U.S. patent application number 09/971795 was filed with the patent office on 2002-05-02 for bag opening apparatus and method for use in bag filling and packaging machine using flat bags.
This patent application is currently assigned to TOYO JIDOKI CO., LTD.. Invention is credited to Fukuda, Sumio, Hiramoto, Shinichi.
Application Number | 20020050304 09/971795 |
Document ID | / |
Family ID | 18804477 |
Filed Date | 2002-05-02 |
United States Patent
Application |
20020050304 |
Kind Code |
A1 |
Hiramoto, Shinichi ; et
al. |
May 2, 2002 |
Bag opening apparatus and method for use in bag filling and
packaging machine using flat bags
Abstract
A bag opening apparatus and method for use in a bag filling and
packaging machine using flat bags allow a bag to move to a
subsequent step while being surely maintained in the state of
having been opened. At a mouth opening step, the mouth portion of a
bag is opened by using suction cups serving as a mouth opening
device. Next, an abutting member of a bag bottom deforming device
is moved upward to abut on the bottom of the bag, thereby deforming
at least a part of the bottom inward of the bag, while restraining
movement of a lower portion of the bag with retaining plates of a
bag movement restraining device.
Inventors: |
Hiramoto, Shinichi;
(Iwakuni-shi, JP) ; Fukuda, Sumio; (Iwakuni-shi,
JP) |
Correspondence
Address: |
GALGANO & BURKE
Suite 135
300 Rabro Drive
Hauppauge
NY
11788
US
|
Assignee: |
TOYO JIDOKI CO., LTD.
|
Family ID: |
18804477 |
Appl. No.: |
09/971795 |
Filed: |
October 5, 2001 |
Current U.S.
Class: |
141/114 ;
53/384.1 |
Current CPC
Class: |
B65B 43/465
20130101 |
Class at
Publication: |
141/114 ;
53/384.1 |
International
Class: |
B65B 003/16 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 26, 2000 |
JP |
2000-327467 |
Claims
What is claimed is:
1. A bag opening apparatus for use in a bag filling and packaging
machine using a flat bag, said apparatus comprising: a mouth
opening device for opening a mouth portion of said bag; a bag
bottom deforming device for deforming at least a part of a bottom
of the bag inward of said bag whose mouth portion has been opened
by said mouth opening device; and a bag movement restraining device
for restraining movement of a portion of said bag in a vicinity of
the bottom of said bag in a direction approximately perpendicular
to a planar portion of said bag so that said movement is restricted
within predetermined limits.
2. A bag opening apparatus according to claim 1, wherein said bag
bottom deforming device includes: an abutting member for abutting
on the bottom of said bag to deform said bottom inward of said bag;
and an elevating-and-lowering device for vertically moving said
abutting member.
3. A bag opening apparatus according to claim 2, wherein said
abutting member is a rod-shaped member, said abutting member
abutting on the bottom of said bag at an approximately central
portion in a width direction of said bag to deform the bottom of
said bag.
4. A bag opening apparatus according to claims 1, wherein said bag
movement restraining device has retaining plates disposed at both
sides of said bag so as to face each other across said bag, said
retaining plates being capable of moving toward and away from each
other, said retaining plates having bag movement restraining
portions arranged such that when said retaining plates move toward
each other, said bag movement restraining portions face each other
across each side edge portion of said bag over a predetermined
height range from the bottom of said bag.
5. A bag opening apparatus according to claims 2, wherein said bag
movement restraining device has retaining plates disposed at both
sides of said bag so as to face each other across said bag, said
retaining plates being capable of moving toward and away from each
other, said retaining plates having bag movement restraining
portions arranged such that when said retaining plates move toward
each other, said bag movement restraining portions face each other
across each side edge portion of said bag over a predetermined
height range from the bottom of said bag.
6. A bag opening apparatus according to claims 3, wherein said bag
movement restraining device has retaining plates disposed at both
sides of said bag so as to face each other across said bag, said
retaining plates being capable of moving toward and away from each
other, said retaining plates having bag movement restraining
portions arranged such that when said retaining plates move toward
each other, said bag movement restraining portions face each other
across each side edge portion of said bag over a predetermined
height range from the bottom of said bag.
