Device for forming containers produced continuously from a tubular wrapper and unit for packaging the containers

A device (8) for forming containers (2) produced continuously from a tubular wrapper (3) fed along a substantially vertical direction of advance (A). The device has at least one support carriage (8a) movable along a respective closed path having at least one active segment parallel to the direction of advance (A). The carriage (8a) supports a sealing base (11) able to be associated to a first lateral face of the tubular wrapper (3) at a sealing region (Z) of the wrapper (3). A contrasting element (14) is removably associated to the support carriage (8a) and movable between a first closed position in which it approaches the base (11) and abuts against a second lateral face of the tubular wrapper (3) opposite to the first lateral face at the sealing region (Z), and a second position in which it is movable away from the base (11).

CROSS REFERENCE TO RELATED APPLICATION

This application is a National Stage entry of International Application Number PCT/IT2005/000208, filed Apr. 13, 2005, and claims priority of Application Number RM2004A000235 filed May 13, 2004, in Italy. The disclosures of the prior applications are hereby incorporated herein in their entirety by reference.

TECHNICAL FIELD

The present invention relates to a device for forming containers produced continuously from a tubular wrapper fed along a substantially vertical direction of advance. The present invention further relates to a unit for packaging the aforesaid containers in which the forming device finds advantageous use.

BACKGROUND ART

The invention is in the sector of packaging containers of incoherent material, generally containers of liquids for human consumption. Such containers are produced in continuous fashion from a tubular wrapper fed along a substantially vertical direction. The tubular wrapper is filled with incoherent material and subsequently sealed and cut along transversal seal lines which define the individual containers.

As is well known, the wrapper material, generally constituted by heat-sealable paper material, is continuously unwound from a reel towards a folding device adapted to join opposite longitudinal edges of the wrapper to each other. The tubular wrapper is then advanced along a vertical path through a filling unit. The filling unit delivers the incoherent material inside the tubular wrapper through an upper opening of the tubular wrapper. Downstream of the filling unit is a forming device provided with heated bars adapted to perform a series of seals, transverse to the longitudinal axis of the tubular wrapper. The heated bars are mounted on a fixed support structure and are movable only to approach each other. In this way, the container containing the incoherent material is defined between two consecutive seal lines. Lastly, a cutting member positioned downstream of the forming device separates the containers from each other by a transverse cut along the seal line.

The known packaging units described above have important drawbacks, which are linked mainly to the forming device.

It should be noted that the heated bars are positioned at opposite sides of the tubular wrapper and movable to approach each other to press the region to be sealed along a transverse direction to the direction of vertical motion of the tubular wrapper. Because of the movement of the bars, the tubular wrapper is braked intermittently, causing considerable damage to the seal region. During the motion of the wrapper, the bars slide on the wrapper causing incorrect seals and the damage to the sealed area.

The prior art discloses devices able to overcome the aforementioned problems by providing bars movable along the path of the tubular wrapper.

As is described for example in European patent EP1125847, the forming device provided with movable bars is constituted by two adjacent support frames having respective belts movable along a closed path. The tubular wrapper is actuated through the belts, at a rectilinear segment of the closed path, parallel to the direction of actuation of the wrapper. Each belt bears a plurality of carriages which are movable along the path. Each carriage bears a heated bar adapted to abut on the surface to be heated of the tubular wrapper. In this situation, when the carriages are positioned at the rectilinear segment, the bars of each pair of carriages abut against each other pressing the region to be sealed of the tubular wrapper. The pressing operation is then performed while each pair of carriages is maintained in motion along the direction of actuation of the tubular wrapper. The device described above has important drawbacks, although it solves the problem of avoiding any relative sliding between the bars and the wrapper.

