Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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GLUED LAMINATED WOOD AND METHOD OF MANUFACl'URING
T~IE SAME.
Fiel~ of the invention
The present invention relates generally to yluea
laminated wood, including plywood and to a method of manu-
facturing the same. More specifically, it re]ates to
glued laminated wood having a novel laminated structure
of veneers and to a method of manufacturing the same.
Background of the invention
In the so-called improved woods, several types
of sheet or board materials are available, among which
glued laminated wood, including plywood is one of the most
popular wood sheet materials.
In general, glued laminated wood which is composed
of plural layers of veneers laminated or glued together into
a sheet form achieves its thickness from the thicknesses of
the individual component veneers and the number of layers
of such component veneers. Such glued laminated wood,
including plywood, as compared with sawn lumber, exhibits
improved uniformity in strength and provides a useful wood
sheet material which can be made in much larger areas.
Therefore, such glued laminated wood, including plywood
comes in a great variety of sizes and thicknesses, and can
be laminated in different ways to meet varying requirements
of the marke~. It is therefore used for a wide range of
applications including, construction, housing, furniture, e-tc.
Under present circumstances of limited supply and
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therefore increasing prlces of logs, it is an uryent task
of every manufacturer to establish a manufacturing system
which can permit production of various kinds of glued la-
minated wood sheets or panels having different lengths,
widths and thicknesses with the highest possible yield
rate and the minimum cost in production, labor and materials,
in order to fulfill the above-said versatile demands of -the
market. In addition, it is a potential task of the producer
to develop new fields of application for such glued lamina-
ted wood through further improvements of its inherent advan-
tages.
It is evident that the above~mentioned urgent pro-
blems cannot be solved by glued laminated wood having con-
ventional structure which inevitably calls for and requires
selection of component veneers whose sizes are determined
by the si~es of the glued laminated wood sheets or panels
to be mada. For e~ample/ it is presently necessary to cut
veneer sheets from a log which is eight feet long in order
to make a typical 4' x 8' plywood panel, for reasons under-
stood by those familiar with the manufacture of plywood.
This requirement makes conventional plywood panels more costly.
~t is therefore believed that an effective approach to the
problem would be -to establish a technology by which various
sizes of glued laminated wood, including plywood may be
fabricated from veneers of a reduce~ number of sizes or,
most preferably, from veneers of only one size. Moreover,
it would be a significant advance if glued laminated wood
panels could be manufactured fr~m veneers which are smaller
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than the intended panel si~e. ~n other words, the pre-
sent invention is intended to provide more effective
utilization of veneers. This is because, iTI the manufac-
ture of glued laminatecl wood, the process involved in
makiny veneers from logs is more problema~i.c and calls
for more labor than does the process of making the lami-
nated wood from the veneers. ~hus, improvements in the
former process can make a greater contribution to the
reduction of costs and to the simplification of laminated
1~ wood manufacturing as a whole~ However, when realizing
a plywood technolog~ which could make possible production
of various plywood sizes from veneers of a reduced nu~er
of veneer sizes or of a single size, it would be important
to prevent the introduction of any new defects in the pro-
1~ ducts which would be made in that way. The glued laminated
wood and the method for its manufacture according to the
present invention were developed with these considerations
n mind.
Japanese Patent Application No. 104006 (1976~ pu-
blished on September 14~ 1976 to Ishida shows glued lami-
nated wood composed of a series of short veneers which
are all parallel-laminated in such an arrangement that
each.veneer is offset or shifted with respect to its ad-
~acent veneer at a regular interval of leng-th, and the
2~ ends of all of the veeners are exposed on both faces of
the sheet. However, the glued laminated wood product o-f
the present invention is different, and is produced in a
different way.
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~t is an object oE the present invention to provi-
de glued laminated wood which has improved ven~er lamina-
tion and is economical to manufacture.
~t is another object of the invention to provide
S glued laminated wood which, when its length and width are
given, can be made from veneers whose lengths and/or widths
are smaller than those of the glued laminated wood to be
made.
It is another object of the invention to provide
glued laminated wood which can be made longer without being
influenced by the given length and/or width of the veneers
therefor.
It is still another object of the invention to pro
vide glued laminated wood which can be made in many sizes
or dimensions from veneers whose number of sizes or dimen-
sions is reduced.
It is still another object of the invention to pro-
vide glued laminated wood which can be made in various
forms of veneer lamination.
It is still another ob~ect of the invention to pro-
vide glued laminated wood which, after forming, is accep-
tahle in appearance and can be used without further pro-
cessing.
It is another important object of the present in-
~5 vention to pro~ide a method of manufacturing the glued
laminated wood product contemplated by the invention.
It is still another object of the invention to pro-
vide a continuous method of gluing and laying-up of veneers
~, in making oE the glued laminated wood which has distinct
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labor saving advantages.
BrieE d~scription o~ the Invèntion
The foregoing objects are attained by providiny
a continuous run of laid-up veneers which is made from
S a series ot unit-length veneer sheets having the same
length and laminated in a laid up arranyement in which
each veneer sheet is lapped on another and offset there~
from in the direction of its length at a reyular interval
determined by the number of plies to be in the glued la
minated wood and the length of the unit veneer sheets.
The layers of veneers thus arranged are tacked, and glued
laminated wood panels of one or more desired sizes are
produced by ~utting such a continuous length of laid-up
veneers into the desired lengths and then pressing the
lS cut lengths to maka the exposed surfaces of the veneer
sheets flush with ea~h other. Alternatively, depending
upon the arrangement and the type of hot press for forming
glued laminated wood, an indefinite and substantially con-
tinuous length of glued laminated wood from which panels
of the desired lengths may be Cllt, can be produced.
The gl~ed laminated wood, including plywood thus
produced has a novel structure in that each veneer sheet
therein has tandemly spaced straight length portions which
are parallel to each other, but successively displaced
from each other in the direction of the thickness of the
glued laminated wood, there being a somewhat S-shaped
curved length portion of the veneer sheet between any
s~lccessive pair of these straight length portions. The
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extent of the referred to displacement of each successive
straight length portion is equal to the thickness oE the
adjacent veneer sheet, and the number of such straight
length portions in each veneer sheet i5 e~ual to the number
of plies or veneer laminations in the glued laminated wood
being made. The length of each such straiyht length por-
tion is nominally determined by dividing the length of
the unit veneer sheet (measured in the direction of forma-
tion of the laminated wood) by the number of plies. ~hus,
the endmos~ straight length portions of each veneer sheet
will respectively appear on the opposite faces of the laminated
wood product and form a portion of such faces.