7. A bag opening method for use in a bag filling and packaging
machine using a flat bag, said method comprising the steps of:
opening a mouth of said bag; and deforming a bottom of said bag
inward of said bag.
8. A bag opening method according to claim 7, further comprising
the step of restraining a portion of said bag in a vicinity of the
bottom of said bag from moving in a direction approximately
perpendicular to a planar portion of said bag when the bottom of
said bag is deformed.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to an apparatus and method for
opening bags used in a bag filling and packaging machine. More
particularly, the present invention relates to a bag opening
apparatus and method for use in a bag filling and packaging machine
using flat bags as packaging bags. It should be noted that the term
"flat bags" as used herein includes the type that has a chuck at
the bag mouth portion.
[0003] 2. Discussion of Related Art
[0004] There is a conventional bag filling and packaging machine of
the type in which an operation of opening a bag and an operation of
filling the bag with a material to be packed are carried out at the
same step. With this type of packaging machine, however, the
processing time at each step becomes undesirably long. Therefore,
the operating speed of the packaging machine cannot be increased.
To cope with this problem, one type of conventional bag filling and
packaging machine adopts a method wherein a bag opening step and a
filling step are carried out separately from each other. That is, a
bag is opened at the bag opening step, and the bag thus opened is
moved to the filling step to fill it with a material to be
packed.
[0005] With the above-described method, however, some problems may
arise when flat bags are used. That is, the mouth of a flat bag is
opened by pulling the bag from both sides using suction cups, for
example, and in this state, air is sent into the bag from the mouth
to open the bag as far as the bottom thereof. The bag thus opened
may be undesirably closed during movement to the subsequent step,
i.e. filling step, by the action of air resistance applied to the
bag during the movement, or by the bag's own restoring force or the
like. A bag undesirably closed in this way may interfere with the
filling operation.
[0006] To solve the above-described problem, Japanese Patent No.
2981952 discloses an apparatus having a driving arm adapted to
reciprocate between a bag opening step and a filling step. The
apparatus further has an opening and closing arm secured to the
driving arm and a mouth opening claw attached to the opening and
closing arm. The opening and closing arm and the mouth opening claw
are opened and closed by using a cam and a cam follower. At the bag
opening step, the driving arm is moved downward to insert the
closed mouth opening claw into a bag having its mouth opened with
suction cups. When the bag is moved to the filling step, the cam
follower separates from the cam, thereby expanding the opening and
closing arm to open the bag as far as the bottom thereof. In this
state, the driving arm is moved to the filling step, together with
the bag. After a filling hopper has been inserted into the mouth of
the bag, the driving arm is moved upward so as to be removed from
the bag. Thereafter, the driving arm is returned to the bag opening
step, and the cam follower is brought into abutting contact with
the cam to close the mouth opening claw.
[0007] With the arrangement of the above-described apparatus, the
bag is transferred from the bag opening step to the filling step
while being maintained in the open state by the mouth opening claw.
Therefore, the problem that the bag is undesirably closed will not
occur.
[0008] However, in the bag opening apparatus that moves in such a
manner as to follow the movement of the bag from the bag opening
step to the filling step, it is necessary to return the driving arm
from the filling step to the bag opening step in order to open the
subsequent bag. Therefore, the apparatus requires time for
returning the driving arm. This limits the achievement of an
increase in the operating speed of the packaging machine. Further,
the apparatus itself becomes complicated and costly. In addition,
the operating efficiency lowers in maintenance or a cleaning
operation.
SUMMARY OF THE INVENTION
[0009] The present invention was made in view of the
above-described problems associated with the prior art.
[0010] Accordingly, an object of the present invention is to
provide a bag opening apparatus and method for flat bags that is
capable of moving a bag opened at a bag opening step to a filling
step while surely maintaining the bag in the state of being open
and also capable of attaining an increase in the operating speed of
packaging machines.
