CA1308969C - Method of and apparatus for controlling application of glue to defined areas - Google Patents

Abstract

METHOD OF AND APPARATUS FOR
CONTROLLING APPLICATION OF GLUE TO DEFINED AREAS

Abstract of the Disclosure Apparatus for applying adhesive onto flutes of single facers of corrugated media, so that the single facers may be adhered together and to a facing to form a composite web, comprises a plurality of adhesive applicator rolls, each for applying adhesive to the flutes of an associated one of the single facers. The actual speed of travel of the single facers passing across the applicator roll peripheries is sensed, and the rate of notation of each roll is independently and accurately controlled, in accordance with the sensed speed, to apply a desired amount of adhesive onto selected areas of the flutes. The independent accurate control over applicator roll speeds enables minimum amounts of adhesive to be applied onto the flutes of the individual single spacers, as determined by their configurations and consistencies, while still ensuring proper adhesion of the single facers one to the other and to the facing. Applying minimum amounts of adhesive onto the flutes reduces both the amount of adhesive required and moisture added to the single facers, so less heat is required to set the adhesive. In addition, minimizing moisture added to the single facers substantially eliminates warping of the composite web and "ribbing" on its outer surfaces, so the surfaces are very smooth and very high quality printing and graphics may be applied onto the surfaces.

Description

?$~9 B~ckground ot tbe Inventlon The present Inventlon relates lo a method ot and apparatu~ tor applying adheslve onto webs ot sheet materlal so that the webs m8y be adhered together, and in partlcular to such a method and apparatus In whlch the amount and location of adheslve applled onto tlutes of slngle tacers Is very accurately controlied.
Prlor machlnes for applylng adhe~lve onto the tlutes ot a plurallty ot slngle facers of corrugated cardboard medla, so that the slngle facers may be adhered In overlylng relatlon~hlp and to a taclng to torm a oheet of cardboard, use appllcator rolls for applylng adheslve onto the flutes, and one or more belts at a comblner bring the slngle tacer- Into overlylng ~nd adherlng relatlonshlp and pull the slngle facers across the appllcator roll~ and through the machlne. The comblner belts are supported on and moved by drums, and the appllcator roll~ are normally drlven by means of a dlrect drlve between one of the drums and the rolls.
Usually, one drum carrles a sprocket connected by a chaln to an input sprocket to a dlstrlbutor, and sprocket~ carrled by Indlvldual appllcator rolls are connected by chalns to an output sprocket trom the dlstrlbutor. Rotatlon ot the comblner drum theretore rotates the applIcator rolls, and the arrangement Is such that a predetermlned tl~ed mechanlcal relatlonshlp e~lsts between the speeds ot rotatlon ot the appllcator rolls and that ot the drum.
A dlsadvantage of prlor adheslve applylng machines ig that the ratlo between the speed ot rotation ot the comblner drum and the speeds ot rotatlon ot the appllcator roll- cannot readlly be changed. Because ot 13~

the dlrect drlve between the drum and roll~ vla chalns and sprockets, to change the ratlo of the speeds requlre~ the tedlous procedure of changlng the dlstrlbutor Input ~procket. However, changlng the di~trlbutor Input sprocket only ~erve- to change the ratlo ot the speeds between the drum and each roll by the same amount. It does not change the ratlo of the speeds between the drum and Indlvldual one~ of the rolls by selected amounts, ~Ince that may be accompllshed only by al80 changlng the sproc~ets on the roll~, and as appllcator roll sprocket~ cannot readlly be replaced, prlor practlce does not contemplate that they be changed. Instead, once selected the applicator roJI
sprockets are normally not changed except aJ msy be requlred for replacement due to wear, and they usually are selected so that Irrespectlve of the speed of rotation of the comblner drum, all of the appllcator roll perlpherles move at the same speed, so ch~nglng the dlstrlbutor Input ~procket only ~erve~ to unlformly change the speed of each pplIcator roll periphery.
The ratlonale behlnd rotatlng the appllcator rolls by a dlrect drlve between the roll- and a comblner belt drum 1~ to obtaln a direct correlallon between the perlpheral speed~ ot the rolls and the speed of travel of the ~Ingle facer~ as they are pulled across the roll-. The slngle facers are pulled acrosJ the roll perlpherles by the comblner belt~, whlch rlde on and are moved by the comblner drum, so It 1~ assumed that, Ideally, a known and dlrect relatlonshlp exl~ts between the speed ot travel of the slngle facer~ and the speed of rotatlon of the drum and, therefore, between the speed of the ~Ingle facer~ and the speeds of the roll 13~9~9 peripherles. However lhe assumptlon Ignores and the lechnlque cannot accounl for slippage Ihal occur- in pracllce between the bells on Ihe drum and Ihe siDgle facer~ on Ihe bells. UDUallY, Ihe dlslributor Input sprockel 1- seleoted to oblaln a predelermined relalionshlp belween slngle facer and applicator roll perlpherrl speeds ruch thal Ihe roll perlpherieJ move sllghlly slower than the slngle facer- Io obtaln a wiplng acllon acros~ the flutes but because Or Jl ippdge the relstlonshlp 1- Imposslble to malntaln.
Because ot Ihe Inablllty ~vlth prlor machlnes to accurately conlrol Ihe speeds of Ihe applIcator roll perlpherles wllh respect to the peed of travel of slngle facers moved acro6s Ihe perlpherles and lo independenlly and accuralely conlrol the slngle frcer/roll perlphery speed relallonshlp for each appllcator roll lo compenYale tor varlallons In flute conflgurallons and conslslencle- accordlng to convenllonal pracllce an e~cess of adheslve ls applied onto Ihe flules lo cnsure proper adheslon of Ihe Ingle facers one to Ihe olher desplle mlsplacemenl of adheslve on Ihe flules as a e-ult of varlalions In the speed relatlonshlp. Thls Is accompllshed by uslng appllcalor rolls that have ellher rmoolh or cellular perlpheral surfaces and by uslng a melerlng roll lo doclor adhesive plc~ed up by Ihe appllcalor rolls In a manner lo leave a film of adheslve of selecled Ihlci~ness on the perlpherles for transfer to the slngle facer flute-.
However waler comprlse- a ubslantlal portlon of the adheslve and In addlllon to wa-tlng adhe-lve consequence of transferrlni~ e~cess adheslve to Ihe flules 19 thal Ihe flules are e~cesslvely molslened.

