Patent Publication Number: US-2023150163-A1

Title: Knife for cutting capsules

Description:
The invention relates to a knife for cutting capsules or closures or caps made of plastic of the type used for closing containers, such as for example bottles. In particular the invention relates to a knife arranged for cutting the side wall of a capsule, so as to obtain—on such side wall—an tamper strip or ring and one or more connecting portions, also known as braces or hinges, which connect the tamper strip or ring to a different portion of the capsule, for example to the skirt, i.e. a portion of the side wall having a closed end of the capsule. 
     Designing objects made of plastics is increasingly oriented toward the choice of recyclable materials and toward recovery of the objects after use thereof. Thus, closures provided with braces, which allow to hold the closure on the tamper ring thereof even after the container has been opened, are increasingly on high demand even in the container closures industry. 
     In use, when a cap provided with an tamper strip and with braces is applied to a mouth of a container, such as for example a bottle, to close the container, the tamper strip is positioned in a seat generally defined between two annular protrusions, with which the body of the container is provided, which limit the axial movements of the tamper ring. Upon unscrewing the closure, the container is opened, the tamper strip is held in the seat thereof and the braces hold the capsule joined to the tamper ring, and thus to the bottle, even after the closed end portion of the closure has been moved away from the mouth of the container. 
     This allows an effective recycling of plastics, given that the tamper ring can be separated from the bottle together with the closure at the same time, i.e. when one wants to recover the plastic material of the closure. Furthermore, keeping the closure connected to the tamper ring—even after opening the container—contributes toward preventing the dispersion of the capsule into the environment. 
     The braces on the side wall of a capsule are mainly obtained according to two types of processing operations: by forming, i.e. providing moulds suitably shaped to form the braces; or by cutting, i.e. by providing an arrangement of cuts and incisions on the side wall of the previously formed capsule. The cuts and incisions determine parts of the side wall that are partially detachable from the remainder of the side wall of the capsule, such parts of the side wall defining the connecting portions or braces besides the tamper ring. Techniques for producing braces which combine particular shapes of the mould for forming the capsule and given shapes of cuts obtained on the capsule after forming are also known. 
     Cutting devices comprising knives suitable to cut or incise a capsule in the side wall thereof so as to determine a circumferential line for weakening and preferential separation between the tamper strip and a remainder of the side wall of the capsule, i.e. of the skirt, are known. Such type of cut is also known under the name horizontal cut. 
     Cutting devices suitable to cut and incise—in one or more points or areas—a side wall of the capsule according to a direction substantially parallel to the axis of the capsule, for example so as to obtain weakening areas in the tamper strip or access points for washing means to eliminate residues from the capsule are also known. Such type of cut is also known under the name vertical cut. 
     Cutting devices suitable to incise the side wall both with a horizontal cut and with a vertical cut in a radial position of the capsule, are also known. The latter cutting devices generally comprise a knife for the horizontal cut, positioned downstream of which is an insert provided with a vertical blade for incising the capsule by means of a vertical cut. 
     Cutting devices having knives comprising a variety of blades to obtain the connecting portions or braces, are also known. 
     The various cutting devices described above are provided with knives manufactured for specific cutting geometries and for specific dimensions of the capsule. This entails that the producer of capsules must procure and store in the warehouse thereof numerous knives with which to equip the cutting device whenever there arises the need to change the capsule production batch. Furthermore, having to equip the cutting device with a new knife requires considerable machine downtime and this entails high production costs. Furthermore, the knives used to obtain the braces are structurally complex, requiring a high number of parts which will then have to be replaced once worn, hence manufacturing caps with such complex structures increases the production costs. 
     An object of the invention is to improve the knives of the known type for capsule cutting apparatus. 
     Another object of the invention is to provide a knife for a capsule cutting apparatus for performing the incision on the braces or other elements on side walls of plastic capsules and having a relatively simple structure. 
     A further object of the invention is to provide a knife that is more versatile than the known knives that can be used, with slight variations, for incising various cutting geometries. 
     According to the invention a knife as defined by the attached claims is provided. 
     Owing to the invention it is possible to provide a knife with a layered structure that performs incisions—having a more or less complex geometry—by superimposing cutting tools whose cutting profiles are arranged according to different tilts. 
     Owing to the invention it is possible to provide one or more assembly configurations which allow to vary the cutting geometry to be applied to the capsules by adding and/or replacing cutting tools in the layered structure. 
     This allows to vary the geometry of the cut using the same knife or replacing a limited number of components therein. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention can be better understood and carried into effect with reference to the attached drawings, in which some embodiments of the invention are shown by way of non-limiting examples, wherein: 
         FIG.  1    is a perspective view of a first embodiment of a knife for cutting capsules; 
         FIG.  1 A  is a plan partial view of the knife of  FIG.  1   , illustrating two through holes; 
         FIG.  2    is a detail of  FIG.  1   , illustrating a first cutting tool, a second cutting tool and a third cutting tool; 
         FIG.  3    is a detail of  FIG.  1   , showing the first cutting tool; 
         FIG.  4    is a detail of  FIG.  1   , showing the second cutting tool; 
         FIG.  5    is a detail of  FIG.  1   , showing the third cutting tool; 
         FIG.  6    is a schematic view of the arrangement of blades of the knife of  FIG.  1   ; 
         FIG.  7 A  is a cylindrical projection view of a side wall of a capsule incised by the knife of  FIG.  1   , in a closing configuration of the capsule; 
         FIG.  7 B  is a cylindrical projection view of a side wall of a capsule incised by the knife of  FIG.  1   , in an opening configuration of the capsule; 
         FIG.  8    is a schematic view of an arrangement of blades of a knife according to a second embodiment; 
         FIG.  9 A  is cylindrical projection view of a side wall of a capsule incised by the knife having the arrangement of blades of  FIG.  8   , in a closing position of the capsule; 
         FIG.  9 B  is a cylindrical projection view of a side wall of a capsule incised by the knife having the arrangement of blades of  FIG.  8   , in an opening position of the capsule; 
         FIG.  10    is a perspective view of the second embodiment of the knife for cutting capsules having the arrangement of blades of  FIG.  8   ; 
         FIG.  10 A  is a plan partial view of the knife of  FIG.  10   , illustrating two through holes; 
         FIG.  11    is a detail of  FIG.  10   , showing the first cutting tool, the second cutting tool, a further third cutting tool, a fourth cutting tool and a fifth cutting tool; 
         FIG.  12    is a detail of  FIG.  10   , showing the fourth cutting tool and the fifth cutting tool; 
         FIG.  13    is a detail of  FIG.  10   , showing the further third cutting tool. 
     
