The present invention relates to a machine for producing stacks of tags starting from at least one sheet in which said tags are printed in regular manner on one or both its surfaces.

Currently, a sheet (or a length of web) is transformed into a stack of tags by several separate independent machines, each of which carries out a single specific operation. In particular, card cutters, rotary bitted drills, column stackers, rotary and cylindrical plane punches are usually used.

The main drawbacks related to the use of these are control difficulty, operating slowness, the large number of operators (generally at least one for each machine) and low precision. In greater detail, the card cutter makes its cut on packs consisting of a plurality of sheets, consequently the result obtained is not particularly accurate; column stackers, during intercalation, are subjected to constraints linked to the number of cards to be stacked and their format. Finally, the fact that, to define the final shape and dimensions of the tags, the punch cutting tools require dies which have to be purposely created for each specific tag type; moreover the punch cutting tools usually make the cut without separating the cut part.

Again, said traditional machines involve highly repetitive operations, causing stress and lack of attention for the operators, which means that the machines are not always safe.

Moreover, if the tags have to be stacked in accordance with variable codes (consisting for example of progressive or imaginary numbers) printed on the starting sheet, the complexity and slowness of the operations increase. The drawbacks increase substantially if the overall number of tags to be handled is high and variable, obliging the operators to carry out counting, checking and laborious operations.

US 4405121 describes a machine for producing stacks of card pieces from a sheet on which said pieces are printed in ordered m anner. Th is machine com prises a sheet feed and advancem ent station, a station for longitudinally cutting the sheet and a station for transversely cutting the sheet, and a stacking station. In particular, the longitudinal cutting station divides the sheet into strips, but leaving non-usable portions at the ends. The sheet advancement station uses rollers positioned such as to be in contact with a part of the sheet at the m om ent i n wh ich th is enters the su bseq uent longitudinal cutting station.

The object of the present invention is to propose a machine producing one or more stacks of tags with elim ination of the drawbacks of traditional machines, and with high productivity.

Another object of the invention is to provide a m ach ine which is com pletely automatic and safe and requires at most a single operator with essentially supervisory functions.

Another object of the invention is to provide a machine in which the tags can be stacked in predefined order on the entering sheet.

Another object of the invention is to provide a machine in which the final tag dimensions can be varied easily and quickly.

Another object of the invention is to provide a mach ine of lim ited production cost and which is easy and comfortable to use. All these objects and others which will be apparent from the ensuing description are attained, according to the invention, by a machine suitable for producing stacks of tags, having the characteristics indicated in claim 1 .

The present invention is further clarified hereinafter by way of a preferred em bodiment, with reference to the accom panying drawings, in which:

Figure 1 is a block scheme showing the entry elements and exit elements for a machine according to the invention,

Figure 2 is a plan view of the machine according to the invention,

Figure 3 is a view thereof on the line Ill-I ll of Figure 2, and

Figure 4 is a block scheme showing certain steps carried out by the machine according to the invention.

As can be seen from the figures, the machine 2 according to the invention receives at its inlet at least one sheet 4, on which the tags 6 are regularly printed, and provides at its outlet one or more stacks 8 of said tags 6.

In particu lar, the entering sheet 4 is of rectangu lar shape and is preferably of paper, but could also be a printable support in plastic material, for example PVC. In greater detail, the tags 6 printed on the sheet 4 (on one or both sides) are of equal dimensions and are disposed in ordered manner to form rows and columns.

The machine 2 according to the invention comprises a feed station 1 0 for the sheets 4. Preferably, one or more packs of sheets 4 are positioned in the feed station 1 0 in a "stepped" arrangement, i.e. such that the individual sheets 4 of the pack or packs are superimposed with a slight longitudinal sl i ppage (see F igures 2 and 3) . I n greater detai l , the sheets 4 can be positioned on the feed station 10 manually by the operator or, advantageously, by robotized means suitably arranged for positioning the packs of sheets 4 and/or for their "stepping".

Means, not shown, can also be conveniently provided at the inlet to the feed station 10 to receive said sheets 4 from a roll. For example, these means comprise blades disposed such as to cut the web unwinding from said roll into pieces.

In greater detai l , the feed station 1 0 com prises an advancement surface in the form of belts 1 2 on which the sheets 4 are positioned. In particular, the belts of the surface 12 are controlled such as to advance in constant steps corresponding to the stepping of the sheets 4.

Conveniently, the advancement pitch of the belts of the surface 12 is set by a control unit 16 (for example a PLC) for the entire machine.

Preferably, the advancement surface 12 is bounded on one side by a longitudinal edge 1 8 against which the sheets 4 rest, while on the opposite side, a striker wall, not shown, is provided which ensures correct longitudinal consolidation of the sheets 4.

