Methods of manufacturing slider-operated string-zippered bags on VFFS machine

Abstract

A method of manufacture comprising the following steps: (a) guiding a web material in a machine direction through a vertical form-fill-seal (VFFS) machine with a portion or portions of the web material being wrapped around a tube; (b) joining first and second flangeless zipper strips to first and second portions of the web material that do not form part of the portion or portions of the web material that are wrapped around the tube; (c) inserting a slider on the first and second flangeless zipper strips joined to the web material; (d) cross sealing the web material at a location downstream from the tube; and (e) dropping product through the tube and onto the most recently formed cross seal.

1 . A method of manufacture comprising the following steps: 
 (a) guiding a web material in a machine direction through a vertical form-fill-seal (VFFS) machine with a portion or portions of said web material being wrapped around a tube;    (b) joining first and second flangeless zipper strips to first and second portions of said web material that do not form part of said portion or portions of said web material that are wrapped around a fill tube of said VFFS machine;    (c) inserting a slider on said first and second flangeless zipper strips joined to said web material;    (d) cross sealing said web material at a location downstream from said fill tube; and    (e) dropping product through said fill tube and onto the most recently formed cross seal.    
   
   
       2 . The method as recited in  claim 1 , wherein steps (b) and (c) are performed at stations upstream of said tube, further comprising the step of guiding said slider in a channel in a forming collar of said VFFS machine as said web material advances.  
   
   
       3 . The method as recited in  claim 1 , wherein steps (b) and (c) are performed at stations adjacent said tube.  
   
   
       4 . The method as recited in  claim 1 , wherein step (b) is performed at stations upstream of said tube and step (c) is performed at a station adjacent said tube.  
   
   
       5 . The method as recited in  claim 1 , wherein said first flangeless zipper strip is joined to said web material at a station upstream of said tube and said second flangeless zipper strip is joined to said web material at a station adjacent said tube.  
   
   
       6 . The method as recited in  claim 3 , further comprising the steps of: 
 guiding a portion of said web material to form a loop, said looped portion comprising said first and second portions to which said first and second flangeless zipper strips are respectively joined;    aligning said first and second flangeless zipper strips with each other; and    guiding said first and second flangeless zipper strips to positions whereat said aligned first and second flangeless zipper strips are disposed between said first and second portions of said web material.    
   
   
       7 . The method as recited in  claim 6 , further comprising the steps of: 
 guiding first and second marginal portions of said web material into mutually confronting relationship; and    joining said first and second marginal portions to each other.    
   
   
       8 . The method as recited in  claim 6 , further comprising the steps of cutting off a third portion of said web material that lies between said first and second portions of said web material and forms part of said loop.  
   
   
       9 . The method as recited in  claim 3 , further comprising the steps of: 
 guiding a portion of said web material to form a gusset, said gusseted portion comprising said first and second portions to which said first and second flangeless zipper strips are respectively joined;    aligning said first and second flangeless zipper strips with each other; and    guiding said first and second flangeless zipper strips to positions whereat said aligned first and second flangeless zipper strips are disposed between said first and second portions of said web material.    
   
   
       10 . The method as recited in  claim 9 , further comprising the steps of: 
 guiding first and second marginal portions of said web material into mutually confronting relationship; and    joining said first and second marginal portions to each other.    
   
   
       11 . The method as recited in  claim 9 , further comprising the steps of cutting off first and second folded portions of said web material disposed at a mouth of said gusset on opposite sides of said first and second flangeless zipper strips.  
   
   
       12 . The method as recited in  claim 1 , wherein said first and second portions of said web material are at or near respective lateral edges of said web material.  
   
   
       13 . A method of automatically manufacturing bags fitted with a slider-operated string zipper, comprising the following steps: 
 (a) intermittently advancing a web along a pathway that partly encircles a tube, whereby after each advancement, first and second portions of said web are wrapped around respective portions of a tube having an axis, while third and fourth portions of said web extend generally radially outward from said tube;    (b) during each dwell time, joining respective sections of first and second flangeless zipper strips to said third and fourth portions of said web while said first and second portions of said web are wrapped around said respective portions of said tube, thereby forming a zipper-web assembly;    (c) during each dwell time, inserting a slider on said first and second flangeless zipper strips respectively joined to said third and fourth web portions;    (d) during each dwell time and after step (b) has been performed, cross sealing said web in a first transverse region at an elevation below an outlet end of said tube;    (e) during each dwell time, dropping product down said tube and onto the most recently cross-sealed portion of said web; and    (f) during each dwell time, cutting said zipper and said web along a transverse line that intersects a respective cross-sealed region, thereby severing a finished bag from the zipper-web assembly.    
   