[0011] Another object of the present invention is to provide a bag
opening apparatus and method for flat bags that is simple in
arrangement and capable of being provided at low costs and that is
excellent in operating efficiency in maintenance and so forth.
[0012] To attain the above-described problems, the present
invention provides a bag opening apparatus including a mouth
opening device for opening a mouth portion of a bag. The apparatus
further includes a bag bottom deforming device for deforming at
least a part of the bottom of the bag inward of the bag whose mouth
portion has been opened by the mouth opening device. Further, the
apparatus includes a bag movement restraining device for
restraining movement of a portion of the bag in the vicinity of the
bottom thereof, particularly the movement of that portion in a
direction approximately perpendicular to a planar portion of the
bag, so that the movement is restricted within predetermined
limits.
[0013] The bag bottom deforming device may include an abutting
member for abutting on the bottom of the bag to deform the bottom
inward of the bag and an elevating-and-lowering device for
vertically moving the abutting member. More specifically, the
abutting member may be a rod-shaped member. The abutting member is
brought into abutting contact with the bottom of the bag at an
approximately central portion in the width direction of the bag and
moved upward by the elevating-and-lowering device to deform the
bottom of the bag.
[0014] More specifically, the bag movement restraining device may
be formed from retaining plates disposed at both sides of the bag
so as to face each other across the bag. The retaining plates are
capable of moving toward and away from each other. The retaining
plates have bag movement restraining portions arranged such that
when the retaining plates move toward each other, the bag movement
restraining portions face each other across each side edge portion
of the bag over a predetermined height range from the bottom of the
bag.
[0015] In addition, the present invention provides a bag opening
method including the step of opening the mouth of a bag and the
step of deforming the bottom of the bag inward of the bag. The
method may further include the step of restraining a portion of the
bag in the vicinity of the bottom thereof from moving in a
direction approximately perpendicular to a planar portion of the
bag when the bottom of the bag is deformed.
[0016] Other objects and advantages of the present invention will
become apparent from the following detailed description of
illustrated embodiments of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 is a side view showing the arrangement of a bag
opening apparatus according to an embodiment of the present
invention, which also shows an air inflating device
schematically.
[0018] FIGS. 2a to 2e are front views showing a bag opening
operation performed with the bag opening apparatus shown in FIG.
1.
[0019] FIGS. 3a to 3e are side views showing the bag opening
operation.
[0020] FIGS. 4a to 4d are plan views showing the bag opening
operation.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0021] Specific embodiments of the present invention will be
described below with reference to the accompanying drawings. FIG. 1
is a side view showing the arrangement of a bag opening apparatus
10 used at a bag opening step. FIGS. 2a to 4d are front, side and
plan views showing a bag opening operation performed by using the
bag opening apparatus 10.
[0022] In the figures, reference numeral 1 denotes a bag known as
"flat bag", which is used for bag filling and packaging. The bag 1
is gripped with a pair of grippers 2a and 2b serving as one of
gripping devices provided at predetermined spaces on a rotary table
(not shown) of a packaging machine. More specifically, the bag 1 is
gripped with the grippers 2a and 2b at both side edges lb and lc
slightly below a bag mouth portion la (see FIG. 2a). In this state,
the bag 1 moves through various bag filling and packaging steps
successively as the table rotates. Publicly known gripping devices
are usable as the grippers 2a and 2b. Therefore, a description
thereof is omitted. In FIG. 1, the bag 1 moves to the illustrated
position from the preceding step provided at the front or back side
of the plane of the figure and stops there for a predetermined
period of time.
[0023] The bag opening apparatus 10 in this embodiment has a bag
mouth opening device 12 for opening the bag mouth portion 1a. The
bag mouth opening device 12 has a pair of suction cups 12a and 12b
connected to a vacuum source (not shown). The suction cups 12a and
12b are positioned to face both sides of the bag 1, which is
gripped with the grippers 2a and 2b, in the vicinity of the bag
mouth portion la at an approximately central position in the width
direction of the bag 1. The suction cups 12a and 12b stick to the
bag 1 by vacuum from both sides and then retract to thereby open
the bag mouth portion 1a. This bag mouth opening device 12 is
publicly known. Therefore, a detailed description thereof is
omitted.
