TECHNICAL FIELD
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The present invention relates to a cut and removal apparatus
and a cut and removal method for forming a through hole
in a predetermined shape in a single-layer or multilayer sheet-like
member.
BACKGROUND ART
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As one of methods for forming through holes in a sheet-like
member, known is a method using a cutter roll called a die
cutter (see Japanese Laid-Open Patent Publication No. 8-71999
and No. 11-188698, for example). The cutter roll die-cuts a
sheet-like member in cooperation with an anvil roll. In this
prior art, however, no disclosure is made on how to dispose of
die-cut portions die-cut off from the sheet-like member. If
die-cut portions are not properly disposed of, a die of the
cutter roll and the like may be clogged with such die-cut portions,
and as a result, frequent cleaning of the cutter roll
may be necessary. This reduces the serviceability ratio of the
apparatus.
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Japanese Laid-Open Patent Publication No. 8-52696 discloses
an apparatus for producing sanitary goods by die-cutting
a whole cloth sheet. In this prior art, die-cut sanitary goods
are passed to a feed roll to be transported to a next process
stage.
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The feed roll that receives the sanitary goods by adsorption
rotates while keeping external contact with the cutter
roll. Therefore, the structure of the prior art is not suitable
for high-speed operation. Moreover, since the cutter roll
performs only sucking, suction holes thereof are easily
clogged. This reduces the serviceability ratio of the apparatus.
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In order to overcome the above problems, an object of the
present invention is to provide a cut and removal apparatus and
a cut and removal method capable of attaining a high serviceability
ratio and high-speed operation.
DISCLOSURE OF THE INVENTION
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To attain the object of the present invention, according
to one embodiment of the invention, the cut and removal apparatus
includes an anvil roll, a cutter roll, and a suction part.
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The cutter roll is placed in an almost-contact position
with respect to the anvil roll. The cutter roll has at least
one blade in a loop shape for die-cutting off a predetermined
portion from a sheet-like member. The cutter roll has an air
vent for supplying and discharging air in an inner-loop region
surrounded by the blade, and holds a die-cut portion obtained
by the die-cutting with the blade. The suction part is placed
at a position apart from the outer circumference of the cutter
roll for sucking the held die-cut portion.
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As used herein, the "almost-contact position" refers to
the position in which the anvil roll and the cutter roll are in
parallel with each other and are close to or in contact with
each other to such a degree that the blade of the cutter roll
can die-cut the sheet-like member in cooperation with the anvil
roll.
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According to one embodiment of the present invention, the
cut and removal method uses the cut and removal apparatus described
above. In this method, the cutter roll rotates while
the sheet-like member is being fed between the two rolls. The
method includes steps of decompression, die-cutting, transportation,
pressurization, and charging performed during one rotation
of the cutter roll.
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In the decompression step, a plurality of air vents in
the inner-loop region communicate with a negative pressure
chamber to reduce the atmospheric pressure near the surface of
the inner-loop region. In the die-cutting step, the blade is
in contact with the surface of the anvil roll so that the die-cut
portion is die-cut off from the sheet-like member with the
blade. In the transportation step, the die-cut portion is
transported along the circumference of the cutter roll while
being kept adsorbed to the surface of the inner-loop region.
In the pressurization step, the plurality of air vents in the
inner-loop region communicate with a positive pressure chamber
to raise the atmospheric pressure near the surface of the inner-loop
region. In the charging step, the die-cut portion in
the inner-loop region is sucked into the suction part and discharged.
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According to the present invention, air is supplied to
the air vents to which the die-cut portion is adsorbed. This
prevents the air vents from clogging, and therefore improves
the serviceability ratio of the apparatus.
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The die-cut portion held on the cutter roll is sucked
into and transported through the suction part located apart
from the surface of the cutter roll. This enables high-speed
operation of the apparatus.
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In the present invention, the die-cut portion sucked into
the suction part may be collected and discarded, or may be recycled.
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In the present invention, the shape of the through holes
formed by die-cutting the sheet-like member may be circular,
oval, or polygonal, or may be any combination of straight lines
and/or curved lines.
