U.S. patent application number 16/161686 was filed with the patent office on 2019-05-02 for bag opening apparatus and bag opening method.
The applicant listed for this patent is TOYO JIDOKI CO., LTD.. Invention is credited to Kenji HAYASHI, Yuuki MATSUMURA.
Application Number | 20190127100 16/161686 |
Document ID | / |
Family ID | 63998497 |
Filed Date | 2019-05-02 |
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United States Patent
Application |
20190127100 |
Kind Code |
A1 |
MATSUMURA; Yuuki ; et
al. |
May 2, 2019 |
BAG OPENING APPARATUS AND BAG OPENING METHOD
Abstract
A bag opening apparatus and a bag opening method capable of
efficiently opening a bag body in a short period of time are
provided. A bag opening apparatus includes a gap formation unit
which bends at least a front wall portion, of the front wall
portion and a back wall portion that constitute a mouth portion of
a bag body, so as to form a gap. When a first press drive member
presses a first holding unit against the front wall portion, a
contact part of the first holding unit is swung against urging
force of an urging part of the first holding unit to bend the front
wall portion.
Inventors: |
MATSUMURA; Yuuki;
(Yamaguchi-ken, JP) ; HAYASHI; Kenji;
(Yamaguchi-ken, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
TOYO JIDOKI CO., LTD. |
Tokyo |
|
JP |
|
|
Family ID: |
63998497 |
Appl. No.: |
16/161686 |
Filed: |
October 16, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B65B 43/36 20130101;
B65B 43/30 20130101; B65B 43/28 20130101; B65B 43/465 20130101;
B31B 70/003 20170801 |
International
Class: |
B65B 43/28 20060101
B65B043/28; B65B 43/46 20060101 B65B043/46 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 27, 2017 |
JP |
2017-208575 |
Claims
1. A bag opening apparatus comprising a gap formation unit which
bends at least a front wall portion, of the front wall portion and
a back wall portion that constitute a mouth portion of a bag body,
so as to form a gap between the front wall portion and the back
wall portion, wherein: the gap formation unit includes a first
holding unit and a first press drive member which moves the first
holding unit between a position where the first holding unit is
separated from the front wall portion and a position where the
first holding unit is pressed against the front wall portion, the
first holding unit includes a contact part, a support part which
swingably supports the contact part, and an urging part which urges
the contact part via the support part, and when the first press
drive member presses the first holding unit against the front wall
portion, the contact part is swung against urging force of the
urging part while the contact part is in contact with the front
wall portion so as to bend the front wall portion.
2. The bag opening apparatus as defined in claim 1, wherein: the
gap formation unit further includes a second holding unit, the
first press drive member moves not only the first holding unit but
also the second holding unit between the position where the first
holding unit and the second holding unit are separated from the
front wall portion and the position where the first holding unit
and the second holding unit are pressed against the front wall
portion, and when the first press drive member presses the first
holding unit and the second holding unit against the front wall
portion, the contact part of the first holding unit is swung so as
to approach the second holding unit while the contact part of the
first holding unit is in contact with the front wall portion.
3. The bag opening apparatus as defined in claim 2, wherein: the
second holding unit includes a contact part, a support part which
swingably supports this contact part, and an urging part which
urges this contact part via the support part, and when the first
press drive member presses the first holding unit and the second
holding unit against the front wall portion, the contact part of
the second holding unit Is swung against urging force of the urging
part of the second holding unit so as to approach the contact part
of the first holding unit while the contact part of the second
holding unit is in contact with the front wall portion.
4. The bag opening apparatus as defined in claim 1, further
comprising an air blowing unit which ejects air toward the gap.
5. The bag opening apparatus as defined in claim 2, further
comprising an air blowing unit which ejects air toward the gap.
6. The bag opening apparatus as defined in claim 3, further
comprising an air blowing unit which ejects air toward the gap.
7. The bag opening apparatus as defined in claim 3, wherein: the
gap formation unit further includes: a third holding unit and a
fourth holding unit; and a second press drive member which moves
the third holding unit and the fourth holding unit between a
position where the third holding unit and the fourth holding unit
are separated from the back wall portion and a position where the
third holding unit and the fourth holding unit are pressed against
the back wall portion, and in a state where the contact part of the
first holding unit and a contact part of the third holding unit are
opposed to each other via the front and back wall portions and the
contact part of the second holding unit and a contact part of the
fourth holding unit are opposed to each other via the front and
back wall portions, the first press drive member presses the first
holding unit and the second holding unit against the front wall
portion, and the second press drive member presses the third
holding unit and the fourth holding unit against the back wall
portion.
8. The bag opening apparatus as defined in claim 1, wherein: the
gap formation unit further includes a receiving part which are
disposed on a side of the back wall portion and has a receiving
surface facing the back wall portion, and the first press drive
member presses the first holding unit against the front wall
portion in a state where the front wall portion and the back wall
portion are sandwiched by the first holding unit and the receiving
surface.
9. The bag opening apparatus as defined in claim 2, wherein: the
gap formation unit further Includes a receiving part which are
disposed on a side of the back wall portion and has a receiving
surface facing the back wall portion, and the first press drive
member presses the first holding unit against the front wall
portion in a state where the front wall portion and the back wall
portion are sandwiched by the first holding unit and the receiving
surface.
10. The bag opening apparatus as defined in claim 3, wherein: the
gap formation unit further includes a receiving part which are
disposed on a side of the back wall portion and has a receiving
surface facing the back wall portion, and the first press drive
member presses the first holding unit against the front wall
portion in a state where the front wall portion and the back wall
portion are sandwiched by the first holding unit and the receiving
surface.
11. The bag opening apparatus as defined in claim 8, wherein the
receiving part includes a first elastic member forming the
receiving surface.
12. The bag opening apparatus as defined in claim 9, wherein the
receiving part includes a first elastic member forming the
receiving surface.
13. The bag opening apparatus as defined in claim 10, wherein the
receiving part includes a first elastic member forming the
receiving surface.
14. The bag opening apparatus as defined in claim 1, wherein: the
first holding unit includes: a first link which is attached to the
first press drive member and swingably supports one side of the
support part of the first holding unit, and a second link which is
attached to the first press drive member so as to be capable of
moving back and forth and swingably supports another side of the
support part of the first holding unit, and when the first press
drive member presses the first holding unit against the front wall
potion, the urging part of the first holding unit urges the contact
part of the first holding unit, via the second link and the support
part of the first holding unit, in a direction including a
component of a direction opposing a direction in which the contact
part of the first holding unit is swung.
15. The bag opening apparatus as defined in claim 1, wherein the
contact part includes a second elastic member.
16. The bag opening apparatus as defined in claim 1, further
comprising a pair of grippers which holds both side portions of the
bag body, wherein before or while the first press drive member
presses the first holding unit against the front wall portion to
cause the contact part of the first holding unit to swing, at least
one of the grippers is moved in such a manner that a distance
between the grippers is reduced.
17. A bag opening method causing a bag opening apparatus to bend at
least a front wall portion, of the front wall portion and a back
wall portion that constitute a mouth portion of a bag body, so as
to form a gap between the front wall portion and the back wall
portion, wherein: the bag opening apparatus includes a gap
formation unit having: a first holding unit; and a first press
drive member which moves the first holding unit between a position
where the first holding unit is separated from the front wall
portion and a position where the first holding unit is pressed
against the front wall portion, the first holding unit includes a
contact part, a support part which swingably supports the contact
part, and an urging part which urges the contact part via the
support part, and the bag opening method includes a step of bending
the front wall portion by causing the first press drive member to
press the first holding unit against the front wall portion in such
a manner that the contact part is swung against urging force of the
urging part while the contact part is in contact with the front
wall portion.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application Is based upon and claims the benefit of
priority from Japanese Patent Application No. 2017-208575, filed on
Oct. 27, 2017; the entire contents of which are incorporated herein
by reference.
TECHNICAL FIELD
[0002] The present invention is related to a bag opening apparatus
and a bag opening method.
