U.S. patent application number 09/911621 was filed with the patent office on 2002-02-07 for vertical bag form-fill-seal packaging machine.
Invention is credited to Fukuda, Masao, Iwasa, Seisaku, Shimomae, Yoshinobu.
Application Number | 20020014055 09/911621 |
Document ID | / |
Family ID | 18725268 |
Filed Date | 2002-02-07 |
United States Patent
Application |
20020014055 |
Kind Code |
A1 |
Iwasa, Seisaku ; et
al. |
February 7, 2002 |
Vertical bag form-fill-seal packaging machine
Abstract
The present invention provides a first transfer unit instead of
a stationary chute. The first drive unit drives the first transfer
unit and is controlled to maintain a bag ejection interval or bag
posture. Thus, variation of the bag-to-bag pitch and bag posture
even in a high-speed operation with an improved bag-forming
capacity is prevented.
Inventors: |
Iwasa, Seisaku; (Kurita-gun,
JP) ; Fukuda, Masao; (Kurita-gun, JP) ;
Shimomae, Yoshinobu; (Kurita-gun, JP) |
Correspondence
Address: |
SHINJYU GLOBAL IP COUNSELORS, LLP
1233 20TH STREET, NW, SUITE 700
WASHINGTON
DC
20036-2680
US
|
Family ID: |
18725268 |
Appl. No.: |
09/911621 |
Filed: |
July 25, 2001 |
Current U.S.
Class: |
53/551 |
Current CPC
Class: |
B65B 57/08 20130101;
B65B 51/306 20130101; B65B 61/28 20130101; B65B 61/00 20130101;
B65B 9/207 20130101; B65B 9/2028 20130101 |
Class at
Publication: |
53/551 |
International
Class: |
B65B 009/20 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 1, 2000 |
JP |
2000-232617 |
Claims
What is claimed is:
1. A vertical bag form-fill-seal packaging machine for forming bags
by sealing a continuous tubular packaging material in which a
product to be packaged is filled, and for separating and ejecting
each of the bags, the machine comprising: a first transfer unit for
transferring the separated bags to another transfer unit or
transfer machine provided in a downstream process, a first drive
unit for driving the first transfer unit, and a control unit for
controlling the first control unit, said control unit controlling
the bag ejection interval or the posture of the bags to be ejected
after being transferred by the first transfer unit.
2. The machine as defined in claim 1, wherein the control unit
provides control so that the bag ejection interval is larger than
the bag separation interval.
3. The machine as defined in claim 1, wherein the first transfer
unit is a belt.
4. The machine as defined in claim 2, wherein the first transfer
unit is a belt.
5. The machine as defined in claim 3, wherein the belt is inclined
so that the bags move diagonally downward.
6. The machine as defined in claim 4, wherein the belt is inclined
so that the bags move diagonally downward.
7. The machine as defined in claim 3, wherein the first transfer
unit comprises two belts holding each of the bags in a sandwiched
manner.
8. The machine as defined in claim 7, wherein the first transfer
unit is such that a part of a transfer passage formed between the
two belts is inclined so that the direction of the bag transfer
changes as the bag moves therethrough.
9. The machine as defined in claim 7, further comprising a means
for changing the distance between the two belts, wherein the
control unit controls the means for changing the distance between
the two belts according to the bags, so as to adjust the distance
between the two belts.
10. The machine as defined in claim 8, further comprising a means
for changing the distance between the two belts, wherein the
control unit controls the means for changing the distance between
the two belts according to the bags, so as to adjust the distance
between the two belts.
11. The machine as defined in claim 7, wherein the sealing is
heat-sealing and the machine further comprises a cooling unit for
spraying a cooling gas on the sealed part of each of the bags held
in a sandwiched manner by the two belts.
12. The machine as defined in claim 1, further comprising: a second
transfer unit for receiving, transferring, and ejecting the bags
transferred from the first transfer unit, and a second drive unit
for driving the second transfer unit, wherein the control unit
further controls the second drive unit.
13. The machine as defined in claim 12, wherein the transfer unit
is a belt with a guide bar approximately orthogonal to the
direction of transfer.
14. The machine as defined in claim 1, further comprising a memory
storage unit for storing control settings for each set of products
to be packaged, wherein the control unit performs control according
to the settings stored in the memory storage unit.
15. The machine as defined in claim 14, wherein at least one of the
control setting items to be stored in the memory storage unit is
the speed of the drive unit.
16. The machine as defined in claim 15, wherein the control unit
provides data at least on the bag ejection time interval to the
external equipment in the downstream process.
17. The machine as defined in claim 7, further comprising a memory
storage unit for storing control settings for each set of products
to be packaged, wherein the control unit performs control according
to the settings stored in the memory storage unit.
18. The machine as defined in claim 17, wherein at least one of the
control setting items to be stored in the memory storage unit is
the speed of the drive unit.
19. The machine as defined in claim 18, wherein the control unit
provides data at least on the bag ejection time interval to the
external equipment in the downstream process.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a vertical bag
form-fill-seal packaging machine, and more particularly to a
vertical bag form-fill-seal packaging machine for forming bags by
sealing a continuous tubular packaging material in which a product
to be packaged is filled, and then separating and ejecting each of
the bags.
[0003] 2. Background Information
[0004] Vertical bag form-fill-seal packaging machines exist as
packaging devices that fill a product to be packaged, such as food,
into bags which are being formed at the same time. In a
conventional vertical bag form-fill-seal packaging machine, a
packaging material in a sheet-like film form is fed over a former
and into a tube. The material is formed into a tubular shape that
conforms to the vertically long tube through which it goes. The
overlapped vertical ends of the tubular packaging material are then
sealed (heat-sealed) by a vertical sealing mechanism. The product
to be packaged, which is allowed to drop from a higher position, is
filled into the tubular packaging material via the tube. Then, the
portion of the tubular packaging material that will become the top
of a bag and the bottom of its next bag is transversely sealed by a
transverse sealing mechanism provided under the tube. Immediately
after this, a cutter cuts the center of the transversely sealed
portion. In such a vertical bag form-fill-seal packaging machine,
two types of operations, the forming of the bags and the filling of
the product to be packaged into the bags, are carried out
continuously as described above.