The unit-length veneer sheets are substantially
flat when the necessary glue is applied to their overlapping
length portions and they are laid-up in the afore-mentioned
successively lapped relation. It is apparent that all of
the veneer sheets will be inclined to the horizontal and
will cxtend across the thickness of the laid-up arrangement
thereof. Preferably, the unit-length veneer sheets are
laid up ~ubstantially in a continuous manner, which is
followed by a tacking operation for temporarily laminating
the glued plies of veneer sheets together. After tacking,
panels of laminated ~eneer sheets of any selected sizes
are cut fro~ the continuous lamination of veneex sheets,
and the individual panels are then hot-pressed to cause per-
manent formation of the afore-mentioned straight length
and curved length portions in each laminated veneer sheet
to produce a flattened thickness in the glued laminated wood
panels and also for curing the lamination glue, thereby
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to fix the shapes of the veneers therein.
In i~s preferred embodiment~ the invention ~urther
contemplates a continuous manner of application of glue
to each veneer sheet, before it is laid-upl b~ which those
areas on the sheets which will appear on the faces of the
glued laminated wood are automaticall~ shielded from the
glue application, yet the glue is applied to all of the
areas on which it is intended. This is accomplished by
arranying a single row of the veneer sheets in lapped
relation on a flight conveyor, preferably located above
the main laying-up conve~or and which travels ln the oppo-
site direction, and appl~ing the glue by a glue spreader
along only the top surfaces of the lapped sheets. The
unit veneer sheets with the glue thus applied are then
successively dropped on~o the main conveyor in their in-
tended laid-up arrangement, as will be seen.
After the glued laminated wood panels have been
formed, filler material ma~ be applied to fill in the na-
turall~ occurring grooves adjacent the ends of the veneer
sheets to smooth one or both faces of the panel. Alter
natively, a conventional panel-si2ed veneer sheet overlay
may be laminated onto one or both faces, whereupon the
pane~s will have the appearance of conventional panels.
Still another alternative would be to avoid the formation
of such grooves by beveling one or both ends o~ each veneer
sh~et before forming the laminated wood, as will be seen.
Detailed Description of Preferred Embodiments
These and other objects, features and advantages of
,
the inven-tion will become apparent to those s~illed in
the art from the following descriptlon of the basic
structure of pl~wood and ~arious embodiments of ylued
lamina-ted wood according to the present invention, and
methods for its manufacture, which description is made
with reference to the accompanying drawings, wherein:
Fig. 1 is a fragmentar~ perspective view illustra-
ting the basic laminated structure of veneers as it ap-
pears in glued lamina-ted wGod according to the invention;
Fig. 2 is similar to Fig. 1, illustrating the same
basic laminated structure of veneers in the glued lamina-
ted wood of the invention, but wherein the veneers have
beveled ends for providing uninterrupted surfaces on the
plywood;
Fig. 3 is a fragmentary side view of glued lamina-
ted wood of the invention, showing a manner of veneerlamination which is slightly different from that of Fig.
Figs. ~ to 7 are fragmentary side views showing
other possible end forms of each veneer and laid-up arran-
gements of such veneers;
Fig. 8 is a partial perspective view showing a ty-
pical unit veneer sheet which is used as a component ve-
neer for fabricating glued laminated wood panels in accor-
dance with the invention;
~S Fig. 9 is a partial perspective view showing a pa-
rallel laminated wood panel according to the invention
produced using unit veneer sheets as illustrated in Fig. 8;
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Fig. 10 is similar to Fig. 9, but showing another
embodiment of a parallel laminated wood panel produced
using unit veneer sheets having beveled ends;
Fig. ll is a par-tial perspective view showing ano-
ther unit veneer sheet which is used as a component veneerfor making glued lamina*ed wood panels;
Fig. 12 is a partial perspective view showing the
embodiment of a parallel ~aminated wood panel produced
using unit veneer sheets as illustrated in Fig. 11;
Fig. 13 is similar to Fig. 1~, but showing another
embodiment of a paxallel laminated wood panel produced
using unit veneer sheets similar -to that of Fig. 11, but
having beveled ends;
Fig. 14 is a fragmentary perspective view of a unit
vPneer sheet which is made using two veneer sheets jointed
together;
Fig. 15 is a partial perspective view of the embo-
diment of a glued laminated wood panel of the invention
produced using -the unit veneer sheets as illustrated in
~Q Fig. 14,
Fig. 16 is similar to Fig. 15, but showing another
embodiment of a glued laminated wood panel produced using
unit veneer sheets similar to that of Fig. 14,but having
beveled ends;
Fig. 17 is a partial perspective view of a unit
veneer sheet which is made using three pieces of veneers
jointed together;
Fig. 18 is a partial perspective view showing the
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embodiment of a glued laminated wood panel of the inven-
tion prod~lced using unit veneer sheets as illus-trated
in Fig. 17;
Fig. 19 is similar to Fig. 18, but showing another
S embodiment o~ a glued laminated wood panel produced using
unit veneer sheets similar to that of Fiy. 17~ but having
beveled ends;
Fig. 20 is a partial perspective view showing ano-
ther unit veneer sheet which is made using three pieces
of veneers jointed together;
Fig. 21 is a partial perspective view showing the
embodiment of a plywood panel of the invention produced
using a plurality of the unit veneer sheets shown in Fig.
20;
Fig. 22 is similar to Fig. 21, but showing another
embodiment of a glued laminated wood panel of the invention
produced using unit veneer sheets similar to that shown in
Fig. 20, but having beveled ends;
Fig. 23 (A) and (B) are partial perspective views
showing res~ective, alternate grain arrangements in unit
veneer sheets made of two pieces of undersized veneers
~ointed -together;
Fig. 24 is a partial perspective view of the embo-
diment of a glued laminated wood panel of the invention
produced by laying up alterrlate unit veneer sheets as
shown in Figs. 23 (A~ and (B);
Fig. 25 is similar to Fig. 24, but showing another
embodiment of a glued laminated wood panel produced in
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the sarne manner as that of Fig. 24, bu-t wherein the uni-t
veneer sheets have beveled ends;
Fig. 26 is a schema-tic illustration o~ pr~ferred
method of manu:Eacturing the aforesaid embodiments of ylued
laminated wood panels, including plywood panels, accordiny
to the invention;
Fig. 27 i5 an enlarged sectional view of veneers,
showing possible variations in the relative lapped positions
of one veneer sheet on another during the laying-up step
in the glued laminated wood manufac~uting method illus-
trated in Fig. 26;
Fig. 2~ is a similarly enlarged sectional view of
veneers r showing possible variations in the relative lapped
positions of one veneer sheet on another during the gluing
step in the glued laminated wood manufacturing method il-
lustrated in Fig~ ~5;
Figs. 29 and 30 are partial perspective views, res-
pectively~ showing alternative types of flight conveyors
which may be used to convey the unit veneer sheets during
the gluying and laying-up steps in manufacturing the glued
laminated wood panels according to the method illustrated
in Fig. 25;
Fig. 31 is a schematic diagram illustrating the ope-
rative relationships between the conveyor drives used in
~S the gluying and laying-up processes;
Fig. 32 is a fragmentary perspective view of glued
laminated wood in accordance with the invention having
overlay sheets adhered to its respective faces; and
Fig. 33 is a diagramatic illustration o~ the manner
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of cutting unit Veneer sheets ~rom random lenykh logs,
for use in practicing the present invention.
