Method and unit for closing the ends of tubular wrappings on a cigarette packing machine

Information

  • Patent Grant
  • 6601369
  • Patent Number
    6,601,369
  • Date Filed
    Monday, May 7, 2001
    23 years ago
  • Date Issued
    Tuesday, August 5, 2003
    21 years ago
Abstract
A method and unit for closing the ends of tubular wrappings on a cigarette packing machine, wherein the tubular wrappings enclosing respective groups of cigarettes are fed continuously and successively along an annular path and through two folding stations, in the first of which a movable folding member and a fixed folding member, common to all the tubular wrappings, fold the short sides of a projecting tubular portion of the tubular wrapping to define two projecting major tabs, and in the second of which a single rocker arm, common to all the tubular wrappings, is swung to successively fold the two major tabs while the wall of the tubular wrapping coplanar with each major tab is maintained, during folding, contacting a respective flat supporting wall.
Description




The present invention relates to a method of closing the ends of tubular wrappings on a cigarette packing machine.




In particular, the present invention relates to a method of closing the ends of tubular wrappings on a continuously operating cigarette packing machine. In the following description, reference is made solely to closing the ends of inner wrappings of so-called “rigid” packets of cigarettes, though, as will be clear to an average technician in this particular field, the same also applies equally to closing the ends of outer wrappings of so-called “soft” packs.




BACKGROUND OF THE INVENTION




On continuously operating cigarette packing machines, groups of cigarettes are fed successively to respective conveying heads on a wrapping wheel unit, to which each group is supplied already partly wrapped in a respective sheet of wrapping material, normally foil, folded into a U about the group. As it is fed forward on the wrapping unit, each sheet of wrapping material is folded longitudinally at a folding station to form about the respective group a tubular wrapping having two end portions, each projecting from a respective end of the group, and each of which is later folded, at further folding stations, to close the end of the relative tubular wrapping.




On the wrapping unit wheels of known continuously operating packing machines, the tubular wrappings, as they are fed through the folding stations by the respective conveying heads, are normally maintained contacting the conveying heads by means of a cylindrical outer plate, which slides along, and so outwardly curves, an outer wall of each tubular wrapping. At relatively high production speeds, the fact that one of the walls on the tubular wrapping is curved may result, when closing the ends of the tubular wrapping, in improper folding of the end portions, thus resulting in the group being rejected.




U.S. Pat. No. 3,810,314 discloses a packing machine, wherein tubular wrappings are fed successively along a straight folding path and through two folding stations, in the first of which the short sides of a projecting tubular portion of each tubular wrapping are folded to define two projecting major tabs, and in the second of which the two major tabs are folded one towards the other. The straight folding path is defined by lateral fixed folding means and by upper and lower fixed supporting means, which contact the major walls of each tubular wrapping when such tubular wrapping is fed along the straight folding path.




However, the packing machine disclosed by U.S. Pat. No. 3,810,314 can be used only at relatively low production speeds, because when each tubular wrapping is fed along the straight folding path, the relevant major walls creep along the upper and lower fixed supporting means.




SUMMARY OF THE INVENTION




It is an object of the present invention to provide a method of closing the ends of tubular wrappings designed to eliminate the aforementioned drawback, and which is also straightforward and cheap to implement.




According to the present invention, there is provided a method of closing the ends of tubular wrappings enclosing respective groups of cigarettes.




In the method defined above, said two tabs are preferably folded as the relative said tubular wrapping is fed along a path parallel to said major walls; both said tabs being folded successively by means of a single rocker arm mounted to swing about a hinge axis crosswise to said path and comprising two arms located on opposite sides of said hinge axis and each having a respective folding edge for a respective said tab; said rocker arm being swung about said hinge axis so that each said folding edge interferes with said path in time with said tubular wrappings traveling along the path.




Using a rocker arm as described above in itself provides for solving another important problem encountered on most known continuously operating wrapping wheels, and which is the highly complicated mechanical design, and therefore relatively poor reliability and high manufacturing and maintenance cost, of such wheels. Known continuously operating wrapping wheels, in fact, normally feature an outer folding device common to all the conveying heads and for folding one of the major tabs of each end portion of each tubular wrapping, and a number of inner folding devices, each fitted to and movable with respect to a respective conveying head. As a result, the wrapping wheel must be fitted with mechanisms for controlling the inner folding devices, and which, being normally both complicated and bulky, further complicate the already complex structure of the wrapping wheels.




Using a rocker arm as described above, on the other hand, provides for eliminating all the inner folding devices, and for folding both the major tabs of each end portion of each tubular wrapping using one outer folding member.




The present invention also relates to a unit for closing the ends of tubular wrappings.




According to the present invention, there is provided a unit for closing the ends of tubular wrappings enclosing respective groups of cigarettes.











BRIEF DESCRIPTION OF THE DRAWINGS




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





FIGS. 1

to


5


show schematic lateral elevations, with parts removed for clarity, of a preferred embodiment of the wrapping unit according to the present invention in different operating positions;





FIG. 6

shows an enlarged section along line VI—VI in

FIG. 2

;





FIG. 7

shows an enlarged section along line VII—VII in

FIG. 2

;





FIGS. 8



a


,


8




b


,


8




c


, and


8




d


show enlarged partial isometric views of a succession of folding steps performed on the wrapping unit in

FIGS. 1

to


5


.











