METHOD AND MACHINE FOR PREPARING

GROUPS OF PRE-PACKED PRODUCTS, SUCH AS

ROLLS OF PAPER, FOR PACKAGING IN BAGS

DESCRIPTION Technical field

The invention refers to a machine and method for packaging groups of prepacked products in varying formats, such as groups of paper rolls or other products coming from one or more packaging machines from which the packages can be discharged with the roll axes arranged horizontally or vertically, in bags obtained from thermoplastic film or sheet unwound from a reel. Background art

In the field of paper converting, for the production of packages of toilet paper rolls, kitchen towel rolls, paper napkins and the like, it is custom practice to produce individual packages or groups of pre-packed products, such as groups of paper rolls, wrapped in a thermoplastic sheet. A plurality of said wrapped groups or packages of articles- are subsequently grouped together and ^' wrapped ^" into bags, i.e. bagged, each bag being usually formed by a further thermoplastic film or sheet, and each bag containing a predetermined quantity of individual packages, each package being formed by a predetermined number of orderly arranged individual products.

A packaging and bagging device for packaging and bagging rolls of tissue paper is disclosed in EP-A-1, 306,308. An automatic bundling machine including a packaging section and a bagging section is disclosed in US-A-4,679,379. In known devices a plurality of packages are introduced into seats of a chain con- veyor, which forms groups of pre-determined packages, each package having a pre-determined dimension. Said group of packages is then moved on an elevator, and from there into a wrapping tunnel or mandrel, i.e. a device which forms a tubular wrap of thermoplastic film around the group of packages. The thermoplastic tubular film is transversely cut and sealed to form a bag around each group of packages.

A problem that currently exists in the bagging lines of known type is due to the fact that when the format of the product packages to be prepared for bagging varies, many of the line components have to be replaced, resulting in long downtimes and involving difficulties in storage of the components to be re-

placed.

Objects and summary of the invention

According to a first aspect, an embodiment of the invention is aimed at remedying these problems of the known devices, with a solution which, as the format of the product packages varies, requires simple, easy and rapid adjustments, which can be performed automatically, if required, via the use of a few servo controls that can be controlled from the machine control panel, appropriately configured for the purpose.

According to a different aspect, an object of an embodiment of the inven- tion is to provide a bagging device, which has a compact and simple layout.

The invention also concerns a method for bagging packages of products which is more efficient than prior art methods. In a preferred embodiment, the invention concerns a method which allows handling of packages of variable formats with easy and quick adjustment interventions on the packaging ma- chine.

In an embodiment, the invention concerns a method for bagging groups of packages of pre-packed products of varying format, in bags obtained from thermoplastic film or sheet unwound from a reel, including the following steps:

- feeding correctly oriented packages along a pre-set number of rows; - discharging and grouping on an elevator a preset number of packages from each said rows, while the packages upstream the ones discharged on said elevator are retained to stop the entire flow of upstream packages;

- raising the grouped packages to the height of a bagging station;

- transferring said grouped packages in said bagging station and introducing said grouped packages in a thermoplastic tubular wrapping film;

- forming a bag with said tubular wrapping film.

In an embodiment of the invention, the packages grouped on said elevator are moved by said elevator to the height of said bagging station and transferred from said elevator into a wrapping tube of said bagging station. In a pre- ferred embodiment, the packages are lifted from a lower position, at the level of an advancement conveyor, to an upper position, where a wrapping tube or mandrel of a bagging machine is arranged. Arranging the bagging station underneath the advancement conveyor is not excluded.

In a possible embodiment of the invention, each bag can include a single layer of packages. In a further embodiment of the invention the packages are grouped according to a plurality of superposed layers, such that each bag includes two or more superposed layers of packages, each layer including one or more packages. In a preferred embodiment the layers are piled up in a superposed configuration on an elevator and then transferred into the bagging station.

When sets of packages are grouped according to a plurality of superposed layers, said layers can be formed on a first elevator, on which two or more layers of packages are formed. The elevator is then moved towards the bagging station such that the layered packages are transferred, e.g. by means of a pusher, from the elevator into the bagging station, e.g. into the wrapping tunnel of the bagging station. According to a different embodiment, said superposed layers of packages are transferred from a first elevator to a second ele- vator and said second elevator moves said superposed layers of packages at the height of said bagging station.

