U.S. patent application number 10/463292 was filed with the patent office on 2004-12-23 for method and apparatus for making a pre-padded food bag.
This patent application is currently assigned to Cryovac, Inc.. Invention is credited to Boal, Dilip Kumar, Stuckey, James Hal.
Application Number | 20040255556 10/463292 |
Document ID | / |
Family ID | 33418132 |
Filed Date | 2004-12-23 |
United States Patent
Application |
20040255556 |
Kind Code |
A1 |
Boal, Dilip Kumar ; et
al. |
December 23, 2004 |
Method and apparatus for making a pre-padded food bag
Abstract
There is provided a method for manufacturing pre-padded
food-containing bag by perforating across a continuous web of
flattened tubular thermoplastic material, forming an opening in a
layer of the perforated web, separating the layers of the web,
inserting an absorbent the pad through the opening into the inside
of the tubular web and making a seal across the tubular web at
predetermined lengths to form a bag. The result is that a
continuous web of bags containing absorbent pads at discrete
intervals. There is also provided an apparatus for carrying out the
method.
Inventors: |
Boal, Dilip Kumar;
(Greenville, SC) ; Stuckey, James Hal; (Anderson,
SC) |
Correspondence
Address: |
ALSTON & BIRD LLP
BANK OF AMERICA PLAZA
101 SOUTH TRYON STREET, SUITE 4000
CHARLOTTE
NC
28280-4000
US
|
Assignee: |
Cryovac, Inc.
|
Family ID: |
33418132 |
Appl. No.: |
10/463292 |
Filed: |
June 17, 2003 |
Current U.S.
Class: |
53/433 ; 53/459;
53/469; 53/511; 53/567 |
Current CPC
Class: |
B31B 70/81 20170801;
B65B 43/267 20130101; B31B 2155/00 20170801; B65D 75/42 20130101;
B31B 70/946 20170801; B31B 2160/10 20170801; B31B 70/14 20170801;
B31B 70/942 20170801; B31B 2155/003 20170801 |
Class at
Publication: |
053/433 ;
053/459; 053/469; 053/511; 053/567 |
International
Class: |
B65B 031/04; B65B
009/10 |
Claims
That which is claimed:
1. A method of making a bag from a tube of thermoplastic material
comprising the steps of: providing a continuous length of lay-flat
seamless tubular thermoplastic web having an upper layer and a
bottom layer; perforating at least one layer of said tubular web;
forming an opening in said tubular web; separating said tubular web
sufficiently wide for an absorbent pad to be placed through said
opening; placing an absorbent pad into said opening in said tubular
web; removing excess air from the tubular material, and converting
said tubular web into a plurality of end-seal bags whereby a
continuous series of bags containing said absorbent pads at
discrete intervals is formed.
2. The method according to claim 1 wherein said converting
comprises heat sealing across said tubular web to form a bag.
3. The method according to claim 2 wherein said continuous series
of bags containing absorbent pads is wound onto a roll.
4. The method according to claim 1 further comprising adhering said
absorbent pad to an inside surface of said tubular web.
5. The method according to claim 1 further comprising perforating
both layers.
6. The method according to claim 1 further comprising cutting
through said upper layer and perforating said bottom layer.
7. The method according to claim 1 wherein said opening in said
tubular web is formed by an eccentric wheel acting against said
tubular web.
8. The method according to claim 1 wherein the layers of said
lay-flat tubular web are separated by blowing air into said
opening.
9. The method according to claim 1 wherein said excess air is
removed from said tubular web by passing the web through a pair of
nip rolls to squeeze the air out of the tubular web.
10. The method according to claim 1 further comprising slitting
said flat tubular web along one side thereof, inserting said
absorbent pad at an angle to the direction of travel of said web,
and sealing said split side of said web.