[0005] In such a conventional vertical bag form-fill-seal packaging
machine, each of the bags separated from the following bag by the
cutter falls freely onto a stationary chute provided below the
transverse sealing mechanism, and is led to a belt conveyor in a
downstream process. The stationary chute is similar to a playground
slide made of a metal plate or the like, and plays the role of
transferring the bag to the belt conveyor in the downstream process
by taking advantage of gravity.
[0006] In a conventional vertical bag form-fill-seal packaging
machine, the bags are allowed to fall freely using gravity before
they are ejected onto the belt conveyer in the downstream process.
With improvements in bag-forming capacity in recent years, however,
the quantity of the bags ejected per unit of time has increased.
With the traditional quantities of bags to be ejected, a small
degree of variation in the bag ejection interval and posture would
not lead to a problem on the belt conveyor or other devices in the
downstream process. However, with the quantity of the bags to be
ejected ever increasing, a problem with the devices could result in
the downstream process. Particularly, with the increase in the
quantity of the bags to be ejected, or the higher-speed operation
of the vertical bag form-fill-seal packaging machine, which causes
the bags to be ejected at a shorter interval, a minor variation in
the bag ejection intervals may lead to a problem with the devices
in the downstream process. For example, two bags may be loaded
instead of one on a weight checker or a seal checker in the
downstream process, or the mishandling of the bags or the
disorganization of the file or files of the bags may result at a
boxing device. Such problems could stop the production line, thus
lowering the line operation rate and preventing the achievement of
high-speed operation.
[0007] In view of the above, there exists a need for a vertical bag
form-fill-seal packaging machine which overcomes the above
mentioned problems in the prior art. This invention addresses this
need in the prior art as well as other needs, which will become
apparent to those skilled in the art from this disclosure.
SUMMARY OF THE INVENTION
[0008] A principal object of the present invention is to provide a
vertical bag form-fill-seal packaging machine that prevents
variation in the pitch and posture of the bags that are
continuously ejected.
[0009] A vertical bag form-fill-seal packaging machine in
accordance with a first aspect of the present invention provides a
vertical bag form-fill-seal packaging machine for forming bags by
sealing a continuous tubular packaging material in which a product
to be packaged is filled, and then separating and ejecting each of
the bags. The vertical bag form-fill-seal packaging machine
includes a first transfer unit, a first drive unit, and a control
unit. The first transfer unit transfers the separated bags to
another transfer unit or conveyor provided in a downstream process.
The first drive unit drives the first transfer unit. The control
unit controls the first drive unit to control the interval or the
posture of the bags to be ejected after being transferred by the
first transfer unit. In this case, the first transfer unit is
provided instead of a conventional stationary chute. The bag
interval and the posture of the bags to be ejected are maintained
by controlling the first drive unit that drives the first transfer
unit. Therefore, even during high-speed operation with an improved
bag-forming capacity, the variation in the pitch and the posture of
the bags can be reduced. With a conventional stationary chute, on
which frictional resistance (as the bag slides) and an impact (as
the bag comes off the chute) occurs, there is a high probability
that the pitch and the posture of the bags may be adversely
affected. By using the packaging machine as defined in the first
aspect of the present invention, in which the first transfer unit
is provided and the transfer of the bag on the first transfer unit
is controlled, variations in the bag ejection pitch and posture are
prevented.
[0010] A vertical bag form-fill-seal packaging machine in
accordance with a second aspect of the present invention is the
machine as defined in the first aspect, wherein the control unit
provides control so that the bag ejection interval is larger than
the bag separation interval. The bags are prevented from being
transferred to the conveyor or the transfer unit or other devices
in the downstream process without a proper interval.
[0011] A vertical bag form-fill-seal packaging machine in
accordance with a third aspect of the present invention is the
machine as defined in either of the previous aspects, wherein the
first transfer unit is a belt.
[0012] In this aspect, a relatively simple structure having a belt
and a first drive unit for moving the belt, such as a motor, is
used to restrict variation in the bag ejection pitch and posture.
It is easy and inexpensive to incorporate this structure into a
vertical bag form-fill-seal packaging machine of the present
invention or during initial construction to retrofit it to a
conventional vertical bag form-fill-seal packaging machine. To
prevent variation in bag posture that may be caused by the drop
impact, the belt is preferably set in a position so that it
contacts the bags immediately after they are separated from the
supply roll of packaging material.
[0013] A vertical bag form-fill-seal packaging machine in
accordance with a fourth aspect of the present invention is the
machine as defined in the third aspect, wherein the belt is
inclined so that the bags move diagonally downward. In this case,
with the belt inclined, the bags separated from the supply roll of
the packing material surely contact the belt. The incline of the
belt is such that it allows the bags to move diagonally downward,
thereby reducing the impact that may be caused on the bags upon
their contact with the belt, thus reducing changes in bag posture.
Additionally, preventing the bags from being transferred in a
stand-up posture, the bag-to-bag interval is more constant. The
incline of the belt further contributes to a reduction in the
impact that may be caused when the bags move from the belt to the
transfer unit or conveyor in the downstream process.
[0014] A vertical bag form-fill-seal packaging machine in
accordance with a fifth aspect of the present invention is the
machine as defined in the third or fourth aspect, wherein the first
transfer unit includes two belts holding each of the bags in a
sandwiched manner. In this case, the bags are transferred while
being held by the two belts in a sandwiched manner. Thus, the bags
are securely held, thereby reducing problematic variations in the
bag ejection pitch that may be caused by the slippage of the bags
and belt.
[0015] A vertical bag form-fill-seal packaging machine in
accordance with a sixth aspect of the present invention is the
machine as defined in the fifth aspect, wherein the first transfer
unit is such that a part of a transfer passage formed between the
two belts is inclined so that the direction of the bag transfer
changes as the bag moves therethrough.