13G~9~9 The adhesive must be drled In the comblner to sdhere lhe slngle facers together so the more molsture that Is applled onto the flute- the greater the heat energy requlrements to ~ct the adheslve. More Importan~ly excesslvely molstenlng the flutes results In warplng of lhe resultlng cardboard materlal and ~rlbblng~ on its outer fAcing or surtace whlch otten makes it very dlfflcult If not Imposslble to apply hlgh quallly prlnllng or graphlcs onto the ~urface.
Ob~ect- ot the Inventlon An ob~ect of the pre~ent Inventlon 1~ to provlde an Improved apparatu~ for and method of applylng adhesive onto the flutes ot a plurallty of slngle tacers of corrugeted medla where the actual speed of travel ol the slngle facers through the apparatus Is dlrectly ensed and used to independently control the rale ot rotatlon of Indlvidual one~ of a plurallly of adhesive appllcalor roll~ to control the amount and locallon of adhesive transferred onto the flutes.
Another ob~ect Is to provlde such an apparatus and melhod In whlch the ~rnsed speed of travel of the ~Ingle facers Is u~ed to varlably and Independenlly control the speed of rotatlon of each appllcator roll in order to electlvely apply more or le-s adheslve onto the tlp- the leadlng edges or the tralllng edges of the flutes of Indlvldual ones of the slngle facers.
A furlher obJect Is to provlde such an apparslus and melhod whereln control over appllcalor roll speeds of rolHtlon with respect to web travel speed ~Igniflcantly reduces the amount of adheslve requlred to properly adhere the slngle facers one to the other.

13~ 9 Yet another obiec~ 1~ Io provlde such an apparatus and method wherein, by v~rtue of the reduction In the amount of adheslve and theretore moislure applied onto the ilutes, warping ot the resultlng cardboard and ~Iribbinen on Its smoo~h outer surlace are substantially eliminnted.
Stlll another ob~ect is to provide such sn appQratus snd method, in which ~he slzes o~ oips between the appllcator rolls and assoaiated welght roll5, through which the single facers pass, i- automaticslly sensed and oontrolled.
Summary o- tbe Inventlon In accordance with the present Inventlon, apparatus or applytng adheJlve onto the tlutes o~ a plurallty ot -corrugated webs comprlses a plurallty of adheslve appllcator rolls; means tor transterrlng adheslve to perlpheries of said appllcator rolls; means for moving the webs In unlson and at the same speed of travel, such thet each web moves across the perIphery of an assoclaled one of sald appllcator rollis wlth its ~lues agalnst sald perlphery for transfer of adhesive from aid perlphery to the flutes; means for senslng the actual speed of travel of the ~ebs; and means responsive to the ~ensed actual speed of travel of the webs for rotatlng each Indlvldual appllcator roll at a rate ot rotatlon that Is Independent of the rate of rotatlon ot the other rolls and that Is varled as necessary to malntaln constant an Indlvldually selected and ad~ustable relatlonshlp between the perIpheral speed ot the roll and the ~ensed actual speed o- travel of the web~, desplte any varlatlons In the sensed actual speed of travel of the webs, to thereby control the amount and 13~ 9 locatlon ot adheslve applled onto the tlute~ of each Indivldual one of the web~.
The Inventlon also contemplales a method o-applylng adheJlve to tlutes ot a plurallty ot corrug~ted webs, comprlslng the steps ot transterrlng adhesive lo perlpherles ot a plurallty ot appllcator rolls; moving the webs in unison snd at the same speed ot travel, such that each web moveJ across the periphery ot an sssoclated one ot the appllcstor roll~ wlth Its tlutes agalnst the perlphery to transter adheslve trom the perlphery to the tlute~; senslng the actual ~peed ot travel ot the webs; and rotating each appllcator roll, In accordance wlth the sensed actual ~peed ot travel ot Ihe web~, at a rate ot rotatlon that 1~ Independent ot the rato ot rotatlon o~ the other appllcator rolls and that Is varled as necessary to malntaln constant an Indlvldually selected and ad3ustablc relatlonshlp between the perlpheral speed ot the roll and the sensed actual speed ot travel ot the webs, desplte any varlatlons In the sensed actual speed ot travel ot the webs, to thereby control the amount and location ot adheslvc applled onto the tlute~ ot each Indlvldual one ot the webs.
i~rlet Descrlptlon ot the Drawlngs Flg. 1 Is a schematlc slde vlew ot an adheslve applylng apparatu~ tor slngle tacers ot corrugated cardboard medla, embodying the teachlngs ot the present Inventlon;
Fig. 2 Is a slde vlew ot structure tor supporting a welght roll and controlllng the size ot a nlp between tho weli~ht roll and an associated adheslve appllcalor roll, and 13~

