U.S. patent application number 14/893596 was filed with the patent office on 2016-05-05 for anvil roller and ultrasonic welding device provided therewith.
This patent application is currently assigned to ZUIKO CORPORATION. The applicant listed for this patent is ZUIKO CORPORATION. Invention is credited to Yukihiko Fujita, Hideyuki Nakamura.
Application Number | 20160121542 14/893596 |
Document ID | / |
Family ID | 52022388 |
Filed Date | 2016-05-05 |
United States Patent
Application |
20160121542 |
Kind Code |
A1 |
Fujita; Yukihiko ; et
al. |
May 5, 2016 |
ANVIL ROLLER AND ULTRASONIC WELDING DEVICE PROVIDED THEREWITH
Abstract
Provided is a lightweight anvil roller and an ultrasonic welding
device provided therewith. The anvil roller has: a supported
section that is rotatably supported by a holding mechanism via a
rotary shaft in such a manner that the anvil roller can come into
rolling contact with a sheet; an outer peripheral section having a
welding surface over which the sheet is welded between the outer
peripheral section and an ultrasonic horn during rolling contact
with the sheet; a thin section that is formed between the supported
section and the outer peripheral section in such a manner that the
thickness of the thin section is smaller than the thickness of the
outer peripheral section in the axial direction of the rotary
shaft; and a vibrationproof member provided on the thin
section.
Inventors: |
Fujita; Yukihiko; (Osaka,
JP) ; Nakamura; Hideyuki; (Osaka, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ZUIKO CORPORATION |
Settsu-shi, Osaka |
|
JP |
|
|
Assignee: |
ZUIKO CORPORATION
Settsu-shi, Osaka
JP
|
Family ID: |
52022388 |
Appl. No.: |
14/893596 |
Filed: |
June 13, 2014 |
PCT Filed: |
June 13, 2014 |
PCT NO: |
PCT/JP2014/065807 |
371 Date: |
November 24, 2015 |
Current U.S.
Class: |
156/580.2 |
Current CPC
Class: |
B29C 66/71 20130101;
B29C 65/086 20130101; B29C 66/71 20130101; B29C 66/0326 20130101;
B29C 66/8362 20130101; B29C 66/81431 20130101; B29L 2031/4878
20130101; A61F 13/15804 20130101; B29C 65/7885 20130101; B29C
66/232 20130101; B29C 66/433 20130101; B29C 66/81465 20130101; A61F
13/15699 20130101; A61F 13/15739 20130101; B29C 66/7294 20130101;
B29C 66/82263 20130101; B29C 66/83511 20130101; B29C 66/72343
20130101; B29K 2023/12 20130101; B29C 66/1122 20130101; B29C 66/431
20130101; B29C 65/087 20130101; B29C 65/7894 20130101; B29C
66/81427 20130101; B29K 2023/06 20130101; B29C 66/71 20130101 |
International
Class: |
B29C 65/08 20060101
B29C065/08 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 14, 2013 |
JP |
2013-125942 |
Claims
1. An anvil roller, used in an ultrasonic welding device that
includes: a holding member that holds an object to be welded; an
ultrasonic horn that applies ultrasonic vibration to the object to
be welded held by the holding member; an anvil roller for welding
the object to be welded between the ultrasonic horn and the anvil
roller; and a support mechanism that supports the anvil roller via
a rotary shaft in such a manner that the anvil roller can move with
respect to the holding member, and that the anvil roller can come
into rolling contact with the object to be welded in response to
the movement of the anvil roller with respect to the holding
member, the anvil roller comprising: a supported section that is
rotatably supported by the holding mechanism via the rotary shaft;
an outer peripheral section having a welding surface over which the
object to be welded can be welded between the ultrasonic horn and
the outer peripheral section during rolling contact with the object
to be welded; a thin section that is formed between the supported
section and the outer peripheral section in such a manner that the
thickness of the thin section is smaller than the thickness of the
outer peripheral section in an axial direction of the rotary shaft;
and a vibrationproof member provided on the thin section.
2. The anvil roller according to claim 1, wherein the
vibrationproof member is provided on a reverse face, with respect
to the welding surface, of the outer peripheral section, as defined
by the thin section.