   
       14 . The method as recited in  claim 13 , wherein said web has first and second lateral edges that are parallel to each other when said web is flat, said third portion of said web being adjacent or near said first lateral edge, and said fourth portion being adjacent or near said second lateral edge.  
   
   
       15 . The method as recited in  claim 14 , further comprising the step, performed during each dwell time, of trimming at least some of the excess web material that extends from said third portion of said web to said first lateral edge and at least some of the excess web material that extends from said fourth portion of said web to said second lateral edge.  
   
   
       16 . The method as recited in  claim 13 , further comprising the following steps, performed before said respective sections of said first and second flangeless zipper strips are joined to said third and fourth portions of said web respectively: 
 interlocking said respective sections of said first and second flangeless zipper strips together;    guiding said interlocked respective sections of said first and second flangeless zipper strips to a position outside said tube and parallel to said tube axis; and    forming a gusset in said web, said third and fourth portions of said web forming respective mutually confronting portions of said gusset and being disposed on opposite sides of said interlocked respective sections of said first and second flangeless zipper strips during joining of said respective sections of said first and second flangeless zipper strips to said third and fourth portions of said web respectively.    
   
   
       17 . The method as recited in  claim 16 , further comprising the step, performed during each dwell time, of trimming at least some of the excess web material that extends beyond said interlocked respective sections of said first and second flangeless zipper strips in a direction away from said tube.  
   
   
       18 . The method as recited in  claim 16 , wherein said web has first and second lateral edges that are parallel to each other when said web is flat, further comprising the following steps: 
 guiding first and second marginal portions of said web into mutually confronting positions, said first marginal portion being bounded on one side by said first lateral edge and said second marginal portion being bounded on one side by said second lateral edge; and    joining said first and second marginal portions of said web together.    
   
   
       19 . The method as recited in  claim 13 , further comprising the following steps, performed before said respective sections of said first and second flangeless zipper strips are joined to said third and fourth portions of said web respectively: 
 interlocking said respective sections of said first and second flangeless zipper strips together;    guiding said interlocked respective sections of said first and second flangeless zipper strips to a position outside said tube and parallel to said tube axis; and    forming a loop in said web, said third and fourth portions of said web forming respective mutually confronting portions of said loop and being disposed on opposite sides of said interlocked respective sections of said first and second flangeless zipper strips during joining of said respective sections of said first and second flangeless zipper strips to said third and fourth portions of said web respectively.    
   
   
       20 . The method as recited in  claim 19 , further comprising the step, performed during each dwell time, of trimming at least a portion of said loop.  
   
   
       21 . The method as recited in  claim 19 , wherein said web has first and second lateral edges that are parallel to each other when said web is flat, further comprising the following steps: 
 guiding first and second marginal portions of said web into mutually confronting positions, said first marginal portion being bounded on one side by said first lateral edge and said second marginal portion being bounded on one side by said second lateral edge; and    joining said first and second marginal portions of said web together.    
   
   
       22 . A method of manufacture comprising the following steps: 
 (a) guiding a length of web material, having mutually parallel first and second lateral edges when said web material is flat, such that a major portion of said length of web material is wrapped around a tube having an axis, and first and second portions adjacent or near said first and second lateral edges respectively of said length of web material extend in mutually confronting relationship outside said tube, separated by a gap;    (b) guiding a length of string zipper comprising interlocked first and second flangeless zipper strips to a position outside said tube and parallel to said tube axis, said length of string zipper being disposed in said gap between said first and second portions of said length of web material;    (c) joining said length of string zipper to said length of web material while said major portion of said length of web material is wrapped around said tube, thereby forming a zipper/web assembly, said first flangeless zipper strip being joined to said first portion and said second flangeless zipper strip being joined to said second portion; and    (d) inserting a slider onto said zipper/web assembly while said major portion of said length of web material is wrapped around said tube.    
   
   
       23 . The method as recited in  claim 22 , further comprising the following steps: 
 (e) moving said length of web material to a position whereat said major portion of said length of web material is not wrapped around said tube;    (f) cross sealing said zipper-web assembly in first and second transverse regions that are spaced apart while said major portion of said length of web material is not wrapped around said tube;    (g) after said first transverse region has been cross sealed and before said second transverse region has been cross sealed, dropping product down said tube and onto said cross-sealed web in said first transverse region; and    (h) cutting said zipper-web assembly in each of said first and second transverse regions.    
   
