TECHNICAL FIELD

The present invention relates to a labelling machine. The present invention also relates to a labelling method .

BACKGROUND ART

Labelling machines to apply labels on items, in particular containers for pourable food products are known for example from patent application WO2010/040397 in the name of the same Applicant.

These labelling machines substantially comprise:

- an inlet conveyor for feeding items to be labelled;

- an outlet conveyor for feeding items to be labelled; - a conveyor rotating about a first axis and adapted to convey the items from the inlet conveyor to the outlet conveyor; and

- a labelling unit arranged laterally to the rotating conveyor and in a position interposed between the inlet and outlet conveyors.

The rotating conveyor comprises on its periphery a plurality of forming spindles, a plurality of motors to rotate respective forming spindles about respective axes, and a plurality of sealing devices associated to respective forming spindles. The labelling unit comprises feeding means for a band of flat labels, a blade to separate the labels one after another from the band and a drum for transferring the cut labels .

Each forming spindle substantially comprises:

- a main body which is slightly upwardly conical, and provided on top with a support plate for a respective item and a plurality of openings, which can be selectively connected fluidically with a vacuum source; and

- a shaft having a first end engaging, by cam means, a frame of the rotating conveyor and a second end, opposite to the first end, configured like a bell so as to engage a top portion of the item.

The forming spindles are also rotatingly mounted about a second axis, parallel to the first axis, with respect to the periphery of the rotating conveyor.

Each spindle withdraws a respective item to be labelled from the inlet conveyor and moves it along an arc- shaped path, along which it applies a respective flat label cut by the labelling unit on the respective item.

More precisely, when each spindle is at the labelling unit, it is rotated about the second axis in an opposite sense to the drum of the labelling unit. Thereby, a flat cut label is transferred from the drum to the forming spindle and wound on the forming spindle until the opposite edges of the label are overlapped.

The flat label is retained by appropriate openings of the drum connected to a vacuum source. During the step of transferring the label to the spindle, the openings of the drum are connected to a pressurised air source and further openings of the main body of the above said spindle are connected fluidically with the vacuum source.

The label is then retained on the spindle by means of the further openings connected to the vacuum source and the rotation of the forming spindle determines the winding of the label thereon.

At this point, the sealing element seals the opposite edges of the label so as to form a tubular element.

The connection between vacuum source and openings of the forming spindles is then interrupted and the forming spindles are lowered parallelly to the second axis.

Accordingly, each tubular element disengages the main body of the respective forming spindle.

Furthermore, each item is lowered together with the respective forming spindle until it engages the respective tubular element applied thereon.

The rotating conveyor makes each item with the respective tubular element applied thereon available for the outlet conveyor.

The items with the respective tubular elements are then conveyed to a thermal retraction station, in which a heat source determines the retraction of the tubular elements and their ultimate attachment to the respective items .

The above disclosed labelling machines are of the rotating type, i.e. are machine in which the motors, the forming spindles and the sealing devices are rotated by the rotating conveyor about the first axis.

Therefore, the above disclosed labelling machines require a plurality of driving elements, for example slip- rings and/or mechanical joints, to transfer electric and pneumatic power, vacuum and cooling water from respective sources arranged in a fixed position with respect to the rotating conveyor to the loads (for example motors, forming spindles and sealing devices) rotating on this rotating conveyor .

These driving elements make the rotating type labelling machines especially expensive and increase the size thereof and the difficulties in maintenance.

The need is felt in the field for a labelling machine using the above-disclosed "sleeve-drum" technology, which has a reduced overall production cost and/or is easy to maintain, and/or has a reduced size with respect to the solutions of known rotating type labelling machines.

Finally, the need is felt in the field for a labelling machine using the above disclosed "sleeve-drum" technology, the production rate of which can be easily increased without requiring a new design of the labelling machine. DISCLOSURE OF INVENTION

It is an object of the present invention to obtain a labelling machine, which allows to satisfy at least one of the above said needs.

The aforementioned object is achieved by the present invention as it relates to a labelling machine as defined in claim 1.

The present invention also relates to a labelling method according to claim 14.