3. The anvil roller according to claim 2, wherein the thin section
is provided over the entire circumference about the rotary shaft,
and the vibrationproof member is provided over the entire
circumference of the reverse face about the rotary shaft.
4. The anvil roller according to claim 2, wherein the
vibrationproof member is provided only over part of the thin
section.
5. The anvil roller according to claim 1 wherein the thickness of
the supported section is greater than the thickness of the thin
section in the axial direction of the rotary shaft.
6. The anvil roller according to claim 5, wherein the thickness of
the supported section is smaller than the thickness of the outer
peripheral section.
7. An ultrasonic welding device, comprising: a holding member that
holds an object to be welded; an ultrasonic horn that applies
ultrasonic vibration to the object to be welded held by the holding
member; the anvil roller according to claim 1, for welding the
object to be welded, between the ultrasonic horn and the anvil
roller; and a support mechanism that supports the anvil roller via
a rotary shaft in such a manner that the anvil roller can move with
respect to the holding member, and that the anvil roller can come
into rolling contact with the object to be welded in response to
the movement of the anvil roller with respect to the holding
member.
Description
TECHNICAL FIELD
[0001] The present invention relates to an anvil roller that is
used for ultrasonically welding an object to be welded, and to an
ultrasonic welding device that is provided with the anvil
roller.
BACKGROUND ART
[0002] Conventional ultrasonic welding devices include ultrasonic
welding devices each provided with an anvil and an ultrasonic horn,
wherein an object to be welded is sandwiched between the anvil and
the ultrasonic horn, and in that state, ultrasonic vibration is
applied to the ultrasonic horn, to weld as a result the object to
be welded.
[0003] Known ultrasonic welding devices of that type include
ultrasonic welding devices each provided with a holding member that
holds an object to be welded, and an anvil roller that can move
with respect to a holding member, between a welding position at
which the object to be welded, held on the holding member, is
welded between the ultrasonic horn and the anvil roller, and a
separation position that is spaced apart from the object to be
welded (for instance, Japanese Patent No 3988835).
[0004] The anvil roller disclosed in Japanese Patent No 3988835 is
rotatably supported about a predetermined rotation axis so that the
anvil roller can come into rolling contact with the object to be
welded, during the movement of the anvil roller.
[0005] A demand exists for a lighter anvil roller, in order to
reduce the load and power that is imparted to a support mechanism,
in a case where the anvil roller is supported movably with respect
to the object to be welded, as in the ultrasonic welding device
disclosed in Japanese Patent No 3988835.
SUMMARY OF INVENTION
[0006] It is an object of the present invention to provide a
lightweight anvil roller, and an ultrasonic welding device that is
provided therewith.
[0007] The present invention provides an anvil roller, used in an
ultrasonic welding device that includes: a holding member that
holds an object to be welded; an ultrasonic horn that applies
ultrasonic vibration to the object to be welded held by the holding
member; an anvil roller for welding the object to be welded,
between the ultrasonic horn and the anvil roller; and a support
mechanism that supports the anvil roller via a rotary shaft in such
a manner that the anvil roller can move with respect to the holding
member, and that the anvil roller can come into rolling contact
with the object to be welded in response to the movement of the
anvil roller with respect to the holding member, the anvil roller
including: a supported section that is rotatably supported by the
holding mechanism via the rotary shaft; an outer peripheral section
having a welding surface over which the object to be welded can be
welded between the ultrasonic horn and the outer peripheral section
during rolling contact with the object to be welded; a thin section
that is formed between the supported section and the outer
peripheral section in such a manner that the thickness of the thin
section is smaller than the thickness of the outer peripheral
section in an axial direction of the rotary shaft; and a
vibrationproof member provided on the thin section.
[0008] The present invention further provides an ultrasonic welding
device that is provided with: a holding member that holds an object
to be welded; an ultrasonic horn that applies ultrasonic vibration
to the object to be welded held by the holding member; the anvil
roller for welding the object to be welded, between the ultrasonic
horn and the anvil roller; and a support mechanism that supports
the anvil roller via a rotary shaft in such a manner that the anvil
roller can move with respect to the holding member, and that the
anvil roller can come into rolling contact with the object to be
welded in response to the movement of the anvil roller with respect
to the holding member.
