U.S. patent application number 11/485376 was filed with the patent office on 2007-01-25 for plastic bag opening apparatus.
Invention is credited to Hajime Chikatani.
Application Number | 20070017187 11/485376 |
Document ID | / |
Family ID | 37026590 |
Filed Date | 2007-01-25 |
United States Patent
Application |
20070017187 |
Kind Code |
A1 |
Chikatani; Hajime |
January 25, 2007 |
Plastic bag opening apparatus
Abstract
A plastic bag opening apparatus is provided by which plastic
bags stacked with pins being inserted into pin holes are smoothly
opened and delivered one by one from the uppermost one of the
plastic bags. The apparatus comprises a center holding member (13)
pressing elongations (2) of bags (1) between two pin holes (3) and
side holding members (14) pressing the elongations (2) on both
outer sides of the pin holes (3). Pressing of the elongations (2)
by the holding members (13), (14) is released by rotation of a
rotating member (17), (37) around a rotating shaft (18), (38). When
the elongations (2) are to be pressed, the rotating member (17),
(37) is vertically positioned so that a pushing-up force acting on
the elongations (2) is received by the rotating member (17), (37)
in a dead point state in the vertical direction. A control device
controls such that when the bag 1 is to be opened by being blown
with air, the pressing by the side holding members (14) is released
and when the bag 1 so opened is to be discharged, the side holding
members (14) press the remainder of the stacked plastic bags 1 and
the pressing by the center holding member (13) is released.
Inventors: |
Chikatani; Hajime;
(Tsurugashima-shi, JP) |
Correspondence
Address: |
WENDEROTH, LIND & PONACK, L.L.P.
2033 K STREET N. W.
SUITE 800
WASHINGTON
DC
20006-1021
US
|
Family ID: |
37026590 |
Appl. No.: |
11/485376 |
Filed: |
July 13, 2006 |
Current U.S.
Class: |
53/459 ;
53/385.1; 53/469; 53/573 |
Current CPC
Class: |
B65B 43/36 20130101 |
Class at
Publication: |
053/459 ;
053/573; 053/469; 053/385.1 |
International
Class: |
B65B 41/00 20060101
B65B041/00; B65B 43/26 20060101 B65B043/26; B65B 3/04 20060101
B65B003/04; B65B 43/14 20060101 B65B043/14 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 21, 2005 |
JP |
2005-211191 |
Claims
1. A plastic bag opening apparatus constructed to open plastic
bags, where each of said plastic bags has one edge of its opening
portion elongated to form an elongation, said elongation is
provided with two pin holes and said plastic bags are held together
in a stack with pins, having their upper ends free, being inserted
into said pin holes and opened one by one from the uppermost one of
said plastic bags in the stack by being blown with air obliquely
from above, wherein said plastic bag opening apparatus comprises a
center holding member to press said elongations between said two
pin holes, side holding members to press said elongations on both
outer sides of said pin holes and a control device to control
movements of said center holding member and side holding members
such that when said plastic bags are to be opened by the air
blowing, the pressing by said side holding members is released and
when said plastic bags so opened are to be discharged, said side
holding members press the remainder of said plastic bags in the
stack and the pressing by said center holding member is released
and each of said center holding member and side holding members is
constructed such that the pressing of said elongations and release
thereof are carried out by rotation of a rotating lever around a
rotating shaft and when said elongations are to be pressed, said
rotating lever is vertically positioned so that a pushing-up force
acting on said elongations is received by said rotating lever in a
dead point state in the vertical direction.
2. A plastic bag opening apparatus as claimed in claim 1, wherein
said rotating shaft to rotate said rotating lever for moving said
center holding member and side holding member is constructed to be
rotated by elongation and contraction of an air cylinder.
3. A plastic bag opening apparatus as claimed in claim 2, wherein
the pressing by said center holding member and side holding member
and release thereof are carried out by a construction such that
said rotating lever has its one end fitted with an engaging roller
and a member having a slot with which said engaging roller engages
is moved by rotation of said rotating lever around said rotating
shaft.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention generally relates to a plastic bag
opening apparatus and more particularly to an apparatus for opening
plastic bags in a stack, one by one, where each of the bags has one
edge of its opening portion elongated, the edge so elongated is
provided with two pin holes and a multiplicity of the bags are held
together with pins, having upper ends free, being inserted into the
pin holes.
