System and method for forming and fanfolding a sheet material

1. A system ( 1 ) for forming and fanfolding a sheet material from a continuous web (M) of indefinite length having a bottom side (S 1 ), a top side (S 2 ) and longitudinal side edges (B), the system ( 1 ) comprising:

a frame ( 3 ′, 3 ″) defining a vertical center plane (π);

a feeding device having means for guiding the continuous web (M) in a longitudinal direction (L);

a creasing device ( 2 ) located downstream of said feeding device to form transverse creases (C 1 , C 2 ) on the continuous web (M) spaced apart at a constant longitudinal pitch (K) and defining adjacent partitions (P);

a folding device ( 14 ) located downstream of said creasing device ( 2 ) for progressively and alternately fanfolding the adjacent partitions (P) along the creases (C 1 , C 2 );

wherein said folding device ( 14 ) comprises at least one first group ( 15 ) of thrust tools ( 17 ) acting on the creases (C 1 ) formed on the bottom side (S 1 ) of the continuous web (M) and at least one second group ( 16 ) of thrust tools ( 18 ) acting on the creases (C 2 ) formed on the top side (S 2 ) of the continuous web (M), the thrust tools ( 17 , 18 ) of each group ( 15 , 16 ) being mechanically connected to and operably dependent on each other so that all the tools ( 17 , 18 ) of the same group ( 15 , 16 ) are forced to follow the same trajectory (T 1 , T 2 ), the thrust tools ( 17 , 18 ) of the same group ( 15 , 16 ) being supported at the free ends of first series ( 27 ) and second series of articulated arms ( 28 ).

2. The system as claimed in claim 1 , wherein said frame ( 3 ″) has mounted thereto a first operating assembly ( 19 ) for supporting and moving said first group ( 15 ) of thrust tools ( 17 ) and a second operating assembly ( 20 ) distinct from and independent of the first operating assembly ( 19 ), for supporting and moving said second group ( 16 ) of thrust tools ( 18 ).

3. The system as claimed in claim 2 , wherein said first operating assembly ( 19 ) comprises a first pair of supporting wheels ( 21 ) facing each other about said vertical center plane (π) and rigidly fixed to a first transverse shaft ( 23 ) driven by a first motor ( 24 ), the wheels of said first pair ( 21 ) being located at a first transverse distance (d 1 ) greater than the maximum width (E) of the continuous web (M).

4. The system as claimed in claim 3 , wherein said second operating assembly ( 20 ) comprises a second pair of supporting wheels ( 22 ) facing each other about said vertical center plane (π) and rigidly fixed to a second transverse shaft ( 25 ) driven by a second motor ( 26 ), the wheels of said second pair ( 22 ) being located at a second transverse distance (d 2 ) greater than said first transverse distance (d 1 ).

5. The system as claimed in claim 4 , wherein said first transverse shaft ( 23 ) and said second transverse shaft ( 25 ) are rotatably mounted to said frame ( 3 ″) in longitudinally offset positions, with said second shaft ( 25 ) downstream of the first shaft ( 23 ).

6. The system as claimed in claim 3 , wherein said first series of articulated arms ( 27 ) are mounted proximate to a peripheral edge ( 21 ′) of said first pair of wheels ( 21 ), and are each driven by a respective first drive ( 28 ) having a transverse axis (X 5 ) that is perpendicular to said center plane (π).

7. The system as claimed in claim 4 , wherein said second series of articulated arms ( 29 ) are mounted proximate to a peripheral edge ( 22 ′) of said second pair of wheels ( 22 ), and are each driven by a respective second drive ( 30 ) having a transverse axis (X 6 ) that is perpendicular to said center plane (π).

8. The system as claimed in claim 7 , wherein the articulated arms of said first series ( 27 ) are formed by respective first pairs of elongate members ( 31 ) connected to each other by third drives ( 32 ) having axes of oscillation (X 7 ) that are transverse and perpendicular to said center plane (π), said third drives ( 32 ) being configured to impart a relative oscillation to said elongate members ( 31 ) about said transverse axes of oscillation (X 7 ).

9. The system as claimed in claim 8 , wherein the articulated arms of said second series ( 29 ) are formed by respective second pairs of elongate members ( 33 ) connected to each other by fourth drives ( 34 ) having axes of oscillation (X 8 ) that are transverse and perpendicular to said center plane (π), said fourth drives ( 34 ) being configured to impart a relative oscillation to said elongate members ( 33 ) about said transverse axes of oscillation (X 8 ).

10. The system as claimed in claim 9 , wherein each thrust tool ( 17 , 18 ) is a substantially horizontal elongate member, which is transverse and perpendicular to said center plane (π).

11. The system as claimed in claim 9 , wherein said first drive ( 28 ) and second drive ( 30 ) and said third drives ( 32 ) and fourth drives ( 34 ) drives are cam type.

12. The system as claimed in claim 11 , wherein said first drive ( 28 ) and second drive ( 30 ) comprise a third motor ( 35 ) and a fourth motor ( 36 ) respectively, and said third drives ( 32 ) and fourth drives ( 34 ) comprise fifth motors ( 37 ) and sixth motors ( 38 ) respectively.

13. The system as claimed in claim 12 , wherein said first motor ( 24 ) and second motor ( 26 ), said third, fourth, fifth and sixth motors ( 35 - 38 ) are controlled by a control unit, which is able to set a first trajectory (T 1 ) and a second trajectory (T 2 ), which are differentiated and non-interfering trajectories, for said first group ( 15 ) and said second group ( 16 ) of thrust tools ( 17 , 18 ) respectively, said control unit being able to set a first path (W 1 ) and a second path (W 2 ) for the creases (C 1 ) of the bottom side (S 1 ) and for the creases (C 2 ) of the top side (S 2 ) respectively.

14. The system as claimed in claim 1 , wherein said creasing device ( 2 ) is configured to form creases (C 1 , C 2 ) alternately on the bottom side (S 1 ) and on the top side (S 2 ) of the continuous web (M).

15. A method of forming and fanfolding a sheet material from a continuous web (M) of indefinite length having a bottom side (S 1 ), a top side (S 2 ) and longitudinal side edges (B), said method comprising:

providing a device for feeding the continuous web (M) in a longitudinal direction (L);

providing a creasing device ( 2 ) downstream of said feeding device to form transverse creases (C 1 , C 2 ) on the continuous web (M), spaced apart at a constant longitudinal pitch (K) and defining adjacent partitions (P); and

providing a folding device ( 14 ), as claimed in claim 1 , downstream of the creasing device ( 2 ), having at least one first group ( 15 ) of thrust tools ( 17 ) and at least one second group ( 16 ) of thrust tools ( 18 ) for progressively and alternately fanfolding the adjacent partitions (P) along the creases (C 1 , C 2 );

wherein the creasing device ( 2 ) forms creases (C 1 , C 2 ) alternately on the bottom side (S 1 ) and on the top side (S 2 ) of the continuous web (M);

wherein the first group ( 15 ) of thrust tools ( 17 ) of the folding device ( 14 ) acts on the creases (C 1 ) formed on the bottom side (S 1 ) of the continuous web (M) and the second group ( 16 ) of thrust tools ( 18 ) acts on the creases (C 2 ) formed on the top side (S 2 ) of the continuous web (M);

wherein all the tools ( 17 , 18 ) of the same group ( 15 , 16 ) are mechanically connected to and operably dependent on each other and move along the same trajectory (T 1 , T 2 ).