Method for making a bag-in-carton

A method is disclosed which makes a bag-in-carton by successively and intermittently advancing cartons, the upper ends of which are opened, and during the advancement successively supplying each of the cartons with a flattened bag, and subsequently blowing up the bag. A bag supplying apparatus and a bag blowing up apparatus used for performing the method are also disclosed. The bag supplying apparatus comprises means for supplying tubular material, roller means for intermittently advancing the material, means for providing the material with side folds while the material is being advanced, means for heat sealing the side folded material thereacross at the places spaced by the distance equal to the desired length of the bag to form bottom seams, and means for cutting the material just below the bottom seams to provide bags. The bag blowing up apparatus comprises vacuum horns for forcibly opening the unsealed end of a bag and lid means for blowing up the bag after it contacts the opened end for air sealing thereof.

BACKGROUND OF THE INVENTION 
This invention relates to a method and apparatus for automatically making a 
so-called "bag-in-carton" which is a container having a bag therein. 
A bag-in-carton, which is a combination of a paperboard carton and a bag 
made of plastic, metal foil or the like, has been used as a container for 
products which need air tight packing or for some kinds of liquid. 
A typical method for making such bag-in-carton comprises cutting a tube of 
bag material to provide a length of the tube, sealing one end of the 
length of the tube to form a bag, folding a flat carton blank which is 
punched out from a sheet of paper board so as to enclose the bag therein 
and forming a rectangular paper tube and adhering the bag to the carton 
blank. During the above folding step, upper and lower end flaps of the 
blank are not folded. The obtained rectangular tubes are collapsed and 
then stored flat. When the flattened carton tubes are used, the tubes are 
set up into a rectangular form and the bags therein which are bonded to 
the carton tubes are concomitantly opened. Then, the flaps of the end of 
each of the carton tubes adjacent the sealed end of the bag therein are 
folded and bonded to each other to close the end, and then the carton with 
one end closed is fed to a product loading machine. 
According to such a method, the rectangular carton tubes are stored flat 
for a long time. Thus, if the material of the bags in the carton tubes is 
apt to cause blocking or sticking, the carton tubes are not easily set up 
when they are going to be used. Furthermore, at least a portion of the bag 
is fixed to the carton. Therefore, forces applied from outside of the 
product loaded carton, for example during transportation thereof, tend to 
be directly transmitted to the interior of the bag thereby causing a 
problem of damage to the products in the bag. Furthermore, when the 
process for combining the carton and the bag is effected automatically, it 
is necessary to accurately synchronize the feeding of the carton blanks 
with that of the bags and to make constant the orientations of the cartons 
and the bags. For so dealing with bags, it is necessary that the bags have 
certain stiffness. 
Another typical method comprises putting a sheet of bag material around a 
mandrel, heat sealing the side seam and the bottom portion of the bag 
material to form a bag, and putting a carton blank around the bag and 
bonding the bag and carton at certain places or throughout. In this 
method, too, problems arise unless the bag material has certain stiffness; 
for example, the bag material curls or does not conform to the mandrel. 
Furthermore, this method is also accompanied with the problem of damage to 
the packed products during transportation as in the first method, since 
bonding between the bag and carton is necessary. 
Mechanisms and the process used in the abovementioned two methods for 
bonding bags to cartons are complicated and time consuming. Thus, they 
significantly increase the cost of completed packages. 
Another typical method comprises separately preparing a bag and a carton, 
putting products in the bag and thereafter inserting the loaded bag in the 
carton. According to this method, the possibility of damage to the 
products during transportation decreases since the bag is not fixed to the 
carton. It has been experimentally proven there is less damage to the 
products when the bag is not fixed to a carton than when the bag is fixed 
to the carton. Thus, the bag-in-carton made by the third mentioned method 
is suitable for containing snacks such as biscuits and potato chips. 
However, the loaded bag is not evenly shaped. Usually, the lower portion 
of the loaded bag tends to become larger than the upper portion. Thus, if 
the loaded bag is to be inserted in a carton having a size closely 
corresponding to that of the bag, it is necessary to manually reform the 
loaded bag to an appropriate shape. Or, if the loaded bag is to be 
inserted automatically in a carton, it is necessary that the carton be 
much larger than the bag thereby increasing the cost and provoking 
complaints from consumers. 