    
    
     DETAILED DESCRIPTION 
     With reference to  FIGS.  1 - 6 ,  7 A,  7 B , a first embodiment of a knife for incising capsules or caps or closures, i.e. a knife  100  arranged for cutting or incising a side wall  70  of a capsule  7 , is described. The capsule  7  is made of plastics and it is designed to close a container, such as for example a bottle. The capsule  7  has a cup-shaped main body and it is provided with a closed end  8  and with an open end  9 . 
     The knife  100  is arranged for being fitted to a cutting apparatus to obtain incision lines and cuts on the capsule  7 . 
     The word “cut” or “groove” is used to indicate an area of the capsule  7  provided with a perforating cut, i.e. a through slit where the material continuity was interrupted by the action of the knife. The word “incision” is used to indicate an area of the capsule  7  in which the side wall  70  has a low thickness caused by a penetration of the knife into the material up to a given depth without interrupting the material continuity. 
     The knife  100  comprises a first cutting tool  10 , a second cutting tool  20  and a third cutting tool  30 . The knife  100  has a layered structure in which the third cutting tool  30  is arranged between the first cutting tool  10  and the second cutting tool  20 . The first cutting tool  10 , the third cutting tool  30  and the second cutting tool  20  are stacked on each other, in a removable assembly, as will be described hereinafter. The knife  100  is removably fixed to the frame of the cutting apparatus by fastening means, not shown, such as for example screw means or bolt means, which furthermore allow the cutting tools  10 ,  20 ,  30  to be clamped and removably fixed to each other. With reference to  FIG.  1   , each of the cutting tools  10 ,  20 ,  30  comprises, in particular, at least one hole  91 ,  92  of the through type, arranged to receive the fastening means, so that said cutting tools  10 ,  20 ,  30  can be removed or inserted from/into the layered structure, based on the stacking order from top to bottom tool. With reference to  FIG.  1 A , the at least one hole  91 ,  92  can comprise, in particular, at least one eccentric hole, or slot  92 , arranged for allowing a position adjustment of the cutting tools  10 ,  20 ,  30  independently from each other, in particular on a plane parallel to the plane P. The at least one hole  91 ,  92  enables, in particular, the selective removal of each cutting tool  10 ,  20 ,  30  to allow the removal and/or insertion of additional cutting tools, for example, to replace a tool with worn cutting edges or to change the arrangement of the cutting edges. For example, it is possible to replace only the third cutting tool  30 , restoring the layered structure without replacing the first cutting tool or the second cutting tool. 
     The layered structure of the knife  100  defines a cutting portion of the knife  100 , hereinafter indicated as arrangement of cutting edges  60 . In the present description, the expression arrangement of cutting edges is used to indicate an arrangement or group of cutting edges of various shapes and sizes with which the knife is provided which allow the knife to perform cuts and/or incisions on the capsule  7  when the knife  100  is fitted to a cutting apparatus for incising and cutting capsules. 
     With reference to  FIGS.  8 - 13   , a second embodiment of knife, i.e. a knife  100 ′, is illustrated. The difference between the knife  100 ′ and the knife  100  lies in the addition of two cutting tools, i.e. a fourth cutting tool  40  and a fifth cutting tool  50 , and in the replacement of the cutting tool  30  with a further cutting tool  30 ′. Such layered structure defines a cutting portion of the knife  100 ′, i.e. an arrangement of cutting edges  60 ′. 
     The knife  100 ,  100 ′ is suitable to form a tamper strip or ring  72  in the capsule  7  ( FIGS.  7 A,  7 B,  9 A,  9 B ). The knife  100 ,  100 ′ is suitable to form connecting portions  74   a ,  74   b  between the tamper ring  72  and the side wall  70 . The main body of the capsule  7  remains connected to the tamper ring  72  by means of the connecting portions  74   a ,  74   b  even when the capsule  7  is removed from a mouth of the container on which it had been applied to open the container and access the content, i.e. when the capsule is in an opening configuration D ( FIGS.  7 B,  9 B ). 
     The knife  100 ,  100 ′ inside the cutting apparatus cooperates with a rotary spindle (not shown) which grips the capsule  7 , by rotating the capsule around a rotation axis R parallel to or coincident with, an axis of the capsule  7 . The rotary spindle brings the side wall  70  of the capsule  7  into contact with a cutting portion of the knife  100 ,  100 ′, moving the capsule  7  along a substantially circumference arc-like path in an advancement direction T and rotating the capsule  7  on the rotation axis R, by rolling the capsule against the cutting portion of the knife  100 ,  100 ′. As known, possible slipping of the capsule with respect to the spindle or to the cutting portion are undesired. 
     Depending on the arrangement of cutting edges  60 ,  60 ′ of the cutting portion of the knife  100 ,  100 ′, there is a corresponding incision on the side wall  70  of the capsule  7 . In other words, such arrangement of cutting edges  60 ,  60 ′ is shown in a negative fashion on the side wall  70  of a capsule  7 . 
     With reference to  FIGS.  1  and  10   , it should be noted that the advancement direction T and the direction of rotation R of the capsule  7  are only indicative and the effect of the knife  100 ,  100 ′ on the capsule  7  is equal to the one that can be obtained with an advancement direction T and direction of rotation R of the capsule both reversed. 
     With reference to  FIGS.  6 ,  8 ,  7 B,  9 B  the arrangement of cutting edges  60 ,  60 ′ defines in the side wall  70  after the cutting and incision action—the skirt  71  and the tamper strip or ring  72 . In the description below the term “skirt” is associated with the side wall portion  70  having the closed end  8 , while the expression “tamper strip” or “tamper ring” is associated with the side wall portion  70  having the open end  9 , substantially annular-shaped. 
     The skirt  71  and the tamper strip  72  are connected to each other by a plurality of connecting portions or braces  74   a ,  74   b  and by a plurality of bridges  73 , i.e. elements made of plastic material intended to be broken by the user at the first opening of the container on which the capsule  7  is applied to prove the tampering with the closure of the container. 
     With reference particularly to  FIGS.  7 A and  9 A , the capsule  7 , whose side wall  70  is shown unrolled on a representation plane, appears on a closing configuration C wherein the bridges  73 , are whole and contribute together to the braces  74   a ,  74   b  to join the tamper strip  72  to the skirt  71 . The closing configuration C is taken by the capsule prior to being applied to a container or after its application and before the container is opened for the first time and capsule is actuated. 
     With reference particularly to  FIGS.  7 B and  9 B , the capsule  7 , whose side wall  70  is shown unrolled on a representation plane, appears on an opening configuration D wherein the bridges  73  are broken, the skirt  71  is spaced from the tamper strip  72  and the tamper strip  72  is connected to the skirt  71  solely by the braces  74   a ,  74   b . The opening configuration D is taken by the capsule applied to a container and after the first opening of the container from which the capsule is moved away. 
