U.S. patent number 3,855,907 [Application Number 05/361,537] was granted by the patent office on 1974-12-24 for method and machine for forming flat bottom bags having side gussets.
This patent grant is currently assigned to Rexham Corporation. Invention is credited to Kenneth R. Johnson, Robert F. Lense.
United States Patent |
3,855,907 |
Johnson , et al. |
December 24, 1974 |
METHOD AND MACHINE FOR FORMING FLAT BOTTOM BAGS HAVING SIDE
GUSSETS
Abstract
The machine first makes a strip of side gusset bags having two
inwardly tucked panels forming each of the side gussets, the bags
being interconnected with each other by cross-seals. A transfer
splitter receives each leading bag at a pick off station prior to
and during severing of the bag from the strip. The transfer
splitter is operable to swing the severed bag into an upright
position while keeping the gusset panels separated from each other.
Grippers carried by a conveyor receive the bag from the transfer
splitter and clamp the bag for step-by-step movement with the
conveyor while keeping the panels separated from each other so as
to permit subsequent expansion of the gussets to open the bag as it
remains clamped to the conveyor. The lower end portion of the bag
is folded upwardly and sealed to the one side of the bag to
complete formation of the bag prior to the bag being opened and
filled with a charge of product.
Inventors: |
Johnson; Kenneth R. (Rockford,
IL), Lense; Robert F. (Rockford, IL) |
Assignee: |
Rexham Corporation (New York,
NY)
|
Family
ID: |
23422435 |
Appl.
No.: |
05/361,537 |
Filed: |
May 18, 1973 |
Current U.S.
Class: |
493/235; 53/455;
53/480; 53/562; 53/469; 53/482; 53/570 |
Current CPC
Class: |
B65B
43/04 (20130101); B31B 70/266 (20170801); B31B
2150/003 (20170801); B31B 2155/0012 (20170801); B31B
2160/106 (20170801); B31B 2160/10 (20170801); B31B
2150/00 (20170801); B31B 2150/0012 (20170801); B31B
2160/20 (20170801); B31B 2155/00 (20170801); B31B
70/36 (20170801) |
Current International
Class: |
B31B
23/00 (20060101); B31B 37/00 (20060101); B65B
43/00 (20060101); B65B 43/04 (20060101); B31b
033/74 () |
Field of
Search: |
;93/14,16,17,18,19,21,22,24,25,26,35R,35SB,8R ;53/29,183 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Lake; Roy
Assistant Examiner: Coan; James F.
Attorney, Agent or Firm: Wolfe, Hubbard, Leydig, Voit &
Osann, Ltd.
Claims
We claim as our invention:
1. A method of forming flat bottom, side gusset bags from a strip
of interconnected bags, said strip having cross-seals connecting
said bags together and having side gussets along opposite margins
and each defined by two inwardly tucked panels which face one
another, said method comprising the steps of, advancing said strip
along a predetermined path, guiding the leading bag in said strip
into a pick off station, separating the two panels of each of the
gussets from each other as the bag is moved into said station,
severing the leading bag from said strip adjacent said station
along the edge of one of said cross-seals to leave the severed bag
with one end closed by one of said cross-seals and with the other
end unsealed, swinging said severed bag from said pick off station
onto a conveyor, keeping each of the two panels separated from each
other as said bag is swung from said pick off station onto said
conveyor, clamping said bag on said conveyor, maintaining each of
said two panels separated from each other as said bag is clamped to
said conveyor so as to permit subsequent expansion of said gussets
to open said bag as the latter remains clamped to the conveyor,
advancing said conveyor to carry said bag along a continuation of
said path, folding a portion of the sealed end of the bag along one
side of the bag while the bag is clamped to said conveyor, and
sealing said portion against the side of the bag to complete
formation of the sealed end of the bag prior to opening and filling
of the bag.