In a preferred embodiment, said packages are fed along a distribution conveyor, preferably in a spaced apart relationship. From said distribution conveyor said packages are distributed according to a plurality of substantially parallel rows. In an embodiment of the invention said distribution conveyor is pivoted around a preferably approximately vertical swivelling axis arranged at an inlet side of said distribution conveyor, such that an outlet side of said distribution conveyor is sequentially brought into alignment with a plurality of substantially parallel channels to sequentially feed said packages in each said channel and form a row of packages in each said channel.

In a preferred embodiment, said rows are advanced along a direction substantially aligned with a main direction of advancement of said distribution conveyor. Since the distribution conveyor oscillates in order to distribute the packages in each said rows, the direction of advancement of said distribution conveyor is variable. A main direction of advancement is defined as an approximately mean direction between the various angular positions, which the distribution conveyor can assume when distributing said packages in said rows. The invention can typically be used to package and bag rolls of tissue paper, such as toilet rolls, kitchen-towel rolls or the like. In general, the invention

can be applied for packaging rolls of wound web material. If the products to be bagged are rolls of wound web material, according to a preferred embodiment said rolls are oriented with their axes in a substantially vertical position and advanced along a substantially horizontal direction from said distributor con- veyor to said advancing conveyor.

In a preferred embodiment, the method of the invention includes the following steps:

- forming said rows along an advancement conveyor;

- temporarily stopping said rows at the end of said advancement conveyor; - in each row, defining a leading group of packages to be discharged, said leading group including a pre-set number of packages in each row;

- temporarily retaining the packages upstream said leading group of packages;

- while said upstream packages are temporarily retained, discharging said leading group of packages from said advancement conveyor;

- releasing and advancing said upstream packages towards the end of said advancement conveyor.

In a preferred embodiment, said leading group of packages is discharged from said advancement conveyor on a first elevator and after said leading group of packages has been discharged from said advancement conveyor onto said first elevator, said ^" upstream packages are released and advanced towards the end of said advancement conveyor.

Further embodiments and advantageous features of the method according to the invention are described here below with reference to the drawings and are set forth in the appended claims.

According to a further aspect, the invention concerns a machine for bagging groups of packages of pre-packed products of varying format, in bags obtained from thermoplastic film or sheet unwound from a reel, including:

- a distribution conveyor, which pivots on a swivelling axis, arranged to re- ceive said packages;

- downstream of said distribution conveyor, an advancement conveyor with an inlet end and an outlet end, said advancement conveyor being provided with adjacent channels, said distribution conveyor being arranged and

controlled to feed said packages sequentially into said channels, said packages forming adjacent rows travelling in said channels along said advancement conveyor;

- a stoppage member for temporarily stopping the rows of packages at the end of said advancement conveyor;

- a first elevator for collecting the rows of packages at the outlet of said advancement conveyor and move said packages to a bagging station;

- a retention device arranged along said advancement conveyor at a distance from said outlet end, for cyclically retaining on said advancement conveyor a package of each row positioned immediately upstream of the package(s) to be discharged on said first elevator when said stoppage member is de-activated.

The arrangement of said retention device is such that it retains a package in each row of said advancement conveyor such that the flow of packages is interrupted even though the advancement conveyor continues to move. The continued motion of the advancement conveyor causes discharge of the most advanced packages in each row, i.e. the leading group of packages, once the stoppage member has been de-activated. The advancement conveyor, therefore, feeds the leading group of packages on the elevator arranged at the exit side of said advancement conveyor while the upstream packages are prevented from advancing.

According to a preferred embodiment of the machine of the invention, a feeder is arranged upstream of said distribution conveyor, for feeding correctly oriented and spaced apart packages to the inlet of said distribution conveyor. In a preferred embodiment, said feeder is adjustable according to the format of said packages. For example it can include adjustable side walls and/or distanced conveyors, the mutual distance of which can be adjusted according to the height of the packages.

In a preferred embodiment of the machine according to the invention, also said distribution conveyor is adjustable according to the format of said packages.

In an advantageous embodiment, said channels on said advancement conveyor are adjustable according to the format of said packages and of said

groups of packages to be bagged. They can be adjusted as far as the width and the total number of channels is concerned. I.e. the number of rows of advancing packages can be modified, as well as the transversal dimension thereof.