[0003] 2. Description of the Prior Art
[0004] In a packaging apparatus for making packages by filling
articles in plastic bags for packaging purpose, it is necessary to
open the bags, one by one, out of a multiplicity of the bags held
together in a stack. In order to facilitate operation to open the
bags, one by one, out of the stacked bags for packaging purpose,
conventionally, it is so carried out that, as shown in FIG. 8, a
plastic bag 1 is formed having one edge of its opening portion 0
elongated to form an elongation 2, the elongation 2 is provided
with two pin holes 3, as shown in FIG. 9, and pins 04 are inserted
into the pin holes 3 so that a multiplicity of the bags 1 are held
together in a stack and the bags 1 in this state are opened, one by
one, to be filled with articles.
[0005] When the bags held with the pins 04 being inserted into the
pin holes 3, as shown in FIG. 9, are opened, one by one, to be used
for packaging, each of the plastic bags 1 so opened must be
released from the pins 04. Conventionally, it is so carried out
that while the pins 04 are held inserted in the pin holes 3,
articles are filled in the plastic bag 1 and by action of force
acting following the packaging work or the like, the plastic bag 1
is torn off at the portion of the pin holes 3 for release from the
pins 04. Numeral 05 designates a perforated line provided so that
the plastic bag 1 can be easily torn off at the portion of the pin
holes 3.
[0006] Nevertheless, at the portion of the pin holes 3 of the
plastic bag 1 so torn off, there remain broken fractions and the
exterior appearance of packaged articles is damaged. Hence, in
order to improve this problem, the applicant here has heretofore
proposed plastic bag opening methods by the Japanese laid-open
patent applications 2000-255514 and 2003-11920. In these methods,
as shown in FIG. 10, pins 4 having upper ends free are inserted
into pin holes of a plastic bag 1 to hold together the plastic bags
1 in a stack, air is blown obliquely from above to partially open
the plastic bag 1 and then an opening member is inserted into the
bag to enlarge the opening of the bag. At the time of so enlarging
the opening, the plastic bag 1 is drawn out of the pins 4 without
being torn or broken.
[0007] In these new methods, it is necessary to always hold in a
stable state an upper surface of the plastic bags 1 stacked with
the pins 04 being inserted into the pin holes 3. Especially, when
the uppermost bag fully opened is to be drawn out of the pins 04,
the stack of the remaining plastic bags 1 is often deformed to
thereby irregularly move the bags 1 so that the bag opening
operation is obstructed. In order to avoid the obstruction, it is
necessary to accurately hold the stack of the bags so that the bags
1 can be smoothly drawn out of the pins 04. For this purpose, there
is provided a holding member 5 so that the upper surface of the
stacked bags 1 pushed up from below is always held at a
predetermined level. That is, even if the stacked bags 1 are
consumed one by one and the height of the stack is changed, the
remaining bags 1 are pushed up from below and the upper surface of
the bags 1 is pressed to be accurately held at the predetermined
level by the holding member 5. What is now needed is an apparatus
to securely operate the holding member 5 so that the upper surface
of the stacked bags 1 pushed up from below is pressed to be held at
the predetermined level as well as the pressing is released so that
the bags 1 are discharged one by one from the uppermost one.
SUMMARY OF THE INVENTION
[0008] In order to satisfy the above-mentioned necessity, it is an
object of the present invention to provide a bag opening apparatus
constructed to open plastic bags in a stack, one by one from the
uppermost one, by blowing air obliquely from above toward the bags,
where each of the bags has one edge of opening portion elongated to
form an elongation, the elongation is provided with two pin holes
and the bags are held together with pins, having upper ends free,
being inserted into the pin holes. In the plastic bag opening
apparatus so constructed, in order for the plastic bags to be
smoothly opened and stably delivered, a pushing-up force acting on
the plastic bags from below is received to thereby always hold an
upper surface of the stacked plastic bags at a predetermined level
as well as pressing of the stacked plastic bags and release thereof
can be quickly and accurately carried out to thereby securely open
and deliver the plastic bags one by one.