     Once again with reference to  FIGS.  1 - 3    and particularly to  FIG.  3   , the first cutting tool  10  has a plate-like structure, i.e. it mainly extends along two main dimensions with respect to a third transversal dimension, and in particular a rectangular base. The first cutting tool  10  has two flat faces, substantially parallel to each other and with the first plane P: the first lower face  14  and the first upper face  15 . 
     The first cutting tool  10 , in a first peripheral region  17 , comprises a plurality of first blades  11 , for example first blades  11   a ,  11   b ,  11   c , and a plurality of first recesses  16   a ,  16   b . The plurality of first blades  11   a ,  11   b ,  11   c  of the first cutting tool  10  and the first recesses  16  are arranged alternatingly along the first peripheral region  17  of the cutting tool  10 , defining an indented or serrated profile obtained projecting the first cutting tool  10  on the plane P. The first blades  11   a ,  11   b ,  11   c  may comprise one or more first cavities  13  arranged to form the bridges  73 . Furthermore, the first blades  11   a ,  11   b ,  11   c  are provided on the free end thereof with first cutting edges  12   a ,  12   b ,  12   c.    
     The first cutting edges  12   a ,  12   b ,  12   c  lie on the same first plane parallel to the plane P, thus the cutting tool  10  is a horizontal cutting tool. With respect to the plane P, on a vertical axis Z, orthogonal to the plane P, the first plane is at a given height. Joining the plurality of the first cutting edges  12   a ,  12   b ,  12   c  allows to obtain a first substantially circumference arc-shaped curved line whose centre is located outside the knife  100 ,  100 ′ on an axis substantially orthogonal to the plane P. The first cutting tool  10  is arranged to contribute to the formation of braces  74   a ,  74   b  on the side wall  70 , together with the second cutting tool  20  and with the third cutting tool  30 , and it performs the incisions and cuts that separate the skirt  71  form the tamper strip  72 . The first cavities  13  are spaced apart and suitably dimensioned so as not to interrupt the continuity of the material, for example so as not to alter locally or to incise but not perforating the side wall  70  of the capsule, so as to allow to form the bridges  73 . 
     With reference to  FIGS.  1 ,  2  and  4   , the second cutting tool  20  has a plate-like structure, which extends parallel to the plane P, and in particular a rectangular base. The second cutting tool  20  has two flat faces, substantially parallel to each other and to the plane P, i.e. the second lower face  24  and the second upper face  25 . 
     The second cutting tool  20 , in a second peripheral region  27 , comprises a plurality of second blades  21 , including for example second blades  21   a ,  21   b  and a plurality of second recesses  26 . The second blades  21   a ,  21   b  and the second recess  26  are arranged alternatingly along the second peripheral region  27  of the cutting tool  20 , defining an indented profile in an orthogonal projection on the plane P. The second blades  21   a ,  21   b  may comprise one or more second cavities  23  arranged in defined positions in the second blades  21   a ,  21   b . The second blades  21   a ,  21   b  are provided—on the free end thereof—with second cutting edges  22   a ,  22   b.    
     The second cutting edges  22   a ,  22   b , lie on the same first plane parallel to the plane P, thus the cutting tool  20  is a horizontal cutting tool. Joining the plurality of the second cutting edges  22   a ,  22   b  allows to obtain a second substantially circumference arc-shaped curved line, whose centre is located outside the knife  100  on a second axis substantially orthogonal to the plane P. The second curve defined by the plurality of second cutting edges  22   a ,  22   b  lies on a second plane parallel to the plane P at a second height different from the first height on the vertical axis Z. The second cutting tool  20  is arranged to contribute to the formation of braces  74   a ,  74   b  on the side wall  70  of the capsule, together with the first cutting tool  10  and the third cutting tool  30 . The second cavities  23  are spaced apart and suitably dimensioned so as not to interrupt the continuity of the material, for example so as not to locally alter or to incise but not perforating the side wall  70  of the capsule, so as to allow to form the bridges  73 . 
     With reference to  FIGS.  1 ,  2  and  5   , the third cutting tool  30  has a plate-like structure, parallel to the plane P, and in particular a rectangular base. The third cutting tool  30  has two flat faces, substantially parallel to each other, i.e. the third lower face  37  and the third upper face  38 . 
     The third cutting tool  30  is arranged to perform oblique cuts on the side wall  70 . In a peripheral region  36  thereof, the third cutting tool  30  comprises one or more third tilted blades  31   a ,  31   b ,  31   c ,  33  provided with respective tilted cutting edges  32   a ,  32   b ,  32   c ,  34 . At least two tilted cutting edges  32   a ,  34  have a different tilt from each other, with reference to a reference plane passing through the vertical axis Z and tangent to the advancement direction T. 
     In particular, the tilted cutting edge  32   a  has a negative tilt and the tilted cutting edge  34  has a positive tilt. The negative tilt corresponds to a cutting edge having an upper end thereof receded with respect to a lower end thereof along said advancement direction T and, vice versa, said positive tilt corresponds to a cutting edge having an upper end thereof which is advanced with respect to a lower end thereof along said advancement direction T. As a matter of fact, the tilted cutting edge  32   a  comprises an upper end  92  thereof and a lower end  91  thereof and—considering the advancement direction T—the upper end  92  is receded with respect to the lower end  91 , thus the tilted cutting edge  32   a  with negative tilt. Similarly, the tilted cutting edge  34  comprises an upper end  94  thereof and a lower end  93  thereof and—considering the advancement direction T—the upper end  94  is more advanced with respect to the lower end  93 , thus the tilted cutting edge  34  has a positive tilt. 
     Besides the at least two tilted cutting edges with different mutual tilt  32   a ,  34 , the third cutting tool  30  comprises further third blades with negative tilt  31   b ,  31   c , provided on the respective free end of tilted cutting edges with negative tilt and it may comprise one or more third vertical blades (not shown) with respective vertical cutting edges. 
     Thus, with respect to the cartesian plane formed by the vertical axis Z orthogonal to the plane P and by an axis oriented substantially as the advancement direction T, starting from any point of the advancement direction T, the tilted cutting edges of the third tilted blades may be oriented on the peripheral region  36  in the following alternative fashions:
         with a negative tilt, such as for example the third blades with negative tilt  31   a ,  31   b ,  31   c;      with a positive tilt, such as for example the third blade with positive tilt  33 ;   vertically (not shown), i.e. parallel to the axis Z.       

