Dual head straw wrapper

Abstract

An improved method and apparatus for individually wrapping drinking straws applies a web of wrapping material to sequentially supplied straws while providing separately: (i) a crimping station for the wrapping material which secures it about the straws by providing longitudinal and transverse crimps and (ii) a cutting station for separating the wrapped straws. The discrete locations of the crimping and cutting stations enables faster and more reliable production by separating operations, which reduces the amount of mechanical interaction between dies at a single location, thereby reducing die bounce. Speed increases of 15-20 percent are readily achieved.

1 . In an apparatus for individually wrapping drinking straws, the combination comprising: 
 (a) means for supplying a continuous web of packaging material shaped around sequentially supplied straws moving in a production direction such that longitudinal edges of the shaped packaging material are aligned with each other;    (b) a crimping station at a first location for wrapping a sequentially supplied straw including means for crimping a seam along the aligned longitudinal edges of the shaped web material and means for crimping a seam transverse to the longitudinal edges of web material to form a closed sleeve with a crimped longitudinal fin and two transverse fins such that a closed crimped sleeve is formed around the straw and the straw remains attached to the continuous web;    (c) a cutting station at a second location with means for cutting the transverse crimped seams between adjacent ones of the sequentially supplied and wrapped straws;    (d) means for advancing the wrapped straw from the crimping station to the cutting station while the closed sleeve remains attached to the continuous web of packaging material; and    (e) means for synchronizing the crimping and cutting stations;    wherein the crimping and cutting stations operate in concert at discrete sequential locations along a production direction.    
     
     
         2 . The combination according to  claim 1 , wherein the cutting station includes a pair of opposed cutting wheels, one of the wheels having a cutting member for severing the crimped transverse ends between adjacent closed sleeves.  
     
     
         3 . The combination according to  claim 2 , wherein the cutting wheels include mutually engaged gears and the mutually engaged gears are a metal gear and a plastic gear.  
     
     
         4 . The combination according to  claim 1 , wherein the means for advancing the wrapped straw includes: 
 (f) an intermediate drive roller positioned between the crimping station and the cutting station; and    (g) an intermediate support roller opposing the intermediate drive roller adapted to cooperate therewith for sequentially feeding the closed sleeved straws from the crimping station to the cutting station.    
     
     
         5 . The combination according to  claim 1 , wherein the crimping station includes a set of rotatable opposed matching crimping dies with splines for crimping the aligned longitudinal edges of the shaped web material in a longitudinal feed direction of the sequentially supplied straws and with splines for crimping the shaped web material transverse to the longitudinal feed direction of the web material.  
     
     
         6 . The combination according to  claim 5 , further comprising: 
 (h) a first timing belt coupling the set of crimping dies to the intermediate drive roller, thereby coordinating the timing of straw feed from the crimping station through the drive and support rollers; and    (i) a second timing belt connecting the crimping station to cutting station, thereby coordinating the timing of straw feed through the crimping station with the timing of straw feed through the cutting station.    
     
     
         7 . The combination according to  claim 6 , further comprising: 
 a guide plate at an inlet end of the cutting station, the guide plate separating the web material from the gears of the cutting station.    
     
     
         8 . The combination according to  claim 2 , wherein the mating cutting wheels include channels with an inwardly arcuate shape formed in each outer peripheral surface, such that an outer circular surface of the closed sleeved straw will pass through aligned mating cutting wheels, one of the mating cutting wheels including a cutting member in a defined portion of the outer peripheral surface thereof and synchronized to cut against the opposing cutting wheel at the transverse crimp of the closed sleeve.  
     
     
         9 . The combination according to  claim 8 , wherein the inwardly arcuate channel of the cutting wheels correspond in length to a length of an individual straw.  
     
     
         10 . The combination according to  claim 8 , wherein the cutting member interrupts the inwardly arcuate shape of the die cutting wheels intermediate adjacent sequential closed sleeved straws to sever a crimped transverse seam.  
     
     
         11 . The combination according to  claim 8 , wherein the cutting member of the cutting station includes a cutting blade at an outer surface of one of the opposed mating die cutting wheels for performing a transverse cut within the crimped seam area against an anvil of the opposing die cutting wheel and separating adjacent wrapped straws.  
     
