Note: Descriptions are shown in the official language in which they were submitted.
CA 02247236 1998-09-11
VENEER REELING APPARATUS
1 FIELD OF THE INVENTION
The present invention relates to an apparatus for winding or
reeling a sheet of wood veneer into a roll while the sheet is being
transferred to the apparatus with its fiber orientation directed
perpendicularly to the direction in which the sheet is transferred.
BACKGROUND OF THE INVENTION
For understanding of underlying problems of the invention,
firstly reference is made to FIG. 28 schematically showing a
conventional veneer reeling apparatus which is disclosed by
Publication of Unexamined Japanese Patent Application (Kokai)
57-53306 of 1982.
This apparatus has a plurality of endless belts 141 for
conveying veneer sheet 140, each trained round a driven front
pulley 145 disposed swingable as indicated by double-headed arrow
about a pivotal axis defined by a rear pulley (not shown) located
on opposite side of the belts 141. The reeling apparatus further
includes a take-up reel 143 extending above the upper legs of the
belts 141 for winding thereround veneer sheet 140 into a roll 144
and a plurality of sectional touch rolls 142 mounted on a shaft
provided just below the reel 143. Each sectional touch roll 142 is
located between any two adjacent belts 141 and driven to rotate at
a peripheral speed that is slightly higher than the traveling speed
of the conveyer belts 141. The shaft carrying the touch rolls 142
is resiliently.supported, as indicated by double-headed arrow, and
urged so as to make the touch rolls 142 to be in pressing contact
with veneer roll 144.
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1 In the above apparatus, veneer reeling is accomplished by
rotating the veneer roll 144 by frictional force from the touch
rolls 142 pressed thereagainst with a force that is large enough to
effect the rotation. Because the veneer roll 144 and the touch
rolls 142 are engaged substantially in circle-to-circle contact and
hence the length of contact therebetween as seen in veneer
conveying direction is rather short, the magnitude of stress
resulting from the contact and acting on a unit area between the
touch roll 142 and the veneer roll 144 is disadvantageously large.
Consequently, the veneer sheet 140 is subjected at the point of
contact to a stress that tends to strain or deform the sheet.
On the other hand, a veneer sheet 140 as peeled by a veneer
lathe (not shown) comes out therefrom inherently in such a form
that the sheet is waved at short intervals. Further, veneer sheet
140 is formed in the lower surface thereof with a number of small
cracks, usually called "lathe checks", produced during peeling
operation. Thus, veneer sheet generally tends to be deformed
easily when it receives an external force and, because a wood
veneer sheet is of heterogeneous quality, such deformation takes
place variably from one location thereof to another along the line
of contact between the veneer sheet and the touch rolls 142 even
when it is subjected to application of the same force.
When subjected to the above straining or deforming stress at
the touch rolls 142, however, veneer sheet 140 is stretched or
extended in the region upstream of the touch rolls 142. Because
this extension takes place variably from one location to another of
the veneer sheet 140 across the direction in which it is moved,
sheet movement tends to be deviated from a straightforward course
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along the belts 141, with the result that veneer sheet 140
may collide against a frame of the reeling apparatus, thus
causing a damage to veneer sheet. Furthermore, any
excessive extension of veneer sheet 140 causes slack in the
sheet as indicated by 140a, which may result in formation of
folds. If such folds in the veneer sheet 140 are wound
round the roll 144, the sheet is broken at bends of the
folds, thereby affecting the veneer quality and yield.
SUMMARY OF THE INVENTION
Therefore, it is an object of the invention to
provide a veneer reeling apparatus which makes possible
smooth reeling operation without allowing veneer sheet to be
folded or deviated from its intended course along conveyer
belts so that damage to veneer sheet and reduction in veneer
yield as described above are prevented.
According to the present invention, there is
provided a veneer reeling apparatus for winding a veneer
sheet into a veneer roll, comprising: a freely rotatable
take-up reel for winding the veneer sheet into the veneer
roll; a plurality of spaced conveyor belts extending below
said take-up reel, perpendicular to the axis of the take-up
reel, the conveyor belts for being driven to move in a
direction to advance a veneer sheet placed on said belts
toward said take-up reel; means for moving said take-up reel
toward and away from said belts; first urging means for
urging each of said belts toward said take-up reel to keep
the belts in resiliently pressing contact with the veneer
roll, to fractionally drive the veneer roll; detecting means
for detecting an increment in diameter of the veneer roll
during reeling; said detecting means including a roll member
disposed below said take-up reel and said belts and
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extending parallel to said take-up reel, second urging means
for urging said roll member in resiliently pressing contact
with the veneer roll, said roll member being movable away
from said reel as the veneer roll increases the diameter of
the veneer roll during reeling operation, and force
detecting means responsive to the movement of said roll
member for detecting the force with which said roll member
presses against the veneer roll, said force detecting means
being operable to generate a signal upon detection of a
predetermined magnitude of force in response to an increase
in diameter of the veneer roll; and a control operable in
response to the signal from said force detecting means to
generate a command signal to activate said take-up reel
moving means to move said take-up reel away from said belts
to compensate for the increment.
In a preferred embodiment, the first urging means
includes an air cylinder operable to keep each of the belts
in resiliently pressing contact with the veneer roll with a
predetermined force, while the take-up reel moving means
includes a pair of synchronously movable carriages removably
supporting the take-up reel at its opposite end portions,
gearing engaged with the carriages and a motor for driving
the gearing in response to the above command from the
control thereby to move the carriages synchronously upward.
In order to prevent the take-up reel from being
elevated because of the presence of a debris, such as piece
of veneer, which may cause a partial increase in the roll
diameter, the control generates the above command signal to
activate the reel moving means only when the take-up reel
has continued to rotate for a predetermined length of time
since the detecting means generated the signal to the
control. In the preferred embodiment of the invention, this
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63884-184
predetermined length of time corresponds to a quarter of a
complete turn of the take-up reel.
The roll member may have a plurality of roll
sections formed at locations corresponding to spaces between
any two adjacent belts and urged so that these roll sections
are resiliently pressed against the veneer roll.
In case of an embodiment wherein the detecting
means is arranged to detect the diametrical increment of
veneer roll by determining a predetermined amount of
movement of at least one belt from a predetermined position
thereof, a limit switch may be used which is disposed to be
operated by such movement of the belt.
Alternatively, according to the present invention,
the take-up reel may be disposed stationary and, instead of
the above reel moving means, any means for moving the belts
toward and away from the take-up reel may be employed. In
such a case, the control responding to a signal from the
detecting means transmits a command signal to activate the
above belt moving means so that the increment in diameter of
the veneer roll is compensated for.
