U.S. patent application number 09/939336 was filed with the patent office on 2002-05-02 for tubular bag with ventilation bands and method of making.
Invention is credited to Wang, Ching-Lin.
Application Number | 20020050300 09/939336 |
Document ID | / |
Family ID | 26922258 |
Filed Date | 2002-05-02 |
United States Patent
Application |
20020050300 |
Kind Code |
A1 |
Wang, Ching-Lin |
May 2, 2002 |
TUBULAR BAG WITH VENTILATION BANDS AND METHOD OF MAKING
Abstract
A specialty bag is formed from a circular loom adapted with a
unique mechanism of the current invention such that the resulting
woven tubular sheet contains at least one venting band extending
along the length of the tubular sheet. The tubular sheet is then
cut into individual bag segments. The individual bag segments are
sewn together along their bottom edge to form the final bag having
at least one venting band for the proper venting of the enclosed
items.
Inventors: |
Wang, Ching-Lin; (Oakland,
CA) |
Correspondence
Address: |
Mr. C. P. Chang
Pacific Law Group LLP
Suite 290
Two North Second Street
San Jose
CA
95113
US
|
Family ID: |
26922258 |
Appl. No.: |
09/939336 |
Filed: |
August 24, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60228318 |
Aug 25, 2000 |
|
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Current U.S.
Class: |
139/388 |
Current CPC
Class: |
D03D 3/02 20130101 |
Class at
Publication: |
139/388 |
International
Class: |
D03D 003/02 |
Claims
I claim:
1. A specialty tubular bag comprises a tubular wall woven with a
set of interlocked warp strands and weft strands and at least one
venting band area extending along a length of said tubular bag for
the storage of any items requiring venting wherein said venting
band area comprises only said weft strands providing said function
of venting.
2. A method of manufacturing a specialty tubular bag wherein the
tubular bag wall has at least one venting band extending along a
length of a corresponding tubular sheet, said method comprising the
steps of: weaving a tubular sheet of flexible material with a
circular loom to form an elongated tube comprising woven warp and
weft strands, with said tubular sheet having a longitudinal axis
parallel to said warp strands and a transverse axis parallel to
said weft strands; adapting, during said weaving step with said
circular loom, at least one expansion block disposed with an
associated means of fixturing said expansion block around a
periphery of a concentration ring of said circular loom whereby
said expansion block is used to replace a corresponding group of
otherwise normally supplied warp strands to be woven; creating,
along the periphery of the woven tubular sheet, a set of said
venting bands each corresponding to the location of an expansion
block, where each venting band runs parallel to said longitudinal
axis, said weft strands and said warp strands surrounding the said
expansion block; sectioning off said tubular sheet along a set of
lines perpendicular to said longitudinal axis and with a
predetermined spacing to form a set of tubular segments, whereby
each said tubular segments comprising said set of venting bands
extending longitudinally from a first open end to a second open end
with the first open end of said tubular sheet named the top opening
and the second open end of said tubular sheet named the bottom
opening; and sewing said bottom opening of said tubular sheet
closed along a direction perpendicular to the said longitudinal
axis with said top opening of said tubular sheet left open forming
a desired bag opening.
3. The method according to claim 2 further comprises the step of
adjusting, a width of the woven width from the replaced group of
missing warp strands with the selection of a number of said missing
warp strands such that a width of the resulting venting band is
adjusted accordingly along a transverse direction.
4. The method according to claim 3 wherein the number and
peripheral location of the said groups of missing warp strands are
selected as part of the setup of the circular loom to produce the
corresponding number and peripheral location of said venting
bands.
5. The method according to claim 2 further comprises the step of
selecting a width of said expansion block along the transverse
direction to be wider than the woven width from the replaced group
of missing warp strands such that a controlled amount of lateral
expansion force is exerted by said expansion block onto the warp
strands surrounding said venting band, causing a closer packing of
the woven warp strands along both edges of said venting band than
elsewhere on the woven web, thus insuring the consistency and
cosmetic appearance of the resulting venting band.
6. The method according to claim 5 further comprises the step of
adjusting a height of the said expansion block along the
longitudinal direction such that, during the weaving operation,
said lateral expansion force exerted by said expansion block onto
the warp strands surrounding said venting band can be adjusted
accordingly to cause an adjustable degree of closer packing of the
woven warp strands along both edges of said venting band than
elsewhere on the woven web.
7. The method according to claim 6 further comprises the step of
adjusting the elevation of said expansion block above a
concentration ring of said circular loom such that said lateral
expansion force exerted by said expansion block onto the warp
strands surrounding said venting band can be adjusted accordingly
to cause an adjustable degree of closer packing of the woven warp
strands along both edges of said venting band than elsewhere on the
woven web.
Description
REFERENCE TO RELATED APPLICATION
[0001] This application is a formal application based on
provisional application filed on Aug. 25, 2000, Ser. No.,
60/228,318.
TECHNICAL FIELD OF THE INVENTION
[0002] This invention concerns a specialty bag construction and
method of manufacturing the same. In particular, the bag wall has a
number of venting bands for the proper venting of certain stored
perishable items.
