Field of the invention

The present invention relates in general to a horizontal packaging machine.

More in detail, the present invention relates to a horizontal packaging machine having a cut-sew group (commonly known as a "crimper ¹ '), which is height- adjustable, i.e., the mutual position of the two shafts supporting the respective tools (or spatula groups) which cut and weld the product pack to size are adjustable.

Prior art

Flowpack packaging is a type of packaging for food products. Flowpack packaging means a type of plastic packaging made with the aid of a horizontal packaging machine.

In a flowpack horizontal packaging machine, the individual products are transferred and advanced directly within a single packaging film, which is welded in three points: two transverse welds which define the two lateral (or front edge and back edge) edges of the pack and a longitudinal weld to achieve the closing of the pack.

Therefore, the flowpack packaging is made starting from a film that once folded to form a tube is filled with the product (or products) and passes through a cut-sew group which allows the making of the two transverse welds indicated above (the one at the beginning and the one at the end of the pack).

In particular, the longitudinal welding is formed in the lower portion of the pack by means of a series of pairs of heat-sealing wheels positioned upstream of the cut- sew group, the number of which varies according to construction choices.

The final product (i.e. the flowpack) is then obtained by means of two transverse welds, which close the tube pack at the two opposite edges with the product inside and separate the pack made and finished from the next pack being formed.

The packaging film is arranged to form a tunnel to surround and envelope the product to be packaged. The film is formed by a single continuous web wound on a feeding reel and on which the different packs, all of the same size, are made. In particular, the reel is made from a continuous packaging film in which the different packs are printed in an aligned sequence on one side. Normally, the inner side of the packaging film, i.e. the side in contact with the product, is made of a suitable food-grade material.

Each pack will be the same size and display the same information (e.g. product name, manufacturer's logo, list of ingredients, product images, etc.), and the machine is calibrated to divide the packs so that the cuts are made in a predetermined portion in which there is no writing or images, but there could be a possible pattern or a monochromatic portion dedicated to welding and cutting. Therefore, the pack is repeated on the plastic film equal to itself with neutral interludes in which the welds and the cuts are made.

The flowpack packaging machine comprises a welding group, which has a continuous welder (typically located on the lower side in horizontal machines), which welds the two longitudinal ends of the packaging film, and a transverse heat-sealing head (or double head), which simultaneously welds the tail of one pack and the head of the next pack.

In particular, the cut-sew group makes a first weld, which closes the final edge of the pack, i.e. the tail, then makes the cut to separate the pack just made from the next pack being formed, and finally makes the second weld, which makes the initial edge or head of the second pack. In this manner, the individual wrappers are divided into separate packs.

Examples of flowpack (horizontal) packs are the packs frequently used for cakes, snacks, portioned packs of breadsticks, packs of crackers, individually wrapped sandwiches, candy, multiple packs of biscuits, chocolate bars, chocolates, etc.

Currently, the horizontal packaging machines are designed to process a limited series of lengths, i.e. a group of sizes in a given range of lengths which can be obtained with the same cut-sew group by setting the speed to achieve the desired pack length.

Furthermore, at present, if products with a different size must be packed, i.e. a length of the pack not comprised in the range obtainable with the cut-sew group mounted on the machine, the cut-sew group must be replaced on the machine itself, which operation provides disassembling the entire cut-sew group and refitting one with a different configuration of heat-sealing spatulas.

Alternatively, again in the prior art, the change of size (i.e. of length range) of the pack can be obtained by either increasing or decreasing the number of spatulas mounted on the cut-sew group present in the machine. However, this solution requires an adjustment and the intervention of a specialized mechanic. Furthermore, to implement such a solution, it is necessary to wait for the spatulas to cool down before disassembling them, and then it is necessary to wait for the still-mounted spatulas to warm up again before using them. Therefore this operation requires rather long machine stops.

As a function of the different types of products to be packaged, the cut-sew group, i.e., the one which performs the transversal welds and the cut which separates the packs and which is located downstream of the longitudinal welding group, has a different configuration, i.e. a different arrangement of the heat-sealing spatulas on the shaft. As mentioned above, this operation can be carried out by physically changing the cut-sew group or by materially changing the number and position of the heat-sealing spatulas on the same cut-sew group to modify the range of pack lengths which can be made.

