Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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BACEGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an apparatus for
regulating a leading end stacked position in a stacker
for successively stacking thin sheet materials.
2. Description of the Related Art
Conventionally, as an example of stackers for suc-
cessively stacking sheet-like articles one upon another,
the one of a type in which sheet-like articles are suc-
cessively introduced by means of various kinds of convey-
ers such as a stab conveyer,.a suction conveyer and the
like, into a stacker body, and then, they are forcibly or
freely dropped obliquely and stacked one upon another,
allowing the sheet-like articles to directly abut, at
their leading ends, against a stationary ruler located at
a predetermined leading end stacking position, so as to
regulate the leading end stacked positions of the stacked
sheet-like articles at a substantially uniform position
has been well-known and it has an e~tremely simple struc-
ture, having a reasonable degree of stacking efficiency.
However, a sheet-like material can directly abut the
stationary ruler, provided that stiff plate-like articles
such as plywood or synthetic resin plates are introduced
at low speeds into a stacker. Should plate-like articles
or the like which are even stiff more or less be intro-
duced into the stacker at high speeds, or should weak
sheet materials as the plate-like articles be introduced
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into the stacker (the conveyance of veneers in a direc-
tion perpendicular to the fiber thereof can be e~empli-
fied), a fatal problem such as damage to the leading end
of a plate-like article or buckling of the intermediate
part thereof would be likely to occur. Accordingly, it
is difficult to stack the weak plate-like articles one
upon another with the use of the above-mentioned system.
Further, there is snother well-known system in which
a movable ruler that is held by a resilient member such
as a spring so as to be resiliently displaceable, instead
of the stationary ruler in the above-mentioned system, in
order to buffer and absorb a shock caused by impingement
of a plate-like article upon the movable ruler through
e~tension and retraction of the spring, and after the
plate-like article is once dropped to a position down-
stream of a predetermined stacking position, the plate-
like article is moved again in a direction reverse to the
direction of introduction of the plate-like article by
the resilient force of the above-mentioned resilient
member so as to regulate the leading end stacked posi-
tions of plate-like articles which are therefore main-
tained so as to be substantially uniform. This improved
system is excellent in high speed responsiveness, and
reduces the possibility of occurrence of a fatal problem
caused by an inclination of the posture of a plate-like
article upon conveyance, so as to be relatively effective
in comparison with the aforementioned embodiment.
CA 0213S260 1998-03-23
However, in order to move again the once dropped
plate-like article in a direction reverse to the direc-
tion of introduction of the article as mentioned above,
it is required to enable the plate-like articles to
smoothly slide one upon another. E~owever, if the plate-
like article6 are weak thin sheet materials, no suffi-
cient force ~can be transmitted satisfactorily from the
front end to the rear end thereof 80 as to induce a
problem such that the front end part or the intermediate
part of a thin sheet material to be again moved is buck-
led. Thus, even with the improved system, it i8 diffi-
cult to stack the sheet materials one upon another. AB a
resul~, either the conveyance of the sheet materials has
to be once stopped each time when a sheet material is
vertically dropped for stacking by neglecting a decrease
in the stacking efficiency, or they are randomly stacked
without regulating the positions thereof. However, it
ha~ been practically unreasonable either.
SUMMARY OF THE INVENTION
The present invention has been accomplished to
improve the above-mentioned conventional apparatus so as
to efficiently stack thin sheet materials one upon anoth-
er, even though they are more or less weak, while the
leading end stacked positions of the thin sheet materials
CA 0213~260 1998-03-23
are maintained to be substantially aligned.
According to the present invention, there is provided
an apparatus for regulating downstream end stacked positions of
thin sheet materials which are introduced into a thin sheet
material stacker at high speeds, and are dropped and stacked
one upon another, comprising:
- a retractable damping ruler normally standing by on
a path of dropping of the downstream end of the thin sheet
material, and adapted to abut said downstream end and then
retracted;
- a stationary ruler located on a path of dropping in
abutment against said damping ruler; and
- a restoring mechanism for returning said damping
ruler to said stand-by position each time when the thin sheet
material is dropped below said damping ruler.
