Abstract:
A stationary blade assembly for cutting labels from a label film in labelling machines, including: a support, a blade supported by said support; blade, a pair of first surfaces interposed between a second surface and a corresponding third surface transversal to the second surface. The stationary blade includes at least two cutting edges which are adapted to cut said labels.

Description:
RELATED APPLICATIONS 
     This application is a U.S. National Stage Filing under 35 U.S.C. 371 from International Application No. PCT/EP2012/052358, filed on Feb. 10, 2012, and published as WO 2012/107583 A1 on Aug. 16, 2012, which claims the benefit under 35 U.S.C. 119 to Italian Application No. TO2011U000008, filed on Feb. 11, 2011; which applications and publication are incorporated herein by reference in their entirety. 
     TECHNICAL FIELD 
     The present innovation relates to a stationary blade assembly. 
     BACKGROUND ART 
     Labelling machines are known, especially of the kind that use a label reel from which labels are cut and applied onto articles, in particular articles filled with a pourable food product. 
     The above-identified machines, known as roll fed labelling machines, substantially comprise a carousel for advancing the articles along a path, and a labelling unit which applies a plurality of labels onto relative articles along the path. 
     In detail, the labelling unit comprises:
         at least one motorized feeding roll for moving a strip of label from a label reel towards the carousel;   a cutting unit for cutting a label of a given length from the label strip; and   a vacuum suction drum which receives the cut labels and transfers the labels to the articles in the carousel.       

     Cutting unit comprises a rotary blade assembly and a stationary blade assembly which are positioned adjacent to the vacuum suction drum. 
     More precisely, rotary blade comprises a rotating drum and one or more cutting edges arranged at an outer periphery of the rotating drum. 
     Stationary blade assembly comprises a support and a blade which projects outwards from the support. 
     The label strip is taken at its free end by suction by the vacuum drum, and passes between the stationary and the rotary blade of the cutting unit. 
     More precisely, since the vacuum drum rotates an higher speed than the label strip speed, the vacuum drum pulls an end of the label strip. 
     The label strip thus passes within a passage which is defined by the rotary and stationary blades. When the rotary and stationary blades face each other, a label is cut and separated by the vacuum drum from the remaining part of the label strip. 
     Stationary blade is generally pentagonal or triangular in section and comprises only one cutting edge. 
     Furthermore, stationary blade is generally made in a softer material than the rotary blade. 
     The rotary blades are commonly square with multiple useable edges. 
     Furthermore, the rotary blades are commonly made of a harder material such as carbide to resist wearing from the label sliding across the cutting edge. 
     Accordingly, the stationary blade needs to be changed more often than the rotary blade. 
     A need is felt within the industry to reduce the time and the costs connected with the stationary blade replacement, so as to increase the throughput of the labelling machine. 
     DISCLOSURE OF INVENTION 
     It is an object of the present innovation to provide a stationary blade assembly, designed to meet the above-identified requirement. 
     According to the present innovation, there is provided a stationary blade assembly, as claimed in claim  1 . 
     SUMMARY 
     Examples of the present subject matter provide a stationary blade assembly, designed to meet the above-identified requirement. 
     According to the present subject matter, there is provided a stationary blade assembly, as claimed in claim  1 . 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A non-limiting embodiment of the present subject matter will be described by way of example with reference to the accompanying drawings, in which: 
         FIG. 1  shows a schematic top view of a cutting unit which comprises a stationary blade assembly according to a first embodiment; 
         FIG. 2  is an enlarged view of some components of the cutting unit of  FIG. 1 ; and 
         FIG. 3  shows, in an enlarged view, a section of stationary blade assembly according to a second embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Number  1  in  FIG. 1  indicates as a whole a cutting unit for cutting a label  5  from a labels strip  6 . 
     Cutting unit  1  is adapted to be incorporated into a labeling machine, especially into a roll-fed labeling machine for applying labels  5  to relative articles, in particular containers filled with pourable product. 
     In detail, the roll-fed labeling machine (not shown) substantially comprises:
         a label reel from which label strip  6  is unwound along a path A from a motorized roll;   a carrousel for advancing articles along an additional curved path; and   a labeling unit for applying labels  5  onto relative articles which are advanced by carousel.       

