Method for producing a pack for groups of products and machine for implementing said method

Abstract

A method for producing a pack ( 1 ) for groups ( 2 ) of rolls of products comprises the following steps: forming of a tube of film ( 3 ) around a frame ( 5 ) forming a channel ( 6 ) for the passage of the product groups ( 2 ); creation of a first seal (S 1 ) on the front edges ( 7 ) of the film ( 3 ); insertion in the channel ( 6 ) of product groups ( 2 ), fed until they are close to the closed front end ( 7 ) of the film ( 3 ); further feeding of the product groups ( 2 ) with simultaneous feeding of the film ( 3 ) and formation of the further portion of the pack ( 1 ) beyond the frame ( 5 ); creation of a second, longitudinal seal (S 2 ) on the overlapping longitudinal edges of the film ( 3 ) simultaneously with the further feed step; creation of a third seal (S 3 ) on the rear edges ( 11 ) of the film ( 3 ) designed to close the pack ( 1 ) at the rear of the product groups ( 2 ) bagged; between the step of insertion of product groups ( 2 ) in the channel ( 6 ) and the further feeding of the product groups ( 2 ), there being a step of feeding the film ( 3 ) wound around the frame ( 5 ), simultaneously with and in the same direction as the feeding of the product groups ( 2 ), designed to allow a fixed distance (D) to be maintained between the closed front end ( 7 ) of the film ( 3 ) and the front end ( 2 a ) of the product groups ( 2 ) fed forward.

1 . A bagging machine for producing a pack ( 1 ) for product groups ( 2 ); the machine ( 100 ) being of the type comprising at least:
 a frame ( 5 ) comprising folder means ( 4 ) designed to support a packaging film ( 3 ), which is wound around the folder means ( 4 ) and can be fed from a station ( 13 ); the frame ( 5 ) forming a channel ( 6 ) for the passage of the product groups ( 2 ) fed forward by pusher means ( 9 ) in a direction of feed (A);   first, transversal sealing means ( 8 ), positioned downstream of the frame ( 5 ), relative to the direction of feed (A), and designed to join, respectively, the front edges ( 7 ) of the packaging film ( 3 ), before arrival of the product groups ( 2 ), and the rear edges ( 11 ) after the product groups ( 2 ) wrapped in the packaging film ( 3 ) have passed beyond the first sealing means ( 8 );   second, longitudinal sealing means ( 10 ), positioned close to the frame ( 5 ) and designed to join two longitudinal edges of the film ( 3 ) when the pack ( 1 ) is formed,   the machine ( 100 ) further comprising film ( 3 ) feed means ( 14 ) positioned close to the frame ( 5 ) and designed to allow film ( 3 ) feed in the same direction as the direction of feed (A), when the product groups ( 2 ) move towards the sealed front edges ( 7 ) of the film ( 3 ), and maintaining a fixed distance (D) between the sealed front edges ( 7 ) and the front end ( 2   a ) of the product groups ( 2 ) fed forward.   
   
   
       2 . The machine according to  claim 1 , wherein the feed means ( 14 ) are positioned between the frame ( 5 ) and the first sealing means ( 8 ), forming a stretch of the frame ( 5 ). 
   
   
       3 . The machine according to  claim 1 , wherein the feed means ( 14 ) are positioned between the frame ( 5 ) and the first sealing means ( 8 ) and evenly distributed around the channel ( 6 ) formed by the frame ( 5 ). 
   
   
       4 . The machine according to  claim 3 , wherein the feed means ( 14 ) form a final stretch of the frame ( 5 ). 
   
   
       5 . The machine according to  claim 4 , wherein the feed means ( 14 ) comprise a plurality of film ( 3 ) feed belts ( 15 ), positioned around the frame ( 5 ), and forming the final stretch of the frame ( 5 ), at least partly completing the channel ( 6 ) along all of its sides. 
   
   
       6 . The machine according to  claim 5 , comprising a first set ( 15 ) of upper belts and a second set ( 16 ) of lower belts opposite one another and present in equal numbers. 
   
   
       7 . The machine according to  claim 6 , wherein each belt ( 14 ) of the first and second sets ( 15 ,  16 ) is positioned coplanar with the extension of the frame ( 5 ). 
   
   
       8 . The machine according to  claim 5 , comprising a third set ( 17 ) and a fourth set ( 18 ) of lateral belts ( 14 ) opposite one another and present in equal numbers. 
   