[0016] A vertical bag form-fill-seal packaging machine in
accordance with a seventh aspect of the present invention is the
machine as defined in the fifth or sixth aspect, further including
a means for changing the distance between the two belts, wherein
the control unit controls the means for changing the distance
between the two belts according to the bags, so as to adjust the
distance between the two belts. In this case, by taking advantage
of the structure that holds each of the bags with the two belts in
a sandwiched manner, the volume of the gas to be filled into the
bags is optimized. In other words, by adjusting the distance
between the two belts, the volume of the gas to be filled into the
formed bags can be controlled, thus making the volume of the bags
to be ejected uniform. Generally with the vertical bag
form-fill-seal packaging machine, the gas to be filled is sprayed
into the bags at the time of bag forming. By spraying it with a
little more than the required amount and making the volume of the
bags uniform through the adjustment of the belt-to-belt distance,
the volume of the bags to be ejected will be substantially uniform
even if the pressure of the gas supply unit has changed.
[0017] A vertical bag form-fill-seal packaging machine in
accordance with an eighth aspect of the present invention is the
machine as defined either in the fifth, sixth, or seventh aspects,
wherein the sealing is heat-sealing and the machine further
includes a cooling unit for spraying a cooling gas on the sealed
part of each of the bags held in a sandwiched manner by the two
belts. In this case, by taking advantage of the structure that
holds each of the bags in a sandwiched manner, a gas for cooling is
sprayed onto the bags thus held in a sandwiched manner, to ensure
the bonding strength of the heat-sealed part. With a conventional
machine, there is a high possibility that the posture of the bags
to be ejected varies if a cooling gas is sprayed. However, with the
two belts sandwiching the bags in the machine of the present
invention, the posture will rarely be affected even when cooled by
spraying a gas. In addition, the cooling strengthens the sealing,
thereby reducing the problem of bag breakage that may cause the
production line to stop while the bags are still being
transferred.
[0018] A vertical bag form-fill-seal packaging machine in
accordance with a ninth aspect of the present invention is the
machine as defined in the first or second aspect, further including
a second transfer unit for receiving, transferring, and ejecting
the bags transferred from the first unit, and a second drive unit
for driving the second transfer unit, wherein the control unit
further controls the second drive unit in addition to the first
drive unit.
[0019] A vertical bag form-fill-seal packaging machine in
accordance with tenth aspect of the present invention is the
machine as defined in the ninth aspect, wherein the transfer unit
is a belt with a guide bar approximately orthogonal to the
direction of transfer. In this case, the transfer unit, which is a
belt, has a guide bar that prevents the bags from shifting on the
bag.
[0020] A vertical bag form-fill-seal packaging machine in
accordance with an eleventh aspect of the present invention is the
machine as defined in any of the previous aspects, further
including a memory storage unit for storing control settings for
each set of products to be packaged, wherein the control unit
maintains control according to the settings stored in the memory
storage unit.
[0021] A vertical bag form-fill-seal packaging machine in
accordance with a twelfth aspect of the present invention is the
machine as defined in the eleventh aspect, wherein at least one of
the control setting items to be stored in the memory storage unit
is the speed of the drive unit. In this case, by setting the drive
unit speed according to the bags, it becomes possible to adjust the
bag-to-bag pitch to be ejected and the bag ejection time interval
to reflect the operating conditions of the equipment in the
downstream process.
[0022] A vertical bag form-fill-seal packaging machine in
accordance with a thirteenth aspect of the present invention is the
machine as defined in the twelfth aspect, wherein the control unit
provides data at least on the bag ejection time interval to the
external equipment in the downstream process. In this case, because
the data on the time interval between each bag's ejection are
provided to the external equipment in the downstream process, an
operation synchronizing with the ejection time intervals of the
bags sent from the vertical bag form-fill-seal packaging machine
becomes possible.
[0023] These and other objects, features, aspects and advantages of
the present invention will become apparent to those skilled in the
art from the following detailed description, which, taken in
conjunction with the annexed drawings, discloses a preferred
embodiment of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] Referring now to the attached drawings which form a part of
this original disclosure:
[0025] FIG. 1 is a schematic diagrammatical view of a conventional
vertical bag form-fill-seal packaging machine with devices in the
upstream and downstream processes;
[0026] FIG. 2 is a schematic diagrammatical view illustrating an
example of a production line for a downstream process for a bag
ejected from a conventional vertical bag form-fill-seal packaging
machine;
[0027] FIG. 3 is a schematic structural diagrammatical view of a
conventional vertical bag form-fill-seal packaging machine;
[0028] FIG. 4 is an elevational view of a vertical bag
form-fill-seal packaging machine in accordance with a first
embodiment of the present invention;
[0029] FIG. 5 is a control block diagrammatical view of the
vertical bag form-fill-seal packaging machine of FIG. 4;
[0030] FIG. 6 is an elevational view of the adjacent area of the
forced ejector of FIG. 4;
[0031] FIG. 7 is an elevational view of the adjacent area of the
forced ejector in accordance with a second embodiment of the
present invention;
[0032] FIG. 8 is a rear elevational view of the adjacent area of
the forced ejector of FIG.7;
[0033] FIG. 9 is an elevational view of the adjacent area of the
forced ejector in a variation of the second embodiment; and
[0034] FIG. 10 is an elevational view illustrating how the
belt-to-belt distance of the forced ejector is changed in another
variation of the second embodiment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
First Embodiment Compared to the Prior Art
[0035] A conventional measuring and bag forming/packaging line is
illustrated in FIG. 1, together with an example of devices in the
upstream and downstream processes. In this case, a product for
example, potato chips, is transferred by a supply conveyor 101 to a
position above the measuring unit 110. The product, once in the
measuring unit 110, is measured into a predetermined weight (or
quantity) and continuously discharged downward.
[0036] The product discharged from the measuring unit 110 moves
into a vertical bag form-fill-seal packaging machine 120 located
under the measuring unit 110. The vertical bag form-fill-seal
packaging machine 120 is a device for forming bags, and filling and
packing a product in the bags simultaneously. The bags containing
the product as a result of the packaging slides down the stationary
chute 129 provided with the vertical bag form-fill-seal packaging
machine 120, and are loaded onto the transfer conveyor 130. The
transfer conveyor 130 transfers the bags continuously discharged
there to a weight checker 140 in the downstream process.
