Device For Driving The Folding Arms Of An Interfolding Machine

Abstract

The device for driving folding arms of comb-like folding means along a closed operating path is used on an interfolding machine 100 for production of interfolded packs of sheets of tissue paper or another material and is mounted on a frame 10 a situated in the lower part of the machine 100 . A connecting rod-crank transmission assembly 13 is mounted on the frame 10 a and connected to the comb-like 2 , to drive the latter along the closed operating path. The driving device 10 comprises also a main motor 51 , aimed at supplying at least a part of mechanical power necessary to drive the comb-like 2 , and a supplementary motor 55 , running at a controllable rotation speed, aimed at cooperating with the main motor 11 , in driving the comb-like 2 . An epicycloidal type differential 20 , connected mechanically to the main and supplementary motors 51 and 55 , and to the transmission assembly 13 as the combination of the power received at the intakes. A control unit is also provide in the interfolding machine 100 for adjusting the rotation speed induced by the supplementary motor 55 in relation to the position assumed by the folding arms 3 in the above-mentioned operating path.

1 - 11 . (canceled) 
     
     
         12 . A device for driving folding arms in an interfolding machine for manufacturing interfolded packs of sheet articles, said interfolding machine ( 100 ) comprising:
 one or more folding rollers ( 110   a ,  110   b ), each folding roller receiving in sequence a plurality of sheet articles ( 1 ) to be stacked;   comb-like folding means ( 2 ) having a plurality of folding arms ( 3 ), being arranged near each of said one or more folding rollers, each comb-like folding means having a longitudinal axis thereof substantially parallel to an axis of a corresponding one of said one or more folding rollers, said folding arms ( 3 ) being movable, in suitable phase relation with the rotation of said one or more folding rollers, along a closed operating path defined by a driving device ( 10 ) to withdraw periodically therefrom a sheet article and to stack each sheet article to form corresponding packs of sheet articles;   said driving device ( 10 ) having:   a frame ( 10   a );   motor means ( 50 ) having an electronically controllable rotation speed, said motor means providing rotation mechanical power for driving said comb-like folding means ( 2 );   mechanical transmission means ( 13 ), mounted on said frame ( 10   a ), and being connected to said comb-like folding means ( 2 ) and to a transmission shaft ( 14 ), connected in turn to said motor means ( 50 ), said mechanical transmission means using said rotation mechanical power for providing controlled oscillations of said folding means ( 2 ) to drive said folding arms ( 3 ) along said closed operating path;   a programmable control unit, connected to said motor means ( 50 ) and provided with a processing program, for regulating the rotation speed of said motor means ( 50 ) in relation to a position assumed by said folding arms ( 3 ) traveling along the closed operating path.   
     
     
         13 . The device as claimed in  claim 12 , wherein said motor means ( 50 ) comprise a single electric motor with a controllable speed, operable independently from the driving of said interfolding machine. 
     
     
         14 . The device as claimed in  claim 13 , wherein said single electric motor is a brushless type motor. 
     
     
         15 . The device as claimed in  claim 13 , wherein said single electric motor is an electric asynchronous motor or an electric stepping motor. 
     
     
         16 . The device as claimed in  claim 12 , wherein said motor means ( 50 ) comprise:
 main motor means ( 51 ), operable at a predetermined speed, for supplying at least a part of the rotational mechanical power necessary for driving said comb-like folding means ( 2 );   supplementary motor means ( 55 ), operable at a controllable rotation speed, for cooperating with said main motor means in driving said comb-like folding means;   differential transmission means ( 20 ), mounted on said frame ( 10   a ), and being connected mechanically to said main motor means ( 51 ), to said supplementary motor means ( 55 ) and to said mechanical transmission means ( 13 ), for receiving at an intake thereof, rotational mechanical power generated respectively by said main motor means and said supplementary motor means, and for supplying a corresponding rotational mechanical power to said mechanical transmission means ( 13 ), with a speed defined by a combination of the speeds of said main motor means and said supplementary motor means;   said programmable control unit adjusting the rotation speed induced by said supplementary motor means in relation to the position assumed by said folding arms ( 3 ) in said closed operating path.   
     