These drawbacks are linked mainly to the structural complexity of the sealing device and of the overall size presented thereby. It should be noted that the structure constituted by two frames, each of which has a belt, is very bulky, further considering that each belt has respective motion transmission member. Moreover, it should be considered that each pair of carriages must necessarily be in synchrony during the sealing operation to make the pressing between one bar and the other efficient. To maintain the correct positioning of the carriages, electronic means are provided for controlling and adjusting. Such means are sometimes highly complex and have an excessive cost of construction. Consequently, the presence of means for controlling and adjusting the belts causes high costs for the production and/or commercialisation of the known devices.

SUMMARY OF INVENTION

An object of the present invention is to solve the problems noted in the prior art by proposing a forming device and a unit for packaging containers able to solve the aforementioned drawbacks of the prior art.

In detail, the object of the present invention is to provide a device for forming containers having a simple, economical, reliable structure, with small size which is able to seal tubular wrapper following the advancing path of the wrapper.

DETAILED DESCRIPTION OF THE INVENTION

With reference to the accompanying figures, reference number1globally designates a unit for packaging containers2produced continuously from a tubular wrapper3. It should be specified thatFIG. 1schematically shows, by way of example, the unit1in which some technical details have been removed for better clarifying the general structure of the unit1.

In detail, the unit1is constituted by means4for feeding a continuous strip3aof paper material from which the tubular wrapper3is obtained, as shall be better explained hereinafter. The feeding means4are constituted by a reel5of the continuous strip3aand by transmission rollers5aadapted to feed the strip3aalong a predefined path. Downstream of the feeding means4is a forming member6able to join opposite longitudinal edges of the continuous strip3ato define the tubular wrapper3. The forming member6, which is not described and illustrated in detail, is constituted by a series of sliding guides, respectively twisted to overturn at least one longitudinal edge of the strip3aon the other and seal the edges together. The tubular wrapper3is then fed along a vertical direction A of the respective path, at a member7for filling the wrapper.

In greater detail, the tubular wrapper3has a respective upper opening corresponding to a portion of the belt3a, not yet sealed, in which the incoherent material is dispensed. The filling member7is constituted by a dispensing nozzle7apositioned at the opening of the tubular wrapper3and engaged with a respective conduit for containing the incoherent material. For example, if the incoherent material is constituted by a liquid, the nozzle7adispenses the liquid inside the tubular wrapper filling the latter from the lower portion to a predetermined height. Thus filled, the tubular wrapper passes by a forming device8which constructs the containers2from the tubular wrapper3.

The forming device8, illustrated in detail inFIG. 2, is constituted by at least one support carriage8amovable along a respective closed path. This path has substantially elliptical shape and is constituted by at least one active segment that is parallel and coincident with the vertical direction of advance A of the tubular wrapper3, and by a passive segment opposite to the active segment.

Advantageously, the device8has a plurality of carriages8aactuated along the path by respective actuating means10as shall be better described below. In detail, each carriage8ais constituted by a pair of shoes9associated with a respective sealing base11at opposite ends11aof the base. As further illustrated in the detail ofFIG. 5andFIG. 6, each shoe9has a body12having substantially parallelepiped conformation in which is defined an inner surface12aengaged to one of the ends11aof the base11and an outer surface12bopposite to the inner surface12a. At the outer surface12bof the body12are operatively associated a plurality of sliding elements13, preferably constituted by rotatable casters13a. More in detail, each body12has three casters13arotatable about respective axes, transverse to the development of the active segment of the path. At least two of the three casters13aare advantageously aligned to each other along the development of the path, whilst the remaining caster is positioned below the first two. Each body12also has an upper portion12cpositioned above the base11in which is obtained a seat12dadapted to house a contrasting element14.

As mentioned above, between each shoe9a base11is provided having substantially parallelepiped conformation and developing along a respective longitudinal dimension, transverse to the aforementioned active segment. The sealing base11is adapted to be associated to a first lateral face of the tubular wrapper3, at a seal region Z of the wrapper3. It should be noted that the seal region Z, which is illustrated more clearly inFIGS. 11 through 13, is constituted by a segment that is transverse to the longitudinal development of the tubular wrapper3where a first lateral face of the wrapper3is joined with a second lateral face opposite to the first lateral face. In this way, each individual container2is defined between two seal regions Z. The sealing base11has a first surface15able to be associated to the first lateral face of the wrapper3and having longitudinal development corresponding to the seal region Z. Preferably, the first surface15has respective sealing means, not further described in detail. For example, said sealing means can be constituted by an electrically heated lamina, a radio frequency emitter, or an ultrasound emitter.