[0009] The present invention allows reducing the weight of an anvil
roller.
BRIEF DESCRIPTION OF DRAWINGS
[0010] FIG. 1 is a process diagram for explaining a method of
producing a disposable diaper using an ultrasonic welding device
according to the present invention;
[0011] FIG. 2 is a front-view diagram illustrating the schematic
configuration of an ultrasonic welding device according to a first
embodiment of the present invention, for carrying out the welding
step illustrated in FIG. 1;
[0012] FIG. 3 is a cross-sectional diagram of FIG. 2 along line
III-III;
[0013] FIG. 4 is a cross-sectional diagram of FIG. 3 along line
IV-IV;
[0014] FIG. 5 is a front-view cross-sectional diagram of an anvil
roller illustrated in FIG. 4; and
[0015] FIG. 6 is a diagram, corresponding to FIG. 5, illustrating
an anvil roller of an ultrasonic welding device according to a
second embodiment of the present invention.
DESCRIPTION OF EMBODIMENTS
[0016] The embodiments of the present invention are described
hereinbelow by referring to the attached figures. The following
embodiments are examples substantiating the present invention and
do not limit the technical scope of the present invention.
[0017] With reference to FIG. 1, a disposable diaper 20 includes,
when worn, a front abdominal section 20a disposed on the abdomen of
the wearer, a rear dorsal section 20b disposed on the buttocks of
the wearer, and a crotch section 20c that extends from the front
abdominal section 20a, passing between the legs of the wearer, up
to the rear dorsal section 20b.
[0018] Both side edge portions of the front abdominal section 20a
and both side edge portions of the rear dorsal section 20b are
welded to each other by two weld sections S, in such a manner that
the front abdominal section 20a and the rear dorsal section 20b are
connected in the form of a ring.
[0019] A method of producing the disposable diaper 20 will be
explained next.
[0020] <Transport Step P1>
[0021] In the transport step P1, a sheet W that extends in a
specific direction is transported along the length direction of the
sheet W. In the explanation hereafter, the flow direction of the
sheet W will be referred to as transversal direction, and the
direction perpendicular to the transversal direction in FIG. 1 will
be referred to as longitudinal direction.
[0022] The sheet W has an inner sheet that faces the body surface
of the wearer when the wearer wears the diaper, an outer sheet that
faces away from the wearer when the wearer wears the diaper, and an
elastic member that is sandwiched between the inner sheet and the
outer sheet.
[0023] The inner sheet is constituted by a nonwoven fabric sheet
and/or a mesh sheet having liquid permeability. The outer sheet is
constituted by a material, identical to that of the inner sheet, a
polyethylene film, a polypropylene film, or a nonwoven fabric
having water repellency and breathability.
[0024] The elastic member is constituted by a sheet or thread made
of polyurethane, natural rubber, or a thermoplastic resin.
[0025] <Leg Hole Forming step P2>
[0026] In the leg hole forming step P2, leg holes L are formed at a
central position of the sheet W in the longitudinal direction.
[0027] Each region between the two leg holes L in the sheet W is a
portion corresponding to the crotch section 20c. The positions on
both sides of each portion in the sheet W corresponding to the
crotch section 20c, in the longitudinal direction, correspond
herein to the front abdominal section 20a and the rear dorsal
section 20b, respectively.
[0028] <Absorbent Body Bonding Step P3>
[0029] In the absorbent body bonding step P3, an absorbent body A
is bonded at a position in the sheet W between the two leg holes
L.
[0030] The absorbent body A includes a permeable sheet having
liquid permeability, a water-repellent sheet having
water-repellency and breathability, and an absorbent core
sandwiched between the permeable sheet and the water-repellent
sheet.
[0031] The permeable sheet is constituted by a nonwoven fabric
sheet and/or a mesh sheet having liquid permeability. The
water-repellent sheet is constituted by a polyethylene film, a
polypropylene film, or a nonwoven fabric having water-repellency
and breathability.
[0032] The absorbent core is molded through layering of crushed
pulp or crushed pulp mixed with a high water-absorbing polymer.