BRIEF DESCRIPTION OF THE DRAWINGS

A preferred embodiment is hereinafter disclosed for a better understanding of the present invention, by mere way of non-limitative example and with reference to the accompanying drawings, in which:

- figure 1 shows a perspective view of a labelling machine made according to the invention, with parts removed for clarity;

- figure 2 shows a top view of first details of the labelling machine according to figure 1 ;

- figure 3 shows a top view of the labelling machine according to figure 1 ;

- figures 4 and 5 show a side view of further details of the labelling machine of figures 1 to 3 ;

- figure 6 shows a perspective view on an enlarged scale of a first embodiment of a detail of the labelling machine of figures from 1 to 5 ;

- figure 7 shows a perspective view on an enlarged scale of a second embodiment of a detail of the detail of the labelling machine shown in figure 6 ;

- figure 8 shows on an enlarged scale a working step of the labelling machine of figures 1 to 7; and

- figure 9 shows a particularly enlarged view of the details in figure 6.

BEST MODE FOR CARRYING OUT THE INVENTION

With reference to figures from 1 to 3, numeral 1 indicates a labelling machine adapted to apply labels 2 on items 3 , 3 ' .

In particular, items 3, 3' are filled with a pourable food product, yoghurt in the case shown.

Labelling machine 1 is of the "shrink-sleeve" type, i.e. adapted to:

- form tubular elements 4 from corresponding flat labels 2 made of thermally retractable material;

- apply the tubular elements 4 to respective items 3, 3' with a certain circumferential play; and

- determine the thermal retraction of labels 2 applied on respective items 3, 3' so as to attach labels 2 in a final position on respective items 3, 3'.

In greater detail, labelling machine 1 comprises:

- a frame 5 ;

- a conveyor 6 adapted to feed items 3, 3' along a labelling path P;

- an inlet star wheel 10 adapted to feed items 3, 3' to be labelled to conveyor 6; and

- an outlet star wheel 11 adapted to move labelled items 3 from conveyor 6.

More in particular, conveyor 6 comprises a pair of rectilinear and opposite branches 7, 8 and a branch 9 configured as an arc of semicircle and interposed between branches 7 , 8.

Branch 7 is interposed between star wheel 10 and branch 9 and branch 8 is interposed between branch 9 and star wheel 11.

Branches 7, 8 are parallel to respective directions A, A' and are covered by items 3, 3' respectively in a first sense and a second sense which are opposite to each other.

In the case shown, directions A, A' are horizontal.

Path P comprises:

- an inlet station I;

- a rectilinear segment Q, corresponding to branch 7 and covered by items 3, 3' in a first sense;

- a curved segment R corresponding to branch 9; - a rectilinear segment S, corresponding to branch 8 and covered by items 3, 3' in a second sense; and

- an outlet station U.

Segments Q, S extend parallelly to respective directions A, A'.

Conveyor 6 is in the case shown of the chain type.

Conveyor 6 comprises a flat surface, from which a plurality of engaging elements 12 for respective items 3, 3 ' protrudes .

Engaging elements 12 moving along branches 7, 8 are symmetrical with respect to corresponding axes aligned along respective directions A, A'.

Star wheel 11 defines a thermal retraction station of labelling machine 1. This thermal retraction station is not disclosed herein in detail, as it is not part of the present invention.

Labelling machine 1 also includes:

- a labelling unit 15 (figure 3); and

- a pair of carriages 16, 17 arranged on opposite sides of labelling unit 15.

Carriages 16, 17 extend parallelly to respective directions G, G' parallel to directions A, A', and slide with respect to frame 5 along respective directions G, G' and along respective directions C, C'.

In particular, carriages 16, 17 are moved parallelly to respective directions G, G' by respective motors 55 and parallelly to respective directions C, C' by respective motors 56. In particular, motors 55, 56 are of the brushless type (Figure 2) .

Directions C, C' are orthogonal to directions G, G' and extend horizontally in the case shown.

Each carriage 16, 17 comprises a frame 30 and a plurality of modules 20, 21 attached to frame 30.