The above and other objects, features and
advantages of the invention will become apparent to those
skilled in the art from the following description of
embodiments of the veneer reeling apparatus according to the
present invention, which description is made with reference
to the accompanying drawings, wherein:
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a front view of a preferred embodiment
of veneer reeling apparatus constructed according to the
present invention;
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1 FIG. 2 is a fragmentary plan view as seen in arrow direction
from dash-and-dot line A-A of FIG. 1;
FIG. 3 is a schematic side view showing part of the
apparatus of FIG. 1, as seen in arrow direction from dash-and-dot
line B-B of FIG. 2;
FIG. 4 is a fragmentary side view as seen in arrow direction
from dash-and-dot line C-C of FIG. 2;
FIG. 5 is a fragmentary side view as seen in arrow direction
from dash-and-dot line D-D of FIG. 1;
FIG. 6 is a schematic side view as seen in arrow direction
from dash-and-dot line E-E of FIG. 1;
FIG. 7 is a fragmentary front view as seen in arrow
direction from dash-and-dot line F-F of FIG. 2;
FIGS. 8 to 11 are fragmentary illustrative side views
similar to that of FIG. 4, but showing movement of a thread nozzle
of the apparatus;
FIGS. 12 and 13 are fragmentary side illustrative views
showing veneer reeling operation of the apparatus;
FIG. 14 is a fragmentary front view as seen in arrow
direction from dash-and-dot line G-G of FIG. 13, showing a
condition when a debris is wound with veneer sheet;
FIG. 15 is a fragmentary side illustrative view showing a
process of unwinding veneer sheet from take-up reel;
FIG. 16 is a schematic diagram showing a pneumatic system of
another embodiment of veneer reeling apparatus according to the
invention;
FIG. 17 is a fragmentary plan view of still another
embodiment of veneer reeling apparatus according to the present
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1 invention;
FIG. 18 is a fragmentary side view as seen in arrow
direction from dash-and-dot line H-H of FIG. 17;
FIG. 19 shows another embodiment of veneer peeling apparatus
of the invention;
FIG. 20 is a front view as seen in arrow direction from
dash-and-dot line J-J of FIG. 19;
FIG. 21 is a schematic side view showing still another
embodiment of veneer peeling apparatus of the invention;
FIGS. 22 and 23 are schematic side views showing a further
embodiment of veneer peeling apparatus of the invention;
FIG. 24 is a schematic side view showing still another
embodiment of veneer peeling apparatus of the invention;
FIG. 25 is a fragmentary plan view showing still another
embodiment of veneer reeling apparatus according to the present
invention;
FIG. 26 is a side view as seen in arrow direction from
dash-and-dot line N-N of FIG. 25;
FIG. 27 is a side view as seen in arrow direction from
dash-and-dot line P-P of FIG. 25;
FIG. 28 shows a prior art veneer reeling apparatus.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
Reference is made to the accompanying drawings, specifically
to FIGS. 1 to 15 showing a first preferred embodiment of the
present invention. As shown in FIGS. 1 and 2, the veneer peeling
apparatus includes a plurality of spaced endless conveyer belts 4,
or eight belts in the illustrated embodiment, each trained round a
front pulley 3 mounted on a common drive shaft 2 rotatably
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1 supported by bearings 1 fixedly mounted to a frame and driven by a
motor (not shown). Each belt 4 is also trained round a rear pulley
(not shown) mounted on a freely rotatable shaft (not shown either),
so that a veneer sheet 4 placed on the belts 4 is transferred
forward as indicated by arrows in FIG. 2. As schematically shown
in FIG. 2, a rotary encoder 43 is operatively connected to the
drive shaft 2 for monitoring the rotational speed of the shaft 2
and hence the traveling speed of the conveyer belts 4. Though not
shown in FIG. 2, the rotary encoder 43 is operatively connected to
a control 60 shown in FIG. 1.
The apparatus further has a take-up reel 35 extending above
and across the upper legs of the belts 4 for winding thereround a
veneer sheet 65 (FIG. 11) into a roll 66 (FIG. 13) and a touch roll
assembly 6. The latter assembly 6 includes a freely rotatable
shaft 13 located upstream of the front pulley shaft 2 and a
plurality of spaced touch rolls 5 carried on the shaft 13. The
touch rolls 5 are clad with urethane rubber covering and spaced
from one another such that annular grooves 7 and 8 are formed
between any two adjacent touch rolls, as most clearly shown in
FIG. 2, so as to provide spaces for the belts 4 to run and the tip
end of a thread nozzle 31 to enter, as will be described in a later
part hereof .
As shown in FIGS. 2 and 4, upstream of the touch roll
assembly 6 is located a bar 11 mounted on a shaft 10 rotatably
supported at opposite ends thereof by bearings 9 fixed to a frame
(not shown) of the apparatus. The shaft 10 carries at each end
thereof a swingable first arm 12 for rotation with the shaft 10.
As shown in FIG. 3, the shaft 13 of the touch roll assembl-:
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1 6 is rotatably supported at the opposite ends thereof by bearings
14 provided in the first arms 12, so that the shaft 13 is
vertically movable with swinging motion of the first arms 12 about
the shaft 10. An L-shaped second arm 18 having a vertical portion
18a is fixedly mounted to one of the first arms 12, or the
right-hand side arm as viewed in veneer conveying direction. There
is provided a compression spring 15 between each first arm 12 and
frame of the apparatus for supporting the first and second arms 12,
18 and the touch roll assembly 6 such that the first arms 12 are
maintained in a substantially horizontal position. Reference
numerals 16 and 17 designate stops for limiting rotation of the
first arm 12 in clockwise and counterclockwise directions,
respectively.
Just below the vertical portion 18a of L-shaped second arm
18 is located a pneumatic cylinder 19 with a piston rod 19a having
fixed at its outer end a load cell 20 which is operatively
connected to the control 60. The cylinder 19 is charged with air
under pressure the magnitude of which is such that the piston rod
19a exerts a predetermined upward force to the second arm 18 via
the load cell 20 that allows the touch rolls 5 to be pressed
against the take-up reel 35, or veneer roll 66 (FIG. 13) when such
a roll has been already formed, with a force of about 5 kilograms.
Such predetermined upward force effected by thus charging the air
cylinder 19 shall be referred to as "set upward force" hereinafter.
Incidentally, this "set upward force" may be obtained by
charging the cylinder 19 with air under pressure acting on the
piston rod 19a upwardly with a force that is equivalent to 5
kilograms times quotient obtained by dividing distance S1-S2 by
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1 distance S2-S3, wherein S1 and S2 denote axial centers of the shaft
13 of the touch roll assembly 6 and of the bar 11, respectively, as
seen in FIG. 3, and S3 represents a point of intersection between
an imaginary line connecting S1 and S2 and another imaginary line
passing through the center of the vertical portion 18a of the
second arm 18.
After air under the above pressure is charged in the
cylinder 19, both inlet and outlet ports of the cylinder are
sealingly closed with its piston rod 19a fully extended. By so
doing, when an external force is applied to the load cell 20 to
push the piston rod 19a downward, air within the cylinder 19 is
compressed and, accordingly, the piston rod 19a exerts a reaction
force in opposing or upward direction that is greater than the
above set upward force and proportional to the magnitude of the
above external force and hence to the distance for which the piston
rod 19 is pushed. This reaction force is detected by the load cell
20, which in turn generates to the control 60 a signal
representative of such reaction force.
The vertical portion 18a and the piston rod 19a have
longitudinal dimensions so that a slight clearance is formed
therebetween when no external force is applied to the load cell 20.