     Labeling machine also comprises at least one feeding roll for moving labels strip  6  from reel towards carousel. 
     Cutting unit  1  cuts label  5  from strip  6  and conveys them towards carousel. 
     Cutting unit  1  substantially comprises:
         a drum  2  which rotates about an axis B;   a stationary blade assembly  3  adapted to interact with drum  2  to separate a label  5  from label strip  6 ; and   a vacuum-suction drum  4  adapted to advance each cut label  5  which has been separated from the remaining part of the label strip  6 .       

     In detail, drum  2  comprises a cylindrical main body  7  and a blade  8  which outwardly protrudes from an outer periphery  12  of body  7 . Blade  8  is provided with a cutting edge  39 . 
     Drum  2  could also comprise a plurality of blades  8 . 
     Assembly  3  comprises a support  9 , and a blade  10  which protrudes outwardly from support  9 . 
     Blade  10  and outer periphery  12  of body  7  define a passage  15  for the label strip  6 . 
     At a given angular position of drum  2  shown in  FIG. 1 , the operational edges of blade  8  and blade  10  face each other at close proximity or with minimal contact with a consequent cutting action. 
     In such a condition, blades  8 ,  10  cut label  5  and separate it from label strip  6 . 
     Vacuum suction drum  4  rotates about an axis D parallel to axis B and conveys cut label  5  towards carousel by means of vacuum applied onto such a cut label  5 . 
     Blade  10  advantageously comprises a plurality of cutting edges  11   a ,  11   b ,  11   c ,  11   d , four in the embodiment shown. 
     In particular, blade  10  comprises ( FIG. 2 ):
         a pair of rectangular clamping surfaces  16  opposite to and parallel each other; and   a pair of rectangular locating surfaces  17  opposite to and parallel each other.       

     Blade  10  also comprises, proceeding from one surface  17  to one of the surfaces  17  adjacent thereto:
         a surface  60  transversal to surface  16 ;   a surface  50  orthogonal to surface  60 ;   a surface  51  orthogonal to surface  50 ; and   a surface  61  orthogonal to surface  51 .       

     Surfaces  61 ,  50 ;  50 ,  51 ; and  51 ,  60  are orthogonal to each other. 
     Surfaces  61 ,  50 ,  51 ,  60  are finished by using a grinding wheel. 
     Each pair of surfaces  50 ,  51  adjacent to each other are sharply joined so as to form a relative cutting edge  11   a ,  11   b ,  11   c ,  11   d.    
     Surfaces  61 ,  51 ;  50 ,  60  adjacent to each other are sharply joined to each other. 
     Surfaces  60  originate from a relative surface  16  and diverge from each other, starting from the relative surface  16 . 
     Surfaces  61  originate from a relative surface  17  and converge towards each other, starting from the relative surface  17 . 
     Surfaces  16  have a symmetry axis C. 
     Surfaces  17  have a symmetry axis Y orthogonal to axis C. 
     Cutting edges  11   a ,  11   b ,  11   c ,  11   d  are slightly inclined relative to an axis X, which is orthogonal to axes C, Y. 
     Cutting edges  11   a ,  11   b ,  11   c ,  11   d  are also inclined relative to cutting edge  39  of blade  8 . 
     Blade assembly  3  comprises a plurality of releasable connecting elements  13  for connecting surfaces  16  to support  9  ( FIG. 1 ). 
     Connecting elements  13  consist, in the embodiment shown, of five to nine screws. 
     In particular, surfaces  16  defines a plurality of holes  14  engaged by relative connecting elements  13 . 
     Connecting elements  13  have shanks which pass through respective holes  14  with play. 
     Holes  14  have their own axes which are parallel to axis C. 
     Support element  9  comprises a main body  20  and an appendix  21  which protrudes from body  20  ( FIG. 1 ). 
     Body  20  is bounded by a wall  29  which cooperates with one surface  16  of blade  10  and onto which connecting elements  13  are screwed. 
     Appendix  21  protrudes from wall  29  on the opposite side of body  20 . 
     Blade assembly  3  also comprises regulating means to stabilize the final position of blade  10  after contact adjustment 
     Regulating means comprise, in the embodiment shown:
         a jacking screw  30  which pass through appendix  21  and cooperates with one of surfaces  17  of blade  10 ; and   a locking nut  31  coupled with screw  30 .       