11. A method of making a bag from a tube of thermoplastic material
comprising the steps of: providing a continuous length of lay-flat
seamless tubular thermoplastic web having an upper layer and a
bottom layer; perforating at least one layer of said tubular web;
forming an opening in said tubular web; squeezing said upper layer
and said bottom layer together to close off a section of the
tubular web ahead of an absorbent pad; blowing air into said
opening to separate said upper layer from said bottom layer
sufficiently wide for an absorbent pad to be placed through said
opening; placing an absorbent pad into said opening in said tubular
web; removing excess air from the tubular material, sealing said
tubular web into a plurality of end-seal bags whereby a continuous
series of bags containing said absorbent pads at discrete intervals
is formed; and winding said continuous series of bags containing an
absorbent pad onto a roll.
12. A bag machine for forming a bag having an absorbent pad therein
from a roll of flattened tubular web material comprising: a tubular
supply section comprising a holder for said roll of flattened
tubular web material; and a bag forming section comprising; means
for moving said tubular web along a predetermined path; a
perforator for perforating at least on layer of said tubular web; a
means for opening one side of said tubular web; means for inserting
air into said tubular web in an amount sufficient to open said
tubular web enough to insert an absorbent pad; means for delivering
and inserting said absorbent pad into said tubular web; means for
removing air from said tubular web; and a sealer displaced
transversely across said tubular web for delimiting the length
serving to form a bag, said means for delimiting the length forming
a bottom seal of said bag.
13. The bag machine for forming a bag according to claim 12 further
comprising means for winding said bags onto a roll.
14. The bag machine for forming a bag according to claim 12 wherein
said sealer for delimiting said length serving to form said bag is
a heat sealing wire.
15. The padded bag machine for forming a bag according to claim 13
wherein said air removal means is a pair of nip rolls through which
tubular web passes.
16. The bag machine for forming a bag according to claim 12 wherein
said perforator is a perforation knife set to perforate both the
upper layer and the lower layer.
17. The bag machine for forming a bag according to claim 12 wherein
said perforator is set to perforate one of the layers and a knife
is provided to cut a slit in the other layer.
18. The bag machine for forming a bag according to claim 12 wherein
said means for opening said tubular web is an eccentric wheel
acting against said tubular web.
19. The bag machine for forming a bag according to claim 12 wherein
said means for removing excess air from said tubular web is a pair
of nip rolls to squeeze the air out of the tubular web.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a method and apparatus for
making a pre-padded food-containing bag for such products as fresh
poultry and meat. More particularly, this invention relates to
methods and apparatus for placing an absorbent pad into a
food-containing bag made from a web of tubular thermoplastic
material.
[0003] 2. Description of the Prior Art
[0004] Poultry and meat are frequently sold in transparent plastic
bags. Despite the customer being able to see the contents of the
bag prior to purchasing, a problem with this type of packaging is
that the poultry or meat, no matter how carefully prepared,
contains residual blood and other fluids that flow out of the meat
after it has been packaged. The blood and other fluids accumulate
in the package, thereby detracting from its appearance. In
addition, the blood and fluid sometimes leak from the package while
the consumer is transporting it home from the market. To counter
this problem food bag manufacturers include an absorbent pad in the
bag prior to loading the food product. The pad absorbs the exuded
blood and fluid into the pad and also enhances the appearance of
the finished bagged product. The manual labor associated with
placing the absorbent pad in the bag prior to product loading adds
to the cost and time associated with this operation.
[0005] There are numerous patents directed to thermoplastic food
bags with an absorbent pad for packaging food products. One such
patent is U.S. Pat. No. 4,815,590 to Peppiatt, et al. that
discloses a generally rectangular pad attached to the side closest
to the bag opening so that the pad is not dislodged when the
product is placed in the bag. The pad absorbs blood and other
fluids in the meats to keep the package neat and clean and minimize
the, danger of leakage.
