Note: Descriptions are shown in the official language in which they were submitted.
CA 02309476 2000-OS-26
Band Steel Plate Winding Apparatus
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a band steel
plate winding apparatus for use in rolling equipment for
a hot rolled band steel plate or the like. More
particularly, the invention relates to a winding
apparatus for taking up a band steel plate with a
thickness of, for example, 1 . 6 mm or less at a high speed
of, for example, 800 m/min or more:
2. Description of the Related Art
A conventional band steel plate winding device
of this type is shown, for example, in FIG. 8. This
device is a winding device for a band steel plate,
generally called downcoiler. As shown in FIG. 8, a
plurality of roller tables 1 are disposed with
predetermined spacing on a rolling equipment line, and
a pinch roll (or a deflector roll) 2 is disposed near
a delivery side of each roller table 1. A band plate
3 of a steel product (hereinafter referred to as a band
steel plate) that has been rolled is guided to winding
drums (mandrels) 4 of a plurality of winders disposed
with predetermined spacing below the rolling equipment
line. Around each winding drum 4, a plurality of (3 in
the drawing) arm-shaped frames 5a, 5b and 5c are provided
1
- CA 02309476 2000-OS-26
which are each supported at one end on a fixing base 6
via a shaft 7. Each of these frames is pivotable such
that its front end is brought toward or away from the
winding drum 4 from three directions. On the frames 5a,
5b and 5c, unit rolls 8a, 8b and 8c are supported so as
to come into contact with the winding drum 4, and curved
surface guides 9a, 9b and 9c are attached downstream from
the unit rolls 8a, 8b and 8c. To these frames 5a, 5b
and 5c, driving cylinders 10a, lOb and lOc are connected
for driving the frames 5a, 5b and 5c so as to be brought
toward or away from a circumferential surface of the
winding drum 4.
Thus, the rolled band steel plate 3 is moved from
one of the pinch rolls 2 along a guide (not shown) , and
its front end is guided to one of the winding drums 4.
Then, the rolled band steel plate 3 is taken up into a
space defined by the winding drum 4, the three unit rolls
8a, 8b and 8c, and the three curved surface guides 9a,
9b and 9c. Further, the unit rolls 8a, 8b and 8c are
pressed against the winding drum 4 by the driving
cylinders 10a, lOb and 10c, whereby the band steel plate
3 begins to be wrapped round the winding drum 4 with an
adequate pressing force. After an adequate tension has
become obtainable by a frictional force between the band
steel plate 3 and the winding drum 4, wrapping of the
band steel plate 3 round the winding drum 4 is performed,
with the unit rolls 8a, 8b and 8c and the curved surface
2
- CA 02309476 2000-OS-26
guides 9a, 9b and 9c being separated (moved backward)
from the winding drum 4.
After a predetermined length of the band steel
plate 3 is taken up, the band steel plate 3 is cut with
a cutter (not shown) disposed on the rolling equipment
line . A front end of the remaining band steel plate 3
is guided from the other pinch roll 2 to the other winding
drum 4, and the band steel plate 3 is similarly wound.
During this period, a coil of the band steel plate 3 is
removed from the circumferential surface of the winding
drum 4, which has finished winding, onto a carrier
trolley or the like. In this manner, winding into a coil
is continued.
The conventional device shown in FIG. 8 has been
restricted in the speed of wrapping of the band steel
plate 3 round the winding drum 4. That is, when the
thickness of the band steel plate 3 is as small as 1.6
mm or less, and the rolling speed is fast, not only a
radially outward force due to the flexural rigidity of
the band steel plate 3 itself, but also the inertial
force of the band steel plate 3, i.e., a great
centrifugal force on the band steel plate 3 are exerted
generally at a wrapping speed of 800 m/min or more. As
a result, the band steel plate 3 is strongly pressed
against the curved surface guides 9a, 9b and 9c to
generate high frictional resistance in the direction in
which the band steel plate 3 advances. The resulting
3
CA 02309476 2000-OS-26
frictional force causes buckling to the band steel plate
3, whereby a front end portion of the band steel plate
3 is folded between the curved surface guides 9a, 9b,
9c and the winding drum 4. Consequently, even when the
winding drum 4 and the unit rolls 8a, 8b, 8c are
rotationally driven by an electric motor powerfully, it
is impossible to guide the band steel plate 3 around the
winding drum 4 and wrap it round the winding drum 4.