     The peripheral region  36  of the third cutting tool  30  defines a third substantially circumference arc-shaped curve lying in a third plane, the centre of the circumference is located outside the knife  100  on a third axis substantially orthogonal to the plane P. The peripheral region  36  further defines the surface of the third cutting tool  30  against which the side wall  70  of the capsule  7  can be rotated on the rotation axis R thereof while the knife  100  performs incisions and cuts on the side wall  70 . In other words, the third curvature defined by the peripheral region  36  contributes to guide the capsule  7  along the path thereof for interaction with the knife  100  in the advancement direction T. 
     The third blades with negative tilt  31   a ,  31   b ,  31   c  and the third blades with positive tilt  33  may include cavities (not shown) spaced apart and suitably dimensioned so as not to interrupt the continuity of the material, for example so as not to alter locally or for incising but not perforating the side wall  70  of the capsule, so as to allow to form the bridges  73 . 
     With reference to  FIG.  5   , bridges made of plastic material may be formed on the capsule  7  at the cavities  35  defined by respective lower ends and/or respective upper ends of the tilted cutting edges, such ends being arranged at a predefined distance, in particular considerably small. For example, considering the pair of tilted cutting edges  32   a ,  34  the respective lower ends  91  and  93  are at a limited distance and form a cavity  35  which faints—on the capsule  7 —with the action of the knife  100  a corresponding bridge  75  ( FIGS.  7 A,  7 B ), which will be broken similarly to the bridges  73  when passing from the closing configuration C to the opening configuration D of the capsule  7 . A similar bridge is formed during the cut between the upper end  94  of the cutting edge with positive tilt  34  and the respective upper end of the cutting edge with negative tilt  32   b.    
     The third tilted blade  31   a  extends below the third lower face  37  of the third cutting tool  30  and it is supported by a support protrusion  39   a , which projects from the third lower face  37  below it. In a version not shown, the third tilted blade  31   a  may be laterally contained in the thickness of the third cutting tool  30 , i.e. the lower end thereof does not protrude from the third lower face  37 . In this version, the support protrusion  39   a  may not be present. 
     The third tilted blade  31   b  extends below the third lower face  37  of the third cutting tool  30  and it is also supported by a further support protrusion  39   b  which projects from the third lower face  37  below it. The further support protrusion  39   b  may be obtained in the support protrusion  39   a . In a version, not shown, the third tilted blade  31   b  may be entirely contained in the thickness of the third cutting tool  30 , i.e. the lower end thereof does not protrude from the third lower face  37 . In this version, the support protrusion  39   b  may not be present. 
     Each support protrusion  39   a ,  39   b  is shaped so as to be received in a recess present on the first cutting tool  10 . In particular, the support protrusions  39   a ,  39   b  are both received in the recess  16   a  of the first cutting tool  10 . 
     The third cutting tool  30  is arranged to form oblique cuts  79  on the side wall  70  of the capsule  7 , where oblique cuts also include vertical cuts. 
     Still with reference to  FIGS.  1 - 5   , an assembly configuration of the knife  100  provides for the interposition of the third cutting tool  30  between the first cutting tool  10  and the second cutting tool  20 , as described hereinafter. 
     In such assembly configuration of the knife  100 :
         the second lower face  24  is at contact with the third upper face  38 ;   the third lower face  37  is at contact with the first upper face  15 .       

     Furthermore, in such assembly configuration of the knife  100 :
         the first axis of the first curvature defined by the first cutting edges  12   a ,  12   b ,  12   c  of the first cutting tool  10 ;   the second axis of the second curvature defined by the second cutting edges  21   a ,  21   b  of the second cutting tool  20 ; and   the third axis of the third curvature defined by the peripheral region  36  of the third cutting tool  30  are substantially coincident with each other.       