     
         17 . The device as claimed in  claim 16 , wherein said differential transmission means ( 20 ) comprise an epicycloidal type mechanical differential, provided with a first power intake ( 21 ), connected to said main motor means ( 51 ), with a second axial power intake ( 22 ), connected to said supplementary motor means ( 55 ), and with a power take-off ( 23 ), arranged axially with said second power intake ( 22 ), said power take-off ( 23 ) connected to said mechanical transmission means ( 13 ), a rotation speed of said power take-off being defined by a combination of the rotation speed induced by said main motor means ( 51 ) in the first power intake ( 21 ) and the speed induced by said supplementary motor means ( 55 ) in the second power intake ( 22 ). 
     
     
         18 . The device as claimed in  claim 16 , wherein said supplementary motor means ( 55 ) includes a brushless type position controllable motor. 
     
     
         19 . The device as claimed in  claim 17 , wherein said supplementary motor means ( 55 ) includes a brushless type position controllable motor. 
     
     
         20 . The device as claimed in  claim 16 , wherein said supplementary motor means ( 55 ) includes an asynchronous motor or an electric stepping motor. 
     
     
         21 . The device as claimed in  claim 17 , wherein said supplementary motor means ( 55 ) includes an asynchronous motor or an electric stepping motor. 
     
     
         22 . The device as claimed in  claim 16 , wherein said main motor means ( 51 ) are connected to said first power intake ( 21 ) by a mechanical transmission assembly ( 31 ) having a transmission belt ( 35 ), acting on said first power intake ( 21 ) of the differential transmission means ( 20 ). 
     
     
         23 . The device as claimed in  claim 17 , wherein said main motor means ( 51 ) are connected to said first power intake ( 21 ) by a mechanical transmission assembly ( 31 ) having a transmission belt ( 35 ), acting on the first power intake ( 21 ) of the epicycloidal type differential transmission means. 
     
     
         24 . The device as claimed in  claim 16 , wherein said supplementary motor means ( 55 ) include a first supplementary brushless motor ( 55   a ) and a second supplementary brushless motor ( 55   b );
 said differential transmission means ( 20 ) comprising a first mechanical differential ( 20   a ) and a second mechanical differential ( 20   b ), each mechanical differential being of the epicycloidal type;   the first mechanical differential ( 20   a ) and the second mechanical differential ( 20   b ) being oppositely mounted and axially aligned, each of the first and second mechanical differentials having a respective first power intake ( 21   a ,  21   b ) connected to said main motor means ( 51 ), and each having a respective second power intake ( 22   a ,  22   b ) connected to the respective first and second supplementary motors ( 55   a ,  55   b ), each of said first and second mechanical differentials ( 20   a ,  20   b ) having a respective power takeoff ( 23   a ,  23   b ), arranged axially with respect to each other and said second power intake, said first and second power take-offs being axially aligned and being connected to opposite sides of said mechanical transmission means ( 13 ), rotation speeds of said power take-offs being defined by a combination of a rotation speed induced by said main motor means at the respective first power intakes and a speed induced by each of said first and second supplementary motor means at the respective second power intakes, the rotation speed of each of said first and second supplementary motors being synchronized by a control unit of said interfolding machine.   
     
     
         25 . The device as claimed in  claim 24 , wherein said main motor means ( 51 ) are connected to said first power intake ( 21   a ) of said first mechanical differential by a mechanical transmission assembly ( 31 ) having a first transmission belt ( 35   a ) that acts on said first power intake ( 21   a ) of said first mechanical differential ( 20   a ), the main motor means ( 51 ) being also connected to said first power intake ( 21   b ) of said second mechanical differential ( 20   b ) by the mechanical transmission assembly ( 31 ) having a second transmission belt ( 35   b ) that acts on said first power intake ( 21   b ) of said second mechanical differential ( 20   b ).