2. A method of forming side gusset bags from a strip of
interconnected bags, said strip having cross-seals connecting said
bags together and having side gussets along opposite margins and
each defined by two inwardly tucked panels which face one another,
said method comprising the steps of, advancing said strip
step-by-step along a horizontal path with the bags disposed in
horizontal positions, guiding the leading bag in said strip into a
pick off station, separating the two panels of each of the gussets
from each other as the bag is moved into said station, severing the
leading bag from said strip adjacent said pick off station along
the edge of one of said cross-seals to leave the severed bag with
one end closed by one of said cross-seals and with the other end
unsealed, swinging said severed bag from said pick off station into
an upright position on a conveyor while keeping each of the two
panels separated from each other, gripping only one of the panels
in each gusset to clamp the bag on the conveyor while still keeping
the two panels in each gusset separated from each other to permit
subsequent expansion of said gussets to open said bag as the latter
remains clamped to the conveyor, advancing said conveyor
step-by-step to carry said bag along a horizontal path with the bag
in an upright position, applying adhesive across the bag adjacent
the sealed end thereof, folding a portion of the sealed end of the
bag upwardly along one side of the bag, and pressing said folded
portion against the side of the bag to cause the adhesive to seal
the folded portion to the side of the bag to complete formation of
the bag prior to opening and filling of the bag.
3. A method of forming side gusset bags as defined by claim 2
further including the steps of opening each bag after completing
the formation of the bottom of the bag, squaring the bottom of the
bag as the latter is opened, and filling the bag with a
product.
4. A method of forming side gusset bags as defined by claim 3
further including the steps of transferring the bag onto a second
conveyor, holding the bag for movement with said second conveyor,
unclamping said bag from said first conveyor after filling the bag,
advancing said second conveyor in timed relation with said first
conveyor, tucking the gussets toward each other adjacent the top of
said bag, and sealing together the upper end portion of the
opposite sides of said bag to close the bag.
5. A machine for forming side gusset bags from a strip of
interconnected bags, said strip having cross-seals connecting said
bags together and having side gussets along opposite margins and
each defined by two inwardly tucked panels which face one another,
said machine including means for advancing said strip step-by-step
along a predetermined path into a pick off station, a splitter
sandwiched between the two facing panels of each gusset and
operable to keep the panels separated as the leading bag is
advanced into the pick off station, a cutter adjacent said pick off
station and operable to sever the leading bag from said strip along
one edge of one of said cross-seals to leave the severed bag with
one end closed by one of said cross-seals and with the other end
unsealed, a transfer splitter receiving said leading bag at said
pick off station prior to cutting of the bag, said transfer
splitter being sandwiched between the two facing panels of each
gusset and being movable from said pick off station to swing the
severed bag into an upright position while keeping each of the two
panels separated from each other, a conveyor having one end located
adjacent said pick off station and operable to move said bag
step-by-step along a continuation of said path in timed relation
with the advancement of said strip, grippers carried by said
conveyor and operable to clamp said bag in its upright position for
movement with said conveyor, said grippers keeping each of said two
panels separated from each other so as to permit subsequent
expansion of said gussets to open said bag as the latter remains
clamped to said conveyor, means for folding a portion of the sealed
end of said bag upwardly against one side of the bag, and means for
sealing said folded portion to the side of the bag to complete
formation of the bag prior to opening and filling of the bag.
6. A machine as defined by claim 5 further including means for
applying adhesive across said bag adjacent the sealed end thereof
prior to folding said portion of the sealed end against the side of
the bag.
7. A machine as defined by claim 6 wherein said conveyor advances
said bag through an opening station and a filling station, a bag
opener located at said opening station, adapted to open said bag
and to square the bottom of the bag, a dispenser located at said
filling station and operable to deposit a charge of product into
said bag, and a second conveyor operable in timed relation with
said first conveyor for receiving said bag from said first conveyor
and holding said bag for advancement along a further continuation
of said path to be sealed closed.