In the current state, the tool replacement operation implies deadtime in which the machine is idle and non-operational. Furthermore, the size change operation (i.e., we repeat, the range of lengths which can be produced) requires the intervention of specialized manpower because it implies the replacement of a heavy element, e.g. weighing about 200-300 kg, or alternatively the variation (decrease or increase) of the number of spatulas on the same group, and in both cases also requires the making of different connections and calibrations before being able to use the machine again.

These disadvantages (downtime and the need for specialized interventions) make it necessary to find a solution which allows the horizontal packaging machines to be more flexible and easy to modify.

Therefore, in the prior art, the need is felt for a single machine which can be easily adapted to the different sizes required for packaging products.

Furthermore, there is a widespread need to be able to automatically adapt the packaging machine to the use of different packaging films, which are available and required in different thicknesses according to the customer, and to be able to appropriately adjust the mutual position of the tools as a function of their thermal expansion.

Summary of the invention

Horizontal packaging machines have a feeding system for the products to be packaged. Typically, such a feeding group comprises a conveyor belt on which the products to be packaged are fed in an orderly manner and with appropriate spacing, as well as an advancement group according to a tortuous path of the packaging film.

In particular, the solution suggested here relates to a particular portion of the horizontal packaging machine, i.e. the cut-sew group (the group which performs the transversal welds of the edges of the packs).

One of the purposes of the present invention sets out to achieve the possibility of making packs of different sizes, or rather, of making packs belonging to different ranges of length, using a single horizontal packaging machine and exploiting an "immediate" and "automatic" tool change which can be done substantially by anyone at the plant, without requiring the intervention of specialized personnel.

The solution suggested for the invention here envisages a tool change which does not require a long machine stop for the physical replacement of a cut-sew group or a change in the number of spatulas on the group itself but allows the machine to be adapted to the different length sizes of the pack to be obtained without any need to disassemble and physically replace the cut-sew group or some spatulas.

However, in the specific case, the main purpose that the invention intends to achieve consists in automatically and micrometrically adapting the mutual position of the parallel and facing shafts which support the processing tools to the different types (in particular by thickness) of packaging films to be processed and to the inevitable thermal expansion of the processing tools.

The latter purpose, in particular, is achieved by a horizontal packaging machine for packaging a product fed in a horizontal direction according to appended claim 1 which states that such a packaging machine comprises a cut-sew group for making on a packaging film transverse welds and a cut to close and separate each other two successive packs, wherein the cut-sew group comprises a plurality of cut and sew tools for making the transverse welds and the cut, wherein the transverse welds define the edges of the packs according to different packaging sizes for the product, wherein the cut-sew group comprises an upper shaft and a lower shaft driven in rotation independently by means of a respective upper motor and a respective lower motor, in which each shaft mounts on it the plurality of cut and sew tools and in which each cut and sew tool is composed of an upper tool and a corresponding lower tool, and wherein compensation means are present of the mutual distance between the two with micrometric adjustment of the distance to compensate for thermal expansion and use of packaging film of different thickness.

Additional detailed technical features of the horizontal packaging machine for packaging a product fed in a horizontal direction of the present invention are provided in the related dependent claims.

It is a purpose of the invention also only the cut-sew group itself as disclosed in appended claim 10, the shafts of which are mutually parallel and have a height distance which is adjustable to allow the cut-sew group of the invention to be used also with packaging films of mutually different thicknesses.

The height adjustment of the mutual position of the shafts of the cut-sew group of the invention advantageously serves to adjust the welding and cutting pressure also as a function of the temperature of the spatulas.

Again, other detailed technical features of the cut-sew group are contained in the corresponding dependent claims.