SUMMARY OF THE INVENTION 
One object of this invention is, therefore, to provide a method for 
automatically making a novel bag-in-carton which can eliminate the 
aforementioned problems. For eliminating the problems, in this method, 
cartons are previously prepared separately from bags and the upper end of 
the carton is left open; then the bags are automatically fed into the 
cartons; and thereafter bags are automatically opened for readily 
receiving products to be packed therein. 
Another object of the invention is to provide a bag supplying apparatus and 
a bag blowing up apparatus for enabling achievement of the method of this 
invention. 
Other objects and features of the invention will be understood from the 
embodiment explained below referring to the accompanying drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
FIG. 1 schematically shows an automatic packing system for achieving the 
method of this invention, in which many structural parts are omitted for 
convenience of illustration. A bundle 22 of flattened partially formed 
paper cartons 20, which are previously prepared by folding carton blanks 
into a rectangular tubular configuration and adhering side flaps, is 
disposed on a carton rack 24. A carton conveyor 26 (FIG. 2) is disposed 
perpendicularly to the carton rack 24. The conveyor 26 may be of a well 
known closed loop type construction comprising carton holders 28 fixed to 
a chain 30 at appropriate intervals along the chain. The conveyor 26 is 
intermittently advanced in the direction indicated by the arrow so that 
respective holders 28 are successively aligned with the carton rack. When 
a holder 28 stops in alignment with the rack, a vacuum pickup head 32 is 
pushed toward the bundle of the partially formed cartons to the position 
indicated by the broken line in FIG. 2 and then, after it picks up one of 
the partially formed cartons, returns to its original position (indicated 
by the solid line in FIG. 2). During this movement of the pick up head, 
one of the partially formed cartons 20 is received in the holder 28, and 
it is automatically set up by the movement thereof into the holder. Then 
the next indexing movement of the conveyor is effected. The operations 
above are repeated so that the partially formed cartons are successively 
fed along the conveyor 26. For convenience of illustration, only the 
holder 28 at the position adjacent the rack 24 is shown in FIG. 1. 
However, it should be understood that each of the respective cartons 20 in 
FIG. 1 is supported by a holder. 
During the movement of each of the cartons 20 from the position 1 to 
position 4, bottom flaps thereof are folded and bonded. These operations 
may be made by adhesive supply means and any of suitable folding rails 
fixed to a frame (both not shown) which are well known to those skilled in 
this technical field. During this movement of the carton, the forward and 
backward upper flaps are arrested in opened or horizontal position by 
similar folding rails (not shown). The partially formed cartons may be 
supported after an appropriate position by a support rail 34 and guide 
rails 36 so that the holders 28 only work to shift the cartons. Although 
in the illustrated embodiment a structure similar to the guide rails 36 is 
provided before the cartons, it is not shown in the drawing for 
convenience of illustration. A carton detector 37 may be provided at an 
appropriate place so as to stop the entire automatic packing system upon 
detecting absence of a carton. Such detector may be of any well known 
construction such as one using a photocell. 
In the illustrated embodiment, a bag supplying apparatus 38 is associated 
at position 5 with the conveyor. The apparatus 38, although details of the 
construction thereof will be explained later, includes nip roller means 42 
for intermittently advancing a flattened continuous tube 40 of bag 
material, heat sealing means 44 and a cutter 46 for severing the tube 40 
at a place just below the heat sealed portions to form individual bags 48. 