Plg. 3 18 a ~ide view of q doetor a~sembly tor meterlng Adhesive on ~n applicator roll.
Detalled Descrlptlon Flg. 1 Illustrates an apparatus, Indleated generally at 20, tor applylng adheslvo or glue onto flutes 22a-e of slnele racers or corrugated webs 24a-c of cardboard medla, and for plaelng the single faeers and a t~clng In overlylng relationshlp 80 that the same are adhered one to the other to form a eomposlte cardboard sheet 26. The actual speed ot travel of the cardboard sheet, and therefore ot the slngle racers, i8 contlnuously direetly sensed or monitored by means of a trletlon wheel 28 rldlng on an upper surtace ot the sheet. The wheel Is eoupled to a tachometer 30 that generate~ a slgnal having a value In accordance with sensed web speed and applle~ the slgnal to both a programmable mlcroproeessor 32 and a motor speed controller 34. The motor speed controller and mleroproeessor are Interconnected, snd the motor speed controller 1~ coupled to a plurallty of d.e. motors 36a-c, each ot whlch rotates a respectlve one ot a plurality of engraved or eellular ~urtaced adhesive appllcator roll~ 38a-c. ~rsoelated and deflnlng nlps wlth the applleator rolls are re~uectlve welght rolls 40a-c, and the electrle motors, along wlth the appllcator and welght roll~, are at an adheslve applylng statlon 42.
The slngle tacers 24a-c extend trom supplles thereot ~not shown) around assoclated gulde rolls 44a-c and 46a-c, and trom the gulde rolls to and through nlps between re~pectlve appllcator roll~ 38a-c and welght rolls 40a-c. The Ingle tacer tlutes 22a-c contact Ihe appllcator roll perlpheral surtace~ ss lhey pass through 13~9~9 lhe nlps, whereby the applloator rolls apply adheslve onto the flute~. From the appllcalor roll~, the slngle tscer~ extend to and come together in overlying relationshlp bctween a palr ot endles~ belts 48 and 50 of a comblner. The belt 48 extends around and is carrled by a palr of drum~ 52a and 52b, the belt so extends around and 1- carrled by a palr of drum~ 54a and 5~ib, and although not shown, mean~ are provided for rotatlng the drums at a ~elected speed to movo the belts. The belts deflne a conveyor mean~ for the single facers 2~ia-c, and pull the slngle facers through the apparatu~ and across the appllcator rolls. Also extendlng between the belts and beneath the lowermost slngle facer 24c 1~ a paper sheet medlum or faclng 56 obtalned from a supply thereof (not ~hown). In thls manner, the single facers snd faclng are brought Into overlylng relatlonshlp and carrled by the belts through a dryer ~tatlon 58 at the combiner to set the adheslve and form the composite cardboard sheet or triple ~scer 26.
'i'he amount and locatlon o~ adhesive applied onto the tlutes 22a-c depends upon the speed of trsvel of the ~Ingle ~acer- relatlve to the perlpheral speeds of their a-soclated appllcator rolls 38a-c. If the speed of the ~Ingle facer~ equal~ the perlpheral speed~ of the appllcator roll~, adhe-lve wlll be applled prlmerlly onto the flute tlp-. If the perlpheral speeds of the appllcator rolls 1~ slower or faster than ~Ingle facer speed, there wlll be ~ ~iplng actlon of the flutes across the appllcator roll~ and more or less adheslve wlll be applled onto the leadlnt or tralllng edges of the flute~.