   
       9 . The machine according to  claim 8 , wherein each belt ( 14 ) of the third and fourth sets ( 17 ,  18 ) is positioned coplanar with the extension of the frame ( 5 ). 
   
   
       10 . The machine according to  claim 8 , wherein each of the belts ( 14 ) of the third and fourth sets ( 17 ,  18 ) is positioned at an angle to the extension of the frame ( 5 ), that is to say projecting into the channel ( 6 ), and its position can be adjusted according to the contact with the film ( 3 ) and the product groups ( 2 ) fed forward. 
   
   
       11 . The machine according to  claim 10 , wherein each belt ( 14 ) is closed in a loop on a respective shaped support ( 20 ) designed to allow the formation of an active branch ( 14   a ) for making contact with and feeding the film ( 3 ) simultaneously with the feeding of the product groups ( 2 ); each support ( 20 ) being associated with a supporting base ( 21 ) shared by each of the first, second, third and fourth sets ( 15 ,  16 ,  17 ,  18 ) of belts ( 14 ). 
   
   
       12 . The machine according to  claim 11 , wherein each shaped support ( 20 ) has at least a first pair of idle wheels ( 22 ,  22   a ) on which the belt ( 14 ) runs around the shaped support ( 20 ), and a second wheel ( 23 ) keyed on a transmission and supporting shaft ( 24 ), transverse to each shaped support ( 20 ), and shared by each set ( 15 ,  16 ,  17 ,  18 ) of belts ( 14 ). 
   
   
       13 . The machine according to  claim 11 , wherein each of the belts ( 14 ) may rotate idly along the shaped support ( 20 ) and may be moved by means of pressure on the film ( 3 ) when the product groups ( 2 ) pass. 
   
   
       14 . The machine according to  claim 12 , wherein at least the first and second sets ( 15 ,  16 ), upper and lower, are motor-driven, by a single drive unit ( 25 ) connected to a kinematic motion transmission system ( 26 ) positioned at the ends of the respective transmission and supporting shafts ( 24 ). 
   
   
       15 . The machine according to  claim 12 , wherein the third and fourth sets ( 17 ,  18 ) of belts ( 14 ) are motor-driven by corresponding independent drive units ( 17   m,    18   m ). 
   
   
       16 . The machine according to  claim 11 , wherein at least the first set ( 15 ) of upper belts ( 14 ) is subject to an actuator ( 27 ), positioned above the channel ( 6 ), acting vertically on each shaped support ( 20 ) and designed to apply a pressure on the feed belts ( 14 ) to allow them to constantly adhere to the film ( 3 ) and the product groups ( 2 ) passing; there being damper means ( 28 ) acting between the actuator ( 27 ) and the shaped supports ( 20 ), to allow both constant adjustment of the contact between the belts ( 14 ) and the film ( 3 ) in contact with the product groups ( 2 ), and movement of the belts ( 14 ) away from the film ( 3 ) upon the release of the pressure applied by the actuator ( 27 ) simultaneously with sealing of the rear edges ( 11 ) of a pack ( 1 ). 
   
   
       17 . The machine according to  claim 12 , wherein each of the third and fourth sets ( 17 ,  18 ) of belts ( 14 ) comprises a pair of belts ( 14   b,    14   c ) connected, with the support ( 20 ), to a vertical guide ( 29 ); each upper belt ( 14   b ) being integral, by means of a rod ( 30 ), with the first set ( 15 ) of upper belts ( 14 ) so as to maintain a constant distance from the first set ( 15 ) of belts ( 14 ) according to a vertical movement of the first set ( 15 ) of belts ( 14 ). 
   
   
       18 . The machine according to  claim 17 , wherein the third and fourth sets ( 17 ,  18 ) of belts ( 14 ) are controlled by a cylinder ( 31 ), acting perpendicularly on the corresponding vertical guide ( 29 ) to obtain a variation of the position of the sets of belts, moving them towards or away from one another, depending on the configurations of the product groups ( 2 ), and moving the film ( 3 ) away when the rear edges ( 11 ) of a pack ( 1 ) are sealed. 
   
   
       19 . The machine according to  claim 17 , wherein each of the third and fourth sets ( 17 ,  18 ) of lateral belts ( 14 ) has positioning means ( 19 ) for the angle of inclination of each belt ( 14 ); each of the positioning means ( 19 ) comprising at least a curved slot ( 33 ) made in a mobile portion ( 20   a ) of the shaped support ( 20 ), allowing predetermined angular positioning of the belts ( 14 ).