DETAILED DESCRIPTION OF THE INVENTION




With reference to one of

FIGS. 1

to


5


, number


1


indicates as a whole a continuously operating cigarette packing machine comprising a wrapping unit


2


for successively receiving groups


3


of cigarettes, each enclosed in a respective sheet


4


of wrapping material folded about group


3


to define a tubular wrapping


5


. As shown more clearly in

FIG. 8



a,


each tubular wrapping


5


comprises two major walls


6


, two minor walls


7


perpendicular to major walls


6


, and at least one substantially rectangular-section tubular end portion


8


.




When, as in the example shown, sheet


4


of wrapping material is a sheet of foil directly contacting the cigarettes in the relative group


3


, there are two opposite tubular portions


8


; whereas, when sheet


4


of wrapping material is used to form the outer wrapping of a soft pack (not shown), there may be only one tubular portion


8


.




Tubular end portion


8


projects axially with respect to relative group


3


, and comprises two short sides


9


coplanar with respective minor walls


7


, and two long sides


10


coplanar with respective major walls


6


.




Wrapping unit


2


comprises a wrapping wheel


11


mounted to rotate about a respective axis


12


(

FIG. 1

) and rotated at substantially constant angular speed about axis


12


by a motor


13


. Wrapping wheel


11


comprises a number of known conveying heads


14


equally spaced about, and each positioned radially with respect to, axis


12


. Each conveying head


14


is fitted to wrapping wheel


11


so as to swing, with respect to wrapping wheel


11


, about a respective intermediate axis


15


parallel to axis


12


, and comprises a flat end plate


16


defining a supporting surface for a relative group


3


of cigarettes enclosed in relative tubular wrapping


5


.




Each conveying head


14


supports relative tubular wrapping


5


with minor walls


7


positioned substantially radially with respect to axis


12


, with one of major walls


6


contacting plate


16


and the other facing outwards, and with the longitudinal axis of the tubular wrapping parallel to axis


12


.




Each head


14


feeds relative group


3


and relative sheet


4


of wrapping material in a direction


17


(clockwise in

FIGS. 1

to


5


) along an annular path P extending about axis


12


and at least partly along a channel


18


defined internally by plates


16


and externally by a cylindrical plate


19


coaxial with axis


12


and which slides against an intermediate portion of the outer wall


6


of each tubular wrapping


5


.




For the sake of simplicity, the following description refers to a packing machine


1


on which each tubular wrapping


5


has only one tubular portion


8


, it being understood that, in the case of two portions


8


, the folding devices described must be duplicated and share the relative actuating devices.




Wrapping unit


2


comprises a folding device


20


located at a folding station


21


to fold the short sides


9


of each tubular wrapping


5


onto the relative group


3


and define on the relative long sides


10


two tabs


22


coplanar wish respective major walls


6


; and a further folding device


23


located at a further folding station


24


, downstream from folding station


21


in direction


17


, to fold tabs


22


successively onto relative group


3


and one towards the other to close the end of relative tubular wrapping


5


completely and obtain a wrapping


25


fully enclosing relative group


3


.




As shown in any one of

FIGS. 1

to


5


, folding device


20


is located substantially outwards of path P, i.e. on the opposite side of path P to wrapping wheel


11


, and comprises a motor


26


, which is fitted to a frame (not shown) of packing machine


1


, has a fixed axis of rotation


27


parallel to axis


12


, and has an output shaft


28


coaxial with axis


27


and fitted with a crank


29


The free end of crank


29


is fitted with a pin


30


parallel to axis


12


and in turn fitted with a rod


31


, which is shorter than crank


29


, is superimposed on crank


29


, substantially extends towards axis


27


, and is fitted on the free end with a pin


32


parallel to axis


12


and defining, with shaft


28


, a virtual crank


33


of a length equal to the distance between axis


27


and the axis of pin


32


.




Pin


32


is connected in rotary manner to a first arm


34


of a rocker arm


35


, a second arm


36


of which is curved and fitted on the free end with a movable folding member


37


facing substantially in direction


17


and of a width approximately equal to but no greater than the width of shirt sides


9


of tubular portion


8


. Between arms


34


and


36


, rocker arm


35


is fitted with a pin


38


parallel to axis


12


and connected in rotary manner to the free end of a further crank


39


, the other end of which is connected to said frame (not shown) to rotate about a fixed axis


40


parallel to axis


12


.




Virtual crank


33


, arm


34


of rocker arm


35


, and crank


39


define an articulated parallelogram


41


, which is activated to impart to folding member


37


an active stroke—from a withdrawn rest position (

FIG. 3

) outwards of path P, to a forward work position (FIG.


5


)—along a trajectory which extends in a plane tangent to the relative end of groups


3


, is traveled at a speed slightly faster than the traveling speed of conveying heads


14


, and comprises an end portion extending along path P and in direction


17


.




Folding device


20


also comprises a fixed folding member


42


, which is the same width as movable folding member


37


, is located along path P in a plane tangent to the relative end of groups


3


, and is so positioned that the rear end, in direction


17


, substantially contacts movable folding member


37


when movable folding member


37


is in the forward work position (FIG.