BACKGROUND OF THE INVENTION
[0003] Bulk bags are commonly used to store and transport many
agricultural products. Many such products, especially those easily
perishable ones, require the bag to be properly vented to prevent
the build up of excessive moisture with ensuing growth of mold and
deterioration of the content. Furthermore, these bags are usually
non-reusable due to sanitation concern. Thus, these ventable bags
need to be produced in high volume, having a specifiable degree of
venting yet with very low cost. One common way to achieve this is
to weave in a set of venting bands of specified width and density
with a flat loom. However, the associated post operation involves,
after cutting the panel to size, folding and sewing of two lines to
form the bag. Additionally, the flat loom machine is quite an
expensive investment. Thus, the overall production cost of the bag
can be undesirably high.
SUMMARY OF THE INVENTION
[0004] The present invention consists of a method which
inexpensively and efficiently manufactures such ventable bags in
high volume with a specifiable range of design of venting bands.
Thus, the bag itself is also encompassed by the present
invention.
[0005] The bag is a traditional one having a cylindrical body panel
with one end of the panel sown closed to form the storage cavity.
The other end of the cylindrical body panel is left open for
communication with the interior of the bag. However, the
cylindrical body panel of the bag comprises a specified number and
location of venting bands along the direction of the cylindrical
axis. Furthermore, the width of the said venting bands is also
specifiable by design.
[0006] The method of manufacturing the bag starts with the tubular
weaving of yarns of proper materials with a circular loom whereby
an elongated tubular structure is formed with woven warp and weft
strands. The direction of the warp strands is parallel to the
tubular axis whereas the direction of the weft strands is
perpendicular to the tubular axis.
[0007] However, around the periphery of a concentration ring of
said circular loom a number of mechanical expansion blocks are
disposed at the proper location replacing the otherwise warp
strands to be fed thus woven into said cylindrical body panel of
the bag. For convenience, these locations are to be called band
locations. As there is an absence of warp strands at each such band
location, the resulting woven wall structure of the said band
consists of only weft strands. Without the interlocking power from
the missing warp strands, the flexing weft strands within said band
create substantially larger air gaps in between than otherwise
possible with the presence of interlocking warp strands. These air
gaps within said bands thus form the desired venting structure for
the bag. Therefore, emerging from said circular loom with the
adaptation of the invention embodiment is a woven tubular structure
wherein a number of venting bands parallel to the tubular axis are
built in wherever said invention embodiment is disposed along the
circumferential periphery of the tube. It is also important to
remark that, as part of the function of the circular loom, said
emerging woven tubular structure is actually flattened into a
continuous belt form and wound into a roll for easiness of
subsequent handling.
[0008] The tubular structure is sectioned off along a set of lines
with predetermined spacing to form a set of tubular segments, each
tubular segment having the desired set of venting bands extending
axially from a first open end to a second open end. For
convenience, the first open end of the said tubular structure is to
be called the top opening and the second open end of the said
tubular structure is to be called the bottom opening.
[0009] The bottom opening of the said tubular structure is now sewn
closed along the direction perpendicular to the tubular axis. The
top opening of the said tubular structure is left open forming the
desired bag opening.
[0010] Thus, a storage bag having a cylindrical body panel is
described wherein a desired set of venting bands extending axially
is built in on the body panel. Additionally, an inexpensive and
efficient method is described herein for the manufacturing of such
ventable bags in high volume. Furthermore, said method of
manufacturing embodies the adaptation of a set of simple mechanical
elements onto an existing circular loom.
[0011] Other features, objects and advantages of the present
invention will become apparent with reference to the following
drawings and associated descriptions.
BRIEF DESCRIPTION OF DRAWINGS
[0012] FIG. 1 is a perspective view of a portion of the weaving
mechanism inside a circular loom wherein one mechanical expansion
block of the present invention is disposed to replace an otherwise
corresponding group of warp yarns feeding the weaving
mechanism;
[0013] FIG. 2 illustrates a section of a woven tubular structure
coming out of an unmodified circular loom wherein the woven warp
and weft strands are partially shown to illustrate their
orientation;
[0014] FIG. 3 illustrates a section of a woven tubular structure
coming out of a circular loom modified with the present invention
wherein a set of six venting bands made with the present invention
is also illustrated;
[0015] FIG. 4 is a perspective illustration of a small section of
the detailed woven structure including the corresponding section of
a venting band made with the present invention;
[0016] FIG. 5 illustrates a prior art finished bag made from a
section of a woven tubular structure coming out of an unmodified
circular loom, after the bottom opening of the sectioned tubular
structure is sewn closed; and
[0017] FIG. 6 illustrates a finished bag made from a section of a
woven tubular structure coming out of a circular loom modified with
the present invention, after the bottom opening of the sectioned
tubular structure is sewn closed.