According to the present invention, there is aslo
provided an apparatus according to the present invention for
regulating leading
4a
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end stacked positions of thin sheet materials which are
introduced into a thin sheet material stacker at high
speeds, and are dropped and stacked one upon another,
comprises: a retractable damping ruler normally standing
by at a stand-by position upstream of a predetermined
leading end stacking position, and adapted to preferen-
tially abut the leading end of a thin sheet material each
time when the thin sheet material introduced into the
stacker is obliquely dropped and then retracted; a sta-
tionary ruler always located at the predetermined leading
end stacking position, and adapted to finally abut the
leading end of the thin sheet material, in place of the
damping ruler which is retracted in association with
abutting thereof against the thin sheet material; and a
restoring mechanism for returning the damping ruler to
the stand-by position each time when the sheet material
is dropped below the damping ruler.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will be more apparent from the
ensuring description with reference to the accompanying
drawing wherein:
Fig. 1 is an explanatory schematic plan view illus-
trating a stacker with a regulating apparatus according
to the present invention;
Fig. 2 is an e~planatory schematic side view illus-
trating the stacker shown in Fig. 1;
Fig. 3 is an explanatory enlarged perspective view
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illustrating a part of the stacker e~emplified in Figs. 1
and 2;
Fig. 4 is a partially enlarged explanatory cross-
sectional view taken along the line A-A of Fig. 1;
Fig. 5 is an enlarged explanatory plan view of
rulers and a thin sheet material when the thin sheet
material is located at the position shown in Fig. 2 with
a dotted line; and
Fig. 6 is an explanatory view from the upstream side
illustrating essential portions when the thin sheet mate-
rial is located at the positipn shown in Fig. 2 with a
dotted~line.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENT
A leading end stacked position regulating apparatus
in thin sheet material stacker according to an embodiment
of the present invention will be explained in detail with
reference to drawings. It is noted that a control system
for controlling the operation of equipments constituting
a stacker has no special configuration but a completely
usual configuration, and accordingly, the control system
is not shown in the drawings for the sake of convenience.
Fig. 1 is an e~planatory schematic plan view of a
stacker for veneers according to the present invention;
Fig. 2 an explanatory schematic side view of the stacker
shown in Fig. 1; Fig. 3 an explanatory enlarged perspec-
tive view of a part of the stacker shown in Figs. 1 and
2 1
2; Fig. 4 a partially enlarged explanatory cross-
sectional view taken along the line A-A of Fig. l; Fig. 5
an enlarged explanatory plan view of rulers and a veneer
when the veneer is located at the position shown in Fig.
2 with a dotted line; and Fig. 6 an explanatory view from
the upstream side illustrating essential portions when
the veneer is located at the position shown in Fig. 2
with a dotted line.
In the figures, reference numeral 1 denotes a stab
conveyor which conveys a rectangular veneer P in a direc-
tion perpendicular to a fiber direction thereof and which
comprises stab belts la located near both lateral sides
of the veneer P and mounted with a number of nails lf,
stab belts lb located near the centerline portion of the
veneer P and mounted with a number of nails lf, pulleys
lc, driving shafts ld, belts guides le to maintain the
belts la at a fixed position even when the belts la are
subjected to a force and others. The stab conveyor 1 is
driven in the arrow-marked direction at high speeds by a
drive source (not shown) such as a motor or the like, and
conveys continuously the veneer P which is stabbed from
above with the nails lf at the stabbing position upstream
of the stacking position to a predetermined station where
the stabbed veneer P is released.
Reference numeral 2 denotes a strike-release mecha-
nism to hit and drop the veneer P obliquely downward
which comprises strike-release levers 2a corresponding to
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the stab belts la located near both lateral sides of the
veneer P, strike-release levers 2b corresponding to the
stab belts lb located near the centreline portion of the
veneer P, connecting arms 2c, pivoting arms 2d, driving
shafts 2e and the like. Based on a start signal from a
sheet material detector (not shown) which detects that-
the veneer ~ has reached the predetermined station by
means of the stab conveyor 1 or from an encoder (not
shown) which measures a distance of transfer from the
stab position, the strike-release mechanism 2 is inter-
mittently driven by a drive source (not shown) such as a
servo motor, a motor with a clutch and a brake and the
like, and forcibly releases and drops the sheet material
P obliquely downward when the veneer P reaches the prede-
termined station.