13~!9~

Aocording to conventlonal ptactlce, In an attempt to control the speeds of the appllcator roll perlpherie~ ~_ relatlve to the speed ot travel of the slngle (~cers 24a^
o, the ~ssumptlon would be made that slnce the comblner belts ~ and 50 pull the slngle tacers through the mschlne, the speed ot the ~Ingle tacers 1- the rame 85 that ot the belts. The a~sumption would al~o be made that slnce the belts travel on Ihe drums 52a-b and 54~-b, Ihe rate Or rotatlon of the drums dlrectly correlates to the speed of travel ot the belts. Conventlonal practlce would therefore contemplate connectlng a sprocket on one ot the drums to an Input sprocket to a distributor by means of a chain, and then connectlng an oulput sprocket rrom the distrlbutor, by means or sdditlonal chalns, to sprockets carried on each applIcator roll 3Ba-c. The partlcular sprocket at the dlstrlbutor Input would detormlne the speed ol rotation ot the appllcator rolls relatlve to that ot the drum and, Ideally, the perlpheral speed~ ot the appllcator rolls relatlve to the speed ot travel ot the single tacers. However, In practlce the comblner belts sllp on the drum~, and the slngle tacer~ sllp wlth respect to the comblner belts, so varlatlons would occur In the Jpeed of travel ot the slngle tacer~ wlth respect to the speeds ot the appllcator roll perlpherles and, therelore, In the amount and locatlon of glue applied onto the flutes.
In addltlon, accordlng to conventlonal prectlce, the Jpeed- ot rotatlon ot the appllcator rolls would be Identlcal. Consequently, even If the speed ot travel ot the slngle tacer- relatlve to the perlpheral speeds Or the appllcator rolls could be malntalned conslant, 13C~969 because the appllcator rolls cannot be rolated at ditferent speed~ relatlve to each other, compensatlon In adheslve applicatlon cannot be made to account for dlfterent conflguratlon~ of flule~ or differences In the conslstencle~ of the Indlvldual slngle facers.
Therefore, to ensure that the ~Ing~e racers will be properly adhered one to the olher despile variatlons In adheslve appllcatlon and de~plte the Inablllty to control adheslve appllcatlon In accordance wlth flute contlguratlon and con-lstency, the prlor art al~o contemplates that an e%cess of adheslve be applled onto the flute~. Nowever, the ma~or component of the adheslve Is ~ater, whlch mu~t be evaporated In the dryer statlon 58 to ~et the adheslve, so applylng e~ces-adheslve to the flutes w-stes adheslve and Increases dryer energy requlrement-. More Importantly, and ot greater dlsadvantagc, the e~cess mol~ture applled to the flute~ vla the adheslve result~ In warplng of the resultlng cardboard ~heet 28 and causes ~rlbblng~ on the outer surfaces of the sheet. Consequently, Instead of being smooth, the surfaces of the cardboard 6heet wlll tend to conform to the underlyln~ flutes, so that It wlll be dlfflcult If not Imposslble to then apply hlgh quallty prlntlng or graphlcs on th- sheet.
In overcomlng the dlsadvantage~ of prlor adhesive applylng m-chlnes, In accordance wlth the present Inventlon, each appllcator roll Is Independently rotated at a rate controlled so that Its perlpheral speed i8 always malntalned In an Indlvldually preselected relatlonshlp to the actual speed of travel of the slngle facer c-rrled across Its perlphery. Thls Is accompllshed by havlng the frlctlon ~heel 28 of the 13~'~9~9 lachometer 30 rldo on the surface ol the triple facer cardboard sheet 26 t or as It le-ve- the comblner. The actual speed of travel of the slngle facer- Is therelore contlnuously sensed or monltored, and the tachometer generates and app~les to the mlcroprocessor 32 and motor speed controller 3~ a slgnal havlng a value In accordance wlth slngle facer speed. The motor speed controller, in addltion to controlling the speeds of operatlon of the motor~ 36a-c, recelve- Irom at least one of the motors, for e~smple the motor 36b, a signal havlng a value representatlve of the Jpeed of operatlon ot the molor, and therefore ot the perlpheral speed of the adheslve appllcator roll 38b, and couples that signal to the microproce--or. The mlcroproceJsor compare~ the ~ignal~ representatlve ot ~Ingle facer and motor Jpeed, and based upon the comparlson, and dependlng upon whe~her Ihe mlcroproces~or has been programmed so Ihal adheslve 1- applled prlmarlly to the ~lute tlp-, or more JO to the leadlng or tralllng edges of tho flute~, of Indivldual one~ ot the slngle ~acers, tho mlcroproce~or applle~ to the motor ~peed controller slgnals that cau-e the controller to Independently operate each motor 36a-c at an Indlvldually controlled peed, o that the perlpheral speed of each applIcalor roll 1~ Independently malntalned egual lo, greater thsn or les- than the speed of the slngle facer carrled acros~ It~ perlphery. For the sltuatlon descrlbed, the motors 36a and 36c are reterenced to the motor 36b, and are Independently operated at Indlvldually controlled speed- that h-ve a predetermlned relatlonshlp to the sensed ~peed Or tho motor 36b. However, the motor speed controller may ju~t as readlly recelve trom each motor a 13~ 9 signal representatlve of lls speed and couple those signalJ to the mlcroprocessor 90 that the mlcroprocessor then controls each motor so thet Its actuAI speed Is equal to a deslred speed. Since the dlameters of the appllcator rolls are ~nown and usuAlly Identicsl the arrangement enableJ the rate of rotation of eaoh roll to be independently accurately and variably controlled such that a predetermlned relatlonshlp or ratlo is malntalned between Its perlpheral speed and the actunl speed of travel of the slngle facer across Its perlphery.
The appsratus therelore enables preclse control to be malntalned over the amount and Jocatlon of adheslve applled onto slngle facer flutes by Independently controlllng the speed of rotatlon of each Indlvldual spplicator roll In accordance wlth the sensed actual speed of travel of thc single fa¢er carrled across its perlphery so that selected relatlonshlp~ are always malntalned between the speed o~ the slngle facers and the perlpheral speeds ot thelr assoclated appllcator rolls desplte varlatlons In the speed of the slngle facers. ~ach appllcator roll may be selectlvely rotated at rate- to apply adheslve to prlmarlly the flute tlps of Its assoclated slngle facer or to get a wlplng actloo ot the roil perlphery across the flutes to apply more or less adheslve to elther leadlng or lagglng edges of the flutes. Slnce the amount and locatlon of adheslve that must be applled onto the flutes for proper adheslon of the slngle tacers varies In accordance wlth flute slze and shape and ~Ith the conslstency of the materlal of the slngle facers and slnce the amount and locatlon will vary wlth changes in . .