SUMMARY OF THE INVENTION
The present invention has been accomplished to
solve the above-described problems with the earlier
technology. It is an object of this invention to provide
a band steel plate winding apparatus which permits high
speed winding of a band steel plate while effectively
preventing buckling of a front end of the band steel
plate, and which can avoid a great increase in equipment
cost.
An aspect of the present invention, for attaining
the above obj ect, is a band steel plate winding apparatus
comprising:
a winding drum for taking up a band steel plate;
unit rolls, and curved surface guides adjacent
to the unit rolls, provided along a circumferential
surface of the winding drum forwardly and backwardly
movably between a winding drum surrounding position and
4
CA 02309476 2000-OS-26
a retreat position; and
ejection nozzles opened and formed in a guide
surface of each of the curved surface guides for ejecting
a gaseous or liquid fluid toward the band steel plate.
Thus, buckling stress of the band steel plate
caused by contact between the curved surface guide and
the band steel plate can be decreased, so that high speed
winding can be achieved, with buckling bending of the
band steel plate being prevented.
The band~steel plate winding apparatus may
further include:
a steel plate front end detector for detecting
a front end of the band steel plate traveling on a roller
table; and
a controller for computing fluid ej ection timing
based on a front end detection signal from the steel
plate front end detector and permitting the ejection
nozzles to eject the fluid with appropriate timing.
Thus, the amount of the fluid used can be
decreased.
The band steel plate winding apparatus may
further include:
a fluid receiver provided between the ejection
nozzles and a pressure generation source,
whereby a pressurized fluid necessary during
wrapping of the band steel plate round the winding drum
can be supplied from the fluid receiver, and supply of
CA 02309476 2000-OS-26
a pressure to the fluid receiver can be performed with
timing other than during wrapping of the band steel plate
round the winding drum.
Thus, a pressure generator of a great capacity
is not required, and an operation can be carried out
using an inexpensive device.
In the band steel plate winding apparatus,
a fluid supply pipe may extend over a nearly
entire width of an inside chamber of each of the curved
surface guides, and
the fluid supply pipe may have openings in the
inside chamber on a side opposite to the ejection nozzle
of the guide surface.
Thus, the fluid can be ej ected from the ej ection
nozzles nearly uniformly to wrap the band steel plate
smoothly round the winding drum without causing a
sideways movement of the band steel plate.
Another aspect of the invention is a band steel
plate winding apparatus comprising:
a winding drum for taking up a band steel plate
unit rolls, and curved surface guides adjacent
to the unit rolls, provided along a circumferential
surface of the winding drum forwardly and backwardly
movably between a winding drum surrounding position and
a retreat position,
a position of the unit roll relative to the
winding drum at a time of entry of the band steel plate
6
- CA 02309476 2000-OS-26
being downstream at an angle of about 15 degrees or less
from a position of contact between the winding drum and
the band steel plate; and
ejection means provided for ejecting,a gaseous
or liquid fluid at a high speed toward the band steel
plate from the curved surface guide before the band steel
plate collides with the curved surface guide.
Thus, the band steel plate is caused to collide
with the curved surface guide at a small angle of about
30 degrees or less . Because of this action coupled with
a fluid ejecting action, buckling stress of the band
steel plate caused by contact between the curved surface
guide and the band steel plate can be decreased, so that
high speed winding can be achieved, with buckling
bending of the band steel plate being prevented.
In the above band steel plate winding apparatus,
the fluid may be ejected in a direction of a center line
of the winding drum, or may be ejected with a slope in
a direction of advance of the band steel plate.
Thus, contact between the curved surface guide
and the band steel plate can be prevented effectively.
The band steel plate winding apparatus may
further include:
a steel plate front end detector for detecting
a front end of the band steel plate traveling on a roller
table; and
a controller for computing fluid ejection timing
7
~ CA 02309476 2000-OS-26
based on a front end detection signal from the steel
plate front end detector and permitting the ejection
means to eject the fluid with appropriate timing.
Thus, the amount of the fluid used can be
decreased.
The band steel plate winding apparatus may
further include:
a fluid receiver provided between the ejection
means and a pressure generation source,
whereby a pressurized fluid necessary during
wrapping of the band steel plate round the winding drum
can be supplied from the fluid receiver, and supply of
a pressure to the fluid receiver can be performed with
timing other than during wrapping of the band steel plate
round the winding drum.
