Cutting unit for labelling material provided with an Anti-collision element

Abstract

There is described a cutting unit (11) configured to cut a web (4) of labelling material, the cutting unit (11) comprises: a first cutting member (14), which carries a cutting group (15) including a blade element (15a) and an anti-collision element (15b); and a second cutting member (12), which includes a first slot (16a), an abutment wall (17) and a second slot (16b) obtained on the abutment wall (17); the first cutting member (14) is configured to cyclically cooperate with the second cutting member (12) so that, during a nominal operative condition of the cutting unit (11), the blade element (15a) repeatedly engages the first slot (16a) for cutting the web (4) and the anti-collision element (15b) repeatedly and contactlessly engages the second slot (16b) during the cutting of the web (4); the cutting unit (11) is configured so that, during a non-nominal operative condition of the cutting unit (11), the anti-collision element (15b) interacts in contact with said abutment wall (17).

Description

[0001] CUTTING UNIT FOR LABELLING MATERIAL PROVIDED WITH AN ANTI-

[0002] COLLISION ELEMENT

[0003] TECHNICAL FIELD

[0004] The present invention relates to a cutting unit for cutting a web of labelling material for labelling articles adapted to contain a pourable product , preferably a pourable food product .

[0005] BACKGROUND ART

[0006] Labelling machines are known, which are commonly used to prepare , transport and apply labels onto articles , such as bottles , flacons or containers of this sort , destined to be filled with a pourable product , in particular a pourable food product .

[0007] Particularly widespread is the use of glued labels , i . e . portions of a labelling material that are cut at appropriate lengths from a web of labelling material , initially wound in form of continuous strip around a reel , and then sprinkled with glue before their appl ication onto the articles .

[0008] In detail , the web of labelling material is progressively unwound of f the relative reel and then repeatedly cut to obtain successive labels of equal length to be glued and applied onto respective articles .

[0009] A typical labelling machine comprises : a carousel rotatable around a vertical axis and configured to convey a plurality of articles along an hori zontal , arc-shaped labelling path; and a labelling module , peripherally arranged relatively to the carousel and configured to prepare , transport and feed a plurality of labels to the carousel at an application station, in order to apply such labels to the respective articles .

[0010] According to a well-known configuration, a labelling module typically comprises :

[0011] - one or more spools around which the web of labelling material is initially wound in form of a continuous reel ;

[0012] - a feed roller for unwinding the web of f the reel and advance it along a feed path;

[0013] - a plurality of support rollers , which support , in use , the web progressively unwound from the reel and guide it , in use , along the feed path;

[0014] - a cutting unit for repeatedly cut the web so as to obtain a sequence of labels from the web itsel f ; and

[0015] - a label trans fer device , for example a known vacuum drum configured to receive , retain and advance each label and to feed each label to the carousel , at the application station .

[0016] According to a well-known configuration, rotary-type cutting units are generally used, which comprise a first roller carrying a blade and a second roller carrying a counterblade element , often defined by a slit engageable by the blade or by an elastomeric pad .

[0017] The two rollers are arranged tangentially adj acent to one another and are rotatable about respective axes .

[0018] The relative rotation of the first and second rollers determines a cyclical interaction between the blade and the counterblade element , which ultimately causes the cut of the web .

[0019] As it is known, at least one of the first and second rollers is to be controlled as a function of the production speed and is to be si zed as a function of the label length .

[0020] It is a desire to use the same labelling module for di f ferent formats of label , which can be dif ferent from each other for example for the label length .

[0021] The need of si zing at least one of the first and second rollers as a function of the label length makes the changeover operation cumbersome , because the roller needs to be changed, taking also into account the need of maintaining the synchroni zation with the production speed .

[0022] To this end, single-roller cutting units have been proposed whereby the cutting unit only comprise a single cutting roller carrying the blade , whereas the counterblade element is carried directly by the vacuum drum .

[0023] In detail , the counterblade element is defined by a portion of the vacuum drum .

[0024] In other words , the cutting of the web occurs between the cutting roller and the vacuum drum .

[0025] In such a case , it is essential that the vacuum drum and the single cutting roller, and especially their mutual angular positions and their mutual peripheral velocities , are maintained in perfect sync with one another throughout the labelling process , as even the slightest loss of synchroni zation between these two may lead to damages on the outer lateral surface of the vacuum drum and / or on the blade .