BACKGROUND ART
[0003] Conventionally, as apparatuses for opening the mouth portion
of a bag body, such as a package bag, apparatuses adopting various
methods have been proposed. For example, according to a device
using a suction cup for opening a bag body, the suction cup is kept
in contact with a bag surface over a predetermined time until an
appropriate negative pressure is formed between the suction cup and
the bag surface, and then, the suction cup is moved together with
the bag surface so that the mouth portion is opened.
[0004] On the other hand, Japanese examined utility model
(registration) application publication No. 3-22084 discloses an
apparatus which opens a flat film tube without using a suction cup.
In this apparatus, rollers forming a pair are once moved outward in
the width direction in a state of being in contact with a tube
surface, and thereafter, the rollers forming a pair are moved
inward in the width direction using the elastic force of a spring
while the rotation of each of the rollers is restricted. As a
result, the tube surface is dragged to the pair of rollers moving
Inward in the width direction, so that a gap is formed in the mouth
portion of the tube.
[0005] Further, Japanese patent application publication No.
2013-82487 discloses an apparatus which opens a package bag made of
paper, nonwoven fabric or the like. In this apparatus, a package
bag is opened by moving a pair of conveyance claws in a closed
state while a part of the package bag is nipped between the closed
conveyance claws.
SUMMARY OF INVENTION
Technical Problem
[0006] In an opening device using a suction cup, a period of time
for placing the suction cup in a halt state is needed in order to
make the suction cup to suck a bag surface as described above. This
period of time becomes a bottleneck for speeding up the opening
process of a bag body. In particular, when the opening process of a
bag body is combined with another process such as a packaging
process, the period of time required for the suction of a suction
cup can be a major factor impeding improvement of the performance
of the whole processing.
[0007] In addition, in the apparatus disclosed in Japanese examined
utility model (registration) application publication No. 3-22084,
prior to forming a gap in the mouth portion of a tube by moving a
pair of rollers inward in the width direction, a preliminary
operation which makes the pair of rollers move outward in the width
direction is needed. This preliminary operation is also one of the
factors hindering the improvement of the processing performance. In
particular, when it is necessary to obtain a large gap formed in
the mouth portion of a tube as in the case where the tube width is
large, it is also necessary to make larger the displacement amount
of the tube. In this case, it is necessary to increase the amount
of inward movement of the pair of rollers in the width direction;
however, for this purpose, it is necessary to increase the amount
of outward movement of the pair of rollers in the width direction
in the preliminary operation, and thus the time required for the
processing is greatly increased. As described above, an apparatus
and a method which need to perform the preliminary operation
depending on the actual opening operation are not necessarily
suitable for high-speed processing.
[0008] Moreover, in the apparatus disclosed in Japanese patent
application publication No. 2013-82487, the conveyance claws
forming two pairs (that is, four conveyance claws) are alternately
arranged in a state where a package bag is positioned therebetween,
and the package bag is bent and folded in accordance with the shape
of the conveyance claws. In this case, the package bag is gripped
and opened by the conveyance claws in a sharply folded state.
Therefore, in a case where a package bag is opened by using the
apparatus of Japanese patent application publication No.
2013-82487, depending on the material of the package bag,
folding/bending marks remain in the package bag and thus the
aesthetic appearance and the quality of the package bag are
impaired.
[0009] Furthermore, in the apparatus of Japanese examined utility
model (registration) application publication No. 3-22084 and the
apparatus of Japanese patent application publication No. 2013-82487
described above, the action direction of the holding members
(specifically, a pair of rollers or a pair of conveyance claws) for
bringing the holding members into contact with a bag surface and
the action direction of the holding members for opening a bag body
are opposite to each other. Thus, compared to a case where the
action direction of the holding members for bringing the holding
members into contact with a bag surface is the same as the action
direction of the holding members for opening the bag, the opening
operations of the apparatuses disclosed in Japanese examined
utility model (registration) application publication No. 3-22084
and the opening of the device of Japanese patent application
publication No. 2013-82487 are inefficient.
[0010] The present invention has been contrived in view of the
above circumstances, and an object thereof is to provide an
apparatus and a method capable of efficiently opening a bag body in
a short period of time. Another object of the present invention is
to provide an apparatus and a method capable of opening a bag body
while preventing folding marks from being formed on the bag
body.
Solution to Problem
[0011] One aspect of the present invention is directed to a bag
opening apparatus comprising a gap formation unit which bends at
least a front wall portion, of the front wall portion and a back
wall portion that constitute a mouth portion of a bag body, so as
to form a gap between the front wall portion and the back wall
portion, wherein: the gap formation unit includes a first holding
unit and a first press drive member which moves the first holding
unit between a position where the first holding unit is separated
from the front wall portion and a position where the first holding
unit is pressed against the front wall portion, the first holding
unit includes a contact part, a support part which swingably
supports the contact part, and an urging part which urges the
contact part via the support part, and when the first press drive
member presses the first holding unit against the front wall
portion, the contact part is swung against urging force of the
urging part while the contact part is in contact with the front
wall portion so as to bend the front wall portion.
[0012] The gap formation unit may further include a second holding
unit; the first press drive member may move not only the first
holding unit but also the second holding unit between the position
where the first holding unit and the second holding unit are
separated from the front wall portion and the position where the
first holding unit and the second holding unit are pressed against
the front wall portion; and when the first press drive member
presses the first holding unit and the second holding unit against
the front wall portion, the contact part of the first holding unit
may be swung so as to approach the second holding unit while the
contact part of the first holding unit is in contact with the front
wall portion.
[0013] The second holding unit may include a contact part, a
support part which swingably supports this contact part, and an
urging part which urges this contact part via the support part; and
when the first press drive member presses the first holding unit
and the second holding unit against the front wall portion, the
contact part of the second holding unit may be swung against urging
force of the urging part of the second holding unit so as to
approach the contact part of the first holding unit while the
contact part of the second holding unit is in contact with the
front wall portion.
[0014] The bag opening apparatus may further comprise an air
blowing unit which ejects air toward the gap.
[0015] The gap formation unit may further include: a third holding
unit and a fourth holding unit; and a second press drive member
which moves the third holding unit and the fourth holding unit
between a position where the third holding unit and the fourth
holding unit are separated from the back wall portion and a
position where the third holding unit and the fourth holding unit
are pressed against the back wall portion; and in a state where the
contact part of the first holding unit and a contact part of the
third holding unit are opposed to each other via the front and back
wall portions and the contact part of the second holding unit and a
contact part of the fourth holding unit are opposed to each other
via the front and back wall portions, the first press drive member
may press the first holding unit and the second holding unit
against the front wall portion, and the second press drive member
may press the third holding unit and the fourth holding unit
against the back wall portion.
[0016] The gap formation unit may further include a receiving part
which are disposed on a side of the back wall portion and has a
receiving surface facing the back wall portion; and the first press
drive member may press the first holding unit against the front
wall portion in a state where the front wall portion and the back
wall portion are sandwiched by the first holding unit and the
receiving surface.
[0017] The receiving part may include a first elastic member
forming the receiving surface.
[0018] The first holding unit may include: a first link which is
attached to the first press drive member and swingably supports one
side of the support part of the first holding unit, and a second
link which is attached to the first press drive member so as to be
capable of moving back and forth and swingably supports another
side of the support part of the first holding unit; and when the
first press drive member presses the first holding unit against the
front wall potion, the urging part of the first holding unit may
urge the contact part of the first holding unit, via the second
link and the support part of the first holding unit, in a direction
including a component of a direction opposing a direction in which
the contact part of the first holding unit is swung.
[0019] The contact part may include a second elastic member.
[0020] The bag opening apparatus may further comprise a pair of
grippers which holds both side portions of the bag body, wherein
before or while the first press drive member presses the first
holding unit against the front wall portion to cause the contact
part of the first holding unit to swing, at least one of the
grippers is moved in such a manner that a distance between the
grippers is reduced.