     
         12 . In an apparatus for individually wrapping drinking straws, the combination comprising: 
 (a) means for supplying a continuous web of wrapping material shaped around sequentially supplied straws moving in a production direction such that longitudinal edges of the shaped wrapping material are aligned with each other;    (b) a crimping station at a first location including a pair of opposed rotatable and matched crimping dies provided with circumferential channels and first and second sets of crimping splines, 
 (i) the first set of crimping splines being disposed over the circumference of the crimping die and being adapted to provide a longitudinal crimped fin along the longitudinal edges of the wrapping material which is thereby secured around the straw over the length of the straw,  
 (ii) the second set of crimping splines extending over a distance less than the distance between sequentially supplied straws and being adapted to provide a transverse crimp between sequentially supplied straws such that each straw is contained within a crimped sleeve containing the straw,  
   (c) the sleeve being thus closed along the longitudinal as well as transverse directions,    (d) a cutting station disposed at a second location including a pair of opposed cutting wheels, each of the wheels having a channel adapted to receive a wrapped straw therebetween, the wheels also including means for severing wrapped straws along the transverse crimped fins therebetween to produce individually wrapped straws;    (e) a conveying station including a pair of opposed drive rollers disposed at a third location intermediate the crimping station and the cutting station, the drive rollers being operable to advance a wrapped straw attached to the web between the crimping station and the cutting station; and    (f) means for synchronizing the crimping station, the conveying station and the cutting station.    
     
     
         13 . The combination according to  claim 12 , wherein the crimping station, the conveying station and the cutting station are disposed within about the length of a wrapped straw.  
     
     
         14 . The combination according to  claim 12 , wherein the crimping dies are biased toward each other.  
     
     
         15 . The combination according to  claim 12 , wherein the cutting wheels are biased toward each other.  
     
     
         16 . The combination according to  claim 12 , wherein the crimping station, conveying station and cutting station are linked to a common drive.  
     
     
         17 . The combination according to  claim 16 , wherein the crimping station, conveying station and cutting station are linked by way of a plurality of timing belts.  
     
     
         18 . A method for individually wrapping drinking straws comprising the steps of: 
 (a) supplying a continuous web of packaging material to a web shaping station;    (b) shaping the continuous web around sequentially supplied straws moving in a production direction such that longitudinal edges of the shaped material are aligned;    (c) crimping, at a first location, the aligned longitudinal edges of the shaped web material to form a longitudinal seam and crimping a seam transverse to the longitudinal edges of the shaped web material to form a closed sleeve with crimped longitudinal and transverse fins such that the closed sleeve remains attached to the continuous web;    (d) transporting the combined straw and surrounding closed sleeve out of the crimping station wherein the closed sleeve remains attached to the continuous web;    (e) delivering the combined straw and surrounding closed sleeve to a cutting station at a second location while the sleeve remains a continuous closed sleeve; and    (f) cutting, at the second location, the crimped end seam between adjacent ones of the sequentially supplied and closed sleeved straws within the crimped area of the end seam thereby separating adjacent wrapped straws; and    (g) synchronizing the crimping and cutting steps    (h) wherein the crimping station and cutting station operate in concert but at discrete sequential locations along a production direction.    
     
     
         19 . The method according to  claim 18 , wherein the steps of transporting and delivering include: 
 (i) positioning a drive roller intermediate the crimping station and the cutting station; and    (j) providing a support roller mating with the intermediate drive roller for sequentially feeding the straws from the crimping station to the cutting station.    
     
     
         20 . The method according to  claim 18 , wherein the step of crimping is carried out between a pair of rotatable crimping dies, each having first and second spline sets, wherein (i) the first set of crimping splines being disposed over the circumference of the crimping die and being adapted to provide a longitudinal crimped fin along the longitudinal edges of the wrapping material which is thereby secured around the straw over the length of the straw and (ii) the second set of crimping splines extending over a distance less than the distance between sequentially supplied straws and being adapted to provide a transverse crimp between sequentially supplied straws such that each straw is contained within a crimped sleeve containing the straw.