     Furthermore, in such assembly configuration of the knife  100 , the relative position between:
         the first blades  11   a ,  11   b ,  11   c;      the second blades  21   a ,  21   b;      the third blades with negative tilt  31   a ,  31   b ,  31   c;      the third blades with positive tilt  33 ; and   possible third vertical blades;
 
defines an arrangement of cutting edges  60  of the knife  100 .
       

     Now, with reference to  FIG.  6   , the arrangement of cutting edges  60  of the knife  100  is defined by:
         the first cutting edges  12   a ,  12   b ,  12   c  lying on a first plane parallel to the plane P;   the second cutting edges  22   a ,  22   b  lying on the second plane parallel to the plane P;   the third cutting edges with negative tilt  32   a ,  32   b ,  32   c  and the third cutting edges with positive tilt  34  arranged in an oblique fashion with respect to the plane P.
 
The arrangement of cutting edges  60  may comprise possible third vertical cutting edges orthogonal to the plane P.
       

     As already mentioned above, the first cutting edges  12   a ,  12   b ,  12   c  and the second cutting edges  22   a ,  22   b  are arranged with respect to each other at different heights along the vertical axis Z, i.e. at different distances from the plane P. 
     With reference to  FIGS.  7 A and  7 B , depending on the relative position between the cutting edges of the cutting tools, the knife  100  forms—on the side wall  70  of the capsule  7 —different components:
         one or more intended detachment lines  78   a ,  78   b ,  78   c  arranged on the same plane and obtained by a penetration of the first cutting edges  12   a ,  12   b ,  12   c  passing through the thickness of the side wall  70 ;   one or more connecting portions, or braces  74   a ,  74   b , each in turn comprising:
           a central portion  77   a ,  77   b , obtained by the through penetration of the first cutting edges  12   a ,  12   b ,  12   c  and of the second cutting edges  22   a ,  22   b ; and   a joint portion  76   a ,  76   b , obtained by the through penetration of the second cutting edges  22   a ,  22   b  and of the third cutting edges with negative tilt  32   a ,  32   b ,  32   c  and of the third cutting edges with positive tilt  34 ;   
           one or more oblique cuts  79 , due to the penetration of the third blades with negative tilt  31   a ,  31   b ,  31   c  and of the third blades with positive tilt  34 .       

     In detail, with reference to  FIG.  6   , following the advancement direction T, the knife  100  comprises:
         an opening forming part  68   a , comprising the first cutting edge  12   a  which lies on the first plane parallel to the plane P. The opening forming part  68   a  extends for example for about 50% of the length of the knife  100 . The relative intended detachment line  78   a  corresponds to the opening forming part  68   a  on the capsule  7  ( FIGS.  7 A,  7 B );   a connection forming part  64   a . The connection forming part  64   a  extends for example for about 10% of the length of the knife  100 . The brace  74   a  corresponds to the connection forming part  64   a  on the capsule  7 . The connection forming part  64   a  in turn comprises:
           a connection forming central part  67   a , wherein the last portion of the first cutting edge  12   a  is superimposed along the vertical axis Z on an initial portion of the second cutting edge  22   a  lying on the second plane, i.e. at a higher height with respect to the first cutting edge  12   a . The connection forming central part  67   a  extends for example for about ⅔ of the connection forming part  64   a . A respective central part of the brace  77   a  corresponds to the connection forming central part  67   a;      a joint forming part  66   a , downstream of the connection forming central part  67   a , in which there is a brief section of the second cutting edge  22   a , whose end of the final portion thereof is at the initial end of a third cutting edge with negative tilt  32   a . In other words, the joint forming part  66   a  comprises the final portion of the second cutting edge  22   a  and the third cutting edge with negative tilt  32   a . The joint forming part  66   a  extends for example for about ⅓ of the connection forming area  64   a . The respective joint portion  76   a  corresponds to the joint forming part  66   a  on the capsule  7 ;   
           a brace forming central part  69 , wherein the final end of the third cutting edge with negative tilt  32   a  ends at a height that can be equal to or lower than that of the plane parallel to the first plane on which the first cutting edge  12   a  lies. The initial end of the third cutting edge with positive tilt  34  is located at the final end of the third cutting edge with negative tilt  32   a . The third cutting edge with positive tilt  34  ends at a height that is equal, but it can be higher, to that of the second plane on which the second cutting edge  22   a  lies. The final upper end of the third cutting edge with positive tilt  34  is at the initial upper end of a third cutting edge with negative tilt  32   b  tilted. The brace forming central part  69  further comprises the third cutting edge with positive tilt  34  and the third cutting edge with negative tilt  32   b . One or more oblique cuts  79  correspond to the brace forming central part  69  on the side wall  70 . The brace forming central part  69  extends for example between 5% and 10% of the length of the knife  100 ;   a further opening forming part  68   b , comprising a first cutting edge  12   b  lying on the first plane. The further opening forming part  68   b  extends for example between 5% and 10% of the length of the knife  100 . The relative intended detachment line  78   b  corresponds to the further opening forming part  68   b;      a further connection forming part  64   b . The further connection forming part  64   b  extends for example for about 10% of the length of the knife  100 . The brace  74   b  corresponds to the further connection forming part  64   b . The further connection forming part  64   b  in turn comprises:
           a further connection forming central part  67   b  wherein the last portion of the first cutting edge  12   b  is superimposed along the vertical axis Z on an initial portion of the second cutting edge  22   b  lying on the second plane, i.e. at a for example higher height with respect to the first cutting edge  12   a . The further connection forming central part  67   b  extends for example for about ⅔ of the further connection forming part  64   b . The respective brace central portion  77   b  corresponds to the further connection forming central part  67   b;      a further joint forming part  66   b , downstream of the further connection forming central part  67   b , in which there is a brief section of the second cutting edge  22   b , whose end of the final portion thereof is at the initial end of a third cutting edge with negative tilt  32   c . In other words, the further joint forming part  66   b  comprises the final portion of the second cutting edge  22   b  and the third cutting edge with negative tilt  32   c . The further joint forming part  66   b  extends for example for about ⅓ of the further connection forming part  64   b . The respective joint portion  76   b  corresponds to the further joint forming part  66   b  on the capsule  7 ;   
           a further opening forming part  68   c , in which—at the final end of the third cutting edge with negative tilt  32   c —there is located a first cutting edge  12   c  lying on the first plane which extends for example for about 20% of the length of the knife  100  along the advancement direction T. The respective intended detachment line  78   c  corresponds to a still further opening forming part  68   c.          