Frame 30 of each carriage 16, 17 comprises (Figure 1, 4 and 5) :

- a bar 31 extending parallelly to corresponding direction G, G';

- a plate 32 lying on a plane defined by respective directions A, A' and C, C', and arranged horizontally in use;

- a plate 34 parallel to and spaced from plate 32;

- a pair of plates 33 interposed between plates 32, 34, parallel to one another and lying on respective planes orthogonal to directions C, C'; and

- a plurality of plates 35 protruding integrally and downwards from plate 34 and parallel to plates 33.

Plates 35 are alternated along corresponding direction G, G' to vertically open hemicylindrical seats 36.

Plates 33 are trapezoidal and lie, in the case shown, on respective vertical planes. With reference to figure 4, each module 20, 21 is formed by:

- a forming spindle 22, 23 extending along a respective axis D, D' and adapted to withdraw a respective label 2 from labelling unit 15;

- an engine 24, 25 adapted to rotate a respective spindle 22, 23 about corresponding axis D, D', so as to determine the coaxial winding of label 2 on respective spindle 22, 23;

- a sealing element 26, 27 adapted to weld opposite edges 48, 49 of label 2 and form a corresponding tubular element 4; and

- a transfer element 28, 29 adapted to transfer tubular element 4 on a corresponding item 3, 3'.

Labelling unit 15 comprises a roller rotating about a vertical axis to feed a continuous band of labels 2, a cutting element (not shown) to separate single labels 2 from the band, and a drum 14 rotating about a vertical axis F in a clockwise direction with reference to the position shown in Figure 3.

Drum 14 receives labels 2 separate from one another from roller, retains them by the action of vacuum and makes them available to spindles 22, 23 of carriages 16, 17.

In particular, the outer side surface of drum 14 comprises a plurality of openings which are connectable selectively to a vacuum source to transfer labels 2 to spindles 22, 23 of carriages 16, 17.

The side surface of drum 14 is tangent to a plane V parallel to directions A, A' on the side of branch 7 and thus to direction A.

The side surface of drum 14 is tangent to a plane V parallel to directions A, A' on the side of branch 8 and thus to direction A'.

Planes V, V are arranged on diametrically opposite sides of axis F of drum 14.

Each motor 24, 25 is arranged on one (top) side of corresponding plate 34 while each spindle 22, 23 is arranged on the other (bottom) side of corresponding plate 34.

Each spindle 22, 23 comprises on its external side surface a plurality of openings 18 connectable to a vacuum source .

The side surfaces of spindles 22 (23) are tangent on the side of drum 14 to a same plane N (Ν') parallel to plane V (V) (Figure 2).

The axes of spindles 22 (23) define a plane M (Μ') parallel to plane V (V) .

Drum 14 is arranged on the side opposite to plane N (Ν') with respect to plane M' (Μ').

Planes M, M', N, N' are arranged vertically in the case shown.

Spindles 22, 23 further comprise respective rollers 37 adapted to ease the sliding and adhesion of corresponding labels 2 transferred from drum 14.

When each label 2 is transferred from drum 14 to corresponding spindle 22, 23, the connection between the openings of drum 14 and the first vacuum source is interrupted and the openings and the second vacuum source of spindle 22, 23 are simultaneously connected.

Sealing element 26, 27 of each module 20, 21 is borne by corresponding plate 35 and is arranged in a position interposed between relative plate 35 and relative spindle 22, 23.

Each sealing element 26, 27 is mobile along relative direction C, C with respect to relative plate 35 from and towards relative spindle 22, 23, to weld edges 48, 49 of relative label 2 and form corresponding tubular element 4.

In particular, sealing element 26, 27 is of the welding bar type.

Each transfer element 28, 29 comprises essentially

(figures 4 and 5) :

- an actuator 40 comprising a fixed part 38 and a stem 39 extending parallelly to relative axis D, D' which can slide with respect to frame 30 of relative carriage 16, 17 forwards and backwards parallelly to axis D, D' and passing with play through plate 34 of corresponding carriage 16, 17; and

- a gripping element 41 arranged at an end 42 of actuator 40 and sliding on guides 70 parallel to axis D, D' .