Referring first to Fig. 33, thexe is illustrated
a conventional manner of producing a continuous lenyth
of venee.r sheet V from a log 40 by forced rotation of
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the log in the direction of axrow ~, against the knife
blade Y, causiny the veneer V, having a thickness t,
to peel off in the direction of arrow Z. The wood grain
G extenas in the direction of the length of khe log 40,
as is well understood.
When making a conventional glued laminated wood
panel (.not shown~, the length of the panel is limited
to khe length o~ the log 40; e.g., a 4I x 8' pl~wood panel
calls for a log whose length is at least 8', which means
that a veneer-lathe which is capable of handling at least
8' long logs has previously been necessary for making such
4' x 8' panels. According to the present invention, how-
ever, any sized panels can be produced from a plurality
of unit veneer sheets, such as the unit veneer sheet 3
shown in Fig. 8 whose length is indicated b~ Ll and its
width W. The width of the panel -to be made is determined
by cutting the veneer V (Fig. 33) peeled from the log 40,
into a width W, in this case 4'. On the other hand, since
the series of ~nit veneer sheets 3 are laid~up and lamina-
ted success.ively in the direction Ll (Figs. 8 and 33),
the glued laminated wood panel can be made as long as any
req~ired dimension, say 8'. In this way, the 4' x 8'
panel can be produced from a log 40 whose length does not
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l~ve to be at least 8' ~ong, but may be much smaller than
that, say only 3' long.
Turning now to Figs. 1 and 2, the basic laminated
structure of venears glued toge-ther to form glued lamina-
ted wood according to the present invention is illustra-ted
wherein the glued laminated wood, though it is shown only
in a partial view, is designated by reference nu-meral 1,
and veneers constituting the layers or plies of such glued
laminated wood 1 are indicated by reference numeral 2.
For clarity of understanding, no wood grain pattern is
shown on th~ laminated wood product in Figs. 1 and 2.
The present invention contemplates the production
of glued laminated wood, having any desired finite length,
which.may be obtained from a potentially continuous length
of laminated wood formed by a series of relatively small-
$ized ~nit-length ve.neer sheets laminated in a regular
manner so as to form such continuous length of glued la-
minated wood. For convenience in describing the structure
of glued laminated wood according to the pres~nt invention,
the veneer lamination structure of the product will be
explained herein on the assumption that the glued lamina-
ted wood which is partially shown in FigsO 1 and 2 (and
also in other similar drawings illustrating individual
different embodiments) constitutes a fragmentary showing
of either the finished, cut glued laminated wood panel
or the glued laminated wood as formed in a continuously
extending len~th from which the plywood panels may be cut,
because the shapes of the veneer laminations are the
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same in both.
Referring to Fig. 1, -the glued laminated wood in
accordance with the invention is formed b~ laminatiny a
series of unit veneer sheets 2, each haviny the same
thickness t and the same length L. In the illustrated
embodiment, the~v are built up into a Eive ply of five-
layer configuration, as most clearly seen at the cut-
away end section of the illust~ated glued laminated wood 1.
In making the glued laminated wood, a series of such unit
veneer sheets 2 are laminated tc~gether in a laid-up arran-
gement so that each of the veneer sheets 2 is partl~ su-
peximposed, or lapped, on another veneer sheet 2 positioned
in an adjacent layer, the upper sheet being offset from
the other, i.e., having its one end spaced from the cor-
respondingly adjacent end of the underlying sheet, at alength interval Q Thus, the successively laid-up unit
veneer sheets 2 may form an indefinite, continuous length.
Wh.en such a lai.d-up arrangement of veneer sheets 2 is
pressed flat, each veneer sheet is deformed, and displaced,
or stepped in the direction of the thic~ness T of the
laminated wood, at the same regular intervals Q, at the
locations corresponding to the ends of the successive
veneer sheets. As will be seen, each succesive veneer
sheet if offset from each other at the same interval Q,
and it will be noted that each component veneer sheet 2
thus deformed .includes respective straight length portions
la forming portions of the opposite faces of the laminated
wood product, and straight length portions lb extending
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parallel thereto in tamdem relation and successively
displaced from each o-ther in the direction of the thick~
ness T of the procluct. Between each pair o straiyht
leny-th portions a generally S-shapecl, curved length
portion lc is formed comrn~nsurately. A finished glued
laminated wood panel having any desired length may be
obtained by cutting such substantially continuous length
of the laminated wood.
In the continuously extending glued laminated
wood having a preselected number N of veneer plies and
composed of veneer sheets 2 each having a longitudinal
dimension L which are offset at length intervals Q, the
relationships between N, L and Q, may be formulated such
that L is substantially e~ual to the product of N and Q,
i.e., L_NQ. The lapping distance or lapped leng-th portion
of each veneer sheet 2 is therefore expressed as L -L/N.
In order to ensure consistency in the number of veneer plies
the glued laminated wood 1 for attaining substantial uni-
formity in the product thickness throughout its length~
the component veneer sheets 2 should be offset when lapped
on each other at such regular intervals that the leading
end 2a of any veneer sheet 2 on one face of the product
and the trailing end 2_ of a veneer sheet 2 exposed on
the other face thereof are positioned in oppositely aligned
2S relation to each other across ~he thickness _ of the pro-
duct, as exemplified in Fig. lo Therefore, consistency
in the number of veneer plies in the laminated wood 1 is
assured by predetermining the value for Q correctly with
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relation to the desired number N of veneer plies and
the length L of each component veneer sh~et 2 or, alter-
natively, by predetermininy the value for L with re~ation
to _ and ~. As a concrete e~ample, when glued laminated
wood of five-ply configuration ~N=5) is to be made from
veneer sheets each having a length of 300 mm (L=300), the
offsetting length interval Q will be about 60 mm (or300/5).