[0024] An inflating device 16 is positioned so as to lie above the
bag 1 to blow air into the bag 1 from the mouth portion 1a that is
held open, thereby opening the bag 1 as far as a bottom 1d thereof.
The inflating device 16 has an elevating shaft 18 that is moved
vertically by a drive source (not shown) . An arm 20 is secured to
the elevating shaft 18 to extend sideward. An air nozzle 22 is
supported by the arm 20 in such a manner that an air outlet 24
faces downward at the lower end of the nozzle 22. An air inlet 26
of the nozzle 22 is connected to a compressed air source (not
shown). This type of inflating device 16 is publicly known.
Therefore, a further detailed description thereof is omitted.
[0025] The bag opening apparatus 10 according to this embodiment
has a bag bottom deforming device 28 and a bag movement restraining
device 40 in addition to the above-described bag mouth opening
device 12 and inflating device 16. The bag bottom deforming device
28 deforms the bottom 1d of the bag 1 as described later. The bag
bottom deforming device 28 has an air cylinder 30 installed on the
base frame (not shown) of the packaging machine. The air cylinder
30 has a cylinder rod 32 adapted to extend or contract in response
to the operation of the air cylinder 30. A bag bottom abutting
member 34 is secured to the distal end of the cylinder rod 32 to
extend sideward. In this embodiment, the abutting member 34 is a
rod member having a circular sectional configuration. As shown in
FIGS. 1 to 3e, the abutting member 34 extends under the bottom 1d
of the bag 1 at an approximately central portion in the lateral
direction of the bag 1 gripped with the grippers 2a and 2b, at an
approximately right angle to a plane in which a planar portion 1e
of the bag 1 extends. When the rod 32 moves upward, the abutting
member 34 comes in abutting contact with the bottom 1d of the bag 1
and pushes it up, thereby deforming the bottom 1d as described
later.
[0026] The bag movement restraining device 40 restrains movement of
at least a part of the bag 1 in the vicinity of the bottom 1d,
particularly the movement thereof in a direction approximately
perpendicular to the planar portion 1e of the bag 1, when the bag
bottom deforming device 28 performs the operation of deforming the
bottom 1d of the bag 1. More specifically, when the bottom 1d of
the bag 1 is pushed up with the abutting member 34, the bag
movement restraining device 40 prevents the bottom 1d of the bag 1
from moving along the abutting member 34 in the longitudinal
direction of the abutting member 34.
[0027] The bag movement restraining device 40 has a pair of opening
and closing arms 42 and 44 pivotably supported by a pivot shaft 46
secured to the base frame (not shown). The opening and closing arms
42 and 44 respectively have upper portions 42a and 44a above the
pivot shaft 46 and lower portions 42b and 44b below the pivot shaft
46. The opening and closing arms 42 and 44 are arranged to
intersect each other at the pivot shaft 46 in an approximately
X-shaped configuration.
[0028] The opening and closing arms 42 and 44 have rollers 48 and
50 rotatably attached to the lower ends of the lower portions 42b
and 44b. A tension spring 51 is provided between predetermined
positions of the lower portions 42b and 44b, as shown in FIG. 1, to
urge the opening and closing arms 42 and 44 in respective
directions in which the rollers 48 and 50 come toward each other.
Below the opening and closing arms 42 and 44, an opening and
closing cam 52 having an approximately triangular pyramid-like
shape is placed with its vertex side facing upward. The opening and
closing cam 52 is secured to the distal end of a cam elevating
shaft 56 driven to move vertically through a predetermined distance
by a driving device (not shown). FIG. 1 shows the bag movement
restraining device 40 in a state where the opening and closing cam
52 is in a lowered position. In this state, a guide member 54
secured to the distal end of the cam 52 is located between the
rollers 48 and 50 to separate the rollers 48 and 50 from each other
by a predetermined distance. When the opening and closing cam 52
moves upward, the rollers 48 and 50 are gradually moved away from
each other. Consequently, the opening and closing arms 42 and 44
open.