Said bagging station can include a pusher for transferring said groups of packages into said bagging station, for example into a wrapping tunnel to which a wrapping film or web is fed from a reel.

According to a preferred embodiment, the distance between said retention device and the end of said advancement conveyor is adjustable. In this manner the number of packages for each bag can be set as required. If more packages have to be placed in each bag, the distance between the outlet end of the advancement conveyor and the retention device is increased. Such distance is decreased if a smaller number of packages are required in the bag or in each layer of the bag.

In an embodiment of the invention, said retention device includes a member movable from a retracted position, in which it does not interfere with the packages advancing along said advancement conveyor, and an active position, in which it interferes with the packages advancing along said advancement conveyor. Said movable member can include a retention bar, which is lifted from a position underneath the advancing surface, defined by the active branch of said advancement conveyor, to an extracted position, in order to lift a package from said conveyor and temporarily retain it while the conveyor can continue to advance the packages downstream said retention device. The retention bar can include a retention edge, for example it can be shaped in the form of an L-profile, the edge forming an abutment surface for the packages. In a preferred embodiment the bar co-acts with an upper pinching bar, such that a package is temporarily retained between said two opposing bars for the time required for discharging the downstream packages from the advancement conveyor on the elevator.

In a modified embodiment, said retention device can include a moving member which is moved from an upper position, clear of said packages, to a lower position, in which it interferes with the packages and retains the foremost package immediately upstream the leading group of packages, i.e. those packages which have to be discharged on the elevator and moved into the bagging station. A lower retention bar moving from a lower inactive position to an upper

active position is preferred, since it does not require spacing the packages in each row.

In an embodiment of the invention said first elevator is arranged and designed to take at least a first position at the level of said advancement conveyor, to receive packages from said conveyor and a second position at the level of said bagging station, to discharge said packages from said first elevator towards said bagging station. In a preferred embodiment, said elevator is provided with a conveyor, such as a belt conveyor. The belt conveyor is activated to eject the packages from the elevator and/or to abut the packages along a wall placed on a side of the elevator.

To correctly align the packages on the elevator, in an embodiment of the invention an abutment wall is arranged on the downstream side of said first elevator, against wall which said packages are stopped and aligned when they are transferred on said first elevator. According to the design of the machine, the abutment wall can be fixed or movable.

In an embodiment of the invention, the stoppage member includes an abutment wall integral with said first elevator, extending downwards therefrom at the upstream side thereof and facing said advancement conveyor. With this arrangement, when said first elevator moves up to transfer the layer of pack- ages to the height of the bagging station, said abutment wall stops the flow of packages on said advancement conveyor, such that no packages falls down from the advancement conveyor. Once the elevator is brought at the level of the advancement conveyor again, the abutment wall is clear of the packages, and the leading group of packages, downstream of the retention device, can be discharged on the first elevator.

In a different embodiment, said stoppage member includes a movable interception device arranged at the outlet end of said advancement conveyor.

In an embodiment of the machine which is designed to wrap layered groups of packages, the machine includes a second elevator, arranged down- stream said first elevator in the direction of advancement of said packages. The advancement conveyor, said stoppage member, said retention device, said first elevator and said second elevator are arranged and controlled such that when a required group of layered packages has been formed on the first elevator, said first elevator is placed at the same height as the second elevator and said group

of layered packages is transferred from said first elevator to said second elevator, so that while the second elevator transfers the group of packages to the bagging station, the first elevator is brought at the level of the outlet end of said advancement conveyor for receiving a new group of packages. Further features and embodiments of the machine according to the invention are described here below with reference to the attached drawings and are set forth in the appended claims. Brief description of drawings

In the drawings, in which the same or similar parts are indicated with the same reference numbers:

- Fig. 1 and 2 are schematic side elevation and overhead views respectively - of a bagging machine in a first embodiment for packaging one single layer, of product packages;

- Fig. 1a illustrates an enlarged side elevation of a component of the machine as per the preceding figures;

- Figs. 3, 4 and 5 illustrate a side elevation of the final part of the machine as per the preceding figures during successive work phases;

- Figs. 6 and 7 are side elevation and overhead views respectively of a bagging machine in the version with layering device, for packaging several layers of product packages;

- Figs. 6a and 6b illustrate an enlarged side elevation and overhead view respectively of components of the machine as per figures 6 and 11 ;