[0006] An example of a pad for absorbing exuded juices or liquids
is shown in U.S. Pat. No. 4,410,578 to Miller. This patent
discloses an absorbent pad for use in a bag or tray intended to
contain and display fresh food such as poultry or meat. The
absorbent pad includes a mat of liquid absorbing material, and
liquid impermeable plastic sheets overlying and underlying the
absorbent mat. At least one of the sheets is perforated, and a
spacer is disposed between the two liquid impermeable plastic
sheets to maintain their separation under the compressive load of
the food product resting thereon, such that the ability of the pad
to absorb liquids is unimpaired. When a food product is positioned
upon the upper sheet of the absorbent pad, any exuded liquids will
flow around the pad and enter the pad by capillary action through
the perforated openings in the bottom sheet, and the liquids will
be held out of contact with the food product minimizing
contamination of the product, maintaining its appearance, and
improving its shelf life.
[0007] There remains a need for a pre-padded thermoplastic food
bag. Such a bag would increase packaging rates and reduce labor
cost at the packing plant.
BRIEF SUMMARY OF THE INVENTION
[0008] It is an object of the present invention to provide a method
for making a food-containing bag from a web of thermoplastic
tubular material and placing an absorbent pad therein.
[0009] Another object of the present invention is to provide an
apparatus for making a food-containing bag having an absorbent pad
therein from a web of thermoplastic tubular material.
[0010] Yet another object of the present invention is the provision
of a method for manufacturing pre-padded food-containing bags that
have fewer seals than conventional bags.
[0011] A further object of the present invention is to provide a
pre-padded food-containing bag available in roll form.
[0012] It has been found that the foregoing objects may be
accomplished in accordance with this invention by providing a
method for manufacturing pre-padded food-containing bag by
perforating across a continuous web of flattened tubular
thermoplastic material, forming an opening in a layer of the
perforated web, separating the layers of the web, placing an
absorbent pad through the opening into the inside of the tubular
web and making a seal across the tubular web at predetermined
lengths to form a bag. The result is a continuous web of bags
containing absorbent pads at discrete intervals. There is also
provided an apparatus for carrying out the method.
[0013] More specifically, in a preferred embodiment, a
predetermined continuous length of lay-flat seamless tubular
thermoplastic web is unwound from a roll. The layers of the
lay-flat tubular web are perforated at a predetermined length. The
tubular web is fed through a tube opener where the upper layer
perforations are separated creating an opening. The tubular web
then passes to the inserter where during the seal dwell time, a
pair of nip rollers, located at a predetermined distance from the
web opening, squeeze the upper and bottom layers together. Air is
blown into the opening in an amount sufficient to cause the upper
layer of the tubular web to open sufficiently wide for an absorbent
pad to be inserted through the opening. The absorbent pad may have
either pressure sensitive or low temperature food grade adhesive
attached on one side thereof so that when the excess air is removed
from the tubular web the pad is adhered to one of the layers. The
tubular web, having the absorbent pad positioned between the
layers, passes between laterally adjustable nip rollers to squeeze
the air out of the tubing prior to entering the sealer. As the
tubular web passes through the sealer a transverse seal is made.
The sealer is displaced transversely across the tubular web for
delimiting a predetermined length serving to define the bag size.
The seal may be straight or curved. The seal can be made using an
impulse sealer which employs a hot wire. The bags containing the
pads may be wound into a roll and separated when used at the
perforations in the bottom layer of the tubular web. There is also
provided an apparatus for carrying out the method.
[0014] In a second embodiment, the method is similar to the first
embodiment described above but differs in that when the tubular web
passes through the perforator and opener the bottom layer of the
tubular web is perforated and the upper layer is severed or cut. A
knife is provided on reciprocating base to cut a slit through the
upper layer but not the bottom layer. The perforations in the
bottom layer are provided by perforation knife positioned in
restraining block and piercing only the bottom layer. To insert the
pad it is necessary to open the layers of the tubular web from each
other so that air may be blown into the tube to make the tube wide
enough to insert the pad. There are several means for separating
the layers from each other, such as the eccentric wheel of the
first embodiment or vacuum cups. The pad is inserted and the bag is
form by sealing as in the first embodiment.
