Note: Descriptions are shown in the official language in which they were submitted.
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Field o the Inventioll
;' Tllis illvention relates to thc book binding art, and
more particularly to the application of a wide band of aclhesive
l,to a spine area of the book, in connection with securing the cover
to the body.
,
~ ; Back~round of the Invention
.~ _
-This invention is useful in the mallufacture of both hard
bound and paperback books, and description of the general manner
by which covers are applied to each type of book is given as
~background.
,' The body of a hard bound book usually comprises an-
' assembly of individual printed sheets or leaves, which may be
sewn or otherwise held togetller along cen~erEolds in groups
'of 16 or more, to form sections called "signatures." The
'signatures may be assel~led by additional se~ing, bindin~ tapes,
~ cords, or the like, along a spine which is usually rounded, to
llform the body of the book. On the front and back of the body,
! stronger and heavier "end papers" may be adhered to the flrst
~and last signatures or leaves of the bool; ~o facilitate attach-
~ment oE the body to -thc covel- or "ca~e." The C.lSC ~.i.i..l. COlll-
jprise front and back covers, cloth bound, ~hich are connected
. I ~
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by an intecJra:l spine portiol, hetween thc~ l`he covers are hingecl
alontj each ed~fe co E the S~illC` ~ i\ yrOOV(-' i!, ~l.sually f^frovi dcd in
tlle case at each hinc,~e line to a]low the cover to l~e opened and
closcd eas ily .
In a-ttacllincJ -the case to tht_ body -to form a hard bound
book, according to one common technique, the center of a piece o:~
fabric eailecl "crash" is glued to -the bocly spine along the center-
'olds oE the siqna-tures, in an operaLion called "lining up. "
Narrow flaps of the crash ex-tend along the outside o E the end
papers on each side o,E the body . - In tl~e ne~t s tep, called "casinc~,
in", the body is glued to -the case so tha-t }-~inc~e folds Or the end
papers -are ad jacen-t the spine of the, case. For -this purt~ose
adhesive is applied to both sides of -the cras,h Elaps and to thc~
faees of the end papers adjacen-t the insides of the covers of
the case . The end ~ papers are pasted to ,tlle inside o f -the covers,
-to enclose and conceal the crash. The case and body so assembled
may l)e plaeed in a press to form the groove a t either side o f the
c~ase's spine, in a process 1 nown as "buildincf in. " The bocly is
thus bound to the case at the hinge so that the eovers and leaves
20 1; are movable wi-th respeet to eaeh other. The cover spine is said
to be "open" or "loose-bac]ced" ~f i-t is not secured directly to
the body spine. In " tight-baek" books, the cover spine is adhered
directly to -the body spine . In ei ther east-~, however, ,ldhesive is
applied in a SpilltC area, ant:l usually on the body spine.
In thc rnanuEclcturt_ oE pa~erbaeks clll(l othcr sofi bound
bool~c;, ~ tlC~ y c)~ In~ C)t ~ t~(lt ~ r ill c,;,~ c~L;,
alld the CC)VC~I^ compri~-;es a i~le~ible ~ l~ce~ which i.s ~JIue(:l direcl~ly to
i, I;ht,a l)odS/ ';~ C.- ,~ l, covcr ])oOkS n~-~? Oi-l.t`ll i~OUIlCl l)y 1:11(' SO-C~ c`(l
~ "perEect bindirlc,~" process, which relies solely Oll adhesive and the
30 , E ii~o u~ u ~ o l: 1 llc l~al~t~r ~o l~t) l cl ~ oolc ~:o(l~ l llc~l . Lll l:his
:
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, ~rocess the p~ es are pre-rouclhened to opc:n up fibers aL l:he