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The blade of the cutter roll is looped, which generally
exhibits higher strength than a non-looped blade.
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The thickness of the blade of the cutter roll is preferably
determined so that the area of the portion of the blade
coming into contact with the anvil roll is substantially constant
at any time. This makes it possible to keep constant the
pressure exerted when the blade of the cutter roll is brought
into contact with the anvil roll.
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The cutter roll and the anvil roll may be made of a material
such as tool steel, high-speed tool steel, powder high-speed
tool steel by HIP and sintering, and cemented carbide.
The hardness may be different between the cutter roll and the
anvil roll. For a longer life of the blade, the hardness of
the cutter roll is preferably greater than the hardness of the
anvil roll.
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The blade may be coated with diamond-like carbon.
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When two or more blades are provided, the blades may
preferably be placed at an equiangular pitch for nicely balanced
rotation of the cutter roll.
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In the discharging step, as the distance between the suction
inlet of the suction part and the blade is smaller, the
suction part can suck the die-cut portion stably. However, if
the distance is too small, the die-cut portion is easily caught
on the blade or easily twisted about near the suction inlet,
possibly damaging the suction part and the blade. Therefore,
in general, the distance is preferably set at 5 mm to 45 mm.
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One or more air vents are provided for one inner-loop region.
In general, a plurality of, or a number of air vents
having small open ends are preferably provided.
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In a preferred example of the present invention, the cut
and removal apparatus described above further includes a negative
pressure chamber turned to a negative pressure and a positive
pressure chamber turned to a positive pressure. The
plurality of air vents are placed to communicate with one of
the negative pressure chamber and the positive pressure chamber
alternately via at least one path depending on the phase of the
inner-loop region. The area of an open end of the path communicating
with the negative pressure chamber or the positive
pressure chamber is preferably equal to or greater than the sum
of the cross-sectional areas of the plurality of air vents.
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By setting the area as described above, the negative
pressure from the negative pressure chamber and the positive
pressure from the positive pressure chamber act effectively
near the surface of the inner-loop region.
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As used herein, the "phase" refers to the angle measured
from the reference point.
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In the present invention, the size of the die-cut portion
is not limited. However, in a preferred example of the present
invention, the area of the die-cut portion, that is, the area
of the inner-loop region is set in a range of about 10 cm2 to
about 70 cm2. If the area of the die-cut portion exceeds 70
cm2, the opening of the suction part must be made large. This
increases suction loss.
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In another preferred example of the present invention,
the suction part has a roughly circular opening for sucking the
die-cut portion, and the diameter of the opening is set at
roughly one to five times as large as the length of the blade
in the rotation direction of the cutter roll.
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If the opening of the suction part is excessively large
compared with the blade, the suction part may fail to suck the
die-cut portion, or suction loss increases.
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In yet another preferred example of the present invention,
the surface of the inner-loop region of the cutter roll
protrudes outwards in the radial direction of the cutter roll
from the surface of the portion of the cutter roll outside the
blade. In the inner-loop region, air between the die-cut portion
and the surface of the cutter roll is sucked. Therefore,
with the above structure in this preferred example, it is possible
to swiftly reduce the atmospheric pressure in the inner-loop
region, and also possible to easily feed the sheet-like
member between the cutter roll and the anvil roll.
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According to another embodiment of the present invention,
the cut and removal apparatus includes an anvil roll, a cutter
roll, a suction device, an air supply device, and a duct.
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The cutter roll is placed in an almost-contact position
with respect to the anvil roll. The cutter roll has a blade in
a loop shape for die-cutting off a predetermined portion. The
cutter roll has an air vent in an inner-loop region surrounded
by the blade. The suction device sucks air through the air
vent while the inner-loop region rotates over a first range of
predetermined phases to adsorb a die-cut portion obtained by
the die-cutting with the blade to the surface of the inner-loop
region. The air supply device supplies air between the surface
of the inner-loop region and the die-cut portion through the
air vent during rotation of the inner-loop region over a second
range of other predetermined phases. The duct sucks the die-cut
portion from outside the cutter roll to transport the die-cut
portion together with air during rotation of the inner-loop
region over the second range.