DETAILED DESCRIPTION OF THE INVENTION
[0018] FIG. 5 illustrates a typical prior art bulk bag made with a
circular loom. The cylindrical body panel 10 comprises many tightly
interlocking strands of woven warp 2A and woven weft 3A woven by a
well-known circular loom machine. The material for the warp and
weft strands can be any of the many materials compatible with the
circular loom. Some examples are polyethylene, polypropylene and
nylon. It is important to remark that, as part of the function of
the circular loom, the said emerging woven cylindrical body panel
10 is actually flattened into a continuous belt form and wound into
a roll for easiness of subsequent handling. The bottom opening of
the cylindrical body panel 10 is sewn closed to form a sewn bottom
edge 12. The top opening 11 comes naturally out of the sectioning
operation of the tubular body structure into bag segments.
[0019] Although many such bulk bags are commonly used to store and
transport a wide variety of products and materials, many such
products, especially those easily perishable ones, require the bag
to be adequately vented to the ambient to prevent the build up of
excessive moisture with ensuing growth of mold and deterioration of
the content. Some examples are potatoes and vegetables. For such
products, the tightly interlocking strands of woven warp 2A and
woven weft 3A of the prior art bulk bag does not allow adequate
degree of venting to the ambient and means of controllably
increasing the degree of venting must be devised to solve the
problem.
[0020] FIG. 6 illustrates a bulk bag from the present invention
whereby the desired degree of increase of venting is accomplished.
As stated above, the cylindrical body panel 10 comprises many
tightly interlocking strands of woven warp 2A and woven weft 3A.
The bottom opening of the cylindrical body panel 10 is sewn closed
to form a sewn bottom edge 12. The top opening 11 comes out of the
sectioning operation of the tubular body structure into bag
segments. However, around the periphery of the cylindrical body
panel 10 a set of venting bands 9 is disposed. Within each venting
band 9, instead of having both warp and weft strands, only woven
weft in venting band 3B exists. Without the interlocking power from
the missing woven warp 2A, the flexing woven wefts in venting band
3B within the said venting band 9 now create substantially larger
air gaps in between than otherwise possible with the presence of
interlocking woven warp 2A. These air gaps within said venting band
9 thus form the desired venting structure for the bag of the
present invention. The method by which these venting bands 9 on the
cylindrical body panel 10 are manufactured is described below.
[0021] The method of manufacturing the bag starts with the tubular
weaving of yarns of warp and weft materials with a well-known
circular loom whereby an elongated tubular structure is formed with
woven warp and weft strands. FIG. 1 is a perspective view of a
portion of the weaving mechanism inside a circular loom wherein a
full circle of radially converging warp strands 2 are
interlockingly woven with another set of circumferentially directed
weft strands 3. For easiness of viewing, neither the full set of
warp and weft strands nor the circular-weaving heads are shown.
After passing through the underside of a concentration ring 1, the
just woven cylindrical web turns vertical in direction, forming a
cylindrical body panel 10 and continues to be pulled upwards toward
an ultimate take up roller which is not shown here. The direction
of the woven warp 2A is parallel to the tubular axis whereas the
direction of the woven weft 3A is perpendicular to the tubular
axis.
[0022] Around the periphery of the concentration ring 1 of said
circular loom a number of expansion blocks 7 are disposed at the
proper location replacing the otherwise converging warp strands 2
to be fed thus woven into said cylindrical body panel 10 of the
bag. For convenience, these locations are to be called band
locations. For simplicity, only one expansion block 7 is shown. The
expansion block 7, through a cylindrical link 6, is attached to a
flexible belt 4 whose outer end is fixed at a convenient tie point
5 on the frame of the circular loom.
[0023] The absence of woven warp 2A at each such band location
results in the presence of only woven weft 3B in said venting band
9. Without the adaptation of the present invention, as illustrated
in FIG. 2, a totally symmetric cylindrical structure would be
formed wherein the whole cylindrical wall comprises tightly
interwoven warp 2A and woven weft 3A. Whereas with the present
invention, as shown in FIG. 3, a woven tubular structure wherein a
number of venting bands 9 parallel to the tubular axis are produced
wherever the invention embodiment is disposed along the
circumferential periphery of the tube.
[0024] Additionally, with reference to FIG. 1, the width of the
expansion block 7 is intentionally oversized with respect to the
replaced width of the missing warp strands 2. Thus, during the
weaving operation, a controlled amount of lateral squeezing force
is produced which causes a closer packing of the woven warp 2A
along the edge of the venting band 9. This is illustrated in FIG. 4
which shows a perspective view of a small section of the detailed
woven structure including the corresponding section of a venting
band 9 made with the present invention. Along the two edges of the
venting band 9 are formed two squeeze zones 8 wherein both the
woven warps in left squeeze zone, 2A1 and the woven warps in right
squeeze zone 2A2 are packed with a pitch tighter than elsewhere on
the woven web.
[0025] It should be understood that, with the present invention,
the amount of venting for the bulk bag can be flexibly controlled
with the proper combination of the selection of number, location
and size of the expansion block 7. The invention is applicable, in
particularly, to the storage and transportation of potatoes where a
proper degree of venting is needed to prevent the growth of mold
thus causing deterioration of the potato while avoiding excessive
sun exposure which also causes another type of deterioration.
* * * * *