Referring now to FIGS. 2 and 4, there is provided a support
base 25 extending between the front pulley 3 and the touch roll
assembly 6 and straddling the lower legs of the conveyer belts 4.
The support base 25 has an air cylinder 26 fixed thereto in
association with each belt 4. Each belt 4 has on its inner surface
a backup plate 28 having substantially the same width as the belt 4
and rotatably supported at the upstream end thereof by a bearing
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1 27. Each cylinder 26 is charged with air under pressure, the
magnitude of which is established, with the weight of the plate 28
taken into account, so that the piston rod 26a of the cylinder 26
pushes the plate 28 to such an extent that each belt 4 is pressed
against the take-up reel 35, or veneer roll 66, with a
predetermined upward force of about 2.5 kilograms, namely 20
kilograms by all eight belts. It is noted that, in initial state
of the apparatus wherein the take-up reel 35 and the touch rolls 6
are located as shown in FIGS. 4 and 7, which initial state will be
detailed in later part hereof, the piston rod 26a is extended
partially out of its cylinder 26 and engaged in pressing contact
with its associated plate 28 so that, when the take-up reel 35 is
moved slightly upward, the piston rod 26a can extend further to
keep contact engagement with the plate 28, thereby allowing the
belts 4 to be in pressing contact with the reel 35. It is also
noted that, unlike air cylinder 19, each air cylinder 26 is so
arranged that the force with which each belt 5 presses against the
take-up-reel 35, or against veneer roll 66, will not be varied
remarkably by slight movement of the piston rod 26a relative to its
cylinder. Such arrangement may accomplished by sealing the outlet
port of the cylinder 26, but connecting the inlet port thereof to a
reducing valve (not shown) with a relatively long hose so that a
larger amount of air must be compressed by downward movement of the
piston rod 26a.
As indicated by phantom lines in FIG. 2, a plurality of
thread nozzles 31 is disposed adjacent the take-up reel 35 at
locations corresponding to the respective grooves 8, each having a
nozzle end 31a whose outer diameter is smaller than the width of
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1 the groove 8 so as to be inserted thereinto as required. The
nozzle 31 is operable to initially eject a thread 31 by air jet
issued from its end 31a and then to allow the thread to be pulled
out tautly during veneer reeling operation. Furthermore, each
thread nozzle 31 is movable by any appropriate means such as air
cylinder in both vertical and horizontal directions, as will be
described more in detail later herein.
Referring back to FIG. 1, a pair of uprights 36 is located
adjacent the opposite ends of the touch roll assembly 6, and a pair
of screws 38 operatively connected by a shaft 40 via bevel gears 39
is provided adjacent the uprights 36. A servo-motor 41, which is
operable from a signal transmitted by the control 60, is connected
to one of the bevel gears 39 for rotating both screws 38
synchronously. A rotary encoder 42 is operatively connected to the
shaft 40 for counting the number of rotations thereof thereby to
determine the distance that the take-up reel 35 has moved from its
initial state position as will be explained hereinafter. This
rotary encoder 42 is also connected to the control 60.
A support block 45 having formed therein internal thread
(not shown) is engaged with each screw 38 and disposed through an
opening 46 formed in each upright 36 for guided movement along
vertical guide surfaces 47 by the aid of linear bearings 48 fixed
to the support block 45, as shown a.n FIG. 5. A take-up reel
carriage 51 is fixed to the inner end of each support block 45.
The reel carriage 51 has formed therein a V-shaped support surface
52 for supporting a bearing 33 mounted at each end of a shaft 35a
on which the take-up reel 35 is fixedly mounted, as schematically
shown in FIG. 6. By so arranging, the take-up reel 35 is rotatable
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1 relative to the carriages 51 and movable vertically with the
support blocks 45 along the screws 38 while maintaining parallel
relationship to the touch roll shaft 13. As it is apparent to
those skilled in the art, the take-up reel 35 is removably carried
on the carriages 51.
The following will describe the manner in which the control
60 operates on the motor 41 for controllably driving the screws 38
thereby to move the take-up reel carriages 51.
When load detected by the load cell 20 increased to exceed
the above set upward force of the cylinder 19 by about 10 percent
while the carriages 51 are moving downward with the pulley drive
shaft 2 kept at a stop, which stop condition is detected by the
rotary encoder 43, the control 60 then responding to a signal from
the load cell 20 representative of such an increase of the load
generates a signal commanding the motor 41 to stop and then to
operate so as to rotate the screws 38 in the direction that causes
the carriages 51 to be elevated until load detected by the load
cell 20 becomes smaller than the set upward force of the cylinder
19.
On the other hand, when load detected by the load cell 20 is
increased exceeding the set upward force of the cylinder 19 by
about 10 percent while the pulley drive shaft 2 is being rotated
and also if the detected load continues to be so while the take-LD
reel 35 rotates for a period of time corresponding to a
predetermined rotation angle, e.g. a quarter of a complete turn c~
the reel 35, the control 60 generates a signal commanding the motor
41 to operate to rotate the screws 38 in the direction that causes
the carriages 51 to be elevated. This elevation is continued un~~_1
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1 load detected by the load cell 20 becomes smaller than the set
upward force of the cylinder 19 and also if this condition
continues to be so while the take-up reel 35 makes a quarter turn.
While the conveyer belts 4 travel substantially at a
constant speed, the time t during which the take-up reel 35 makes a
quarter turn is lengthened with an increase in diameter of veneer
roll 66. Incidentally, the time t can be figured out as follows.
The distance that the outer periphery of veneer roll 66 moves
during the length of time t is zt, wherein z represents the speed
at which the belts 4 move, and the circumference of veneer roll 66
is expressed by 2n(x+y), wherein x represents the distance for
which the carriages 51 are moved from their initial state position
and y the radius of the reel 35, thus (x+y) represents the current
radius of veneer roll 66. Since zt corresponds to a quarter of
2n(x+y), t is expressed by 2n(x+y)/2z. In operation, the time t is
calculated by the control 60 receiving information on the distance
x measured by the rotary encoder 42 and the speed z monitored by
the rotary encoder 43.
It is noted that the control 60 may be operable on the motor
41 from command signals generated by manual operation on a control
panel by a machine operator, as will be explained in later part
hereof .
The apparatus thus constructed is set in its initial state
as follows.
With the pulley drive shaft 2 kept at a stop, the machine
operator manually starts the motor 41 to rotate the screw 38 so as
to bring the carriages 51 to a position higher than that shown in
FIG. 1. Then, the take-up reel 35 is set in position by placing
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1 its bearings 33 on V-shaped support surfaces 52 of the carriages as
shown in FIG. 6. The screws 38 are rotated by manually operating
the motor 41 to lower the carriages 51 and the take-up reel 35 is
brought into contact with the conveyer belts 4 and the touch rolls
5. By allowing the take-up reel 35 to move further downward, the
touch rolls 5 and the belts 4 are forced downward and, therefore,
the first arms 12 carrying the shaft 13 for the touch rolls 5 is
caused to swing clockwise as seen in FIG. 3 and the lower end of
the vertical portion 18a of the second arms 18 presses the load
cell 20. Consequently, the piston rod 19a to which the load cell
is attached is pushed into the cylinder 19 and air under
pressure in the cylinder 19 is compressed. Accordingly, the piston
rod 19a is urged upward by a reaction force that is greater than
the set upward force and the magnitude of which is commensurate to
the extent of the above compression. Thus, the load cell 20 is
subjected to a downward force from the second arm 18 and
simultaneously to an upward force from the piston rod 19a.