[0026] However, this synchroni zation between vacuum drum and cutting roller requires costly components , maintenance and precision and it may be di f ficult to maintain over time , thereby leading to periodic stops of the labelling process to avoid damages of the components .

[0027] DISCLOSURE OF INVENTION

[0028] It is therefore an obj ect of the present invention to provide a cutting unit which is designed to overcome the above-mentioned drawbacks in a straightforward and low- cost manner .

[0029] This obj ect is achieved by a cutting unit as claimed in the appended independent claim 1 .

[0030] Preferred embodiments of the present invention are laid down in the appended dependent claims .

[0031] BRIEF DESCRIPTION OF THE DRAWINGS

[0032] A non-limiting embodiment of the present invention will be described by way of example with reference to the accompanying drawings , in which :

[0033] Figure 1 is a schematic top view, with parts removed for clarity, of a labelling machine comprising a labelling module according to the present invention;

[0034] Figure 2 is a larger-scale perspective view, with parts removed for clarity, of part of the labelling machine showing the cutting unit from a first angle ;

[0035] Figure 3 is a larger-scale perspective view, with parts removed for clarity, of the cutting unit from a second angle ;

[0036] Figures 4a, 4b and 4c are top views , with parts removed for clarity, of the cutting unit according to the invention during three distinct instants ; and

[0037] Figures 5 and 6 are perspective views , with parts removed for clarity, of the cutting unit during two further respective and distinct instants .

[0038] BEST MODE FOR CARRYING OUT THE INVENTION

[0039] With reference to Figure 1 , number 1 indicates as a whole a labelling machine for labelling articles 2 , such as bottles , flacons , cans or containers of this sort , adapted to contain a pourable product , preferably a pourable food product .

[0040] In particular, labelling machine 1 is configured to apply labels 3 obtained from a web 4 of labelling material onto articles 2 .

[0041] According to this preferred and non-limiting embodiment , labels 3 are glued labels , i . e . strips of labelling material that are cut at predetermined lengths from web 4 and then sprinkled with glue before their application on the respective articles 2 .

[0042] Preferably, web 4 is initially wound around one or more reels 5 ( only one shown in Figure 1 ) in the form of a continuous strip, and is progressively unwound, in use , of f reel 5 .

[0043] As visible in Figure 1 , labelling machine 1 comprises : a conveyor device , preferably a carousel 6 rotatable around a fixed axis (not shown) , pre ferably vertical , and configured to advance a plurality of articles 2 ( only one of which is shown) along an arcshaped labelling path, preferably hori zontal ; and a labelling module 7 ( only partially and schematically shown) , arranged peripherally relatively to carousel 6 and configured to prepare and feed a plurality of labels 3 to the carousel 6 itself at an application station A, in order to apply labels 3 onto respective articles 2.

[0044] Labelling module 7 comprises:

[0045] - a storage unit supporting, in rotatable manner, at least one reel 5;

[0046] - a feed roller 8 for advancing (i.e. feeding) web 4 along a feed path Q, and therefore for progressively unwinding web 4 from reel 5;

[0047] - a plurality of (idle) support rollers 10 (only one of which schematically shown) , which support, in use, the web 4 progressively unwound from reel 5 and guide it along feed path Q;

[0048] - a cutting unit 11 arranged downstream of feed roller 8, along feed path Q, and configured to repeatedly cut web 4 for obtaining a sequence of labels 3; and a label transfer drum 12, rotatable about a (central) rotation axis X and configured to transfer labels 3 to application station A for the application thereof onto respective articles 2.

[0049] It is stated that feed path Q stretches from the reel 5 up to the application station A. In other words, feed path Q is a path along which web 4 is advanced, prior to the cutting thereof, and then along which labels 3 are advanced, after the cutting of web 4. Preferably, drum 12 is defined by a vacuum drum of the known type , which retains labels 3 by means of suction, in a manner known and not described in detail .

[0050] Drum 12 comprises a plurality of receiving sectors 13 ( five , in the preferred embodiment shown) each configured to cyclically receive and retain a respective label 3 .

[0051] In particular, receiving sectors 13 are equipped with vacuum ports 50 ( Figure 6 ) selectively arrangeable in fluid communication with a vacuum source (not shown) , in a manner known and not described in detail .

[0052] Each receiving sector 13 includes a leading pad 13a for retaining a leading edge 3a of label 3 and a trailing pad 13b for retaining a trailing edge 3b of label 3 .

[0053] Furthermore , each receiving sector 13 comprises an interpad region 13c angularly interposed between pads 13a and 13b .