   
       24 . The method as recited in  claim 22 , further comprising the step of trimming at least some of the excess web material that extends from said first portion of said web to said first lateral edge and at least some of the excess web material that extends from said second portion of said web to said second lateral edge.  
   
   
       25 . A method of manufacture comprising the following steps: 
 (a) guiding a length of web material, having mutually parallel first and second lateral edges when said web material is flat, such that: (i) first and second portions of said length of web material are wrapped around respective portions of a tube, (ii) first and second marginal portions adjacent said first and second lateral edges respectively of said length of web material project generally outward and away from said tube in mutually confronting relationship, and (iii) said first and second portions are connected by a loop having mutually opposing first and second walls separated by a gap;    (b) guiding a length of string zipper comprising interlocked first and second flangeless zipper strips to a position outside said tube and parallel to said tube axis, said length of string zipper being disposed in said gap between said first and second walls of said loop;    (c) joining said length of string zipper to said length of web material while said first and second portions of said length of web material are wrapped around respective portions of said tube, thereby forming a zipper/web assembly, said first flangeless zipper strip being joined to said first portion and said second flangeless zipper strip being joined to said second portion;    (d) cuffing off a portion of said loop beyond said string zipper; and    (e) after step (d), inserting a slider onto said zipper/web assembly while said first and second portions of said length of web material are wrapped around respective portions of said tube.    
   
   
       26 . A method of manufacture comprising the following steps: 
 (a) guiding a length of web material, having mutually parallel first and second lateral edges when said web material is flat, such that: (i) first and second portions of said length of web material are wrapped around respective portions of a tube, (ii) first and second marginal portions adjacent said first and second lateral edges respectively of said length of web material project generally outward and away from said tube in mutually confronting relationship, and (iii) said first and second portions are connected by a folded portion having an M-shaped profile with mutually opposing first and second interior walls separated by a gap;    (b) guiding a length of string zipper comprising interlocked first and second flangeless zipper strips to a position outside said tube and parallel to said tube axis, said length of string zipper being disposed in said gap between said first and second interior walls of said folded portion;    (c) joining said length of string zipper to said length of web material while said first and second portions of said length of web material are wrapped around respective portions of said tube, thereby forming a zipper/web assembly, said first flangeless zipper strip being joined to said first portion and said second flangeless zipper strip being joined to said second portion; and    (d) inserting a slider onto said zipper/web assembly while said first and second portions of said length of web material are wrapped around respective portions of said tube.    
   
   
       27 . A method of manufacture comprising the following steps: 
 (a) guiding a web material in a machine direction through a vertical form-fill-seal (VFFS) machine;    (b) joining a string zipper to said web material upstream of said VFFS machine;    (c) inserting a slider over said string zipper and portions of said joined web material at a location adjacent a tube of said VFFS machine;    (d) cross sealing said web material at an elevation below said tube; and    (e) dropping product through said tube and onto the most recently formed cross seal.    
   
   
       28 . The method as recited in  claim 27 , wherein step (b) comprises joining a first flangeless zipper strip of said string zipper to said web material upstream of said VFFS machine and joining a second flangeless zipper strip of said string zipper to said web material adjacent said tube.  
   
   
       29 . The method as recited in  claim 27 , wherein step (b) comprises joining a first flangeless zipper strip of said string zipper to a first portion of said web material upstream of said VFFS machine and joining a second flangeless zipper strip of said string zipper to a second portion of said web material upstream of said VFFS machine.  
   
   
       30 . A method of manufacture comprising the following steps: 
 (a) guiding a web material in a machine direction through a vertical form-fill-seal (VFFS) machine with portions of said web material being wrapped around respective portions of a tube of said VFFS machine;    (b) joining said web material to two sides of a string zipper to form a web/string zipper assembly, said joining step being performed at locations upstream of said VFFS machine;    (c) removing at least a portion of the web material suspended between the zones of web/zipper joinder at a location upstream of said VFFS machine, but downstream of the locations where step (b) is performed;    (d) inserting a slider on said string zipper at a location upstream of said VFFS machine, but downstream from the locations where step (b) is performed;    (e) cross sealing said web material at a location downstream from said tube; and    (f) dropping product through said tube and onto the most recently formed cross seal.    
   
   
       31 . The method as recited in  claim 30 , further comprising the step of guiding said string zipper and inserted slider through a channel in a forming collar of said VFFS machine as said web/string zipper assembly advances in said machine direction through a gap between said tube and said forming collar.  
   
   
       32 . The method as recited in  claim 1 , further comprising the step of guiding and turning said string zipper and said inserted slider 90 degrees between entering and exiting a forming collar.