[0037] If bags need to be continuously packed in carton boxes, the
bags are transferred from the transfer conveyor 130 to the weight
checker 140 and a sealing checker 150 as shown in FIG. 2. The bags
subjected to the weight and sealing checks here go through a
directing unit 160 and a posture adjustment unit 170 so that they
are sent to a boxing unit 180 in a file or files.
[0038] The boxing unit 180 is provided with a handling mechanism
181 holding the bags through suction, to pack the bags B into a
carton box. The carton box in which the bags B are packed is
transferred via a carton box transferring unit 190 to a box-sealing
unit and a labeling unit (not shown).
[0039] FIG. 3 shows the major structure of a conventional vertical
bag form-fill-seal packaging machine 120, the so-called vertical
pillow packaging machine. In the vertical bag form-fill-seal
packaging machine 120, sheet-like film Fm drawn from a roll of film
128 (see FIG. 1) is formed into a tubular shape through a former
121 and a tube 122 and fed downward by a pull-down belt mechanism
125. The overlapped vertical ends of the tubular film Fmc is
heat-sealed by a vertical sealing mechanism 123. When the measured
product fills the tubular film Fmc through the tube 122, the
transverse sealing mechanism 124 provided under the tube 122
performs transverse sealing in the area that will become the top of
the bag preceding and the bottom of the following bag. Concurrently
with the transverse sealing, the center of the transversely sealed
part is cut by a cutter built in the transverse sealing mechanism
124. The bags thus cut slide down on the stationary chute 129
provided under the transverse sealing mechanism 124, and then
transferred on a transfer conveyor 130 to the devices in the
downstream processes.
[0040] Overall Structure
[0041] A vertical bag form-fill-seal packaging machine in
accordance with the first embodiment of the present invention is
described below.
[0042] FIG. 4 shows a vertical bag form-fill-seal packaging machine
1, including a forced ejector 6 in accordance with a first
embodiment of the present invention. The vertical bag
form-fill-seal packaging machine 1 is a machine for packing a
product such as food for example, potato chips into bags, mainly
including a bag-forming/packaging section 5, a film supply unit 4,
and a forced ejector 6. The bag forming/packaging section 5 is a
main region for packing the product into bags. The film supply unit
4 supplies the bag-forming/packaging section 5 with the film that
ultimately becomes bags. The forced ejector 6 forcibly ejects
downward the bags formed by the bag-forming/packaging section 5. An
operation switch 7 (see FIG. 5) is provided at the front of the
vertical bag form-fill-seal packaging machine 1. A liquid-crystal
display 8 for showing the status of the operation is provided where
the operator manipulating the operation switch can visually check
operations. The control unit 20 shown in FIG. 5 controls the
operation of each of the drive units for the vertical bag
form-fill-seal packaging machine 1 and displays various data on the
liquid-crystal display 8 based on the input from the operation
switch 7.
[0043] A Structure of the Film Supply Unit
[0044] Referring to FIG. 4, the film supply unit 4 supplies
sheet-like film to a forming mechanism 13 in the
bag-forming/packaging section 5 that is to be described later. A
roll of film is set on the film supply unit 4 so that the film Fm
is unreeled from the roll.
[0045] A Structure of the Bag-Forming/Packaging Section
[0046] As shown in FIG. 4, the bag-forming/packaging section 5
includes the forming mechanism 13, a pull-down belt mechanism 14, a
vertical sealing mechanism 15, and a transverse sealing mechanism
17. The forming mechanism forms the film Fm that is fed in as a
sheet into a tubular shape. The pull-down belt mechanism 14
transfers the tubular-shaped film (hereinafter called "tubular film
Fmc") downward. The vertical sealing mechanism 15 vertically seals
the overlapped part of the tubular film Fmc. The transverse sealing
mechanism 17 transversely seals the tubular film Fmc to close the
top and bottom of each of the bags.
[0047] As shown in FIG. 4, the forming mechanism 13 has a tube 31
and a former 32. The tube 31 is a cylindrical member with its top
and bottom ends open. The tube 31 is made integral with the former
32 through a bracket. Measured items such as potato chips are put
into the open top end of the tube 31 from the measuring unit 11.
The former 32 is provided in such a manner that it surrounds the
tube 31. The shape of the former 32 is such that allows the
sheet-like film Fm fed from the film supply unit 4 to be formed
into a tubular shape when it passes between the former 32 and the
tube 31. The pull-down belt mechanism 14 is a mechanism for sucking
the film Fm wound on the tube 31 to pick it up and transfer it
downward. The pull-down belt mechanism mainly includes a driver
roller 41 and a driven roller 42, as well as a suction belt 43. The
vertical sealing mechanism 15 vertically seals the overlapped part
of the film Fm wound on the tube 31 by heating it while pressing it
against the tube 31 at a predetermined pressure. The vertical
sealing mechanism 15 has a heater and a heater belt that contacts
the overlapped part of the film Fm when heated by the heater.
[0048] The transverse sealing mechanism 17 is provided beneath the
forming mechanism 13, the pull-down belt mechanism 14, and the
vertical sealing mechanism 15. As shown in FIG. 6, the transverse
sealing mechanism 17 has a pair of symmetrical sealing jaws. The
two sealing jaws 17a, each of which turns in the shape of the
letter "D", leaving tracks T that are symmetrical to each other.
The sealing jaws 17a mate with each other when the tubular film Fmc
is ready to be transversely sealed. The transverse sealing
mechanism 17 has a cutter not shown in the drawing. The cutter
separates the bag from the tubular film Fmc that follows the bag at
the center of the part sealed by the sealing jaws 17a. The
transverse sealing mechanism 17 crimps the part to be transversely
sealed by sandwiching the tubular film Fmc between the sealing jaws
17a, a process that requires heat in addition to pressure.
Therefore, in order to heat the mating surfaces of the sealing jaws
17a that contact the tubular film Fmc, a heater is provided in the
each of the sealing jaws 17a, and a thermocouple is attached
thereto as well.