Downstream of the feed station 1 0 an individual izing station 20 is provided, i.e. a station in which the upper sheet 4 of the pack is separated, i.e. "individualized" with respect of the other sheets of the pack, to facilitate its subsequent withdrawal. In particular, in the individualizing station 20, rollers 22 are provided which vertically press the advancing pack of sheets 4, at said rollers a toothed wheel 24 is provided, the individual teeth of which are made to engage the rear edge of the individual sheets to vertical ly space them apart. The purpose of this spacing is to facilitate the lateral entrance of puffs of air between the sheets to separate each sheet from the adjacent sheets. In greater detail, these puffs of air are generated by lateral nozzles, not shown, of adjustable position.

Downstream of the individualizing station 20 a withdrawal station 28 is provided. In greater detail, this latter comprises a suction unit 30, provided for example with suckers and movable longitudinally along lateral guides 31 .

Downstream of the withdrawal station 28 an advancement station 32 is provided. This comprises two belts 34, 36, advancing at the same speed, at least one of which is perforated and is connected to a vacuum source, not shown. Conveniently, the suction function for the perforated belt or belts 34, 36 is set on the basis of the quality, weight and thickness of the sheet 4 being worked, with suitable adjustment of the vacuum source connected to it. The presence of the perforated suction belt or belts 34, 36 ensures precision of sheet positioning during the subsequent cutting steps.

The advancement station comprises at its inlet a first contact stop 37, and in its central region a second stop 38. In greater detail, at the second stop 38 trad itiona l opt ica l sensors , not shown , are i nsta l led to read identification images (for example numeric or bar codes) printed on the sheet 4.

Downstream of the advancement station 32 a longitudinal cutting station 40 is provided, in which the sheet 4 is subjected to longitudinal cutting which divides it into a plurality of strips 41 of width 43 corresponding to the width of the tags 6 to be obtained (see Figure 4). In particular, the longitudinal cutting station 40 com prises a plurality of equidistant paral lel rotating knives 42.

Preferably, the cutting station 40 comprises two synchronous pairs of rol lers 46, 48 positioned respectively upstream and downstream of the rotating knives 42. In greater detail, each pair of rollers 46, 48 consists of an upper roller and a lower roller which are disposed such as to firm ly retain the sheet passing between them and prevent any movements during the cutting step.

Conveniently, downstream of the longitudinal cutting stati on 40 a perforation station 50 can be provided, comprising perforators 52 preferably disposed along a transverse bar, and arranged to make one or more holes in each tag, in accordance with the programme set in the control unit 16.

Downstream of the longitudinal cutting station 40, and of the possible perforation station 50, a transverse cutting station 54 is provided. Th is comprises a vertically movable cutter 56 which transversely cuts the strips 41 of the sheet 4 to form a plural ity of rows 57 of tags 6. In particular, each action of the transverse cutter 56 is controlled such as to obtain rows 57 of tags 6 of length 59 corresponding to the length of the tags 6 to be obtained.

Downstream of the transverse cutti ng station 54 a station 58 is provided for transferring each row 57 of tags 6 to the subsequent stacking station 60. This transfer station 58 comprises first belts 62, which transfer one row 57 of tags 6 at a time to a transverse perforated suction belt 64 connected for this purpose to a vacuum source. Preferably the number of first transfer belts 62 corresponds to the number of strips 41 into which the sheet 4 has been divided in the longitudinal cutting station 40. Advantageo us ly, the tran sve rse perfo rated sucti on be lt 64 is connected to a belt 66 made of a high friction material (for example rubber) in order to further separate the individual tags of each row 57 from each other.

Downstream of the transfer station 58 the stacking station 60 is provided, comprising a cyclic phase stacker 68 into which the tags of each individual row 57 are discharged one on the other such as to hence obtain a stack 8 of tags. This stacker 68 has movable bottom vanes such that, when a certain number of tags 6 has been reached, the vanes are opened to cause the hence formed stacks to fall onto a subsequent stack division station 70.

This stack division station 70 is positioned at a lower level than the stacking station 60 and com prises a rotating carousel 72 provided with compartments 74, each of which is able to receive a predetermined number of stacked tags 6. Suitable sensors are provided at the stacker 68 and/or the station 70 to measure the number of tags.

As already stated, the machine 2 com prises a control unit 1 6 which com mands, controls and coordinates the operations carried out in all said stations.

The operation of the machine 2 according to the invention clearly derives from the aforegoing description.

Initially, a pack of sheets 4 is positioned on the advancement surface 1 2 of the feed stati o n 1 0 s uch that the sheets 4, preferably mutually "stepped", arrives in proximity to the individualizing station 20. Here, the rollers 22 vertically press the advancing pack of sheets 4, while the toothed wheel 24 engages with its individual teeth the rear edge of the individual sheets to an extent sufficient to facilitate lateral entry of air puffs between them to hence separate each sheet from the adjacent sheets.