Description
BACKGROUND OF THE INVENTION
This invention relates to a method and a machine for forming bags
from a continuous web of flexible material and for filling each of
the bags with a product. More particularly, the invention relates
to the manner in which the bags are transported as they are formed,
opened, filled and closed. Herein, the web is formed into a
continuous flat tube or strip having horizontal sides and inwardly
tucked opposite edge portions, each of the edge portions including
two facing panels which define an expandable gusset. Longitudinally
spaced cross-seals are formed across the tube so the tube defines a
strip of interconnected bags. The bags are severed from the leading
end portion of the strip by a cutter which slices through the strip
adjacent the trailing edge of each cross-seal so one end of the
newly formed bag is unsealed.
Thereafter, the bags are turned into upright positions with the
unsealed ends facing upwardly and then the bags are advanced in
spaced relation through a filling station to receive a measured
charge of product. Before being filled, the body of each bag is
expanded so as to unfold the side gussets and open the bag to
receive the product charge. After being filled, the bags are sealed
closed along their upper margins.
A machine of this general character is shown in our prior U.S. Pat.
No. 3,545,166 entitled Method and Machine for Forming and Filling
Bags.
SUMMARY OF THE INVENTION
The primary object of the present invention is to provide a new and
improved machine of the above general type which is adapted to
operate in a novel manner to form flat bottom side gusset bags of
the type in which a lower margin of each bag is folded upwardly and
sealed to one side thereof before the bag is opened to be filled. A
more detailed object is to adapt the foregoing machine in a manner
such that the bags are partially formed in a bag making section of
the machine while moving along a predetermined path and thereafter
are transferred to a conveyor for movement along a continuation of
the path through a filling station, the formation of the bottoms of
the bags being completed while being advanced by the conveyor and
before the bags are opened to receive the measured charge of
product.
A further object is to construct the machine so the two panels
forming each of the side gussets are kept separated from each other
as the bags are transferred from the bag making section of the
machine to the conveyor.
A still further object is to hold the bags in their upright
positions on the conveyor so that, without releasing the bags from
the conveyor, the formation of the bottoms of the bags may be
completed and thereafter the side gussets may be expanded to open
the bags for filling.
Another detailed object of the present invention resides in the
provision of a second conveyor adapted to receive the filled bags
from the first conveyor and to transport the filled bags through
successive stations where the upper margins of the bags are folded
together and sealed closed to complete the packaging operation.
The invention also resides in the provision of a unique transfer
splitter operable to move back and forth between a pick off station
adjacent the downstream side of the cutter and one end of the first
conveyor to swing the bags from their horizontal positions into
their upright positions while keeping the adjacent gusset panels
separated from each other. The invention is further characterized
by the provision of unique grippers which are carried by the first
conveyor and are operable to grasp the bags for movement therewith
without holding the gusset side panels together so the gussets may
be expanded to open the bags without releasing the grippers.
These and other objects and advantages of the present invention
will become more apparent from the following detailed description
when taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1a is a schematic perspective view of the bag forming portion
of a machine embodying the novel features of the present
invention.
FIG. 1b is a continuation of FIG. 1a and is a schematic view of the
bag-filling and bag-closing portion of the machine.
FIG. 2 is a perspective view of a bag after being formed, filled
and closed by the machine.
FIG. 3 is an enlarged cross-sectional view taken substantially
along line 3--3 of FIG. 1a.
FIG. 4 is an enlarged cross-sectional view taken substantially
along line 4--4 of FIG. 1a.
FIG. 5 is a fragmentary perspective view of a partially formed bag
made by the machine.
FIG. 6 is an enlarged fragmentary perspective view of a transfer
splitter for transporting partially formed bags from horizontal to
upright positions.
FIG. 7 is a fragmentary perspective view similar to FIG. 6, but
showing parts of the machine in moved positions.
FIG. 8 is an enlarged cross-sectional view taken substantially
along 8--8 of FIG. 7.
FIG. 9 is an enlarged fragmentary perspective view showing parts of
a flying splitter for guiding the partially formed bags onto the
transfer splitter.
FIG. 10 is an enlarged fragmentary perspective view schematically
showing parts of the machine for completing the formation of the
bottoms of the bags prior to the bags being completely opened.