[0033] A method is explained herein where the absorbent body A is
bonded to the sheet W, but the absorbent core may be bonded in a
state where the absorbent core is sandwiched between the inner
sheet and the outer sheet of the sheet W. In this case, the inner
sheet is constituted by a nonwoven fabric sheet and/or a mesh sheet
having liquid permeability. The outer sheet is constituted by a
polyethylene film, a polypropylene film, or a nonwoven fabric
having water-repellency and breathability.
[0034] <Fold-in-Half Step P4>
[0035] In the fold-in-half step P4, the sheet W (continuous body)
having the absorbent body A placed thereon is folded in half in the
longitudinal direction. As a result, the portion of the sheet W
corresponding to the front abdominal section 20a and the portion
corresponding to the rear dorsal section 20b are overlapped on each
other.
[0036] <Welding step P5>
[0037] In the welding step P5, a portion of the folded sheet W
corresponding to a side edge portion of the front abdominal section
20a and the portion corresponding to a side edge portion of the
rear dorsal section 20b are ultrasonically welded.
[0038] In the welding step P5, specifically, two sites of the sheet
W are ultrasonically welded simultaneously, with a spacing D2
including a predetermined cutting range as a range of cutting in
the cutting step P6 described below.
[0039] The two weld sections S are respectively formed over a
welding range D1 in the longitudinal direction of a portion
corresponding to a side edge portion of the front abdominal section
20a, and a portion corresponding to a side edge portion of the rear
dorsal section 20b.
[0040] <Cutting Step P6>
[0041] In the cutting step P6, the sheet W is cut along a
respective cutting line that extends, in the longitudinal
direction, between two weld sections S formed in the welding step
P5. The sheet W (continuous body) is cut as a result into each
disposable diaper 20.
[0042] An explanation follows next, with reference to FIG. 2, on an
ultrasonic welding device 1, according to the first embodiment,
that carries out the welding step P5.
[0043] The ultrasonic welding device 1 is provided with an
introduction roller 2 that introduces the folded sheet W undergone
the fold-in-half step P4; a welding drum 3 that welds the sheet W
that is introduced by the introduction roller 2; and a lead-out
roller 4 that leads out the sheet W welded by the welding drum
3.
[0044] The welding drum 3 is provided with: a sheet holding drum
(holding member) 5 that holds the sheet (object to be welded) W
that is introduced by the introduction roller 2; six ultrasonic
horns 6 that are provided on the sheet holding drum 5; six anvil
units 7 for ultrasonically welding the sheet W between the
ultrasonic horns 6 and respective anvil units 7; a cylindrical
anvil holding drum 8 (see FIG. 3) that holds the anvil units 7; and
a cam drum 9 (see FIG. 3) provided inside the anvil holding drum
8.
[0045] With reference to FIG. 2 and FIG. 3, the sheet holding drum
5 can rotate about a rotation center C1 in a state where the sheet
W is held on the outer peripheral surface of the sheet holding drum
5. Six recessed grooves 5a are formed equidistantly, about the
rotation center C1, on the sheet holding drum 5. The recessed
grooves 5a open outward from the sheet holding drum 5 and extend
along the rotation center C1.
[0046] The ultrasonic horns 6 impart ultrasonic vibration to the
sheet W that is held on the sheet holding drum 5. Specifically, the
ultrasonic horns 6 are provided in respective recessed grooves 5a,
in such a manner that welding surfaces 6a of the ultrasonic horns 6
come in contact, from inside, with the sheet W that is held on the
sheet holding drum 5.
[0047] Each of the anvil units 7 is provided at position identical
to each of the ultrasonic horns 6, about the rotation center C1.
The anvil units 7 have all the same configuration; hence, the
configuration of just one of anvil unit 7 will be explained, and a
explanation of the other anvil units 7 will be omitted.
[0048] Anvil unit 7 is provided with an anvil roller 10 for welding
the sheet W between the ultrasonic horn 6 and the anvil roller 10,
and a holding mechanism 11 that holds rotatably the anvil roller
10, via a rotary shaft 12a, in such a manner that the anvil roller
10 can be in rolling contact with the sheet W, in response to the
displacement of the anvil roller 10 with respect to the sheet
holding drum 5.