The carton 20 supplied with the bag 48 at the position at which the bag 
supplying means is provided is then transferred to the position 6 where 
the unsealed end of the bag is first opened and then blown up by a bag 
blowing up apparatus 50 the details of which will be explained later. The 
assembly of the bag and the carton in the position 6 is now a 
bag-in-carton which is ready for receiving products to be packed. The 
assembly is then supplied with the products by a loading apparatus 52 
situated at the loading position 9. The loaded assembly is then further 
transferred while partial sealing of the upper opening of the bag (at the 
position of 12), air evacuation from the interior of the bag through a air 
passage 58 left unsealed during the partial sealing (at 13) and complete 
sealing (at 14) are affected. Then the upper flaps of the carton are 
closed to complete the packing process. The mechanisms for partial and 
complete sealing of the bag and for the air evacuation used for the 
purpose just above are conventional in the technical field for packing 
products in bags. So, they are not shown in the drawings. 
Referring to FIG. 3, there is shown the bag supplying apparatus in more 
detail in which reference 60 designates a supply roll of a sheet 40 of the 
bag material. Typical materials for the sheet 40 are a multilayer sheet 
comprising a base sheet of appropriate material such as metal foil and 
various kinds of plastics chosen according to application and 
thermoplastic resinous film applied on the base sheet; such thermoplastic 
film may be of polypropylene, polyethylene, vinyl acetate, vinyl chloride, 
vinyl acetate co-polymer or the like. However, it should be understood 
that the sheet 40 is not limited to "multilayer" form and the 
abovementioned materials; any sheet having heat sealable characteristic 
can be used. Since the sheet 40 is intermittently advanced by the roller 
means 42, a dancer roller 64 is provided for damping tension in the sheet. 
The dancer roller is mounted on an arm 66 which is pivotally connected to 
a frame 62 at a place designated by 68 and biased clockwise as viewed in 
the drawing. Thus, as the tension in the sheet increases, the dancer 
roller goes up to relieve the tension. After passing around guide rollers 
70 and 72, the sheet 40 is wound on a forming post 74 and then side flaps 
or the side marginal portions 78 are heat sealed to each other so as to 
form a tube by heat sealing means 76. For arresting the sheet while it is 
wound on the post and making it closely conform to the same, an 
appropriate guide plate (not shown), for example, one encompassing the 
post with a clearance corresponding to the thickness of the sheet 
therebetween, may be employed. 
Then, the tubular sheet passes between gusset forming discs 77 to form side 
gussets which is one form of side folds and is thereafter flattened 
without dissolving the gussets. At a place upstream of the upper rollers 
of the feed roller means 42 along the sheet, there is provided bottom heat 
sealing means 44. The feed roller means intermittently advances the sheet 
by the distance corresponding to the length of the bag each time and the 
heat sealing means 44 heat seals across the width of the sheet for forming 
a bottom seam while the sheet is stopped. While the transverse heat 
sealing is being effected, the sheet is severed at a place just below the 
preceding transversely sealed portion by the cutter means 46, and 
thereupon, the separated sheet portion (now an individual bag) is fed into 
the carton by the lower rollers of the roller means 42. 
When marginal originally having a tubular configuration such as an inflated 
tube is used, the mechanism (74 and 76) for forming the tube can be 
omitted. Even in that case, however, it is necessary to form side folds 
since the width of the simply flattened tube is greater than the width of 
the carton 20. In this connection, it is easy to form the gusset in the 
structure shown in FIG. 3 since the tube takes an expanded form. However, 
when the material originally having a tubular form is used, it is 
convenient, as shown in FIG. 5, to arrest the tube 40 by pinch roller 
means 73 and another pinch roller means 75 and to provide guide plates 79 
between the pinch roller means 73 and 75 so that as the tube passes along 
the guide plates 79 it is forced to conform to the guide plates. Typical 
materials of such tube are polyethylene inflation film and co-extruded 
composite tubular materials made of, for example, polypropylene and 
polyethylene; nylon and polyethylene; and polyvinylidene chloride and 
polyethylene. However, this invention is not limited to these materials; 
any multilayer tube the inner layer of which is heat sealable or any 
single layer tube having heat sealable characteristic may be used. In 
either case, whether a tube made out of a sheet or material originally 
having a tubular form is used, the sides of the tube may be turned as 
shown in FIG. 6 as another form of the side folds by appropriate guide 
means (guide plates 78 in the illustrated example). In FIG. 6, opposite 
walls of the tube 40 are exaggeratedly spaced for convenience of 
illustration. 