5


). A relatively thin appendix


43


extends from the front end of fixed folding member


42


, and is substantially parallel to direction


17


and tangent to the path traveled by the outer surface of flat end plate


16


of each conveying head


14


.




Appendix


43


faces an opening


44


formed through plate


19


to permit the passage of an arm


45


of a rocker


46


forming part of folding device


23


Rocker arm


46


is hinged to a fixed central pin


47


fitted to a plate


48


integral with plate


19


and located downstream from opening


44


in direction


17


. Rocker arm


46


rotates about a fixed axis


49


parallel to axis


12


, and comprises a further arm


50


extending to the side of plate


19


and to the side of and through path P. Arm


45


is movable through opening


44


and in a plane substantially tangent to the relative end of groups


3


, and comprises, on the side facing axis


12


, a folding edge


51


for successively engaging and folding the outer tab


22


of each tubular wrapping


5


onto the relative end of groups


3


. As shown more clearly in

FIG. 7

, the surface of arm


50


facing conveying heads


14


has a longitudinal rib


52


, which extends along an edge of arm


50


facing axis


12


, has an end surface


53


movable along a plane tangent to the relative end of relative group


3


, and is defined outwards, i.e. on the opposite side to axis


12


, by a flat surface transverse to surface


53


and defining a folding edge


54


for successively engaging and folding the inner tab


22


(i.e. the one coplanar with flat plate


16


of relative conveying head


14


) of each tubular wrapping


5


onto the relative end of relative group


3


and into a position overlapping relative outer tab


22


.




The two folding edges


51


and


54


are separated by a distance, measured along path P, equal to the distance between two corresponding points on plates


16


of two adjacent conveying heads


14


, so that, when folding edge


51


acts on one tubular wrapping


5


—hereinafter referred to as


5




a


—carried by one conveying head


14


—hereinafter referred to as


14




a


—folding edge


54


acts on a tubular wrapping


5




b


carried by a conveying head


14




b


immediately downstream from conveying head


14




a


in direction


17


.




Rocker arm


46


performs about axis


49


a swing whose active stroke moves folding edges


51


and


54


from a noninterference rest position (FIG.


1


)—in which neither of edges


51


and


54


interferes with path P, and edge


51


is located outwards of, and edge


54


inwards of, path P—to at interference work position (FIG.


4


)—in which edges


51


and


54


are substantially aligned along path P, edge


51


maintains folded an outer tab


22


of a tubular wrapping


5




a


carried by a conveying head


14




a,


and edge


54


maintains forded an inner tab


22


of a tubular wrapping


5




b


carried by a conveying head


14




b.






Rocker arm


46


is swung between said work and rest positions by a crank


55


, which is integral with rocker arm


46


, rotates with rocker arm


46


about axis


49


, and forms part of an articulated parallelogram


56


, which in turn forms part of folding device


23


, is activated by motor


26


, and, in addition to crank


55


, comprises crank


29


, and a connecting rod


57


connected in rotary manner at one end to pin


32


and at the other end to a pin


58


parallel to pin


30


and connected integrally to a free end of crank


55


.




Wrapping unit


2


also comprises a pressure device


59


located between folding devices


20


and


23


, substantially at opening


44


, and in turn comprising a flat wall defined by a pad


60


located laterally, in the direction of axis


12


, with respect to plate


19


, and which engages the outer major wall


6


of each tubular wrapping


5


engaging folding station


24


in a position facing folding edge


51


. More specifically, pad


60


engages the portion of outer major wall


6


located between plate


19


and the relative end of relative group


3


, i.e. the portion between plate


19


and the join of the relative outer major tab


22


.




Pad


60


is movable, firstly, from a rest position (

FIG. 4

) in which pad


60


is located outwards of path P, to a work position in which pad


60


is tangent to path P and parallel to plate


16


of a conveying head


14


at the input of folding station


24


, and secondly in such a manner as to remain parallel to said plate


16


and contacting the outer major wall


6


of relative tubular wrapping


5


as wrapping


5


is fed along the portion of folding station


24


extending along arm


45


of rocker arm


46


. These movements—which, at all times, are the resultant of a linear movement of pad


60


in an instantaneous radial direction with respect to axis


12


, anti of rotation of pad


60


about an instantaneous axis parallel to axis


12


—are imparted to pad


60


by an actuating device


61


, which comprises an articulated polygon


62


defined, in addition to pad


60


, by two powered arms


63


and


64


fitted to the frame (not shown) of packing machine


1


to rotate about axis


40


, and of which arm


63


is hinged to one end of pad


60


, while arm


64


is connected to the other end of pad


60


by the interposition of a hinge lever


65


. In the example shown, arms


63


and


64


form part of respective rocker arms


66


and


67


, which are hinged about axis


40


and fitted, at the opposite ends to respective arms


63


and


64


, with respective tappets (not shown) cooperating with respective cams (not shown) on wrapping wheel


11


.




Operation of wrapping unit


2


will now be described with reference to one conveying head


14


as regards folding station


21


and an input portion of folding station


24


, and with reference to two adjacent conveying heads


14




a


and


14




b


as regards an end portion of folding station


24


.