1, spine of l:he ~>ody, to make more arett ~lvai lc.~ c for the ~J] ll~ arld to
,Icause .interl.ockirlg of tl~e fil:)ers irom one pac~e to another. A
Il first higllly flexible ylue or primer is applied to tlte rouc3hened
j area to form a band that holds the inclividual pages together
,,
,at the spine. On some machines a strip of stretchable cloth or
, paper is appli.ed for further relnforcemen t . rrherea f ter a second
type of adhesive, called a "covering ~Jlue", is app:Lied (scconds
laterj ~ to hold the cover to the pages. This cJlue is usually a
0 I much lleavier type thall the primer.
Regardless of the speciEic -techniclue used :Eor hard
bound or soEt bound books, it will thus he appare~nt tha-t the
; ~ ,
splne of tlle body is adhered to the cover ei ther dlrec tly, or
ndirectly -through an intermedlate kraft paper and/or crash, and
that the cover is hinged wi th respect to th. spine . The durability
of any~book thus depends on the securi-ty of the adhesive attachment
,
- ! of -the body to the cover .
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The Prior Art
i Prior art book bindinc3 technlques llctve used animal glue
,
'' for many years . As shown in Parikh and Cronin, "pllttlity Control
of Animal-Prot2in Adhesives in the Boo]cbinding Industry, "
jjAdh slves cLe, ~larch 1977, pages l9 21, the adhesive may be ap-
plied from all opc>n pol hy sequentia:l. appl.icat:ion rollers to the
ocly sp.ine . Tlle inver ted book body, in a l~ook holdincJ clt-tmp, is
1~ conveyecl over tl~e rc:~ Lc~rs wl~:i.ch cle].i.vc.~:r l:l)e (~ e upwt-trc~ to thc~
11
Spille. 1~ reVerse].y-rOtcll:in(J SL~illner :i.S tl~;Ually provided in an
attempt to wil)e excess qlue :~rom -tlle sr)inc! an(l t.he:reby pl-ovide a
, more uniform fi.lm of ~JlUe .
.
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llot mel~ acllle<ii.ve llas also heell used as -thc? ac!hesive,
as shown in lle~ller, Jr. U.S. Patent 3,730,806, and has been
applied by rollers similar -to the manner i.n which anilllal glue
is applied. IJo-t melt adhesive has also }~een applied by extruding
it as multlple parallel beads or lines from one or rnore e,ctrusion
, nozzles spaced close:l y ad jacen t the cover or body .
,~ The Problem in the 7~rt
1', .
¦~ Whether hot melt or animal glue is used, it has proven
llvery dif:Eicult in practiee consistently to apply a uniformly thick
l~ adhesive film. ~t leas-t in part this results :Erom poor eontrol of
' I
viseosity. Viscosi-ty is closely related -to temperature for hot
meJ t adhesive, and poor temperature control causes undesirable
.viscosity changes. With respee-t to animaL cJlue, ~hell it is heated
to the range of roughly 130-150 F (appli.cator -temperature), water
losses oceur in the adhesive in the open pot. This causes an in-
crease in percent solids and thereby chancJes viscosity. Whatever
its~ cause, poor control of -the adhesive viscosity ultimately i.mpairs
the quali ty of the book
l~here hot melt glues have hc-~en appl.ied as parallel ex-
I!truded beads in bookbinding operations, difficulty has usualIy been
experienced in "squeezing out" the extruded beads to form a unifo:rm
film. Becau.,e of equipmen-t spacinq, the beads cooJ. somewhat before
the eover or eLas!~ ; contaeted w:ith the bea(.ls on l~he body spine.
S ueh coo l. in~J i llC L c!~ls ~s vi. s eos i ty to thL~ e x l:~?l~ a l. :i. t i s o f t:e
,clif~icult to s((ueeze out l~ e beac~s sn:Ef:iciellt:ly to (~el a uni..Eor
~:Eilm. ':L'he tllic~ "~ads may "I:el.egr.ll~h" tlll:(Ju(lll l.hc COVeL- -;pine
to presellt an unsi~Jhtly appearance; :in acldition, the rela-ti.vely
thic]c, narrow }~c.?ads provide poor~ adherellce.
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I By l~ invellt:i.on ~.he d:iE:Eicult:ic~: of l~ol:h Lhc .roll-on
; and the extru(:le~cl he~cl tecllr~ u~s ~or ~pl?l~:Lr~ I.ue~s in book-
bincliny operatiolls are c~vo:icled and fl.:Lms of more con~isten-tly
l~uniLorm coveraqe ~Ire a~plit-~d.