- Figs. 8, 9 and 10 illustrate a side elevation of the terminal part of the machine as per figures 6 and 7 during successive steps of a work cycle; - Figs. 11 and 12 are side elevation and overhead views respectively of a device for feeding a bagging machine, in the simplified version alternative to that of figures 6 and 7;

- Figs. 13, 14, 15, 16 and 17 illustrate a side elevation of the terminal part of the machine as per figures 11 and 12, during successive work steps; - Fig. 18 illustrates a side elevation of a possible embodiment of an elevator for the machines as per figures 6 and 11 ;

- Figs. 19 and 20 illustrate respectively, in perspective, a product package as it arrives at the machine as per figures 1 and 2 and how several packages of

this type are bagged by said machine;

- Figs. 21 and 22 illustrate respectively, in perspective, a product package as it arrives at the machines as per figures 6, 7 and how several layered packages of this type are bagged by said machine. Detailed description of embodiments of the invention

Figure 19 illustrates a typical package C1 of rolls of paper arranged with their axis horizontally in several rows and in several layers and with the edges L of the heat-sealable wrapping sheet positioned on the ends of the hollow core of said rows of rolls, so that in the heat sealing phase of said edges between a pair of ordinary conveyors with vertical axis, the rolls undergo compression in the axial direction of greatest resistance to deformation: ■ These ^packages- Ct: ■- must usually be fed to a bagging machine? with the axes of.the rolls positioned a vertically as jn Figure 20 and must be arranged in several parallel rows, for example in three rows, so that one or more packages per row, e.g. two pack- ages per row, can be bagged inside the packaging bag S obtained from a heat- sealable plastic film which is formed into a tube by means of a longitudinal seal,- not illustrated; and closed -at the opposite ends -by means of corresponding^ transverse seals T1 and T2.

A packaging of this type can be produced with the machine according to the invention, which is now described with reference to the Figures from 1 to 5 in a first embodiment. In these Figures, 1 indicates a tubular mandrel or wrapping tunnel with a horizontal axis, on which a continuous strip 102 of thermoplastic material runs longitudinally, unwound from a reel 2 controlled by unwinding means, not shown, controlled by a guide pulley 3 also of known type. As it runs on the wrapping tunnel 1, the strip 102 is folded and then formed into a tube and its longitudinal overlapping edges are sealed by a known longitudinal sealing means 4, so that said wrapping tunnel produces a continuous tunnel of plastic material which, correctly timed, undergoes, by known means schematically indicated by the opposite arrows 5, positioned downstream of said wrap- ping tunnel 1 , a double transverse seal and is cut in-between the seals to close the end of the filled bag and the beginning of the new bag and to separate the filled closed bag, which can thus be moved away, from the new bag being formed.

The packages to be bagged are arranged as described below on an eleva-

tor 6 which in a step of its work cycle is at the same level as the wrapping tunnel 1, so that packages arranged on the elevator 6 can be pushed into and through the forming wrapping tunnel 1 and beyond it by the action of a known horizontal pusher 7, which pushes a portion of the bag- forming film along with the pack- ages inside the film downstream of the sealing and cutting means 5 which, properly timed, act as soon as said pusher 7 is retracted, so as to produce the bag S illustrated in Figure 20, inside which the packages will be packed tightly and blocked, exploiting the deformability and consequent elasticity of the packages on the horizontal plane, both lengthwise and crosswise, due to the ar- rangement of the rolls with their vertically oriented axes.

In an embodiment, the packages C1 (see. Figure 1.9), are, initially- arranged . with their roll axes horizontal and move in single file-.in the.direction of the arrow F. For example they come in this position from an upwardly arranged packaging machine (not shown). From Figures 1 and 2 it can be seen that the machine according to the invention comprises first positioning means 8 which feed the packages C1 forward, subjecting them to a transverse: rotation of 90?-, so as to; position them with- their; roll axes-vertical; said means comprise; for example; a< pair of adjacent belt conveyors 108, 208 which run in the same direction and at the same speed, the conveyor numbered 208 being of limited width and hori- zontal, while the wider one 108 slopes longitudinally downwards, so that while the package C1 performs a downward movement on this conveyor, the same is supported on one side by the horizontal conveyor 208 which causes it to perform the desired rotation of 90°.