[0015] In another embodiment, the flat tubular web is slit along
one side and the absorbent pad is inserted at a right angle to the
direction of travel of the web and the slit side is heat
sealed.
[0016] The packaging costs at the consumer level are reduced due to
reduction in labor costs associated with manual placement of pads
in bag and subsequent increase in productivity by the use of the
pre-padded bags. In addition, there are other applications where it
is desirable to scavenge oxygen from the bagged product, or add
moisture in the bar or anti-microbial pad in the bagged product.
All the above can be accomplished by having a pre-padded bag with
the appropriate pad.
[0017] Other objects, features and advantages of the invention will
become evident from the following description of the drawings and
detailed description of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Having thus described the invention in general terms,
reference will now be made to the accompanying drawings, which are
not necessarily drawn to scale, and wherein:
[0019] FIG. 1 is a front view of a bag-forming machine used to make
pre-padded bags according to an embodiment of the present
invention;
[0020] FIG. 2 is an isometric view of an absorbent pad positioned
in a transparent thermoplastic bag made according to the method of
this invention;
[0021] FIG. 3A-3E show a schematic of the method of forming bags
with adsorbent pads of one of the preferred embodiments of the
present invention;
[0022] FIG. 4 is a top view showing the path of the tubular web
shown in the method of FIGS. 3A-3E;
[0023] FIG. 5 is a top view of the pad inserting section of the
method of the present invention showing inline insertion of the
pads;
[0024] FIG. 6 is a side view of the pad inserting section of the
bag-forming machine;
[0025] FIG. 7 illustrates another embodiment of the pad inserting
section of the present invention showing insertion of absorbent
pads at a right angle to the direction of travel of the web;
[0026] FIG. 8 shows a side view of an alternative embodiment of the
pad inserter taken along line 8-8 of FIG. 7;
[0027] FIG. 9A-9E shows the steps used in the method shown in FIGS.
7-8;
[0028] FIG. 10 illustrates an alternative transverse seal--a curved
seal; and
[0029] FIG. 11 illustrates the pad having an adhesive attached
thereto.
DETAILED DESCRIPTION OF THE INVENTION
[0030] The present inventions now will be described more fully
hereinafter with reference to the accompanying drawings, in which
some, but not all embodiments of the invention are shown. Indeed,
these inventions may be embodied in many different forms and should
not be construed as limited to the embodiments set forth herein;
rather, these embodiments are provided so that this disclosure will
satisfy applicable legal requirements. Like numbers refer to like
elements throughout.
[0031] Referring now to drawings, there is show in FIG. 1 a bag
forming machine for making a pre-padded food-containing bag such as
the one shown in FIG. 2. The bag 10 is made from conventional
tubular thermoplastic packaging material that is defined by seals
30 and has a fluid-absorbing pad 25 placed therein. Typically, the
thermoplastic material will be polyethylene, although other
thermoplastic materials known to those skilled in the art may be
used, such as the materials disclosed in U.S. Pat. No. 3,741,253 to
Brax.
[0032] As shown in FIG. 1, the bag-forming machine 100 includes a
tubular web supply section 120 and a bag forming section 130. The
tubular web supply section 120 includes a pair of cradles 123
mounted on a support base 121 and spaced apart from each other a
sufficient distance to accommodate a roll 12 of tubular plastic
material. The continuous length of lay-flat seamless tubular web 11
may be unwound from the roll 12 and passed around guide roll
124.
[0033] The tubular thermoplastic web 11 is drawn in a flattened
condition from the supply section 120 to the bag forming section
130 through the nips of tensioning rolls 125, 126 and 127, 128 and
around guide roll 129. A pair of drive rolls 131, 132 forming a nip
through which the tubular web 11 passes is provided. The tubular
web 11 passes around idler roll 133 and is guided by guide rollers
134, 135, 136, 137 to the tube perforator and opener 140.