[0049] A Structure of the Forced Ejector
[0050] The forced ejector 6 mainly includes an endless belt 61, a
driver roller 62, a driven roller 63, and an AC servo motor 64. The
servo motor 64 turns the driver roller 62 and provides super-fine
turning control. The servo motor 64 is controlled by the control
unit 20 as shown in FIG. 5. As shown in FIG. 6, the belt 61 is
inclined so that the bag B moves diagonally downward. Still
referring to FIG. 6, the forced ejector 6 is positioned at a height
that enables the bottom of the bag B to contact with the upper side
of the belt 61 when the bag B is separated by the cutter provided
in the sealing jaws 17a. If the forced ejector 6 is at a position
higher than this, the belt 61 will thrust the bag B upward before
the transverse sealing is completed, resulting in a poor transverse
sealing. Conversely, if the forced ejector 6 is located too low,
the falling distance to the point where the separated bag B
contacts the belt 61 becomes too long, thus causing the bag B to
bounce on the belt 61 and deteriorating the stability of the
posture of the bag B.
[0051] A Structure of the Control Unit
[0052] As shown in FIG. 5, the control unit 20 is connected with
the film supply unit 4, bag-forming packaging sections 5, and
forced ejector 6 of the vertical bag form-fill-seal packaging
machine 1 to control the operation of each of the drive units.
First, the control unit 20 controls the rotating speed of the
sealing jaws 17a of the transverse sealing mechanism 17 as well as
the traveling speed of belt 61 of the forced ejector 6 according to
the downward feeding speed of the tubular film Fmc on the pull-down
belt mechanism 14. In controlling the forced ejector 6, the
rotating speed of the servo motor 64 is controlled according to the
feeding speed of the tubular film Fmc, i.e. the
bag-forming/packaging section 5 bag-forming capacity, to change the
ejection speed of the bag B (the traveling speed of the belt 61) at
the forced ejector 6. In this production line, an AC servo motor
131 is employed as a driving power source for the transfer conveyor
130. The servo motor 131 is controlled according to the data on the
ejecting speed of the forced ejector 6 and the bag ejection time
interval that are output from the control unit 20. The controlling
of the servo motor 64 for the forced ejector 6 and the servo motor
131 for driving the transfer conveyor 130 may be carried out by
changing the rotating speed to adjust the ejection interval between
the bags B, or by performing an intermittent driving to repeat
ON/OFF switching of operations to adjust the bags B' ejection
interval.
[0053] Further, the control unit 20 has an external output terminal
21, which can send the data on the bags B ejecting speed and bag
ejection time interval to the transfer conveyor 130 and other
devices in the downstream process (the weight checker 140, the
sealing checker 150, the boxing unit 180, and the like shown in
FIG. 2). In the control unit 20, a memory storage unit such as a
hard disc is also provided. Data on the shape, dimensions,
material, volume, and the like for each set of the bags are stored
in the memory storage unit, and the control patterns for each of
the drive units, including the appropriate controlling pattern for
the transfer speed of the forced ejector 6, are preset.
[0054] An Operation of the Vertical Bag Form-Fill-Seal Packaging
Machine
[0055] An operation of the vertical bag form-fill-seal packaging
machine 1 is described below.
[0056] Referring to FIG. 4, the sheet-like film Fm fed from the
film supply unit 4 to the forming mechanism 13 moves through the
former 32 and is wound on the tube 31. The sheet-like film Fm is
shaped in a tubular form and transferred, in this condition,
downward by being carried on the pull-down belt mechanism 14. When
wound on the tube 31, the film Fm has both ends overlapped on its
circumference. The overlapped part is to be vertically sealed by
the vertical sealing mechanism 15. The tubular film Fmc, now in a
cylindrical form as a result of the vertical sealing, moves out of
the tube 31 and down to the transverse sealing mechanism 17. At
this point, the position of the tubular film Fmc is in the area
indicated by the double-dot dash line in FIG. 4. Now, concurrently
with the travel of the tubular film Fmc, a mass of items, for
example, potato chips, falls from the measuring unit 110 via the
tube 31. At the transverse sealing mechanism 17, the bottom and the
top of the bag are transversely sealed, in sequence, with the
potato chips present in the tubular film Fmc. In the process of
transverse sealing by the transverse sealing mechanism 17, the
cutting process by the cutter provided in the sealing jaws 17a is
carried out concurrently as shown in FIG. 6. The cutter cuts the
approximate center of the transversely sealed part. Thus, as seen
in FIG. 4, the bag B is separated from the tubular film Fmc that
follows, and contacts the upper part of the belt 61 of the forced
ejector 6 and is forcibly carried diagonally downward according to
the turn of the belt 61.
[0057] In this process, if the bag B contacts the belt 61 at a
speed lower than the traveling speed of the belt 61, the bags B may
be bridged and tip forward. If the traveling speed of the belt 61
is substantially higher than the falling speed of the bag B, the
belt surface may not be able to catch the bag B. Therefore, the
traveling speed of the belt 61 is set equivalent to or a little
higher than the falling speed of the bag B. The maximum value of
this speed setting varies with the materials of the belt 61, the
film Fm, and the weight of the filled bag B. Therefore, the control
unit 20 considers these conditions in controlling the rotating
speed of the servo motor 64 to adjust the traveling speed of the
belt 61.
[0058] In setting a specific traveling speed for the belt 61, the
distance between the transverse sealing mechanism 17 and the belt
61, the falling speed of the bag B upon separation, gravitational
acceleration, and the like are used as the bases for
calculation.
[0059] The vertical bag form-fill-seal packaging machine, in
accordance with the first embodiment of the present invention, has
the following features:
[0060] The vertical bag form-fill-seal packaging machine 1 is
provided with the forced ejector 6 instead of a conventional
stationary chute 129 as seen in FIG. 3. Thus, variation of the
ejection pitch and the postures of the bag B ejected onto the
transfer conveyor 130 is prevented. With a conventional stationary
chute, on which frictional resistance is applied when the bag B
slides down or the impact is caused when falling, there is a high
possibility that the ejection pitch and the posture of the bag B
may become uneven. By using the forced ejector 6, the belt 61 is
allowed to contact with the bag B so that the bag B, together with
the belt 61, can be forcibly moved through the turn of the driver
roller 62, thereby preventing the variation of the pitch and the
posture of the bag as shown in FIG. 4.