With reference to

FIG. 1

, when the conveying head


14


considered (the one to the right in

FIG. 1

) nears folding station


21


along path P in direction


17


, the relative tubular wrapping


5


is fed, together with relative group


3


, along channel


18


and is maintained contacting relative plate


16


by plate


19


sliding against the intermediate portion of outer major wall


6


of tubular wrapping


5


. At the same time, as shown in

FIGS. 1

,


2


and


3


, movable folding member


37


is moved into the rest position by motor


26


via articulated parallelogram


41


. When the conveying head


14


considered begins to engage folding station


21


(FIG.


4


), movable folding member


37


is reversed from the rest position to the work position; in the course of which movement, movable folding member


37


first reaches and travels along channel


18


so as to engage the rear short side


9


of relative tubular wrapping


5


and fold the short side


9


forward (

FIG. 5

) onto the relative free end of relative group


3


. As soon as the rear short side


9


is folded, and before movable folding member


37


reaches its final position (FIG.


5


), the front short side


9


encounters and is folded by fixed folding member


42


onto the relative end of relative group


3


to define the two tabs


22


. Finally, movable folding member


37


is arrested in the work position substantially contacting fixed folding member


42


to enable the folded rear short side


9


to pass beneath fixed folding member


42


.




At this point, as shown in

FIG. 1

, in which the conveying head


14


considered is now the central conveying head


14


indicated


14




a,


movable folding member


37


withdraws from path P into the rest position, while conveying head


14




a


and relative tubular wrapping


5




a


move into position in front of opening


44


and enter folding station


24


with short sides


9


maintained in the folded position by appendix


43


of fixed folding member


42


. Just before this takes place (FIG.


5


), pad


60


of pressure device


59


is in the rest position, as is rocker arm


46


, the folding edges


51


and


54


of which are located on opposite sides of and outwards of channel


18






As tubular wrapping sa enters folding station


24


(FIG.


1


), i.e. begins moving into position facing folding edge


51


, actuating device


61


moves pad


60


into the work position contacting the outer major wall


6


of tubular wrapping


5




a,


and into a position parallel to the position assumed, at that moment, by plate


16


of conveying head


14




a,


so as to flatten the outer major wall


6


curved outwards by contact with plate


19


. Subsequently, for as long as outer tab


22


of tubular wrapping


5




a


remains facing folding edge


51


(

FIGS. 1

to


3


), pad


60


is moved by actuating device


61


so as to remain contacting outer major wall


6


and parallel to the position assumed at each moment by plate


16


of conveying head


14




a.






At the same time, motor


26


begins moving rocker arm


46


into the work position (

FIG. 1

) so that folding edge


51


engages outer tab


22


of tubular wrapping


5




a


through opening


44


and gradually folds outer tab


22


towards the relative end of group


3


and onto the two already folded short sides


9


. Outer tab


22


is folded completely before tubular wrapping


5




a


leaves appendix


43


and begins leaving opening


44


, and without engaging appendix


43


, which, given its transverse dimensions, remains within the group


3


end space not covered by the folded outer tab


22


. As wrapping


5




a


leaves opening


44


, the folded outer tab


22


is inserted beneath a tooth


68


, which projects inwards from plate


19


, is located downstream from opening


44


, and provides for keeping outer tab


22


folded until the end of tubular wrapping


5




a


is fully closed. At the same time, pad


60


releases tubular wrapping


5




a


and moves into the rest position (FIGS.


4


and


5


).




As the above steps are being performed to fold tab


22


of tubular wrapping


5




a,


a tubular wrapping


5




b


—carried by conveying head


14




b


immediately downstream from conveying head


14




a


in direction


17


, and having an outer tab


22


already folded as described above relative to tubular wrapping


5




a


and maintained folded by tooth


68


—gradually moves into position (

FIG. 1

) in front of folding edge


54


, which, as rocker arm


46


(

FIGS. 2

,


3


and


4


) moves into the work position, gradually folds the inner tab


22


of tubular wrapping


5




b


onto the already folded outer tab


22


without engaging tooth


68


, and onto the relative end of group


3


to close the end of tubular wrapping


5




b


completely and obtain a complete wrapping


25


.




At the output of folding station


24


, the complete wrapping


25


is fed by relative conveying head


14




b


beneath a tooth


69


coplanar with but wider than tooth


68


, and which keeps tabs


22


in the folded position.