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~I Summary of the Invention
In accordance with the inven tion, -the hody, cover,
crash and/or o ther binding elemen t ol the :book is moved rela tively
., ~ i
past a hot-Mel-t cJlue applying station h~ving a "flat fan" orifice
,wllich is aligned wi-th the adhesive-receivinq area Oll the: surace
: 10 1Ito be coated, with the direction of movement being parallel to
~: ~I the spine. The flat fan orifice i.s ~aligned so -that its long a~tis
extends transversely to the direction of moveniell-t. B~ rdraulic
-, ~ : : I
j pressure the hot me].t adhesive is pro jec-ted throuc3h -the orifice
:
in the form of a flat sheet onto the adhesive-receiving area. By
reason of -the relative movement an adhesive band is thereby
deposited, running parallel to the direction of movement. This
band is of uni:form thickness and coverage. l~oreover, the glue as
,applied by this technique achieves better pene-tra-tion between ad-
I jacent leaves or signatures to improve the edye bondincJ thereof.
I Additional ori.ices may be provi.ded to apply narrow glue bands
adjacent the joint or hinge area, parallel -to the plalle of the
Il leaves .
.1 .In carryinc3 out tlle method, t~he :Lic;lll.id hot Ine:Lt adhesive
is pro jected throucJIl a "flat fan" or ribboll nozz.le, .Erorn wllich
, it cmor-~es as a :la~era:l.:l.y divercJi.n~J, thi.ll, .E:I.at sheet. rrhe
sllc~et may l~ecolllc a spl-ay by brt-~alcil~l into cliscrete drople-ts in
1icJht to th(~ t:clrcJet, clel~cllclillcJ orl thc cl:i.stclllce bel:wcell tht-! noz.%lc
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arld tlle a~lh(sive receiv:in(l ar~;l. At close ol-iE:icc-c;pille Sp.lCillCJ
the sllctt i ~ ir~(J EJ^ol-n tlle r-lo~le mly r(-~ in v:irtllllly co~ ;rluour;
(unatomized) as a practica:L mltter. ln either case such pro-
I!jection diE~ers Fro~n ex-trusion ~Jhel~c-~in thc rnlterial is shapecl
¦ by passing throuc~h the oriFice ancl re-tains e~ssen-tially that same
sectional shaL~t and dirnension -thereafter in moving -to the tarcJet.
In the present lechll:iclue -the adhesive leaves th(~ no~zle ls a flat
fan which e~pands laterally in w:idth anc~ which may also chancJe
I in thickness (rneasured throucJh -the sheet) wllile in flic~ht toward
10 ~ I the taryet. This technique provides a be-tteJ- film both in terms
~'of viscosity and uniformity of thic]cness in comparison to pre-
vious glue wheel and ex-truded bead cllue applicatioll -techniques. A
further advantaqt is that it enables adhesive to be applied w:ith
,1 .
the spine "up whereas priox c31ue whee] applicatioll has required
Ithat the spine or backbone be in the down position which in -turn
; required reorienting the body if the casirl~l-in maehinery rtquired
the spines to be facing up.
~specially good results are obtaillecl usillcJ the methoci
of -this inventioll when the hot melt adhesive is applied in foalned
l condition, i.e~. contaillincJ a mass o~ il)ternal bubbles or ~as
~inclusions. This has been found to provide better bond:incJ
beeau~e oE better pene-tration oE aclh(c;:ive into the stock; to
provic~t a mucll lonc-~er 'open t:ime ; bel-l:tr ilow chaLIett~ ;tics
' than simiLaJ- bllt unEc)amecl adhtsivt:!, 1 a rescult oE w}-l:ich it can seep
into the crevice( betwten atl-jaeen~ pac]e; at l-lle edcJe; arlcl to ~errnit
s~ l. lc~ t i l~ . r ~ c~. i vl~ L~ ,r~l .