[0021] Another aspect of the present invention is directed to a bag
opening method causing a bag opening apparatus to bend at least a
front wall portion, of the front wall portion and a back wall
portion that constitute a mouth portion of a bag body, so as to
form a gap between the front wall portion and the back wall
portion, wherein: the bag opening apparatus includes a gap
formation unit having: a first holding unit; and a first press
drive member which moves the first holding unit between a position
where the first holding unit is separated from the front wall
portion and a position where the first holding unit is pressed
against the front wall portion, the first holding unit includes a
contact part, a support part which swingably supports the contact
part, and an urging part which urges the contact part via the
support part, and the bag opening method Includes a step of bending
the front wall portion by causing the first press drive member to
press the first holding unit against the front wall portion in such
a manner that the contact part is swung against urging force of the
urging part while the contact part is in contact with the front
wall portion.
[0022] According to the present invention, a bag body can be
efficiently opened in a short period of time. Further, according to
the present invention, a bag body can be opened while folding marks
are prevented from being formed on the bag body.
BRIEF DESCRIPTION OF DRAWINGS
[0023] FIG. 1 is a plan view illustrating a schematic configuration
of a bag opening apparatus according to a first embodiment.
[0024] FIG. 2 is a process diagram of a bag opening method
according to the first embodiment.
[0025] FIG. 3 is a process diagram of a bag opening method
according to the first embodiment.
[0026] FIG. 4 is a process diagram of a bag opening method
according to the first embodiment.
[0027] FIG. 5 is a plan view illustrating an example of a state of
a bag body which may occur in the apparatus and the method
according to the first embodiment.
[0028] FIG. 6 is a plan view illustrating a schematic configuration
of a bag opening apparatus according to a second embodiment.
[0029] FIG. 7 is a process diagram of a bag opening method
according to the second embodiment, showing a state in which the
bag opening apparatus is viewed from above.
[0030] FIG. 8 is a process diagram of the bag opening method
according to the second embodiment, showing a state in which the
bag opening apparatus is viewed from above.
[0031] FIG. 9 is a process diagram of the bag opening method
according to the second embodiment, showing a state in which the
bag opening apparatus is viewed from above.
[0032] FIG. 10 is a process diagram of the bag opening method
according to the second embodiment, showing a state in which the
bag opening apparatus is viewed from the side.
[0033] FIG. 11 is a process diagram of the bag opening method
according to the second embodiment, showing a state in which the
bag opening apparatus is viewed from the side.
[0034] FIG. 12 is a process diagram of the bag opening method
according to the second embodiment, showing a state in which the
bag opening apparatus is viewed from the side.
[0035] FIG. 13 is a process diagram of the bag opening method
according to the second embodiment, showing a state in which the
bag opening apparatus is viewed from the side.
[0036] FIG. 14 is a plan view illustrating a schematic
configuration of a bag opening apparatus according to a first
modified example.
DESCRIPTION OF EMBODIMENTS
[0037] Hereinafter, embodiments of the present invention will be
described with reference to the drawings.
[0038] In the following embodiments, bag opening apparatuses used
in a packaging machine will be described as an example, but the bag
opening apparatuses and bag opening methods described below may be
applied to any mechanism using a bag body of which the mouth
portion is opened. A packaging machine typically includes, in
addition to a bag opening apparatus, a device which introduces the
contents into a bag body through the opened mouth portion, a device
which closes and seals the mouth portion after the contents have
been introduced into the bag body, and other devices. The form of
the contents to be introduced into a bag body is not limited, and
it is possible to introduce contents in the form of gas, liquid,
gel or solid or contents having two or more forms, into a bag
body.
[0039] In a bag opening apparatus and a bag opening method
according to the embodiment described below, first, the close
contact between the front wall portion and the back wall portion at
the opening portion of a bag body is partially released by forming
a gap in the mouth portion, and then the whole of the bag body is
opened by blowing compressed air into the inside of the bag body
through the gap in the mouth portion.
[0040] The opening process of a bag body may be performed through a
plurality of processes in this way, but may be performed in a
single process. Specifically, the process of forming a gap in the
mouth portion of a bag body itself also corresponds to the opening
process of a bag body in a broad sense. Therefore, if the mouth
portion of a bag body can be opened to a desired state only by the
process of forming a gap in the mouth portion of the bag body,
other processes (for example, a process of blowing compressed air
into the inside of the bag body) are not necessarily required to be
performed.
[0041] The bag opening apparatus described below comprises: a gap
formation unit which bends at least the front wall portion, of the
front wall portion and the back wall portion constituting the mouth
portion of a bag body, in such a manner that a gap is formed
between the front wall portion and the back wall portion at the
mouth portion; and an air blowing unit which blows air toward the
gap. Specifically, as typical examples of a bag opening apparatus
according to the present invention, there are a bag opening
apparatus which bends both the front wall portion and the back wall
portion of a bag body, and a bag opening apparatus which bends only
one of the front wall portion and the back wall portion. In the
following first embodiment, a bag opening apparatus that bends each
of the front wall portion and the back wall portion of a bag body
to form a gap will be exemplified. On the other hand, in the second
embodiment below, a bag opening apparatus that bends only the front
wall portion, of the front wall portion and the back wall portion
of a bag body, to form a gap is exemplified.
First Embodiment
[0042] FIG. 1 is a plan view illustrating a schematic configuration
of a bag opening apparatus 10 according to a first embodiment.
[0043] The mouth portion 101 of a bag body 100 to be supplied to
the bag opening apparatus 10 is closed. Specifically, in a state in
which both the side portions (in particular, both the side edge
portions) of a bag body 100 are held by a pair of grippers 110 and
the front wall portion 102 and the back wall portion 103 of the bag
body 100 are in close contact with each other, the bag body 100 is
supplied to the bag opening apparatus 10. In particular, each bag
body 100 is transferred together with a pair of grippers 110 along
a predetermined track extending in the horizontal direction (for
example, a straight line track, a circle track, or a track formed
by combining a straight line and a curved line) so as to
sequentially visit a plurality of stations, and is intermittently
stopped at the opening station S1 where the bag opening apparatus
10 is provided. Each bag body 100 is opened by the bag opening
apparatus 10 while stopping at the opening station S1. A bag body
100 having the mouth portion 101 opened by the bag opening
apparatus 10 is intermittently transferred toward the other
stations (a content introduction station, a sealing station, etc.)
provided in the subsequent stages.
[0044] A pair of grippers 110 is provided so as to be movable in a
direction of the horizontal direction parallel to the extension
direction (see the arrow "Y" in FIG. 1) in which a bag body 100
extends. When the bag opening apparatus 10 is brought into contact
with a bag body 100 at the opening station S1, the grippers 110
forming a pair are disposed at positions separated relatively from
each other, the bag body 100 is strained in the Y direction by the
pair of grippers 110, and each of the front wall portion 102 and
the back wall portion 103 of the bag body 100 is placed in a
stretched state without looseness. On the other hand, when the bag
opening apparatus 10 bends the front wall portion 102 and the back
wall portion 103 as described later, the grippers 110 forming a
pair are disposed in positions relatively close to each other, the
tension of the bag body 100 in the Y direction is released, and
each of the front wall portion 102 and the back wall portion 103 of
the bag body 100 is placed in a slack state.
[0045] The gap formation unit 11 of the bag opening apparatus 10 of
the present embodiment includes: a first press drive member 23 (a
first movement arm) and a second press drive member 24 (a second
movement arm); a first holding unit 25 and a second holding unit 26
which are attached to the first press drive member 23; and a third
holding unit 27 and a fourth holding unit 28 which are attached to
the second press drive member 24.