At the outlet of the positioning conveyor 8, the packages C1 reach a hori- zontal motor-driven conveyor 9, which feeds said packages to a pair of reciprocally parallel conveyors 10, one above the other and appropriately motor-driven. Said conveyors 10 form a feeder, which feeds said packages at the right distance from one another (i.e. suitably distanced one from the other) onto the initial end, i.e. the inlet end of a rectilinear type horizontal belt distribution con- veyor 11 , which is pivoted about a substantially vertical axis 111 and is provided with lateral guides 211 and with appropriate motor. Said distribution conveyor 11 is provided with swivel means, not shown, which causes the distribution conveyor 11 to oscillate about the axis 111 so that its outlet end can be cyclically positioned in different horizontal positions, for example in three different

positions as shown in Figure 2, so as to feed the packages C1 in rapid succession into three substantially parallel channels12. The channels have an adjustable width according to the format (e.g. the transverse dimensions) of the packages Cl Each channel is laterally defined by lateral guides 12 positioned with appropriate adjustment means, not shown, on one single advancement con- veyor13. In an embodiment of the invention, the advancement conveyor 13 is formed by a single wide belt, as shown in the drawings. However, in an alternative embodiment said advancement conveyor can include a plurality of parallel narrow belts. The advancement conveyor 13 is driven by appropriate motor means, which causes the packages Cl to advance and to stop against a stopping, member. In an embodiment of the invention said stopping member includes a vertical wall 106 integral with the movable frame of the elevator 6.

In an embodiment of the invention, an intermediate stretch or portion of the upper branch and of the lower branch of the-conveyor 13, as-better high- lighted-also-in-Figure-1arruns-on,-groups-of parallehidIe-rollers-t47 15-positioned ^~ at the vertexes of hypothetical isosceles trapeziums positioned one inside the other and with the smaller base facing upwards, so as to form in the upper branch of said conveyor a small transverse aperture through which a retention or stop bar 16 can operate, which can be raised and lowered by an actuator (not shown). Said bar co-acts with a parallel upper bar 17 which, as the format of the packages C1 varies, can be adjusted in terms of distance from the conveyor 13, so as to substantially skim the tops of the packages moving on said conveyor. These latter components 14, 15, 16 and 17 are fitted on a carriage 18, the sides of which run on horizontal guides 19 and which is connected to manual or automatic adjustment means so that, as the format of the packages C1 or the format of the final package S varies, the bars 16 and 17 can be positioned immediately upstream of the group of packages, which each channel of the conveyor 13 has to transfer to the elevator 6 for forming a single package S. In a preferred embodiment the elevator 6 is of the type in which the working surface is formed by a horizontal conveyor 206 driven in the same direction as the conveyor 13. Downstream of the elevator 6 a vertical fixed wall 20 is provided, above which the film 102 passes towards the wrapping tunnel 1. As best shown in Figure 2, the terminal part of the conveyor 13 and laterally to the

elevator 6, there are lateral guides 21 provided with means for adjusting the reciprocal distance as the format of the packages to be bagged varies.

The machine according to this first embodiment operates as follows. At the end of one work cycle and the beginning of the next work cycle, the elevator 6 is in the raised position as shown in Figure 1 with its wall 106 stopping the flow of packages fed into each channel 12 of the conveyor 13. If, as in the example shown in Figures 19 and 20, three rows of packages have to be cyclically fed into the packaging bag S with two packages per row, the unit consisting of bar 16 and the counter bar 17 is positioned at the level of the third package starting from the one that touches the stop plate 106. Thus, a leading group of packages, including two packages per channel 12, is formed, said leading group of packages is discharged on the elevator 6 as described later on and then transferred to the bagging station 1-5.

While the pusher 7 terminates its work cycle and retracts and while closing and separation of a bag S full of packages downstream of the- wrapping tunnel is completed, the command is given for lifting of the-bar 16 as in Figure ^' 3; so that the latter stops the third package in each channel 12, lifting it from the upper branch of the conveyor 13 and blocking it against the upper bar 17 while, correctly timed, the elevator 6 is lowered onto the same plane as the conveyor 13 so as to receive from said conveyor 13 the leading group of packages (two per row) positioned downstream of said bars 16, 17 and convey them against the fixed wall 20, as shown in Figure 4. The leading group of packages C1 downstream of bars 16, 17 are moved on the elevator 6 by the very motion of the advancing conveyor 13, while the flow of packages C1 upstream of the leading group is prevented by bars 16, 17. In a preferred embodiment, belts 206 (forming a conveyor on the upper surface of the elevator 6) move the packages C1 forward against wall 20.