As the load detected by the load cell 20 is further
increased to exceed the set upward force by about 10 percent, the
20 control 60 then responding to a signal representative of such an
increase of the load generates a signal commanding the motor 41 to
stop and then to operate so as to rotate the screws 38 in the
direction that causes the take-up reel 35 to be elevated. As the
take-up reel 35 is raised gradually, the force to push down the
touch rolls 5 and hence the force acting on the load cell 20 is
reduced and the piston rod 19a is allowed to move upward under ti,:e
influence of compressed air in the cylinder 19 which is then
greater than the set upward force. Therefore, the first arm 12 _s
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1 swung in counterclockwise direction as seen in FIG. 3 and the touch
roll assembly 6 carried by the first arm 12 is allowed to move
upward while maintaining pressing contact with the take-up reel 35.
As the piston rod 19a moves out of the cylinder 19 gradually, the
force acting on the load cell 20 is reduced. As described earlier,
when load detected by the load cell 20 becomes smaller than the set
upward force of the cylinder 19, the control 60 generates a signal
to stop the motor 41, thus stopping the upward movement of the reel
carriages 51.
As a result of the above operational procedure for
establishing the initial state of the apparatus, the take-up reel
35 is set in position as shown in FIG. 7. That is, the touch rolls
5 are engaged in pressing contact with the peripheral surface of
the take-up reel 35 and the conveyer belts 4 urged by the cylinders
26 by way of the plates 28 are resiliently pressed against the reel
35.
The following will describe veneer reeling operation of the
apparatus while referring to FIGS. 8 to 13.
With the apparatus set in the above-described initial state
shown in FIGS. 4 and 7, firstly each nozzle 31 is activated to
issue an air jet with a thread 30 from the nozzle end 31a for a
short period of time to allow the thread to be positioned over the
take-up reel 35 and the touch rolls 5 with its leading end located
between the touch rolls 5 and the bar 11, as shown in FIG. 8.
Subsequently, each nozzle 31 is moved down below the belts 4 as
shown in FIG. 9 and then shifted horizontally to a position where
the nozzle end 31a is located within the groove 8 just below the
take-up reel 35 with the thread 30 drooping across the belts 4, as
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1 shown in FIG. 10. The above nozzle operations may be performed by
manual operation on a control panel by the machine operator. With
the thread 30 located as shown in FIG. 10, resistance is applied to
the thread 30 at any appropriate position upstream of the nozzle
end 31a so that the thread is kept taut when it is pulled out of
the nozzle. Then, the motor (not shown) for the front pulley shaft
2 is started to initiate conveying movement of the belts 4.
Therefore, the take-up reel 35 against which the belts 4 are
pressed is rotated by frictional force therebetween, while the
touch rolls 5 engaged in contact with the reel 35 are also rotated
by frictional force from the reel.
Referring to FIG. 11, reference numeral 65 designates a
veneer sheet 65 peeled by a rotary veneer lathe (not shown) at a
speed corresponding to the traveling speed of the conveyer belts 4
and having a nominal length of six feet (or about 1,800 mm) as
measured along the fiber orientation of the wood veneer sheet, or
across the direction in which the sheet is moved on the belts 4.
As the leading end of the veneer sheet 65 reaches the threads 30,
the moving sheet bends the threads 30 as shown in FIG. 12, and the
sheet passing between the take-up reel 35 and the touch rolls 5 is
wound continuously round the reel 35 while being guided safely by
the threads 30. Thus, a roll 66 of veneer sheet is formed round
the take-up reel 35 as shown in FIG. 13.
As the reeling operation continues, the veneer roll diameter
is increased progressively. Since the take-up reel 35 remains its
current vertical position, the belts 4 and the touch rolls 5 are
forced downward with an increase in diameter of the veneer roll 65.
Therefore, the first arm 12 movable with the touch rolls 5 is swung
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1 clockwise as seen in FIG. 3, so that the load cell 20 is pushed and
the piston rod 19a is moved gradually into the cylinder 19.
Consequently, air in the cylinder 19 is compressed to increase the
pressure therein, so that load detected by the load cell 20 becomes
greater and eventually exceeds the set upward force.
If the load detected by the load cell 20 continues to be in
excess of the set upward force by about 10 percent while the
take-up reel 35 rotates a quarter of its complete turn, the control
60 generates a signal to the motor 41 to rotate the screws 38 in
the direction that causes the carriage 51 to be elevated with the
take-up reel 35 carried thereby. With the take-up reel 35 thus
elevated, the pressure acting on the touch rolls 5 from veneer roll
66 is decreased and the first arm 12 is allowed to swing back in
counterclockwise direction. The force exerted by the second arm
portion 18a to the load cell 20 is also decreased. The elevation
of the take-up reel 35 is continued until the load detected by the
load cell 20 becomes smaller than the set upward force of the
cylinder 19 and also if this condition continues to be so while the
take-up reel 35 makes a quarter turn.
As it is now apparent from the foregoing, controllably
elevating the take-up reel 35 in response to an increment in
diameter of veneer roll 66 makes it possible to allow the touch
rolls 5 to be pressed against the veneer roll 66 with an optimum
force of about 5 kilograms.
On the other hand, the piston rod 26a acting on each
conveyer belt 4 via plates 28 is also pushed into its associated
cylinder 26 by an increase of reeled diameter of the veneer roll
66. However, since the upward force exerted by the cylinder 26
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1 remains substantially constant as described earlier, the force
acting on the veneer roll 66 from the belts 4 remains unchanged.
Furthermore, when the carriages 51 are raised by the above motor
operation, the piston rod 26a is extended back outward from its
cylinder 26 to maintain its pressing contact with the plate 28, so
that the belt 4 is kept in pressing contact with the veneer roll 66
for providing frictional force necessary to driving the roll.
As it is now apparent to those skilled in the art, veneer
reeling operation is performed with the conveyer belts 4 and the
touch roll 5 kept in pressing contact with veneer roll 66 and the
force with which the touch rolls 5 are pressed against the veneer
roll is constantly monitored by the load cell 20 and controlled to
be maintained substantially constant. Additionally, veneer roll 66
is positively driven to rotate by frictional force from the belts
4, so that the length of line-to-circle contact therebetween as
measured in veneer conveying direction is longer than
circle-to-circle contact in the case of the conventional apparatus
of FIG. 28. Therefore, the magnitude of stress applied to a unit
area of veneer sheet is advantageously reduced and harmful
stressing of veneer sheet as encountered in the conventional
apparatus is prevented. Consequently, the problems as described
earlier with reference to FIG. 28, such as deviation from a
straightforward course along the belts 4 which may result in
collision against a frame, formation of folds in veneer sheet
causing breakage thereto can be solved successfully.