[0054] In light of the above , each label 3 is retained by a receiving sector 13 of drum 12 with its leading edge 3a onto the respective leading pad 13a, with its trailing edge 3b onto the respective trailing pad 13b, and with its intermediate portion onto interpad region 13c .

[0055] Labelling module 7 further comprises a gluing device , in particular a gluing roller 30 , for applying glue onto the labelling material supported by drum 12 , and more speci fically onto the leading edge 3a and trailing edge 3b of each label 3 supported by the respective receiving sector 13 .

[0056] Expediently, gluing roller 30 is peripherally arranged relative to drum 12 so as to be tangent to the outer lateral surface of each pad 13a, 13b for cyclically applying glue to the label portions resting, in use , thereon .

[0057] Cutting unit 11 comprises a first cutting member 14 , which carries a cutting group 15 including a blade 15a, and a second cutting member, which defines a counterblade element for ( cyclically) receiving the blade 15a .

[0058] According to this preferred embodiment shown, cutting unit 11 is of the rotary type .

[0059] In detail , first cutting member 14 is rotatable about a first axis Y and is thereby configured to carry the cutting group 15 in rotation about the first axis Y .

[0060] Similarly, second cutting member 12 is rotatable about a second axis X and is thereby configured to carry the counterblade element in rotation about the second axis X .

[0061] Conveniently, axis X and axis Y are parallel to one another, and preferably vertical .

[0062] Preferably, second cutting member 12 is defined by drum 12 . Hence , the second axis X corresponds to the drum axis X .

[0063] Hence , drum 12 is part of cutting unit 11 , so that the cutting of web 4 occurs between first cutting member 14 and drum 12 . This cutting on the drum 12 allows to have the first cutting member 14 more flexible with respect to possible change of height and / or longitudinal length of the label .

[0064] In particular, drum 12 includes a number of counterblade elements , one for each retaining sector 13 .

[0065] More speci fically, each counterblade element is located at one respective trailing pad 13b .

[0066] Reference will be made in the following to a single retaining sector 13 , and hence to a single trailing pad 13b and to a single counterblade element of drum 12 .

[0067] More precisely, drum 12 includes a first slot 16a, defining the counterblade element .

[0068] In detail , drum 12 includes a plurality of first slots 16a, one for each retaining sector 13 .

[0069] In other words , each first slot 16a is obtained on a label retaining portion of drum 12 .

[0070] In light of the above , drum 12 , i . e . second cutting member 12 includes at least one first slot 16a, in particular a plurality of first slots 16a, one for each trailing pad 13b .

[0071] Furthermore , according to a first aspect of the invention, drum 12 (i.e. second cutting member 12) comprises an abutment wall 17 and a second slot 16b. The second slot 16b is obtained on the abutment wall 17.

[0072] In detail, drum 12 comprises a plurality of second slots 16b, one for each retaining sector 13.

[0073] Hence, drum 12 is rotatable about second axis X and is thereby configured to carry in rotation the first slot 16a and the second slot 16b about second axis X.

[0074] Conveniently, abutment wall 17 is defined by an annular member 18 carried by drum 12.

[0075] In particular, annular member 18, and therefore abutment wall 17, is arranged at a different axial height than the axial height of retaining sectors 13, with respect to second axis X.

[0076] More in particular, abutment wall 17 is arranged below the retaining sectors 13, i.e. axially below retaining sectors 13 relatively to second axis X, as visible in Figure 3.

[0077] According to a second aspect of the invention, cutting group 15 further includes an anti-collision element 15b.

[0078] In detail, anti-collision element 15b is spaced from blade 15a.

[0079] Anti-collision element 15b is carried in rotation by first cutting member 14 about axis Y. The cutting unit 11 is configured for adopting a nominal condition according to which the blade element 15a interacts with the drum 12 by engaging the first slot 16a for cutting the web 4 , and the anti-collision element 15b interacts with the drum 12 by engaging preferably without contact the second slot 16b during said cutting .

[0080] Figures 1 , 2 , 3 and 4A show the instant of cutting while the cutting unit 11 adopts the nominal condition .

[0081] The first cutting member 14 is rotatable about a first axis Y and is thereby configured to carry the cutting group 15 in rotation about the first axis Y . Therefore , the first cutting member 14 is a rotary first cutting member 14 .

[0082] The drum 12 is rotatable about a second axis X and is thereby configured to carry the first slot 16a and the second slot 16b in rotation about the second axis X . The second axis X and the first axis Y are parallel to each other .