[0049] As illustrated in FIG. 3 and FIG. 4, holding mechanism 11 is
provided with: a body section 12 that holds the anvil roller 10; a
cam protrusion 14 that extends from the body section 12 toward the
rotation center C1; and a pair of engaging protrusions 15 that
protrude from the body section 12, in opposite orientations in a
direction (left-right direction in FIG. 4) perpendicular to the cam
protrusion 14 and the rotation center C1, and that extend along the
rotation center C1.
[0050] The body section 12 is provided between a pair of rails 17
that are standed on the outer peripheral surface of the anvil
holding drum 8. In the rails 17, engaging grooves which open toward
counterpart rails 17 and which extend along the rotation center C1
are formed. The engaging protrusions 15 of the body section 12
engage with respective engaging grooves 17a in such a manner that
the engaging protrusions 15 can move along the rotation center C1,
with respect to anvil holding drum 8.
[0051] The cylindrical anvil holding drum 8 is provided with slits
16a that penetrate through the peripheral wall of the cylindrical
anvil holding drum 8 and that extend along the rotation center C1.
The cam protrusions 14 of the body sections 12 are inserted into
the anvil holding drum 8 via respective slits 16a.
[0052] The cam drum 9 is provided inside the anvil holding drum 8,
and a cam groove 9a is formed on the outer peripheral surface of
the cam drum 9. The leading end sections of the cam protrusions 14
are inserted into the cam groove 9a. The cam groove 9a guides the
cam protrusions 14 in such a manner that the anvil units 7 move
along the rotation center C1, in response to the rotation of the
anvil holding drum 8 with respect to the cam drum 9.
[0053] The sheet holding drum 5 and the anvil holding drum 8 are
fixed to each other and rotate integrally about the rotation center
C1. By contrast, the rotational position of the cam drum 9 is
fixed, regardless of the rotation of the sheet holding drum 5 and
the anvil holding drum 8. Therefore, the body section 12 moves
along the rotation center C1 in response to rotation of the sheet
holding drum 5 and the anvil holding drum 8 about the rotation
center C1.
[0054] That is, the holding mechanism 11 and the anvil holding drum
8 correspond to a support mechanism that supports rotatably each
anvil roller 10, via the rotary shaft 12a, in such a manner that
the anvil roller 10 can move along the rotation center C1 with
respect to the sheet holding drum 5, and the anvil roller 10 can be
in rolling contact with the sheet W in response to the movement of
the anvil roller 10 with respect to the sheet holding drum 5.
[0055] Specifically, in the anvil unit 7 positioned lowermost in
FIG. 2 and FIG. 3, the anvil roller 10 is disposed at a separation
position that is spaced apart from the sheet W held by the sheet
holding drum 5. In this state, the anvil unit 7 moves in a
direction of coming close to the sheet W along the rotation center
C1, in response to the counter-clockwise rotation, in FIG. 2, of
the sheet holding drum 5.
[0056] The anvil roller 10 crosses over the sheet W when the anvil
unit 7 is displaced up to the topmost position in FIG. 2 and the
FIG. 3. When the sheet holding drum 5 further rotates
counter-clockwise from this state, the anvil unit 7 starts moving
toward the separation position.
[0057] In the ultrasonic welding device 1, thus, each anvil roller
10 reciprocates over the sheet W, in the welding range D1 of FIG.
1, within the range E1 of FIG. 2. The sheet W is welded during this
reciprocating movement. The position of each anvil roller 10 with
respect to the sheet holding drum 5 in the range E1 corresponds to
a welding position.
[0058] The anvil rollers 10 will be explained next with respect to
FIG. 3 and FIG. 5.
[0059] The anvil rollers 10 are rollers made of metal (for
instance, high-chromium steel, or high-carbon steel).
[0060] Each anvil roller 10 is provided with a supported section 19
that is rotatably supported by the holding mechanism 11, via the
rotary shaft 12a; an outer peripheral section 18 over which the
sheet W can be welded between the ultrasonic horn 6 and the outer
peripheral section 18 during rolling contact with the sheet W; a
thin section 21 that is provided between the supported section 19
and the outer peripheral section 18; and two vibrationproof members
22 that are provided on the thin section 21.