In winding a thin and hence weak veneer sheet with a
thickness of about 0.6 mm, portions of the sheet between any two
adjacent conveyer belts 4 tends to sag by its own weight, but such
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CA 02247236 1998-09-11
1 portions are pressed against veneer roll 66 with a moderate force
by the touch rolls 5 clad with urethane rubber covering. Thus,
smooth and stabilized reeling operation is achieved in handling a
thin veneer sheet.
Now reference is made to FIG. 14 showing a condition in
which a debris 67, e.g. a piece of veneer produced by trimming with
scarf knives provided on opposite sides of a veneer lathe (not
shown), is present on veneer sheet 65. In such a case, veneer
sheet 65 projects radially outward at the location where the piece
67 is caught between the sheet 65 and the veneer roll 66, and a
belt 4 and touch rolls 5 adjacent such projection are forced
downward, as clearly seen in FIG. 14. Accordingly, a gap is formed
between the touch rolls 5 and veneer roll 66 in the area other than
the projection. Though the belt 4 just below the debris 67 is
forced down while pushing its associated piston rod 26a, all the
belts 4 maintain pressing contact with veneer roll 66 with
substantially the same pressure. Thus, trouble-free reeling
operation is accomplished even when a veneer debris is caught and
wound together with a veneer sheet.
Additionally, when the touch rolls 5 is forced down by the
presence of any debris 67, the first arm 12 is swung and the load
cell 20 may be pressed to such an extent that a load detected by
the load cell 20 exceeds the set upward force by about 10 percent.
However, since the debris 67 is usually a small piece which moves
past the touch roll 5 rapidly before the take-up reel 35 makes a
quarter turn, position of the reel 35 remains unchanged without
being influenced by such debris.
Reeling operation is continued until the veneer roll 66
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CA 02247236 1998-09-11
1 reaches a predetermined diameter. When the reeling has been
completed, the take-up reel 35 with veneer roll 66 is removed from
the carriages 51 and transferred to any location for the subsequent
unreeling process. A manner of unreeling is exemplified in
FIG. 15. The take-up reel 35 is rotatably supported by a pair of
carriages (not shown) similar to the carriages 51 each having a
V-shaped groove, and a plurality of belts 71 driven by a pulley 70
in arrow direction is pressed against the peripheral surface of
veneer roll 66 with an appropriate pressure by any suitable means
(not shown). By so doing, veneer roll 66 is rotated in unwinding
direction as indicated by arrow. While veneer sheet 65 is being
unreeled from roll 66, the threads 30 are unwound synchronously
with the traveling speed of the belts 71 to be rewound on bobbins
72 each located below a space between any two adjacent belts.
Depending on the kind or species of veneer to be reeled,
however, when veneer sheet continues to be stressed between the
belts 4 and veneer roll 66, the sheet may be stretched in the
region upstream of the veneer-roll 66 to such an extent that the
sheet movement is deviated from straightforward course along the
belts 4 and also that stretching causes slack in the sheet which
may result in formation of folds as encountered in the conventional
apparatus.
The following will describe a second embodiment of veneer
reeling apparatus according to the invention which is designed as
an improvement over the first preferred embodiment.
The second embodiment differs from the first preferred
embodiment only in pneumatic system for the cylinders 26. For the
sake of description, eight conveyer belts 4 are arranged in two
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CA 02247236 1998-09-11
1 groups; namely, four belts on the left-hand side as seen in veneer
conveying direction (see FIG. 2) which will be referred to as belts
of a first group, while the remaining four belts on the right-hand.
side as belts of a second group.
Referring to FIG. 16, the apparatus includes an air
compressor 76 connected to two pairs of reducing valves 77, 78 and
79, 80 which are in turn connected to solenoid-operated valves 81,
82, respectively, for selectively changing the flow direction of
air under reduced pressure. The solenoid valves 81, 82 are
operatively connected to the air cylinders 26 for the conveying
belts of the first and second groups, respectively. For the sake
of description, the cylinders 26 for the belts 4 of the first and
second groups are referred to as cylinders of the first and second
groups, respectively. The solenoid valves 81, 82 are electrically
connected to a control 60a. It is noted that the control 60a
performs the function of controlling the operation of the solenoid
valves 81, 82, as will be described in detail below, as well as the
control function as described with reference to the first preferred
embodiment. The reducing valves 77 and 79 are adapted to reduce
the pressure of compressed air from the air compressor 76 to a
first pressure, while the reducing valves 78 and 80 to a second
pressure. The first pressure adjusted by the reducing valves 77,
79 is of such a magnitude that, when introduced into each air
cylinder 29 for the conveyer belts 4 of either one of the two
groups, allows each such belt to exerts a pressing force of about 5
kilograms against the take-up reel 35 or veneer roll 66, namely 20
kilograms by four belts. The second pressure from the reducing
valves 78, 80 is of such a magnitude that only supports the plate
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CA 02247236 1998-09-11
1 28 for each belt 4 and allows each belt to exert very little
pressing force against the take-up reel 35 or veneer roll 66.
The following will describe operation of the apparatus of
the second embodiment.
To initiate reeling operation of the apparatus, machine
operator provides a start signal to the control 60a by manual
operation on a control panel. In response to such signal, the
control 60a operates the solenoid valves 81, 82 to establish flow
lines that allow air under the first pressure to be supplied to the
air cylinders 26 of the first group and air under the second
pressure to the cylinders 26 of the second group, respectively.
Then, the operator manually transmits a signal to start the motor
for the front pulley shaft 2, thus activating the conveyer belts 4.
Upon starting the belts 4, the control 60a is operated to calculate
moving distance of the belts 4 based on the information of belt
running speed obtained from the rotary encoder 43 and time elapsed.
When the moving distance according to the calculation becomes a
predetermined valve, e.g. about 500 mm, the control 60a generates a
command signal to simultaneously change the solenoid valves 81, 82
so that air under the second pressure is supplied to the air
cylinders 26 of the first group and air under the first pressure to
the cylinders 26 of the second group, respectively. Whenever the
distance moved by the belts 4 reaches 500 mm as counted after the
previous changing of the solenoid valves 81, 82, the control 60a
operates to change the flow lines through the solenoid valves 81,
82. Thus, such alternating operation is repeated each time the
conveyer belts 4 move a distance of about 500 mm.
In operation of the apparatus, when the air cylinders 26 of
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CA 02247236 1998-09-11
1 the first groups is supplied with the first pressure and the
cylinders 26 of the second group with the second pressure, namely
when the belts 4 of the first group are pressed against veneer roll
66 while the belts of the second group are merely in touch
therewith, slack tends to be produced in veneer sheet 65 behind the
veneer roll 66 in the region of the belts 4 of the first group.
Should the belt 4 of the first group maintain pressing contact with
the veneer roll 66 for a long time, the slack may grow into a large
wave which may result in the formation of harmful folds. According
to this embodiment, however, wherein the pressure with which the
belts 4 of the first group are pressed against the veneer roll 66
is reduced substantially zero after the belts 4 has moved a
distance of about 500 mm, the veneer sheet 65 is subjected no more
to a stressing force in the region of the first group conveyer
belts 4, and the veneer sheet is wound as slackened without the
slack being accumulated into a large wave form.