It will now be apparent to those skilled in the art, to
increase the number of veneer plies in the glued laminated
wood 1, the value for L i5 increased and/or the value for
Q is decreased accordingly; and that, to decrease the
number of plies, the reverse is true.
In the glued laminated wood of Fig. 1 whichis com-
posed of veneer sheets 2 whose ends are square-cut, re-
cessed portions R will inevitably be formed extending
-
across the width of the product on both faces ld, l_
thereof at locations which are spaced at intervals corres-
ponding to the lengths Q. Such recesses may be left as
they are without any additional processing if so desired,
e.g. for any particular appearance effect, although they
may be easily eliminated by applying filler material therein.
Alternatively r additional grooves may be form~d so as to
camouflage the original recesses.
Referring now to Fig. 2, the glued laminated wood 1
is fabricated substantially in the same manner as the glued
laminated wood of Fig. 1, but the component unit veneer
sheets 2 for its lamina-ted construction are provided at
their ends 2a, 2_ ~ith bevels formed by scarf-cutting or
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any other convenient process. The results j.s -th~t the
glued laminated wood 1 made from such beveled veneer
sheets will have complete fla-tness without the referred
to recesses R ~Fig. 1) on both ~aces thereof. When vene~r
sheets '~ having such beveled ends are used for lamina-tion,
however, it is important that each sheet 2 be accurately
overlapped so that the beveled faces of each pair of opposed
ends 2a, 2_ on the opposite faces of the product overlap
each other with reference to ~heir sectional alignment,
as shown in Fig. 2, to achieve complete flatness without
aither recesses or projections on the product faces. In
such a case, if the length L of each component veneer sheet
2 for the glued laminated wood of Fig. 2 is the same as
that of Fig. 1, the length Q of the veneer offset intervals
should be slightly smaller in Fig. 2 than in the case of
Fig. 1, because the membars of each pair of opposing beveled
ends 2a, 2b extend beyond each other for a slight distance,
as will be understood.
It should be noted here in connection with the afore-
mentioned relation of Q~L/N that in the glued laminated
wood of Fig. 1 each pair of the adjacently opposite ends
2a, 2_ are preferabl~ positioned with some longitudinal
spacing bQing provided in the sectional alignment between
the extreme ends thereof, whereas in the glued laminated
wood of Fig. 2 each pair of the adjacentl~ opposite beveled
ends 2a, 2b is in fully overlapping relation to each other.
Thus, the value for Q varies from case to case even if the
-
values for _ and N remain the same. In addition, although
the length L designates the longitudinal dimension of each
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component veneer sheet 2 in a straiyh~ened states, the
actual ~alue Eor L as measured in the longitudinal di-
rection of the formed laminated wood will be sliyhtl~
smaller. Thol1gh there actually exists a slight de~iation
from the relationship ~ , it will be understood, having
the features of the laminated wnod structure of the inven-
tion in mind, that such deviation is considered to fall
within the scope of the formulation Q-L~N.
Reference is now made to Figs. 3 to 7 showing va-
rious examples of the shapes of the veneer ends, and re-
lative alignment relationships of the oppositely disposed
respective ends 2a, 2_ on opposite faces of the laminated
wood.
Referring to Fig. 3 which shows in siae elevation
lS a portion of the glued laminated wood 1 having five plies
of veneer shee~s 2 laminated together 7 each veneer sheet
2 has square-cut ends and is lapped on another using an
offset interval such that the opposed ends 2a, 2b extend
beyond each other for a slight dist~ce, with the result
that o~twardly proje~ting portions are formed on both faces
of the laminated wood. Of course, when the laid-up veneer
sheets are pressed to deform the laminations, the faces
of the press accommodate these projections, as will be
understood. These projections on the laminated wood may
2~ be left as they are if so dèsired, but may be removed
readily by sanding or cuttiny, as indicated by phantom
lines, for prod~cing substantially flat surfaces on the
product faces.
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Figs. 4 to 7 show six plies of veneer shee-ts 2,
respectively, which are just laid~up and are yet to be
glued together to form the complete laminated wood prod-uct.
In Fliy . ~ r each veneer sheet 2 has beveled encl~ with their
beveled faces facing inwardly. ~'he ends 2at 2b are posi-
tioned in overlapping relation as illustrated, so that
their beveled faces extend beyond and face each other~
Glued laminated wood obtained by pressing these six plies
of veneer sheets 2 to cause the aforementioned deformation
1~ thereof is similar to the glued laminated wood of Fig. 2,
though the latter is only of five-ply structure. Fig. 5
shows six plies of veneer sheets 2 each of which has beveled
ends whose beveled faces, unlike the counterparts of Fig. 4,
face outwardly. Glued laminated wood resulting from such
~S layers of veneer sheets 2 after pressing is similar to the
glued laminated wood of Fig. 3 after removal of the excess
material from the ends as previously described. In Fig. 6,
one end of each veneer sheet 2 is beveled while the other
end thereof is square-cut, and each such veneer sheet is
placed so that the ends 2_, 2b are substantially in verti-
cal alignment with each other at their extreme ends.
Accordingly, after the veneer sheets 2 are deformed for
laminating them into the glued laminated wood product, one
face thereof will be formed flat while the other face will
be formed with recessed po~tions -therein. In Fig. 7, each
component veneer sheet 2 has ends 2a, 2_ which are chamfered
or rounded, and which are spaced longitudinally apart on
the opposite faces of the product, with reference to an
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imaginary line (not shown~ extending perpendicular to
its thickness. The resulting glued laminated wood will
have recesses on both faces thereo-E, and the exposed
edges of each veneer sheet 2 will be rounded, accordinyly.
S Further embodiments of the glued laminated wood of
the invention will now be described with reference to E'igs.
8 - 25.
Fig. 8 shows a unit veneer sheet 3 having a longi-
tudinal dimension Ll in the direction of its wood grain G.
A series of such unit veneer sheets 3 are laminated toge-
ther in the above-described manner for ~uilding up glued
laminated wood, from which laminated wood panel 4 of the
embodiment shown in Fig. 9, having a five-~ply configuration,
may be obtained~
In the embodiment of plywood 4 shown in Fig. 9, it
is fabricated by parallel-laminating a series of the unit
veneex sheets 3 of Fig. 8, with all of their grains G ex-
tending in the longitudinal direction of the laminated wood
to be made. ~herefore, each unit veneer sheet 3 will be
offset in the direction of its wood grain from each adja-
cent veneer at an interval of predetermined length Q l,
so as to form a continuous length of parallel laminated
wood. A panel 4 of any des~red length may be cut from
such continuous length of glued parallel laminated wood.