Claims
  • 1. A method of closing the ends of tubular wrappings enclosing respective groups of cigarettes, each tubular wrapping (5) including a first major wall and a second major wall (6), a first minor wall and a second minor wall (7) perpendicular to said major walls (6), and at least one substantially rectangular-section tubular end portion (8) projecting axially with respect to the relative said group (3), the tubular end portion (8) including two short sides (9) coplanar with respective said minor walls (7), and two long sides (10) coplanar with respective said major walls (6), the method comprising:folding the short sides (9) of each tubular wrapping (5) onto the relative said group (3) to define on the relative said long sides (10) a first tab and a second tab (22) coplanar with said first major wall and said second major wall (6) respectively; folding the tabs (22) successively onto the relative said group (3), the tabs being folded towards each other such that when folding each said tab (22), the major wall (6) that is coplanar with tab (22) being folded is maintained parallel to and contacting a respective flat supporting wall (16, 60); maintaining a first said supporting wall (16) in contact with said first major wall (6); and moving a second said supporting wall (60) between a contact position contacting said second major wall (6) and a rest position.
  • 2. The method of claim 1, further comprising feeding the tubular wrapping along a path (P) parallel to said major walls (6) wherein said two tabs (22) are folded as the relative said tubular wrapping (5) is fed along the path (P), both said tabs (22) being folded successively by a single rocker arm (46) mounted to swing about a hinge axis (49) crosswise to said path (P) and comprising two folding arms (45, 50) located on opposite sides of said hinge axis (49), each folding arm (45, 50) having a respective folding edge (51; 54) for a respective said tab (22), said rocker arm (46) being swung about said hinge axis (49) so that each said folding edge (51; 54) interferes with said path (P) in time with said tubular wrappings (5) traveling along the path (P).
  • 3. The method of claim 2, wherein said path (P) is an annular path.
  • 4. The method of claim 3, further comprising feeding said tubular wrappings (5), together with the relative groups (3), continuously in a given traveling direction (17), and by means of respective conveying heads (14) on a wrapping wheel (11) of a cigarette packing machine (1), along said annular path (P), which extends about a rotation axis (12) of said wrapping wheel (11) and through a first and a second folding station (21, 24);positioning each tubular wrapping (5) on the relative said conveying head (14) with a longitudinal axis of the tubular wrapping parallel to said rotation axis (12); positioning said minor walls (7) substantially radially with respect to said rotation axis (12), said short sides (9) of each said tubular end portion (8) being folded onto the relative said group (3) when traveling through said first folding station (21), and said tabs (22) being folded successively onto the relative said group (3) and one towards the other when traveling through said second folding station (24).
  • 5. The method of claim 4, wherein for each said tubular wrapping (5), a first said supporting wall (16) is a wall integral with a relative said conveying head (14), whereas a second said supporting wall (60) is common to said conveying heads (14), and is located at said second folding station (24), the method further comprising:moving the second said supporting wall (60) towards said annular path (P) and into said contact position when folding each said second tab (22); and moving the second said supporting wall (60) when folding each said second tab (22), so as to keep the second supporting wall (60) constantly parallel to the relative first supporting wall (16).
  • 6. The method of claim 4, wherein said hinge axis (49) is located outwards of said annular path (P) and is parallel to said rotation axis (12), said rocker arm (46) being common to all said conveying heads (14).
  • 7. The method of claim 6, wherein said folding edges (51, 54) are separated by a distance substantially equal to a distance between two adjacent said conveying heads (14a, 14b) along said annular path (P), the method further comprising:causing said folding edges (51, 54) to interfere with said annular path (P) inside said second folding station (24), so that a first (51) of said folding edges (51, 54) folds said first tab (22) of one of said tubular wrappings (5) carried by a first said conveying head (14a), and, simultaneously, a second (54) of said folding edges (51, 54) folds a said second tab (22) of a said tubular wrapping (5) carried by a second said conveying head (14b) adjacent to said first conveying head (14a).
  • 8. The method of claim 7, wherein said first conveying head (14a) and said first folding edge (51) are located upstream from said second conveying head (14b) and said second folding edge (54) respectively in said traveling direction (17).
  • 9. The method of claim 4, wherein said first folding station (21) is located upstream from said second folding station (24) in said traveling direction (17).
  • 10. The method of claim 9, wherein said short sides (9) of each said tubular wrapping (5) are folded by engaging a first of said short sides (9) by means of a movable folding member (37), and a second of said short sides (9) by means of a fixed folding member (42), said fixed folding member (42) and said movable folding member (37) being located at said first folding station (21) and being common to all said conveying heads (14), and said first short side (9) being located upstream from the respective said second short side (9) in said traveling direction (17).
  • 11. The method of claim 10, wherein said fixed folding member (42) is located along said annular path (P), the method further comprising moving said movable folding member (37) along said annular path (P) and in said traveling direction (17) firstly with respect to said tubular wrapping (5) to fold the relative first short side (9), and then together with said tubular wrapping (5) and into substantial contact with said fixed folding member (42) to keep the first short side (9) in the folded position.