     It should be observed that the arrangement of cutting edges  60 , since it is suitable for cutting an object with substantially cylindrical symmetry, may have a different order of the parts of the arrangement of cutting edges  60  described above provided that succession is complied with; for example the opening forming parts  68   a  and  68   c  of the arrangement of cutting edges  60  may be incorporated in a single opening forming part arranged together as an initial or final part of the arrangement of cutting edges  60  along the advancement direction T. 
     In the context of the invention, the terms “initial/final”, “starts/ends” and “start/end”, “upstream/downstream” are used to indicate the order in which the projections of the ends of the cutting edges along the advancement direction T are found. 
     The layered structure of the knife and the relative assembly configuration allow to change the arrangement of cutting edges to be incised on the capsules by adding and/or replacing cutting tools in the assembly configuration. In particular, given that the horizontal cuts may be maintained for a given dimension of the capsule, the third cutting tool can be replaced to produce—on a capsule of the same dimension—a different shape of the braces, without having to replace the first cutting tool and the second cutting tool too. This is allowed by the fact that the shape of the braces is substantially determined by the cutting edges with different tilt that are provided for in the third cutting tool. 
     In the second illustrated embodiment, the knife  100 ′, comprises additional cutting tools arranged to incise the side surface  70  of the capsules  7 , i.e. a fourth cutting tool  40  and a fifth cutting tool  50 . In the embodiment of the knife  100 ′ there are also present the first cutting tool  10  and the second cutting tool  20 , while the cutting tool  30 ′ has the same number of blades as the version according to  FIGS.  1 - 6    with a different arrangement, as described hereinafter. The fourth cutting tool  40 , the first cutting tool  10 , the third cutting tool  30 ′, the second cutting tool  20  and the fifth cutting tool  50  are stacked on each other, in a removable assembly. The knife  100 ′ is removably fixed to the frame of the cutting apparatus by fastening means, not shown, such as for example screw means or bolt means, which furthermore allow the cutting tools  10 ,  20 ,  30 ′,  40 ,  50  to be clamped and removably fixed to each other. With reference to  FIG.  10   , each of the cutting tools  10 ,  20 ,  30 ′,  40 ,  50  comprises, in particular, at least one hole  91 ′,  92 ′ of the through type, arranged to receive the fastening means, so that said cutting tools  10 ,  20 ,  30 ′,  40 ,  50  can be removed or inserted from/into the layered structure, according to the stacking order from top to bottom tool. With reference to  FIG.  10 A , the at least one hole  91 ′,  92 ′ can comprise, in particular, at least one eccentric hole, or slot  92 ′, arranged for allowing a position adjustment of the cutting tools  10 ,  20 ,  30 ′ independently from each other, in particular on a plane parallel to the plane P. The at least one hole  91 ′,  92  enables, in particular, the selective removal of each cutting tool  10 ,  20 ,  30 ′ to allow the removal and/or insertion of additional cutting tools, for example, to replace a tool with worn cutting edges or to change the arrangement of the cutting edges. For example, it is possible to replace only the third cutting tool  30 ′, restoring the layered structure without replacing the other cutting tools. 
     With reference to  FIG.  12   , the fourth cutting tool  40  has a plate-like structure, parallel to the plane P, and in particular a rectangular base. The fourth cutting tool  40  has two flat faces, substantially parallel to each other, i.e. the fourth lower face  44  and the fourth upper face  45 . 
     The fourth cutting tool  40 , on a fourth peripheral region  47 , comprises a fourth blade  41 . The fourth blade  41  is provided—on a free end thereof—with a fourth cutting edge  42 . The fourth cutting edge  42 , or at least one point thereof, is located on a fourth substantially circumference arc-shaped curvature, whose centre is located outside the knife  100 ′ on a fourth axis substantially orthogonal to the plane P. The fourth curvature, and thus the fourth cutting edge  42 , lies on a fourth plane at a height lower than the first cutting edge  12   a . The fourth cutting edge  42  has a longitudinal extension smaller than the circumference of the side wall  70  of the capsules to be processed. The fourth cutting tool  40  is arranged to form an accessory groove  75 ′ ( FIGS.  9 A and  9 B ) on the side wall  70  of the capsules. The fourth cutting tool  40  cooperates with the fifth cutting tool  50  and the third cutting tool  30 ′ to form the braces  74   a ,  74   b . The fourth blade  41  may include one or more fourth cavities  43  spaced apart and suitably dimensioned so as not to interrupt the continuity of the material, for example so as not to alter locally or for incising but not perforating the side wall  70  of the capsule, so as to allow to form the bridges  73 . In particular, the fourth cutting edge  42  comprises only one cavity  43 . 
     Still with reference to  FIG.  12   , the fifth cutting tool  50  has a plate-like structure, parallel to the plane P, and in particular a rectangular base. The fifth cutting tool  50  has two flat faces, substantially parallel to each other and to the plane P, i.e. the fifth lower face  55  and the fifth upper face  55 . 
     The fifth cutting tool  50 , on a fifth peripheral region  57 , comprises a fifth blade  51 . The fifth blade  51  is provided—on a free end thereof—with a fifth cutting edge  52 . The fifth cutting edge  52 , or at least one point thereof, is located on a fifth substantially circumference arc-shaped curvature, whose centre is located outside the knife  100 ′ on a fifth axis substantially orthogonal to the plane P. The fifth curvature lies on a fifth plane. The fifth cutting edge  52  has an extension smaller than the circumference of the side wall  70  of the capsules to be processed. The fifth cutting tool  50  is arranged to form a further accessory groove  79 ′ ( FIGS.  9 A and  9 B ) on the side wall  70  of the capsules. The fifth cutting tool  50  cooperates with the fourth cutting tool  40  and the third cutting tool  30 ′ to form the braces  74   a ,  74   b.    
     The fifth blade  51  includes one or more fifth cavities  53  spaced apart and suitably dimensioned so as not to interrupt the continuity of the material, for example so as not to alter locally or for incising but not perforating the side wall  70  of the capsule, so as to allow to form the bridges  73 . In particular, the fifth cutting edge  51  comprises only one cavity  53 . 
     With reference to  FIG.  13   , the further third cutting tool  30 ′ has a structure similar to that of the third cutting tool  30  described previously, which will not be repeated for the sake of brevity. Thus, the parts similar—in terms of shape and function—are indicated with the same reference numerals in the drawings. The difference between the further third cutting tool  30 ′ and the third cutting tool  30  is in the arrangement of further third blades with negative tilt  31   a ′,  31   b ′ and of a further third blade with positive tilt  33 ′. As a matter of fact, as will be described in detail hereinafter, the end of third cutting edges with negative tilt  32   a ′,  32   b ′ and end of third cutting edges with positive tilt  34 ′ may be spaced apart by an amount approximately equal to that of the extension along the advancement direction T of the fourth cutting edges  42  and/or of the fifth cutting edges  52 . 
     The third cutting tool  30 ′ is arranged to perform oblique cuts on the side wall  70 . In a peripheral region  36 ′ thereof, the third cutting tool  30  comprises one or more third tilted blades  31   a ′,  31   b ′,  31   c ′,  33 ′ provided with respective tilted cutting edges  32   a ′,  32   b ′,  32   c ′,  34 ′. At least two tilted cutting edges  32   a ′,  34 ′ have an tilt different from each other, with reference to a reference plane passing through the vertical axis Z and tangent to the advancement direction T. 
     In particular, the tilted cutting edge  32   a ′ has a negative tilt and the tilted cutting edge  34 ′ has a positive tilt. The negative tilt corresponds to a cutting edge having an upper end thereof receded with respect to a lower end thereof along said advancement direction T and, vice versa, said positive tilt corresponds to a cutting edge having an upper end thereof which is advanced with respect to a lower end thereof along said advancement direction T. As a matter of fact, the tilted cutting edge  32   a ′ comprises an upper end  92 ′ thereof and a lower end  91 ′ thereof and—considering the advancement direction T—the upper end  92 ′ is receded with respect to the lower end  91 ′, thus the tilted cutting edge  32   a ′ has negative tilt. Similarly, the tilted cutting edge  34 ′ comprises an upper end  94  thereof and a lower end  93  thereof and—considering the advancement direction T—the upper end  94 ′ is more advanced with respect to the lower end  93 ′, thus the tilted cutting edge  34 ′ has a positive tilt. 
     Similarly to the tilted cutting edge  32   a , the tilted cutting edge  32   a ′ extends below the height of the third lower face  37 ′ and it is supported by a support protrusion  39   a ′. Even the tilted cutting edge  34 ′ extends below the height of the third lower face  37 ′ and it is supported by a further support protrusion  39   b ′. Furthermore, the tilted cutting edge  34 ′ extends even above the height of the third upper face  38 ′, supported by a support protuberance  39   c ′ which projects from the third upper face  38 ′ superimposed thereto. 
     The fifth blade  51  thus rests on the support protuberance  39   c ′, as shown in  FIG.  11   . The support protuberance  39   c ′ can be received in one or more second recesses  26  of the second cutting tool  20 . The third tilted cutting edge  32   b ′ is obtained on the respective tilted blade  31   b ′, that extends above the third upper face  38 ′ and it is supported by a respective projection, that projects from the third upper face  38 ′ above said third upper face  38 ′. The projection can be obtained in the support protuberance  39   c ′, for example it can be a sole body with the support protuberance  39   c′.    
     The aforementioned projections and protrusions are housed in the recesses of the first and second cutting tool similar to those provided for in the version of the knife  100 . 
     With reference to  FIGS.  10  and  11   , an assembly configuration of the knife  100 ′ provides for the interposition of the third cutting tool  30 ′ between the first cutting tool  10  and the second cutting tool  20 , and between the fourth cutting tool  40  and the fifth cutting tool  50  as described hereinafter. 
     In such assembly configuration of the knife  100 ′:
         the fifth lower face  54  is at contact with the second upper face  25 ;   the second lower face  24  is at contact with the third upper face  38 ′;   the third lower face  37 ′ is at contact with the first upper face  15 ;   the first lower face  14  is at contact with the fourth upper face  45 .       