Brief description of the figures

Further features and advantages of the invention will be apparent from the reading of the following description provided by way of non-limiting example, with the aid of the figures shown on the accompanying tables, wherein: figure 1 shows a perspective diagrammatic view of a horizontal packaging machine according to the present invention; figure 2 shows different packaging sizes for the same product, all of which can be made using the horizontal packaging machine in figure 1 ; figures from 3 to 8 show some enlarged views of details of the product feed portion of the horizontal packaging machine in figure 1 ; figures 9-1 1 show construction details of the cut-sew group according to the present invention; figure 12 shows a perspective diagrammatic view of a horizontal packaging machine according to the present invention; figure 13 shows a side and partially cross-section view of the horizontal packaging machine of figure 12, in which the cut-sew group according to the present invention is visible; figures 14 and 15 show cross-section views of the horizontal packaging machine of figure 12, in which the cut-sew group according to the present invention is visible; figure 16 shows a view of the support structure of a cut-sew group according to the present invention; figure 17 shows a cross-section view of the support structure of the cut-sew group in figure 16; figures 18 and 19 show perspective views of the support structure of cut-sew group in figure 16; figures 20-22 show side cross-section views of the three tools of the cut-sew group according to the present invention which illustrate configurations of the heat-sealing spatulas for each tool; figures 23-26 show cross-section views of the horizontal packaging machine of figure 12, in which the cut-sew group according to the present invention is visible, and in particular, the compensation means of the mutual distance between the two shafts with micrometric adjustment to compensate for thermal expansion.

The parts according to the present description are shown in the drawings, where appropriate, with conventional symbols, showing only those specific details which are pertinent to understanding the embodiments of the present invention, so as not to highlight details which will be immediately apparent to those skilled in the art with reference to the description given herein.

Detailed description of the invention

The machine according to the present invention mounts a particular cut-sew group comprising a plurality of "cut and sew" tools designed for different lengths of packs or packets. Furthermore, the mutual distance (or position) in height between the shafts of the cut-sew group is adjustable in order to compensate for thermal expansion of the spatulas and to be able to use packaging films of different thicknesses.

In particular, the cut-sew group comprises two overlapping and facing rotating shafts which each carry the same plurality of cut and sew tools.

A cut and sew tool consists of one or more electrified heat-sealing spatulas arranged radially on the corresponding rotating shaft.

Transverse welding takes place by localized heating of the packaging film using a pair of electrified heat-sealing spatulas (an upper spatula and a lower spatula mounted on their respective tools) which periodically meet during shaft rotation and heat and weld the edges of the pack.

Finally, the cut-sew group further comprises cutting elements which are operated to separate two successive packs at the end of the first welding of the tail (or rear edge) of the finished pack and before the beginning of the second welding of the head (or front edge) of the pack being formed.

This cut is carried out by means of the aforementioned cutting elements, e.g. consisting of a blade and a counterblade arranged inside the electrified heat-sealing spatula. In particular, in various embodiments, the blade will be mounted between two facing and spaced welding elements of the spatula on the upper shaft, and the counterblade will be mounted between two facing and spaced welding elements of the spatula on the lower shaft.

With the machine according to the invention, each cut and sew tool can be used to make a plurality of packaging sizes, and in this case, the operating speeds, i.e., the rotation speed of the two shafts, should also be varied in addition to the configuration and setup of the machine. Furthermore, the plurality of cut and sew tools in a single cut-sew group gives the machine a high degree of flexibility and adaptability.

In this manner, the machine becomes flexible and can be used to package different products or different sizes of the same product without interventions requiring the assembly or disassembly of the entire cut-sew group or the assembly or disassembly of the spatulas on or from the same cut-sew group. The need to have a very flexible machine arises from the fact that some manufacturers need to make different packs for a single product to be put on the market, i.e. single, double or multiple packs, and they want to do this with a single machine. Therefore, the machine must have a configurable cut-sew group on board which can adapt to different sizes so that a large number of length ranges can be achieved.

Currently, as mentioned, the size (i.e. the length range) is changed by materially changing the entire cut-sew group (thus mounting a different cut-sew group on the machine, on a case-by-case basis, as needed) or by materially varying the desired number of spatulas present on the same group, requiring a machine stop which stops the production and needs the intervention of specialized personnel.

In contrast, the cut-sew group according to the present invention comprises various conformations which provide a plurality of cut and sew tools carried by two overlapping, facing rotating shafts. Each cut and sew tool comprises one or more electrified heat-sealing spatulas arranged radially on each rotating shaft of the cut- sew group.

The different cut and sew tools, composed of one or more spatulas, are mounted on a single cut-sew group and this allows to achieve the various sizes (for instance range of lengths) by selecting each time the cut and sew tool to be used inside the same cut-sew group mounted on the machine. Of course, the cut-sew group can comprise any number of tools (at least two) to achieve a variety of different sizes.