If winding of veneer sheet 65 as slackened is continued in
either one end portions of veneer roll 66 because of occasional
specific property of the veneer sheet being reeled, the above one
end portion of veneer roll becomes larger in diameter than the
other end portion, so that the veneer roll may result in a slightly
tapered form. In such a case, the touch rolls 5 are forced by the
larger end of the taper and, if load applied to the load cell 20 is
increased to exceed the set upward force by about 10 percent, the
reel carriages 51 are elevated until the load is reduced less than
the set upward force. Such movement of the carriages 51 is
repeated until the slack is produced and wound no more and,
therefore, the veneer roll 66 becomes substantially cylindrical.
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CA 02247236 1998-09-11
1 Veneer roll 66 thus formed has of course one end portion loosely
wound than the other end portion.
As a matter of course, the take-up reel carriages 51 are
raised in the above embodiment in the same manner as in the first
preferred embodiment in accordance with signals which are generated
by the load cell 20 to the control 60 and representative of an
increment in diameter of a veneer roll 66.
The following will describe a third embodiment of veneer
reeling apparatus according to the invention with reference to
FIGS. 17 and 18, wherein elements corresponding to elements of the
first embodiment are designated by like reference numerals. The
third embodiment differs from the first embodiment primarily a.n
that it dispenses with the touch roll assembly 6 and its associated
parts such as first and second arms 12, 18, load cell 20 and
cylinder 19.
Referring to FIG. 17, the apparatus comprises a plurality of
conveyer belts 4 which are similar to, but more in number than
those in the first embodiment and spaced at smaller intervals.
Each belt 4 is trained round a front pulley 3 mounted on a common
drive shaft 2 and driven by a motor (not shown). As shown in FIG.
18. there is provided a support base 25 extending behind the pulley
3 and straddling the lower legs of the conveyer belts 4. On the
support base 25 are fixed an air cylinder 26 corresponding to each
belt 4. Each belt 4 has on its inner surface a backup plate 28
having substantially the same width as the belt 4 and rotatably
supported at the upstream end thereof by a bearing 27. Each
cylinder 26 is charged with air under pressure, the magnitude of
which is established such that the piston rod 26a of the cylinder
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CA 02247236 1998-09-11
1 26 pushes the plate 28 to such an extent that each belt 4 is
pressed against the take-up reel 35, or veneer roll 66, with a
predetermined upward force, namely about 20 kilograms by all the
belts 4. It is noted that the piston rod 26a is extended partially
out of its cylinder 26 and engaged in pressing contact with its
associated plate 28 so that, when the take-up reel 35 is moved
slightly upward, the piston rod 26a can extend further to keep
contact engagement with the plate 28 with substantially the same
force, thereby keeping the belts 4 to be in pressing contact with
the take-up reel 35 or veneer roll 66.
A limit switch 86 is fixed to a frame (not shown) at any
appropriate position where it can be stricken or turned on by a
plate 28 for any one of the belts 4 when it is moved down together
with its associated belt to a predetermined position. As indicated
by phantom line in FIG. 18, the limit switch 86 is electrically
connected to a control 60b to generate thereto a signal when the
switch is turned on. Additionally, a plurality of thread nozzles
31 is disposed adjacent the take-up reel 35 between any two
selected adjacent belts for feeding therefrom a thread 30 as in the
first embodiment.
The control 60b operates on the motor 41 (FIG. 1) for
controllably driving the screws 38 (FIG. 1) as follows.
When the limit switch 43 is turned on by the plate 28
lowering together with its belt 4 while the carriages 51 are moving
downward and the pulley drive shaft 2 kept at a stop, the control
60b then responding to a signal from the limit switch 43 generates
a command signal to stop the motor 41 and then to operate the motcr
so as to rotate the screws 38 in the direction that causes the
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CA 02247236 1998-09-11
1 carriages 51 to be elevated until the limit switch 43 generates the
signal no more.
On the other hand, when the limit switch 43 is actuated
while the pulley drive shaft 2 is being rotated and also if the
limit switch 43 remains on while the take-up reel 35 rotates, e.g.,
a quarter of a complete turn thereof, the control 60b generates a
signal commanding the motor 41 to operate to rotate the screws 38
in the direction that causes the carriages 51 to be elevated. This
elevation is continued until the limit switch 43 is turned off and
also if this condition continues while the take-up reel 35 makes a
quarter turn.
The apparatus of the third embodiment is set in its initial
state as follows.
With the pulley drive shaft 2 kept at a stop, the machine
operator manually starts the motor 41 to rotate the screw 38,
bringing the carriages 51 to a position higher than that shown in
FIG. 1. After the take-up reel 35 is set in position on the
carriages 51, the screws 38 are rotated to lower the carriages 51
with the reel 35. As the take-up reel 35 is brought into pressing
contact with the conveyer belts 4, the plates 38 are swung down
while forcing the piston rod 26a into the cylinder 26. By allowing
the take-up reel 35 to move further downward, the limit switch 86
is turned on and, therefore, the control 60b generates a signal
commanding the motor 41 to stop and then to operate to rotate the
screws 38 in the direction that causes the take-up reel 35 to be
raised. As described earlier, when the limit switch 86 is turned
off, the motor 41 is stopped and the upward movement of the take-up
reel carriages 51 is also stopped. As a result of the above manual
- 27 -
CA 02247236 1998-09-11
1 operation, the take-up reel 35 is set in its initial state position
as shownPin FIG. 18.
Veneer reeling is initiated with threads 30 previously
located over the take-up reel 35 and the nozzles 31 shifted to the
position indicated by solid line as shown in FIG. 18. As the
reeling operation continues and a veneer roll 66 increases its
diameter, the belts 4 and the plates 28 are forced down until the
limit switch 86 is stricken by one of the plates. If the limit
switch 86 remains on while the take-up reel 35 rotates a quarter of
its complete turn, the control 60 is operated to generate a signal
to the motor 41, which in turn rotates the screws 38 in the
direction that causes the carriages 51 to be elevated with the
take-up reel 35. The elevation of the carriages 51 is continued
until the limit switch is turned off and also if this off condition
remains while the take-up reel 35 makes a quarter turn.
If a debris 67 present on an incoming veneer sheet 65 is
wound together therewith, belts 4 adjacent such debris are forced
down while forcing the piston rods 26a into the cylinders 26, but
all the belts 4 maintain pressing contact with the veneer roll 66
with substantially the same pressure as in the first embodiment
and, therefore, the veneer roll 66 rotates substantially at a
constant peripheral speed. Though the limit switch 86 may be
actuated by the presence of any debris 67 wound with veneer sheet,
the position of the take-up reel 35 remains unchanged without being
influenced by such debris because it is usually a small piece
moving past the contact area between the belt 4 and the veneer roll
66 rapidly before the reel 35 makes a quarter turn.
As is apparent to those skilled in the art, the arrangement
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CA 02247236 1998-09-11
1 described with reference to FIG. 16 may be employed in the above
third embodiment.
The following will further describe other various
embodiments and modifications of the invention, wherein elements
corresponding to elements of the above embodiments are designated
by like reference numerals.