FIG. 11 is an enlarged fragmentary cross-sectional view taken
substantially along line 11--11 of FIG. 10.
FIG. 12 is an enlarged schematic perspective view showing the
bag-opening, the bag-filling and the bag-closing stations of the
machine.
FIG. 13 is an enlarged fragmentary cross-sectional view taken
substantially along line 13--13 of FIG. 12.
FIG. 14 is a view similar to FIG. 13, but showing parts in moved
positions.
FIG. 15 is an enlarged schematic view showing the bag-closing and
bag-sealing stations of the machine.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
As shown in the drawings for purposes of illustration, the present
invention is embodied in a machine 20 particularly adapted for
forming, filling and closing side gusset bags 21 having flat
bottoms 22. As shown in FIGS. 2 and 3, each bag comprises two
opposing face-to-face sides 26 and 27 joined together along their
two side margins by gussets 33 and along their bottom margins by a
lower seal 51. The upper margins 163 of the sides are sealed
together to close the bag. In each completed, filled and closed
bag, the gussets are expanded and triangular portions 170 (FIG. 15)
of the top margins of each gusset and similar portions (not shown)
of the bottom margins of each gusset are disposed inwardly to shape
the bag as a block. More particularly, the lower seal 51 extends
across the bottom 22 of the bag between the gussets and each gusset
is defined by two adjacent side panels 42 joined together along a
fold line 28.
Basically, the machine 20 comprises a bag-making section 32 (FIG.
1a) with which the bags 21 are formed from a flexible web 24 of
heat sealable material such as foil, plastic or paper as the web is
advanced in a horizontal direction along a predetermined path.
Downstream from and disposed end-to-end with the bag making section
is a bag-fill section 38 (FIG. 1b) to which the newly formed bags
are transferred for filling and closing during advancement along an
extension of the path.
In the bag-making section 32, the web 24 which is heat sealable
along one side thereof is formed into a continuous strip 23 of
interconnected bags. To form the strip of bags, the web is advanced
intermittently past and is folded around a tube former 25 to bring
the opposite edge portions of the web into overlapping relation to
form the opposing sides 26 and 27, the latter side being
interrupted by a longitudinal seam 29 defined by the overlapped
edge portions of the web. As shown in FIG. 1a, the tube former
includes a forming wheel 30 under which the web feeds so opposite
edge portions of the web are dished upwardly. Upon leaving the
wheel, the web passes beneath and alongside a forming plate 31, the
dished edge portions being folded gradually around the plate and
into an overlapping relation to form the web into a flat tube with
the seam 29 facing upwardly.
To form the tube with the side gussets 33, the opposite edge
portions of the tube are tucked inwardly in a V-shape as shown in
FIG. 3. For this latter purpose, the forming plate 31 comprises a
narrow center section 34 sandwiched between upper and lower
sections 35 which are sider than the center section so as to define
elongated grooves 36 extending alog opposite side edges of the
plate. The upstream end of the plate is supported by a leg 37 (FIG.
1a) secured to the upper section 35 while the downstream end of the
plate is supported by two rollers 39 which are disposed on opposite
sides of the plate and extend laterally of the tube. As the web 24
is advanced beneath the forming plate, its longitudinal edge
portions are tucked into the grooves by elongated stationary
splitters 40 projecting inwardly into the grooves between the upper
and lower plate sections, each of the side gussets 33 thus being
formed with the panels 42 facing each other. Above the splitters
are four forming disks 41 which exert frictional forces on the web
tending to wrap the same gradually around the top of the plate.
Pressing fingers 43 are disposed between the pairs of disks and
overlie and hold the web as it passes between the disks.
Downstream of the disks 41, an electrically heated sealing bar 44
(see FIGS. 1a and 3) is brought downwardly into engagement with the
upper side 27 of the web or tube 24 along the seam 29 to seal
together the overlapping edge portions. After the seam has been
heat-sealed and the tube has been advanced through one step, the
newly formed seal is hardened by a cooling bar 45 which is
maintained at a low temperature. Herein, both the sealing bar and
the cooling bar are moved up and down to engage and release the
tube by pneumatic actuators 46 and 47 which are controlled in timed
relation with the advance of the tube.