As is better illustrated inFIG. 4, each sealing base11also has a second surface16opposite and parallel to the first surface15. From the second surface16, a first and a second projecting element17,18are provided side by side to each other. The first projecting element17has an insertion pivot17awhich extends transversely to the planar surface of the second surface16below the base11. The second projecting element18has an opening18aobtained on the element18and oriented below the base11.

As previously mentioned, each body12of the respective shoes9has an upper portion12cin which is obtained the seat12dable to house the contrasting element14. Each shoe9has a contrasting element14movable between a first closed position in which the contrasting element14approaches the base11and abuts on the second lateral face of the tubular wrapper3at the seal region Z, and a second position in which the contrasting element14moves away from the base11.

In detail, each carriage8ahas two contrasting elements14associated at respective opposite ends15aof the first surface15and each of which extends from the respective end15ato a median portion of the first surface15. The contrasting elements14of each carriage8aare movable symmetrically between the first position, in which they are side by side along a same longitudinal axis (see for exampleFIGS. 4 and 5), and the second position in which they face each other and are transverse to the longitudinal development of the first surface15(see for exampleFIG. 3).

In yet more detail, each contrasting element14includes a bar19having a respective active surface19awhich, in the first position of the contrasting element14, is able to abut on the first surface15of the base11. Advantageously, the active surface19aof the bar19can also have known sealing means, previously described in exemplifying fashion. The pressure exerted by the active surface19aof the bar19and of the first surface15of the base11determines the pressing of the seal region Z of the tubular wrapper and the consequent sealing thereof.

Each bar19also has an end portion20positioned at an end11aof the base11. In particular, the end portion20is inserted rotatably in the seat12dobtained in the upper portion12cof the respective body12. In still further detail, the end portion20is inserted in the upper portion12cby means of a through pivot20a, in such a way as to make the bar19rotatable about an axis that is perpendicular to the planar development of the first surface15of the base11. Additionally, at each end portion20of the respective bar19, a sliding element13is positioned above the bar19. This sliding element, too, is constituted by a caster13arotatable about a respective axis, transverse to the longitudinal development of the respective bar19.

The means10for actuating the carriages8ahave at least one support guide22to guide the carriages8aalong the closed path. Advantageously, as shown in the accompanying figures, two support guides22are provided, parallel and at a distance from each other, each of which is associated to each shoe9of each carriage8a. In greater detail, each guide22includes a rail extending along a substantially elliptical path, corresponding to the development of the closed path. The casters13aof each body12rotate on the respective rail, in such a way as to slide along the close path.

As shown in detail inFIG. 5, each rail is interposed between the sliding elements13in such a way that for each body12of the shoe9two casters13aare positioned aligned to each other on an upper surface of the rail and that a third caster13ais placed on a lower surface of the rail. With reference toFIG. 3, it should be noted that each rail includes a primary rectilinear portion23parallel to the direction of advance A of the tubular wrapper and corresponding to the active segment of the closed path. Moreover, each rail has a secondary rectilinear portion24opposite and parallel to the primary rectilinear portion23and two arched junction portions25between the primary23and secondary24rectilinear portions. The secondary rectilinear portion24and the arched portions25constitute the passive segment of the closed path. Each guide22also has a side panel26positioned at the primary rectilinear path23and able to be engaged with the bar19to actuate the contrasting elements14between their first and second position.