More in particular, each transfer element 28, 29 comprises :

- an element 71 configured as a C and sliding on guides 70; and

- a plate 72 interposed between gripping element 41 and element 71.

Each gripping element 41 is configured as a half- cylinder having axis D, D', and comprises on its wall 43 facing corresponding tubular element 4, 4', a plurality of openings 44 selectively connectable with a third vacuum source 80 (only diagrammatically shown in Figure 9) .

Each wall 43 cooperates, in greater detail, with a side surface 60 of tubular element 4 which is external to relative axis D, D' .

Wall 43 of each transfer element 28, 29 is also integrally mobile with relative tubular element 4 between the respective lowered and lifted positions. In other words, there are no parts of gripping element 41 which are mobile in relation to tubular element 4, when the relative transfer element 28, 29 moves from the lifted position to the lowered position.

Each gripping element 41 is normally arranged in an intermediate position along relative axis D, D' between a lifted position (shown in Figure 4) in which it withdraws respective tubular element 4 from relative spindle 22, 23 and a lowered position (shown in figure 5) in which it applies respective tubular element 4 on corresponding item 3, 3 ' .

When each gripping element 41 is in the lifted position, the connection between openings 18 and the second vacuum source is interrupted while openings 44 are connected with third vacuum source 80. Thereby, each gripping element 41 withdraws respective tubular element 4 from relative spindle 22.

When each gripping element 41 is in a lowered position, the connection between openings 44 and third vacuum source 80 is interrupted. Thereby, each gripping element 41 can apply relative tubular element 4 on corresponding item 3, 3'.

As an alternative, gripping elements 41 of each carriage 16, 17 could be connected to one another by a crossbar 50 extending parallelly to relative direction G, G' (Figure 7) .

Advantageously, each carriage 16, 17 is alternatively mobile according to a cycle comprising: - a respective forward run along which respective spindles 22, 23 receive respective labels 2 from drum 14 of respective labelling unit 15; and

- a respective return run along which respective tubular elements 4 are made available to corresponding items 3, 3' moving forward on corresponding branches 7, 8 of conveyor 6.

In greater detail, carriages 16, 17 cover the respective forward runs following senses opposite to the senses by which items 3 move on corresponding branches 7, 8.

Carriages 16, 17 also cover the respective return runs following the same senses as the senses by which items 3 move on corresponding branches 7, 8.

In other words, carriage 16 covers the forward run in the second sense and the return run in the first sense. Carriage 17 covers the forward run in the first sense and the return run in the second sense.

Each carriage 16, 17 is arranged, during the respective forward run, in a first position in which the relative direction G, G' coincides with a direction B, B' tangent to the side surface of relative spindles 22, 23 on the side of drum 14 and to the side surface of drum 14 on the side of direction A, A' .

In other words, during the forward runs of respective carriages 16, 17, the planes N, N' defined by relative spindles 22, 23 coincide with respective planes V, V and directions B, B' lie on such respective coinciding planes N, V; N ' , V.

Each carriage 16, 17 is arranged during the respective return run, in a second position in which directions A, A' coincide with planes M, M' defined by relative spindles 22, 23 (Figures 2 and 3) .

In other words, the symmetry axes of spindles 22, 23 lie on the same plane as the symmetry axes of engagement elements 12.

The forward runs of carriages 16, 17 are covered at a constant speed.

In particular, during the forward runs of carriages 16, 17, labels 2 are transferred from drum 14 and wound on corresponding spindles 22, 23.

During the return run, transfer elements 28, 29 transfer corresponding tubular elements 4 on relative items 3, 3' moving forward on branches 7, 8.

The working cycle of each carriage 16, 17 also comprises :

- a first inversion run covered at the end of the forward run and before the return run; and

- a second inversion run covered at the end of the return run and before the forward run. The first and the second inversion runs are covered by carriages 16, 17 in respective planes defined by directions A. C A. C ·

Motors 55, 56 are simultaneously actuated during the first and the second inversion runs.

These planes are horizontal in the case shown.

