Separating and folding web materials cross-directionally

Abstract

The present invention relates to a novel equipment and a manufacturing process for separating a series of web pieces from an essentially continuous web and essentially concurrently forming an overfold along a cross-directionally extending fold line. The separating and overfolding may very advantageously be applied in the manufacturing of articles to be worn on the lower torso of a wearer, such as disposable absorbent articles, or disposable underwear.

1 . (canceled) 
     
     
         2 . (canceled) 
     
     
         3 . (canceled) 
     
     
         4 . (canceled) 
     
     
         5 . (canceled) 
     
     
         6 . (canceled) 
     
     
         7 . (canceled) 
     
     
         8 . (canceled) 
     
     
         9 . (canceled) 
     
     
         10 . (canceled) cm  11 . (canceled) 
     
     
         12 . (canceled) 
     
     
         13 . (canceled) 
     
     
         14 . (canceled) 
     
     
         15 . A method for forming a series (n, n+1, . . . ) of overfolded pieces of web material from an essentially endless web material, each piece comprising a first and a second end section and a middle section positioned there between and comprising a cross-directionally extending fold line such that said first and said second section are at least partially lying upon another,
 said method comprising the steps of
 a) providing an essentially continuous supply of a web material along a web path defining a downstream machine direction away from said web supply; 
 b) providing a folding and separating unit comprising
 b1) a web inlet; 
 b2) a folder web support means; 
 h3) a web holding means; 
 b4) a web separating means 
 
 wherein
 b5) said folder web support means is positioned downstream of said web inlet, separated by an inlet gap there from 
 
 and wherein
 b6) said web holding means is moveably mounted such that it can move around said folder web support means from a position downstream of said folder web support means to a position in said inlet gap; 
 
 c) feeding a leading end of said essentially continuous web from said web supply through said web inlet over said inlet gap towards said folder web support means; 
 d) affixing said leading end of said essentially continuous web temporarily on said folder web support means and moving it machine directionally downstream; 
 e) adjusting the movement of said web holding means around said folder web support means such that said web holding means is positioned downstream of said folder web support means when said leading end of said essentially continuous web is released from said folder web support means whilst continuing to move along the machine direction downstream, such that said leading end contacts said web holding means and is temporarily affixed thereto; 
 f) moving said web holding means with said leading end affixed thereto towards said inlet gap, thereby forming a cross-directional overfold in said web; 
 g) essentially concurrently
 g1) positioning said leading end over a downstream region of said web and 
 g2) separating a piece of web material from said essentially continuous web, and 
 g3) releasing said piece of web material from said web holding means, 
 
 such that
 g4) a new leading end (n+1) is formed and 
 g5) the original leading end (n) now forms the first end section of said piece of web material overlying said second end of said web piece formed by the trailing end as being separated from said new leading end (n+1), whilst the cross-directional fold is positioned in the middle section thereof; 
 h) removing said web holding means from said inlet gap and allowing said new leading end (n+1) to move through said inlet gap to said folder web support means; 
 
 and repeating steps d) to h), whereby in course of step d) said overfolded piece of web material (n) is removed from said folding and separating unit. 
   
     
     
         16 . A method according to  claim 15 , wherein said separating means is selected from the group consisting of
 a knife blade counteracting with another blade;   a knife blade counteracting against an anvil;   a water jet system;   a radiation technique;   sonic cutting.   
     
     
         17 . A method according to  claims 15 , wherein said web separating means and said web holding means are essentially unitary or operatively connected to each other such that both travel around said web folding means according to steps e), f) and h). 
     
     
         18 . A method according to  claims 15 , wherein said separating means is a rotating knife blade counteracting with a counter-blade,
 wherein said rotating knife blade is rotating around an axis essentially parallel to the machine direction of said unit;   and wherein said counter-blade is positioned in said web inlet.   
     
     
         19 . A method according to  claim 15 , wherein said leading end of said web is temporarily attached to said web holding means by one or more attachment means selected from the group consisting of vacuum, mechanical engagement of the “hook-loop-type”, mechanical engagement by protruding pins. 
     
     
         20 . A method according to  claim 15 , wherein said overfolding of said web is executed such that cross-directionally extending edges of the first and said second section of said piece of web material exhibit a machine-directional off-set of less than 25 mm. 
     
     
         21 . A method according to  claim 15 , wherein the distance, that a trailing end edge of a second section of a piece of web material travels before it is positioned adjacent to the first section of said piece of web material is less than 25 mm along the machine direction. 
     
     
         22 . A method according to  claim 15 , further comprising one or more of the following steps:
 z) providing a first web transfer means and transferring said essentially continuous web to said folding and separation unit;
 y) providing a second web transfer means and removing said overfolded pieces of said web material downstream of said folder web support means; 
 x) providing a third web transfer means and removing said overfolded pieces of said web material, whereby said third web transfer means is adapted to make a first contact to said pieces of said web material whilst these are in contact with said folder web support means; 
 w) providing a bonding means downstream of said holding web support means and bonding overlying portions of said piece of web material; 
 v) varying the speed of movement of said web holding means for adjusting the predetermined overall length of the piece of web material; 
 u) providing a folding means to fold pieces of a fastening means, e.g. a hook/loop type fastener which is fixed to and extending over the lateral side margins of said first or second end section of the piece of web material, around a longitudinal fold line such that it engages with the respective other end section. 
   