In detail, the side panels26, each of which is associated with a respective guide22, include a contrasting surface27, twisted and facing the carriages8a. In yet closer detail, as better shown inFIG. 4, each contrasting surface27has a first portion27aparallel to the planar development of the first surface15of the base11, and a second portion27bconsecutive to the first portion27and transverse to the planar development of the first surface15. Each caster13aengaged on the respective end portion20of the corresponding bar19rotates on the contrasting surface27to rotate the bar19between the first and second position. Advantageously, when each caster13aassociated to the respective bar19rotates on the first portion27aof the contrasting surface27, the corresponding contrasting element14is in the respective second position in which the contrasting element14is detached from the respective base11. During the advance of the carriage8athe caster13aassociated to the respective bar slides on the twisted portion rotating the contrasting element14about the pivot20a, until the caster13ais able to slide on the second portion27bof the contrasting surface27b, and the corresponding contrasting element14is positioned in the respective second position in which the contrasting element14approaches the base11.

The actuating means10also have a first motor member28to actuate the carriages8aalong the active segment of the close path and a second motor member29to actuate the carriages8aalong the passive segment opposite to the active segment. As shown inFIG. 7, the first motor member28has a transport element30whose longitudinal extent is parallel to the active segment and associated with a motor31. Both the motor31and the transport element30are interposed between the guides22. Preferably, the transport element30is constituted by an auger32rotatable about a longitudinal axis parallel to the active segment.

More in particular, the auger32includes a cylindrical body having an outer surface in which is obtained a helical cavity32a. When a carriage is positioned in the active segment, the insertion pivot17aof the first projecting element17of the respective base11is inserted in the helical cavity32a. Advantageously, as a result of the rotation of the auger32, the pivot17aslides along the helical cavity32adriving the base11and the respective pair of shoes9along the active segment corresponding to the longitudinal development of the auger32. The auger32is set in rotation by the motor31through appropriate motion transmission members31a, not further described in detail. For example, said transmission members31can include a pair of pulleys associated respectively with the drive shaft and to an end of the auger and linked to each other by a belt.

It should be specified that the accompanying figures show an auger32having the respective helical cavity32awith constant pitch, in order to maintain constant the actuation velocity of every carriage8aalong the active segment for the same angular velocity of the auger32. However, a helical cavity32awith non-constant pitch may be provided to vary the actuation velocity of the carriages8a. For example, at one end of the auger32placed at a final portion of the active segment, the helical cavity32amay have a pitch (distance between a point of the cavity and the next symmetrical point) that is greater than the rest of the auger32. In this way, when the carriage8aslides along the greater pitch of the cavity32a, the carriage8aincreases its speed because of the greater distance of the pitch.

Alternatively, variations in the size of the pitch of the helical cavity32amay be provided to quicken or slow the travel of the carriages8ain the active segment.

In a further alternative embodiment shown inFIG. 9, the first motor member28is constituted by a first and a second transport element30and30′ set side by side. In particular, the two transport elements30and30′ respectively include a first and a second auger32and32′ extending longitudinally, mutually parallel and parallel to the active segment. The first and the second auger32and32′ have, respectively, the helical cavities32aand32a′ with mutually different pitch, i.e., one of the cavities has a greater distance between one point and its next symmetrical point that the other helical cavity.

The bases11belonging to respective carriages8ahave the first projecting element17positioned at the first or at the second auger32and32′. In this way, the base11of a carriage8ahas the respective pivot17aassociated to the helical cavity32aof the first auger32and the subsequent carriage8ahas the respective pivot17aassociated to the helical cavity32a′ of the second auger32′. In this way, every carriage8acan be actuated along the active segment at a different speed from the subsequent and from the previous carriage8a.

Alternatively, a first and a second auger32and32′ can be provided, with respective helical cavities having the same pitch. The two augers are actuated independently of each other and with different velocity to differentiate the velocity of advance of each carriage8a.