Subsequently, while the pusher 7 has in the meantime returned to the retracted cycle start position, the elevator 6 is raised to the same plane as the lower wall of the wrapping tunnel 1, as shown in Figure 5, so that the groups of packages arranged on the elevator 6 can then be transferred by the conveyor 206 of said elevator and by the pusher 7 through the wrapping tunnel 1 for a subsequent bagging phase. The bagging step as such is known and not described in detail. In this same phase, the machine returns to the condition of

Figure 1 , since following lowering of the stop bar 16 the packages C1 temporarily retained by the bars 16, 17 are released and the rows of packages fed by the conveyor 13 can advance until they are stopped against the high wall 106 of the elevator 6.

5 While the pusher 7 completes its work cycle and then returns to the rest position and while the means 5 operating downstream of the wrapping tunnel 1 close the full bag S as shown in Figure 20 and separate it from the next bag closed at the front, the machine prepares for a new work cycle.

It is clear that,. as the format of the packages to be bagged varies, only ad-

10 justment operations have to be performed, thus avoiding complex, costly and lengthy operations for replacement of machine components, as required by the known machines. Advantageously,a reduction of machine downtime is achieved and, if required, all or some of the adjustments can be made automatically, by providing suitable servomotors or actuators, which move the parts and compo-

15. nents of the packaging line which require adjustment.

Figures 6 to 10 show- a further embodiment of the ^" machine according to the invention. In this embodiment, the machine includes a layering device, which is used when several packages have to be stacked on one another in a layered condition and in said condition inserted in the wrapping tunnel 1 of the 0 bagging station.

The need for layered packages is particularly felt when the packages are of limited height, for example those C2 of the flat rectangular type illustrated in Figure 21 , with the rolls arranged with their axis in a vertical position and with the overlapping and reciprocally sealed edges L of the package now positioned 5 ^■ -: on the lateral surface of the end rolls.

As illustrated in the example of Figure 22, three layers of packages C2 as in Figure 21 must be arranged on top of one another in layers, for example in three layers, and this pre-arranged layered group of packages must be inserted through the aforementioned wrapping tunnel 1 for formation of the packaging 0 bag S as in Figure 22.

To form said bag, if necessary with packages different from those illustrated in Figure 21, with the same advantages as those mentioned previously for the machine as per Figures 1 to 5, the machine shown in Figures 6 and 7 comprises an initial conveyor 8' fed with packages C2 that move in the direction

of the arrow F (see also Figure 21). Said first conveyor positions the packages C2 with their larger dimension in the feed direction, for example by acting pushing said packages C2 against a lateral initially inclined guide 308'.

' At the outlet of the positioning conveyor 8', the packages C2 are intro- duced between the pair of motor-driven parallel conveyors 10 positioned one above the other that feed said packages at an appropriate distance from one another to the exchange conveyor 11 , which in turn distributes said packages in the various channels 12 of the conveyor 13, which moves the packages forward in several adjacent rows and is constructed in the same way as previously de- scribed with reference to Figures 1 and 1a. In this case, however, at the end of the conveyor 13 an interception device 22 is provided, which on command is positioned in front of the flow of packages to stop them and which, correctly timed, can be neutralised to permit the feed of said flow of packages. Good results have been obtained with a square-shaped device with one side facing downwards and pivoting with the end of the other side on an axis 122 (Fig.6a), which can beiieight-adjusted as the format of the packages varies, and which ^' is ^" connected to oscillation means such that the side of the same facing downwards can be lowered or raised, on command, as described below.

The bar 16 and the upper counter bar 17 are adjusted so that they are po- sitioned above the initial part of the package C2 which follows the one stopped by the aforementioned interception device 22. Downstream of said device 22 there is a pair of parallel motor-driven rollers 23 positioned one above the other, the lower one of which is at the level of the conveyor 13 and is in a static position, while the upper one can be height-adjusted if the format of the packages varies. The rollers 23 rotate in a direction to feed the packages coming out of the conveyor 13 at a speed equal to and/or appropriately higher than that of said conveyor 13.