[0009] That is, as a plastic bag opening apparatus that can achieve
the above-mentioned object, the present invention provides a
plastic bag opening apparatus constructed to open plastic bags,
where each of the plastic bags has one edge of its opening portion
elongated to form an elongation, the elongation is provided with
two pin holes and the plastic bags are held together in a stack
with pins, having their upper ends free, being inserted into the
pin holes and opened one by one from the uppermost one of the
plastic bags in the stack by being blown with air obliquely from
above, characterized in that the plastic bag opening apparatus
comprises a center holding member to press the elongations between
the two pin holes, side holding members to press the elongations on
both outer sides of the pin holes and a control device to control
movements of the center holding member and side holding members
such that when the plastic bags are to be opened by the air
blowing, the pressing by the side holding members is released and
when the plastic bags so opened are to be discharged, the side
holding members press the remainder of the plastic bags in the
stack and the pressing by the center holding member is released and
each of the center holding member and side holding members is
constructed such that the pressing of the elongations and release
thereof are carried out by rotation of a rotating lever around a
rotating shaft and when the elongations are to be pressed, the
rotating lever is vertically positioned so that a pushing-up force
acting on the elongations is received by the rotating lever in a
dead point state in the vertical direction.
[0010] In the plastic bag opening apparatus according to the
present invention, the elongation is formed by an edge of a lower
sheet out of two sheets forming the bag opening portion being
elongated and while the elongations of the bags are held pressed by
the center holding member between the two pin holes, air is blown
obliquely from above toward the bag opening portion. Thereby, the
uppermost one of the bags held together in the stack is partially
opened and, at this time, the bag at the portion of the pin holes
is drawn out of the pins having their upper ends free.
[0011] Then, an opening member that is vertically and/or
horizontally enlargeable is inserted into the bag opening portion
so partially opened and the bag opening portion is enlarged to be
fully opened. Thereby, the elongation, except the portion pressed
by the center holding member between the two pin holes, is lifted
up so that the bag at the portion of the pin holes still inserted
with the pins can be fully drawn out of the pins.
[0012] In this way, the bag opening portion is enlarged and the
plastic bag at the portion of the pin holes is drawn out of the
pins without being torn off or broken so that the plastic bag
becomes ready for being filled with articles. In the bag so opened,
there remains no broken fraction in the vicinity of the pin holes
differently from the conventional case and packaged articles having
an excellent exterior appearance can be produced. The remainder of
the stacked plastic bags after the uppermost bag is so opened are
pressed at the portion of the elongations by the side holding
members on both outer sides of the pin holes. Hence, even if the
pressing by the center holding member is released for discharge of
the opened bag, the stacked plastic bags are pressed by the side
holding members and the stacked state of the bags can be stably
held.
[0013] Also, in the plastic bag opening apparatus according to the
present invention, the center holding member and side holding
member are respectively constructed such that the pushing-up force
acting on the elongations from below is received by the rotating
lever vertically positioned so as to be in the dead point state in
the vertical direction. That is, the pushing-up force to push up
the stacked plastic bags from below is securely received by the
center holding member and side holding members and the upper
surface of the stacked plastic bags can be always held at the
predetermined level. When the pressing of the stacked plastic bags
is to be released, the rotating lever is only rotated around the
rotating shaft and thereby the bag opening operation can be
smoothly carried out. Also, when the stacked plastic bags are to be
pressed, it is carried out by a simple structure that the rotating
lever vertically positioned becomes the dead point state in the
vertical direction to thereby securely receive the pushing-up force
acting from below. Thus, even if the height of the stacked plastic
bags changes or the pushing-up force from below changes, the
stacked plastic bags are securely held and the upper surface of the
plastic bags can be always held at the predetermined level.
[0014] In this way, by the construction that at least one of the
center holding member and side holding member always abuts on the
upper surface of the stacked plastic bags, the stacked plastic bags
pushed up from below are securely held so that the upper surface
thereof is maintained at the predetermined level. Thus, according
to the plastic bag opening apparatus of the present invention, the
plastic bags in the stack can be stably opened one by one from the
uppermost one of the plastic bags.
[0015] In the plastic bag opening apparatus of the present
invention as mentioned above, if the rotating shaft to rotate the
rotating lever for moving the center holding member and side
holding member is constructed to be rotated by elongation and
contraction of an air cylinder, there is obtained a plastic bag
opening apparatus in which a change-over between a state where the
rotating lever vertically positioned to be in the dead point state
receives the pushing-up force acting from below and a state where
the rotating lever rotated around the rotating shaft releases the
pressing of the elongations of the bag opening portion can be
easily, quickly and securely carried out.