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In one partlcular aspect the present invention provides
in the binding of a book cover to a body of leaves to form a
bound book, wherein the cover and body each have a spine and
the cover is attached to the body by means including a band of
adhesive on the spine of at least one of the body and thecover,
an improved method of applying the band of adhesive
comprising,
dissolving a gas under pressure in the molten hot melt
'adhesive,
moving the one of the body and the cover relatively past
: a flat fan orifice which is aligned with and spaced from the
spine thereof, the direction of movement being parallel to the
spine, the orifice extending transversely to the direction of
movement,
; at least one of the spine and the orifice being curved
: transversely, the distance between the orifice and the spine
varying across the width of the spine,
projecting a flat fan of hot melt adhesive throu~h the
orifice onto the spine,
the gas in the adhesive expanding in situ on the spine
to form a foam band, thereby providing an adhesive band of
uniform thickness thereon which runs parallel to the direction
of movement, the band having a width greater than that of the
orifi.ce as a result of the lateral expansion of the fan in
~light to the spine,
the distance between the orifice and the spine being
several times the thickness of the foam band,
and bringing the cover and body together so that the
adhesive band secures them together.
In another particular aspect the present invention provides
in apparatus for binding a book cover to a body of leaves to
form a bound book, wherein adhesive is applied to the spine
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of one of the body and the cover in an adhesive applying
station while moving therethrough on a conveyor,
the improvement wherein the apparatus includes adhesive
applying means comprising,
- a source of hot melt adhesive,
supply means for dissolving a gas in the molten hot melt
adhesive under pressure and for ~delivering the solution so
formed from the source to a nozzle,
the nozzle being a ribbon noz~le which is spaced from
the spine where the latter moves through the station, ::
the nozzle oriented transversely to the conveyor and
haviny a flat fan spray orifice for projecting the molten
- adhesive with the gas contained therein as a spray in the form
of a flat fan across the space between the orifice and the spine,
at least one of the spine and the orifice being curved
transversely, the distance between the orifice and the spine
. varying across the width of the spine by reason of the curvature,
f the supply means inc~uding a pump for developing a pressure
on the adhesive which is sufficient to project the adhesive
from the orifice as a fan which expands laterally in flight as
it moves across the space between the orifice and the spine,
thereby to deposit the adhesive as a band extending along the spine,
the gas in the adhesive in the band extending in situ
on the spine to form a foam band,
the foam band as formed on .the spine having a width
greater than that of the orifice as a result of the lateral
expansion of the fan as it moves across the space,
the distance between the orifice and the spine being
several times the thickness of the foam band, so that the
orifice does not physicall~ contact the spine.
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Des_ript.ion o E the DrawincJs I -
The invention can best hc :Eurtller descrlbed~ by
referrincJ to the accompanyillcJ drawin~Js, in wllich
1-
j, FicJure 1 is an end view of a so.Et bound boo]c in which
the cover and bocly have been adhered by thtC` "perfect" blndincJ
process; t
Figure 2 is a diagrar~ atic pe.rspectivt~ view of apparatus
utili~zing the invention to apply hot mel-t adhesive to; the spine
of a book hody in the perfect bindlng p.rocess;
10: ~ Figure 3 is a perspective view illustrating apparatus
l.in accordance wi-th another embodiment o-l~ the inven-tion for
t applying a band of adhesive onto a rounded book body spine, and
simultaneously~ applying adhesive jOlll~t lines at the cover hinge
areas; and ~ :
Fiyure 4 is an enlaryed axlal section showing one form
of no:zzle which is useful for projectlng adliesive as a flat sheet,
in carrying out the invention.
:, ~
De tailed Description
slthougll the invention is use.Eul .Eor applyiny hot
~20 ~ melt adhesive in various types of bookhindin3 processgs, .~or ~;
~ I purposes o~ illustration i-t is describe~d nereinaf teJ~ primarily
.in relal:i.on to tlle so-called "perfect b:incl:in~J" teclln.i~ue, ~ecause
ilat tecllrliclue .i.s so wi.de:l.y used . Ilowever, L t should be unders tood
that: the i.nverltion .i.s not limitecl to thilt l ecllniql;le alone ancl
other crash i.~pl~ly.i.nc~ t:ecll~ ues, clS lndlcatc d hereill.