     
     
         23 . An apparatus
 for forming a series (a, n+1, . . . ) of overfolded pieces of web material from an essentially endless web material supplied by web supply means, each piece comprising a first and a second end section and a middle section positioned there between, thereby defining the longitudinal direction of said pieces, and comprising a cross-directionally extending fold line such that said first and said second section are at least partially lying upon another,   said apparatus comprising a folding and separating unit, said folding and separating unit being positioned downstream of said web supply unit and comprising
 1) a web inlet for feeding an essentially continuous web material to said folding and separating unit; 
 2) a folder web support means positioned downstream of said web inlet, expanding along the machine direction (x-direction) and exhibiting a cross-machine extension (y-direction) aligned with the cross-direction of said piece of web material, and a height (z-directional.) extension; 
 3) a web holding means adapted to receive and temporarily hold a section of said web material; 
 4) a web separating means adapted to separate a piece of web material from said essentially continuous web material; 
   wherein said web holding means is moveably mounted to allow cyclic movement around said folder web support means with said web being temporarily attached thereto along a movement path forming an essentially x-z-directionally extending plane for positioning said first section of said web material piece onto said second section of said web material and for forming a cross-directional fold in said middle section of said web material or piece thereof,   wherein said web separating means is cooperatively connected to said web holding means or has its cyclic operation controlled by or is operated in registry with the cyclic movement of said web holding means.   
     
     
         24 . An apparatus according to  claim 23 , wherein said web support means and web holding unit are set in motion by one or more drive systems. 
     
     
         25 . An apparatus according to  claim 24 , wherein said folder web support means is operated at constant speed whilst the web holding unit travels at a cyclic speed pattern, preferably a sinusoidal pattern around said folder web support means. 
     
     
         26 . An apparatus according to any of  claims 23 , wherein a gap formed between said web inlet and said folder web support is smaller than 20 cm. 
     
     
         27 . An apparatus according to  claim 23 , wherein said separating means is selected from the group consisting of
 a knife blade counteracting with another blade;   a knife blade counteracting against an anvil;   a water jet system;   a radiation technique;   sonic cuffing.   
     
     
         28 . An apparatus according to  claim 23 , wherein said separating unit comprises a cross-directionally extending knife blade rotatably mounted to rotate around an axis of rotation which is essentially parallel to the machine direction. 
     
     
         29 . A method according to  claim 15 , wherein in step b6) said movement of said web holding means is preferably rotational around an axis perpendicular to said machine direction. 
     
     
         30 . A method according to  claim 15 , wherein in step e) said affixing of said leading end to said web holding means is by actuating a holding force. 
     
     
         31 . A method according to  claim 20 , wherein the cross-directionally extending edges of the first and said second section of said piece of web material exhibit a machine-directional off-set of less than 2 mm. 
     
     
         32 . A method according to  claim 31  wherein the cross-directionally extending edges of the first and said second section of said piece of web material exhibit a machine-directional of which is essentially zero. 
     
     
         33 . A method according to  claim 21 , wherein the distance, that a trailing end edge of a second section of a piece of web material travels before it is positioned adjacent to the first section of said piece of web material is less than 5 mm, more preferably less than 5 mm along the machine direction. 
     
     
         34 . A method according to  claim 33 , wherein the distance, that a trailing end edge of a second section of a piece of web material travels before it is positioned adjacent to the first section of said piece of web material is less than 2 mm along the machine direction. 
     
     
         35 . A method according to  claim 22 , wherein in step x) of providing a third web transfer means said third web transfer means is movable relative to said folder web support means. 
     
     
         36 . A method according to  claim 22 , wherein in step w) of providing a bonding means selected from the group consisting of adhesive application, connecting of mechanical fastening elements of the hook and loop type, heat or fusion bonding comprising ultra sonic bonding. 
     
     
         37 . A method according to  claim 22 , wherein in step w) of providing a bonding means, said bonding means is cooperatively connected with at least one of said second or third web transfer means. 
     
     
         38 . An apparatus according to  claim 23 , wherein said folder web support means is a vacuum belt system. 
     
     
         39 . An apparatus according to  claim 23 , wherein said web holding means is rotatably mounted. 
     
     
         40 . An apparatus according to  claim 23 , wherein said movement path forming an essentially x-z-directionally extending plane, is selected from the group consisting of a circular, an elliptic and an oval path. 
     
     
         41 . An apparatus according to  claim 24 , wherein said one or more drive system's is/are selected from the group consisting of drive belts, gear wheels, electrical drive motors. 
     
     
         42 . An apparatus according to  claim 26 , wherein said gap formed between said web inlet and said folder web support is smaller than 10 cm. 
     
     
         43 . An apparatus according to  claim 42 , wherein said gap formed between said web inlet and said folder web support is smaller than 5 cm.