[0016] Also, in the plastic bag opening apparatus of the present
invention as mentioned above, if the pressing by the center holding
member and side holding member and release thereof are carried out
by a construction such that the rotating lever has its one end
fitted with an engaging roller and a member having a slot with
which the engaging roller engages is moved by rotation of the
rotating lever around the rotating shaft, there is obtained a
plastic bag opening apparatus in which the center holding member
and side holding members are easily moved by rotation of the
rotating lever so that the bag opening operation can be smoothly
carried out.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 is a plan view showing plastic bags set in a stack to
be opened in a plastic bag opening apparatus according to the
present invention.
[0018] FIG. 2 is an explanatory view showing a state that a bag
opening operation of the plastic bags shown in FIG. 1 is being
carried out by the plastic bag opening apparatus according to the
present invention.
[0019] FIG. 3 is a view seen in the direction of arrow A of FIG.
2.
[0020] FIG. 4 is a side view showing a structure of a center
holding member used in the plastic bag opening apparatus according
to the present invention, wherein the stacked plastic bags are
pressed by the center holding member.
[0021] FIG. 5 is the same side view of the center holding member of
FIG. 4, wherein the pressing of the stacked plastic bags by the
center holding member is released.
[0022] FIG. 6 is a side view showing a structure of a side holding
member used in the plastic bag opening apparatus according to the
present invention, wherein the stacked plastic bags are pressed by
the side holding member.
[0023] FIG. 7 is the same side view of the side holding member of
FIG. 6, wherein the pressing of the stacked plastic bags by the
side holding member is released.
[0024] FIG. 8 is a cross sectional side view of the plastic bag
shown in FIG. 1.
[0025] FIG. 9 is an explanatory perspective view showing a state
that stacked plastic bags are held together by pins in a plastic
bag opening apparatus in the prior art.
[0026] FIG. 10 is an explanatory side view showing a state that
stacked plastic bags held together by pins having upper ends free
are being opened in a plastic bag opening apparatus in the prior
art.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0027] Herebelow, the present invention will be concretely
described based on an embodiment of a plastic bag opening apparatus
according to the present invention with reference to FIGS. 1 to 3.
In FIGS. 1 to 3, numeral 1 designates a plastic bag for packaging
purpose that has its three sides except an opening portion 0
closed. One edge of a plastic sheet out of two plastic sheets
forming the opening portion 0, that is, a lower side sheet in the
figures, is elongated to form an elongation 2 and the elongation 2
is provided with two pin holes 3 arranged with an interval
maintained between them.
[0028] A multiplicity of the plastic bags 1 so formed are held
together in a stack with two pins 4, having their upper ends free,
being inserted into the pin holes 3. The stacked plastic bags 1 are
pressed by a center holding member 13 at the portion of the
elongations 2 between the two pin holes 3. Also, the elongations 2
of the stacked plastic bags 1 are pressed by side holding members
14 at peripheral portions of the elongations 2 on both outer sides
of the two pin holes 3.
[0029] The stacked plastic bags 1 are pushed up from below with a
predetermined pressure by an air cylinder or the like and the
construction is so made that this pushing-up force is received by
the center holding member 13 and side holding members 14 to thereby
always hold an upper surface of the stacked plastic bags 1 at the
same level. In order for the stacked plastic bags 1 to be pushed up
from below with the predetermined pressure by an air cylinder or
the like so that the same horizontal state is always maintained
regardless of the height of the stacked bags, an appropriate device
of known constructions may be employed and one example thereof is
shown in the Japanese laid-open patent application 2002-20510.
[0030] After the plastic bags are held together in the stack, as
mentioned above, pressing by the side holding members 14 is
released and air 7 is blown obliquely from above toward the opening
portion 0 of the plastic bags from an air nozzle 6 so that the
opening portion 0 of the uppermost bag is opened, as shown by solid
lines 8 in FIG. 2.
[0031] The air 7 blown from the air nozzle 6 is a hot air of
temperature of 50 to 80.degree. C. so that temperature of the bag 1
that is being opened is increased and flexibility thereof is
enhanced. Thereby, when articles are to be filled in the bag 1, the
bag is prevented from being broken by corner portions or the like
of the articles, which is preferable, although not essential. The
concrete temperature of the air 7 can be appropriately selected in
consideration of a material and thickness of the bag to be used,
shape and stiffness of the articles to be filled, etc.
[0032] Then, an opening member 9 is inserted into the opening so
formed by the air 7 from the air nozzle 6. The opening member 9
comprises four bars, that is, two lower bars 10 and two upper bars
11. Intervals between the lower bars 10 and upper bars 11, between
the two lower bars 10 and between the two upper bars 11 are
changeable by vertical and horizontal movements of the bars.