~3~

the speed rela~lonshlps between the single tacers and their assoclated appllcator roll peripherles, the apparRtus adv~ntageously compensate- or and ellminates the nega~lve Intluence of such v-rlables. In consequence of the precise control over applleatlon o~
adhesive, and as will be turther described, as eompared wlth conventlonsl appllcators, adheslve consumptlon is reduced by about flfty percent, and the resulting cardboard product is nol warped and has very smooth outer surfaces onlo whlch may be imprlnted high quaJily graphl C8 .
The slngle faeers pass through nips detlned belween the adhesive appllcator rolls 38a-e and welght rolls 40a-c, whlch must be ad~usted to and malntalned at selected slzes, In aeeordanee with th thleknesses and type- ot the slngle faeers, for proper appllcatlon of adhesive onto the flutes without crushing the tlutes. The art contemplates manual ad~ustment of nlp slze, but the proeedure i- generally time Intenslve and inaeeurate, and must be repeated tor different types of slngle faeer-.
Aeeordingly, In further Improvlng upon the art, the Inventlon also contemplates automatie adjustment of the nlps betNeen the adheslve appllcators rolls 3Ba-e and welght roll5 ~iOa-c. Wlth reference to Flg. 2, Nhlch Illustrates an arrangement for ad~u6tlng the slze of the nlp between the appllcator roll 38b and weight roll 40b, It belng understood that a slmllar strueture Is provlded for each set of appllcator and welght roll5, each end of the welght roll ~iOb 1- ~ournaled for rotatlon In an arm 60. One end of the arm connects to a pi-ton rod 62 of a pneumatlc cylinder 64 that Is operable to either e~tend ~ 36 E3'~

the piston rod and move the weight roli away trom the applicator roll or retract the piston rod and preload the weight roll toward the appllcator roll. An opposite end of the welght roll arm reJts on an extenslon of a screw actuato- 66 ooupled through a gearbox 68 to a stepplng motor 70. The stepplng motor Is operated by a motor controller 72 to elther ralse or lower the screw actuator, and the motor controller Is controlled by the microprocessor 32. Carried on the arm for movement therewith Is a dlsplacement transducer 74 that applles to the mlcroprocessor a slgnal havlng a value representatlve of the dlstance between It and a target 66 mounted on the apparatus at a known posltlon wlth respect to the applIcator roll, and therefore o~ the size of Ihe nlp.
The Jignal facer 2~ib passes through the nlp between the welght roJI 40b and the appllcator roll 38b for havlne adheslve, plcked up by the appllcator roll perlphery from an adheslve pan 78, applled onto the flutes 22b as they are carrled across the perlphery. To ad3uht the nlp slze, the dlsplacement transducer 74 send~ to the mlcroprocessor 32 a slgnal representatlve of the slze of the nlp. The mlcroprocessor compares the slgnal representlng nlp slze wlth a preprogrammed deslred nlp Ize, and If the nlp Is smaller or larger than deslred, cause~ the motor controller 72 to operate the ~tepplng motor 70 to drlve the screw actuator 66 elther up or down to move the welght roll awsy trom or toward the appllcator roll, untll the nlp has the desired Ize. Durlng appllcatlon of adheslve onto the flutes, the plston rod 62 1- fully retracted, 80 nlp slze la determlned solely by the amount Or extenslon of 13~

the screw actuator 66, although for convenlence In threadlng Ihe single racer Ihrough the nlp, the plsIon rod 18 extendlble to move the welghl roll away from Ihe appllcalor roll and subsIanIially widen the nlp.
Adheslve plcked up by Ihe appllcalor rolls 38a-c lrom associated adheslve pans 78 Is metered prlor to being transferred to the slngle facer ~luIes.
Prevlously, meterlng was accompllshed by runnlng a doctor roll agaln-I the appllcaIor roll periphery, In a manner such Ihal a dlscrele fllm of adheslve was left on the perlphery, even when Ihe perlphery was engraved or cellular, i.e., prov!ded wlIh dlscrete adheslve carrying pociiels. decause of Ihe Inabllily of prlor apparaIus to accurately control appllcator roll perlpheral speed relaIlve to thal of Ihe slngle facer carrled across iI, it WA~ neces~ary Io leave a fllm of adheslve on Ihe roll perlphery ~o that an exces~ of adheslve would be transferred to Ihe tlutes Io ensure proper adheslon between Ihe slngle tacers. However, a maJor component ot the adheslve Is waler, so by Iransferring excess adheslve to the flutes, excess mols~ure was also transferred, whlch resulted In warplng of the resultlng oardboard sheel and a "ribblng" effect on iIs ouler surtaces, along wlIh waste of adheslve and Increased energy requlrements for drying and setIlng the adhesive.
The inventlon therefore also contemplates an improved doctor for metering adhe~lve on the appllcator roll perlpherles. As seen In ilg. 3, assoclated wlth each appllcator roll, such as the roll 38b, Is a doctor blade assembly comprlslni~ an alr cyllnder 80 having a plston rod 82 connected to one end Or an arm 8~i, an opposlte end of whlch ls ~ournaled at 86 for rolation.

13(~

An L-shaped bracket 88, mounted toward one of Its ends on the srm, carrles at Its opposlte end a doctor blade 90 secured between a palr of plates 92 and 94. An Inllstable tubo 96 acts on the doctor blade and urges Ihe blado tlp toward and agalnst the appllcator roll perIphery.
In operatlon ot the doctor, the cylinder 80 Is mounted so thst when Its plston rod 82 1- e~tended and the tube 96 18 Inflated, the tlp of the doctor blade 90 Is moved against the appllcator roll perlphery to wlpe the perlphery substantlally clean of adheslve, leaving behlnd only a llmlted amount of adheslve as carrled In cellular perlphersl pockets 98. Consequently, only the adheslve contalned In tho pocketa Is carrled and avsllable for tranJter to the slngle facer flutes, so the smount of adheslve trsnsferred to the tlutes Is llmlted. However, because of the preclse control over the perlphersl speed ot the appllcstor roll relatlve to thst Or the slnEle facer, the adheslve Is very precisely plsced at de~lred location~ on the rlutes~ 80 proper adheslon ol one slnglo facer to another Is obtalned even wlth a mlnlmum amount ot adheslve. In practlce, It has been tound that tho proclso oontrol provldod by the Inventlon ovor the appllcator roll/slnglo tacer speed relatlonshlps enables proper sdherence ot the slngle tacers one to the other wlth a reductlon In adheslve consumptlon to ~bout tltty percent ot what would otherwl~e be conventlonally requlred The reductlon In tho amount of adbeslve placed on the tlute-proportlonstely reduces molsture transfer to the flutes, whlch sub~tantlally ellmlnates tho warplng and ~rlbblng"