In the examples illustrated in the Figures, which show the preferred embodiment, the cut-sew group comprises three different cut and sew tools arranged spaced apart on respective shafts of the cut-sew group. In particular, on the upper shaft there are three upper tools and on the lower shaft there are the three lower tools aligned to cooperate with their corresponding upper tools.

In the machine of the invention suggested herein, the tool is changed by modifying the position of the cut-sew group, i.e. by making the entire cut-sew group translate transversely relative to the feeding direction of the product to be packaged and centering the desired cut and sew tool, e.g. the central tool, relative to the feeding position of the packaging film and the product to be packaged. Therefore, the cut-sew group is a mechanical element which moves, by virtue of a carriage or a slide, with a motorized command to arrange the desired upper and lower tools at the packaging film and the belt which feeds the products to be packaged.

In the embodiments considered and illustrated in the drawings, the cut-sew group comprises, as mentioned, three cut and sew tools (three upper and three lower), and this configuration allows maintaining approximately the same overall dimensions of the machine without impacting too heavily on the space occupied by the machine in a plant.

At the current state of the art, there are no horizontal packaging machines of this type on the market.

The entire horizontal packaging machine of the current invention will now be described in a preferred but not limiting embodiment of the invention.

The horizontal packaging machine comprises a conveyor belt which transports the products P to be packaged spaced out from each other according to a predetermined pitch and feeds them to the packaging machine in a forming group where it meets a reel of packaging film coming from a film unwinding group. The product passes through the forming tunnel in which the film spread and unwound from the reel is folded to form a tube which envelopes the product and is longitudinally welded by a group of pairs of heat-sealing wheels.

Downstream of the forming group there is the cut-sew group, in which the pack is welded and cut at its two ends in the transverse direction relative to the longitudinal weld made earlier. The cut-sew group welds the bottom (or tail or rear edge) of the first pack, then cuts and finally welds the head (or front edge) of the next pack.

The transverse welding tool (upper and lower) comprises one or more transverse welding spatulas, which are electrified and heat-activated spatulas.

Cutting elements, such as blades to cut and divide one pack from the next are present within each spatula, between the two facing welding elements.

Each upper and lower cut and sew tool is made, as a function of the set of pack lengths to be obtained, by one or more spatulas positioned to cut the packs to the correct and desired size. For example, with the packaging machine of the invention shown in the following drawings, the product feed rate is 1 ,250 products per minute to obtain a single pack, i.e., wrap a single product P.

The cut and sew tool for single packs is made of a plurality of spatulas spaced with a pitch to support these high numbers otherwise the tool with a single spatula would have to turn at an excessively high speed and reach excessively high accelerations.

At the moment, the cut-sew group in the current machines on the market creates a single size consisting of a set of lengths, and in order to change the size it’s necessary, as mentioned above, to change the entire group formed by two shafts or it is necessary to vary the number of spatulas by adding or removing spatulas.

These operations disadvantageously involve costs, machine stops, and the presence of a specialized mechanic who makes the change by disassembling the entire cut-sew group or by varying the number of spatulas according to needs.

Furthermore, at present, the size change cannot be carried out by a simple food industry operator, e.g. the operator who changes the reel of the packaging film or who checks the packs, because the right professional is required for this type of intervention.

Indeed, the specialized mechanic must disassemble the heavy cut-sew group, e.g. weighting up to one quintal, disconnect the various connections of the group with the machine, mount a new group, and reconnect the various cables and connections. Alternatively, the specialized mechanic must act directly on the cut- sew group by assembling or disassembling spatulas.

With the solution described here, the cut-sew group comprising a plurality of upper and lower tools is simply made to slide transversely relative to the advancement direction of the product by virtue of a carriage or slide to change the tool used to obtain a different size of the final pack.

In the embodiments illustrated in the figures, when the two shafts of the cut- sew group rotate and one of the three tools is working the other two tools also rotate integrally with the shafts but the spatulas of the other two tools are arranged offset relative to the spatulas of the tool in use so that when a spatula of the upper tool in use touches a spatula of the lower tool in use, the upper and lower spatulas of the other two tools are in such a position as not to touch each other, i.e., they are offset so as not to be in contact.