[0046] A first opening unit 21 includes the first press drive
member 23, the first holding unit 25 and the second holding unit
26, and moves in an integrated fashion. Similarly, a second opening
unit 22 includes the second press drive member 24, the third
holding unit 27 and the fourth holding unit 28, and moves in an
integrated fashion. A bag body 100 gripped by the grippers 110 is
disposed between the first opening unit 21 and the second opening
unit 22, the first opening unit 21 is arranged on the front surface
side of the bag body 100, and the second opening unit 22 is
arranged on the back surface side of the bag body 100. The first to
the fourth holding units 25 to 28 are disposed above the grippers
110 in terms of the vertical direction, and when the first to the
fourth holding units 25 to 28 contact the bag body 100, the first
to the fourth holding units 25 to 28 contact the bag body 100 at
positions close to the mouth portion 101.
[0047] Each of the first press drive member 23 and the second press
drive member 24 is provided so as to be driven to be horizontally
movable in directions toward and away from each other (see an arrow
"X" In FIG. 1) by a drive unit which is not illustrated (such as an
air cylinder or a motor), and moves forward and backward relative
to the bag body 100.
[0048] The first press drive member 23 moves the first holding unit
25 and the second holding unit 26 between a position where the
first holding unit 25 and the second holding unit 26 are distanced
from the front wall portion 102 of a bag body 100 and a position
where the first holding unit 25 and the second holding unit 26 are
pressed against the front wall portion 102. The second press drive
member 24 moves the third holding unit 27 and the fourth holding
unit 28 between a position where the third holding unit 27 and the
fourth holding unit 28 are distanced from the back wall portion 103
of a bag body 100 and a position where the third holding unit 27
and the fourth holding unit 28 are pressed against the back wall
portion 103.
[0049] The first holding unit 25 and the second holding unit 26 are
provided at positions distanced from each other in the Y direction,
and the third holding unit 27 and the fourth holding unit 28 are
provided at positions distanced from each other in the Y direction.
The first holding unit 25 and the second holding unit 26 are each
arranged to protrude from the first press drive member 23 toward
the bag body 100. The third holding unit 27 and the fourth holding
unit 28 of the second opening unit 22 are each arranged to protrude
from the second press drive member 24 toward the bag body 100.
[0050] For example, when the first press drive member 23 is moved
in a direction in which the first press drive member 23 approaches
the second press drive member 24, the first holding unit 25 and the
second holding unit 26 contact areas of the front wall portion 102
of the bag body 100 which are distanced from each other in the Y
direction, and the first holding unit 25 and the second holding
unit 26 are pressed against the front wall portion 102. Similarly,
when the second press drive member 24 is moved in a direction in
which the second press drive member 24 approaches the first press
drive member 23, the third holding unit 27 and the fourth holding
unit 28 contact areas of the back wall portion 103 of the bag body
100 which are distanced from each other in the Y direction, and the
third holding unit 27 and the fourth holding unit 28 are pressed
against the back wall portion 103.
[0051] Each of the first holding unit 25, the second holding unit
26, the third holding unit 27, and the fourth holding unit 28
includes a contact part 31, a support part 32 that swingably
supports the contact part 31, and an urging part 33 which urges the
contact part 31 via the support part 32.
[0052] The contact parts 31 of the first holding unit 25 and the
second holding unit 26 are regions which directly contact the front
wall portion 102 when the first press drive member 23 presses the
first holding unit 25 and the second holding unit 26 against the
front wall portion 102. Further, the contact parts 31 of the third
holding unit 27 and the fourth holding unit 28 are regions which
directly contact the back wall portion 103 when the second press
drive member 24 presses the third holding unit 27 and the fourth
holding unit 28 against the back wall portion 103. The contact
parts 31 of the present embodiment include an elastic member
(second elastic member). Although the elastic member of the contact
parts 31 is not limited, the elastic member of the contact parts 31
is preferably a member having a high friction coefficient and
excellent adhesion, and typically silicone or urethane may be used
as the elastic member of the contact parts 31. As will be described
later, in the bag opening apparatus 10 of the present embodiment,
the contact parts 31 of the first holding unit 25 to the fourth
holding unit 28 displace the bag surfaces of a bag body 100 (that
is, the front wall portion 102 and the back wall portion 103) from
each other due to the friction force so as to form a gap in the
mouth portion 101 of the bag body 100. Therefore, by configuring
the contact parts 31 of the first holding unit 25 to the fourth
holding unit 28 with an elastic member as described above, the grip
force of the contact parts 31 is secured and thereby the opening
process of a bag body 100 is stabilized, and further, it is
possible to make a bag body 100 less likely to be damaged by the
contact parts 31.
[0053] In the illustrated first holding unit 25, a link mechanism
is constituted by a first link 34, a second link 35, and the
support part 32. The first link 34 is fixedly attached to the first
press drive member 23, protrudes from the first press drive member
23 toward a bag body 100 (specifically, in the horizontal direction
(that is, the X direction) perpendicular to the Y direction), and
supports one side of the support part 32 via a second support shaft
42 in a swingable manner. A distal end portion on one side of the
second link 35 swingably supports the other side of the support
part 32 via a first support shaft 41. The other side of the second
link 35 is swingably attached to the first press drive member 23
via a third support shaft 43 (a fastening part), and is provided to
be movable back and forth in a direction toward the bag body 100
and in a direction away from the bag body 100.
[0054] The illustrated second link 35 has a reduced diameter
portion 36 having a small diameter in part between the third
support shaft 43 and a connecting portion between the second link
35 and the support part 32 of the first holding unit 25. An urging
part 33 constituted by a compressed spring is disposed in this
reduced diameter portion 36. The urging part 33 of the first
holding unit 25 urges the support part 32 and the second link 35 of
the first holding unit 25 toward the connection portion between the
second link 35 and the support part 32 of the first holding unit.
Specifically, the urging part 33 of the first holding unit 25 urges
the contact part 31 of the first holding unit 25, via the support
part 32 and the second link 35 of the first holding unit 25, in a
direction including a component of the direction opposing a
direction in which the contact part 31 of the first holding unit 25
swings when the first press drive member 23 presses the first
holding unit 25 against the front wall portion 102. In particular,
the urging part 33 of the first holding unit 25 of the present
embodiment is combined with the above-described link mechanism to
urge the second link 35 and the support part 32 in such a manner
that the contact part 31 of the first holding unit 25 is distanced
from the contact part 31 of the second holding unit 26.
[0055] The support part 32 of the first holding unit 25 is disposed
in a posture tilted with respect to the movement direction (that
is, the X direction) of the first opening unit 21 and the second
opening unit 22. In particular, the tip of the support part 32 of
the first holding unit 25 on the side where the contact part 31 is
disposed (specifically, the tip relatively close to the bag body
100) is arranged closer to the second holding unit 26 in the Y
direction than the opposite tip (specifically, the tip relatively
farther from the bag body 100). Thus, when the first holding unit
25 (in particular, the contact part 31) Is pressed against the bag
body 100, the support part 32 and the contact part 31 of the first
holding unit 25 swing so as to approach the support part 32 and the
contact part 31 of the second holding unit 26.
[0056] The second holding unit 26 has a configuration similar to
the above-described first holding unit 25. Specifically, the second
holding unit 26 includes a first link 34, a second link 35, a
reduced diameter portion 36, a first support shaft 41, a second
support shaft 42 and a third support shaft 43 in addition to the
contact part 31, the support part 32 and the urging part 33.
However, the urging part 33 of the second holding unit 26 is
combined with the link mechanism constituted by the support part
32, the first link 34 and the second link 35 of the second holding
unit 26 to urge the second link 35 and the support part 32 in such
a manner that the contact part 31 of the second holding unit 26 is
distanced from the contact part 31 of the first holding unit 25.
Specifically, the urging part 33 of the second holding unit 26
urges the contact part 31 of the second holding unit 26, via the
support part 32 and the second link 35 of the second holding unit
26, in a direction including a component of the direction opposing
a direction in which the contact part 31 of the second holding unit
26 swings when the first press drive member 23 presses the second
holding unit 26 against the front wall portion 102.