     Furthermore, in such assembly configuration of the knife  100 ′:
         the first axis of the first curvature defined by the first cutting edges  12   a ,  12   b ,  12   c  of the first cutting tool  10 ,   the second axis of the first curvature defined by the second cutting edges  21   a ,  21   b  of the second cutting tool  20 ,   the third axis of the third curvature defined by the peripheral region  36 ′ of the third cutting tool  30 ′,   the fourth axis of the fourth curvature on which at least one point of the fourth cutting edge  42  is located, and   the fifth axis of the fifth curvature on which at least one point of the fifth cutting edge  52  is located,
 
are substantially coincident with each other.
       

     Furthermore, in this assembly configuration the knife  100 ′, the relative position between: the first blades  11   a ,  11   b ,  11   c , the second blades  21   a ,  21   b , the third blades with negative tilt  31   a ′,  31   b ′,  31   c ′, the third blades with positive tilt  33 ′ and possible third orthogonal blades define an arrangement of cutting edges  60 ′ of the knife  100 ′. 
     With reference to  FIG.  8   , the arrangement of cutting edges  60 ′ of the knife  100 ′ is defined by:
         the first cutting edges  12   a ,  12   b ,  12   c  lying on a first plane parallel to the plane P;   the second cutting edges  22   a ,  22   b  lying on the second plane parallel to the first plane;   the further third cutting edges with negative tilt  32   a ′,  32   b ′,  32   c ′ and the third cutting edge with positive tilt  34 ′ arranged in an oblique fashion with respect to the plane P and/or possible third cutting edges orthogonal to the plane P;   the fourth cutting edge  42  lying on the fourth plane parallel to the plane P;   the fifth cutting edge  52  lying on the fifth plane parallel to the plane P.       

