Gable-top package for pourable food products and method for dimensioning thereof

Abstract

A gable top package for pourable food products produced by folding and sealing a sheet packaging material and provided with a gabled top portion including front and back sloping top walls joined together at a top transversal seal, and a pair of side top walls connecting respective lateral edges of the front and back sloping top walls and obtained by folding respective portions of the sheet packaging material along predetermined crease lines delimiting a number of panels. The crease lines are determined among a plurality of possible crease lines designed so as the forming of the side top walls is performed by rotations of the panels as rigid bodies about their respective crease lines.

1 . A gable top package for pourable food products produced by folding and sealing a sheet packaging material and comprising a gabled top portion including front and back sloping top walls joined together at a top transversal seal, and a pair of side top walls connecting respective lateral edges of said front and back sloping top walls, each of said side top walls being obtained by folding a respective portion of the sheet packaging material along predetermined crease lines delimiting a number of panels, wherein said crease lines are determined among a plurality of possible crease lines designed so as the forming of the side top walls is performed by rotations of said panels as rigid bodies about their respective crease lines.  
   
   
       2 . A package as claimed in  claim 1 , wherein the crease lines for forming the side top walls are obtained by choosing at least a value of a top angle formed, along each side top wall, between opposite edges thereof converging to said top transversal seal, and a value of the length of one of said front and back sloping top walls along a direction crosswise to said top transversal seal.  
   
   
       3 . A package as claimed in  claim 1 , wherein the package is obtained from an intermediate pack having a prismatic main portion and at least a tapered end portion delimited by said top transversal seal, defining said front and back sloping top walls and provided with opposite protruding lateral flaps designed to be folded out of a package top volume available for the food product for obtaining said side top walls.  
   
   
       4 . A package as claimed in  claim 3 , wherein each of said lateral flaps has one side adjacent to one of said front and back sloping top walls and another side formed by a relative end portion of said top transversal seal and positioned adjacent to another of said front and back sloping top walls.  
   
   
       5 . A method for dimensioning a gable-top package for pourable food products obtained by folding and sealing a sheet packaging material, said package comprising a gabled top portion including front and back sloping top walls joined together at a top transversal seal, and a pair of side top walls connecting respective lateral edges of said front and back sloping top walls and obtained by folding respective portions of the sheet packaging material along predetermined crease lines delimiting a number of panels, said method comprising determining a position and extension of said crease lines so that forming of the side top walls is performed by rotations of said panels as rigid bodies about their respective crease lines.  
   
   
       6 . A method as claimed in  claim 5 , wherein said determining of the position and extension of said crease lines is performed by choosing desired values of at least a top angle formed, along each side top wall, between opposite edges thereof converging to said top transversal seal, and a length of one of said front and back sloping top walls along a direction crosswise to said top transversal seal.  
   
   
       7 . A method as claimed in  claim 6 , wherein said determining of the position and extension of said crease lines comprises designing, in a portion of said sheet packaging material destined to form the gabled top portion of the package: 
 a first transversal crease line ( 31 ) delimiting said top transversal seal;    a second transversal crease line forming horizontal corners of said gabled top portion and positioned at a distance from said first transversal crease line equal to said chosen length;    a number of longitudinal crease lines delimiting, together with said first and second transversal crease lines, a couple of first zones defining said side top walls and a couple of second zones defining said front and back sloping top walls, said longitudinal crease lines forming with respective portions of said second transversal crease line external to said first zones, respective angles equal to said chosen top angle; and    a number of internal crease lines, which are located within each said first zone and whose orientation is determined by geometric relations obtained by considering that the panels have to be rotated as rigid bodies during the forming of the gabled top portion.    
   