Downstream of the pair of rollers 23 is a first elevator 24 formed of a plurality of parallel belts 124 which, on command, can be operated by motor means (see below) for feeding the packages forward and which terminate downstream in a comb-like arrangement, so that the vertical teeth of a comb 25 connected to raising and lowering means, not shown, can be positioned between them.

At the beginning of each cycle, the elevator 24 is on the same plane as the

conveyor 13 and the comb 25 is in a raised position, so as to protrude through the belts 124 and above said elevator at a height sufficient to stop a layer of packages C2. Downstream of the elevator 24 there is a second elevator 6 similar to elevator 6 in Figures 1 and 2, with the fixed wall 20 downstream. Other parts of the machine shown in Figs. 6 and 7 similar to those shown in Figs. 1-5 are not disclosed and reference is made to the description of the previous embodiment.

The machine shown in Figures 6 and 7 operates as follows (see Figs. 6, 8, 9, 10). As illustrated also in Figure 8, correctly timed with intervention of the bar 16 which stops the second package C2 against the upper bar 17, the interception device 22 is raised and the head package (i.e. the leading package C2) is transferred by the advancement conveyor 13, which remains active, and by the thrust rollers 23 onto the first elevator 24. In this phase the belts 124 of the first elevator 24 can be maintained in motion to ease advancement of theφackages C2 on the surface of the elevator 24. After the first package C2 has been positioned on the elevator 24, the conveyor belts 124 can be deactivated.

Subsequently the interception device 22 moves back down and the bar 16 is lowered so that the next package C2 is positioned against the device 22. According to a proper time sequence, the first elevator 24 moves down one step, which is preferably equal two or slightly greater than the height of a package C2. Then a second package is fed onto the elevator 24 and the cycle is then repeated until three packages C2 have been stacked on the first elevator

24, as shown in Figure 9.

When the second and third package C2 are stacked on the first elevator 24, the action of the thrust rollers 23 is decisive as they move the packages at the outlet of the conveyor 13 forward to ensure that they stop against the comb

25. In these steps the bar 16 moves up and down cyclically and the interception device 22 is also lowered and raised so that, cyclically, a set of packages (one for each channel 12 in the example shown) comes out of the thrust rollers 23, for stacking on the auxiliary elevator. It is not excluded that a different number of packages C2, for example two packages C2, are fed each time from the advancement conveyor 13 onto the elevator 24. In this case the bars 16, 17 are adjusted a step backwards, such that they act on the third package C2, i.e. leaving the first and second package C2 in each row free to be discharged from

the conveyor 13 on the stack being formed on the elevator 24.

When the three layers of packages C2 have been stacked on the auxiliary elevator 24, the same is raised to the position shown in Figure 10 and the comb 25 is lowered, so that with subsequent activation of the belts of the conveyor 124 on elevator 24 and the of the conveyor of the second elevator 6, the grouped pile or stack of layered packages C2 passes onto the main elevator 6 and stops against the fixed wall 20, as illustrated by the broken line in the same Figure 10.

Subsequently, while the main elevator 6 moves up and the pusher 7 is ac- tivated to insert the layered group of packages in and beyond the bagging station 1 , 5, as in Figure 8, the comb 25 is raised and the first elevator 24 is activated to receive from the advancement conveyor 13 a first package C2 of a next group of packages.Then the cycle described above is repeated.

It is understood that lateral guides, not shown, are provided for- controlling the layered group of packages on the auxiliary elevator 24 and on the main elevator 6. It is-clear-that also- in this- type of -machine, ^" as- the ^~ product ^~ format varies, only adjustment operations have to be performed and these can be easily automated.

With reference to the Figures from 11 to 17 a machine with. layering device is now described, in a simplified embodiment with respect to the one of Figures 6 to 10. In the embodiment of Figs. 11-17 layering of the packages is performed directly on a first elevator 6' similar to the first elevator 24 of the machine shown in Figs. 6-10 (see below). Said elevator 6' is also used to move the layered packages C2 from he level of the outlet of the advancement conveyor 13 to the level of the wrapping tunnel 1. Members and parts of the machine oi Figs: 11 to 17 which are equal or equivalent to those of the embodiment shown in Figs. 6 to 10 are indicated with the same reference numbers and are not described again. The structure of elevator 6' is similar to the structure of elevator 24 and includes comb-like belts, so that between the comb-like end of its belts, facing towards the wrapping tunnel 1 , the downward-facing teeth of a comb 25' can operate. In this embodiment the comb 25' is fixed rather than movable as comb 25 (Figs. 6-11).