In the assembly of the different tools, there are offsets among the spatulas that make up the tools, i.e., if in the first tool the spatulas are positioned in the origin the first spatula of the second tool will have an offset relative to the origin and the first spatula of the third tool will have a further offset relative to the spatulas of the other two tools.

The two shafts that make up the cut-sew group have independent motors to achieve the initial alignment of the upper and lower tools. In particular, the alignment is done with a Homing technique, i.e., fine-tuning the positions of the tools on the two shafts. When the operator communicates to the machine through the operator panel the intention to work with one of the tools, the upper and lower tools must be aligned. This is done with the two independent servo-assisted motors which are mechanically synchronized.

Therefore, the solution according to the invention allows achieving an easy tool change to obtain a change which allows for a large number of length ranges of the pack. The cut-sew group is assembled once and then an adjustment is made with the two separate motors to align the tools to be used with each other and positioning of the cut-sew group to the feed line of the products to be packaged.

The packaging machine includes several motors for the various adjustments. In particular, there are two separate motors, one for each shaft on which the welding tools are mounted so that the shafts can turn independently during initial calibration. Normally, in regular operation, the two motors run synchronously.

The horizontal packaging machine of the invention further comprises a motor for positioning the cut-sew group and, finally, a motor for vertically moving the upper shaft.

Therefore, the spatulas of the selected welding tools are heated to perform the welding.

The welding tools are connected through connecting cables to an electrical collector group. Particularly, there are two separate collectors, one for each shaft, and each tool in the cut-sew group is independently connected to its respective collector. This allows each tool to be controlled separately so that only the tool in use is heated, leaving other tools unheated. In this manner, the collectors supply electricity to the spatulas through cables running through the shafts. The spatulas are heated by means of heating elements powered by electricity.

Furthermore, this separate connection allows to set a different temperature for each tool group. Furthermore, this separate connection allows to have a different temperature for the same group of tools in case a different packaging film with different thermal features or with a different thickness is used.

An electrical collector is a system which carries an electrical signal on a rotating shaft. The electrical collector inside presents rotating brushes and fixed brushes which generate a rotating sliding contact for transmitting the electrical signal.

The rotating collector is an electromechanical device which allows the transmission of power and electrical signals continuously from a static part to a rotating part or vice versa by maintaining constant temperatures on the spatulas by transmitting a signal from a thermocouple.

This solution, capable of continuous rotation, can significantly simplify the steps of mounting and assembly, avoiding the use of articulated systems with complex wiring with the possibility of damage and machine stop, drastically reducing maintenance interventions.

According to the transmission technology, the rotating collectors can manage power, data, or both in one combined solution.

The collector used in the solution suggested here can differentiate the temperatures of the various welding tools, allowing different temperatures to be selected for each tool of the plurality. Of course, while a tool is being used, i.e. the spatulas of the tool are heated, other unused tools remain cold. This also serves to minimize electrical energy consumption.

The collector used is devised so that it is all differentiable, so that only the spatulas of the tool in use are independently heated.

The support structure of the packaging machine requires the shafts carrying the cut-sew group to be supported by a frame and there are bearings to facilitate the rotation of the shafts. We now turn to a detailed description of an embodiment with the aid of the figures.

With reference to figure 1 , a horizontal packaging machine is indicated by reference M as a whole.

The horizontal packaging machine M comprises a feeding portion 10 and a welding portion 20, which in turn comprises a cut-sew group 22. The feeding portion 10 comprises a conveyor belt 12 for conveying the product to be packaged P in an orderly and cadenced manner, and a film unwinding group 14. In the film unwinding group 14, a reel 16 of packaging film F is unwound to go into the tunnel to pack the product P fed on the conveyor belt 12. Preferably, the conveyor belt 12 provides seats 12a obtained on the conveyor belt by virtue of transversal walls 12b created on the belt 12 and which allow the right spacing between the different products P. The packaging film F is wound on the reel 16 and through a series of return rollers 17 is unwound and kept in tension to feed the second portion of the machine, i.e., the welding portion 20.

The welding portion 20 makes the final pack and performs three welds, one longitudinal relative to the advancement direction of the product to be packaged P, and two transverse welds to separate the packs from each other. The transverse welds are the two welds that make the edges of each pack.