[0057] The third holding unit 27 and the fourth holding unit 28
attached to the second press drive member 24 have configurations
similar to the first holding unit 25 and the second holding unit 26
attached to the first press drive member 23, and each Include a
contact part 31, a support part 32, an urging part 33, a first link
34, a second link 35, a reduced diameter portion 36, a first
support shaft 41, a second support shaft 42, and a third support
shaft 43.
[0058] In each of the third holding unit 27 and the fourth holding
unit 28, the first link 34 is fixedly attached to the second press
drive member 24, protrudes from the second press drive member 24
towards the bag body 100 in the X direction, and supports one side
of the support part 32 via the second support shaft 42 in a
swingable manner. Further, the second link 35 of each of the third
holding unit 27 and the fourth holding unit 28 is swingably
attached to the second press drive member 24 via the third support
shaft 43 (a fastening part), is provided to be movable back and
forth in a direction towards the bag body 100 and in a direction
away from the bag body 100, and supports the other side of the
support part 32 via the first support shaft 41 in a swingable
manner.
[0059] The urging part 33 of the third holding unit 27 is combined
with the link mechanism constituted by the support part 32, the
first link 34 and the second link 35 of the third holding unit 27
to urge the second link 35 and the support part 32 in such a manner
that the contact part 31 of the third holding unit 27 is distanced
from the contact part 31 of the fourth holding unit 28. Further,
the urging part 33 of the fourth holding unit 28 is combined with
the link mechanism constituted by the support part 32, the first
link 34 and the second link 35 of the fourth holding unit 28 to
urge the second link 35 and the support part 32 in such a manner
that the contact part 31 of the fourth holding unit 28 is distanced
from the contact part 31 of the third holding unit 27.
[0060] As described above, when the first press drive member 23
presses the first holding unit 25 and the second holding unit 26
against the front wall portion 102, the support part 32 and the
contact part 31 of the first holding unit 25 swing against the
urging force of the urging part 33 of the first holding unit 25 in
such a manner that the contact part 31 of the first holding unit 25
approaches the contact part 31 of the second holding unit 26.
Specifically, when the first press drive member 23 presses the
first holding unit 25 against the front wall portion 102, the
contact part 31 of the first holding unit 25 swings against the
urging force of the urging part 33 of the first holding unit 25
while contacting the front wall portion 102 and thereby bends the
front wall portion 102. In addition, when the first press drive
member 23 presses the first holding unit 25 and the second holding
unit 26 against the front wall portion 102, the support part 32 and
the contact part 31 of the second holding unit 26 swing against the
urging force of the urging part 33 of the second holding unit 26 in
such a manner that the contact part 31 of the second holding unit
26 approaches the contact part 31 of the first holding unit 25. In
this way, when the first press drive member 23 presses the second
holding unit 26 against the front wall portion 102, the contact
part 31 of the second holding unit 26 swings against the urging
force of the urging part 33 of the second holding unit 26 and
thereby bends the front wall portion 102. As described above, when
the first press drive member 23 presses the first holding unit 25
and the second holding unit 26 against the front wall portion 102,
at least one of the contact part 31 of the first holding unit 25
and the contact part 31 of the second holding unit 26 is swung in
such a manner that the distance between the contact part 31 of the
first holding unit 25 and the contact part 31 of the second holding
unit 26 is made smaller, and thereby the front wall portion 102 is
bent and a gap can be created in the mouth portion 101.
[0061] In particular, in the present embodiment, in a situation
where the contact part 31 of the first holding unit 25 and the
contact part 31 of the third holding unit 27 are opposed to each
other via the front wall portion 102 and the back wall portion 103
of the bag body 100 while the contact part 31 of the second holding
unit 26 and the contact part 31 of the fourth holding unit 28 are
opposed to each other via the front wall portion 102 and the back
wall portion 103 of the bag body 100, the first press drive member
23 presses the first holding unit 25 and the second holding unit 26
against the front wall portion 102, and the second press drive
member 24 presses the third holding unit 27 and the fourth holding
unit 28 against the back wall portion 103. Thus, the first holding
unit 25 (for example, the contact part 31, the support part 32 and
the second link 35) and the third holding unit 27 (for example, the
contact part 31, the support part 32 and the second link 35) behave
in a symmetric fashion with respect to the bag body 100, and the
second holding unit 26 and the fourth holding unit 28 also behave
in a symmetric fashion with respect to the bag body 100.
[0062] Meanwhile, the air blowing unit 12 is installed above the
mouth portion 101 of a bag body 100 with respect to the vertical
direction, and the ejection port 45 of the air blowing unit 12 is
directed towards the mouth portion 101 of the bag body 100. The air
blowing unit 12 is connected to an air supply source (not shown),
and compresses the air from the air supply source and ejects the
compressed air from the ejection port 45. Although the illustrated
air blowing unit 12 has the ejection port 45 in the form of a
nozzle, the air blowing unit 12 and the ejection port 45 may take
any form capable of appropriately ejecting compressed air.
[0063] Typically, the ejection port 45 of the air blowing unit 12
is disposed above the center position of the mouth portion 101 of a
bag body 100; however, the relative arrangement position and
direction of the ejection port 45 with respect to the mouth portion
101 of a bag body 100 are not limited. For example, the ejection
port 45 of the air blowing unit 12 may be oriented so as to eject
compressed air in an oblique direction with respect to the mouth
portion 101 of a bag body 100. Further, the ejection port 45 of the
air blowing unit 12 may be oriented so as to eject compressed air
toward a position of the mouth portion 101 of a bag body 100 other
than the center position.
[0064] Next, a bag opening method according to which a gap is
formed between the front wall portion 102 and the back wall portion
103 of a bag body 100 and the bag body 100 is opened will be
described.
[0065] A bag opening method performed by using the above-described
bag opening apparatus 10 includes: a step of bending both the front
wall portion 102 and the back wall portion 103 to form a gap
between the front wall portion 102 and the back wall portion 103;
and a step of blowing compressed air from the air blowing unit 12
into the gap formed in the bag mouth to spread the inside of the
bag body 100 with the compressed air.
[0066] FIGS. 2 to 4 are process diagrams of a bag opening method
according to the first embodiment.
[0067] First, as shown in FIG. 2, the first opening unit 21 (the
first press drive member 23, the first holding unit 25 and the
second holding unit 26) and the second opening unit 22 (the second
press drive member 24, the third holding unit 27 and the fourth
holding unit 28) are arranged at positions separated from a bag
body 100 gripped by a pair of grippers 110.
[0068] Then, as shown in FIG. 3, the first opening unit 21 and the
second opening unit 22 are moved to approach each other in such a
manner that the contact parts 31 of the first holding unit 25 to
the fourth holding unit 28 are brought into contact with the bag
body 100. As a result, the contact part 31 of the first holding
unit 25 and the contact part 31 of the third holding unit 27 are
opposed to each other with the bag body 100 interposed
therebetween, and the contact part 31 of the second holding unit 26
and the contact part 31 of the fourth holding unit 28 are opposed
to each other with the bag body 100 interposed therebetween.
[0069] The contact timing of the first holding unit 25 to the
fourth holding unit 28 with respect to the bag body 100 is not
limited. All of the first holding unit 25 to the fourth holding
unit 28 may be brought into contact with the bag body 100 at almost
the same time, or one of the set of the first holding unit 25 and
the second holding unit 26 (that is, the first opening unit 21) and
the set of the third holding unit 27 and the fourth holding unit 28
(that is, the second opening unit 22) may come into contact with
the bag body 100 prior to the other.