[0034] The tubular web passes through the perforator and opener 140
where the bottom layer of the tubular web is perforated and the
upper layer is severed or cut at a predetermined length. A knife
141 is provided on reciprocating base 142 to cut the upper layer.
The perforations in the bottom layer are provided by perforation
knife (not shown) positioned in restraining block 143 and piercing
only the bottom layer. To insert the pad it is necessary to open
the layers of the tubular web 11 from each other so that air may be
blown into the tube to make the tube wide enough to insert the pad.
There are several means for separating the layers from each other
to create a bag opening, such as an eccentric wheel (FIG. 3) or
vacuum cups (not shown).
[0035] The tubular web 11 then lead to the pad insertion section
150 by passing the tubular web 11 around guide roll 155. During the
seal dwell time, pair of laterally adjustable nip rollers 151, 152
positioned prior to the sealer 160 and located at a predetermined
distance from the opening in tubular web 11 to squeeze the upper
and bottom layers together squeezing the air out of the tubular
web. The nip rollers are positioned from the opening 20 at a
predetermined distance to correspond with the length between the
perforations 17 (FIG. 4). The length of the bag 10 may be varied by
changing the distance between the perforations 17 and changing the
distance from the opening 20 at the pad inserter to the nip
rollers. Blower 153 blows air into the opening formed in the
tubular web causing it to open wide enough to insert an absorbent
pad. At the same time a pad 25 passes from pad inserter 154 through
the opening in the tubular web where the pad comes to rest inside
the tubular web 11. The pad inserter is mounted to vertically
adjustable support 157.
[0036] Sealer 160 is displaced transversely across the tubular web
11 for forming bag 10 at a predetermined a length. The sealer 160
may include a sealing bar 161 which when in sealing position is
disposed against restraining bar 162 opposite each other forms a
transverse seal (straight or curved heat seal) to form the bag. A
hydraulic cylinder 163 is provided for advancing and retracting the
seal bar 161 and restraining bar 162 toward and away from the
tubular web 11. It will be understood by those skilled in the art
that means other than a hydraulic cylinder, e.g. electric motor,
may be used to advance and retract the seal bar. The continuous
length of perforated, pre-padded bags then passes to winder
assembly 170 where the bags are wound up in a roll 31. When roll 31
is full the continuous length of pre-padded bags is shifted to a
second roll 31' and roll 31 is removed and set up for another
winding operation when roll 31' is full.
[0037] A method for making the pre-padded bags 10 is shown in FIGS.
3A-3E wherein a roll 31 of individual bags 10 each having an
absorbent pad 25 is produced. In FIG. 3A, at station #1, a
predetermined continuous length of lay-flat seamless tubular
thermoplastic web 11 is unwound from roll 12. The lay-flat tubular
web 11 has an upper layer 13 and the bottom layer 14. The tubular
web 11 is fed along a path of travel to a perforator 15 and backing
bar 16 where the upper layer 13 and the bottom layer 14 of tubular
web 11 are perforated at a predetermined length to define the
length of the bag (FIG. 4). The perforations are shown by forming
line 17 in FIG. 4. In the case of the upper layer 13 the
perforation is used to form opening 20 and in the case of the
bottom layer 14 the perforation is used to separate each bag for
the next succeeding bag.
[0038] The perforated tubular web 11 is fed to station #2 shown in
FIG. 3B, through a tube opener where the upper layer 13
perforations are separated creating an opening 20. In the
embodiment shown in FIG. 3B the opening is provided using eccentric
wheel 18 acting against the upper layer 13 of the tubular web and a
back up roller 19 to separate at the perforation in upper layer 13.
In another embodiment, that shown in FIG. 1, the opening is formed
by severing or cutting upper layer 13 and perforating the bottom
layer 14.