The solution of the invention described here focuses on transversal welding and employs a special cut-sew group 22 (also known as a "crimper ¹ '), which allows making packs of different sizes as will be better described below. The cut-sew group 22 can have different configurations according to the format and size of the product P to be packaged.

Figure 2 shows some possible packs all of which can be made with the machine according to the present invention. In particular, there can be a multiple pack of five pieces indicated by reference C1 , a triple pack indicated by reference C2, a double pack indicated by reference C3, and a single pack indicated by reference C4. Of course, it is also possible to provide other sizes with a different number of products inside and with different pack lengths.

The cut-sew group 22 is preceded by a tunnel forming group 21 , in which the packaging film F is arranged to create a tube T to receive the product P to be packaged within it. Then, the lower portion of the tube T is closed by welding the two free ends F1 and F2 of the packaging film F, which are folded to envelope and surround product P or the products to be packaged.

In the figures, it is possible to see the forming group of the tunnel 21 , in which the packaging film F arrives spread and folded by means of the forming bars 21 a to form the tube T into which the product or products P to be packaged are subsequently inserted. The forming bars 21 a each mount a guide wheel R. At the end of the forming bars 21 a there are two side brushes 21 b and an upper brush 21 c for appropriately shaping the tube T made with the packaging film F.

Once tube T has been created, the lower longitudinal weld is made (relative to the advancement direction of the product or products P to be packaged). Typically, such a longitudinal welding is carried out through a series of pairs of heatsealing wheels RT which heat and form together the lower closure by welding the two free side ends F1 and F2 of the packaging film F (some details are not visible in the drawings).

The tube thus formed, welded in its lower part and filled with the product to be packaged, is then fed to the cut-sew group 22, which allows obtaining the packs by making the transversal welds and the cut to separate two packs from each other. Therefore, every machine M is created with a cut-sew group 22 which mounts a set of tools. In the case illustrated in the figures, the set comprises three tools U1 , U2 and U3 mounted spaced on their respective rotating shafts.

As a function of the various products to be packaged, the cut-sew group 22 presents a different conformation. The packs which can be obtained are of different types and can be long or short, wide or narrow according to the product P that they must contain. The cut-sew group 22 can be used to make the two lateral welds with the size of the required pack length. The packaging film F is welded into a tube wrapper about the product to be packaged, and the cut-sew group 22 is used to separate the mutually different packs. In particular, the rotating cut-sew group 22 defines how long the tube is to be cut and creates welds and cuts at a defined distance. Each cut defines the tail of the pack just finished and the head of the new pack being made. More in detail, the cut is made in the center of the weld, which is performed by a tool of the cut-sew group 22. Figure 9 shows one of the three tools U of the cut-sew group 22 which fits a plurality of spatulas S, in particular the upper tool US is shown. A corresponding lower tool Ul is fitted at the lower shaft (not fully visible). This figure shows the tool U3 to make single packs which mount six spatulas for each of the upper tool US and lower tool Ul.

Figure 9 shows two spatulas S spaced 60 degrees apart. Each spatula S consists of a first welding element S1 and a second welding element S2. The two welding elements S1 and S2 are parallel welding bars, facing each other and spaced to form an opening between them within which the cutting element or blade L is positioned. Typically, the welding bars S1 and S2 have a knurling or grooving SZ on the welding surface which makes the classic crimped impressions on the welds of the packaging film F. The welding bars S1 and S2 of the spatulas S are heated by resistors powered by the current supplied by the collectors.

Figure 9 shows a cutting element L in the form of a serrated blade (or zigzag blade) that allows to make the classic zigzag-shaped cuts for heat-welded flowpack packaging. At the corresponding lower tool Ul, the cutting element is a straight counterblade CL, e.g. as shown in figure 10. The counterblade CL is fitted on cup springs to cushion the blow of the blade L during cutting. The cutting elements L and CL are actuated during or at the end of welding and are controlled by actuators. In particular, the blade L mounted on the upper shaft AS is driven, i.e. it is lowered to approach the counterblade CL fitted on the lower shaft Al and thus make the cut.

The cutting elements L (blade) and CL (counterblade) are preferably made of hard steel.

In particular, the zigzag-shaped cuts can be seen in figure 2 on the side edges of the illustrated packs. A straight cut can also be provided in which both the upper and lower cutting elements are straight and make a scissor-type cut.