Thus, a pressure generator of a great capacity
is not required, and an operation can be carried out
using an inexpensive device.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other objects, features and
advantages of the present invention will become more
apparent from the following description taken in
connection with the accompanying drawings, in which:
FIG. 1 is a side view of a band steel plate winding
apparatus (downcoiler) showing a first embodiment of the
8
CA 02309476 2000-OS-26
present invention;
FIG. 2 is an enlarged view of an essential part
of FIG. 1 showing the situation of start of winding;
FIG. 3 is an enlarged view of the essential part
of FIG. 1 showing the situation of winding immediately
before winding a turn of a band steel plate;
FIG. 4 is a concept view of a gas supply system
showing a second embodiment of the present invention;
FIG. 5 is a sectional view taken on line A-A of
FIG. 4;
FIG. 6 is a concept view of a device for detecting
timing of passage of a front end of the band steel plate;
FIG. 7 is a concept view of signal processing in
a controller; and
FIG. 8 is a schematic side view of a conventional
winding device.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
A band steel plate winding apparatus according
to the present invention will now be described in detail
by way of preferred embodiments with reference to the
accompanying drawings.
[First Embodiment]
[Constitution]
FIG. 1 is a side view of a winding apparatus
(downcoiler) showing a first embodiment of the invention.
9
CA 02309476 2003-O1-03
FIG. 2 is an enlarged view of an essential part of FIG.
1 showing the situation of start of winding. FIG. 3 is
an enlarged view of the essential part of FIG. 1 showing
the situation of winding immediately before winding a
turn of a band steel plate. The same members as in FIG.
8 will be assigned the same reference numerals, and
overlapping explanations will be omitted.
As shown in the drawing, a pair of guide plates
lla and llb are disposed between a pinch roll (or a
deflector roll) 2 disposed on a rolling equipment line
and a winding drum (mandrel) 4 of a winding apparatus
disposed below the rolling equipment line. Thus, a
rolled band steel plate 3 is guided to a site between
the winding drum 4 and a most upstream unit roll-8a, the
site where the band steel plate 3 will be passed.
The winding drum 4 is located at a nearly
tangential position relative to entry of the band steel
plate 3. The unit roll 8a is located at a position
which is offset from the starting point of contact
between the band steel plate 3 and the winding drum 4 in
a moving direction (to a downstream side).by an offset
amount 8 of about 15 degrees or less. The spacing
between the winding drum 4 and the unit roll 8a ranges
from 0.3 to 5 mm added to the thickness of the band
steel plate 3. The peripheral velocity Vd of the unit
roll 8a, like the peripheral velocity Vm of the winding
drum 4, is not less than the entry velocity Vo of the
band steel plate 3. The peripheral velocity ratio
between them, Vd/Vo, is preferably about 1.1.
to
CA 02309476 2000-OS-26
A curved surface guide 12a, paired with the unit
roll 8a and supported on an arm-shaped frame 5a, is
shaped like a box. The interior of the curved surface
guide 12a is a gas (air) chamber 13, which is supplied
and charged with a pressurized gas (air) through a gas
(air) supply port (pipe) 14 from a pressurized gas (air)
supply source (not shown). In a guide surface of the
curved surface guide 12a, a plurality of ejection
nozzles 15 for the pressurized gas are opened and formed.
The position of the ejection nozzles 15a in the foremost
row (on the most upstream side) is not restricted, but
is preferably such that the ej ected pressurized gas will
strike the band steel plate 3 before the band steel plate
3 collides with the curved surface guide 12a. The
ejection angle of the ejection nozzles 15a in the
foremost row is not restricted, but is preferably such
that when only a row of the ejection nozzles 15a is
provided, these ejection nozzles 15a are directed toward
the center of the winding drum 4, or are inclined from
the center of the winding drum 4 in the advancing
direction of the band steel plate 3. For the other
ej ection nozzles 15b, the direction of ej ection of the
pressurized gas is not restricted. The ejection
pressure of the pressurized gas in the gas chamber 13
may be 0.2 atmosphere or more as gage pressure, and need
not be a particularly high pressure. The diameter of
the ejection nozzle 15a is 1 mm to 20 mm. The rate of
11
- CA 02309476 2000-OS-26
the hole area of the ejection nozzles is 10$ or less.
The spacing between the curved surface guide 12a
and the winding drum 4 is from 0.3 mm to 10 mm added to
the thickness of the band steel plate 3.