  • 12. A method of closing the ends of tubular wrappings enclosing respective groups of cigarettes, each tubular wrapping (5) including a first major wall and a second major wall (6), a first minor wall and a second minor wall (7) perpendicular to said major walls (6), and at least one substantially rectangular-section tubular end portion (8) projecting axially with respect to the relative said group (3), the tubular end portion (8) including two short sides (9) coplanar with respective said minor walls (7), and two long sides (10) coplanar with respective said major walls (6), the method comprising:feeding the tubular wrapping (5) in a traveling direction along a path (P) parallel to said major walls (6); folding the short sides (9) of each tubular wrapping (5) onto the relative said group (3) to define on the relative said long sides (10) a first tab and a second tab (22) coplanar with said first major wall and said second major wall (6) respectively; and folding the tabs (22) successively onto the relative said group with a single rocker arm (46) mounted to swing about a hinge axis (49) crosswise to said path (P) and comprising two folding arms (45, 50) located on opposite sides of said hinge axis (49) the folding arms each having a respective folding edge (51; 54) for a respective said tab (22), said rocker arm (46) being swung about said hinge axis (49) so that each said folding edge (51; 54) interferes with said path (P) in time with said tubular wrapping (5) traveling along the path (P).
  • 13. The method of claim 12, wherein said path (P) is an annular path.
  • 14. The method of claim 13, further comprising feeding said tubular wrappings (5), together with the relative groups (3), continuously in said traveling direction (17), and by means of respective conveying heads (14) on a wrapping wheel (11) of a cigarette packing machine (1), along said annular path (P), which extends about a rotation axis (12) of said wrapping wheel (11) and through a first and a second folding station (21, 24);positioning each tubular wrapping (5) on the relative said conveying head (14) with a longitudinal axis of the tubular wrapping parallel to said rotation axis (12); positioning said minor walls (7) substantially radially with respect to said rotation axis (12), said short sides (9) of each tubular wrapping (5) being folded onto the relative said group (3) when traveling through said first folding station (21), said tabs (22) being folded successively onto the relative said group (3) and one towards the other when traveling through said second folding station (24).
  • 15. The method of claim 14, wherein said hinge axis (49) is located outwards of said annular path (P) and is parallel to said rotation axis (12), said rocker arm (46) being common to all said conveying heads (14).
  • 16. The method of claim 15, wherein said folding edges (51, 54) are separated by a distance substantially equal to a distance between two adjacent said conveying heads (14a, 14b) along said annular path (P), the method comprising:causing said folding edges (51, 54) to interfere with said annular path (P) inside said second folding station (24), so that a first (51) of said folding edges (51, 54) folds said first tab (22) of a said tubular wrapping (5a) carried by a first said conveying head (14a), and, simultaneously, a second (54) of said folding edges (51, 54) folds said second tab (22) of a said tubular wrapping (5b) carried by a second said conveying head (14b) adjacent to said first conveying head (14a).
  • 17. The method of claim 16, wherein said first conveying head (14a) and said first folding edge (51) are located upstream from said second conveying head (14b) and said second folding edge (54) respectively in said traveling direction (17).
  • 18. The method of claim 14, wherein said first folding station (21) is located upstream from said second folding station (24) in said traveling direction (17).
  • 19. The method of claim 14, wherein, for each said tubular wrapping (5), said first supporting wall (16) is a wall integral with a relative said conveying head (14), whereas said second supporting wall (60) is common to said conveying heads (14), is moved towards said annular path (P) and into said contact position when folding each said second tab (22), and is moved, when folding each said second tab (22), so as to keep the second supporting wall (60) constantly parallel to the relative first supporting wall (16).
  • 20. The method of claim 12, wherein said short sides (9) of each said tubular wrapping (5) are folded by engaging a first of said short sides (9) by means of a movable folding member (37), and a second of said short sides (9) by means of a fixed folding member (42), each said tubular wrapping (5) being brought into engagement with said fixed folding member (42) and said movable folding member (37), and said first short side (9) being located upstream from the respective said second short side (9) in said traveling direction (17).
  • 21. The method of claim 20, wherein said fixed folding member (42) is located along said path (P), the method further comprising moving said movable folding member (37) along said path (P) and in said traveling direction (17) firstly with respect to said tubular wrapping (5) to fold the relative first short side (9), and then together with said tubular wrapping (5) and into substantial contact with said fixed folding member (42).
  • 22. The method of claim 12, wherein, at least when folding each said tab (22), said major wall (6) coplanar with said tab (22) is maintained parallel to and contacting a respective flat supporting wall (16; 60).
  • 23. The method of claim 22, wherein a first said supporting wall (16) is maintained permanently contacting said first major wall (6), whereas a second said supporting wall (60) is a movable wall, which is moved to and from a contact position contacting said second major wall (6).
  • 24. A unit for closing the ends of tubular wrappings enclosing respective groups of cigarettes, each tubular wrapping (5) comprising a first and a second major wall (6), a first and a second minor wall (7) perpendicular to said major walls (6), and at least one substantially rectangular-section tubular end portion (8) projecting axially with respect to the relative said group (3) and in turn comprising two short sides (9) coplanar with respective said minor walls (7), and two long sides (10) coplanar with respective said major walls (6); the unit comprising:first folding means (37, 42) for folding said short sides (9) of each tubular wrapping (5) onto the relative said group (3) to define a tab (22) on each said long side (10); second folding means (46) for folding said tabs (22) successively onto the relative said group (3) and one towards the other; two flat supporting walls (16, 60); actuating means (62, 66, 67) for maintaining said two flat supporting walls (16, 60) parallel to each other and each contacting a respective said major wall (6), at least when folding the tab (22) coplanar with said major wall (6); a first folding station and a second folding