In the embodiment shown in the figures, the three tools U1 , U2, and U3 fit three spatulas S, a single spatula S, and six spatulas S, respectively. Therefore, tool U1 fit one spatula every 120 degrees, tool U2 fits a single spatula, and tool U3 fits six spatulas 60° degrees apart.

In this case, preferentially in a non-binding manner, medium packs (two to five products in the same pack) are preferably made with the U1 tool, long packs (seven to ten products in the same pack) are made with the U2 tool, and small packs (single or double) are made with the U3 tool.

On the machine M, there is a centering portion called the machine center CM, i.e. a colored band N indicating the central portion of the machine M. The selection of the tool to be used is made by aligning the tool U1 , U2, or U3 with the machine center CM, that is, by translating transversely the cut-sew group 22 to align one of the three tools with the machine center CM. The machine center position CM is aligned with the feed portion 10 and more in detail with the conveyor belt 12 which feeds the product P.

Once the tool to be used, such as U2, is selected, the upper shaft AS and lower shaft Al are aligned with the Homing operation to match the upper and lower spatulas. Of course, this operation must be repeated whenever the tool is changed. Then a fitting tuning operation is performed between the position of the upper shaft AS and the position of the lower shaft Al. In particular, in the case of tool U3, the lower shaft Al is brought to the home position, then the upper shaft AS is brought to the 30-degree alignment position and stopped. Subsequently, the lower shaft Al is also moved to the 30-degree alignment position to align the spatulas S of the upper tool US and the lower tool Ul.

In the case of the central tool U2, the homing operation brings both shafts to zero and there is a synchronous 360-degree rotation of the two shafts.

Figure 1 1 illustrates a side section of the cut-sew group 22 showing the tools of the cut-sew group 22 and in particular the U3 tool for making single packs which mounts six spatulas S, as mentioned above. The spatulas S are mounted cantilevered from the upper shaft AS and the lower shaft Al. As best seen in figure 11 , the two welding elements S1 and S2 are parallel, facing, and spaced solder bars connected by a central portion S3. The central portion S3 of each spatula S is connected to the shaft AS or Al e.g. by bolted flanges or brackets which are made integral with the shaft on which they are mounted. Spacer elements D can be fitted between the different spatulas S of each tool U.

Figure 14 shows the structure of the cut-sew group 22. In particular, the two upper rotating shafts AS and the lower rotating shafts Al are fitted on a carriage or slide 30 which allows a movement in the direction Y indicated by the arrow. The carriage 30 comprises a support base 31 fitted on two guide rails 34, two uprights 32, and an upper closure portion 33.

The two guide rails 34 extend transversely relative to the product advancement direction X. The support base 31 fits recirculating ball bearing slides 35 (two slides for each rail rod 34) and there is a movement gear driven by a horizontal movement motor MMO.

The upper shaft AS is driven in rotation by an upper motor MS and the lower shaft Al is driven in rotation by a lower motor Ml. The shafts AS and Al are directly engaged on the rotational axes of the respective motor.

The accuracy of the contact between a spatula S of the upper tool US and a spatula of the lower tool Ul is ensured by the motors which move the upper AS and lower Al rotary shafts.

The electrified collectors CS and Cl are mounted on the side opposite to the motors MS and Ml.

With reference to figures 23-26, there is a transmission belt CT in the upper portion of the carriage 30 which turns two pins PE to achieve height adjustment of the upper shaft AS relative to the lower shaft Al. This is a micrometer adjustment which is used to adjust the welding and cutting pressure. It is used to make the spatulas S of the upper and lower tools touch.

The upper shaft AS is held in place by springs MP on which a preload of about 300kg/400kg weighs. This generates an automatic pressure system to hold the upper shaft AS in place. The preload springs MP are used to make the upper shaft AS elastic if something should get stuck between the upper and lower tools.

According to the main technical feature of the invention, therefore, in the horizontal packaging machine M there are means for compensating the mutual distance between the two shafts AS and Al with micrometric adjustment to compensate for thermal expansion and to be able to use packaging films of different thicknesses.