With reference toFIG. 8, the second motor member29has at least two pulleys33positioned mutually side by side, each pulley being positioned at an arched portion of junction25. The pulleys33rotate about respective axes, mutually parallel and parallel to the planar development of the first surface15of each base11. The pulleys33are respectively associated to a belt34positioned substantially along the passive segment to transport each carriage8aalong the passive segment. The second motor member29also has at least one transmission roller35of the belt34positioned between two pulleys33to distance the belt34from the first motor member28.

In detail, the belt34has an inner surface34aable to abut against the pulleys33and an outer surface34bopposite to the inner surface34aoriented towards the guides22and associated to the transmission roller35. As shown inFIG. 8, the belt34slides along a substantially two-lobed closed path defining the passive segment. Additionally, the belt34has a plurality of engagement pivots36, mutually equidistant and extending from the outer surface34bof the belt34(also visible inFIG. 4). The transmission roller35which can abut against the outer surface34bof the belt34, has respective seats able to receive the engagement pivots36during the actuation of the belt34. The engagement pivots36are advantageously shaped complementarily to the openings18aobtained in the respective second projecting elements18of the bases11and able to be inserted into the openings18a.

In detail, when one of the carriages8ais positioned at the passive segment and then placed at the belt34, an engagement pivot36is inserted into the respective opening18aand drives, by the motion of the belt34, the respective carriage8aalong the passive segment. Advantageously, as shown inFIGS. 2 and 7, the device8also has a plurality of walls37each of which is associated between two successive shoes9for abutting to a flank of the tubular wrapper3transverse to the first and second lateral face. In particular, the walls37have substantially plate-like development and their planar development is transverse to the planar development of the first surface15of each base11. Preferably, a pair of walls37are provided, respectively associated between each carriage8aand the adjacent carriage8a.

As shown inFIG. 7, each wall37has a first end37apivotally engaged to a corresponding shoe9at the second surface16of the base11, and a second end37bopposite to the first. The second end37bhas a pivot, slidable within a slot whose development is parallel to the closed path and which is obtained in a projection of the respective shoe9. In this way, the adjacent carriages8acan approach or move away from each other making the pivot in the slot.

Each pair of walls37then abuts respective opposite flanks of the tubular wrapper to give a substantially parallelepiped shape to each individual container2during the sealing of the region Z. Moreover, by virtue of the walls37associated to the shoes9, it should be noted that the walls37are positioned abutting the opposite flanks of the wrapper3only when the shoes are positioned along the active path.

The forming device8, lastly, has means38for cutting the tubular wrapper3, which are operatively active at the seal region Z to obtain the individual containers. The cutting means38has at least one separator device39illustrated in detail inFIG. 10and positioned downstream of the active segment relative to the direction of advance A of the tubular package3. The separator device39is constituted by a support frame40secured to a load-bearing structure41of the forming device8(seeFIG. 2). The support frame40is constituted by an upright40adeveloping above the tubular wrapper3transversely to the direction of advance A of the tubular wrapper3. On the upright40ais secured a motor42, not described further in detail, operatively associated with an arm43movable transversely to the direction of advance A between a first position in which the arm43moves from the tubular wrapper3and a second position in which the arm43approaches to the seal region Z of the wrapper3. In particular, the arm43has substantially longiform conformation and has a first end43apositioned at the motor42and associated thereto by a transmission member44. The transmission member44includes a connecting rod-crank kinematic mechanism with three pulleys44aset in rotation by the motor42by a belt44b. The first end43ais pivotally engaged to two of the three pulleys44a(seeFIG. 10) at an off-centre point of the pulleys.

In this way, the rotation of the pulleys44adetermines the rectilinear reciprocating movement of the entire arm43between the respective first and second position. The arm43also has a second end43b, opposite to the first end43a, in which is a housing seat of a blade45whose longitudinal development is parallel to the longitudinal development of the first surface15of each base11. Advantageously, when the arm43is in the second position, the blade45is positioned above the seal region Z in order to cut it longitudinally. After the transverse cut of the wrapper3, the blade45abuts against the first surface15of the base11positioned below the blade45. It should be noted that, when the blade45approaches the wrapper3to cut the seal region Z, the contrasting elements14positioned on the respective base11are moved away from the first surface15. In this way, the arm43can freely approach the tubular wrapper3without being hindered by the contrasting elements14.