[0070] Then, as shown in FIG. 4, both the first opening unit 21 and
the second opening unit 22 are further moved toward the bag body
100, so that the front wall portion 102 and the back wall portion
103 of the bag body 100 are bent. Specifically, the first press
drive member 23 presses the first holding unit 25 and the second
holding unit 26 against the front wall portion 102 to force the
support part 32 of the first holding unit 25 to swing against the
urging force of the urging part 33 of the first holding unit 25 and
to force the support part 32 of the second holding unit 26 to swing
against the urging force of the urging part 33 of the second
holding unit 26 in such a manner that the contact part 31 of the
first holding unit 25 and the contact part 31 of the second holding
unit 26 approach each other. Similarly, the second press drive
member 24 presses the third holding unit 27 and the fourth holding
unit 28 against the back wall portion 103 to force the support part
32 of the third holding unit 27 to swing against the urging force
of the urging part 33 of the third holding unit 27 and to force the
support part 32 of the fourth holding unit 28 to swing against the
urging force of the urging part 33 of the fourth holding unit 28 in
such a manner that the contact part 31 of the third holding unit 27
and the contact part 31 of the fourth holding unit 28 approach each
other.
[0071] In this way, the contact parts 31 of the first holding unit
25 to the fourth holding unit 28 are moved inward in the width
direction of the bag body 100 in a state of contacting the bag
surfaces of the bag body 100, so that the front wall portion 102
and the back wall portion 103 of the bag body 100 are displaced
inward in the width direction. As a result, a gap is formed in the
mouth portion 101 and the bag body 100 is opened. In this
situation, the grippers 110 forming a pair are moved to approach
each other while the grippers 110 grip both side portions
(particularly both side edge portions) of the bag body 100, so that
the front wall portion 102 and the back wall portion 103 are
loosened to the extent that a gap can be formed in the mouth
portion 101. It is preferable that this approaching movement of the
pair of grippers 110 be carried out after the contact parts 31 of
the first holding unit 25 to the fourth holding unit 28 have
contacted the bag body 100 (see FIG. 3). Further, it is preferable
that the approaching movement of the pair of grippers 110 be
carried out before the contact part 31 of the first holding unit 25
and the contact part 31 of the second holding unit 26 come close to
each other and before the contact part 31 of the third holding unit
27 and the contact part 31 of fourth holding unit 28 come close to
each other. Alternatively, it is preferable that the approaching
movement of the pair of grippers 110 be carried out simultaneously
with the time when the contact part 31 of the first holding unit 25
and the contact part 31 of the second holding unit 26 come close to
each other and simultaneously with the contact part 31 of the third
holding unit 27 and the contact part 31 of fourth holding unit 28
come close to each other.
[0072] As described above, before or during swinging of the contact
part 31 of the first holding unit 25 by the first press drive
member 23 pressing the first holding unit 25 against the front wall
portion 102, at least one of the grippers 110 forming a pair (both
the grippers 110 in the present embodiment) is moved in such a
manner that the distance between the grippers 110 forming a pair
becomes smaller.
[0073] Then, compressed air is blown from the air blowing unit 12
(see FIG. 1) toward the gap in the mouth portion 101 of the bag
body 100, although the illustration in the drawings is omitted. As
a result, the compressed air is supplied to the interior of the bag
body 100, which enables the inside of the bag body 100 to spread up
to the bag bottom.
[0074] As described above, according to the bag opening apparatus
10 and the bag opening method of the present embodiment, negative
pressure suction using a suction cup or the like is not used in the
opening process of a bag body 100. Thus, the period of time for
forming a negative pressure is not required, the period of time for
the opening process can be shortened, and the processing can be
performed at high speed.
[0075] In general, a bag opening method using suction cups
requires: (1) a step of pressing the suction cups against the front
surface and the back surface of a bag body respectively; (2) a step
of performing deairing and forming a negative pressure between each
suction cup and the bag surface; (3) a step of measuring the
pressure between the suction cup and the bag surface after elapse
of a predetermined time from the start of the deairing; (4) a step
of distancing the suction cups from each other to form a gap in the
mouth portion; and (5) a step of blowing compressed air toward the
gap. In particular, the above-mentioned "(2) a step for forming a
negative pressure" requires a decent period of time, and if a
decent time is not secured for "(2) a step for forming a negative
pressure", it is not possible for each suction cup to adequately
suck the bag surface and thus the bag body cannot be properly
opened.
[0076] In contrast, the bag opening method according to the present
embodiment includes: (a) a step of bringing the first holding unit
25 to the fourth holding unit 28 into contact with a bag body 100;
(b) a step of pressing the first holding unit 25 to the fourth
holding unit 28 against the bag body 100 to form a gap in the mouth
portion 101; and (c) a step of blowing compressed air into the gap.
As described above, according to the above-described embodiment, a
step itself of forming a negative pressure is unnecessary, and a
gap can be appropriately created in the mouth portion 101 of a bag
body 100 by just the actions of pressing the first holding unit 25
to the fourth holding unit 28 against a bag body 100.
[0077] In particular, by moving a pair of holding units (that is,
"a set of the first holding unit 25 and the second holding unit 26"
or "a set of the third holding unit 27 and the fourth holding unit
28") toward a bag body 100, it is possible not only to bring the
contact parts 31 of the pair of holding units into contact with the
bag body 100 but also to move the pair of contact parts 31 inward
in the width direction of the bag body 100. Specifically, the first
holding unit 25 to the fourth holding unit 28 of the present
embodiment can be moved inward in the width direction almost
simultaneously with the contact with a bag body 100 so that the
front wall portion 102 and the back wall portion 103 of the bag
body 100 are bent. As described above, "(a) the step of bringing
the first holding unit 25 to the fourth holding unit 28 into
contact with a bag body 100" and "(b) a step of forming a gap in
the mouth portion 101" can be performed in a sequential processing
in which the first opening unit 21 and the second opening unit 22
are moved toward a bag body 100, and therefore it is possible to
form a gap in the mouth portion 101 very efficiently in a short
time.
[0078] By forming a gap in the mouth portion 101 of a bag body 100
in a short time in this way, "(c) a step of blowing compressed air
into the gap" performed subsequently can be expedited. As a result,
it is possible to allocate a sufficient time to "(c) a step of
blowing compressed air into the gap" and thereby open a bag body
100 more reliably with compressed air. Further, it is also possible
to shorten the period of time required for the entire opening
process including the above (a) to (c) steps.
[0079] Incidentally, when the inventors measured the period of time
required for the above-described series of steps (that is, the
above-mentioned (a) to (c) steps) using the bag opening apparatus
10 according to the above-described first embodiment, it took
approximately 0.15 seconds for one bag body 100. In contrast, when
the inventors measured the period of time required for the
above-described series of steps (that is, the above-mentioned (1)
to (5) steps) using a conventional apparatus with suction cups, it
took approximately 0.5 seconds for one bag body 100. As described
above, according to the bag opening apparatus 10 of the present
embodiment, it is possible to perform the opening process of a bag
body 100 at least approximately three times faster than the
conventional apparatus.
[0080] Further, in the bag opening apparatus 10 of the present
embodiment, a negative pressure forming means, such as a vacuum
pump, is unnecessary, and there is no need to control such a
negative pressure forming means. In particular, in a conventional
apparatus using suction cups, a common negative pressure forming
means, such as a pump, is typically connected to a plurality of
suction cups in many cases, and in such a conventional apparatus,
there is concern that a problem occurring in one suction cup may
affect another suction cup. In contrast, in the bag opening
apparatus 10 of the present embodiment, there is no concern of such
propagation of problem.
[0081] In the present embodiment, the opening process of a bag body
100 is performed by combining a step of moving the first opening
unit 21 (in particular, the first press drive member 23) and the
second opening unit 22 (in particular, the second press drive
member 24), a step of moving the pair of grippers 110, and a step
of blowing air from the air blowing unit 12. The driving of these
elements may be controlled by a control unit (not shown) according
to the driving state of one another, or may be performed based on
predetermined timing. For example, the control unit may monitor the
movement amounts and the arrangement positions of the first press
drive member 23 and the second press drive member 24, and may move
the grippers 110 or may cause the air blowing unit 12 to eject
compressed air according to these movement amounts and arrangement
positions. Further, the time when the movement of the first press
drive member 23 and the second press drive member 24 is performed,
the time when the movement of the grippers 110 is performed, and
the time when the air ejection of the air blowing unit 12 is
performed, may be determined in advance within the time period when
a bag body 100 is intermittently stopped and stays at the opening
station S1. Further, the movement of the first press drive member
23 and the second press drive member 24, the movement of the
grippers 110, and the air ejection of the air blowing unit 12 may
be performed by combining the control based on the drive states and
the driving based on the time determined in advance.