In a similar manner, a heated cross-sealing bar 49 and a lateral
cooling bar 50 located downstream of the plate 31 are actuated to
pinch the opposite sides 26 and 27 of the tube 24 together to form
spaced cross-seals 51 (see FIGS. 1 and 5). In this way, the tube is
formed into the strip 23 of interconnected bags 21 which are
subsequently severed from each other. At the same time the
cross-seal is formed in each bag, the cross-sealing bar also forms
a slanted seal 52 between the lower margin of each panel 42 and the
adjacent side 26 or 27 of the bag, each slanted seal extending
upwardly and outwardly from the lower end of the fold line 28 to
the edge between the panel and the side of the bag. The space
between the two slanted seals on each gusset 33 defines the
triangular portion which is to be disposed inwardly on the bottom
margin of the gusset. In addition to cooling the hot cross-seal and
slanted seals in each bag, the cooling bar 50 also forms a crease
53 (FIG. 5) in the tube along the upstream edge of the cross-seal
when advanced against the bag so as to later facilitate folding of
the bottom margin upwardly along the side 27 of the bag.
Downstream of the cooling bar 50, mechanism in the form of two
horizontal drive rollers 54 (FIG. 1a) frictionally engages the
opposite sides 26 and 27 of the bags to advance the strip 23. The
rollers are rotated intermittently through precisely controlled
angular distances to feed the strip through steps exactly equal in
length to the length of the bags. Herein, the rollers are connected
to a motor 55 by a power train 56 operable to drive the rollers
intermittently in response to measured movement of the strip of
bags as detected by a photoelectric scanner 57 supported above the
bags.
A cutter 63 (FIG. 1a) in the cutting station 60 severs the leading
bag 21 in the strip 23 from the other bags by cutting the strip
alongside and just behind the trailing edge of each cross-seal 51
so one end of the bag is sealed by the cross-seal and the other end
of the bag is unsealed. Each bag, after being cut from the strip,
is turned into an upright position so the sealed end of the bag
forms a lower margin 64 (see FIG. 7) and the unsealed end of the
bag faces upwardly. Thereafter, a conveyor 65 advances the upright
bag in an edgewise direction step-by-step through a filling station
66 (see FIG. 1b). In this instance, the conveyor includes an
endless chain 67 traveling in a horizontal plane and trained around
sprockets 69 and 70, the sprocket 69 being positioned adjacent and
below the pick off station 61 such that one of the curved end runs
of the chain is spaced downstream of and beneath the horizontally
disposed bags cut from the strip 23 at the cutting station 60. A
Geneva mechanism 71 coupled to the sprocket 70 is driven by a cycle
shaft 72 and is timed to advance the chain intermittently at
approximately the same time the drive rollers 54 are advancing the
strip so both the chain and the drive rollers dwell during the same
intervals.
In accordance with the primary aspect of the present invention, the
machine 20 is adapted to operate in a novel manner so as to
complete formation of each of the bags 21 by folding the lower
margin 64 of the bag upwardly and sealing the margin to the side 27
of the bag as the latter is advanced along the fill section 38 of
the machine but before the bag is opened to be filled. For this
purpose, a unique transfer splitter 73 (FIG. 1b) swings each of the
partially formed bags from the pick off station 61 of the bag
making section 32 into an upright position of the conveyor 65 for
grippers 74 to clamp the bags for movement with the conveyor.
Advantageously, the transfer splitter keeps the two facing panels
42 in each gusset 33 separated from each other as the bag is swung
from the pick off station to the conveyor so the grippers can clamp
the bag along its edges to permit the lower margin of the bag to be
folded upwardly and sealed to the side of the bag while still
keeping the two panels in each gusset separated from each other.