The faces of the laminated wood ~ inevitably have
recesses R formed therein adjacent to the ends of each
veneer sheet 3, but these may be eliminated by applying
any suitable filler material therein. If desired for any
reason, such recesses may be retained as they are, without
~2~
-21-
any further additional processing, or additional grooviny
may be provided so as to camouflage the recesses. Though
the veneer sheet 3 in Fig. 8 is shown as a solid sheet,
it may contain therein one or more joints 3a at which -two
pieces of undersized veneer sheets are end-jointed to
ma~e a full-si~ed unit veneer sheet having the length Ll,
e.g. when it is desired to use veneers which are shorter
than Ll. Such joints may be formed easily by using any
known method such as butt-jointinyr scarf jointing, or
an~ other convenient jointing.
Another embodiment of the glued parallel laminated
wood 4 as shown in Fig. 10 is similar to that of Fig. 9,
but differs therefrom in that the laminated wood is composed
of veneer sheets 3 whose ends are beveled in the inwardly
facing direction, thus corresponding to Fig. 2. This em-
bodimen-t is advantageous as compared with its counterpart
in Fig. 9, when continuity in surface flatness is a major
concern in product quality~
Reference is now made to Fig. 11, wherein a unit
veneer sheet 5, having the dimension L2 across its wood
grain G is shown. A series of such unit veneer shee-ts 5
are used to fabricate a substantially continuous run of
glued parallel laminated wood from which laminated wood
6 of any required length as shown in Fig. 12 may be cut.
~n the embodiment of ri~. 12, the parallel laminated
wood 6 is made by laminating a series of the unit veneer
sh~ets 5 of Fig. 11 in parallel relation to each other
with all of their grains G extending across the longitu-
- 22 -
nal direction of the product. Accordingly, each unit
veneer sheet 5 will be offset, in the direction across
the wood grain thereof, from each adjacent veneer sheet
at a predetermined length in-terval Q2 for forming a con-
tinuous length of glued parallel laminated wood. Thelaminated wood 6 of any desired length ma~ be obtained
from such continuous length of parallel laminated wood.
Fig. 13 illustrates another embodiment of the glued
parallel laminated wood 6, which is made using a series of
laminated unit veneer sheets, 5 having beveled ends as in
previous embodiments for preventing recesses from being
produced on the product faces.
Referring to Fig. 14, a unit veneer sheet 7 is
shown which, ~nlike the solid unit veneer sheets shown
in Figs. 8 and 11, includes two pieces of undersized
veneers 8 and ~ which are jointed together along their
line of abutment 7a to make the full-sized unit veneer
sheet 7 having a longitudinal dimension L3. The under-
sized veneer 8 on the left-hand side as shown has it grain
Gl oriented in the longitudinal direction of the laminated
wood to be made; while the other undersized veneer 9 has
its grain ~2 thereacross. When making a unit veneer sheet
7 which includes two jointed pieces of undersi~ed veneers 8
and 9, the dimension of the veneer 8 in the direction of
its grain Gl and the dimension of the veneer 9 across its
grain _2 should preferably be such that either of the di-
mensions is greater than the interval lengths Q3 (Figs.
lS and 16) at which the unit veneer sheets 7 will be offset
~ , ,
~'
~2~a~2
- 23-
successively from each other in the lamination thereof
for ma~ing of the laminated wood product~ ~y ~o doing,
the abutment line 7_ may be prevented from appea.ring on
the product faces. Furthermore, to maintain the s-trength
of the res~llting laminated wood the climension of the ve-
neer 8 having its grain Gl along the length L3 should
preferably be the sum of said interval length Q3 and a
dimension which is greater than five times, or more pre-
ferabl~ in the range of from 15 to 150 times, the thickness
of the veneer sheet 7 so that the jointing line 7a may
not be positioned closely enough to the adjacent lapping
end of its overlying veneer sheet to affect the strength
of the laminated wood at such jointing line, as will be
understood by those skilled iIl the art.
When a series of overlapped veneer sheets 7 having
thçrein a side-to-end ~oint are glued together to form a
laminated struc~ure according to the invention, glued la-
minated wood 10 as shown in Fig. 15 will result. That is,
in the illustrated case of a five~ply laminati~n, the
upper two or three plies thereof have their grains Gl
extending in the longitudinal direction of the glued la-
minated wood 10, while the lower two or three plies have
their grains G2 set thereacross.
The embodiment of plywood shown in Fig. 16 differs
from that of Fig. 15 in that the glued laminated wood is
made of similar unit veneer sheets 7, but each having its
ends beveled in the inward direction, each unit veneer
sheet being offset from another at a slightly smaller
~ a,
- 24 -
interval, as previousl~ explained.
Fig. 17 shows still another Eorm oE a component
unit veneer sheet 11 which is integrally formed by jointiny
three sections of undersi~ed veneers 12, 13 and 1~/ along
their respective lines of abutment lla, llb into a unit
veneer sheet 11 having a longitudinal dimension L~. In
this unit veneer sheet 11, its respective end sections 12
and 14 have their wood grains Gl extending in the direction
oE the length L4, whereas the veneer section 13 at the center
has it grain G2 extending thereacross. Each of the dimen-
sions of the undersized veneers 12 and 14 in the direction
of their grains G2 is made greater than the interval lengths
Q~ (Figs. 18 and 19) at which the unit veneer sheets 11
will be offset from each other when laminated to make the
glu~d laminated wood product. Furthermore, -the dimensions
of said veneers 12 and 14 should preferably be the sum of
said interval length Q4 and a dimension which is greater
than five times, or more preferably in the ran~e of from
S to 150 times, the thickness of the veneer sheet 11, Eor
the same reasons stated previously in connection with Fig.
14.
Laminating a series of such integrally formed unit
veneer sheets 11 o~ Fig. 17 into a five-ply structure ac-
cording to the invention will eventually produce glued
laminated wood 15 as illustrated in Fig. 18. In this em-
bodiment, a cross-banded structure which is similar to a
three-pl~ conEiguration can be created, as seen clearly
at the side section thereof. That is, in the case of the
6~
- 25
ill~strated five-ply lamination, one or two plies o -the
veneer she~ts 11 at the top and at the bottom of the ylued
laminated wood 15 have their grains Gl extendiny in the
direction of the length thereof, and two or three plies
at the core portion of the laminated wood have their yrains
G2 running thereacross.