[0033] After the opening member 9 is inserted into the opening of
the bag 1, the upper bars 1 1 are moved upward so that the opening
of the bag 1 is enlarged, as shown by two dotted chain lines 12. As
the result of the bag partial opening action by the air 7 and/or
the opening enlarging action by the opening member 9, the bag 1 at
the portion of the pin holes 3 is drawn out of the pins 4, having
their upper ends free, that have been inserted into the pin holes
3. At this time, the elongation 2 is by no means broken or torn at
the portion of the pin holes 3.
[0034] In this way, even if the pressing by the side holding
members 14 is released, the pushing-up force of the stacked plastic
bags 1 acting from below is received by the center holding member
13 so that the upper surface of the plastic bags 1 can be always
maintained at the same level.
[0035] After the uppermost bag 1 is drawn out of the pins 4 at the
portion of the pin holes 3, the remaining stacked plastic bags 1
are held together by the side holding members 14, as shown in FIG.
3.
[0036] Next, construction of the center holding member 13 and side
holding members 14 will be described with reference to FIGS. 4 to
7.
[0037] As shown in FIGS. 4 and 5, the center holding member 13 is
pivotably fitted around a pivotal shaft 15 and is provided with a
slot 16. Numeral 17 designates a rotating member, constituting a
rotating lever of the present invention, that is rotatably fitted
around a rotating shaft 18. An engaging roller 19 is rotatably
fitted to the rotating member 17 and is fitted in the slot 16 of
the center holding member 13 to be rollably moved along the slot
16.
[0038] The rotating shaft 18 to which the rotating member 17 is
rotatably fitted is provided with a lever 20 and the lever 20 is
pivotably fitted to an upper end of a piston rod 22 of an air
cylinder 21.
[0039] By this construction, when a piston of the air cylinder 21
is elongated, the rotating shaft 18 is rotated via the lever 20,
the rotating member 17 is rotated around an axis of the rotating
shaft 18, the engaging roller 19 is moved along the slot 16 and the
center holding member 13 is pivotally rotated around the pivotal
shaft 15 in the clockwise direction in FIGS. 4 and 5. That is, a
press state shown in FIG. 4 where the center holding member 13
presses the plastic bags 1 stacked with the pins 4 being inserted
in the pin holes 3 is changed to a release state shown in FIG. 5
where the pressing by the center holding member 13 is released by
the center holding member 13 being so clockwise rotated.
[0040] On the other hand, while the center holding member 13 is in
the state pressing the stacked plastic bags 1, as shown in FIG. 4,
a line connecting axes of the engaging roller 19 and rotating shaft
18 of the rotating member 17 is maintained vertical. Hence, even if
a downward pressing force acts on the engaging roller 19 from the
center holding member 13, this force only acts on the rotating
shaft 18 right below thereof via the vertical rotating member 17
and by no means becomes a force to rotate the rotating member 17.
That is, the rotating member 17 is in a dead point state. It is to
be noted that in FIGS. 4 and 5, numeral 23 designates an air
cylinder that always pushes up the stacked plastic bags 1. The
pushing-up force of the air cylinder 23 is received by the center
holding member 13 so that the upper surface of the stacked plastic
bags 1 can be held at the same level.
[0041] Next, construction of the side holding member 14 will be
described with reference to FIGS. 6 and 7. In FIGS. 6 and 7, the
side holding member 14 is fitted with a lever 31 that downwardly
elongates and the lever 31 is fitted with a sliding member 32 via a
bolt 33. The sliding member 32 is supported being fitted movably up
and down in a groove 34 of a strut 30.
[0042] The lever 31 has its lower end fitted with a receiving
member 35 and the receiving member 35 is provided with a slot 36
that horizontally elongates. Numeral 37 designates a rotating
member constituting a rotating lever of the present invention. The
rotating member 37 has its upper end side fitted with a rotating
shaft 38 that is connected to an air cylinder and its lever end
side fitted rotatably with an engaging roller 39.
[0043] The engaging roller 39 fitted to the lower end of the
rotating member 37 is fitted in the slot 36 of the receiving member
35 and the construction is so made that when the rotating member 37
is rotated around an axis of the rotating shaft 38, the receiving
member 35 is moved up and down via the engaging roller 39.