In the example shown in Figure 18, the parallel belts 306' of the conveyor provided on top of elevator 6' or those 124 of the elevator 24 described previ-

ously can be such as to derive their movement from a motor 406 in a fixed position, by means of a belt 306 guided about another pulley 506 in a fixed position and about pulleys 606 that can be moved with said elevator and are sustained by it. It is understood, however, that the belts of the elevator 6' and those of the elevator 24 can be driven by any other suitable means, e.g. by means of a motor supported by the elevator itself:

From Figure 11 it can be seen that to limit the downtime between one cycle and the next one, the outlet of the conveyor 13 has been raised and moved nearer below the pusher 7, so that it is a short distance from< the height position^ of the wrapping tunnel 1 and to avoid interferences between said pusher 7 and the parts below it, said conveyor 13 with relative lateral guides 12 has been longitudinally inclined so that only its outlet is raised/ All 'the other components of the machines are the same as those described for the machinefin» Figuress 6- and 7. Operation of the machine as in Figures 11 and 12 is as follows (see Figs.

13^17). At the beginning of the cycle, the elevator 6' is at the lever of the outlet of the conveyor 13, so as to receive from the latter a first layer of packages G2 (in the example one package C2 for each channel 12), which stop against the comb 25', as shown in Figure 13. Subsequently the same elevator 6' is gradu- ally lowered by a step equal to or slightly greater than the height of a layer of packages, so that the various layers of packages are stacked or layered in succession on said elevator 6' by the pair of thrust rollers 23, while each layer is stopped by the stationary comb 25' arranged at the right distance, while the bar 16 and the stop device 22 are raised and lowered, in the correct time sequence as described previously with respect to the embodiment off Figs. 6-10.* The:.op- : eration sequence thus obtained is shown in the succession of Figures 14, 15, 16.

Once the layering has been completed, as illustrated in Figure 17, while the interception device 22 is in the low position and while the bar 16 returns to the low position, the elevator 6' moves up to the level of the wrapping tunnel 1 and the pusher 7 transfers the group of layered packages inside and beyond the wrapping tunnel 1. As soon as the packages have been discharged from the elevator 6', the latter is lowered to the level of the advancement conveyor 13 and the device 22 is raised to repeat the cycle, while the pusher 7 completes its

work stroke and then returns to the rest position to prepare for the next work cycle.

As the height of the packages to be bagged varies, adjustment means can be provided as for the preceding machine embodiment shown in Figures 6 and 7, or easy register means can be provided to modify the angle of said conveyor 13, so as to raise or lower the height of the outlet thereof, while the interception device 22 associated with said outlet can be kept at a constant height, like the counter bar 17 and the upper one of the motorised- parallel thrust rollers 23, while the lower ^' one of said « rollers follows- the movement of ^; the ^■ outlets of ' said conveyor 13, to which the cycle start height of the elevator 6 can be adapted via suitable means. It is understood that even if not illustrated, also in this embodiment of the invention lateral- guides are provided^ adjustable, according to format,; to control.the.flow. of products imthe. terminal part of the; conveyoπci 3- and: on the elevator 6', like those indicated by 21 in the machine of Figure 2. Also in this embodiment, as the product format varies, only quick easy adjustments-have to- be- performed which, if required, ^' carr be ^" easily automated. I ή all three described embodiments- of- the- machine^ the distributions-conveyor -φ1 can be kept still to feed a flow of products to only one of the channels of the feed conveyor 13 if it is necessary to produce packages S formed of only one row of packages C1 or C2 arranged in one or more layers.

The aforementioned thrust rollers 23 can be replaced by a pair of parallel conveyors positioned one above the other, similar to 10 but also shorter.

It is understood that the description refers to some preferred embodiments of the invention, to which numerous construction variations and modifications can be made, without departing- from the principle underlying the invention, as described above, as illustrated and as claimed below. In the claims, the references in brackets are purely a guide and do not limit the scope of the protection of said claims.