The suction unit 30 of the withdrawal station 28 grips the individual sheet 4 and, during its translation along the guide 31 , retains this sheet until it brings it to the advancement station 32. In particular, the gripped sheet 4 is released onto the advancement station 32 such that its rear edge contacts the first stop 37, which defines the zero reference for this station.

The front edge of the sheet 4 moved by the advancement station 32 is then blocked by the second stop 38, at which any identification codes printed on the sheet 4 are suitably read.

When the control unit 16, in synchronism with the other operations, releases the sheet 4 from the second stop 38, it is able to advance towards the longitudinal cutting station 40 where, as a result of passage through the blades of the rotati ng kn ifes 42 , it is d ivided into stri ps 41 of width 43 corresponding to the width of the tags 6 to be obtained. During the longitudinal cutting, the sheet 4 is suitably retained by both the pairs of rollers 46 and 48 positioned respectively upstream and downstream of the rotating knives 42.

After possible perforation by the perforators 52 of the station 50, the longitudinal strips 41 of the sheet 4 enter the transverse cutting station 54 where they are cut transversely such as to obtain, in sequence, a series of rows 57, each of which consists of tags 6', 6", 6"'.

In sequence, each row 57 of tags is then transferred by the belts 62, 64 and 66 of the transfer station 58 to the stacking station 60. On reaching in proximity to this, the tags 6', 6", 6"' of each row 57 are discharged, one after another, into the stacker 68 to hence form the stack 8 of tags 6, as a result of their superimposing.

The stacks 8 formed within the stacker 68 preferably consist of only a small number of tags 6, to prevent these from being able to be im peded by other tags, due for example to inevitable burrs due to the cutting.

Then when the stack 8 of tags has reached the required number inside the stacker 68 (m easured by a suitable sensor) , the lower vanes of the stacker open to cause the stacked tags to fall into one of the compartments 74 of the underlying rotating carousel 72. In particular, each compartment 74 of the carousel 72 is filled with a sequence of stacks 8 formed in the stacker 68 until a stack of tags 6 of the desired number is obtained. In this manner, once this number has been reached, the carousel 72 is made to advance through one step to enable the next compartment 74 to be filled.

Advantageously, the width 43 of the strips 41 , and hence of the tags 6 to be stacked, can be varied by sim ply adjusting the distance between the rotating knives 42 of the longitudinal cutting station 40, while the length 59 of the tags 6 to be stacked can be varied by su itab ly setti ng the rate of intervention of the transverse cutter 56 of the station 54.

Moreover, the distance between the upper rollers and lower rollers of the pairs of rollers 46, 48 of the cutting station 40 can be suitably adjusted on the basis of the thickness of the sheet 4 being worked.

Preferably, the stacks 8 of tags 6 formed inside each compartment 74 of the carousel 72 are arranged on the basis of a determ ined sequence 80 defined/printed on the starting sheet 4 (see Figure 1 ). Essentially, on the basis of the reading by the optical sensor, the control un it 1 6 is able to command, control and suitably vary the division of the stacks 8 between the various compartments 74 of the carousel 72, such as to obtain stacks 8 of tags divided in accordance with the required criteria and hence ready for subsequence use.

Advantageously, a specific verification test is im plemented in the interior of the control unit 1 6 or in the interior of a different control unit 84 suitably arranged for this purpose; in particular, a check is made on whether the num ber of tags 6 obtained from each sheet 4, and/or in the stacks 8 of tags 6, as counted at the stacker 68 and/or at the com partments 74, are consistent with that measured by the optical sensor on the starting sheet 4; if this is not the case (for example, if the number of tags obtained is less than that read by the sensor on the starting sheet) , the control u n it 1 6 or 84 activates means, not shown, which feed a preferably acoustic or light warning signal to the operator.

From the aforegoing it is apparent that the machine according to the invention is particularly advantageous in that:

- it is of particularly high productivity, on average about 33000 tags per hour, and in any event substantially within the range of 25000 - 50000 tags/hour,

- it enables high precision to be achieved, given that it cuts one sheet at a time,

- it is completely automatic and at most requires a single supervisor,

- it does not use any hollow punches,

- it enables high personalization to be achieved, both in the shape and dimensions of the tags to be stacked, - it enables stacks to be formed with the required number of tags, which can be set by the operator, and/or be established automatically on the basis of the readings carried out by the optical sensor,

- it enables stacks of tags to be obtained which are arranged and/or divided in accordance with a defined sequence printed on the starting sheet.