As clearly illustrated in Figs. 2 and 6, in the
strike-release mechanism 2, the bottom position of lower-
ing of strike-release levers 2a corresponding to the stab
belts la located near both lateral sides of the veneer P
is set lower than the bottom position of lowering of
strike-release levers 2b corresponding to the stab belts
lb located near the centerline portion of the veneer P
by differentiating lengths of relevant connecting arms
2c.
~ eference numeral 3 is a damping ruler having ruler
plates 3a, supporting plates 3b, a slide beam 3c, slide
guides 3d and the like, and is mounted on slide surfaces
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5a of slide bases 5 in a slidable manner as describe
below. Normally, the damping ruler 3 is standing by at
the ~tand-by position M on a path of dropping of the down-
stream end of the sheet material P. The stand-by posi-
tion M is located upstream of the predetermined down-
stream end stacking position N as illustrated with a
solid line. The damping ruler 3 retracts to the down-
stream side as illustrated with a two-dot chain line when
abutting the veneer P moving obliquely downward, and is
returned again to the stand-by position M through a
restoring mechanism, as described below, each time the
veneer P drops below the damping ruler 3.
Reference numeral 4 denotes a stationary ruler
having regulating plates 4a, a stationary beam 4b fixed
to the frame (not shown) of the stacker and other mem-
bers. The regulating plates 4a are fi~ed to the station-
ary beam 4b in such a manner as to be positioned on the
path of dropping of the downstream end of the veneer P
which abuts the ruler plates 3a and moves obliquely
downward, thereby being always located at the predeter-
mined end stacking position N.
Reference numeral 5 denotes a slide guide also
serving as stopper having a slide surface 5a, a guide
wall 5b, a stop wall 5c and others, and is fi~ed to the
frame (not shown) of the stacker or the like so that the
slide surface 5a maintains levelness or substantial
levelness. The slide guides also serving as stoppers 5
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support the damping ruler 3 in a slidable manner and
regulate a return thereof to the stand-by position M uni-
formly.
Reference numeral 6 denotes a restoring mechanism
comprising an air cylinder and others. The restoring
mechanism returns the damping ruler 3 to the stand-by
position M based on a delay signal or the like which
delays quantitatively with respect to the start signal
from the strike-release mechanism 2 each time the veneer
P drops below the damping ruler 3.
Reference numeral 7 denotes an elevatable stacking
bed, which receives the veneers P dropping one after
another always at a substantially stationary level under
control of a controller (not shown) or the like based on
a start signal from a level detector (not shown) which
detects the level of the top surface of the stacking bed
7 (top surface of a bottom plate when used as needed)
when stacking starts and which detects the level of the
top surface of a stack Pa of veneers stacked on the
stacking bed 7 after stacking is started.
Reference numeral 8 denotes a stationary guide
having guide plates 8a, stationary beam 8b and the like.
Exceptionally, when a preceding veneer P is caught
obliquely by the stationary ruler 4 and stacked in the
caught state, a succeeding veneer P to be stacked abuts
the preceding veneer P, not the stationary ruler 4, and
is sprung to the upstream side by elasticity of the
13S2B~3
preceding veneer P. In such a case, the stationary guide
8 abuts the upstream end of the succeeding veneer P,
thereby preventing the veneers P from deviating greatly.
The stationary guide 8 is fi~ed to frames (not shown) of
the stacker or the like so as to be opposed to the sta-
tionary ruler 4 with a sufficient distance take therebe-
tween in comparison with the length of~the veneer P in
the direction of conveyance.
Also, as clearly illustrated in Fig. 5, the center
part of the damping ruler 3 slightly projects in a direc-
tion reverse to the direction that the veneer P is con-
veyed. ~~
The stacker according to the present invention isconstructed, for e~ample, as described above, and the
veneer P which is stabbed by nails lf of the stab convey-
or 1 and conveyed to the predetermined station is forci-
bly hit and dropped by the strike-release mechanism 2.
Since the veneer P has kinetic energy ~inertia), it drops
obliquely downward as indicated by P' with a two-dot
chain line from the position illustrated with a solid
line in Fig. 2.