[0061] In the vertical bag form-fill-seal packaging machine 1, the
belt 61 is provided in a slanted manner instead of vertically, to
ensure that the bag B separated from the tubular film Fmc contacts
the belt 61. Also, the incline of the belt 61 is such that the bag
B moves diagonally downward, thus reducing the impact that may be
caused when the bag B contacts with the belt 61, as well as
minimizing the change in the posture of the bag B. This also
reduces the problem that the bag B may be transferred in a stand-up
posture. As shown in FIG. 6, the incline of the belt 61 also
contributes to a reduction in the impact that may be caused when
the bag B moves from the belt 61 to the transfer conveyor 130.
[0062] Referring now to FIG. 5 in the vertical bag form-fill-seal
packaging machine 1, the control unit 20 takes control of linking
the bag-forming capacity of the bag-forming/packaging section 5
with the ejection (traveling) speed of the bag B by the forced
ejector 6, thereby enabling the pitch and the ejection time
interval of the bag B ejected by the forced ejector 6 onto the
transfer conveyor 130 in the downstream process to be set to
predetermined values. Even with the bag-forming capacity varied
between low speed (low throughput) and high speed (high
throughput), the pitch between the bags B to be ejected and the
ejection time interval between the bags B can be adjusted to suit
the external devices of the downstream processes such as the weight
checker 140, the sealing checker 150, and the boxing unit 180 by
controlling the servo motor 64 for the forced ejector 6 to change
the ejecting speed of the bag B.
[0063] In the vertical bag form-fill-seal packaging machine 1 in
accordance with the first embodiment of the present invention, the
AC servo motor 131 is employed as a driving power source for the
transfer conveyor 130, to control the transferring speed of the
transfer conveyor 130 according to the ejecting speed (traveling
speed) and the ejection time interval for the bag B at the forced
ejector 6. Therefore, even in high-speed forming of the bag B with
an improved capacity of the vertical bag form-fill-seal packaging
machine 1, the transfer of the bag B from the bag-forming/packaging
section 5 to the forced ejector 6 and from the forced ejector 6 to
the transfer conveyor 130 become smooth by synchronizing the
ejecting speed of the forced ejector 6 and the transfer conveyor
130 to aforesaid speeds, thus preventing the deterioration of the
posture and the pitch of the bag B.
[0064] The control unit 20 of the vertical bag form-fill-seal
packaging machine 1 controls the transfer speed of the transfer
conveyor 130 according to the ejecting speed of the forced ejector
6. The control unit 20 also provides data such as the ejecting
speed, the ejection time interval, ejection pitch (interval between
the bag tops or the bags themselves, bag length, and the like) at
the forced ejector 6 to the external equipment in the downstream
process via the external output terminal 121. This enables process
control at the external equipment (at a device in the downstream
process) such as the weight checker 140, the sealing checker 150,
and boxing unit 180 that takes advantage of aforesaid data.
[0065] For example, the external equipment that has received the
data on the ejection time interval and the ejection pitch
(bag-to-bag distance) sets the processing speed and the
transferring speed according to the ejection time interval; if the
ejection pitch is too small, the transferring speed is increased so
that the bag-to-bag interval is increased. The ejecting speed can
be obtained from the following formula:
(Bag length+bag-to-bag distance)/(ejection time interval).
[0066] The bag-to-bag distance can be obtained from the following
formula:
(Ejecting speed).times.(ejection time interval)-(bag length).
[0067] The external equipment can be controlled properly for
processing with the data on (ejection time interval); (bag length);
and (ejecting speed) or (bag-to-bag distance). Some variations of
the first embodiment are described below as examples.
[0068] (1) In the aforesaid embodiment, the forced ejector 6
including the belt 61, the driver roller 62, driven roller 63, and
the servo motor 64 is incorporated in the vertical bag
form-fill-seal packaging machine 1. The ejector may be provided as
a device independent from the vertical bag form-fill-seal packaging
machine. In such a case, the forced ejector 6 including the belt
61, the driver roller 62, driven roller 63, and the servo motor 64
should be provided beneath the vertical bag form-fill-seal
packaging machine. In this way, the forced ejector can be
retrofitted to a conventional vertical bag form-fill-seal packaging
machine after the removal of the stationary chute.
[0069] (2) In the first embodiment described so far, the forced
ejector 6 includes the belt 61 that contacts the bag B and the
driver roller 62 or the like that lets the belt 61 travel. It is
also possible to use a mechanism for forcibly feeding the bag B
without touching the bag B to make the forced ejector 6. For
example, a vacuuming mechanism for sucking to draw the bag B
separated by the transverse sealing mechanism 17 may be provided
below the transverse sealing mechanism 17. It is also possible to
provide a mechanism for generating an air flow around the bag B to
be separated.
[0070] (3) In the aforesaid first embodiment, the transferring
speed of the transfer conveyor 130 is linked with the vertical bag
form-fill-seal packaging machine 1 by utilizing the external output
terminal 21 of the control unit 20. The transfer conveyor 130 may
also be incorporated into the vertical bag form-fill-seal packaging
machine 1 for the purpose of controlling the transferring speed and
ejection time interval in the same manner of handling as do the
bag-forming/packaging section 5 and the forced ejector 6.
[0071] (4) On the belt 61 and the belt for the transfer conveyor
130 of the aforesaid first embodiment, a guide bar may be provided
so that only one of the bags B fits in each space created by the
guide bar. By providing such a guide bar at an appropriate interval
on the belt, the uniformity of the ejection interval between the
bags B increases. It is preferable to provide the guide bar so that
it is orthogonal to the direction of the belt transfer, to prevent
the positional shifting of the bag B on the belt.