[0061] The supported section 19 is a boss portion that is rotatably
supported, via the rotary shaft 12a, by the holding mechanism 11,
in order to allow rolling contact of the anvil roller 10 with the
sheet W in response to the movement of the anvil roller 10 between
the welding position and the separation position. A through-hole
19a for insertion of the rotary shaft 12a is formed in the
supported section 19.
[0062] The outer peripheral section 18 has a welding surface over
which the sheet W can be welded between the ultrasonic horn 6 and
the outer peripheral section 18 during rolling contact with the
sheet W. Specifically, the outer peripheral section 18 has a pair
of welding sections 18a that protrude outward, in the diameter
direction of the outer peripheral section 18, and that extend over
the entire circumference about the rotary shaft 12a. The spacing
between the welding sections 18a corresponds to the spacing D2 of
the weld section S in FIG. 1. That is, the outer peripheral surface
of the welding sections 18a corresponds to the welding surface over
which the sheet W is welded between the welding sections 18a and
the ultrasonic horn 6.
[0063] The thin section 21 is a portion that is formed through
recessing of the anvil roller 10 from both sides in the axial
direction of the rotary shaft 12a.
[0064] A thickness dimension D4 of the thin section 21, in the
axial direction of the rotary shaft 12a, is smaller than a
thickness dimension D5 of the supported section 19 and a thickness
dimension D3 of the outer peripheral section 18. The thickness
dimension D5 of the supported section 19 is smaller than the
thickness dimension D3 of the outer peripheral section 18.
[0065] As a result, the weight of the anvil roller 10 can be
reduced as compared with a cylindrical anvil roller having just the
through-hole 19a alone formed therein.
[0066] The thin section 21 is provided over the entire
circumference about the rotary shaft 12a.
[0067] The vibrationproof members 22 are formed of a material that
can deform elastically (for instance, a rubber material such as
silicon rubber or synthetic rubber, or a synthetic resin material).
By deforming elastically, the vibrationproof members 22 reduce the
vibration of the anvil roller 10.
[0068] The two vibrationproof members 22 are bonded to two
respective reverse faces 18b, with respect to the welding surface
of the outer peripheral section 18, as defined by the thin section
21. The reverse faces 18b are tilted by an angle of 20.degree. with
respect to the axis of the rotary shaft 12a, and the vibrationproof
members 22 are provided over the entire circumference of the
reverse faces 18b about the rotary shaft 12a.
[0069] The vibrationproof members 22 are provided only over part of
the thin section 21. That is, the vibrationproof members 22 are
formed over a given thickness in the entire circumference about the
rotary shaft 12a. A clearance is thus formed between the
vibrationproof members 22 and the supported section 19.
[0070] As explained above, vibration in the anvil roller 10 can be
suppressed by the vibrationproof members 22 that are provided on
the thin section 21. Accordingly, it becomes possible to reduce the
weight of the anvil roller 10, through formation of the thin
section 21, and, at the same time, to prevent the occurrence of
noise that accompanies this reduction in weight.
[0071] The following effects can be obtained according to the above
embodiment.
[0072] According to the above embodiments, the vibrationproof
members 22 are provided on the reverse faces 18b with respect to
the welding surface (outer peripheral surface of the welding
sections 18a) that receives ultrasonic vibration from the
ultrasonic horn 6. As a result, vibration of the anvil roller 10
can be suppressed efficiently at a position in the immediate
vicinity of a vibration source.
[0073] According to the above embodiment, the thin section 21 is
provided over the entire circumference about the rotary shaft 12a;
as a result, the weight of the anvil roller 10 about the rotary
shaft 12a is equalized, and the rotational stability of the anvil
roller 10 can be increased thereby.
[0074] Therefore, the above embodiment allows reducing, more
reliably, generation of noise due to vibration of the anvil roller
10, thanks to of the noise reduction effect derived from the
rotational stability of the anvil roller 10, and the noise
reduction effect derived from the vibrationproof members 22 that
are provided over the entire circumference about the rotary shaft
12a.