     The ends of the third cutting edges with negative tilt  32   a ′,  32   b ′,  32   c ′ and the ends of the third cutting edges with positive tilt  34 ′ are positioned close to or at contact with the ends of other cutting edges, as for example in proximity of or at contact with the ends of the cutting edges  12   a ,  12   b ,  12   c  and/or the ends of the cutting edges  22   a ,  22   b  and/or the ends of the third cutting edges with negative tilt  32   a ′,  32   b ′,  32   c ′, and the ends of the third cutting edges with positive tilt  34 ′ and/or the ends of the fourth cutting edge  42  and/or the ends of the fifth cutting edge  52 . In the event that the end of the cutting edges with negative tilt  32   a ′,  32   b ′ and the ends of the third cutting edges with positive tilt  34 ′ be positioned in proximity of the other ends of the cutting edges there are identified third cavities spaced apart and suitably dimensioned so as not to interrupt the continuity of the material, for example so as not to alter or for incising but not perforating the side wall  70  of the capsule, so as to allow to form the bridges. 
     With reference to  FIGS.  9 A and  9 B , depending on the relative position between the cutting edges of the cutting tools, the knife  100 ′ forms—on the side wall  70  of the capsule  7 —an arrangement of oblique cuts  79 ′ which may be different from the one illustrated, which is obtained by the penetration of the third blades with negative tilt  31   a ′,  31   b ′ and of the third blades with positive tilt  33 ′, of the fourth blade  41  and of the fifth blade  51 . 
     In detail, with reference to  FIGS.  8 ,  9 A,  9 B and  10   , following the path along the advancement direction T, the knife  100 ′ comprises:
         an accessory central part  69 ′. The accessory central part  69 ′ comprises the fourth cutting edge  42 , the third cutting edge with positive tilt  34 ′, the fifth cutting edge  52  and the third cutting edge with negative tilt  32   b ′, in which the final end of the third cutting edge with negative tilt  32   a ′ ends at a height which may be equal to or lower than that of the plane parallel to the first plane P on which the first cutting edge  12   a  lies. The initial end of the fourth cutting edge  42  lying on the fourth plane, i.e. at a height lower than that of plane P is located at the final end of the third cutting edge with negative tilt  32   a ′. The final end of the fourth cutting edge  42  is located at, or at contact with, the initial end of the third cutting edge with a positive tilt  34 ′ tilted or in a vertical arrangement. The third cutting edge with positive tilt  34 ′ ends at a height that can be equal to or higher than that of the second plane on which the second cutting edge  22   a  lies. The final end of the third cutting edge with positive tilt  34 ′ is close to or at contact with the initial end of the fifth cutting edge  52  lying on the fifth plane, i.e. at a height which may be higher than that of the second plane on which the second cutting edge  22   a  lies. The final end of the fifth cutting edge  52  is located at a third cutting edge with negative tilt  32   b ′. The accessory central part  69 ′ corresponds to a plurality of oblique cuts and flat cuts, in which a flat cut is interposed between two oblique cuts of different tilt on the side wall  70 ; the plurality of oblique cuts and flat cuts allows to separate the two braces  74   a ,  74   b  from each other. The accessory central part  69 ′ extends for example between 5% and 10% of the length of the knife  100 ′.       

     Owing to the shape of the knife  100 ,  100 ′ it is possible to disassemble the third cutting tool  30 ;  30 ′ from the layered structure and replace it with a different third cutting tool to obtain a different shape of the connecting portions or braces  74   a ,  74   b . This simplifies the cutting apparatus and reduces the machine downtimes to equip the cutting apparatus with a different knife. Furthermore, the cutting apparatus also maintains a certain flexibility, given that it is possible to perform cuts with a knife in which a small number of cutting tools is to be replaced in order to change the geometry of the cut on the capsule. 
     The illustrated examples show a grooved capsule with two braces, both tilted with a negative tilt with respect to the advancement direction T, as can be seen in the open configuration D of the capsule. It is clear that a man skilled in the art would have no difficulty in modifying the number and arrangement of the cutting edges of the knife  100 ,  100 ′ for cutting capsules with a number of braces greater than two, for example three or four braces, tilted with negative and/or positive tilts according to various combinations. 
     It is possible to provide for a number and arrangement of the cutting edges, having positive and negative tilts combined to form three tilted braces arranged with the same tilt or a brace with a certain tilt and two consecutive braces with the opposite tilt or three braces with alternating tilts. It is also possible to provide for another different arrangement of the cutting edges, whose combination of positive and negative tilts may form four braces arranged tilted all with the same tilt or in groups of two braces with opposite tilt, or four braces tilted with alternating tilts or three consecutive braces tilted with the same tilt and a brace tilted with the opposite tilt. 
     In order to obtain three or four connecting portions—or braces—which connect the tamper ring  72  and the side wall  70 , besides the two tilted cutting edges  32   a ,  34 ,  32   a ′,  34 ′ in the third cutting tool  30 ,  30 ′ further cutting edges arranged so as to determine—in use—the three connecting portions or the four connecting portions may be provided for. 
     Alternatively or additionally to the further cutting edges in the third cutting tool  30 ,  30 ′, to obtain three connecting portions or four connecting portions, the knife  100 ,  100 ′ may include—in the plurality of cutting tools of the structure thereof—further cutting tools arranged to cooperate with the first horizontal cutting tool  10 , the second horizontal cutting tool  20  and the third cutting tool  30 ,  30 ′ and, if present, with the additional cutting edges to determine—in use—the three connecting portions or the four connecting portions connecting the tamper ring  72  and the side wall  70 .