[0044] In a state shown in FIG. 6 where the side holding member 14
is in the state pressing the stacked plastic bags 1, a line
connecting axes of the engaging roller 39 and rotating shaft 38 of
the rotating member 37 is maintained vertical. Hence, even if an
upward pressing force acts on the engaging roller 39 from the side
holding member 14 via the receiving member 35, this force only acts
on the rotating shaft 38 right above thereof via the vertical
rotating member 37 and by no means becomes a force to rotate the
rotating member 37 that is in a dead point state. It is to be noted
that in FIGS. 6 and 7, numeral 40 designates an air cylinder that
always pushes up the stacked plastic bags 1. The pushing-up force
of the air cylinder 40 is received by the center holding member 13
and side holding member 14 so that the upper surface of the stacked
plastic bags 1 can be held at the same level.
[0045] In FIG. 6, when the rotating member 37 is rotated in the
clockwise direction around the axis of the rotating shaft 38, the
receiving member 35 is upwardly moved and the side holding member
14 is also upwardly moved so that the pressing force acting on the
stacked plastic bags 1 from the side holding member 14 is released,
as shown in FIG. 7.
[0046] It is to be noted that as in the case of the rotating member
17 with respect to the center holding member 13, the rotating
member 37 is rotated around the axis of the rotating shaft 38 by
the rotating shaft 38 being rotated by an appropriate air cylinder
(not shown).
[0047] Now returning to FIG. 3, when the bag 1 is opened to the
maximum size by the interval between the lower bars 10 and upper
bars 11 being enlarged, as mentioned above, articles to be packaged
are inserted into the bag 1 to be filled therein. It is to be noted
that at an appropriate time before filling the articles in the bag
1, during the filling time thereof or after the filling thereof,
the bag pressing force by the center holding member 13 may be
weakened so that the uppermost bag 1 so opened is released from the
stacked state of the bags.
[0048] When the bag 1 filled with the articles is to be discharged,
the edge portion of the bag 1 is released from the center holding
member 13. Even if the bag pressing force by the center holding
member 13 is released, the elongations 2 of the bags 1 stacked
thereunder are pressed by the side holding members 14 on both outer
sides of the pins 4 so that the stacked state of the bags 1 can be
maintained in order. Also, the pushing-up force from below of the
plastic bags 1 in the stacked state is received by the side holding
members 14 in the dead point state, as mentioned above, so that the
upper surface of the plastic bags 1 can be maintained at the
predetermined level.
[0049] As for the opening member 9, the construction is made such
that when the opening member 9 is inserted into the opening of the
bag 1, it can enlarge the opening in the vertical direction, in the
horizontal direction or both in the vertical and horizontal
directions and the size thereof may be appropriately selected
corresponding to the size, shape or the like of the bag to be
opened.
[0050] In the foregoing, while the present invention has been
concretely described based on the embodiment, as illustrated, the
present invention is not limited to the embodiment but, as a matter
of course, may be added with various modifications in the concrete
structure and construction without departing from the scope of the
claims of the present invention as appended herein.
[0051] For example, in the embodiment, while the construction of
the opening member 9 has been described to enlarge the opening of
the bag 1 by the upper bars 11 being moved straightly upwardly, as
shown in FIG. 3, in place thereof, such a construction may be
employed that four bars are moved obliquely upwardly and obliquely
downwardly with an oblique angle of 45.degree., respectively, so as
to enlarge the opening of the bag 1. That is, an appropriate one of
known constructions as the opening member of this kind can be
employed.
[0052] Also, in the embodiment, the construction of the rotating
members 17, 37 as the rotating lever has been described such that
the engaging rollers 19, 39, fitted to the rotating members 17, 37,
are fitted in the slots 16, 36 so that when the rotating members
17, 37 are rotated, the center holding member 13 and side holding
members 14 are caused to press the stacked bags 1 or to release the
pressing and when the line connecting the rotating shafts 18, 38
and engaging rollers 19, 39 becomes vertical, the dead point state
of the rotating members 17, 37 is formed. But, not being limited
thereto, an appropriate construction, except the illustrated one,
of the center holding member and side holding member may be
employed, if they are constructed such that when the rotating
member is rotated around the rotating axis, the pressing of the
elongations 2 of the bags 1 is released and when the elongations 2
of the bags 1 are to be pressed, the rotating member becomes
vertical to form the dead point state so that the pushing-up force
from below of the elongations 2 is received by the rotating
member.
* * * * *