[0075] According to the above embodiment, the vibrationproof
members 22 are provided only over part of the thin section 21;
accordingly, this allows suppressing an increase in the weight of
the anvil roller 10 caused by an excessively large vibrationproof
member.
[0076] According to the above embodiment, the thickness dimension
D5 of the supported section 19 is greater than the thickness
dimension D4 of the thin section 21. Accordingly, the strength of
the supported section 19 that is supported by the rotary shaft 12a
can be secured, while reducing the weight of the anvil roller 10
thanks to the thin section 21.
[0077] By setting the thickness dimension D5 of the supported
section 19 to be smaller than the thickness dimension D3 of the
outer peripheral section 18, it becomes possible to reduce the
weight of the anvil roller 10 while securing the necessary strength
in the supported section 19.
[0078] The anvil roller 10 of an ultrasonic welding device
according to a second embodiment of the present invention will be
explained next with reference to FIG. 6. Portions identical to
those in the first embodiment will be denoted by the same reference
symbols, and an explanation thereof will be omitted.
[0079] The anvil roller 10 according to the second embodiment is
provided with a rounded section 18c that is formed between the
outer peripheral section 18 and the thin section 21, and a rounded
section 21a that is formed between the thin section 21 and the
supported section 19.
[0080] The rounded sections 18c, 21a are provided over the entire
circumference about the rotary shaft 12a (see FIG. 3).
[0081] The outer peripheral section 18 and the supported section 19
are connected to the thin section 21 via the rounded sections 18c,
21a. Abrupt changes in the cross-sectional area of the anvil roller
10 between the thin section 21 and the outer peripheral section 18,
and between the thin section 21 and the supported section 19, can
be suppressed as a result.
[0082] Therefore, it becomes possible to suppress concentration of
stress at the boundary portions between the thin section 21 and the
outer peripheral section 18, and between the thin section 21 and
the supported section 19, upon application of ultrasonic vibration
from the ultrasonic horn 6 to the anvil roller 10. The fatigue
strength of the anvil roller 10 can be enhanced as a result.
[0083] Herein there may be provided just one from among the rounded
sections 18c, 21a, in which case a fatigue strength enhancing
effect can be elicited by the one of the rounded sections.
[0084] In the anvil roller 10 according to the second embodiment,
the vibrationproof members 22 are provided so as to be in close
contact with the entire surface of the rounded section 18c. In the
vibrationproof members 22, inner surfaces 22a that face toward the
supported section 19 are tilted by an angle of 20.degree. with
respect to the axis of the rotary shaft 12a, as in the first
embodiment.
[0085] In the above embodiments, the vibrationproof members 22 are
provided only over part of the thin section 21, but the
vibrationproof members 22 may be provided over the entire range of
the thin section 21. For instance, the vibrationproof members 22
can be filled up into the thin section 21.
[0086] In the above embodiments, anvil rollers 10 have been
explained that have the welding surface (welding sections 18a)
provided over a 360.degree. area about the rotary shaft 12a, but
the formation area of the welding surface can be set to less than
360.degree. about the rotary shaft 12a.
[0087] Specifically, the formation area (angle) of the welding
surface can be set to have a circumferential length that exceeds
the welding range D1 (FIG. 1) of the sheet W. For instance, a
semi-circular anvil roller can be used herein.
[0088] Using circular anvil rollers 10 having a circumferential
length that exceeds the welding range D1 of the sheet W, as in the
above embodiments, has the following advantage. The frequency of
replacement of the anvil roller 10, in a case where, for instance,
part of the welding surface of the anvil roller 10 is damaged, can
be reduced through adjustment of the mounting position of the anvil
roller 10 in such a manner that welding can be carried out using a
portion other than the damaged portion.
[0089] The specific embodiments described above include an
invention having the following features.
[0090] In order to solve the above problems, the inventors of the
present application conceived of an invention pertaining to an
anvil roller in which a thin section is formed between an outer
peripheral section having a welding surface and a supported section
that is supported by a rotary shaft, the thickness of the thin
section being smaller than the thickness of the outer peripheral
section.