[0039] As shown n FIG. 3C, the tubular web 11 next passes to
station #3 for pad insertion from the pad inserter 24 where during
the seal dwell time pair of nip rollers 21, 22 located at a
predetermined distance from the opening 20 to squeeze the upper
layer 13 and bottom layer 14 together to close off a section of the
tubular web 11 ahead of the absorbent pad 25 so that when the air
from air source 23 is blown into the opening 20 the upper layer 13
and the bottom layer 14 of the tubular web 11 are caused to
separate sufficiently for absorbent pad 25 to be placed through the
opening and into the tubular web. At the same time the absorbent
pad 25 is inserted inside the tubular web 11 through the opening
20.
[0040] As shown in the enlarged views of FIGS. 5 and 6 the pad 25
is dispensed from a roll of pads 24, such as DRI-LOC.RTM. absorbent
pads available from Sealed Air Corporation, and inserted inline in
the direction of travel of the tubular web. In FIGS. 5 and 6 only
bottom layer 14 of the tubular web is shown for clarity. Thus,
because upper layer 13 is not shown, opening 20 is not shown. In
the embodiment shown in FIG. 5 an indefinite length of pads is fed
intermittently at a predetermined time interval from a stock roll
24 a cutting device (not shown) severs the pads from each other.
Each pad is then delivered at the predetermined time into the
opening 20 of the tubular web. The blowing air assists in pushing
the pad into the tubular web. As shown in FIG. 11, The absorbent
pad may have either pressure sensitive or low temperature food
grade adhesive on one side thereof so that when the excess air is
removed from the tubular web 11 the pad is adhered to one of the
layers, preferably the bottom layer 14.
[0041] The excess air is removed from the tubular web 11 having the
absorbent pad 25 positioned between the upper layer 13 and the
bottom layer 14. As shown in FIG. 3D, station #4, one method of
removing the excess air is to pass the tubular web 11 between
laterally adjustable nip rollers 26, 27 to squeeze the excess air
from the tubing prior to forming the bag.
[0042] Bags are then formed at station #5 by converting the tubular
web 11 into a continuous series of connected end-seal bags 10, each
containing an absorbent pad as shown in FIG. 3E. The bags may be
formed by sealing the tubular web across its width at discrete
intervals. As the tubular web 11 passes between sealer 28 and
restraining bar 29 a transverse seal 30 is made by heated sealing
member 28. The sealing member 28 is displaced transversely across
the tubular web 11 for delimiting a predetermined length serving to
limit the size bag 10. The sealing member 28 is moved toward the
restraining bar 29 to form a seal 30. The seal 30 may be straight,
as shown in FIG. 2 or curved as shown in FIG. 10. It should be
understood that any well-known method of sealing is used to form
the bags 10. The bags containing the pads may be wound into a roll
31. Alternatively, the bags may be folded along the seal and placed
in a box until used.
[0043] FIGS. 7 and 8 illustrate an embodiment of the absorbent pad
dispensing portion of the apparatus showing delivery from a roll 24
of absorbent pads 25 at an angle, preferably a right angle, to the
direction of travel of the bottom layer 14 of tubular web 11
intermittent of perforations 17. For purposes of illustration, the
upper layer 13 is not shown. In the embodiment of FIG. 7, the flat
tubular web 11 (see FIG. 9A) is slit along one side of the
flattened tubular web 11 at slit line 32 (FIG. 9B). The absorbent
pad 25 is inserted through the slit line 32 at an angle to the
direction of travel of the web 11 as shown in FIG. 9C. The split
side of the tubular web 11 containing the pad 25 is band sealed 33
as shown in FIG. 9D. Transverse straight seal 30 (FIG. 9E) or
curved seal 30 FIG. 10) may be used to complete the pre-padded bag
10.
[0044] Many modifications and other embodiments of the inventions
set forth herein will come to mind to one skilled in the art to
which these inventions pertain having the benefit of the teachings
presented in the foregoing descriptions and the associated
drawings. Therefore, it is to be understood that the inventions are
not to be limited to the specific embodiments disclosed and that
modifications and other embodiments are intended to be included
within the scope of the appended claims. Although specific terms
are employed herein, they are used in a generic and descriptive
sense only and not for purposes of limitation.
* * * * *