13~9~9 ... i problems that otherwise ocour in product made with conventisnal apparatus.
The invention Iheretore provides an Improved appsratu~ for and method of applylng adhesive onto the flutes of single acers that are adhered together and to a tAcing to form a cardboard sheet. After pa~ln8 through a supply ot adhesive the perlphery of ench appllcator roll 15 wlped substRntlally clean by a doctor leaving behlnd only 8 llmited emount of adhesive In the cellular perlpheral poc~et~ tor transfer to tlutes ot a slngle facer moved acros~ tho perlphery.
Normally the quantlty of glue transferred to the flutes wouJd not be sufrlclent to ensure proper adherence o-one slngJe ~acer to another and to the faclng. However because of the precl~e control available over the speed of rotatlon ot the appllcator roll and therefore over Its perlpheral speed relatlve to the speed or trave; of the slngle ~acer the llmlted amount of adheslve is so preciseJy positloned on the ~lutes that secure sdhesion o~ the slngJe facers and faclng sheet 18 ensured. As compared wllh conventlonaJ adheslve appJylng apparatus the one of the inventlon provldeD a reductlon in adhesivo consumptlon on tho order o~ about ~l~ty percent.
In additlon to the economles Involved in reducing adheslve consumption lhe reductlon In the amount ot adheslve appJied to the fJutes correspondlngJy reduces the amount o~ molsture added and thererore energy regulrements for a drylng proces~ to set the adhesive More importantJy slnce excesslve molsture Is a slgnlficant factor In causlng warplng of the resulting cardboard product and "rlbblng" on Its sur-aces the 13~ 3 !
reductlon In molsture trensferred to the tlutes sub~lantlally ellmlna~es the problems ot harplng and "rlbblng.~ The problem of nrlbblng," I.e., lhe tendency ot the taclng on the outer surtaces ot the cardboard sheet to contorm to Ihe underlying tJutes, so Ihst the surtaces are not smoolh and tlat, 18 partlcularly troublesome In ~he appllcation of hlBh quallty prfnting and graphlcs onto the cardboard. By ~ubstantlally ellmlnatlng "rlbblng," the apparatu~ ot the Inventlon theretore enables hlgh quallty prlntlng and graphlcs to be applled onto the cardboard.
Further, tor a glven thlckness of a resultlng cardboard sheet, when made Into a carton It~ stacking strength Is generally determlned by the slze of Its tlute~, such that the larger the tlute~ the greater Its stacklng strength. However, to Inctease the slze ot the ilutes, whlle maintainlng the cardboatd sheet at a given thlcknes~, requlre~ decrea~lng the thlcknes~ of the outer faclng, but that In turn aggravates the "ribbing"
problem and causes It to become more pronounced.
However, because of the llmlted amount of adhesive applled onto the tlutes, tlute ~Ize can be Increased, wllh a correspondlng decrease In thlckness ot the taclng, whlle stlll malntalnlng a very smooth outer surtace on the cardboard.
Whlle embodlments ot the Inventlon have been descrlbed In detall, varlous modltlcatlons and other embodlments thereot may be devlsed by one skllled In Ihe art wlthout departlng trom the splrlt and scope ot the Inventlon, as detlned In the appended clalms.

Claims (24)

What Is Claimed Is:

1. Apparatus for applying adhesive to flutes of a plurality of corrugated webs, comprising a plurality of adhesive applicator rolls; means for transferring adhesive to peripheries of said applicator rolls; means for moving the webs in unison and at the same speed of travel, such that each web moves across the periphery of an associated one of said applicator rolls with its flutes against said periphery for transfer of adhesive from said periphery to the flutes; mean for sensing the actual speed of travel of the webs; and means responsive to the sensed actual speed of travel of the webs for rotating each individual applicator roll at a rate of rotation that is independent of the rate of rotation of the other rolls and that is varied as necessary to maintain constant an individually selected and adjustable relationship between the peripheral speed of the roll and the sensed actual speed of travel of the webs, despite any variations in the sensed actual speed of travel of the webs, to thereby control the amount and location of adhesive applied on the flutes of each individual one of the webs.

2. Apparatus as in claim 1, wherein said means for rotating relates each said applicator roll independently so that, depending upon the selected relationship between its peripheral speed and the speed of travel of the webs, its peripheral speed is the same as, a predetermined amount less than or a predetermined amount greater than the speed of travel of the webs.

3. Apparatus as in claim 1, including means for doctoring adhesive transferred to each applicator roll periphery prior to transferring adhesive from the periphery to flutes of its associated web.

4. Apparatus as in claim 1, including means for bringing together the adhesive carrying webs into overlying and adhering relationship to form a composite sheet of material, and wherein said sensing means senses the actual speed of travel of the composite sheet.