In this case, as shown in Fig. 6 (the veneer P'
is illustrated with a solid line in Fig. 6) which is a
view from the upstream side of primary portions of the
apparatus when a sheet material is at the position indi-
cated by P' with a two-dot chain line in Fig. 2, the
veneer P' drops as being kept in abutment against the
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strike-release levers 2a and 2b applied from above, and
also drops in an upwardly conve~ly curved state because
the strike-release levers 2a are different from the
strike-release levers 2b in the bottom position of lower-
ing as described above. AB a result, the geometrical
moment of inertia of the veneer P increases, leading to
the state that a strength has improved substantially in
the fiber direction and the direction perpendicular
thereto; accordingly, the downstream end of the veneer P
abuts the ruler plates 3a of the damping ruler 3 standing
by at the stand-by position M AS a result, this abut-
ment suppresses the occurrence of such phenomena as a
damage to the end portion of the veneer P or the buckling
of the central portion thereof; accordingly, increasing
the speed of conveyance raises no problem with a result-
ant stacking process at a better efficiency.
On the other hand, when the veneer P abuts the ruler
plate 3a, the damping ruler 3 retracts as illustrated
with a two-dot chain line, while the veneer P e~erts a
part of kinetic energy owned thereby to the damping ruler
3 and drops further obliquely downward in a decelerated
state. Then, the veneer P stalls due to abutment against
the regulating plate 4a of the stationary ruler 4 of the
veneer P and is stacked on the stacking bed 7 or a
stack Pa of thin plates with its end stacking position
being regulated. Also, each time the veneer P drops
below the damping ruler 3, the restoring mechanism 6
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returns the damping ruler 3 to the stand-by position M
(at least by the time when the next veneer P is hit and
dropped).
Similar operations are repeated to stack veneers
one after another. In the construction of the regulating
apparatus according to the present invention, a veneer
exerts a part of kinetic energy owned thereby to the
damping ruler which the plate first abuts against, and
then abuts the stationary ruler in a decelerated state.
Therefore, even when the veneer is somewhat weak, a fatal
phenomenon is less likely to occur as compared with the
conventional case where the veneer abuts the stationary
ruler from the beginning. Accordingly, the veneerm can
be introduced at a fairly high speed from the beginning
with a resultant eff'icient stacking work.
As clearly illustrated in Fig. 5, the center part of
the damping ruler 3 is slightly projected to the upstream
side in the direction of conveyance of the veneer P.
Therefore, even when the veneer P is somewhat inclined
with respect to the direction of its conveyance as illus-
trated with a dotted line, a substantially wide portion
of the leading end thereof (a portion corresponding to
two right-hand ruler plates 3a in this embodiment) which
ranges from the right hand lateral side end to the cen-
terline portion abuts the damping ruler. As a result, a
force imposed on the veneer P at the abutment time is
distributed as compared with the case where the ruler
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plates 3a are arranged on a straight line perpendicular
to the direction of conveyance of the veneer P, and
therefore there arises no problem of damage to the veneer
P or the like. Moreover, since the veneer P finally
abuts the stationary ruler and an incline thereof i8
corrected, the posture of stacking does not deteriorate.
Needless to say, if the veneer P is not inclined with
respect to the direction of its conveyance as illustrated
with a solid line, a substantially wide portion near the
centerline portion thereof abuts the ruler plates 3a in a
substantially-uniform manner to distribute a force im-
posed on the veneer P; therefore~ it is possible to carry ~~
out stacking effectively without any problem.
Further, in the stacker according to the embodiment,
since the veneer P is put in an upwardly convexly curved
state by the strike-release mechanism 2, the veneer are
curved in a fairly remarked manner as needed. However,
an excess curve is apt to interfere with the stable
settlement of the veneer (at the stacking position) and
therefore should be avoided. It is desirable that a
preferable degree of curvature be selected based on
experiments.
In the aforementioned embodiment, the damping ruler
3 in a single row in the direction of conveyance of the
veneer P is used. However, a damping ruler in a multi-
row form may be used wherein the damping ruler is divided
into a plurality of sub damping rulers in the direction,
~ 1 3-5=2~
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which sub damping rulers are normally spaced adequately
for damping and located at respective stand-by positions.