In accordance with an alternative embodiment shown inFIG. 11, the separator device38is positioned downstream of the guides22along the direction of advance A. Two arms43and43′ are provided, facing each other and with each of them having the respective blade45,45′.

Still with reference toFIG. 11, it should be noted that the tubular wrapper3is positioned between the two arms43,43′ which are actuated in mutually independent fashion to move closer or farther away from each other. Advantageously, when the arms43,43′ are movable to approach each other, the respective blades45and45′ abut against each other in such a way as to cut the tubular wrapper3transversely at the respective seal region Z.

In the embodiment variant ofFIG. 12, the second end of the arm43′ has a contrasting support46, adapted to abut against the blade45of the other arm43. The contrasting support constitutes a fixed support of the blade45and is advantageously provided with a recess (not shown in the figure) inside which is housed the blade45.

FIG. 13shows an additional embodiment variant of the separator device38. Only one arm43as described above is present and it is positioned at the active segment above the side panels26. Additionally, in accordance with this alternative solution, the bars19of the contrasting elements14have a through opening47which extends longitudinally along each bar19. When the bars19both approach the first surface15of the respective base11, the through openings47of the bars19are mutually side by side and aligned in such a way as to define a single opening whose longitudinal development matches the longitudinal development of the seal region Z. The respective base11has a recess48obtained on the first surface15and developing along the longitudinal development of the surface15. Advantageously, as shown inFIG. 13, the recess48is placed at the openings47of the bars19when the bars19abut against the region Z to be sealed. When the contrasting elements47abut against the region to be sealed Z, the blade45can be inserted into the openings47of the bar19. In this way, the blade45passes through the openings47and cuts the region Z longitudinally until it inserts itself into the recess48.

The operation of the packaging unit1and of the respective forming device8, described above in prevalently structural sense, is the following.

With reference toFIG. 1, the continuous strip3ais fed from the respective reel5towards the forming member6of the tubular wrapper3. The forming member6folds at least one longitudinal edge of the continuous strip3aon the other and longitudinally seals the region of superposition of the edges. In this way, the tubular wrapper3is defined and fed along the vertical direction A by appropriate members. The tubular wrapper3fed vertically has a respective upper opening defined by the respective longitudinal edges, not yet sealed. Advantageously, the filling member7delivers the incoherent material inside the tubular wrapper3through the upper opening. In this situation, the tubular wrapper3positioned vertically is filled only up to a certain height. The tubular wrapper3thus filled passes at the forming device8along the active segment of the closed path.

Starting from a carriage8awhich passes from the passive segment to the active segment, it should be noted that the first surface15of the base11abuts against the first lateral face of the wrapper3. The respective pivot17ais positioned in the helical cavity32aand by the rotation of the auger32the pivot slides along the cavity32adriving the respective base11and the shoes9along the active segment. The sliding elements13of the respective shoes9slide along the primary rectilinear portions23of the respective guides22at the same velocity of advance as the tubular wrapper3. When the shoes9are at the side panels26, the respective contrasting elements14are positioned in the corresponding first position.

In particular, when the carriage8aarrives at the side panels26, each sliding element13positioned on the respective bar19slides on the first portion27aof the contrasting surface and subsequently, following the twisted profile of the contrasting surface27, it advances until reaching the second portion27b. In this way, the sliding elements13positioned on the bars19move from a position in which they rotate on the first portion27aabout an axis that is parallel to the planar development of the first surface15of the base, to a position in which they rotate on the second portion27babout an axis that is perpendicular to the planar development of the first surface15. Consequently, the bars19that are associated to the respective sliding elements13rotate about the through pivot20afor positioning above the second lateral face to press the second lateral face. Because of the pressing of the bars19against the base11, the lateral faces of the wrapper3are sealed and the sealing region Z obtained during the continuous advance of the wrapper3along the direction A.