5. Apparatus as in claim 1, wherein said means for rotating includes a plurality of motor means, each for rotation as associated individual one of said applicator rolls, and means, coupled to said sensing means, for operating each said motor means to rotate each said applicator roll at a rate that is varied as necessary to maintain constant the individually selected and adjustable relationship between the peripheral speed of the applicator roll and the sensed actual speed of the applicator roll and the sensed actual speed of travel of the webs.

46. Apparatus as in claim 5, wherein each said motor means comprises electric motor means, and said means for operating each said motor means includes a motor speed controller for operating each said electric motor means and for sensing the speed of operation of at least one of said electric motor means, and a microprocessor coupled with said motor speed controller and said sensing means for comparing the sensed actual speed of travel of the webs and the speed of operation of said at least one electric motor means and for causing said motor speed controller to operate each said electric motor means such that the individually selected and adjustable relation ships are maintained between said applicator roll peripheral speeds and the sensed speed of travel of the webs despite any variations in the sensed speed of travel of the webs.

7. Apparatus as in claim 4, wherein each said applicator roll has cells in its peripheral surface, said means for transferring adhesive to said applicator roll peripheries fills said cells with adhesive, and said doctor means removes substantially all of the adhesive off of said applicator roll peripheries except for adhesive in said cells, so that only the limited amount of adhesive in said cells is transferred tot he flutes of the webs, whereby adhesive consumption is reduced and warping of the composite sheet and ribbing on its surfaces are substantially eliminated.

8. Apparatus for applying adhesive in flutes of a plurality of corrugated webs, comprising a plurality of adhesive applicator rolls; means for transferring adhesive to peripheries of said applicator rolls; means for moving the webs in unison and at the same speed of travel so that each web moves across the periphery of an associated one of said applicator rolls with its flutes against said periphery of transfer of adhesive from said periphery to the flutes; means for sensing the actual speed of travel of the webs; means responsive to the sensed actual speed of travel of the webs for independently rotating each applicator roll at a rate varied as necessary to maintain constant an individually selected relationship between the peripheral speed of the roll and the speed of travel of its associated web, despite any variations in the speed of travel of the webs, to thereby control the amount and location of adhesive applied onto the flutes of individual ones of the webs; a plurality of rotatable weight rolls, each associated with an individual one of said applicator rolls and defining with said applicator rolls nips through which their associated webs pass; and means for adjusting the sizes of said nips, said adjusting means including means for detecting the sizes of said nips, means for comparing detected nip sizes with preselected desired sizes and means, responsive to said comparison, for moving said weight and applicator rolls relative to each other to bring said nips to said desired sizes.

9. Apparatus for adhesively adhering a plurality of corrugated cardboard webs and a feeling in overlying relationship to form a composite sheet of cardboard, comprising a plurality of rotatable adhesive applicator rolls, each having a periphery across which an individual associated one of the webs is extendible for transfer of adhesive from said periphery to flutes of the web; means for transferring adhesive to said applicator roll peripheries; conveyor means downstream of said applicator rolls for receiving the webs and facing, moving the same into overlying adhering relationship, and pulling the webs in unison and at the same speed of travel across said applicator roll peripheries for a transfer of adhesive from said peripheries to the web flutes; means for rotating each said applicator roll; means for sensing the actual speed of travel of the webs; and means, responsive to the sensed actual speed of travel of the webs, for controlling said rotating means to rotate each said applicator roll at a rate of rotation that is independent of the rate of rotation of the other applicator rolls and that is varied as necessary to maintain constant an individually selected and adjustable relationship between the peripheral speed of the roll and the sensed actual speed of travel of the webs, despite any variations in the sensed actual speed of travel of the webs, to thereby control the amount and location of adhesive applied onto the flutes of each individual one of the webs.

10. Apparatus as in claim 9, wherein said controlling means controls said rotating means to rotate each said applicator roll at a rate such that, depending upon the selected and adjustable relationship between its peripheral speed and the sensed actual speed of travel of the webs, its peripheral speed is the same as, a predetermined amount less than, or a predetermined amount greater than the speed of travel of the webs.

11. Apparatus as in claim 9, including doctor means for doctoring adhesive transferred to each applicator roll periphery prior to transferring adhesive from said peripheries to flutes of the webs.

12. Apparatus as in claim 11, wherein each said applicator roll has cells in its peripheral surface, said means for transferring adhesive to said applicator roll peripheries fills said cells with adhesive, and said doctor means doctors substantially all of the adhesive off of said applicator roll peripheries except for adhesive in said cells, so that only the limited amount of adhesive in said cells is transferred to the flutes of the webs, whereby adhesive consumption is reduced and there is a reduction is moisture transferred to the flutes that substantially eliminates warping and ribbing on the surfaces of the composite cardboard sheet.

13. Apparatus as in claim 9, wherein said sensing means senses the actual speed of the webs at said conveyor means.

14. Apparatus as in claim 13. wherein said conveyor means comprises a pair of conveyor belts in overlapping relationship and the webs, after leaving said applicator rolls, move into overlying and adhering relationship with the facing between said belts and said belts pull the webs across their associated applicator roll peripheries, and said sensing means senses the actual speed of travel of the composite cardboard sheet exiting from between said belts, independent of the speed of travel of said belts.