I I
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~l ]n Figure 1 is illustrated a so.Et cover book having a
tigh-t baek and bound by the "per:Eeet bindi11cJ" -teehnique. The
body lO of -the book, i.e., the so-ealled "book bloek", eomprises
1l a group of shee ts or leaves ll whieh are ac1hc~red t:ogether at
,I their spine 12 by a band of adhesive 13. The flexible eover l4
l, has front and baek sides 15 and 16, respeeti vely j conneeted by
,l an inte(Jral eover spine 17 whieh is adhered to spine 12 o:~ the
body by the adhesive band 13. : '
' :
In this -type of bincling, tl1e adl1esive band 13 lneludes
: lO ll two glue layers: a :~lexible primer and a l1eavier eovering or main
! I
glue, as previously indieated. The primer is applied firsl~, to
the pre-roughened edges of the leaves ll to penetrate -the sheets
~ -
I and~ prepare them :Eor the second or eoveri:ng adhesive. Both primer
and ho-t mel t covering cllues are well-lcnown and eommereially avail-
able, and do not eompr:ise the inven tion .
c : Because of its low viseosity the primer glue can be
i
. ~ , applied by convei1tional glue wheel technicluc?s. Pre.Eerably, how-
ever, it is appl.iecl, as i.s l:he main g].ue j clS a :Elat sheei: pro-
eeted in aeeordanee with this invention. In the deserip~-tion oE
~I the preEerred embodiment whieh follows, both the primer and the
', eovering adhesives are applied by the same teehnlque of the
inven tion
As showl1 Ln Figure 2, i.n t~he 1?er:~t.~et bindinq p,roeess
a .series o~ bool~ bod.ief;, eaeh desic~nated by lO anc'l gr:ippec1 between
,i
i; two oE)poi~ecl ClClmpS 27 allCl 28, ~re earrietl alo11c~ a C-isha1)ed path
25 by cl Co11VC~yo~ Wlli.C'Il Illcly 1~(? COIIVC?II l::i.OIl~ lc Cl.;lllll)i'.; COI- tcl.il1i.
~,1 the book l~oclies are earrie-1 t~ ot~1()h a l~r~ nc-r static~11 c:le-sicl11atec1
I
I cJenerally by 29 .~1: whi.cl~ tllt' pr~ cr llUc i'; .-tpl):l.i.ec1, ~ el~ t11rollt~Jl
i
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a main or covering adhesive-applying s-ta-tion 30 wherein hot
melt covering glue is applied in accordance with the invention.
Meanwhile/ the book covers 1~, in horizon-tal orientation, are
carried on separate conveyor past a joint glue station 34,
whereat spaced adhesive lines 22 and 23 are applied to each
cover to provide cover joints as shown in Fig. 1. From joint
glue station 34 the covers are carried to the binding station
31 where the covers and bodies.are brought together and the
covers are clamped to the body until the glue has set up, to
form the assembled book.
At both the primer station 29 and the coveri.ng ad-
hesive s-tation 30, -the adhesives are supplied from sources each
of which include a melting chamber and pump, through a heated
hose to a heated gun and through a nozzle having a flat fan
orifice. With reference to the covering adhesive station, a
heated hose is designated at 36, a gun at 37, a nozzle at 38,
and a nozzle or.ifice at 39. The nozzle is shown in more detail
in Figure ~.
Reference is made -to my co-pending appl.ication Serial
No. 308,063, filed July 25, 1978, wherein -there is described a
supply, gun, and nozzle which can be used to project a fla-t
sheet of hot melt adhesive, suitable for use in this invention.