[0072] (5) As the belt 61 and the belt for the transfer conveyor
130 of the aforesaid first embodiment, a plurality of round belts
or a vacuum suction belt also may be employed.
Second Embodiment
[0073] Referring mainly to FIG. 7, vertical bag form-fill-seal
packaging machine, in accordance with a second embodiment of the
present invention, is a machine for packing a product such as food
(potato chips in this case) into bags. The machine mainly includes
a bag-forming/packaging section, film supply unit, a forced ejector
206, and a cooling section 9. The structure of the film supply unit
and the bag-forming/packaging section are the same as those in the
first embodiment. The bag-forming/packaging section is a main
region for packing the product into bags, a film supply unit 4
supplies the bag-forming/packaging section with the film that
ultimately becomes bags. The forced ejector 206 forcibly ejects
downward the bags formed by the bag-forming/packaging section. The
cooling section 9 forcibly cools the bags formed by the
bag-forming/packaging section. An operation switch, a
liquid-crystal display, and a control unit are also provided in the
same manner as in the first embodiment of the present
invention.
[0074] Structure of the Forced Ejector
[0075] As shown in FIG. 7, the forced ejector 206 mainly includes
endless belts 261a & 261b, driver rollers 262a & 262b,
driven rollers 263a & 263b, and an AC servo motor. The servo
motor for turning the driver rollers 262a & 262b is a motor
capable of providing extremely fine turning control, and is
controlled by the control unit (not shown). The belt 261a is placed
on one driver roller 262a and three driven rollers 263a so that it
travels in a manner to move the bag B downward according to the
rotation of the driver roller 262a. The belt 261b is placed on one
driver roller 262b and three driven rollers 263b so that it travels
in a manner to move the bag B downward according to the rotation of
the driver roller 262b.
[0076] As shown in FIG. 8, the belt 261b is provided with openings
269 at a uniform interval to prevent its interference with the
sealing jaws 17a. Also, the driver roller 262b and the driven
rollers 263b are provided so that they are placed underneath the
both ends of the belts 261b to prevent their interference with the
sealing jaws 17a as seen in FIG. 7. The belt 261a is similarly
constructed. As seen in FIG. 7, the belt 261b extends downward
farther than the belt 261a, to assist in the loading of the bag B
onto the transfer conveyor 130.
[0077] A part of the transfer passage formed between the belts 261a
& 261b may be inclined between the vertical area and the
horizontal area so that the direction for transferring the bag B
changes from vertical to horizontal as the bag moves through the
passage. The rotation of the driver rollers 262a & 262b is
controlled so that the belts 261a & 261b travel at a constant
speed.
[0078] Structure of the Cooling Section
[0079] The cooling section 9, which includes two air sprayers 9a,
is provided inside the loops of the endless belts 261a & 261b
to spray air through the opening in the belts 261a & 261b to
the bag B that is fed downward by the belts 261a & 261b. The
ON/OFF switching and the spraying volume of the air sprayers 9a are
maintained by the control unit.
[0080] Operation of the Vertical Bag Form-Fill-Seal Packaging
Machine
[0081] An operation of the vertical bag form-fill-seal packaging
machine in accordance with the second embodiment is described
below.
[0082] As with the first embodiment, the sheet-like film fed from
the film supply unit to the forming mechanism moves through the
former and is wound on tube. The sheet-like film is shaped in a
tubular form and transferred, in this condition, downward by being
carried on the pull-down belt mechanism. When wound on the tube,
the film has both ends overlapped on its circumference, and the
overlapped part is to be vertically sealed by the vertical sealing
mechanism.
[0083] The tubular film Fmc, now in a cylindrical form as a result
of the vertical sealing, moves out of the tube and down to the
transverse sealing mechanism. At this point, concurrently with the
travel of the tubular film Fmc, a mass of items, for example potato
chips falls from the measuring unit via the tube. Now, through the
transverse sealing mechanism, the bottom and the top of the bag are
transversely sealed in sequence, with the items, for example potato
chips present in the tubular film Fmc.
[0084] As seen in FIG. 7, in the process of transverse sealing by
the transverse sealing mechanism 17, the cutting process by the
cutter provided in the sealing jaws 17a is carried out
concurrently. The cutter cuts the approximate center of the
transversely sealed part. Also, prior to the process of transverse
sealing, the bag B (yet to be transversely sealed) is held by the
belts 261a & 261b that come into contact with the bag on both
sides, and forcibly fed downward. The feeding speed is controlled
by the control unit to be synchronous with the feeding speed on the
pull-down belt mechanism and the traveling speed of the sealing
jaws 17a.
[0085] The bag B that has moved out of the transverse sealing
mechanism 17 is subjected to the air sprayed from the cooling
section 9 while it is held by the belts 261a & 261b of the
forced ejector 206 in a sandwiched manner and being transferred
downward. This cools the heat-sealed part, thus increasing its
bonding strength before the bag B is loaded on the transfer
conveyor 130.
[0086] As shown in FIG. 7, the bag B that has moved out of the
cooling section 9 leaves the belts 261a & 261b and is loaded on
the transfer conveyor 130 and carried thereon to devices such as
the weight checker in a downstream process. The vertical bag
form-fill-seal packaging machine in accordance with the second
embodiment, of the present invention has the following
features:
[0087] By turning the belts 261a & 261b through the driver
rollers 262a & 262b to move the bag B downward while holding
the bag B with the two belts 261a & 261b of the forced ejector
206 in a sandwiched manner, the bag B is forcibly moved to the
transfer conveyor 130 in the second embodiment. Thus, by holding
the bag B with the two belts 261a & 261b in a sandwiched
manner, problems such as slippage of the belts 261a & 261b
resulting in a variation of the pitch of the bags B to be ejected
can be reduced.
[0088] Taking advantage of the structure for holding bag B with the
two belts 261a & 261b in a sandwiched manner, cooling air is
sprayed upon bag B thus held to ensure the bonding strength of the
heat-sealed part of the formed bag B.
[0089] In a conventional machine, the sealed part (particularly the
transversely sealed part) of the bag B may be sent to the device in
a downstream process without sufficiently being cooled down, or air
is blown on the bag B on a transfer conveyor with a cooling fan.