station (21, 24) located successively along a path (P): conveying means (11) for feeding said tubular wrappings (5) successively along said given path (P) and in a given traveling direction (17), said conveying means (11) comprising a number of conveying heads (14), each for housing a respective said tubular wrapping (5), each tubular wrapping (5) being positioned on the relative said conveying head (14) with a longitudinal axis of the tubular wrapping crosswise to said traveling direction (17), wherein a first said supporting wall (16) is a wall of said conveying head (14), and is positioned parallel to and contacting said first major wall (6) coplanar with a first said tab (22); and a second said supporting wall (60) is a movable wall common to all the conveying heads (14), and said actuating means (62, 66, 67) being connected to said second supporting wall (60) to move the second supporting wall (60) to and from a contact position contacting a said tubular wrapping (5) located at said second folding station (24), and to position said second supporting wall (60), in said contact position, contacting said second major wall (6) coplanar with a respective second said tab (22).
  • 25. The unit of claim 24, wherein said second folding means (46) comprise a single rocker arm (46), which folds both said tabs (22) as the relative tubular wrapping (5) is fed through said second folding station, said rocker arm (46) being mounted to rotate about a hinge axis (49) crosswise to said path (P), and comprising two folding arms (45, 50) located on opposite sides of said hinge axis (49) and each folding arm having a respective folding edge (51; 54) for a respective said tab (22), and first actuating means (26, 56) for swinging said rocker arm (46) so that said folding edges (51, 54) interfere with said path (P) in time with each said conveying head (14) traveling along the path (P).
  • 26. The unit of claim 25, wherein said conveying means (11) comprise a wrapping wheel (11) mounted to rotate continuously about a rotation axis (12) crosswise to said path (P), and a number of said conveying heads (14) equally spaced about said rotation axis (12), said path (P) being an annular path (P) extending about said rotation axis (12), and each said conveying head (14) being so formed as to support the relative said tubular wrapping (5) with the relative said minor walls (7) positioned substantially radially with respect to said rotation axis (12).
  • 27. The unit of claim 26, wherein said actuating means (62, 66, 67) keep said second supporting wall (60) in said contact position and parallel to said first supporting wall (16) of a tubular wrapping (5) located in said second folding station (24) when folding said second tab (22) of said tubular wrapping (5) and as the tubular wrapping (5) is fed along at least part of said second folding station (24).
  • 28. The unit of claim 26, wherein said hinge axis (49) is located in a fixed position outwards of said annular path (P), and is parallel to said rotation axis (12), said rocker arm (46) being common to all said conveying heads (14).
  • 29. The unit of claim 28, wherein said folding edges (51, 54) are separated by a distance substantially equal to a distance between two adjacent said conveying heads (14a, 14b) along said path (P).
  • 30. The unit of claim 28, wherein said first actuating means (26, 56) comprise a first articulated quadrilateral (56) in turn comprising a powered crank (29) powered to rotate about a first motor axis (27) parallel to said rotation axis (12), a driven crank (55) integral with said rocker arm (46) and rotating with the rocker arm (46) about said hinge axis (49), and a connecting rod (57) connecting said cranks (29, 55) to each other.
  • 31. The unit of claim 30, further comprising one motor (26) for powering both said powered cranks (33, 29), said first and second motor axes (27) being coincident with each other.
  • 32. The unit of claim 24, wherein said first folding station (21) is located upstream from said second folding station (24) in said traveling direction (17).
  • 33. The unit of claim 24, wherein said first folding means (37, 42) comprise a movable folding member (37) for folding a first of said short sides (9), a fixed folding member (42) for folding a second of said short sides (9), and second actuating means (26, 41) for moving said movable folding member (37) to and from a position substantially contacting said fixed folding member (42), said movable and fixed folding members (37, 42) being located at said first folding station (21), and being common to all said conveying heads (14), and said movable folding member (37) being located upstream from said fixed folding member (42) in said traveling direction (17).
  • 34. The unit of claim 33, wherein said second actuating means (26, 41) comprise a second articulated quadrilateral (41) in turn comprising a further powered crank (33) powered to rotate about a second motor axis (27) parallel to said rotation axis (12), a further driven crank (39) rotating about a fixed axis (40) parallel to said second motor axis (27), and a further connecting rod (34) connecting said further cranks (33, 39) and integral with said movable folding member (37).
  • 35. The unit of claim 34, wherein said fixed axes (40) are coincident with each other.
  • 36. The unit of claim 24, wherein said actuating means (62, 66, 67) comprise an articulated polygon (62) in turn comprising two powered cranks (63, 64), a first connecting rod defined by a pad (60) defining said second supporting wall (60) and hinged to a first said crank (63), and a second connecting rod (65) connecting said pad (60) to a second said crank (64).
  • 37. The unit of claim 36, wherein said two powered cranks (63, 64) are mounted to rotate about a same fixed axis (40) parallel to said rotation axis (12).