Briefly, however, the hot mel-t adhesive supply may be of known
type, fvr example as shown in Scholl U.S. Patent 3,96~,6~5,
assîyned to the assignee of this applica-tion. Such supply ap-
paratus includes a hopper for rece.;.ving hot melt glue pellets,
a gr:id melter, a reservo:i.r AIICl A pump Eor Ec)rcibly moving the
mo].ten material through the hose 36 to the gun 37. Commercially
available hot
jr~ - 10 -
, mclt rldl~O':.i V(~ Ol`ltlll La ~ f ~ cxl-rl.lc;io~ ;lS tl~e covor:in~l ;
', adh~s:ivc~ )o]c ~ C~ CI~c ~rj~li.t~ )r~ i.c, tllc
ot me.l.t adllesi.ve soJd by ¢astnlall l~ocklk ~om~ y, I~.i.nyciL)o~
.i`enllessee, uncler their desicJnation "~ST~OND A-3~' 1
Yrom the supply -th~ adhesive is,delivered throll(3h a
., heated hose to a gun which, for example, may be of the Iype shown
ln Balcer et al Reissue Pa-tent 27,865, rei.ssued January 1, 137~1, .
~, to which re~erence may be hacl. ,
~' The adhesive is applied to the boo]; body while it is
'; i
L0 movinc3 E~as-t the (~UIl nozzle 38. Si.nce the conveyor may carry the
,` body at a line speed which may be as hi~Jh as 400 Eeet per minute
, or more, a timer may be used to triyger automatic operat:ion of
i
the gun. Sui~able structure for the timer is shown in Alyeri e~
al U.S. Patent 3,682,131, to which referellce may be had.
l' Gellerally the same type of equipmell-t may be usecl at the
j, primer stati.on 29 -to apply the pri.mer, althouclh it is less
viscous and can be applied at lower pressures.
The molten coverincl adhesive is apl~lied to the c3un 37
under pressure, ior example at a pressure in the rancJe oE about
1 100 to 1500 psi. The nozzle should be spilced from the spine oE
l:he body, r~ltller ~han :in contact witll it. A ~su:itab:Le sL~a(,iny
', is about 2", bu~ l:lli.s can va:ry accordin~J ~.o l:he wic'l~h o~ the
spin(-~, adhes.ive tempc!ral~lrc atld al~p'l.ic.lti.c)rl L~resslll^e, oril.i.ce
, conE~ ratioll, ancl so on.
i i. ( l l l 1-0 /1 '; I l()l~/.Ci ;1 1 10 7, % I.C~ 3 ~ J~ i l ! i il J~ :)C)I1 rl O '~
Witll C)lle su.i.L,Il~ie conE:i.(Jural::ic)ll r.'OI- ori.E:ice 3'). 'l'l~:i.c; p.lrticul.ar
oriEice Sllrlpe/ ho~ever, is not crit,ical. Other noz%les o~ the
Elat Ean tyE~c are krlown per se and are avai.lab~e commercicllly.
,
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Such nozzles are sold under the designations "~la-t spray noz-
zles", "flood je-t noxzles", and "flat spray pat-tern" nozzles,
by several manufacturers and do not themselves comprise the
invention.
The width of the nozzle orifice 39 (the dimension
of the orifice transverse to -the direction o~ movernent MD),
may be one-hal-f inch or less, but the flat sheet projected
from i~ spreads or diverges at an angle which may be as much .
as 90 or more and there~ore may lay down a ~and having a
substantially greater width than the nozzle, up to 4" or rnore.
By reason of the relati.vely high viscosity of the hot melt
covering glue and the proxi.mity of orifice 39 to the book
spine, the flat sheet of adhesive projec-ted through the ori- c
~ice 39 and impinging on the book may differ ~rom a true spray
: in that it may be almost continuous and unatomized.
The invention can usefully be carried out with hot
melt adhesives wherein the adhesive is applied as an unfoamed
or continuous liquid phase to -the substra-te, ~ut as already
indicated it is more advan-tageous still to apply the adhesive
in a foamed state. Foam hot melt adhesives, recently dis-
covered, are disclosed in U.S. Patent No. 4,059,466, to Scholl,
Janner, Stumphauser and Shuster, titled "Hot Melt Thermoplastic
Adhesive Foam System"; in U.S. Patent No. 4,059,714 to Scholl,
Janner and Stumphauser, titled "Ho-t Mel-t Thermoplas-tlc Adhesive
Foam System; and in the co-pendincJ appl.ica-tion of Cobbs and
Shong, titled "Method o Maki.ncJ Foamed Therrnoplclstic Mater.i.als",
Serial No. 300,20:L, fi:Led April 27, :L977, now Canadian Patent
No. 1,085,997, issued Septernber 16, 19~0.