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In a preferred example of the present invention, the suction
device includes a first chamber communicating with the air
vent during the rotation over the first phase range. The air
supply device includes a second chamber communicating with the
air vent during the rotation over the second phase range. The
two chambers are formed in (defined by) a neighboring member
located near the cutter roll, and separated from each other to
prevent communication with each other.
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According to another embodiment of the present invention,
the cut and removal method uses the cut and removal apparatus
of the embodiment described above. This method includes steps
of decompression, die-cutting, transportation, pressurization,
and charging performed during one rotation of the cutter roll.
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In the decompression step, a plurality of air vents in
the inner-loop region communicate with the first chamber to reduce
the atmospheric pressure near the surface of the inner-loop
region. In the die-cutting step, the blade is in contact
with the surface of the anvil roll so that the die-cut portion
is die-cut off from the sheet-like member with the blade. In
the transportation step, the die-cut portion is transported
along the circumference of the cutter roll while being kept adsorbed
to the surface of the inner-loop region. In the pressurization
step, the plurality of air vents in the inner-loop
region communicate with the second chamber to raise the atmospheric
pressure near the surface of the inner-loop region. In
the charging step, the die-cut portion in the inner-loop region
is sucked into the duct together with air and discharged.
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As used herein, the "sheet-like member" refers to a
cloth-like structure having a large area compared with its
thickness, including fiber laminates and the like in addition
to films and cloths. It may be continuous in the form of a
roll such as a web, and as a concept, it includes semimanufactures
of sanitary napkins and disposable diapers and pants.
BRIEF DESCRIPTION OF THE DRAWINGS
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The present invention will be more clearly understood by
reading the following description of preferred examples in conjunction
with the accompanying drawings. It should be understood,
however, that the examples disclosed herein in
conjunction with the drawings are presented merely for illustration
and description of the invention and should not be used
for restricting the present invention. The present invention
is only restricted by the appended claims. In the accompanying
drawings, the same or like components are denoted by the same
reference numerals throughout the drawings.
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FIG. 1 is an exploded perspective view showing an outline
of a cut and removal apparatus of the first example of the present
invention. FIG. 2 is a side layout of the cut and removal
apparatus. FIG. 3 is a partially omitted vertical section of a
cutter roll. FIG. 4 is a layout of a cut and removal apparatus
of the second example. FIG. 5 is a plan view of an anvil roll.
BEST MODE FOR CARRYING OUT THE INVENTION
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Hereinafter, examples of the present invention will be
described with reference to the relevant drawings.
First example:
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FIGS. 1 to 3 illustrate the first example.
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Referring to FIG. 1, a continuous sheet-like member, that
is, a web 3 is fed between an anvil roll 1 and a cutter roll 2.
By the passing of the web 3 between the cutter roll 2 and the
anvil roll 1, predetermined portions (die-cut portions) 31 are
die-cut off from the web 3, forming through holes 30 in the web
3 at a predetermined pitch.
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The cutter roll 2 is in an almost-contact position with
respect to the anvil roll 1. The cutter roll 2 has a plurality
of blades 20, for example. The blades 20, each in a loop
shape, are used for die-cutting off the die-cut portions 31.
In this example, increased-diameter flange portions 23 of the
cutter roll 2 are in external contact with the anvil roll 1.
The flange portions 23 serve to stabilize the rotation of the
cutter roll 2 and protect the blades 20.
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First and second fixing members (neighboring members) 61
and 62 are provided on the two sides of the cuter roll 2, and
the fixing members 61 and 62 are secured to a frame not shown.
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A number of air vents 22 are formed in an inner-loop region
21 of each blade 20 of the cutter roll 2. As clearly
shown in FIG. 3, the air vents 22 extend in the radial direction
of the cutter roll 2 and open externally at the inner-loop
region 21, so that the die-cut portion 31 is adsorbed to and
held on the surface of the inner-loop region 21, as will be described
later.