[0083] The first cutting member 14 and the drum 12 are configured to mutually rotate so as to determine the cyclical interaction of the blade element 15a with the drum 12 by means of the blade element 15a engaging the first slot 16a, and the cyclical interaction of the anticollision element 15b with the drum 12 by means of the anti collision element 15b engaging the second slot 16b . The cutting unit 11 is configured for adopting a not nominal condition, according to which the anti-collision element 15b interacts with the drum 12 by contacting said abutment wall 17 .

[0084] Figure 4B shows an instant of contact between anticollision element 15b and abutment wall 17 , while the cutting unit 11 is adopting the not nominal condition .

[0085] The cutting group 15 is movable between an operative position and a safety position . The operative position allows the blade element 15a to interact with the drum 12 . In the safety position, the blade element 15a is retracted away from the drum 12 and is prevented from interacting with the drum 12 . At least in the nominal condition, the cutting group 15 adopts the operative position . Also in the not nominal condition of the cutting unit 11 , the cutting group 15 can adopt the operative position .

[0086] In Figures 1 , 2 , 3 , 4A and 4B, cutting group 15 adopts the operative position . In Figures 1 , 2 , 3 , and 4A, cutting group 15 adopts the operative position while the cutting unit 11 is adopting the nominal condition . In Figure 4B, cutting group 15 adopts the operative position while the cutting unit 11 is adopting the not nominal condition, as will be more clear below . Cutting unit 11 is configured so that , in said not nominal operative condition of the cutting unit 11 , the contact between said abutment wall 17 and said anti collision element 15b triggers a first displacement of the cutting group 15 from the operative position to the safety position . In Figure 4B, the anti collision element 15b is abutting against abutment wall 17 because the cutting unit 11 is adopting the not nominal condition, but the cutting group 15 is still in the operative position .

[0087] In Figures 4C, 5 and 6 , the cutting group 15 is adopting the safety position . In particular, in Figure 4C the cutting group 15 has j ust switched from the operative position to the safety position .

[0088] The first cutting member 14 comprises magnetic means 22 to lock the cutting group 15 selectively in the operative position or in the safety position .

[0089] The first cutting member 14 comprises a first magnetic element 22a and a second magnetic element 22b . The first magnetic element 22a is configured to interact with the cutting group 15 for retaining the cutting group 15 in the operative position . The second magnetic element 22b is configured to interact with the cutting group 15 for retaining the cutting group 15 in the safety position .

[0090] In detail , magnetic means 22 lock the cutting group 15 in the operative position until said non nominal operative condition establishes , and the anti-collision element 15b contacts the abutment wall 17 .

[0091] As soon as this contact occurs , the pression of the anti-collision element 15b against the abutment wall 17 causes an overcome of the magnetic force locking the cutting group 15 to the first magnetic element 22a, thereby determining the first displacement of the cutting group 15 , i . e . its rotation about hinge 19 , towards the safety position .

[0092] The presence of the magnetic means 22 allows for a stable positioning and locking of the cutting group 15 in the operative position and in the safety position, thereby avoiding undesired displacement of the cutting group 15 , and hence of the blade 15a, especially during the nominal operative condition, which could be detrimental to the nominal functioning of cutting unit 11 .

[0093] In detail , magnetic means 22 lock the cutting group 15 in the operative position until said not nominal operative condition establishes and the anti-collision element 15b contacts the abutment wall 17 .

[0094] It is speci fied that said nominal operative condition corresponds to an operative condition whereby the first cutting member 14 and the drum 12 are in a correct synchroni zation with one another for cutting the web . In this condition, the blade 15a cyclically interacts with first slot 16a and anti-collision element 15b cyclically interacts , preferably without contact , with second slot 16b .

[0095] Instead, said not nominal operative condition corresponds to a synchroni zation, between the first cutting member 14 and the drum 12 , which is not correct for the cutting, which can be considered a desynchroni zation .

[0096] In this condition, the cyclical interaction between the anti-collision element 15b and the second slot 16b does not occur properly, and the anti-collision element 15b encounters instead the abutment wall 17 ( Figure 4b ) , to trigger said first displacement . In this way the not correct synchroni zation is used to prevent the blade 15a from incorrectly contacting the drum 12 , to reduce or eliminate the risk of damage for the blade 15a itsel f and for the drum 12 .