(1) FIGS. 19 and 20 show an embodiment which dispenses with
touch rolls 5, as well as plates 28 urged by cylinders 26 for
pressing the belts 4 against the take-up reel 35 or veneer roll 66.
In this embodiment, a series of pulleys 91, which are
fixedly mounted on a common pulley shaft and round which conveyer
belts 4 are. trained, is rotatably supported by bearings (not shown)
in the respective pulley support blocks 92. Each support block 92
is in turn vertically movably guided by a guide member 93 fixed to
a frame (not shown). Disposed below the pulley support block 92 is
an air cylinder 94 having a piston rod 94a pressed against the
support block 92. As shown in FIG. 20, a gear 95 is fixed on the
pulley shaft and operatively connected by a cogged belt 98 with
another gear 97 fixed on a shaft 96 driven by a common stationary
motor (not shown). Thus, the pulleys 91 are allowed to move
vertically along the guide member 93 while being driven from the
motor. As apparent from FIG. 19, the take-up reel 35 or veneer
roll 66 is rotatable by friction due to contact with the belts 4
driven by the pulleys 91. Air pressure in the cylinders 94 is
established so that the take-up reel 35 or veneer roll receives a
pressing force of about 20 kilograms from the belts 4 irrespective
of the position of the piston rod 94a relative to its cylinder 94
as in the first to third embodiments.
- 29 -
CA 02247236 1998-09-11
1 To detect the displacement of belt 4 caused by an increase
in diameter of veneer roll, a limit switch similar to the switch 86
of FIG. 18 may be provided to be actuated by contact with the belt
4.
(2) Load cell 20 used in the first and second embodiments
may be replaced by a limit switch 99 arranged so as to be actuated
by an arm 18a fixed to the first arm 12 for movement therewith, as
shown in FIG. 21. Though a limit switch may be inferior to a load
cell in detecting accuracy, it serves for the purpose in reeling a
relatively thick sheet of veneer.
(3) Air cylinder 26 in the first embodiment may be
substituted by a compression spring constructed and disposed to
exert a force that keeps the belts 4 in pressing contact with the
take-up reel 35 or veneer roll 66.
(4) In the third embodiment of FIGS. 17 and 18, air cylinder
26 may be replaced by a compression spring if the conveyer belts 4
are not arranged into two groups for alternately changing the
pressure acting on the belts as in the second embodiment.
(5) Instead of the limit switch 86 used in the third
embodiment, a reflective type photoelectric switch may be employed
for detecting downward displacement of belt 4 caused by an increase
in diameter of veneer roll 66.
(6) As means for detecting an increment of veneer roll
diameter, a laser beam may be employed which is directed toward t~~e
axial center of the take-up reel 35 so that the beam is emitted
against the outer peripheral surface of veneer roll 66 and
reflected beam is received for determining a progressive increase
of veneer roll diameter
- 30 -
CA 02247236 1998-09-11
1 (7) While in the second embodiment and a modification of the
third embodiment the first and second pressures of the cylinders 26
acting on the belts 4 of two different groups are alternately
changed each time the belts 4 move a distance of about 500 mm, this
distance may be changed as required depending on the species of
veneer or thickness of veneer sheet be reeled. Alternatively,
changing between the first and second pressures may be performed
after elapse of a predetermined length of time.
(8) While in the first embodiment the cylinder 19 is charged
with air under pressure of a magnitude that allows the touch rolls
5 to be pressed against the take-up reel 35 or veneer roll 66 with
a force of about 5 kilograms, this pressure may be changed as
required depending on the species of veneer or thickness of veneer
sheet.
(9) Likewise, the pressure in the air cylinders 26 for
urging the conveyer belts 4 against the take-up reel 35 or veneer
roll 66 in the first and second embodiments may be changed as
required depending on the species veneer or thickness of veneer
sheet.
(10) It is known to those skilled in the art that threads 30
serve as effective guide in winding in particular a weak veneer
sheet or discrete veneer sheets cut previously into any desired
size and fed successively. When winding a relatively strong veneer
sheet, however, the reeling apparatus may dispense with thread
nozzles 31. In this case, initial reeling of veneer sheet round
the take-up reel 35 may be manually performed by winding a couple
of turns of the leading end portion of the sheet and then
initiating automatic reeling with the conveyer belts 4 activated.
- 31 -
CA 02247236 1998-09-11
1 (11) In the first to third embodiments, for the control to
provide a command signal to the motor 41 for elevating the take-up
reel 35 and also for stopping its elevation, it is required that
the reel 35 should make a quarter turn while the load cell 20 or
the limit switch 86 remains its actuated state. If there is no
fear of a debris being wound with veneer sheet, however, the
requirement of time for the take-up reel 35 to make a quarter turn
may be eliminated. Alternatively, the time may be changed
depending on working conditions.
(12) In the second embodiment and a modification of the
third embodiment each having two different groups of conveying
belts 4, it may be so arranged by further modification thereof that
any selected number of belts, as counted from the respective sides
of the array of belts, are associated with air cylinders 26 of the
first and second groups connected to the solenoid valves 81 and 82,
respectively, so that the first and second pressures of the
cylinders 26 acting on the selected belts 4 are alternately changed
each time the belts 4 move a predetermined distance. In such a
case, the remaining intermediate belts 4 should be arranged so as
to receive a substantially constant force corresponding to the
first pressure of the cylinder.
(13) The pair of screws 38 as means for moving the take-up
reel carriages 51 may be substituted by other means such as air
cylinders.
(14) Referring to FIGS. 22 and 23, these illustrate an
embodiment which operates in a manner similar to the second
embodiment, wherein air cylinder 26 as means for pressing belts 4
against the take-up reel 35 or veneer roll 66 is replaced by cam
- 32 -
CA 02247236 1998-09-11
1 and compression spring.
In the drawings, reference numeral 106 designates a
swingable plate located just below each plate 28 and swingably
supported by a bearing 107. A compression spring 108 is fixedly
mounted between the distal end portions of the two plates 28 and
106. For the sake of description, the plate 28 is referred to as
first plate and the plate 106 as second plate, respectively,
hereinafter. A shaft 109 extends below the second plate 106 where
the spring 108 is fixed. The shaft 109 is rotatably supported by
stationary bearings (not shown) and driven by a servo motor (not
shown). In this embodiment, there is provided a total of 16
conveyer belts 4 which are arranged into first and second groups as
in the second embodiment (FIG. 16). A cam 110 as shown in FIG. 22
is fixedly mounted on the shaft 109 for rotation therewith for each
plate 28 for the first group conveyer belts 4 and a cam 111 is
fixed on the same shaft 109 for each plate 28 for the second group
belts 4. As seen from comparison of FIGS. 22 and 23, the cams 110
and 111 have the same profile, but are disposed in symmetrical
arrangement such that one of the cams 110 and 111 is in a position
rotated by a half turn from that of the other cam.