The curved surface guide 12a is provided apart
from a succeeding unit roll 8b such that the front end
of the curved surface guide 12a will be out of contact
with the unit roll 8b. The unit roll 8b also rotates
at a peripheral velocity greater than the entry velocity
of the band steel plate 3. A curved surface guide 12b
following the unit roll 8b is also constituted like the
curved surface guide 12a., In a subsequent stage as well,
a unit roll 8c and a curved surface guide 12c are
constituted in the same manner as described above.
Immediately before the front end of the band steel
plate 3 makes a turn about the winding drum 4, the guide
plate lla and the most downstream curved surface guide
12c become close to each other. The spacing between the
guide plate lla and the winding drum 4 is made at least
the same as the spacing between the curved surface guide
12c and the winding drum 4 so that the front end of the
band steel plate 3 will be able to pass through the gap
between the guide plate lla and the winding drum 4 and
collide with a succeeding band steel plate 3
(immediately before being wound). The arrangement of
the winding drum 4 and the trailing end of the curved
surface guide 12c has been determined so that the angle
12
CA 02309476 2000-OS-26
Ae of collision will be 45 degrees or less. The front
end of the band steel plate 3 that has collided with the
succeeding band steel plate 3 is to enter between the
band steel plate 3 and the winding drum 4 in a manner
linked to the movement of the band steel plate 3.
[Actions]
The band steel plate 3 fed out of the pinch roll
2 on the delivery side of the rolling equipment line is
fed around an empty winding drum 4 under guidance of the
guide plates 11a, 11b. The band steel plate 3 collides
with the unit roll 8a rotating at a peripheral velocity
greater than the entry velocity of the band steel plate
3. As a result, the band steel plate 3 changes its course
to be directed toward the winding drum 4, and points
toward the curved surface guide 12a. Then, the band
steel plate 3 collides with the curved surface guide 12a
at a small collision angle 8b of 30 degrees or less. This
is because the unit roll 8a is positioned at a site offset
in the advancing direction (toward a downstream side)
from the winding drum 4 by an offset amount 8 of within
15 degrees. It has been experimentally confirmed that
the collision angle 8b of 30 degrees or less does not
impede high speed winding of a thin band steel plate 3.
The band steel plate 3 that has collided with the
curved surface guide 12a immediately bounces back under
the pressure of the ejected pressurized gas and the
reaction force of the band steel plate itself, and
13
' CA 02309476 2000-OS-26
advances along the curved surface guide 12a. At this
stage, the band steel plate 3 undergoes a force, with
which to stick to the curved surface guide 12a, owing
to the reaction force associated with the centrifugal
force of the band steel plate 3 itself and its flexural
rigidity. However, its contact with the curved surface
guide 12a is inhibited by the pressure of the pressurized
gas from the ejection nozzles 15a, 15b in the curved
surface guide. Even if its contact occurred, its
frictional force is so small that the band steel plate
3 smoothly enters between the winding drum 4 and the
curved surface guide 12a without undergoing buckling.
On this occasion, the gap between the winding drum 4 and
the curved surface guide 12a may be relatively wide, and
may measure about 0.5 mm to 20 mm. Since the winding
drum 4 and the unit roll 8a rotate at the peripheral
velocities Vm and Vd greater than the entry velocity of
the band steel plate 3, they exert little force for
hindering entry of the band steel plate 3. A gas flow
between the winding drum 4 and the curved surface guide
12a preferably has a velocity not less than the velocity
of the band steel plate 3.
The band steel plate 3 having the front end past
the curved surface guide 12a collides with the unit roll
8b. Since the unit roll 8b also rotates at a peripheral
velocity greater than the entry velocity of the band
steel plate 3, it generates no force for pushing back
14
CA 02309476 2000-OS-26
the front end of the band steel plate 3, and allows the
band steel plate 3 to approach the curved surface guide
12b. The curved surface guide 12b, like the curved
surface guide 12a, has ejection nozzles 15a, 15b. Thus,
the band steel plate 3 having collided with the curved
surface guide 12b enters between the winding drum 4 and
the curved surface guide 12b without undergoing buckling
bending of its front end. At a subsequent stage, too,
the band steel plate 3 enters between the winding drum
4 and the unit roll 8c and between the winding drum 4
and the curved surface guide 12c.