[0097] In detail , during said non-nominal operative condition, the anti-collision element 15b presses against abutment wall 17 , thereby triggering the aforesaid first displacement .

[0098] Thanks to the presence of anti-collision element 15b as described above , it is possible to avoid damages to the blade 15a and the drum 12 in the event that correct synchroni zation for cutting between the first cutting member 14 and drum 12 is lost . Therefore , a more ef ficient cutting unit 11 is provided, which has a signi ficantly lower risk of being damaged .

[0099] In particular, an undesired contact between the blade 15a and drum 12 can be avoided .

[0100] In this way, wear is highly reduced and the li fespan of labelling module 7 is increased .

[0101] In light of the above , anti-collision element 15b defines a pressing member adapted to press against abutment wall 17 , during said non-nominal operative condition .

[0102] Conveniently, anti-collision element 15b is made of elastomeric material , in order to reduce wear on abutment wall 17 and reducing the need for maintenance or substitution of annular member 18 .

[0103] Alternatively, anti-collision element 15b could be made of rigid material , for example rigid plastic .

[0104] Cutting group 15 is rotatable about a hinge 19 between the operative position and the safety position . The cutting unit 11 is configured so that , in said not nominal operative condition, the anti-collision element 15b abuts against the abutment wall 17 thereby generating a rotation of the cutting group 15 about said hinge 19 , for causing said first displacement as a first rotational movement of the cutting group 15 around said hinge 19 .

[0105] In this way, the switching of the cutting group 15 between the operative position and the safety position is very quick and / or the compactness of the cutting unit 11 is optimi zed . Moreover, in this way said switching is compatible with a rotary first cutting member 14 .

[0106] Expediently, hinge 19 is parallel to first axis Y, and therefore also to second axis X .

[0107] The cutting unit 11 comprises an actuator 20 configured for triggering a second displacement of the cutting group 15 from the safety position to the operative position .

[0108] The actuator 20 includes a pin 21 movable along a direction parallel to the first axis Y and configured to be axially driven between an inactive position, whereby the pin 21 does not interfere with the rotation of the cutting group 15 about the first axis Y, and an active position, whereby the pin 21 interacts in contact with the cutting group 15 upon rotation of the cutting group 15 about the first axis Y, for causing said second displacement as a second rotational movement of the cutting group 15 around said hinge 19 . The second rotational movement is in the opposite direction with respect to the above mentioned first rotational movement . In Figure 5 the pin 21 adopts the inactive position . In Figure 6 , the pin 21 adopts the active position .

[0109] Pin 21 is axially extractable in the active position to get in the way of the cutting group 15 , so that when cutting group 15 rotates about first axis Y and encounters pin 21 , it is displaced back in its operative position .

[0110] In this way, the automatic restoration of the position of cutting group 15 can be made more simple , reducing the need of a manual intervention by an operator . The rotational movement of the first cutting member 14 , in this way, is used to restore the operative position of the cutting group 15 , to reduce the mechanical complexity of the cutting unit 11 .

[0111] Moreover, the risk of error is signi ficantly reduced .

[0112] As visible in the appended Figures , the blade 15a and the anti-collision element 15b extend radially with respect to first axis Y, at least in said operative position of the cutting group 15 . However, there can be an of fset between any one of the blade 15a and anti collision element 15b, and the first axis Y . Each of the blade 15a and the anti collision element 15b extends radially in the sense that at least one component of their extension is along the radial direction with respect to first axis Y .

[0113] According to one aspect of the invention, at least in said operative position of the cutting group 15 , the anti-collision element 15b radially protrudes more than the blade 15a, with respect to first axis Y .

[0114] In this way, the anti-collision element 15b can contact the drum 12 , and in particular the abutment wall 17 , without the blade 15a contacting the drum 12 . This simpli fies the structure of the drum 12 , allowing a reduction of the radial footprint of the drum 12 .

[0115] In addition, such arrangement further reduces the risk, and in particular eliminates the risk, that that the blade 15a contacts the drum 12 before the anticollision element 15b contacts the abutment wall 17 , during said not nominal operative condition .

[0116] Conveniently, the anti-collision element 15b is arranged at an axial height dif ferent than the axial height of the blade 15a, with respect to first axis Y .

[0117] This is particularly visible in Figure 3 .

[0118] In this way, the anti-collision element 15b does not interfere with possible format change of the labels 3 . Accordingly, i f a format change entails a variation of the longitudinal length of the labels 3 and / or of a height or width of the labels 3 , the anti-collision element can still operate nominally without the need for varying its position . In other words , the position of the anticollision element 15b is independent from the label length and also in general from the label format .