[0091] When the weight of the anvil roller is thus reduced through
formation of the thin section, however, the natural frequency of
the anvil roller increases, and a new problem arises thereupon,
namely the occurrence of noise derived from resonance of the anvil
roller when the anvil roller receives ultrasonic vibration from the
ultrasonic horn.
[0092] In order to solve this new problem, therefore, the present
invention provides an anvil roller, used in an ultrasonic welding
device that includes: a holding member that holds an object to be
welded; an ultrasonic horn that applies ultrasonic vibration to the
object to be welded held by the holding member; an anvil roller for
welding the object to be welded, between the ultrasonic horn and
the anvil roller; and a support mechanism that supports the anvil
roller via a rotary shaft in such a manner that the anvil roller
can move with respect to the holding member, and that the anvil
roller can come into rolling contact with the object to be welded
in response to the movement of the anvil roller with respect to the
holding member, the anvil roller including: a supported section
that is rotatably supported by the holding mechanism via the rotary
shaft; an outer peripheral section having a welding surface over
which the object to be welded can be welded between the ultrasonic
horn and the outer peripheral section during rolling contact with
the object to be welded; a thin section that is formed between the
supported section and the outer peripheral section in such a manner
that the thickness of the thin section is smaller than the
thickness of the outer peripheral section in an axial direction of
the rotary shaft; and a vibrationproof member provided on the thin
section.
[0093] According to the present invention, vibration occurring in
the anvil roller can be suppressed by the vibrationproof member
that is provided on the thin section. Accordingly, it becomes
possible to reduce the weight of the anvil roller, through
formation of the thin section, and, at the same time, to prevent
the occurrence of noise that accompanies this reduction in
weight.
[0094] In the anvil roller, preferably, the vibrationproof member
is provided on a reverse face, with respect to the welding surface,
of the outer peripheral section, as defined by the thin
section.
[0095] In this aspect, the vibrationproof member is provided on the
reverse face with respect to the welding surface that receives the
ultrasonic vibration from the ultrasonic horn. Accordingly,
vibration of the anvil roller can be suppressed efficiently at a
position in the immediate vicinity of a vibration source.
[0096] In the anvil roller, preferably, the thin section is
provided over the entire circumference about the rotary shaft, and
the vibrationproof member is provided over the entire circumference
of the reverse face about the rotary shaft.
[0097] In this aspect, the thin section is provided over the entire
circumference about the rotary shaft; as a result, the weight of
the anvil roller about the rotary shaft is equalized, and the
rotational stability of the anvil roller can be increased
thereby.
[0098] Therefore, the above aspect allows reducing generation of
noise due to vibration of the anvil roller more reliably, by virtue
of the noise reduction effect derived from the rotational stability
of the anvil roller, and the noise reduction effect derived from
the vibrationproof member that is provided over the entire
circumference about the rotary shaft.
[0099] The vibrationproof member can be filled up into the entirety
of a groove of the anvil roller that is defined by the thin
section, but, preferably, the vibrationproof member is provided
only over part of the thin section.
[0100] This aspect allows suppressing an increase in the weight of
the anvil roller caused by an excessively large vibrationproof
member.
[0101] In the anvil roller, preferably, the thickness of the
supported section is greater than the thickness of the thin section
in the axial direction of the rotary shaft.
[0102] In this aspect, the strength of the supported section that
is supported by the rotary shaft can be secured, while reducing the
weight of the anvil roller by virtue of the thin section.
[0103] By setting the thickness of the supported section to be
smaller than the thickness of the outer peripheral section, it
becomes possible to reduce the weight of the anvil roller while
securing the necessary strength in the supported section.
[0104] The present invention further provides an ultrasonic welding
device that is provided with: a holding member that holds an object
to be welded; an ultrasonic horn that applies ultrasonic vibration
to the object to be welded held by the holding member; the anvil
roller for welding the object to be welded, between the ultrasonic
horn and the anvil roller; and a support mechanism that supports
the anvil roller via a rotary shaft in such a manner that the anvil
roller can move with respect to the holding member, and that the
anvil roller can come into rolling contact with the object to be
welded in response to the movement of the anvil roller with respect
to the holding member.
* * * * *