[0029] Retaining plates 58 and 60 are secured to the respective
ends of the upper portions 42a and 44a of the opening and closing
arms 42 and 44. As shown in FIGS. 2a to 2e, the retaining plates 58
and 60 have a U-shaped configuration. That is, the upper ends of
the retaining plates 58 and 60 are open. In the state illustrated
in FIG. 1, the retaining plates 58 and 60 face each other across
the bag 1 at respective positions close to each other.
Consequently, a pair of mutually opposing vertical portions 58b and
60b of the retaining plates 58 and 60 and another pair of mutually
opposing vertical portions 58c and 60c thereof face each other
across the lower portions of the bag side edges lb and lc,
respectively. The abutting member 34 of the bag bottom deforming
device 28 extends through a space defined between the bottom 1d of
the bag 1, the horizontal portions 58a (60a) of the retaining
plates 58 and 60, the vertical portions 58b and 58c of the
retaining plate 58, and the vertical portions 60b and 60c of the
retaining plate 60. When the opening and closing cam 52 moves
upward to open the opening and closing arms 42 and 44, the
retaining plates 58 and 60 move away from each other.
[0030] Next, the operation of the bag opening apparatus 10 arranged
as stated above will be described. In a standby state, the suction
cups 12a and 12b of the bag mouth opening device 12 are separate
from each other, and the air nozzle 22 of the inflating device 16
is at a raised position. The abutting member 34 of the bag bottom
deforming device 28 is at a lowered position. The opening and
closing cam 52 of the bag movement restraining device 40 is at a
raised position. Accordingly, the retaining plates 58 and 60 are
away from each other.
[0031] The bag 1 gripped with the grippers 2a and 2b as stated
above is sent to the bag opening apparatus 10 standing by in the
above-described state. When the bag 1 stops at the bag opening
apparatus 10, the opening and closing cam 52 moves downward to
allow the retaining plates 58 and 60 to face each other across the
bag 1 at respective positions close to each other, as shown in FIG.
1. Thus, the vertical portions 58b and 60b of the retaining plates
58 and 60 and the vertical portions 58c and 60c thereof face each
other across the lower portions of the bag side edges 1b and
1c,respectively. At almost the same time or with a predetermined
time delay, the suction cups 12a and 12b approach the bag 1 from
both sides thereof and stick to both sides of the planar portion le
of the bag 1 by vacuum (see FIGS. 2a,3a and 4a). Then, the suction
cups 12a and 12b move away from each other, thereby opening the
mouth portion la of the bag 1. At this time, the grippers 2a and 2b
move toward each other to allow the suction cups 12a and 12b to
move smoothly without hindrance (see FIGS. 2b, 3b and 4b). It
should be noted that the vertical portions 58b, 60b, 58c and 60c
need not come in close contact with the side edges lb and lc of the
bag 1. The vertical portions 58b, 60b, 58c and 60c only need to be
capable of preventing the lower portion of the bag 1 from moving in
a direction perpendicular to the planar portion 1e of the bag 1 to
such an extent that there will be no interference with the
operation of deforming the bag bottom 1d by the abutting member 34
(described later). Therefore, a gap may be present between the bag
1 and the vertical portions 58b, 60b, 58c and 60c as long as it is
possible to prevent movement of the lower portion of the bag 1 in a
direction perpendicular to the planar portion 1e.
[0032] In parallel to the progress of the operation of opening the
bag mouth portion 1a, the nozzle 22 of the inflating device 16
moves downward to enter the bag mouth portion 1a and begins to blow
air into the bag 1 (see FIGS. 2c, 3c and 4c). The suction cups 12a
and 12b continue to move away from each other. However, the
grippers 2a and 2b stop their approaching operation at a
predetermined position. Consequently, the suction cups 12a and 12b
become unable to pull the mouth portion 1a of the bag 1 further and
hence separate from the bag 1. Meantime, the nozzle 22 continues to
move downward and to blow air into the bag 1. Thus, the bag 1 is
fully opened as far as the bottom 1d (see FIGS. 2d, 3d and 4d).