This permits subsequent expansion of the gussets to open the bag
for receiving the product charge as the bag remains clamped to the
conveyor. Thus, with this arrangement, the machine 20 is adapted
for use in forming flat-bottom bags by completing formation of the
bottom 22 of the bag after the latter is transferred from the bag
making section of the machine.
In the present instance, the transfer splitter 73 is swung from the
pick off station 61 to carry each bag 21 to the conveyor 65 during
the dwell period and includes spaced parallel blades 75 (see FIGS.
6 and 7) supported on pivot arms 76 by links 77. The blades fit
between the gusset panels 42 along opposite edges of the bag, and
suction cups 79 help hold the bag on the blades as the splitter
swings toward the conveyor. Herein, a flying splitter 80 guides the
end bag of the strip 23 from the downstream ends of the stationary
splitters 40, through the cutting station 60 and into the pick off
station. Upon reaching the pick off station, the flying splitter
abuts the transfer splitter 73 (see FIG. 9) so that, as the strip
advances further into the pick off station, the panels 42 slide
telescopically onto the blades so the latter keep the panels
separated from each other.
Prior to severing the end bag 21 from the strip 23, the flying
splitter 80 is retracted relative to the strip, back upstream of
the cutter 63 and into position to guide the next bag into the pick
off station 61 during the next advance of the strip. Herein, the
flying splitter is reciprocated by a fluid-actuated cylinder 81
with each advance step of the strip and includes a split upstream
end portion 83 (see FIG. 9) sandwiched over a portion 84 of the
stationary splitter 40 to guide the flying splitter as it moves
back and forth through the cutting station 60.
To swing the bag 21 into its upright position, the arms 76 of the
transfer splitter 73 are supported on a horizontal rock shaft 85
(FIG. 6). The latter is connected through linkage 86 to a follower
87 (FIG. 1b) which engages a cam 89 on the cycle shaft 72.
Accordingly, during the dwell period, the shaft 85 is pivoted first
in a counterclockwise direction (FIG. 6) to swing the blades 75 and
the bag into vertical positions at the end of the conveyor 65 and
then, after the bag is clamped for movement with the conveyor, the
blades are swung clockwise (FIG. 7) back to the pick off station to
receive the next bag.
As the bag 21 reaches its vertical position, the grippers 74 (see
FIGS. 7 and 8) grasp the bag along the opposite edges thereof to
hold the bag for movement with the conveyor 65. Herein, the
grippers are pivotally supported on a yoke 90 (FIG. 7) attached to
one of the links 91 of the conveyor chain 67 and normally are
biased closed by springs 93. As shown in FIG. 8, each gripper
includes a generally V-shaped bellcrank 94, one end of which forms
a jaw 95 which coacts with the yoke to grip the bag. Herein, the
jaws extend through notches 96 in the blades 75 so that only one
panel 42 is clamped between the jaw and the yoke along each edge of
the bag. To open the jaws to receive the bag, a follower 97 on the
other end of the bellcrank 94 is engaged by a cam 99 which, when
advanced toward the follower by an actuating linkage 100 (FIG. 1b),
overcomes the springs to pivot the jaws open to receive the bag. In
the exemplary embodiment, the actuating linkage is moved back and
forth by a face cam 101 mounted on the cycle shaft 72.
After the grippers 74 grasp the bag 21 for movement with the
conveyor 65, the splitter 73 is swung back to the pick off station
61. Thereafter, the conveyor is advanced to cause the lower margin
64 of the bag to ride over a folding bar 103 (FIG. 10) and to be
folded upwardly along the crease 53 and into a substantially
horizontal position as the bag is advanced into a gluing station
104. At the gluing station, applicator nozzles 105 spray hot-melt
adhesive in a strip 106 across the bag and above the crease so the
lower margin can be glued to the side 27 of the bag. As the bag is
moved out of the gluing station, the bar 103 folds the lower margin
upwardly so as to parallel the side of the bag preparatory to
entering a sealing station 107. In the sealing station, jaws 109
and 110 of a pressing mechanism 111 are closed by an actuator 113
(see FIG. 11) and squeeze folded margin against the side of the bag
so the adhesive seals the margin to the side of the bag so as to
complete the formation of the bottom of the bag prior to opening
the latter.