     The operation of blade assembly  3  is described starting from a configuration, in which cutting edge  11   c  is in the cutting area. 
     Label strip  6  is unwound from label reel and advanced along a path A by the motorized roll. 
     Label strip  6  is taken up at its end by suction by vacuum suction drum  4 , and advanced within passage  15  which is defined, on its opposite sides, by cutting edge  11   c  and outer periphery  12 . 
     Due to the rotation of drum  2  about axis B, at a certain time, blade  8  faces cutting edge  11   c  of blade  10  of assembly  3  and closes passage  15  with such blade  8 . 
     In such a position shown in  FIG. 1 , one label  5  is cut from the remaining part of label strip  6  by the actions of cutting edges  11   c ,  39  of blades  8  and of blade  10 . 
     Due to the fact that cutting edges  11   c ,  39  are slanted relative to each other, the cutting action is progressive. 
     Cut label  5  is then conveyed by the suction action of vacuum suction drum  4  towards the carrousel where it is applied onto a relative article by the labelling group. 
     After that edge  11   c  has cut a given number of labels  5 , edge  11   c  becomes worn out or blunted. At this stage, connecting elements  13  are released from support  9 , blade  10  is rotated so as to use edge  11   a  to cut labels  5 . 
     With reference to  FIG. 2 , blade  10  is rotated about axis X of 180 degrees, so as to arrange edge  11   b  in front of drum  2  in the cutting area. 
     At this stage, blade  10  is connected again to support  9 , by using the connecting elements  13 . 
     Once that also edge  11   b  is worn out or blunted, blade  10  is disconnected by support  9 , rotated about axis Y of 180 degrees, so as to arrange cutting edge  11   d  in front of drum  2  in the cutting area. 
     At this stage, blade  10  is connected again to support element  9  by using connecting elements  13 . 
     Finally, once that also edge  11   d  is worn out or blunted, blade  10  is rotated about axis X of 180 degrees, so as to arrange edge  11   a  in front of drum  2  in the cutting area. 
     Number  3 ′ in  FIG. 3  indicates a second embodiment of a blade assembly in accordance with the present subject matter; blade assembly  3 .  3 ′ being similar to each other, the following description is limited to the differences between them, and using the same references, where possible, for identical or corresponding parts. 
     Blade assembly  3 ′ differs from blade assembly  3  in that support element  9 ′ comprises multiple rounded end arm  40 ′. 
     Arm  40 ′ has, at an its end close to the vacuum suction drum  4  and drum  2 , a seat  41 ′ engaging blade  8 . 
     Seat  41 ′ comprises a pair of flat walls  42 ′ facing to each other and lying on a plane parallel to axis C, and by a wall  43 ′ lying on a plane orthogonal to axis C. 
     Wall  43 ′ cooperates with surface  16  of blade  10 ′ and walls  42 ′ cooperate respectively with surfaces  17  of blade  10 ′. 
     Connecting elements  13 ′ are partly housed within holes  14 ′ of blade  10  and partly housed within relative holes  46 ′ defined by end arm  40 ′. 
     The length of wall  43 ′ orthogonally to axis C is higher than the length of walls  42 ′ parallel to axis C. 
     The operation of blade assembly  3 ′ is similar to the operation of blade assembly  3  and is not described in detail. 
     From an analysis of the features of stationary blade assembly  3 ,  3 ′ according to the present subject matter, the advantages it achieves to obtain are apparent. 
     In particular, blade assembly  3 ,  3 ′ comprises a blade  10 ,  10 ′ with more than one cutting edge  11   a ,  11   b ,  11   c ,  11   d.    
     The cutting edge which is effective in cutting labels  5  may be easily changed by simply rotating blade  10 ,  10 ′ of 180 degrees about axis X or axis Y. 
     As a result, the life of blade  10 ,  10 ′ is extended when compared with the solution described in the introductory part of the present description. 
     Furthermore, the time losses and the costs connected with the replacement of blade  10  are reduced, so as to increase the throughput of the labelling machine. 
     In addition, due to the fact that edges  11   c ,  39  are slanted relative to each other, the cutting action is progressive. 
     Finally, it is apparent that modifications and variants not departing from the scope of protection of the claims may be made to stationary blade assembly  3 ,  3 ′.