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Referring to FIG. 1, the illustrated cut and removal apparatus
includes a suction device 4 and an air supply device 5.
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Inside the cutter roll 2, a plurality of communicating
paths 24 communicating with the air vents 22 extend in parallel
with each other in the axial direction. As shown in FIG. 3,
one end of each of the communicating paths 24 is closed by the
first fixing plate 61, while the other end thereof communicates
with a negative pressure chamber (first chamber) 41 or a positive
pressure chamber (second chamber) 51 formed inside the
second fixing plate 62.
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The negative pressure chamber 41 and the positive pressure
chamber 51 are separated from each other to prevent communication
with each other, while they communicate with a
pneumatic source 7 via piping members 42 and 52, and the like.
The pneumatic source 7, which includes a pump, a tank, an ejector,
and the like although they are not shown, sucks air inside
the negative pressure chamber 41 via the piping member 42 and
supplies pressure air into the positive pressure chamber 51 via
the piping member 52.
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Referring to FIG. 2, while the inner-loop region 21 rotates
over a first range 1 of predetermined phases, the air
vents 22 in this inner-loop region communicate with the negative
pressure chamber 41 via the communication path 24. The
suction device 4 shown in FIG. 1 sucks air through the air
vents 22 to allow the die-cut portion 31 cut off with the blade
20 to be adsorbed to the surface of the inner-loop region 21.
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Referring to FIG. 3, while the inner-loop region 21 rotates
over a second range 2 of other predetermined phases
(FIG. 2), the air vents 22 communicate with the positive pressure
chamber 51 via the communicating path 24. The air supply
device 5 supplies air under pressure out to a space between the
surface of the inner-loop region 21 and the die-cut portion 31
through the air vents 22.
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Referring to FIG. 2, a tapered hood 81 coupled to a duct
80 is placed in the vicinity of the cutter roll 2. The duct 80
communicates with a pneumatic source 82 for sucking air inside
the duct 80. The pneumatic source 7 may also serve as the
pneumatic source 82. The duct 80 and the hood 81 constitute a
suction part 8. During the rotation of the inner-loop region
21 over the second range 2, the suction part 8 sucks the die-cut
portion 31 from outside the cutter roll 2 into the duct 80
and transports it together with air.
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Next, the cut and removal method will be described.
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The cutter roll 2 rotates while the sheet-like member 3
is being fed between the two rolls 1 and 2. During one rotation
of the cutter roll 2, process steps of decompression, die-cutting,
transportation, pressurization, and discharging are
performed.
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Once the inner-loop region 21 reaches the first range 1
by the rotation of the cutter roll 2, the decompression step
starts, in which the plurality of air vents 22 in the inner-loop
region 21 come to communicate with the negative pressure
chamber 41 via the communicating path 24, to allow the pneumatic
source 7 to suck air through the air vents 22. As a result,
the atmospheric pressure near the surface of the inner-loop
region 21 gradually decreases.
As the inner-loop region 21 comes closer to the surface
of the anvil roll 1, the die-cutting step starts, in which the
blade 20 comes into contact with the surface of the anvil roll
1, to allow the die-cut portion 31 (FIG. 1) to be die-cut off
from the sheet-like member 3 in cooperation between the blade
20 and the anvil roll 1. The die-cut portion 31 is then adsorbed
to the surface of the inner-loop region 21.
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In the transportation step, the die-cut portion 31, that
is kept adsorbed to the surface of the inner-loop region 21, is
transported along the circumference of the cutter roll 2 with
the rotation of the anvil roll 1.
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When the inner-loop region 21 reaches the second range 2
as the cutter roll 2 continues rotating, the pressurizing step
starts, in which the plurality of air vents 22 in the inner-loop
region 21 communicate with the positive pressure chamber
51 via the communicating path 24, to allow the pneumatic source
7 to supply compressed air to the air vents 22 under pressure.
As a result, the atmospheric pressure near the surface of the
inner-loop region 21 increases.