When the carriage8aadvances outside the side panels26, the contrasting elements return to the second position in which the bars19are moved away from the base11. Advantageously, moreover, a spring50(shown inFIG. 4), positioned about the pivot20a, determines the return of the contrasting element14in the second position. It should be noted that advantageously, multiple carriages8aare positioned simultaneously on the active segment in such a way that at least two successive carriages8aare at the side panels26. The tubular wrapper2can be sealed simultaneously in multiple parts or individually at different times.

With reference to the embodiment in which the pitch of the cavity32ais variable, successive carriages8amove faster in the initial segment. In this way, a displacement of the respective seal regions Z which are mutually approached. Advantageously, because of this longitudinal squashing of the tubular wrapper3the individual containers2are deformed to a specific shape. For example, during the longitudinal squashing of the wrapper3, the flanks of the wrapper3are deformed towards the exterior in such a way as to adhere to the walls37. In this situation, the containers2are formed with parallelepiped shape in which the flanks constituted opposite lateral walls.

In the embodiment ofFIG. 9, each carriage8ais associated in alternating fashion to one of the two augers32,32′. Each pair of carriages8a, which are respectively associated to the first or to the second auger32,32′, move with different velocities. For example, if the helical cavities have different pitch (or if the helical cavities are identical but the respective augers are fed in mutually independent fashion) the carriage8aassociated to the auger32having the helical cavity32awith greater pitch (auger fed at higher velocity) moves faster than the carriage8athat precedes it in such a way as to move the seal regions Z to each other and to define the squashing of the container2. When the contrasting element14return in the second position, the carriage8ais positioned at the separator device38. At this point the arm43is actuated towards the base11until the respective blade45abuts against the seal region Z to cut the same. As a result of the transverse cut of the tubular wrapper3, the blade45bears on the first surface15of the base11and subsequently the arm43is moved away from the base11. Advantageously, the containers2previously filled and formed are obtained as a result of the transverse cut.

In the embodiments illustrated inFIGS. 11 and 12, the tubular wrapper3is made to advance sealed outside the guides22to allow the two arms43to approach each other and to cut the wrapper along the region Z to define the containers2.

In accordance with the embodiment ofFIG. 13, the separator device13is positioned above the side panels26and the arm43approaches the wrapper3when the contrasting elements14are still pressing and sealing the wrapper3. The blade45passes through the openings47obtained on the bars19to cut the region Z whilst it is sealed. Advantageously, at the end of the sealing operation, i.e., when the contrasting elements14move away from the tubular wrapper3, the container2is already detached from the remainder of the wrapper3. Once the transverse seal is completed, the carriage8apasses from the active segment to the passive segment. The pivot17areaches the end of its travel in the helical cavity32aand the base11is positioned at one of the two pulleys33. One of the engagement pivots36positioned on the belt34is then inserted into the opening18adriving the carriage8aalong the passive segment in the two arched portions25and in the secondary rectilinear portion to return the pair9to the active segment.

The present invention solves the problems noted in the prior art and achieves the proposed object.

First of all, the forming device8allows accomplishing the sealing and the forming of the containers2during the travel of the tubular wrapper3. Because of the movement along the active segment of the carriages9in synchrony with the advance of the wrapper3along the direction A, the bars19and the respective base11do not rub on the wrapper3. Advantageously, the seals in the region Z and the forming of each individual container2are accomplished correctly.

It should also be noted that the described device has very small bulk and a particularly simple structure. This advantage is due to the presence of a single pair of guides22adapted to support and guide the shoes9.

Advantageously, using the contrasting elements14movable on the respective bases11, additional elements positioned in front of the forming device8and adapted to press and seal the wrapper3are eliminated. For this reason, the forming device8, in addition to having reduced size allows a marked reduction in construction and commercialisation costs and easy accessibility in case of failure.

Lastly, another advantage is provided by the ability to give a particular shape to the container2during the sealing operations.