During the first inversion run, each carriage 16 (17) :

- decelerates from the constant speed by which it covers the forward run in the second (first) sense until it reaches a forward speed equal to zero along direction B, B' ;

- moves away from drum 14 in the direction of relative branch 7 (8) until it reaches the relative second position; and

- accelerates along direction A (Α') in the first

(second) sense until it reaches the constant speed by which it moves along the relative return run.

During the second inversion run, each carriage 16

(17) :

- decelerates from the constant speed by which it covers the return run in the first (second) sense until it reaches a forward speed equal to zero along direction A (A' ) ;

- approaches drum 14 moving away from relative branch 7 (8) until it reaches the relative second position; and - accelerates along direction B (Β') in the second (first) sense until it reaches the constant speed by which it moves along the relative return run.

Sealing devices 26, 27 weld opposite edges 48, 49 of relative labels 2 and form corresponding tubular elements 4 during the first inversion run of relative carriage 16 (17) .

It should be highlighted that the working cycles of carriages 16, 17 are offset in the course of time with respect to one another by a time interval equivalent to half of the working cycle of carriage 16, 17 plus a further time interval required to ensure that labels 2 present on drum 14 are moved from plane V to plane V.

In the case shown, drum 14 approaches three labels 2 at a time. Therefore, the further time interval is equal to the time required to move one label 2 and a half forward on drum 14.

In particular, while carriage 16 (17) covers the whole relative forward run, carriage 17 (16) completes the relative forward run, covers the relative first inversion run, the relative return run and starts the relative second inversion run.

While carriage 16 (17) covers the relative first inversion run, carriage 17 (16) completes the relative second inversion run. While carriage 16 (17) covers the relative return run and the relative second inversion run, carriage 17 (16) starts the relative forward run.

The duration of the forward run of each carriage 16 (17) is equal to half of the whole working cycle.

Transfer elements 28 transfer tubular elements 4 on items 3 which move forward on branch 7 while carriage 16 covers the return run.

Transfer elements 28 do not transfer tubular elements 4 on items 3' which move forward on branch 7 while carriage 16 covers the forward run.

Accordingly, branch 9 of conveyor 6 transfers along segment S items 3, on which tubular element 4 has been applied, and items 3' which still do not have tubular element 4 applied.

Transfer elements 29 transfer tubular elements 4 on items 3' which move forward on branch 8 while carriage 17 covers the return run.

Transfer elements 29 do not transfer tubular elements 4 on items 3 - on which relative tubular elements 4 have been previously applied - which are on branch 8 while carriage 16 covers the forward run.

In use, star wheel 10 feeds items 3, 3' to conveyor 6.

Hereinafter, all items 3, 3' move forward on branches 7, 9, 8 of conveyor 6 covering sequentially segments Q, R, S of path P.

More in particular, transfer elements 28 apply respective first tubular elements 4 on corresponding items 3 while the latter move along branch 7 of conveyor 6.

Transfer elements 28 of carriage 16 do not apply first tubular elements 4 on items 3' while the latter move forward along branch 7 of conveyor 6.

Therefore, branch 9 of conveyor 6 is covered by items 3 on which respective first tubular elements 4 are applied and by items 3' on which second tubular elements 4 must still be applied.

Transfer elements 29 of carriage 17 transfer respective second tubular elements 4 on corresponding items 3' while the latter move forward along branch 8 of conveyor 6.

Items 3 do not receive any tubular element 4 while they move forward on branch 8.

Therefore, star wheel 11 moves items 3 on which first tubular element 4 has been applied along branch 7 of conveyor 6 and items 3' on which second tubular element 4 has been applied along branch 8 of conveyor 6.

First and second tubular elements 4 are subjected to a thermal retraction operation while they move forward on star wheel 11. Thereby, first and second tubular elements 4 are fixed respectively to items 3, 3'. More precisely, each carriage 16 (17) performs a working cycle comprising:

- a respective forward run, in which carriage 16 (17) is arranged in the first position and drum 14 transfers a plurality of first labels 2 to respective spindles 22 (23);

- a first inversion run, in which each carriage 16 (17) moves in the plane defined by directions A, C (Α', C) from the first to the second position and moves away from drum 14 towards branch 7 (8) of conveyor 6 ;

- a respective return run, in which carriage 16 (17) is arranged in the second position, and transfer elements 28 (29) transfer corresponding tubular elements 4 to corresponding items 3 (3') moving forward on branch 7 ( 8 ) ; and

- a second inversion run, in which each carriage 16

(17) moves in the above said plane defined by directions A, C (Α', C) from the second to the first position and moves forward from branch 7 (8) of conveyor 6 to drum 14.