  • 38. A unit for closing the ends of tubular wrappings enclosing respective groups of cigarettes, each tubular wrapping (5) comprising a first and a second major wall (6), a first and a second minor wall (7) perpendicular to said major walls (6), and at least one substantially rectangular-section tubular end portion (8) projecting axially with respect to the relative said group (3) and in turn comprising two short sides (9) coplanar with respective said minor walls (7), and two long sides (10) coplanar with respective said major walls (6); the unit comprising:first folding means (37, 42) located at a first folding station (21) to fold said short sides (9) of each tubular wrapping (5) onto the relative said group (3) to define a tab (22) on each said long side (10); first actuating means (26, 41) for actuating said first folding means (37, 42); second folding means (46) located at a second folding station (24) to fold said tabs (22) successively onto the relative said group (3) and one towards the other; second actuating means (26, 56) for actuating said second folding means (46); and conveying means (11) for feeding said tubular wrappings (5) successively and continuously in a given traveling direction (17) and along a path (P) extending through said first and said second folding station (21, 24); wherein said second folding means (46) comprise a single rocker arm (46), which successively folds both said tabs (22) of each said tubular wrapping (5) as the tubular wrapping (5) is fed through said second folding station (24), said rocker arm (46) being mounted to rotate about a hinge axis (49) crosswise to said path (P), and comprising two folding arms (45, 50) located on opposite sides of said hinge axis (49) and each folding arm having a respective folding edge (51; 54) for a respective said tab (22), and said second actuating means (26, 56) swinging said rocker arm (46) so that said folding edges (51, 54) interfere with said path (P) in time with said conveying means (11).
  • 39. The unit of claim 38, further comprising two flat supporting walls (16, 60), each of which is maintained parallel to and contacting a respective said major wall (6) at least when folding the relative said tab (22).
  • 40. The unit of claim 39, wherein a first said supporting wall (16) is a fixed wall of said conveying head (14), which supports a relative said tubular wrapping (5) with said first major wall (6) parallel to and contacting the relative said fixed wall and coplanar with a respective first said tab (22), a second said supporting wall (60) is a movable wall common to all the conveying heads (14), and third actuating means (62, 66, 67) are provided to move said second supporting wall (60) to and from a contact position contacting said tubular wrapping (5) located at said second folding station (24), said second supporting wall (60) being positioned, in said contact position, contacting said second major wall (6) and coplanar with a respective second said tab (22).
  • 41. The unit of claim 40, wherein third actuating means (62, 66, 67) keep said second supporting wall (60) in said contact position and parallel to said first supporting wall (16) of a tubular wrapping (5) located in said second folding station (24) when folding said second tab (22) of said tubular wrapping (5) and as the tubular wrapping (5) is fed along at least part of said second folding station (24).
  • 42. The unit of claim 41, wherein said third actuating means (62, 66, 67) comprise an articulated polygon (62) in turn comprising a first and a second powered crank (63, 64), a first connecting rod defined by a pad (60) defining said second supporting wall (60) and hinged to said first crank (63), and a second connecting rod (65) connecting said pad (60) to said second crank (64).
  • 43. The unit of claim 42, wherein said two powered cranks (63, 64) are mounted to rotate about a same fixed axis (40) parallel to said rotation axis (12).
  • 44. The unit of claim 38, wherein said conveying means (11) comprise a number of conveying heads (14), each for housing a respective said tubular wrapping (5) positioned with a longitudinal axis of the tubular wrapping crosswise to said traveling direction (17).
  • 45. The unit of claim 44, wherein said first folding means (37, 42) comprise a movable folding member (37) for folding a first of said short sides (9), and a fixed folding member (42) located along said path (P) to fold a second of said short sides (9), said first actuating means (26, 41) moving said movable folding member (37) along said path (P) to and from a position substantially contacting said fixed folding member (42), said movable and fixed folding members (37, 42) being located at said first folding station (21), and being common to all said conveying heads (14), and said movable folding member (37) being located upstream from said fixed folding member (42) in said traveling direction (17).
  • 46. The unit of claim 45, wherein said first actuating means (26, 41) comprise a second articulated quadrilateral (41) in turn comprising a further powered crank (33) powered to rotate about a motor axis (27) parallel to said rotation axis (12), a further driven crank (39) rotating about a fixed axis (40) parallel to said motor axis (27), and a further connecting rod (34) connecting said further cranks (33, 39) and integral with said movable folding member (37).
  • 47. The unit of claim 38, wherein said conveying means (11) comprise a wrapping wheel (11) mounted to rotate continuously about a rotation axis (12) crosswise to said path (P), and a number of said conveying heads (14) equally spaced about said rotation axis (12), said path (P) being an annular path (P) extending about said rotation axis (12), and each said conveying head (14) being so formed as to support the relative said tubular wrapping (5) with a relative longitudinal axis parallel to said rotation axis (12), and with the relative said minor walls (7) positioned substantially radially with respect to said rotation axis (12).
  • 48. The unit of claim 47, wherein said hinge axis (49) is located in a fixed position outwards of said annular path (P), and is parallel to said rotation axis (12), said rocker arm (46) being common to all said conveying heads (14).
  • 49. The unit of claim 48, wherein said second actuating means (26, 56) comprise a first articulated quadrilateral (56) in turn comprising a powered crank (29) powered to rotate about a motor axis (27) parallel to said rotation axis (12), a driven crank (55) integral with said rocker arm (46) and rotating with the rocker arm (46) about said hinge axis (49), and a first connecting rod (57) connecting said cranks (29, 55) to each other.
  • 50. The unit of claim 49, further comprising one motor (26) for powering both said powered cranks (29, 33), said motor axes (27) of said two powered cranks (29, 33) being coincident with each other.
  • 51. The unit of claim 47, wherein said folding edges (51, 54) are separated by a distance substantially equal to a distance between two adjacent said conveying heads (14a, 14b) along said annular path (P).
  • 52. The unit of claim 38, wherein said first folding station (21) is located upstream from said second folding station (24) in said traveling direction (17).
Priority Claims (1)
Number Date Country Kind
BO2000A0258 May 2000 IT
US Referenced Citations (3)
Number Name Date Kind
3810314 Anderson May 1974 A
4736569 Hudson et al. Apr 1988 A
4845924 Focke et al. Jul 1989 A
Foreign Referenced Citations (2)
Number Date Country
0 845 416 Jun 1998 EP
718 291 Jan 1932 FR