Second Embodiment
[0082] In a bag opening apparatus 10 of the present embodiment,
elements which are the same as or similar to those of the
above-described bag opening apparatus 10 of the first embodiment
are denoted by the same reference numerals, and the detailed
description thereof will be omitted.
[0083] FIG. 5 is a plan view illustrating an example of a state of
a bag body 100 which may occur in the apparatus and the method
according to the first embodiment. According to the bag opening
apparatus 10 and the bag opening method according to the
above-described first embodiment, when the front wall portion 102
and the back wall portion 103 of a bag body 100 bend in mutually
different directions in terms of the X direction as shown in FIG.
4, a desired gap can be formed in the mouth portion 101 of the bag
body 100. On the other hand, when the front wall portion 102 and
the back wall portion 103 of a bag body 100 bend in the same
direction with respect to the X direction as shown in FIG. 5, a
desired gap is not formed in the mouth portion 101 of the bag body
100.
[0084] A bag opening apparatus 10 and a bag opening method
according to the present embodiment can effectively avoid the
trouble shown in FIG. 5, and can form a gap between the front wall
portion 102 and the back wall portion 103 more reliably so that the
bag body 100 can be properly opened.
[0085] FIG. 6 is a plan view Illustrating a schematic configuration
of a bag opening apparatus 10 according to the second
embodiment.
[0086] In the bag opening apparatus 10 according to the present
embodiment, the first opening unit 21 has almost the same
configuration as that of the above-described first embodiment, but
the second opening unit 22 has a receiving part 50 instead of the
third holding unit 27 and the fourth holding unit 28. Specifically,
the gap formation unit 11 according to the present embodiment
includes a receiving part 50 (i.e., a receiving plate in the
Illustrated example) disposed on the back wall portion 103 side,
and the receiving part 50 has a receiving surface 51. The receiving
surface 51 extends in parallel with the extension direction (that
is, the Y direction) of the back wall portion 103 of a bag body 100
gripped by a pair of grippers 110, and is disposed above the
grippers 110 with respect to the vertical direction. The receiving
part 50 includes an elastic member 52 (first elastic member) that
forms the receiving surface 51, and the elastic member 52 is
typically silicone or urethane.
[0087] The second press drive member 24 to which the receiving part
50 is attached can be moved in the same manner as in the
above-described first embodiment, and can advance and retreat the
receiving surface 51 of the receiving part 50 with respect to the
bag body 100 (in particular, the back wall portion 103). While the
second press drive member 24 of the present embodiment brings the
receiving surface 51 of the receiving part 50 into contact with the
back wall portion 103 of the bag body 100, the second press drive
member 24 basically does not press the receiving part 50 (receiving
surface 51) against the back wall portion 103. The receiving
surface 51 of the receiving part 50 acts as a pressing surface for
the first holding unit 25 and the second holding unit 26 when the
first holding unit 25 and the second holding unit 26 are caused to
be swung. When the first holding unit 25 and the second holding
unit 26 are pressed against the front wall portion 102 of a bag
body 100, the receiving surface 51 is fixedly arranged, and pushes
back the first holding unit 25 and the second holding unit 26 while
supporting the back wall portion 103. As a result, when the first
holding unit 25 and the second holding unit 26 are pressed against
the front wall portion 102 of a bag body 100, the back wall portion
103 of the bag body 100 is held on the receiving surface 51 and
basically keeps its almost planar state at the same position, and
only the front wall portion 102 is bent by the first holding unit
25 and the second holding unit 26. However, the second press drive
member 24 may press the receiving part 50 (receiving surface 51)
against the back wall portion 103. In this case, the back wall
portion 103 may be tensioned by the force received from the
receiving surface 51 of the receiving part 50 while an excessive
load is not applied to the bag body 100 (in particular, the back
wall portion 103) from the receiving surface 51 of the receiving
part 50 and the flat state of the back wall portion 103 along the
receiving surface 51 is maintained.
[0088] The other configuration is almost the same as that of the
above-described first embodiment.
[0089] The bag opening method using the bag opening apparatus 10 of
the present embodiment described above includes: a step of bending
the front wall portion 102 of a bag body 100 to form a gap between
the front wall portion 102 and the back wall portion 103; and a
step of blowing compressed air from the air blowing unit 12 toward
the gap formed in the bag mouth to spread the interior of the bag
body 100 with the compressed air. The back wall portion 103 of the
bag body 100 is supported by the receiving surface 51 of the
receiving part 50 and basically maintains a state of extending
linearly in the Y direction.
[0090] FIGS. 7 to 9 are process diagrams of a bag opening method
according to the second embodiment, showing states in which the bag
opening apparatus is viewed from above. FIGS. 10 to 13 are process
diagrams of the bag opening method according to the second
embodiment, showing states in which the bag opening apparatus is
viewed from the side. In FIGS. 10 to 13, the arrow marked with "Z"
corresponds to the vertical direction.
[0091] First, as shown in FIGS. 7 and 10, the first opening unit 21
(the first press drive member 23, the first holding unit 25 and the
second holding unit 26) and the second opening unit 22 (the second
press drive member 24 and the receiving part 50) are arranged at
positions separated from a bag body 100 gripped by a pair of
grippers 110 in the horizontal direction (in particular, the X
direction).
[0092] Then, as shown in FIGS. 8 and 11, the first opening unit 21
and the second opening unit 22 are moved to approach each other in
such a manner that the first holding unit 25 and the second holding
unit 26 are brought into contact with the front wall portion 102 of
the bag body 100 and the receiving surface 51 of the receiving part
50 is brought into contact with the back wall portion 103 of the
bag body 100. As a result, the first holding unit 25 and the second
holding unit 26 are opposed to the receiving surface 51 of the
receiving part 50 via the bag body 100.
[0093] The contact timing of the first holding unit 25, the second
holding unit 26 and the receiving surface 51 of the receiving part
50 with respect to the bag body 100 is not limited. All of the
first holding unit 25, the second holding unit 26 and the receiving
part 50 may be brought into contact with the bag body 100 at almost
the same time, or one of the receiving part 50 (that is, the second
opening unit 22) and a set of the first holding unit 25 and the
second holding unit 26 (that is, the first opening unit 21) may
come into contact with the bag body 100 prior to the other. For
example, by bringing the receiving part 50 into contact with the
bag body 100 (specifically, the back wall portion 103) prior to the
first holding unit 25 and the second holding unit 26, the first
holding unit 25 and the second holding unit 26 can subsequently
perform the contact operation and the pressing operation with
respect to the bag body 100 (specifically, the front wall portion
102) in a continuous manner without stopping.
[0094] Then, as shown in FIGS. 9 and 12, the first opening unit 21
is further moved toward the bag body 100 so that the front wall
portion 102 of the bag body 100 is bent. Specifically, the first
holding unit 25 and the second holding unit 26 are pressed against
the front wall portion 102 by the first press drive member 23, and
thereby the support part 32 of the first holding unit 25 is swung
against the urging force of the urging part 33 of the first holding
unit 25 and the support part 32 of the second holding unit 26 is
swung against the urging force of the urging part 33 of the second
holding unit 26 so that the contact part 31 of the first holding
unit 25 and the contact part 31 of the second holding unit 26
approach each other.
[0095] On the other hand, while the contact part 31 of the first
holding unit 25 and the contact part 31 of the second holding unit
26 approach each other, the receiving part 50 is stopped in a state
of being in contact with the back wall portion 103 of the bag body
100, and the back wall portion 103 is supported on the receiving
surface 51 of the receiving part 50 and is kept almost parallel to
the Y direction.