The bag blowing up apparatus 50 will be explained below in more detail. 
As is shown in FIG. 7A, the bag blowing up apparatus comprises vacuum horns 
80 and lid means 82 having air supplying means. The vacuum horns have 
vacuum ducts 81 connected to a vacuum source (not shown) and the lid means 
has an air duct 85 connected to a pressurized air source (not shown). When 
a carton 20 having a flat bag 48 therein reaches the position 6, the 
vacuum horns 80 are actuated so as to contact the bag (FIG. 7B). Then, the 
vacuum is applied through the ducts in the vacuum horns so that the horns 
suck the bag. Then, the upper end of the bag is opened by the movement of 
the vacuum horns to the original position (FIG. 7C). At the same time, the 
lid means 82 is lowered to the position for covering the opened end of the 
bag. Then, air is supplied to the bag 48 through a flexible pipe 84 (FIG. 
8) connected to the duct 85 of the lid means 82 to blow up the bag to the 
extent that the bag generally conforms to the inner walls of the carton 
20. Mechanisms for moving the vacuum horns laterally and the lid means 
vertically while maintaining the communication with the vacuum source and 
the pressurized air source, respectively, are well known to those skilled 
in the art. Thu, they are not shown in the drawings. 
If a carton 50 having therein a bag 48 which is not fully blown up is moved 
to the position 9 and the products are charged into the bag, the expensive 
products are wasted. In this invention, to prevent this problem, means for 
detecting whether the bag is fully blown up or not is provided. Such 
detecting means may comprise a flapper 86 which is biased by a spring (not 
shown) toward the position covering a vent opening 88 in a baffle plate 83 
of the lid means. The strength of the spring is so selected that the 
flapper swings about the pivoting point 87 against the biasing effect when 
the pressure in the bag reaches a predetermined value after the bag is 
blown up and is further supplied with air through the flexible pipe 84 
communicated with the pressurized air source. A switch 92 is also mounted 
on the baffle plate 83 and is adapted to be actuated by the swing of the 
flapper 86. Such actuation of the switch may be performed by a blade 90 
fixed to the flapper. The switch may be associated with a control circuit 
which stops supplying the product to the corresponding bag when the switch 
is not actuated at the time when it should be actuated unless there is any 
trouble. Alternatively, the switch may be so arranged that it stops the 
operation of the whole packing system. The detecting means also can inform 
of the presence of trouble when there is no bag in the sensed carton, 
since the flapper 86 does not swing up also in that case. Therefore, a 
separate detector for sensing the presence of the bag in the carton does 
not need to be provided. After completion of the bag blowing up operation, 
the vacuum horns 80 and the lid means 82 return to their respective 
original positions (FIG. 7A). 
The abovementioned movement of the pick up head 32 and the operations of 
the movable elements of the bag supplying apparatus 38, the bag blowing up 
apparatus 50, the loading apparatus 52 and other mechanisms can be 
obtained from a power source of the conveyor 26 through cams, links, 
chains or the like while maintaining an appropriate timing relative to the 
operation of the conveyor 26. Some solenoids may be employed, if 
necessary, and the actuation thereof may be controlled in an appropriate 
timing relative to the operation of the conveyor. Such means for 
transmitting force and for controlling the operations are conventional in 
this technical field. 
As is explained above, in this invention the bags are made out of a 
continuous sheet or tube separately from the cartons and are inserted in 
the cartons just before the loading of the products. Therefore, the 
material of the bags does not need to have certain stiffness to be 
handled. Furthermore, since the bags are forcibly opened by the vacuum 
horns and the lid means, the tendency of the material of the bags for 
blocking or sticking does not cause substantial troubles. Therefore any 
kind of material may be used for the sheet from which the bags are made. 
Furthermore, in this invention, a process for bonding the bags to the 
cartons, which needs a complicated mechanism, is unnecessary. Moreover, 
the carton used for a bag of a given size can be made smaller than that of 
a carton used in the conventional method for automatically assembling 
separately prepared carton and bag, thereby enabling reduction of cost.