15. Apparatus as in claim 9, wherein said means for rotating comprises a plurality of electric motor means, each for rotating a respective one of said applicator rolls, and said controlling means operates each said motor means to rotate each said applicator roll at a rate that is varied as necessary to maintain constant the individually selected and adjustable relationship between the peripheral speed of the applicator roll and the sensed actual speed of travel of the webs.

16. Apparatus as in claim 15, wherein said sensing means comprises a friction roll for riding on at least one of the webs and a tachometer coupled to said friction roll for generating a signal having a value representative of the speed of travel of the webs, and said means for controlling responsive to the value of said signal for operating each said electric motor means.

17. Apparatus as in claim 15, wherein said means for sensing generates a first signal having a value representative of the actual speed of travel of the webs, and said means for controlling comprises a programmable microprocessor and a motor speed controller for receiving said first signal, said motor speed controller is coupled with said microprocessor and with each of said electric motor means for controlling operation of each said motor means and for receiving from at least one of said motor means a second signal having a value representative of the speed of operation thereof, said motor speed controller coupling said second signal to said microprocessor and said microprocessor comparing said first and second signals and causing said motor speed controller to operate each said electric motor means such that the selected and adjustable relationships are maintained between each said applicator roll peripheral speed and the sensed actual speed of travel of the webs, despite any variations in the speed of travel of the webs.

18. Apparatus for adhesively adhering a plurality of corrugated cardboard webs and a facing in overlying relationship to form a composite sheet of cardboard, comprising a plurality of rotatable adhesive applicator rolls, each having a periphery across which an individual one of the webs is extendible for transfer of adhesive from said periphery to flutes of the web; means for transferring adhesive to said applicator roll peripheries; conveyor means downstream of said applicator rolls for receiving the webs and facing, moving the same into overlying adhering relationship, and pulling the webs across said applicator roll peripheries for a transfer of adhesive from said peripheries to the web flutes; means for independently rotating each said applicator roll; means for sensing the actual speed of travel of the webs; means, responsive to the sensed actual speed of travel of the webs, for controlling said rotating means to independently rotate each said applicator roll at a rate varied as necessary to maintain constant an individually selected relationship between the peripheral speed of the roll and the speed of travel of its associated web, despite any variations in the speed of travel of the webs, to thereby control the amount and location of adhesive applied onto the flutes of individual ones of the webs; a plurality of rotatable weight rolls, each associated with an individual one of said applicator rolls and defining with said applicator rolls nips through which their associated webs pass in extending across said applicator roll peripheries; and means for adjusting the sizes of said nips, said adjusting means including means for detecting the sizes of said nips, means for comparing detected nip sizes with preselected desired sizes and means, responsive to said comparison, for moving said weight and applicator rolls relative to each other to bring said nips to said desired sizes.

19. A method of applying adhesive to flutes of a plurality of corrugated webs, comprising the steps of transferring adhesive to peripheries of a plurality of applicator rolls; moving the webs in unison and at the same speed of travel, such that each web moves across the periphery of an associated one of the applicator rolls with its flutes against the periphery to transfer adhesive from the periphery to the flutes; sensing the actual speed of travel of the webs; and rotating each applicator roll, in accordance with the sensed actual speed of travel of the webs, at a rate of rotation that is independent of the rate of rotation of the other applicator rolls and that is varied as necessary to maintain constant an individually selected and adjustable relationship between the peripheral speed of the roll and the sensed actual speed of travel of the webs, despite any variations in the sensed actual speed of travel of the webs, to thereby control the amount and location of adhesive applied onto the flutes of each individual one of the webs.

20. A method as in claim 19, wherein said rotating step comprises individually rotating each applicator roll so that, depending upon the selected relationship between its peripheral speed and the speed of travel of the webs, its peripheral speed is the same as, a predetermined amount less than, or a predetermined amount greater than the speed of travel of the webs.

21. A method as in claim 19, including the step of doctoring adhesive transferred to each applicator roll periphery prior to transferring adhesive from the periphery to flutes of its associated web.

22. A method as in claim 21, including the step of bringing together the adhesive carrying webs into overlying and adhering relationship to form a composite sheet of material.

23. A method as in claim 22, wherein each applicator roll has cells in its peripheral surface, said step of transferring adhesive to the applicator rolls peripheries fills the cells with adhesive, and said doctoring step removes substantially all of the adhesive off the applicator roll peripheries except for adhesive in the cells is transferred to the flutes of the webs, whereby adhesive consumption is reduced and warping of the composite sheet and ribbing on its surfaces are substantially eliminated.

24. A method of applying adhesive to flutes of a plurality of corrugated webs, comprising the steps of transferring adhesive to peripheries of a plurality of applicator rolls; moving the webs in unison and at the same speed of travel such that each web moves across the periphery of an associated one of the applicator rolls with its flutes against the periphery in transfer adhesive from the periphery to the flutes; sensing the actual speed of travel of the webs; and independently rotating each applicator roll, in accordance with the sensed actual speed of travel of the webs, at a rate varied as necessary to maintain constant an individually selected relationship between the peripheral speed of each roll and the speed of travel of its associated web, despite any variations in the speed of travel of the webs, to thereby control the amount and location of adhesive applied onto the flutes of individual ones of the webs, wherein a plurality of rotatable weight rolls area associated with individual ones of he applicator rolls and define with the applicator rolls nips through which their associated webs pass, and including the further steps of detecting the sizes of the nips;
comparing the detected nip sizes with preselected desired sizes; and, based upon said comparison step, moving the weight and applicator rolls relative to each other to bring the nips to the desired sizes.