-
The embodiment of the glued laminated wood 15 in
Fig. 19 differs from its counterpart shown in Fig. 18 in
th~t each component unit veneer sheets 11 therefor has
10 beveled ends, and is offset from each of its adjacent ve-
neer at a slightly smaller interval which corresponds with
the beveling as previousl~ explained.
In Fig. 20, a unit veneer sheet 16 is shown which
has th~ree sections of undersized veneers 17, 18 and 19
lS jointed together, along respective abutment lines 16a, 16b,
into the length ~5 of a full-sized unit veneer sheet 16.
This veneer sheet 16 is similar to that shown in Fig. 17,
but differs therefrom in that the undersigned veneer 18
at its center has its grain Gl extending in the direction
20 of the length L5, whereas the veneer sections 17 and 19
at the ends have their grains G2 extending thereacross.
Like the veneer sections 12 and 1~ ~Fig. 17), the under-
sized veneers 17 and 19, as measured along the length L5
or across the grains G2 thereof, have dimensions greater
than the length Q5 (FigS.21 and 22) of the intervals at
25 which the unit veneer sheets 16 will be offset from each
other in the lamination thereof into a continuous length
of glued laminated wood for the same reason stated in
. .
- 26 -
connection with Fig~ 14.
The glued laminated wood 20 which results from la-
minating such integrated unit veneer sheets 16 accordiny
to the invention is shown in Fig. 21. ~ts cross-banded
structure is arranged in a manner similar to that of the
embodiment of FigO 18, althollgh each veneer la~er is re~
versed in respect of the direction of i~s wood grains.
Fig. 22 illustrates another embodiment of the glued
laminated wood 20, wherein the ~aces thereof are formed
1~ flat, with no recesses such as those seen in Fig. 21, by
providing inwardly beveled ends on each component unit veneer
sheet 16, and laminating the veneer sheets with their ~e-
veled ends o~erlapping and confron-ting one another, as
previously explained.
Reference is now made to Fig. 23 which shows two
unit veneer sheets 21 and 24, each having two sections of
undersized veneers 22, 23 and 25, 26 respectively, which
are jointed together at the lines of abutment 21a t 24a
into unit veneer sheets having the length L6, respectively.
In the unit veneer sheet 21, its undersized veneer 22 has
its grain Gl extending in the direction of the length L6,
and the other veneer 23 has its grain G2 extending there-
across. ~ith reference to the unit veneer sheet 24, its
undersized veneer 25 has its grain G2 extending across
the length L6 and the other veneer 26 has its grain Gl
therealong~ The dimensions of the respec-tive undersized
veneers 22~ 23, 25 and 26 as measured along the length
L6 are preferabl~ made greater than the length ~6 (Figs.
$~2
- 27 -
24 and 25) o~ the intervals a-t which the unit veneer
sheets 21 and 24 will be offset from one another in the
lamination thereof when making a continuous le.nyth of
glued laminated wood so that the abu-tment lines 21a and
24a may not appear on the faces of the resulting product.
As to the veneer sections 22 and 26 having their grains
Gl extending along the length L6, the dimensions thereof
along the length L6 should preferably be the sum of said
interval length Q6 and a dimension which is greater than
10..' five times, or more preferabl~ in the range of from 15 to
150 times, the thickness o the veneer sheats 21, 24, to
avoid a decrease in strength of the resulting product due
to the abutment lines 21a and 24a being formed close to
the adjacent lapping ends of the successive overlying unit
~ veneer sheets in the laminated wood structure. In the
i.llus.tration of Fig. 23, the two unit veneer sheets 21 and
24 are made substantiall~ s~mmetrical with respest to the
~ointing lines 21a and 24a, respectively.
The glued laminated wood 27 which is made from the
combination of the above two kinds of unit veneer sheets
21 and 24 is exemplified in Fig. 24~ In this parti.cular
embodiment, the unit veneer shee~s are arranged and laid~
up in the ratio of two of the veneer sheets 21 to one of
2~ the veneer sheets 24, whereby glued laminated wood having
a composite cross-banded structure is created, as seen at
the side section thereof in Fig~ 24. Though not shown in
the drawings, various embodiments of laminated wood having
~he ~nit veneer sheets arranged in ratios other than the
, ~,,
q~2
- 28 -
above two-to-one, e.g. one veneer sheet Zl to any desired
number of veneer sheets 2~, three veneer sheets 21 to
any desired number of veneer sheets 2~, and so ~orth, may
be contemplated.
Fig. 25 exemplifies another embodiment which is si-
milar to that of Fig. 24, but whose component uni-t veneers
ha~e inwardly beveled ends, as shown.
As will now be apparent, the present invention can
be utilized in making various types of glued laminated wood,
l~ including laminated wood having parallel laminated veneers
as well as cross~banded structure, depending upon the orien-
tation of the wood grains of the component veneers and the
selected combination of undersized veneers used in making
the component unit veneer sheets. Since each t~pe of la-
minated wood has its own applications, it will be apparant
that each of the previously described embodiments has a
particular use.
It would be preferable that the veneer sheets be
used in the making of glued laminated wood according to the
in~ention have a thickness in the range of from l to 4 mmO
Since the stepped deforma~ion of each veneer sheet which
occurs during the process makes use of its inherent flexi-
bility, the greater the thickness of the veneer sheets, the
mcre difficult it will be to successfully make the product.
With this and the above range of preferred thicknesses of
veneer sheets taken into consideration, the practical
range of thicknesses of the resulting product will be from
about 6 to 50 mm. Depending upon the veneer thickness and
i~3 `
}~.r~ ~,
;8~
- 29
other factors, the present invention will exhibit a re
markable advantaye in terms of economy when the component
~nit veneer sheets have dimensions of frorn 100 to 1,000 mm
in the L direction. As to the number of plies in the la-
S minated wood, any desired number can be selected, prefe-
rable from within the range of from 3 to 12 plies according
to various factors including the desired thickness of pro-
duct to be made, the veneer thickness to be used, the
particular wood species of which the venee~ is made, and
lQ so on.
The method of manufacturing glued laminated wood,
including plywood, according to the present invention will
now be explained with reference to Figs. 26 to 31:
Fig. 26 shows a schematic diagram illustrating the
basic procedural steps for manufacturing the continuously
produced product, which include a gluing (adhesive applying~
process or station designated generally by reference letter
A, followed se~uentially by a laying-up process or station
B, a tacking station C, a cutting station D, and a final
bonding station E.