In a position of the apparatus as shown in FIGS. 22 and 23,
the second plates 106 are raised by the cams 110 while compressing
the springs 108 thereby to urge the first plates 28 upward, so that
belts 4 of the first group are pressed against the take-up reel 35
with a relatively large force, while the second plates 106 for the
second group are in their lowered position with the springs 108
less compressed so that belts 4 of the second group are pressed
against the reel 35 with a relatively small force. The magnitude
- 33 -
CA 02247236 1998-09-11
1 of forces applied to the take-up reel 35 in the above two positions
of the cams 110 and 111 may be determined by selecting springs with
the desired spring constant.
There is provided a control (not shown) which is operable to
generate a signal commanding a motor (not shown) to rotate the
shaft 109 a half turn after the belts 4 move a predetermined
distance, e.9., about 500 mm. Thus, the conveyer belts 4 of the
first and second groups press the take-up reel 35 with a large
force and a small force alternately each time the belts moves the
above distance. Thus, the apparatus of this embodiment provides an
effect similar to that obtained in the second embodiment.
(15) Referring to FIG. 24, this shows an embodiment
combining the features of the embodiments of FIG. 19 and of FIGS.
22 and 23. Namely, the air cylinder 94 (FIG. 19) is replaced by a
plate 106 supported by bearing 107, a compression spring 108 and
cams 110 and 111 fixedly mounted on a shaft 109 driven by motor
(not shown) of FIGS. 22 and 23. The conveyer belts 4 are arranged
into first and second groups of belts which are pressed against the
take-up reel 35 with large and small forces alternately.
(16) In the above-described embodiments, the take-up reel 35
is adapted to be elevated by rotating the screws 38 in accordance
with an increase in diameter of veneer roll 66. It may be so
arranged, however, that the take-up reel 35 is provided stationary
and, instead, the conveyer belts 4 are movable with a diametrical
increase of veneer roll 66.
Referring to FIGS. 25, 26 and 27, reference numeral 116
designates a pair of uprights disposed on opposite sides of an
array of conveying belts 4. These belts 4 are arranged into two
- 34 -
CA 02247236 1998-09-11
1 groups as in the second embodiment (FIG. 16). A freely rotatable
shaft 117 is supported at its end portions by bearings (not shown)
in the uprights 116 and a pair of arms 119 (only one shown) is
swingably mounted at the proximal ends thereof on the shaft 117 via
bearings 118. A shaft 121 is freely rotatably supported by
bearings 120 in the distal end portion of each arm 119 and carries
thereon a series of spaced pulleys 122, namely as many as 16
pulleys. On the other hand, the shaft 117 carries thereon the same
number of pulleys 123 (FIG. 27) and each of the belts 4 is trained
round the corresponding pulleys 122 and 123.
Though not shown fully in the drawings, a pulley is mounted
on the shaft 117 between each two adjacent pulleys 123 and a belt
124 is trained over the former pulley and its corresponding pulley
(not shown) located at upstream end of the upper leg of the belt
124. A sprocket wheel 125 is fixed on one end of the shaft 117 and
operatively connected to a motor 126 by chain 127 for driving the
shaft 117, thus moving the conveyer belts 4 and 124 in arrow
direction.
A support plate 128 is attached between the arms 119 at
their bottoms for swinging therewith. A plate 130, similar to the
plate 28 of the first embodiment, having the same width as the belt
4 is disposed just below each belt and supported swingably about a
bearing 129. An air cylinder 131 is fixed on the above support
plate 128 at such a position that its piston rod, when extended, is
engageable with the lower surface of each plate 130 at its distal
end portion. These air cylinders 131 are grouped to correspond to
the first and second groups of conveyer belts 4 and arranged in the
manner as described with reference to FIG. 16 so that the cylinders
- 35 -
CA 02247236 1998-09-11
1 131 are alternately supplied with the first and second pressures.
Two limit switches 132 (only one shown) are also fixed on the
support plate 128 just below the plates 130 at the opposite
outermost sides of the array of belts 4. Furthermore, below each
of the swingable arms 119 is provided another air cylinder 133
having its piston rod 133a connected by a pin 134 to the bottom of
the arm 119. Each air cylinder 133 is charged with air under
pressure of such a magnitude that allows its piston rod 133a to be
fully extended and support the swingable arm 119 substantially
horizontally as shown in FIG. 26. After thus being charged with
air under pressure, the inlet port of the cylinder 133 is closed.
It is noted that the take-up reel 35 is supported at a
position shown in FIGS. 26 and 27 and it remains in that position
without moving vertically during veneer reeling operation.
As veneer reeling is initiated and veneer roll 66 grows
gradually to increase its diameter, the force with which the veneer
roll 66 presses against the belts 4 is increased and the belts and
the plates 130 are forced down gradually from the initial position
to reduce the spaced distance between the plates 130 and the
support plate 128. When the plates 130 are moved enough to strike
the limit switch 132 on the support plate 128, the control (not
shown) then responding to a signal from the limit switch 132
generates a command signal to open the outlet port of the cylinders
133 thereby to reduce the air pressure therein. The piston rod
133a is moved the cylinder 133 and the arms 119 are swung downward
together with the pulleys 122. Though the spaced distance between
the support plate 128 and the veneer roll 66 is increased, the
plates 130 urged upward by the cylinders 131 are not lowered with
- 36 -
CA 02247236 1998-09-11
1 the arms 119, so that the limit switches 132 are moved away from
the plates 130 and then clear thereof. The control then responding
to a signal from the limit switches 132 cleared of the plates 139
is operated to close the outlet port of the cylinders 133 and,
therefore, the movement of the piston rod 133a into the cylinder
133 is stopped. Accordingly, the arms 119 stop their downward
swinging and supported by the cylinders 133 at a position slightly
lowered.from the initial horizontal position.
Each time the veneer roll 66 becomes large enough to actuate
the limit switch 132, the above operation is repeated to lower the
arms 119 gradually. After a complete veneer roll 66 is formed and
removed from the apparatus, the cylinders 133 are recharged with
air under the above pressure for the next reeling operation.
(17) In the first and second embodiments, the touch rolls 6
are arranged to be freely rotatable and driven to rotate by
frictional force from the take-up reel 35 or veneer roll 66.
Depending on the species of veneer, the peripheral speed of veneer
roll 66 may be reduced relative to the conveying speed of the belts
4 because of resistance offered by the touch rolls 6, with the
result that a difference may occur between the feeding speed of
veneer sheet 65 moved by the belts 4 and the peripheral speed of
veneer roll 66. Such difference in speed may cause slack in the
veneer sheet upstream of the touch rolls 6, which in turn produces
harmful folds in the sheet.
To prevent the touch rolls 6 from being slowed down, it may
be so arranged that the rolls are positively driven by a motor so
that they are rotated in the same direction as the belts 4 and at a
peripheral speed that is slightly higher than the traveling speed
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CA 02247236 1998-09-11
1 of the belts 4.
(18) While veneer sheet is wound together with threads 30 in
the preceding embodiments, gum tapes may be used instead which are
fed from any appropriate position upstream of the take-up reel 35
and applied to the sheet to be wound therewith. The use of such
adhesive tapes can help to strengthen the veneer sheet.
While the invention has been described and illustrated with
reference to the specific embodiments, it is to be understood that
the present invention can be practiced in other various changes and
modifications without departing from the spirit or scope thereof.
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