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Briefly, as there descri.bed in detail, a foamed
hot melt adhesive may be created by intimately mixing air
or another relatively inert gas with -the thermoplas-tic ad-
hesive while the adhesive .is in the liquid stage, and then
pressurizing the liqu:id/gas mixture to force the gas into
solution with the liqui.d adhesive. The liquid adhesive is
subsequently dispensed at atmospheric pressure with the result
that the gas is released from solution and becomes entrapped
in the adhesive to form a homogeneous closed cellular ad-
hesive foam. When the hot adhesive foam is compressed or
squeezed between two substrates to adhere them, as when the
cover is applied to the book body, gas is forced from the
foam and the bond is formed between the two substrates.
As shown in Scholl et al U.S. Patent No. 4,0S9,714,
the foam hot melt adhesive system is a great improvement over
non-foam hot melt systems, in respect to open time, that is,
the time period.during which -the adhesive is sufficiently
fluid to be receptive for adhering a subs-tra-te. Non-foam hot
melts have a shor-ter open time, resulting from relatively high
viscosity, high surface tension, and quick setting -time, which
combine to prevent the adhesive from spreadi.ng over a large
surface area when the adhesive is applied as a liquid sub-
strate. Moreover, the adhesive streng-th of a bond achieved
; with a given hot melt adhesive is appreciably improved and in
most instances w.ill be doùbled i.f the adhesive is applied as
a cellular foam rather than as a conventional non-:~oam ad-
hesive.
Refer~nce ls also macle to the co-pendlny appl.icati.on
of Cobbs, Shong and Rehman titled "Foam Coating", Serial No.
313,320, fi.led October 1.3, 1978, which teaches techniques for
spraying hot melt foam. More specifically, that applica-ti.on
teaches techniques for formulatiny liquid compositions con--
taininy film-forming solids, including adhesives, then con-
- ~3 -
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veying them in a foam state toward the surface by spraying,
and upon foam disintegration, forming a film of solids on
the surEace.
It is a particular advantage of this invention tha-t
it may be used -to apply adhesive to a book body oriented in
the "spine up" orientation shown in Fig. 3, as well as the
"spine down" orientation shown in E'ig. 2, whereas prior tight
backing techniques utilizing glue wheels generally could be
carried out only in the spine down condition by reason of
difficulties in applying glue to a glue wheel located below
the pot. Where a bindery has associated equipment tha-t -treats
the book in the spine up condition, this versatility eliminates
any need for book inverting equipment, and -thus leads -to
saving in capital equipment and space.
In the binding operation shown in Fig. 2, the cover
14 is adhered to the body 10 by three adhesive bands or zones,
-these being the band 13 along the spine 12 and -the two narrow
; lines of adhesive 22 and 23 on the front and back of the book
adjacent the cover hinges.
; 20 At the join-t glue station 34, cover 14 in horizontalorienta-tion is carried by a conveyor past the nozzle 42 of a
hea-ted gun 43, fed by a hose 44. Gun 43 ~ay be si~ilar to
gun
- 14 -
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~ ~ ~'2 ~f3 ~ ~ I
.
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n 37 ~reviously described, and may be Eed froln the same source as
the nozzle 38 by which the coverincJ ylue is applied to the book
body. The joint glue lines 22 and 23 on cover 14 are generally ¦
~I quite narrow in comparison to the ~and 13 of adhesive on the I
¦¦ body spine; typically they may be of the order of about l/16 ~
I inch, and they can be extruded OlltO the cover. For that purpose
¦ gun 43 is fitted with an extrusion nozzle 42 havin~ two o~ifices
throuc~h which two separate streams are extruded; alternatively,
separate~ nozzles or evfln separate guns may be used, assuming
space permits. Alternativf-ly, however, the lines can be pro-
jected from a no7.z:le in accordance with -the inventio~.