Carriages 16, 17 cover the above said forward and return runs with respective constant speeds.

The working cycles of carriages 16, 17 are offset with respect to one another.

In particular, while carriage 16 (17) covers the whole relative forward run, carriage 17 (16) completes the relative forward run, covers the relative first inversion run, the relative return run and part of the relative second inversion run.

While carriage 16 (17) covers the relative first inversion run from drum 14, carriage 17 (16) completes the relative second inversion run and covers most of the relative return run.

The duration of the forward run of each carriage 16 (17) is equivalent to the sum of the durations of the first and second inversion runs and of the return run, and is equivalent to half the working cycle of carriage 16, 17.

The working cycle of each carriage 16 (17) is disclosed in greater detail hereinafter, from a condition in which carriage 16 (17) is in the respective first position and at the beginning of the respective forward run, and in which transfer elements 28 (29) are in the respective intermediate positions.

More precisely, planes N, V and (Ν', V) coincide in this condition.

The band of flat labels 2 is unwound from the roller of labelling unit 15 and the cutting element separates single labels 2 from the band.

The openings of drum 14 are connected to the first vacuum source, so that separated labels 2 are rotated one after another by drum 14 about axis F.

Carriage 16 (17) covers the forward run parallelly to direction B (Β') in the second (first) sense and, thus, in a sense opposite to items 3, 3' moving forward along segment Q (S) of path P.

During the forward run of carriage 16 (17), spindles 22 (23) reach one after another the generating line of side surface of drum 14 lying on plane V (V) .

First (second) labels 2 are transferred, on after another, from drum 14 to relative spindles 22 (23), during the forward run of carriage 16 (17) .

More precisely, when first (second) labels 2 reach plane V (V), the openings of drum 14 adjacent at this moment in time to plane V (V) are disconnected from the first vacuum source and openings 18 of spindles 22 (23) adjacent at this moment in time to drum 14 are connected to the second vacuum source. Thereby, first (second) labels 2 are transferred from drum 14 to spindles 22 (23) .

In the following portion of the relative forward runs, motors 24 (25) determine the rotation of spindles 22 (23) about corresponding axes D (D'), so as to determine the winding of first labels 2 on spindles 22 (23) .

The rotation of spindles 22 (23) occurs in a direction opposite to the rotation of drum 14. Rollers 37 also ease the winding of first (second) labels 2 on spindles 22 (23) .

At the end of the respective forward run of carriage 16 (17), first (second) labels 2 are completely wound on spindles 22 (23) so that edges 48, 49 are overlapped to one another .

At this point, carriage 16 (17) covers the respective first inversion run, in which drum 14 moves away from branch 7 ( 8 ) .

More precisely, during the first inversion run, each carriage 16 (17) :

- decelerates from the constant speed by which it covers the forward run in the second (first) sense until it reaches a forward speed equal to zero along direction B, B' ;

- moves away from drum 14 in the direction of relative branch 7 (8) until it reaches the relative second position; and

- accelerates along direction A (Α') in the first

(second) sense until it reaches the constant speed by which it moves along the relative return run.

During the first inversion runs of carriage 16 (17), sealing elements 26 (27) are actuated. Thereby, sealing elements 26 (27) weld to one another edges 48, 49 of first labels 2 wound on spindles 22 (23) and form first tubular elements 4.

After the first inversion run is completed, carriage 16 (17) covers the respective return run in a direction parallel to direction A (Α') . In particular, carriage 16 (17) covers the return run in the first (second) sense.

Thereby, carriage 16 (17) covers the respective return run in the same sense as the sense by which items 3, 3' move forward on branch 7 (8) .