Immediately before the front end of the band steel
plate 3 makes a turn about the winding drum 4, the guide
plate lla and the most downstream curved surface guide
12c become close to each other. It is advisable to make
the spacing between the guide plate lla and the winding
drum 4 at least the same as the spacing between the curved
surface guide 12c and the winding drum 4. In this case,
the front end of the band steel plate 3 will be able to
pass through the gap between the guide plate lla and the
winding drum 4 and collide with a succeeding band steel
plate 3 (immediately before being wound) . Experiments
have shown that the angle 8e of collision at this time
should be set at 45 degrees or less . Given this angle
of collision, the front end of the band steel plate 3
enters between the band steel plate 3 and the winding
drum 4 in a manner linked to the movement of the band
- CA 02309476 2000-OS-26
steel plate 3, without undergoing buckling.
The front end of the band steel plate 3 taken up
between the band steel plate 3 and the winding drum 4
moves in a manner linked to the movement of the winding
drum 4 rotating at a peripheral velocity greater than
the entry velocity of the band steel plate 3. Then, the
band steel plate 3 presses the unit rolls 8a, 8b, 8c,
whereby a pressing force is exerted on the band steel
plate 3. In this manner, the band steel plate 3 is
pressed against the winding drum 4, and two to five turns
of the band steel plate 3 are wound round the winding
drum 4. Normally, the winding drum 4 rotates at a
peripheral velocity greater than the peripheral
velocity of the band steel plate 3. Thus, a tightening
force during winding acts on the band steel plate 3,
causing tension to the band steel plate 3. Thereafter,
winding proceeds, with the tension of the band steel
plate 3 under control.
In the foregoing apparatus, the number of the
ej ection nozzles is large per winder, thus requiring a
large amount of air. Consequently, a high capacity
pressure generator (e.g., compressors becomesnecessary,
inducing a cost increase . A gas supply device proposed
as a countermeasure will be described in a second
embodiment of the invention.
[Second Embodiment]
[Constitution]
16
CA 02309476 2000-OS-26
FIG. 4 is a concept view of a gas supply system
showing the second embodiment of the invention. FIG.
is a sectional view taken on line A-A of FIG. 4. FIG.
6 is a concept view of a device for detecting timing of
passage of a front end of a band steel plate. FIG. 7
is a concept view of signal processing in a controller.
As illustrated, a steel plate front end detector
24 provided at a predetermined position detects that the
front end of a band steel plate 3, which was rolled by
a rolling roll 30, has traveled on a roller table 1 and
come to the predetermined position. A detection signal
from the steel plate front end detector 24 is entered
into a controller (computing unit) 25. The controller
25 computes timing with which to open a gas ejection
valve 21 interposed in a piping 20, from the velocity
of the steel plate and the distance from the steel plate
front end detector 24 to a winding drum 4. Using the
results of computation, the controller 25 sends an
"Open" signal to the gas ej ection valve 21 via a signal
cable 26. The controller 25 also computes a net ejection
time, and issues a "Close" signal to the gas ejection
valve 21. The piping 20 ties a gas chamber 13 of each
of curved surface guides 12a, 12b and 12c to a gas
receiver (accumulator) 22.
Then, with the gas ej ection valve 21 being closed,
a valve 23 is opened to supply a pressurized gas from
a pressure generator (e.g., compressor; not shown) into
17
CA 02309476 2000-OS-26
the gas receiver 22, making preparations for initiation
of subsequent winding. The capacity of the gas receiver
22 can be determined by the amount of ej ection and the
duration of ejection.
The pressurized gas supplied by the piping 20 is
guided into a gas supply port (pipe) 14 provided nearly
throughout the width of a gas chamber 13, and is admitted
into the gas chamber 13. If the sectional area of a
plurality of ejection ports 14a to 14g is made smaller
than the sectional area of the gas supply port (pipe)
14, the pressurized gas is emitted from the ejection
ports 14a to 14g nearly uniformly, making the pressure
distribution inside the gas chamber 13 nearly constant.
Taking an example, the transport speed of the band
steel plate 3 was set at 800 m/min, the distance traveled
by the band steel plate 3 from the steel plate front end
detector 24 to the winding drum 4 was set at 8 m, the
diameter of the piping 20 was set at 120 mm, and seven
ej ection ports 14a to 14g were provided in the gas supply
port (pipe) 14, with the diameter of each ejection port
being set at 20 mm. The length from the gas ejection
valve 21 to the gas chamber 13 with a capacity of 0.15
m3 was set at 5 m, the capacity of the gas receiver 22
at 1 m3, and the accumulated pressure at 3 atmospheres.