In the gluing station A, a series of unit veneer
sheets 2 each having the same length L and thickness are
arranged with their respective leading ends lapped on the
trailing ends of the preceding veneer sheets as shown in
the drawing. In such arrangement, they are conveyed face-
up by conveyor 28 in the direction of the arrow succesive-
ly beneath a glue spreader 38, which coats the upper surfa-
ces of the veneer sheets 2 with a continuous film of glue
t .,Y ~.
. ~ `
~z~
- 30 -
which covers only the exposed surfaces thereof, the glue
being indicated by the dots GL in the drawing. 'rhe coat-
ing of glue may be accomplished by use of any suitable
glue applying apparatus such as the glue spreader 38
shown schematically in Fig. 26, a curtain coater, a film-
glue applying device which is disclosed in the Canadian
Patent Application No. 418,699 filed on December 29, 1982
by Meinan Machinery Worlcs, or any other conventional means.
Anyway, the gluing process A is performed in such a way
that no glue is applied to the opposite underside surface
of each veneer sheet 2, or on the lapped upwardly facing
portion at the trailing end of the veneer sheet. The
length of overlap of each veneer sheet on the other is
nominally equal to the quotient determined by dividing the
unit veneer length L by the number N of plies to be in the
laminated wood structure, i.e~ the same length as the length
Q of offset of the veneer sheets in the laying up operation
which follows.
~s thus coated with glue, the unit veneer sheets 2
are transferred to the subsequent laying-up station B, by
sequentially dropping the sheets 2, as indicated by arrows F,
from the con~eyor 28. On the laying-up conveyor 28a,
each veneer sheet 2 is lapped only on the glued portion of
its proceeding sheet, thereby exposing only the unglued
2~ portions of the veneer sheets. That is, in the laying-up
station B each veneer sheet 2, which in the illustrated
laying-up station has reversed its direction of movement
from that of the ~luing conve~or 28, is laid on the preceding
~9
/~i
~;
~2~
- 31 -
veneer with its now unglued leading end exposed as a re-
sult o~ the continuous or index;ny movement of the prece-
ding veneer shee~. It will there~ore be apparent that
the }apped length portion, or g~ue coated portion, on
each veneer sheet is substantially equal to ~
As thus laid-up in a continuous, sequentially over-
lapped length, the series o~ veneer sheets 2 are conveyed
on conveyor 28a to the tacking station C, which includes
a cold press (not shown) or any other convenient device,
such as a stapler, a hot-melt glue applicator, etc., de-
signed to temporarily hold the individual laid-up veneer
sheets 2 together in a laminated form while malntaining
the correct relative positions thereo~.
The continuous lamination of veneers thus formed
is transferred to the subsequent cutting station D, where
it is cut into the desired panel lengths. The panels are
then moved to the bonding station E which includes a device,
such as a hot press, designed to cure the layers of glue
between the veneer sheets while pressing them to permanently
set them in their desired deformed shapes having the
tandemly arranged and displaced straight length portions
lb and curved length protions lc (Fig. 1). As will be
noted from Fig. 1, during the bonding operation at the
station E, each straight length portion lb is displaced,
in the direction o~ the thickness T of the product, by a
distance substantially e~ual to the thickness t o~ its
adjacent veneer sheet. Of course, if the product is made
of veneers having verying thicknesses, the extents to which
. ..~
~2~
- 32 -
its s-traight length portions are displaced will be corres-
pondingly varied. E'or example, in a typical hot press
operation, pressure on the order of about 7 to 21 kg/cm2
~or about 3,000 to 9,000 lbs/ft2) is applie~ at a tempe-
rature oE about 120 to 176C to cure the glue between the
veneers and permanently set and bond them together.
In the described method of manufacturing glued la-
minated wood, it is desirable during the gluing process A
that glue should be applied to each veneer sheet 2 leaving
an appropriate unglued portion to allow very little of the
glue to be exposed when it is laid-up on the preceding ve-
neer sheet in the subsequent la~ing-up process B. For
example, in an arrangement of veneer sheets 2 in the la~ving-
up process B wherein each pair of adjacentl~ opposite ends
2a, 2_ of two overlapped veneer sheets 2 have their ends
in vertical alignment with each other as exemplified by
~ull lines in the fragmenting side elevational showing of
Fig. 27, each veneer sheet 2 will have an exposed portion
of its surface on either face ~1hich is exactly e~ual to the
distance of L/N twherein ~ represents the longitudinal di-
mension of each unit veneer sheet 2; and N the number of
veneer plies in ~he laminated wood to be made). As sta-ted
earlier, in connection with the description of the product
itself, the above-said distance, and therefore the surface
area to be exposed, varies depending upon the shapes of
the veneer ends, the sizes thereof, the relative positions
of each pair of the adjacently opposite ends 2a~2b, etc.
For example, when the edges of each pair of corresponding
j:" .:'
8~
- 33 -
veneer .sheet ends 2a and 2b are arranged or laid up in
oth~r ways s~ch that one end overlaps the other a distance
S, or such that the ends 2a, 2b are not in transverse
alignment, but are spaced apart Erom each other in the
longitudinal direction a distance S', as indicated by
phantom lines in Fig. 27 respectivel~, the unglued area
to be exposed should be decreased in the case of the over-
lapping relation S, and increased when they are to be
~paced apart as shown by S', respectively. In either event,
it i.s desirable that each v~neer sheet 2 have glue applied
a~ station A in a way such as to maintain the appropriate
~nglued areas which will be exposed at the laying-up
station B ~Fig. 26).
Although maintenance of such unglued portion on
each veneer sheet 2 may be accomplished by properly contro'-ling
the glue applying device 38, it is more convenient to apply
glue in a continuous manner to the series of veneer sheets
2 which are successively lapped at -their ends using the
appropriate lapping distance, thus permitting the use of
any known type of glue applying device~ The length over
w.h.ich. the respective ends of adjacent veneer sheets 2 are
lapped on the gluing conve~or 28 ~Fig. 26) and as will pro-
vide the unglued areas is determinea by the lengthwise
dimension o~ the surface area to be exposed in ~he laying~
up process B (Fig. 26), which is the length interval Q
at which the veneers are laminated in offset relation to
2S each other. When the paired ends 2a, 2b of the upper and
lower veneer sheets 2 in the laying-up process B are
. . . ~
~2~
~ 34 -
themselves to be longitudinally overlapped as indicaked
by S, or are going to be longitudinally spaced apart
from each other as at S' in Fig.~27, the lengths over
which the ends of any two adjacen-t veneer sheets 2 are
lapped in the gluing process A will be decreased or in-
creased, accordingly, as indicated by phantom lines in
Fig. 28. Regarding the value of S or S' r depending upon
the usago of the glued laminated wood each is preferably
within the range of less than 50 times or, more preferably,
less than 5 times, the thickness of the unit veneer sheet
2 to be employed in making the product. Though it is
ideal that the area of unglued surface obtained in the
gluing process A and the area o~ sur~ace -to be exposed in
the subse~uent laying-up process B should exactly coin-
cide, errors are unavoidable in actual practice during
both the gluing and the laying-up processes A and B. To
compensate for such errors, any practical adjustment may
be made, as by increasing or decreasing the areas of the
unglued surfaces in the gluing station, etc.