Once the bottom of the bag 21 has been formed, the conveyor 65
advances the bag into an opening station 114 where, during the
dwell period, an opener 115 (FIGS. 12 and 13) is telescoped
downwardly into the bag and is actuated to expand the gussets 33 to
open the bag. Herein, the bag opener includes two plates 116
pivotally mounted on opposite sides of a support 117. Intermediate
their ends, the plates are bent toward each other (see FIG. 13) to
permit easy entry of the plates into the bag as the support is
advanced downwardly from a retracted position above the bag by a
fluid-operated cylinder 119. The support is carried slidably on the
end of a rod 120 projecting downwardly from the cylinder and is
located between upper and lower stops 121 and 123 secured to the
lower end portion of the rod. A spring 124 acting between the upper
stop 121 and the support urges the latter downwardly into
engagement with the lower stop 123. Also connected to the lower end
of the rod are two sets of curved arms 125 (see FIG. 12) whose
lower ends are pivotally fastened to the plates, one set of the
arms being fastened to one of the plates adjacent the bend in that
plate and the other set of arms being fastened in a like manner to
the other plate. Slots 126 (FIG. 13) in the upper ends of the arms
receive a pin 127 which secures the arms to the lower end of the
rod so that, as the rod slides downwardly relative to the support,
the pin slides in the slots and causes the lower ends of the arms
to spread the plates away from each other to expand the side
gussets of the bag (see FIG. 14). The distance which the arms can
pivot away from each other is limited by the support 117 as it
compresses the spring 124 against the upper stop 121.
To limit downward movement of the support 117 so the downwardly
moving rod 120 may overcome the spring 124 and slide downwardly
relative to the support to spread the arms 125, two vertical guide
bars 129 (FIG. 12) on opposite sides of the rod 120 are fixed at
their lower ends to the support 117 and are bushed slidably by a
fixed bracket 130 which also supports the cylinder 119. Threaded on
the upper ends of the bars are stop nuts 131 which, when the
support is pushed downwardly by the rod, engage the upper surface
of the bracket to prevent further downward movement of the support.
At this point, the rod overtravels to spread the arms and plates
116 (see FIG. 14) and thereby to open the bag 21. As the gussets 33
are expanded in this manner, a horizontal kicker plate 134 (FIGS.
1b and 14) strikes the bottom of the bag to help square the bag
before the latter is advanced out of the bag opening station 114.
The plate 134 is carried on the end of a rod 135 adapted to be
reciprocated upwardly and downwardly by a cam 136 on the cycle
shaft 72.
As the open bag 21 is advanced out of the bag opening station 114
by the conveyor 65, a U-shaped holder 137 (FIG. 12) carried on a
chain 139 of another conveyor 140 swings upwardly along each of the
gussets 33 to advance the bag along its predetermined path to be
filled and subsequently closed. The second conveyor is advanced
step-by-step in timed relation with the first conveyor through
suitable mechanism (not shown) and includes one end sprocket 141
(see FIG. 1b) spaced between the sprockets 69 and 70 of the first
conveyor and an opposite end sprocket (not shown). The chain 139 is
trained around the two sprockets of the second conveyor and carries
a bracket 143 (FIG. 12) to which the holder is secured for pivotal
movement between a downwardly opening vertical position and a
horizontally opening position disposed around the bag. The holder
is urged into its normal horizontal position by a spring 144 (FIG.
13) acting between the bracket and the holder but, in the bag
opening station 114, the holder is held downwardly in its vertical
position by a retaining bar 145 (FIG. 12). The latter is positioned
such that, in the bag opening station, the holder is tilted
slightly upwardly along the gussets 33 and, as the bag leaves the
opening station, the holder passes by the end of the bar to swing
upwardly along the bag under the urging of the spring. At this
point, the grippers 74 are still clamping the bag 21 on the first
conveyor 65 and thus retain the bag within the holder 137 as the
two conveyors 65 and 140 advance the bag into the filling station
66. Upon being advanced out of the bag opening station 114, the bag
is slid onto two driven belts 146 which are separated from each
other and which keep the bag from falling downwardly out of the
holder during subsequent advance of the bag. The belts are trained
around a pulley 147 and advanced in timed relation with the second
conveyor to avoid relative sliding between the belts and the bottom
22 of the bag.