Twenty ejection nozzles 15 were provided in the gas
chamber 13, with the diameter of each ejection nozzle
being set at 10 mm.
18
CA 02309476 2000-OS-26
[Actions]
The distance from the curved surface guides 12a,
12b, 12c to the gas receiver 22 is short. Thus, the
pressurized gas can be ejected during the period from
detection of the approach of the band steel plate 3 and
issue of a gas ej ection signal until arrival of the band
steel plate 3 at the winding drum 4. When the distance
traveled by the band steel plate 3 from the steel plate
front end detector 24 to the winding drum 4 is 8 m, and
the transport speed of the band steel plate 3 is 800 m/min,
it takes 0.6 second for the band steel plate 3 to move
from the steel plate front end detector 24 to the winding
drum 4. This period of time is sufficient to cover the
period from start of control until start of ejection from
the ejection nozzles 15.
The duration of ejection of the pressurized gas
is equal to a period of time required for winding several
turns of the band steel plate 3 round the winding drum
4 . This period is calculated as follows : Assume that
the line velocity V is 800 m/min (= 13.3 m/sec) , and the
diameter d of the winding drum 4 is 765 mm. The winding
time z (sec) is indicated by the following equation, and
shown to be 0.18 sec per turn of the band steel plate
3 wound round the winding drum 4:
t = ~tdn/V = 0.18 to 0.9 (sec) where n denotes the
number of turns =~1 to 5.
Thus, the net required gas ejection time of 1.0
19
CA 02309476 2000-OS-26
to 2.0 seconds is enough, and if the gas is ejected only
with required timing, the amount of the gas used need
not be very large.
Even when the gas ej ection time is short, a high
capacity pressure generator is required, if the gas is
directly supplied from the gas generation source. In
the presence of a small capacity pressure generator (not
shown) and the gas receiver 22, a large amount of the
gas can be accumulated in the gas receiver 22 during a
gas supply interruption period. Thus, a pressure
generator of a large capacity is not required, and an
operation can be carried out using an inexpensive
device.
The gas may be ej ected with truly necessary timing
ensuring an ejection time of about 1 to 2 seconds, the
period of time over which several turns of the band steel
plate 3 are wound round the winding drum 4. Thus, the
amount of the gas used is limited. To eject this amount
at a time, a large capacity pressure generator is
necessary. However, if the gas receiver 22 is provided,
it is sufficient to accumulate air in the gas receiver
22 during a gas-unrequired period, a period during which
no gas is required for winding, while the band steel
plate 3 is being wound. Hence, an inexpensive pressure
generator of a small capacity suffices.
When the gas supplied from the gas receiver 22
is fed to the gas chamber 13, the gas is released nearly
CA 02309476 2000-OS-26
uniformly through the plurality of ejection ports 14a
to 14g in a direction opposite to the ejection nozzles
15 provided in the gas chamber 13. Since the gas chamber
13 is minimized in capacity, the pressure inside it
increases rapidly. The adequate pressure of the gas
chamber 13 is about 0.05 kgf/cmz as gage pressure. By
adjusting the opening of the valve or the flow rate of
the gas, therefore, an abrupt change in the gas pressure
can be prevented. The ejection ports 14a to 14g for the
gas are provided in the direction opposite to the
ej ection nozzles 15 provided in the gas chamber 13. Thus,
the gas can be released,nearly uniformly through the
ej ection nozzles 15, so that an uneven pressure is not
exerted on the band steel plate 3. Hence, the band steel
plate 3 is wrapped round the winding drum 4 without
undergoing a sideways movement.
In the present embodiment, the gas support port
(pipe) 14 has been shown to be provided with the ej ection
ports 14a to 14g. The hole diameter of the ejection
ports 14a to 14g may be progressively increased such that
greater hole diameters are given to the ej ection ports
located more downstream. Alternatively, the sectional
shape of the gas supply port (pipe) 14 may be made
semicircular, with openings being provided in the
semicircular gas supply port (pipe) 14 on a side opposite
to the ejection nozzles 15.
In the above-described embodiments, the three
21
CA 02309476 2000-OS-26
unit rolls and the three curved surface guides have been
provided, but four or more of the unit rolls and four
or more of the curved surface guides may be provided.
The invention being thus described, it will be
obvious that the same may be varied in many ways . Such
variations are not to be regarded as a departure from
the spirit and scope of the invention, and all such
modifications as would be obvious to one skilled in the
art are intended to be included within the scope of the
following claims.
22