Figs. 29 and 30 respectively illustrate two types
of flight conveyors which may be used to transport the
veneer sheets 2 while retaining the correct overlapping
relation between them during either the gluing process A
or the laying-up process B (Fig. 26). The conveyor 28
shown in Fig. 29 includes several conveyor belts (onl~
one of which is shown in the drawing) having veneer sheet
locating steps 29, for receiving the trailing ends of the
veneer sheets~ The conve~or 30 in Fig. 30 includes several
. .y ~,
~2~
-35 -
conveyor belts ~only one of which is shown in -the drawing)
having veneer sheet locating pins 31 projec-ting therefrom,
for the same purpose. By placing each veneer sheet 2 onto
the conveyors whether in automatic, se~ automatic or manual
manner, it will be transported while being located and
overlapped correctly in the longitudinal direction. Thus,
a high standaxd of accuracy and stability in veneer posi-
tioning can be achieved during the transporting of the
veneer sheets through either the gluing or the laying-up
processes.
~eferring now to Fig. 31, to permit the gluing and
laying-up processes to be carried out in close conjunction
with each other in order to synchronize the relative posi-
tioning of the veneer sheets in the two processes, a com-
mon drive 32 is provided for directly driving the conveyor
28 for the gliuing station A and for driving the conveyor
28a for the la~ing-up station B via any suitable speed-
reducing davice 33, as shown schematically in Fig. 31. By
such drive arrangement, the two different processes A and
2~ _ can be operatively synchronized so that error, if any,
between the rates of travel of the veneer sheets during
the two processes will take place at a given; and therefore,
predictable value. Therefore, adjustment for compensating
ths error may be made with ease.
2S If the drive 32 operates in a continuous manner, a cold
press of a continuous type may be used in the tacking station
C. If the drive 32 is capable of automatically interrupted
operation, it is possible to employ a cold press having
:~`f i
~2~
,
- 36 -
intermittent operation for the tacking process C.
When it is permissible for the glue coating on the
veneer sheets 2 to be e~posed in the subsecluent layiny-up
process B, or when it is intended to have such exposure
of glue on the product, the gluing process A may be con-
ducted without maintaining the above-mentioned specific
unglued areas on the veneer surfaces. For example, the
veneer sheets 2 may be merely passed through the glue
spreader 38 ~Fig. 26) one after another in end-to-end rela-
tionship, without lapping their ends as shown in Fig. 28,
so as to coat the glue on the entire surface of each veneer
sheet. By so doing, a continuous length of glue exposure
will appear on the face or faces of the continuously laid-
up veneer sheets 2 formed in the laying-up station B.
Such exposure of glue on the laid-up veneers is permissible
or even desired, depending upon -the type of laminated wood
panel to be produced. For example, the glue which is ex-
posed on the face can facilitate the application of an
additional layer of overlay of a flat sheet o~ veneer,
printed paper, hoard or any other suitable overlay material
_ which would be laminated onto the face or faces of the
product, as illustrated in ~ig~ 32. The overlay sheet O
may be added during or after the laying-up process, as
desired.
Thus, it is to be understood that the particular
embodiment o~ the method of manufacturing glued laminated
wood according to the invention, specifically with refe-
rence ~o the gluing process A, will vary depending upon
,. ,
.,~.
,,, ..i
., .~
- 37 -
its in-tended relationship with the subsequenk layiny-up
process B. Thus, -the gluiny method may be conducted in
a variety of ways other than those described above.
With reyards to the manner in which the gluiny and
laying-up stations A and B are disposed relative to each
other for transferring the veneer sheets from the former
to the latter, they may be located on the same level by
arranying the gluing station A on the upstream side and
the laying-up station B on the downstream side with refe-
rence to the direction of transfer of the veneer sheets
2, although th~y are located on different levels in the
embodiment of Fig. 26. Furthermore, these two processes
A and B may be arranged in line with each other, wherein
the conveyor 28a is moved in the same direction as the
conveyor 28, without being reversed as in the illustrated
embodiment of Fig. 26, and instead each veneer sheet 2
coated with glue in the gluing station A is turned by
reversing the leading and trailing ends thereof before
it i5 transferred to the subsequent laying-up station B
to be lapped on the glued portion of its preceding sheet.
Therefore, th0se two stations may be opera-tively connected
in any manner according to any specific r~quirements.
Furthermore~ in the method of laminated wood manu
facturing shown in Fig. 26, the tacking process C may be
either replaced by, or immediately followd by the bonding
process E by substituting or adding a hot press of a type
designed to operate in a continuous or intermittent manner,
whereupon the laying-up process B and the final bonding
' i
~2~
- 38 -
process E can be integrated into a wholly continuous
process. In such an arrangement, the continuously produced
glued laminated wood can be cut into any desired leny-ths
in the cutting process D which would then ~ollow the bonding
process E. Thus, any desired lengths of plywood panels
can be produced from a continuously produced run of glued
laminated wood.
The present invention contemplates glued laminated wood
having a novel laminated structure of veneers, which makes
possible the formation of laminated wood of any desired
length from veneer sheets wh-ich are too short or too narrow
for such desired length of the product, thus permitting
economical usage of veneer.
Regarding other general considerations associated with
veneer or laminated wood making such as the kind of wood to
be used, thickness, size, how to deal with lathe checks
on the veneer surfaces, number of plies, adhesives to be
used, moisture content in veneers, etc., none are affected
in any way by the practice of the present invention, but
~o are subject to ordinary practices in glued laminated wood
making.
~ hile the invention has been illustrated and described
with reference to various specific embodiments, it is to be
understood that various modifications in the details of the
glued laminated wood construction or its method of manufac-
ture may be made withou-t departing from the spirit and scope
of the invention.
, . ~