In the filling station 66 (FIG. 12), the bag 21 is gripped by a
suction device 149 which pulls outwardly on the front side 27 of
the bag as the grippers 74 captivate the bag in the holder 137.
Then, a charge of product is fed into the bag from a dispenser 150.
To help the product settle within the bag, a kicker platform 151 is
mounted beneath the two belts 146 and is jogged upwardly against
the belts by a cam 153 (FIG. 1b) mounted on the cycle shaft 72.
As the bag 21 is advanced from the filling station 66 by the two
conveyors 65 and 140, the followers 97 on the grippers 74 of the
first conveyor 65 engage a stationary cam 154 (FIG. 12) mounted
above the end sprocket 70 and are opened so the grippers release
the bag. The latter is then carried solely by the second conveyor
140 and the belts 146 and is advanced step-by-step through closing,
sealing and flattening stations 155, 156 and 157 (FIGS. 16, 12 and
15). In the closing station 155, pivoted L-shaped gusset tuckers
159 (FIG. 12) engage the two side gussets 33 between each of the
two panels 42 adjacent the top of the bag and tuck the gussets
toward each other to assure that the bag will close properly. After
the gussets have been tucked inwardly, closing bars 160 are
advanced by a cam 161 (FIG. 1b) to engage the opposite sides 26 and
27 of the bag along the upper margins 163 thereof and crimp the bag
closed. As this is done, a second kicker platform 164 is jogged
upwardly from beneath the two belts 146 by a cam 165 and helps to
settle the product within the bag.
The bag 21 then is advanced from the closing station 155 with the
upper margin 163 being sandwiched between two parallel guide bars
166 (FIGS. 12 and 15) to keep the upper end of the bag from
expanding open as the bag is carried into the sealing station 156
by the second conveyor 140. In the sealing station, two sealing
bars 167 are advanced to seal the top margins of the two side
panels 26 and 27 together to close the bag. As the bars are sealing
the sides together, squaring arms 169 (FIG. 15) adjacent each end
of the top seal being formed are swung toward each other to expand
the upper portion of each gusset 33 while also tucking the
triangular portion 170 at the upper end of each gusset inwardly
beneath the margins to help square the top of the bag. As the arms
reach the ends of their inward swinging, a jogging platform 171
beneath the sealing station is lifted into engagement with the
belts 146 to push the bag upwardly so the top portion of the bag is
pressed against the sealing bars and the arms to square the top of
the bag. Thereafter, the arms, the jogging platform and the sealing
bars are retracted away from the bag and the latter is advanced to
the flattening station 157 to fold the upper margins, now forming a
top seal 163, downwardly onto the top of the bag as is shown in
FIG. 15. The bag subsequently is removed from the machine for
placement into shipping cartons.
From the foregoing, it will be apparent that the machine 20 of the
present invention is adapted to operate in a novel manner so as to
utilize the bag making section 32 in the formation of the
flat-bottom side gusset bags 21. To this end, the bottoms 22 of the
bags are completed by folding the lower margins 64 of the bags
upwardly along the sides 27 of the bags as the latter are advanced
along the fill section 38 of the machine but before the bags are
opened to be filled. By utilizing the novel transfer splitter 73 to
keep the gusset panels 42 separated from each other as the bags are
carried from the pick off station 61 to the conveyor 65, the
grippers 74 may be actuated to clamp the bags for movement with the
conveyor without clamping the gussets closed. Advantageously, this
enables the bottoms of the bags to be completed along the fill
section of the machine while still permitting the bags to be opened
subsequently for filling without need of unclamping the bags from
the conveyor.
* * * * *