[0119] Advantageously, the blade 15a and the anti-collision element 15b are located ( i . e . fixed) on cutting group 15 at di f ferent respective angular positions with respect to first axis Y .

[0120] The Applicant has observed that this configuration further reduces the risk of the blade 15a contacting the drum 12 during said not nominal operative condition .

[0121] Opportunely, the second slot 16b is obtained at an axial height di f ferent than the axial height of the first slot 16a, with respect to second axis X .

[0122] Moreover, the first slot 16a and the second slot 16b are located at di f ferent respective angular positions with respect to second axis X . In this way, the position of the slots 16a and 16b is such to accommodate the blade 15a and the anti-collision element 15b, during said nominal operative condition .

[0123] Preferably, the anti-collision element 15b is arranged upstream of the blade 15a, with respect to an angular direction of rotation of the cutting group 15 , i . e . of the first cutting member 14 , about first axis Y .

[0124] The Applicant has observed that this configuration even further reduces the risk of the blade 15a contacting the drum 12 during said non-nominal operative condition, since , during said non-nominal operative condition, the anti-collision element 15b will surely come into contact with drum 12 before blade 15a does .

[0125] Alternatively, the blade 15a and the anticollision element 15b are at the same angular position with respect to first axis Y, and first slot 16a and second slot 16b are at the same angular position with respect to second axis X . In this case , blade 15a and anti collision element 15b would be at di f ferent axial heights along first axis Y, and first slot 16a and second slot 16b would be at di f ferent axial heights along second axis X .

[0126] In one preferred embodiment , each first slot 16a is inclined, at least on a plane of rotation of drum 12 , with respect to the radial direction relative to second axis X . That is , the direction of extension of each first slot 16a has at least a component which is transversal to the radial direction and to a direction orthogonal to the radial direction, with respect second axis X . Thanks to the first slot 16a being inclined, the position of the blade 15a with respect to the web 4 during the cutting is improved, to improve the precision of the cutting operation . In particular, the inclination reduces the amount of not needed (namely undesired) contact between the blade 15a and the web 4 .

[0127] In one preferred embodiment , the blade 15a is of fset , at least on a plane of rotation of first cutting member 14 , with respect to the radial direction relative to axis

[0128] Y . This configuration allows to have the blade 15a being more adapted geometrically to the inclination of the first slots 16a . In addition, this of fset permits that during the ef fective cutting of the web 4 , the blade 15a is substantially orthogonal to the web 4 . The of fset improves signi ficantly the quality of cutting, also in case the first slots 16a were not inclined, thanks to a better position of the blade 15a in the instant of cutting . Therefore , the of fset of the blade 15a, despite the presence of an inclined first slot 16a, improves the precision of the cutting operation . In particular, the of fset reduces the amount of not needed (namely undesired) contact between the blade 15a and the web 4 . An inclined first slot 16a allows for improving this ef fect . The inclination of the first slots 16a allows for adapting each first slot 16a to the of fset of the blade 15a .

[0129] In one preferred embodiment , due the aforementioned of fset of the blade 15a, the blade 15a is also inclined with respect to the radial direction relative to axis Y with a first angle . The first angle is comprised between the radial direction relative to axis Y and an imaginary line ( or symmetry line ) passing through the center line of the blade 15a . The blade 15a can be considered a cutting edge or a cutting tip . Each first slot 16a is inclined with respect to the radial direction relative to axis X of drum 12 by a second angle , the value of which falls preferably within the range from 20 ° to 40 ° , more preferably between 25 ° and 35 ° . In this way, the ef fect of having an improved position of the blade 15a with respect to the web 4 can be obtained while minimi zing at the same time the local stress or stretching of the web 4 . The value of inclination of first slots 16a with respect to the radial direction relative to axis X of the drum 12 can be for example 30 ° . The second angle is comprised between the radial direction relative to axis X of the drum 12 and an imaginary line passing through the center line ( or symmetry line ) of the first slot 16a and preferably being parallel to the lateral walls of the first slot 16a itsel f .

[0130] In this way, during cutting of the web 4 , the blade 5a and the first slot 16a are engaged and are substantially aligned one to the other, permitting thus to improve the cutting precision .