[0096] As described above, in a state where the front wall portion
102 and the back wall portion 103 are sandwiched between the
receiving surface 51 and each of the first holding unit 25 and the
second holding unit 26, the first press drive member 23 further
presses the first holding unit 25 and the second holding unit 26
against the front wall portion 102. As a result, the first holding
unit 25 and the second holding unit 26 move inward in the width
direction of the bag body 100 while being pressed against the front
wall portion 102 of the bag body 100. In this way, by moving the
contact part 31 of the first holding unit 25 and the contact part
31 of the second holding unit 26 placed in contact with the front
wall portion 102 inward in the width direction of the bag body 100,
the front wall portion 102 of the bag body 100 is displaced inward
in the width direction. As a result, a gap is formed in the mouth
portion 101 of the bag body 100.
[0097] Then, as shown in FIG. 13, compressed air is blown from the
air blowing unit 12 toward the gap in the mouth portion 101 of the
bag body 100. As a result, the compressed air enters into the bag
body 100, enabling the inside of the bag body 100 to spread to the
bag bottom.
[0098] As described above, according to the bag opening apparatus
10 and the bag opening method of the present embodiment, a bag body
100 can be opened. In particular, since the opening process of a
bag body 100 is performed in a state where the back wall portion
103 of the bag body 100 is supported by the receiving part 50, the
problem that the front wall portion 102 and the back wall portion
103 of the bag body 100 are bent in the same direction as each
other (see FIG. 5) can be effectively avoided.
MODIFIED EXAMPLES
[0099] The present invention is not limited to the above-described
embodiments and modified examples. For example, various
modifications may be made to each element of the embodiments and
the modified examples described above.
First Modified Example
[0100] FIG. 14 is a plan view illustrating a schematic
configuration of a bag opening apparatus 10 according to a first
modified example.
[0101] In the first holding unit 25 to the fourth holding unit 28
of the above-described embodiments, the first link 34 is fixedly
provided with respect to the first press drive member 23 or the
second press drive member 24; however, the first link 34 may be
provided so as to be capable of swinging with respect to the first
press drive member 23 or the second press drive member 24.
[0102] The first links 34 of the first holding unit 25 and the
second holding unit 26 according to the present modified example
shown in FIG. 14 each have an end on one side connected swingably
to the first press drive member 23 via the third support shaft 43,
and each have an end on the other side connected swingably to one
side of the support part 32 via the second support shaft 42. The
other configuration is almost the same as that of the bag opening
apparatus 10 of the above-described second embodiment.
[0103] In this modified example, the first link 34, the second link
35 and the support part 32 of each of the first holding unit 25 and
the second holding unit 26 constitute a link mechanism. The urging
part 33 of the first holding unit 25 is combined with this link
mechanism to urge the support part 32 and the second link 35 of the
first holding unit 25 in such a manner that the contact part 31 of
the first holding unit 25 is distanced from the contact part 31 of
the second holding unit 26. Further, the urging part 33 of the
second holding unit 26 is combined with this link mechanism to urge
the support part 32 and the second link 35 of the second holding
unit 26 in such a manner that the contact part 31 of the second
holding unit 26 is distanced from the contact part 31 of the first
holding unit 25. Thus, by causing the first press drive member 23
to press the contact part 31 of the first holding unit 25 and the
contact part 31 of the second holding unit 26 against the front
wall portion 102 of a bag body in a state in which the back wall
portion 103 of the bag body 100 is supported by the receiving
surface 51 of the receiving part 50, the front wall portion 102 can
be bent to form a gap in the mouth portion 101.
[0104] While FIG. 14 shows an example in which a first link 34
provided swingably is applied to the above-described second
embodiment, this first link 34 may be applied to the
above-described first embodiment. Specifically, not only in the
first holding unit 25 and the second holding unit 26 but also in
the third holding unit 27 and the fourth holding unit 28, the end
of one side of a first link 34 may be swingably attached to the
second press drive member 24 via the third support shaft 43, and
the end of the other side of the first link 34 is swingably
attached to one side of the support part 32 via the second support
shaft 42.
Other Modified Examples
[0105] For example, the bag opening apparatus 10 may
supplementarily utilize a suction cup. As a specific example, a
suction cup is provided between the first holding unit 25 and the
second holding unit 26, and when the front wall portion 102 of a
bag body 100 is bent by the first holding unit 25 and the second
holding unit 26, the front wall portion 102 may be sucked by the
suction cup. In this case, by moving the suction cup, the front
wall portion 102 can be moved to open the bag body 100. In this
way, it is possible to open a bag body 100 without blowing air into
the mouth portion 101 of the bag body 100, and therefore, the
above-described air blowing unit 12 may not be provided.
[0106] Further, in the embodiments and the modified examples
described above, when the first holding unit 25 and the second
holding unit 26 are pressed against the front wall portion 102 of a
bag body 100, both the contact part 31 of the first holding unit 25
and the contact part 31 of the second holding unit 26 are moved in
the Y direction (that is, the extension direction of the bag body
100); however, only one of the contact parts 31 of the first
holding unit 25 and the second holding unit 26 may be moved in the
Y direction. Similarly, when the third holding unit 27 and the
fourth holding unit 28 are pressed against the back wall portion
103 of a bag body 100, only one of the contact parts 31 of the
third holding unit 27 and the fourth holding unit 28 may be moved
in the Y direction.
[0107] Further, in the bag opening apparatus 10 of the second
embodiment shown in FIGS. 6 to 13, the receiving surface 51 of the
receiving part 50 may have any structure capable of appropriately
supporting the back wall portion 103 of a bag body 100. For
example, one or more of suction holes may be formed in the
receiving surface 51, and in a state in which the back wall portion
103 of a bag body 100 is in contact with the receiving surface 51
of the receiving part 50, the suction may be performed through the
one or more of suction holes. In this case, the back wall portion
103 of a bag body 100 can be sucked by the receiving part 50, and
the back wall portion 103 can be effectively prevented from
deflecting when the front wall portion 102 of the bag body 100 is
bent by the first holding unit 25 and the second holding unit
26.
[0108] Further, in the above-described embodiments and modified
examples, a case where a bag body 100 is intermittently transferred
with grippers 110 and the bag body 100 is opened by the bag opening
apparatus 10 while the bag body 100 is stopped is described, but
the bag opening apparatus 10 may open a bag body 100 which is in a
moving state. For example, by configuring the bag opening apparatus
10 to be movable and by providing the bag opening apparatus 10 so
as to follow a moving bag body 100 in a part of the transfer path
of the bag body 100, it is possible for the bag opening apparatus
10 to open the bag body 100 without stopping the bag body 100.
Therefore, bag opening apparatuses and bag opening methods
according to the present invention can be applied not only to
apparatuses adopting an intermittent transport system as described
above but also to apparatuses which continuously transport a bag
body 100 without Intermittently stopping the bag body 100. Further,
it is possible that, in an intermittent transfer type apparatus, a
bag body 100 is opened by the bag opening apparatus 10 while the
bag body 100 is intermittently moving.
[0109] The embodiments of the present invention include embodiments
which each include a constituent element and/or a method other than
the above-described constituent elements and/or methods. Also,
embodiments in which some of the above-described constituent
elements and/or methods are not included may also be Included in
the embodiments of the present invention. Further, embodiments
which each include some constituent elements and/or methods
included in a certain embodiment of the present invention and some
constituent elements and/or methods included in another embodiment
of the present invention may also be included in the embodiments of
the present invention. Therefore, constituent elements and/or
methods included in the embodiments and modified examples described
above and embodiments of the present invention which are not
described above may be combined with one another, and an embodiment
based on such combination may also be Included in the embodiments
of the present invention. Further, the effects brought about by the
present invention are not limited to the above-described effects,
and particular effects depending on the specific configuration of
each embodiment can be exerted. As described above, various
additions, modifications and partial deletions may be made to each
element described in the claims, the description, the abstract and
the drawings without departing from the technical idea and gist of
the present invention.
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