and which are pulled out from these bodies 24B together with the pack), if adequately released, can translate on the bar 45 to allow their reciprocal distance to be adjusted, so that they can be correctly aligned with the needles 14.

Adequately, a device may be provided for preventing removal of the pack from the support stems 24, such as a guillotine 46 sliding vertically, preferably automatically actuated, in front of the stems 24 and at an adequate distance therefrom so that the bags of the pack cannot be removed.

In preferred embodiments, vertical translation means are provided for the hanging elements, so as to facilitate the operator at least during the handling step, these means moving the hanging packs from the top downwards, i.e. moving them towards for instance a container arranged in the handling area and suitable to receive the packs removed from the hanging elements by the operator in this area.

These vertical translation means comprise for instance a sliding coupling between head 44 and stem 43, with corresponding means, not shown in the figure, for blocking the head on the stem that can be deactivated, and a translation cursor 47 associated with a vertical translation actuator 48 interacting with the head 44 releasing the coupling thereof with the stem and translating the same head on the stem. Means of this type are present both in the receiving area 30 to raise (arrow K in figure 15) the head 44 with the pack with respect to the receiving place, and in the handling area 32 (arrow T in figure 16) to lower the head with the pack downwards, facilitating the operator during handling/removing operations, for instance to move the pack towards a container C).

In other embodiments, the vertical translation means can be arranged on- ly in the handling area 32 to facilitate the operator. For instance, the hanging elements with the packs may be always at the height of unloading from the unloading station 15, i.e. at the height in the receiving area 30 and, once arrived in the handling area 32, the operator can, if necessary, raise the hanging element with the pack, center it on the container C and lower it at the desired height to facilitate removal of the pack with the tubes 24A.

The toothed wheel 40 of the carriage 39 of each hanging element is coupled to a clutch mechanism 50 so that when this clutch mechanism 50 is actuated, the wheel 40 is substantially integral with the carriage and a movement of the chain or belt 41 entails a movement of the carriage 39, i.e. of all the hanging element, along the guide 37, while when the clutch mechanism 50 is deactivated, the toothed wheel 40 is substantially free to rotate with respect to the carriage so that this latter (and therefore all the hanging element) is fixed on the guide also during the movement of the belt or chain 41 .

Each carriage 39 is preferably provided with a control 5 A-5 B for actuat- ing-deactivating the clutch mechanism 50 belonging to a preceding carriage 39; therefore when the carriages are lined up adjacent to one another, in the accumulation area, the actuating/deactivating control 51A-51 B of a carriage interacts with the clutch mechanism of the preceding carriage, deactivating it (5 B indicates for instance a strut interacting with a button 51 A of the preceding carriage, suitable to deactivate the clutch mechanism); at the beginning of the accumulation area there is a stop (not shown in the figures) for the first carriage of the accumulated line, than can be actuated and deactivated, so that the last carriage arriving into the accumulation area abuts against the second to last carriage of the line, stopping but being subjected to the traction force of the chain 41 as it has no a back control for actuating/deactivating its clutch mechanism; adequately, the clutch mechanism 50 is adjusted so that the traction force of the chain 41 is such to win the clutch force of the mechanism, thus driving into rota- tion the toothed wheel of the last carriage, with the consequent movement of the same chain.

The operator, according to the needs, actuates the control blocking the first carriage of the line, allowing the movement thereof towards the handling area. In this case again there is a stop (not shown in the figures) that can be actuated and deactivated for the carriage arrived into the handling station, so that the operator can manage the handling and unloading steps in an optimum way.

The receiving module 23 of the apparatus according to the invention can be also different than that described; it is also possible that there is no receiving module, using directly an operator or a robot on the unloading station 13 for unloading the packs.

Analogously, the receiving module described above, even if optimal from a synergy viewpoint for an apparatus like that described above, can be also used in other apparatuses for moving packs, different than the apparatus de- scribed herein.

It is clearly that the invention also relates to a method or a system for forming packs of bags providing for inserting, on at least one needle in vertical or almost vertical arrangement, a plurality of plastic bags, and subsequently overturning the at least one needle bringing it into a horizontal or almost hori- zontal arrangement, and subsequently removing this bag from the at least one needle in horizontal or almost horizontal arrangement.

The functionality of the technical solution upon which the invention is based relates to the fact that the needles can rotate from the sub-vertical position (for instance 15° from the verticalness) described above, to a practically horizontal position (90° + 15°) in the stations after the forming stations, so that the pack of bags is in substantially vertical position, supported by the (now horizontal) needles. In this position it is extremely more easy to transfer the pack of bags from the pair of needles onto which the single bags have been collected to a pair of receiving stems (arranged with the same center-to-center distance as the holes on the bags) on storing elements, for instance the hanging elements, sliding on conveyors of any kind.

An embodiments of the cited needles, facilitating and making the transfer of the packs safer, is that described, wherein in each needle a sliding sleeve is provided, allowing the needle to elongate during the unloading step (transfer to the hanging elements), thus ensuring the correct alignment between the needle and the receiving stem.

From an operational point of view, it is furthermore provided that the member for removing the pack, once ended its active stroke, returns into the start position, thus engaging the rotating needles, that from the horizontal position are pushed into the start position (90° + 15°), where they are held for instance through adequate magnets (not shown in the figures).

The operation of transferring the packs from the needles in forming position (vertical or almost vertical) to another hanging system with horizontal support stems allows to significantly simplify the production plant of the Wicket type or the like, reducing the length of the collection chain, wherein it is also possible to group in one single station the operations of overturning the needles and transferring the packs.

The needles able to rotate may be advantageously mounted on a conveyor belt with three stations, anchored on a platform with a U-shaped mechanical structure, in which one of the long sides acts as an axis around which the arms of the needles rotate, while the opposite long side acts as a support for the arm (taken into position by a magnetic system) while the connecting side is integral with the conveyor belt. With this configuration the segments of axes of rotation of the needles in the active area of the three stations are therefore coaxial and allow the needles to move longitudinally from one to the other platform. This solution allow a quick adjustment of the space between the needles when it is necessary due to the size of the sacks to be produced.

From the point of view of management of the apparatus, it is possible to accumulate in a receiving module, i.e. practically a storage with variable capacity, the packs produced and ready to be packaged and sent, allowing the operators to perform these activities with times that are practically independent of the production rates of the welder, thus making ergonomic and less onerous the operation of packaging the packs and allowing a quality control also in the form of TV recording of the working steps. The rotation of the hanging elements around the guide allows to move the packs towards each other in the direction of the thickness thereof in the accumulation area, with limited bulk and therefore with high loading capacity for each meter of length of the guide.

In the unloading station each carriage is positioned frontally to allow the operator to close the sealing means for the packs (tubes/bars).

From a point of view of the vertical position of the carriage with the pack it is possible to vary the height thereof to optimize the insertion into the boxes.

It is understood that what illustrated above purely represents possible non-limiting embodiments of the invention, which may vary in forms and arrangements without departing from the scope of the concept on which the invention is based. Any reference numbers in the appended claims are provided for the sole purpose of facilitating the reading thereof in the light of the description before and the accompanying drawings and do not in any way limit the scope of protection of the present invention.