   
       8 . A method as claimed in  claim 7 , wherein said internal crease lines comprise, for each said first zone, a couple of first inclined crease lines joined at said first transversal crease line and delimiting an isosceles triangle with said second transversal crease line, wherein the designing of said internal crease lines in each first zone comprises calculating an angle formed by each first inclined crease line with a portion of said second transversal crease line defining a side of said isosceles triangle, through the formula:  
     
       
         
           
             
               β 
               = 
               
                 arc 
                 ⁢ 
                 
                     
                 
                 ⁢ 
                 
                   tg 
                   ⁡ 
                   
                     ( 
                     
                       1 
                       
                         c 
                         / 
                         2 
                       
                     
                     ) 
                   
                 
               
             
             , 
           
         
       
     
     wherein c references a width of the package to be formed.  
   
   
       9 . A method as claimed in  claim 8 , wherein said internal crease lines comprise, for each said first zone, three second inclined crease lines extending from an intermediate point located within said isosceles triangle to respective vertex thereof, wherein the designing of said internal crease lines comprises calculating an angle formed by said second inclined crease lines with respective said first inclined crease lines through the formula:  
     
       
         
           
             
               β 
               2 
             
             = 
             
               
                 β 
                 - 
                 
                   ( 
                   
                     
                       θ 
                       1 
                     
                     - 
                     θ 
                   
                   ) 
                 
               
               2 
             
           
         
       
     
     wherein θ references an angle formed between each longitudinal crease line and an adjacent first inclined crease line, whilst θ i  references an angle formed by each longitudinal crease line with a portion of said second transversal crease line defining a side of said isosceles triangle, after folding of the gabled top portion has been completed.  
   
   
       10 . A method as claimed in  claim 9 , wherein said internal crease lines comprise, for each said first zone, a third inclined crease line ( 65 ;  66 ) extending from said intermediate point to said first transversal crease line, intersecting one of said first inclined crease lines and divided by said one of said first inclined crease lines into a first and a second portion forming therebetween angles different from 180° and located outside and inside said isosceles triangle, respectively, wherein said designing of said internal crease lines comprises calculating an angle formed by said first portion of said third inclined crease line with the portion of said first transversal crease line located inside each said first zone, through the formula:  
     
       
         
           
             
               γ 
               = 
               
                 
                   α 
                   - 
                   
                     ( 
                     
                       
                         2 
                         ⁢ 
                         
                             
                         
                         ⁢ 
                         arc 
                         ⁢ 
                         
                             
                         
                         ⁢ 
                         
                           sen 
                           ⁡ 
                           
                             ( 
                             
                               
                                 c 
                                 / 
                                 2 
                               
                               
                                 1 
                                 1 
                               
                             
                             ) 
                           
                         
                       
                       - 
                       α 
                     
                     ) 
                   
                 
                 2 
               
             
             , 
           
         
       
     
     wherein l 1  references a length of longitudinal crease lines.  
   
   
       11 . A sheet packaging material adapted to be folded along predetermined crease lines and sealed for producing a gable-top package for pourable food products, wherein said crease lines are dimensioned according to the method as claimed in  claim 5 .  
   
   
       12 . A sheet packaging material adapted to be folded along predetermined crease lines and sealed for producing a gable-top package for pourable food products, wherein said crease lines are dimensioned according to the method as claimed in  claim 6 .  
   
   
       13 . A sheet packaging material adapted to be folded along predetermined crease lines and sealed for producing a gable-top package for pourable food products, wherein said crease lines are dimensioned according to the method as claimed in  claim 7 .  
   
   
       14 . A sheet packaging material adapted to be folded along predetermined crease lines and sealed for producing a gable-top package for pourable food products, wherein said crease lines are dimensioned according to the method as claimed in  claim 8 .  
   
   
       15 . A sheet packaging material adapted to be folded along predetermined crease lines and sealed for producing a gable-top package for pourable food products, wherein said crease lines are dimensioned according to the method as claimed in  claim 9 .  
   
   
       16 . A sheet packaging material adapted to be folded along predetermined crease lines and sealed for producing a gable-top package for pourable food products, wherein said crease lines are dimensioned according to the method as claimed in  claim 10.