Once the glue lines 22 and 23 have been applied to it,
il cover 14 is moved rapidly to the mating station 31, where it is
brought into engagement with body 10 -to which the primer and
,~ covering glues have already been applied, and is held in contact I ~l
l untll the adhesive has cooled and set. Machinery for such as- I ff
sembly is known per se.
A particular advantage of this invention is that it ¦
~ ~I provides especially improved results ln the application o
~1 adhesive to a book body having a spine that is rounded, as shown l'
¦l in Fiyure 3, rather than flat as in Figure l. In the past, when
hot melt glues have been applied by either glue wheel or multiple
bead extrusi.on techni(lues, it has been especially dl.fficult ~o
obtain uniform cover~ge on a splne which is arcuate or rounded, I ji
as is the spine desicJnated at ~5.
¦¦ Even if tlhe cJlue wheel'is made concavf~ in an attempt to ¦ '
Il match the round oE the spine, nevert:heless the curvature of the ! , !'
spines will vary -E~om book-to-book even in a given run, so ~ha-t
,. ~
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~ 1125~6~
I! ~ ~,
i` the wheel curvature will not fi-t all of them propexly. ~s a
result, adhesive is not applied uniformly and some areas
receive too Ill~lCh or -~oo little of the aclhesive. On -the other
hand, when the adhesive is applied by extruding i-t as multiple f
j parallel bands, the spacing between the spine and the extrusion
f nozzle difEers because oE the curvature and this ~eads to non-
uniform coverage with some zones not receiving enough glue. I ;
Moreover, the extruded lines may not flow together but instead
may remain as discrete ridges which "telegraph" through the
10~ ¦ cover spine. Irhe "~lat sheet" glue projection technique of
this invention overcomes these objections, ~ecause the sheet ¦~
¦ deposits as a uniform film all the way across the spine.
igure 3 illustra-tes an alternative process for
simultaneously applying a hot melt glue as a projected band 46
I ~ ~ along -the curved spine 45 of the book and as extruded lines, one
! f which is shown at 47, on the sides or faces of the booX. ;~
I As shown, a common source of the adhesive, including a melter
I and pump unit 48, may be used to supply all three nozzles, i.e.~,~ ff. `
f' the flat fan nozzle 49 and the side band applying noz21es 50 and~
20 ~ ' S1, through heated hoses and guns as prevlously described. A
¦ flat shee-t of adhesive 53 is applied from nozzle 49, whereas the
beads 47 may be extruded from the nozzles 50 and Sl. The hook ;~
body may be conveyed by conventional mechani.sm past th~ no~zle~s I ~ f, ,`''l
in the directi.on indicated by the arrow M~, wlth -the actuation
of th~ throe no~zleo oontrol.led by R timer, photo~ell, or the lLk~.
-16~
il The followiny example ls yiven -to illustrate the
~ application o~ ho-t melt foam in accoxdance with the invention,
¦ in one specific instance: Eastman type A3 hot melt adhesive
I previously described was formed in accordance with the teaching
/~ I ~/.S. '~.
i f Patent No. 4,059,744. It was sprayed through a ribbon nozzle
Ij of the type shown in Fiy. 4, at a temperature of 350-375 F
i 1 under llOO psi onto a rrloviny substra~e. The noæ~le to substrate
¦ spacing was abou-t 2 inches; the orifice width was 1~2", and the
~ ¦ adhesive deposited as a continuous flat thin foam band of about~ ~
lO~ ¦ 3" width. The band was slightly thicker along its outer;edges, ~ S
~1 I and was very slightly thicker midway between the outer edges, I ¦ ~ ~;
¦ but these minor vaxiations in thickness would~not be detrimental
in binding. ¦~
While the invention has been described hexein with
~ ~. . i - ~: :
particular xeference to a preferred me-thod and apparatus~, it lS; ~ `.` ;~
not limited to those embodiments, but includes other variations I j 1
¦ and modificatlons within the scope of the following claims.
'~ I
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