In addition to the form of the aforementioned embodiment
wherein the kinetic energy exerted from the veneer P is
positively dissipated by a friction force acting on the
slide guides 3d through the slide surfaces, it may be -
possible to employ the form wherein the slide guides 3d
are supported in an easily slidable manner through di-
rect-acting bearings or the like for retracting the slide
guides 3d substantially frictionlessly at least immedi-
ately after abutting the end of a thin plate material.
In a word, it is efficient if the damping ruler preferen-
tially abuts against the end of a thin plate material and
retracts to change places with the stationary ruler.
Design may be modified as appropriate without sticking to
the form of the aforementioned embodiment. In any case,
if the dead weight of the damping ruler 3 is too heavy or
too light, a smooth damping operation cannot be e~pected;
therefore, it is desirable to select the weight based on
full-sized e~periments. When the dead weight of a sheet
material changes periodically, it is desirable to employ
adjusting means for making adjustment by adding a weight
to or removing from the damping ruler 3.
As for the form of the stationary ruler, it is
sufficient if the stationary ruler changes places with
the damping ruler to abut the end of a thin plate materi-
al and thereby regulating the end stacking position of
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the thin plate material. Design may be modified as
appropriate without sticking to the form of the aforemen-
tioned embodiment. However, it is also desirable to
select the spacing between the end stacking position
where the stationary ruler is located and the stand-by
position where the damping ruler is standing by baséd on
experiments. --
Moreover, the form of the stacker body is not to belimited to the form of the aforementioned embodiment. In
a word, various known forms may be applicable if thin
plate materials introduced to a predetermined station by
means of various conveyors or the like are dropped
obliquely downward and stacked.
In the above embodiment, the turning path type
strike-release mechanism is used, and the length of the
connecting arm 2c is differentiated at appropriate posi-
tions, thereby differentiating the bottom position of
lowering of a strike-release lever at desired positions.
However, even in the case where a strike-release mecha-
nism of the same kind is used, for example, by changing
the in~tallation level of the driving shaft 2e at appro- ~
priate positions, it is possible to differentiate the
bottom position of lowering of a strike-release lever as
in the above embodiment even when all connecting arms are
made identical in length. Also, it is possible to carry
out similar setting by using a strike-release mechanism
of other type such as a vertical path type. What is
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213~2GO
essential is that the bottom position of lowering of
strike-release levers corresponding to stab belts located
near both lateral sides of a sheet material is set lower
than the bottom position of lowering of strike-release
levers corresponding to stab belts located near the
centerline portion of the sheet material. There aFe no
special restrictions on the type of the strike-release
mechanism itself.
With the arrangement stated above in which a thin
sheet material exerts a part of energy owned thereby to
the damping ruler against which it abuts so that it
impinges upon the stationary~ruler in a decelerated ~~
condition, the above-mentioned fatal problem can hardly
occur even though it is more or less, weak, and accord-
ingly, thin sheet materials can be introduced at rela-
e tively high speeds with no hindrance, thereby it is
possible to perform efficient stacking thereof.
Further, even though a thin sheet material is
slightly inclined in the direction of conveyance, at
least a part of one side of the section of the thin sheet
material extending from the leading end to the middle
thereof makes contact with the damping ruler in a sub- -
stantially uniform condition, and accordingly, the load
is dispersed so that the possibility of occurrence of the
fatal problem due to the concentration of load to a
narrow part thereof, caused in the conventional appara-
tus, can be reduced, and further, the inclination of a
21352~0
thin sheet material can be compensated for, there is no
risk of deterioration of the stacked postures of sheet
materials. Needless to say, a sheet material which is
not uniformly inclined in the direction of conveyance, a
part of the middle section thereof solely abuts the
damping ruler in a substantially uniform condition~so
that the load is dispersed, thereby it is also possible
to effectively stack thin sheet materials one upon anoth-
er without hindrance.
As clearly understood from the above, with the use
of the regulating apparatus according to the present
invention, sheet materials which are even more or less
weak can be efficiently stacked one upon another while
the leading end stacked positions thereof can be regulat-
ed in a substantialIy uniform condition, and the leading
end stacked positions can be reasonably and smoothly
regulated even though the leading end of a sheet material
is slightly inclined in the direction of conveyance, and
accordingly, the applicability to the existing process is
excellent, and technical effects and advantages in the
application to a process of stacking sheet materials can
be remarkable.
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