[0033] Then, the abutting member 34 of the bag bottom deforming
device 28 moves upward to push up the bottom 1d of the bag 1 over a
certain area of the central portion in the width direction of the
bag 1, thereby deforming the bottom 1d. At this time, the nozzle 22
stops blowing air into the bag 1. Thus, the central portion of the
bottom 1d is formed into an approximately planar shape extending in
a direction approximately perpendicular to the planar portion 1e of
the bag 1. In other words, the planar portion 1e of the bag 1 rises
from each side edge of the planar bottom portion if at
approximately right angles thereto (see FIGS. 2e and 3e). It should
be noted that when the operation of deforming the bag bottom id is
carried out, the vertical portions 58b and 60b of the retaining
plates 58 and 60 and the vertical portions 58c and 60c thereof face
each other across the bag side edges 1b and 1c,respectively, to
prevent the bag 1 from moving or falling, as has been stated above.
Accordingly, the bag bottom deforming operation is carried out
extremely smoothly.
[0034] After stopping blowing air, the nozzle 22 begins to move
upward and returns to the previous position. Then, the abutting
member 34 moves downward to return to the previous position.
Meanwhile, the opening and closing cam 52 moves upward to separate
the retaining plates 58 and 60 from each other. It should be noted
that the suction cups 12a and 12b separated from the bag 1 ahead of
the bag bottom deforming operation have already returned to the
previous positions, respectively, and the vacuum action derived
from the vacuum source has also already stopped.
[0035] Thus, the bag opening operation is completed. Then, the bag
1 moves to the subsequent step, i.e. filling step. As has been
stated above, the bag 1 has the bottom 1d deformed into a planar
shape over a certain area at the central portion in the width
direction, and the planar portion 1e of the bag 1 rises from each
side edge of the planar bottom portion 1f at approximately right
angles thereto. This structure provides sufficiently strong shape
retaining force to prevent the bag 1 from being undesirably closed
by the action of air resistance during the movement of the bag 1.
In addition, because the bag 1 is deformed into the above-described
shape, the bag's own restoring force as described in connection
with the prior art is kept from acting.
[0036] Although in the foregoing embodiment the bag movement
restraining device 40 is provided separately from the bag bottom
deforming device 28, it should be noted that a bag movement
restraining device may be provided in the bag bottom deforming
device 28. That is, in another embodiment of the present invention,
the upper portion of the outer periphery of the abutting member 34
is formed with a groove extending in a direction perpendicular to
the longitudinal direction of the abutting member 34 so that when
the abutting member 34 is moved upward, the edge portion of the
bottom 1d of the bag 1 enters the groove first, thereby restraining
the movement of the bag bottom 1d.By further moving the abutting
member 34 upward, the bag bottom 1d is deformed as stated
above.
[0037] As has been stated above, according to the present
invention, after the mouth portion of a bag has been opened, the
bottom of the bag is deformed inward of the bag, thereby forming a
portion of the bag bottom into a planar shape similar to the flat
bottom of a self-supporting bag. Thus, the shape of the bag is
changed so that each surface portion of the bag extends from an
edge of the planar bottom portion at approximately right angles
thereto. Therefore, the opened bag is firmly maintained in this
state. Accordingly, there is no likelihood that the opened bag may
be closed by the bag's own restoring force or air resistance
applied to the bag during movement to the subsequent step.
Moreover, the present invention does not use a member that
reciprocates between the bag opening step and the subsequent step
as has been stated in connection with the prior art. Therefore, it
is unnecessary to take into consideration the reset operation time
of such a member. Accordingly, it is possible to increase the
operating speed of packaging machines.
[0038] Further, both the bag bottom deforming device and the bag
movement restraining device can be simplified in arrangement.
Therefore, the production cost is favorably low, and maintenance
and other operations can be performed easily.
[0039] It should be noted that the present invention is not limited
to the foregoing embodiments but can be modified in a variety of
ways.
* * * * *