During the respective return run, carriage 16 (17) moves with the same speed as corresponding branch 7 (8) of conveyor 6.

In this homocinetic condition, transfer elements 28 (29) transfer first tubular elements 4 on corresponding items 3 ( 3 ' ) .

More in particular, actuators 40 move transfer elements 28 (29) from respective intermediate positions towards the respective lifted positions.

At this point, openings 44 of gripping elements 41 are connected with third vacuum source 80 and openings 18 are disconnected from third vacuum source 80.

There follows that first (second) tubular elements 4 are transferred from spindle 22 (23) to transfer element 28 (29).

Once transfer is completed, actuators 40 move respective gripping elements 41 of transfer elements 28 (29) from the respective lifted positions to the respective lowered positions, at which items 3 (3') are.

At this point, the connection between openings 44 of gripping elements 41 and third vacuum source 80 is interrupted .

There follows that gripping elements 41 of transfer elements 28 (29) release respective tubular elements 4 on items 3 (3') moving forward on branch 7 (8) of conveyor 6.

It should be noted that each item 3, 3' entirely covers labelling path P and is therefore moved forward along branches 7, 9 and 8 of conveyor 6.

However, items 3 are reached by carriage 16 during the return run of carriage 16 and thus receive relative first tubular elements 4 from gripping elements 41 of corresponding transfer elements 28.

Items 3' are not reached instead by carriage 16 during the relative return run. Therefore, items 3' reach branch 9 of conveyor 6 without respective tubular elements 4.

When items 3' reach branch 8, they are reached by carriage 17 during the return run of carriage 17 and thus receive relative second tubular elements 4 from gripping elements 41 of corresponding transfer elements 29.

Items 3 - on which transfer elements 28 have applied respective first tubular elements 4 along branch 7 - are instead not reached by carriage 17 during the relative return run. Therefore, further second tubular elements 4 are prevented from being applied on items 3.

At the end of the respective return runs, carriages 16, 17 cover the respective second inversion runs along which they approach drum 14.

More precisely, during the second inversion run, each carriage 16 (17) :

- decelerates from the constant speed by which it covers the return run in the first (second) sense until it reaches a forward speed equal to zero along direction A (A' ) ;

- approaches drum 14 moving away from relative branch 7 (8) until it reaches the relative second position; and

- accelerates along direction B (Β') in the second (first) sense until it reaches the constant speed by which it moves along the relative return run.

At this point, the working cycle of carriages 16, 17 starts again.

From an analysis of the features of labelling machine 1 and of the relative labelling method according to the present invention, the advantages it allows to obtain are apparent .

In particular, spindles 22, 23 and sealing elements

26, 27 move alternatively along respective forward and return runs, during the formation of tubular elements 4 and their following application on items 3, 3'.

Therefore, labelling machine 1 does not need driving elements required to make electric power, pneumatic power, vacuum and cooling water available from fixed sources to rotating members.

Accordingly, labelling machine 1 results simpler to build, easier to maintain and smaller with respect to the rotating labelling machine disclosed in the introduction of the present description.

Carriages 16, 17 are synchronised with one another so that one of carriages 16, 17 covers the relative return run while the other of carriages 16, 17 covers the relative forward run.

Therefore, the working cycle of carriages 16, 17 ensures that all items 3, 3' receive corresponding tubular element 4.

Transfer elements 28, 29 transfer respective tubular elements 4 from relative spindles 22, 23 to corresponding items 3, 3', by the action of vacuum.

Accordingly, transfer elements 28, 29 allow to transfer relative tubular elements 4 without generating risks of folding and/or crimping of tubular elements 4.

Furthermore, transfer elements 28, 29 allow to apply relative tubular elements 4 at an adjustable height on corresponding item 3, 3', therefore increasing the flexibility of labelling machine 1.

Finally, the productivity of labelling machine 1 can easily be increased, increasing the number of modules 20, 21 present on each carriage 16, 17.

It is finally apparent that changes and variants can be made to the labelling machine 1 and to the labelling method described and shown herein without departing from the scope of protection of the present invention.

In particular, the labelling machine could comprise only one carriage 16 or 17.