However, in blowing wind upon the bag B on the transfer conveyor,
there is a need to restrict the air volume so that the position of
the bag B will not be shifted, which makes it difficult to achieve
a sufficient cooling effect in a high-speed operation.
[0090] To counter this problem, the second embodiment achieves a
condition in which the posture hardly will be affected, even with
air-spray cooling, through the method of holding the bag B with the
two belts 261a & 261b in a sandwiched manner. It employs a
structure in which air is sprayed with the air sprayer 9a to the
bag held by the belts 261a & 261b in a sandwiched manner. This
allows effective cooling of the heat-sealed part of the formed bag
B, thus reducing bag breakage even with high-speed ejection of the
bag B. Some variations of the second embodiment are described below
as examples.
[0091] (1) In the aforesaid second embodiment, the bag B that has
left the belts 261a & 261b moves almost vertically until it
hits against the transfer conveyor 130 as shown in FIG. 7. In a
high-speed operation, the impact caused when the bag B comes up
against the transfer conveyor 130 may be great. To reduce the
impact, a forced ejector 306 as shown in FIG. 9 may be employed
instead of the forced ejector 206.
[0092] The forced ejector 306 shown in FIG. 9 includes endless
belts 361a & 361b, driver rollers 362a & 362b, driven
rollers 363a & 363b, a direction-changing driven roller 364,
and an AC servo motor. The servo motor for turning the driver
rollers 362a & 362b provides extremely fine turning control,
and is controlled by a control unit. The belt 361a is placed on one
driver roller 362a and three driven rollers 363a so that it travels
in a manner to move the bag B downward according to the rotation of
the driver roller 362a. The belt 361b is placed on one driver
roller 362b, three driven rollers 363b, and the direction-changing
driven roller 364 so that it travels in a manner to move the bag B
downward according to the rotation of the driver roller 362b.
[0093] The belts 361a & 361b are provided with openings at a
uniform interval to prevent its interference with the sealing jaws
17a. The driver rollers 362a & 362b, the driven rollers 363a
& 363b, and the direction-changing driven roller 364 are
provided so that they come under the both ends of the belts 361a
& 361b to prevent their interference with the sealing jaws 17a.
The rollers 362a, 362b, 363a, 363b, & 364 are provided in the
positions shown in FIG. 9, so that the bag B, after leaving the
cooling section 9, moves in a different direction, changing from
vertical to horizontal, toward the transfer conveyor 130. The
rotation of the driver rollers 362a & 362b is controlled so
that the belts 361a & 361b travel at a constant speed. Thus,
the structure of the forced ejector 306 in the second embodiment is
made to allow, in its lower portion, the bag B to move toward the
horizontal direction; i.e. the surface on which the bag B below the
belt 361b comes into contact is inclined so that the bag is ejected
horizontally onto the transfer conveyor 130. This significantly
reduces the impact that may be caused when the bag B is loaded onto
the transfer conveyor 130
[0094] (2) Referring to FIG. 7, the forced ejector 206 in the
second embodiment may further be provided with a function to
optimize the volume of the gas to be filled in the bag B. In such a
case, the distance between the belts 261a & 261b of the forced
ejector 206 is made variable by a means for changing the
belt-to-belt distance. The distance between the belts 261a &
261b is also controlled by the control unit 20 according to the
type of the bag B and the volume of the gas required to fill the
bag.
[0095] A possible example of the means for changing the
belt-to-belt distance is a mechanism that moves a first unit having
the belt 261a, the driver roller 262a, and the driven roller 263a,
and a second unit having the belt 261b, the driver roller 262b, and
the driven roller 263b to the right or left by using motorized ball
screws and a servo motor. As shown in FIG. 10, this makes it
possible to shift each element of the forced ejector 206 from the
position shown with the solid line to the position shown with the
broken line, and to change the distance between the belts 261a
& 261b into any value with the control unit. Then, by adjusting
the distance between the belts 261a & 261b while setting the
volume of the gas to be filled which is sprayed from above the
tubular film Fmc somewhat higher, the volume of the gas to be
filled in the bag B, or the volume of the bag B, is made
uniform.
[0096] In a conventional machine, the volume of the gas to be
filled is adjusted by varying the period of the spraying time, for
example. However, if the gas supply sources are centralized in a
large-scale plant, the supply pressure of the gas supply source
often varies, thus making it difficult to prevent variation in the
volume of gas to be filled. A variation in the volume of gas to be
filled results in a variation in the volume of the bag B, leading
to a problem at the boxing unit in a downstream process. The boxing
unit packs a specified number of the bags B into carton boxes by
the use of a handling mechanism that utilizes suction or the like.
If the volume of the bag B is not constant as described above, the
following problems may occur: mishandling, bag breakage, a gap in
the carton box after the specified number of the bags B are placed
inside. Thus problems during transportation, and a failure to pack
the specified number of the bags B in the carton box may
result.
[0097] To counter the above, this variation of the second
embodiment, by taking advantage of structures for holding the bag B
with the two belts 261a & 261b in a sandwiched manner and by
adjusting the distance between the two belts 261a & 261b,
enables the controlling of the volume of the gas to be filled in
the formed bag B, thus achieving uniformity of the volume of the
bag B. This allows the bag B, almost uniform in volume, to be
supplied to the devices in a downstream process, which should
reduce the incidence of problems in the devices during the
downstream process.
[0098] The terms of degree such as "substantially", "about" and
"approximately" as used herein mean a reasonable amount of
deviation of the modified term such that the end result is not
significantly changed. These terms should be construed as including
a deviation of at least .+-.5% of the modified term if this
deviation would not negate the meaning of the word it modifies.
[0099] While only selected embodiments have been chosen to
illustrate the present invention, it will be apparent to those
skilled in the art from this disclosure that various changes and
modifications can be made herein without departing from the scope
of the invention as defined in the appended claims. Furthermore,
the foregoing description of the embodiments according to the
present invention are provided for illustration only, and not for
the purpose of limiting the invention as defined by the appended
claims and their equivalents.
* * * * *