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In the discharging step, with the increased atmospheric
pressure, the die-cut portion 31 adsorbed to the surface of the
inner-loop region 21 becomes easily detached from the surface
of the cutter roll 2. The die-cut portion 31 is therefore
sucked at a suction inlet 83 of the hood 81 into the duct 80
together with air and discharged.
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With continuous rotation of the cutter roll 2, the above
process steps are performed in sequence for the respective inner-loop
regions 21, forming the through holes 30 in the web 3
at a predetermined pitch by die-cutting. Note that the anvil
roll 1 is rotatable.
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In the cut and removal method described above, as shown
in FIG. 3, when the die-cut portion 31 is sucked into the duct
80, compressed air is jet from the air vents 22. This makes
the air vents 22 resistant to clogging and also prevents the
die-cut portion 31 from blocking the inner-loop region 21. In
addition, the die-cut portion 31 is sucked into the hood 81 of
which the opening is located apart from the cutter roll 2.
This enables high-speed operation of the apparatus.
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In this apparatus, it is preferable to set the area of
the open end 25 of each of the communicating paths 24 communicating
with the negative pressure chamber 41 or the positive
pressure chamber 51 and the cross-sectional area of the communicating
path 24 to be equal to or more than the sum of the
cross-sectional areas of the plurality of air vents 22 communicating
with the communicating path 24. Only one communicating
path 24, or a plurality of communicatinq paths 24 may communicate
with one inner-loop region 21. Note however that the
first and second ranges 1 and 2 shown in FIG. 2 should be
set so that one inner-loop region 21 is prevented from communicating
both the negative pressure chamber 41 and the positive
pressure chamber 51 simultaneously.
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The area of the die-cut portion 31, that is, the area of
the inner-loop region 21 is preferably set at 10 cm2 to 70 cm2.
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In this apparatus, the surface of the inner-loop region
21 preferably protrudes outwards in the radial direction of the
cutter roll 2 by a slight amount ΔH from the surface of the
portion of the cutter roll 2 outside the blade 20. This can
reduce the capacity of air existing between the die-cut portion
31 and the surface of the cutter roll 2 in the inner-loop region
21, and thus shorten the time required for decompression.
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Referring to FIG. 2, the diameter D of the suction inlet
83 of the hood 81 is preferably equal to or larger than the
length of the blade 20 in the rotation direction of the cutter
roll 2 and equal to or smaller than five times as large as the
length of the blade 20.
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A cover and door 100 covering the cutter roll 2 and the
like may be provided for prevention of entering of dirt and
dust.
Second example:
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FIGS. 4 and 5 illustrate the second example.
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As shown in FIG. 4, in the apparatus of this example,
through holes 30 may be formed for discontinuous sheet-like
members. In this case, as shown in FIG. 5, the anvil roll 1
includes a holding section 10 for holding the sheet-like member
3. The holding section 10 may be constructed of an arm or the
like for pressing the sheet-like member 3 against the surface
of the anvil roll 1. In general, however, the holding section
10 is preferably composed of a plurality of air vents 12 to
provide adsorption function with air as in the cutter roll 2
described above.
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In this case, it is necessary to establish a predetermined
positional relationship between the holding section 10
and the blade 20 and a predetermined phase relationship between
the anvil roll 1 and the cutter roll 2. As the means for feeding
and transporting the web 3, transfer drums 13 and 14 may be
used.
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The other construction in this example is substantially
the same as that in the first example, and therefore the same
or corresponding components are denoted by the same reference
numerals, and the detailed description thereof is omitted here.
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Thus, preferred embodiments were described with reference
to the relevant drawings. It is believed obvious to those
skilled in the art that changes and modifications of the present
invention are possible in light of the above teaching and
known techniques.
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For example, the plurality of blades are not necessarily
placed at an equiangular pitch. Only one blade 20 may be provided
on the cutter roll 2. The flange portions 23 may not be
provided. The pneumatic sources 7 and 82 may be united.
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Such changes and modifications are therefore construed to
fall within the scope of the present invention as defined by
the appended claims.
INDUSTRIAL APPLICABILITY
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The present invention is applicable to high-speed machine
for continuously forming through holes in a sheet-like member.