[0131] The cutting unit 11 is configured so that the blade 15a is inclined, while cutting the web 4 , by a third angle with respect to the radial direction relative to axis X of the drum 12 , for engaging the blade 15a itsel f in the first slot 16a . The third angle is comprised between the radial direction relative to axis X of the drum 12 and the imaginary line passing through the center line of the blade 15a at the cutting instant . In one embodiment , the third angle may be null or zero .

[0132] Preferably, cutting group 15 further comprises a stopping member 15c to press the web 4 against the trailing pad 13b during the cut of the web 4 itsel f . The stopping member 15c is thus carried in rotation by the first cutting member 14 . The stopping member 15c can be flexible and / or elastic . The stopping member 15c can be made by an elastomeric or elastic material .

[0133] The stopping member 15c is located downstream of the blade 14 , with respect to said direction of rotation of the first cutting member 14 ( and according to an observer which is not moving with the first cutting member 14 ) . In this way it is avoided an interference between the stopping member 15c and a possible sliding of the web 4 on the drum 12 after the cutting, to improve the quality of the web 4 . In fact , there may be the need of having such sliding to adapt the pitch of the labels 3 to the pitch of the articles 2 being conveyed by the carousel 6 .

[0134] The use of a cutting unit 11 operating on the drum 12 allows the feed roller 8 to be located radially adj acent to the drum 12 , to improve the compactness of the module 7 . In one preferred embodiment , each receiving sector

[0135] 13 is removable and interchangeable with a receiving sector 13 of a di f ferent type and variable depending on the format of the labels 3 to be applied, so that the number of receiving sectors 13 can also be changed .

[0136] In one preferred embodiment , each trailing pad 13b with the respective first slot 16a is removable and interchangeable together with the respective receiving sector 13 .

[0137] The advantages of cutting unit 11 according to the present invention will be clear from the foregoing description .

[0138] In particular, thanks to the presence of anticollision element 15b as described above , it is possible to avoid damages to the blade 15a and the drum 12 in the event that synchroni zation between the first cutting member 14 and drum 12 is lost .

[0139] In particular, an undesired contact between the blade 15a and drum 12 can be avoided .

[0140] In this way, wear is highly reduced and the li fespan of labelling module 7 is increased .

[0141] Furthermore , the need for periodic stops for avoiding such damages to the blade 15a and / or the drum 12 is signi ficantly reduced, thereby ensuring a smoother labelling process . Clearly, changes may be made to cutting unit 11 and to labelling machine 1 as described herein without , however, departing from the scope of protection as defined in the accompanying claims . In particular, the first cutting member 14 may include more than one cutting groups 15, for example two cutting groups 15 as visible in the appended Figures . In this way, the angular speed of the first cutting member 14 may be maintained lower than in case only a single cutting group 15 is present, with advantages concerning the inertia of the system.