In the upper part of the carriage 30, there is a small electric motor MMV that through a mechanical transmission TM turns a first pulley P1 , which through the belt CT turns a second driven pulley P2 and by virtue of a worm screw moves the upper shaft AS, which carries the upper cut-sew tools US, either up or down. The upper shaft AS is movable micrometrically either up or down, as needed. The upper shaft AS moves parallel relative to the lower shaft Al (so that the two rotation axes remain mutually parallel). The transmission TM is adjusted using operating screws VM.

Therefore, the mutual distance compensation means of the two shafts AS and Al comprise a motor MMV with gearmotor, a pair of gears IN integral with the first pulley P1 , a transmission belt CT tensioned by means of return wheels RR and a second driven pulley P2. The movement is transmitted by two operating screws which tighten and loosen the pins PE attached to the upper shaft AS. In particular, the pins PE are threaded in their upper end portion (with reference to the figures) which is received in threaded bushings within pulleys P1 and P2. The pins PE are mounted between the springs MP.

The upper shaft AS is mounted on two flanges FL slidingly mounted vertically on the uprights 32 of the carriage 30. In particular, the flanges FL are integrally connected to the pins PE and allow the vertical displacement of the upper shaft AS relative to the lower shaft Al by acting on the operating screws VM.

The flanges FL are blocks provided with guide means for sliding, wherein said guide means are, for instance, sliding pads made of brass or low-friction material.

The pitch between two subsequent cut and sew tools is 100mm and the maximum stroke in the case of three cut and sew tools is 200mm. Therefore, as a function of these dimensions, it is possible to increase the footprint of the new cut and sew group 22 inside the machine M itself.

In particular manner, the width of the horizontal packaging machine M remains the same and slightly increases the projection of the cut-sew group from the operator side.

For positioning the correct tool to be used, a motor MMO is present which moves the entire cut-sew group 100 mm to the left or right of its initial position. Therefore it is possible to choose between three different tools with just one displacement of 100 mm in either direction.

Thus, the cut-sew group 22 comprises at least four motors: one for each of the shafts MS and Ml, one for the vertical displacement MMV of the upper shaft AS, and one for the horizontal translation MMO of the cut-sew group 22. In the final machine, there is a safety guard which closes off the entire area of the welding group 20.

To maintain the same overall dimensions compared to the known machines in the new machine, the electrical collectors CS and Cl are moved to the side opposite to the one on which the motors MS and Ml are mounted.

The electrical collectors CS and Cl are longer because they must have diversified control for different tools. The portion of the machine of the invention which houses the electrical collectors CS and Cl is called the casing.

The electrical collectors CS and Cl are connected to an electrical control panel 50 using appropriate wiring.

In the new machine suggested here, the connection cables follow a different path from the known machines and therefore the entire cut-sew group 22 has been modified.

The packaging film F advances and the shafts of the cut-sew group 22 rotate at a speed of 208 revolutions per minute for the tools which mount six spatulas making 1 ,250 packs per minute.

Of course, when the size to be produced changes, so does the speed of rotation of the shafts of the cut-sew group 22.

The rotation speed of the shafts of the cut-sew group 22 varies according to the number of spatulas mounted on the tools in use and the number of packs per minute to be obtained.

The two shafts AS and Al of the cut-sew group 22 rotate synchronously but in opposite directions of rotation.

Once formed, the packs arrive on a conveyor belt which sends them to a packaging machine or are collected in storage boxes.

By virtue of the aforesaid description, it is thus apparent that the horizontal packaging machine and cut-sew group of the present invention achieves the purposes and reaches the advantages mentioned above.

Therefore, the machine according to the present invention provides an automatic tool change of the cut-sew group with a solution which does not require downtime, machines stops, and a skilled operator. Furthermore, the solution suggested here does not particularly modify the total machine footprint, guaranteeing the machine a high degree of flexibility to obtain packs of different sizes with a single packaging machine.

Of course, notwithstanding the principle of the invention, the details of construction and embodiments may vary widely relative to what is described and illustrated purely by way of example, without because of this departing from the scope of the present invention.

Where the constructive features and techniques mentioned in any successive claims are followed by references signs or numerals, such reference signs were introduced for the sole purpose of increasing intelligibility of the claims themselves and consequently, such reference signs have no limiting effect on the interpretation of each element identified by way of example only by such reference signs.