Claims

CLAIMS1.- Cutting unit (11) configured to cut a web (4) of labelling material for obtaining a sequence of labels (3) to be applied onto articles (2) adapted to contain a pourable product, the cutting unit (11) comprising: a first cutting member (14) , which carries a cutting group (15) including a blade element (15a) and an anti-collision element (15b) ; and- a second cutting member (12) , which includes a first slot (16a) , an abutment wall (17) and a second slot (16b) which is preferably obtained on the abutment wall (17) ; wherein the cutting unit (11) is configured for adopting a nominal condition according to which the blade element (15a) interacts with the second cutting member (12) by engaging the first slot (16a) for cutting the web (4) , and the anti-collision element (15b) interacts with the second cutting member (12) by engaging preferably without contact the second slot (16b) during said cutting; wherein the cutting unit (11) is configured for adopting a not nominal condition, according to which the anti-collision element (15b) interacts with the second cutting member (12) by contacting said abutment wall (17) .2.- Cutting unit as claimed in claim 1, wherein the cutting group (15) is movable between an operativeposition, whereby the blade element (15a) is allowed to interact with the second cutting member (12) , and a safety position, whereby the blade element (15a) is operatively retracted away from the second cutting member (12) to be prevented from interacting with the second cutting member (12) , at least the nominal condition of the cutting unit (11) corresponding to the operative position of the cutting group (15) ; wherein the cutting unit (11) is configured so that, in said not nominal operative condition, the contact between said abutment wall (17) and said anti collision element (15b) triggers a first displacement of the cutting group (15) from the operative position to the safety position .3.- Cutting unit as claimed in Claim 2, wherein the first cutting member (14) comprises magnetic means (22) to lock the cutting group (15) selectively in the operative position or in the safety position.4.- Cutting unit as claimed in claim 3, wherein the first cutting member (14) comprises a first magnetic element (22a) and a second magnetic element (22b) , the first magnetic element (22a) being configured to interact with the cutting group (15) for retaining the cutting group (15) in the operative position, the second magnetic element (22b) being configured to interact with thecutting group (15) for retaining the cutting group (15) in the safety position.5.- Cutting unit as claimed in any of claims from 2 to 4, wherein the cutting group (15) is rotatable about a hinge (19) between the operative position and the safety position, the cutting unit (11) being configured so that, in said not nominal operative condition, the anticollision element (15b) abuts against the abutment wall (17) thereby generating a rotation of the cutting group (15) about said hinge (19) , for causing said first displacement as a first rotational movement of the cutting group (15) around said hinge (19) .6.- Cutting unit as claimed in any of the previous Claims, wherein the first cutting member (14) is rotatable about a first axis (Y) and is thereby configured to carry the cutting group (15) in rotation about the first axis (Y) .7 Cutting unit as claimed in claims 5 and 6, comprising an actuator (20) configured for triggering a second displacement of the cutting group (15) from the safety position to the operative position; wherein the actuator (20) includes a pin (21) movable between an inactive position, whereby the pin (21) does not interfere with the rotation of the cutting group (15) about the first axis (Y) , and an active position, wherebythe pin (21) interacts in contact with the cutting group (15) upon rotation of the cutting group (15) about the first axis (Y) , for causing said second displacement as a second rotational movement around said hinge (19) , said second rotational movement being in the opposite direction with respect to said first rotational movement.8.- Cutting unit as claimed in claims 6 and 7, wherein the second cutting member (12) is rotatable about a second axis (X) and is thereby configured to carry the first slot (16a) and the second slot (16b) in rotation about the second axis (X) , wherein the first cutting member (14) and the second cutting member (12) are configured to mutually rotate so as to determine the cyclical interaction of the blade element (15a) with the second cutting member (12) by engaging the first slot (16a) , and the cyclical interaction of the anti-collision element (15b) with the second cutting member (12) by engaging the second slot (16b) , the second axis (X) and the first axis (Y) being preferably parallel to each other.9.- Cutting unit as claimed in Claim 8, wherein the second cutting member (14) is defined by a label transfer drum (12) rotatable about the second axis (X) and configured for retaining labels (3) , transferring the labels (3) to an application station (A) , and applyingthe labels (3) at the application station (A) on respective articles (2) ; wherein the first slot (16a) is obtained on a label retaining portion (13, 13b) of the label transfer drum (12) ; and wherein said abutment wall (17) is arranged at a different axial height than the axial height of said label retaining portion (13, 13b) , with respect to said second axis (X) .10.- Cutting unit as claimed in any of Claims from 6 to 9, wherein, at least in said operative position of the cutting group, the anti-collision element (15b) radially protrudes more than the blade element (15a) , with respect to the first axis (Y) .11.- Cutting unit as claimed in any of claims from 6 to 10, wherein the anti-collision element (15b) is arranged at an axial height different than the axial height of the blade element (15a) , with respect to said first axis (Y) .12.- Cutting unit as claimed in any of claims from 6 to 11, wherein the blade element (15a) and the anticollision element (15b) are located at different respective angular positions with respect to said first axis (Y) .13.- Cutting unit as claimed in claim 12, whereinthe anti-collision element (15b) is arranged upstream of the blade element (15a) , with respect to an angular direction of rotation of the cutting group (15) about the first axis (Y) .14.- Labelling module (7) for labelling articles (3) adapted to contain a pourable product, the labelling module (7) comprising:- a storage unit for storing a continuous web (4) of labelling material;- a feed roller (8) for advancing the web (4) along a feed path (Q) ;- a cutting unit (11) as claimed in any one of the foregoing claims, the cutting unit (11) being arranged downstream of the feed roller (8) and being configured for repeatedly cutting the web (4) for obtaining a sequence of labels (3) ;- a label transfer drum (12) for transferring the labels (3) at an application station (A) for the application thereof onto the respective articles (2) , the second cutting member (12) being defined by the drum (12) .15.- Labelling machine (1) for labelling articles (2) adapted to contain a pourable product, the labelling machine (1) comprising:- a conveyor (6) for conveying a sequence of articles(2) ;- a labelling module (7) as claimed in claim 14 and configured to label the articles (2) being conveyed by the conveyor (6) .

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