U.S. patent number RE29,208 [Application Number 05/618,164] was granted by the patent office on 1977-05-10 for method and apparatus for manufacturing synthetic resin tubular film having occludent means in the inside surface thereof.
This patent grant is currently assigned to Kabushiki Kaisha Seisan Nihon Sha. Invention is credited to Kakuji Naito.
United States Patent |
RE29,208 |
Naito |
May 10, 1977 |
Method and apparatus for manufacturing synthetic resin tubular film
having occludent means in the inside surface thereof
Abstract
.Iadd.A method and apparatus for manufacturing a tube to be used
for forming plastic reclosable bags including means for extruding a
continuous annular tube of plastic with circumferentially spaced
axially extending interlocking rib and groove profiles on the
surface from a die shaped to form the tube and profiles, means for
delivering tube separating air through the die into the tube
interior, means for delivering a flow of outside cooling air around
the outer surface of the tube to cool the tube at a rate to
maintain the profiles on the surface of the tube and drawing means
positioned for receicing the tube and drawing it from the die and
flattening it. .Iaddend.
Inventors: |
Naito; Kakuji (Tokyo,
JA) |
Assignee: |
Kabushiki Kaisha Seisan Nihon
Sha (Tokyo, JA)
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Family
ID: |
27520293 |
Appl.
No.: |
05/618,164 |
Filed: |
September 30, 1975 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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Reissue of: |
089540 |
Feb 15, 1961 |
03340116 |
Sep 5, 1967 |
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Foreign Application Priority Data
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Apr 11, 1960 [JA] |
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35-21148 |
Apr 11, 1960 [JA] |
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35-21149 |
Jun 3, 1960 [JA] |
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35-26770 |
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Current U.S.
Class: |
156/91; 156/200;
156/244.15; 156/259; 264/569; 425/327; 156/198; 425/326.1; 156/498;
156/251; 425/392; 24/DIG.50 |
Current CPC
Class: |
B29C
48/32 (20190201); B29C 48/10 (20190201); B29C
48/09 (20190201); B29C 48/12 (20190201); Y10T
156/1067 (20150115); B29L 2023/003 (20130101); Y10T
156/1054 (20150115); B29C 48/0018 (20190201); B29C
48/0019 (20190201); Y10T 156/1008 (20150115); Y10T
156/1005 (20150115) |
Current International
Class: |
B29C
47/00 (20060101); B29C 47/20 (20060101); B32B
007/04 () |
Field of
Search: |
;156/92,244,198,200,251,498,259 ;264/95 ;24/21R ;425/327,342 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Whitby; Edward G.
Attorney, Agent or Firm: Hill, Gross, Simpson, Van Santen,
Steadman, Chiara & Simpson
Claims
Having thus set forth the nature of the invention, what is claimed
is:
1. A method of manufacturing a tube to be used for forming
synthetic resin bags provided with occludent means comprising,
(a) a step wherein is molded continuously by passing through a mold
plastic forming a tubular bag body and integrally therewith in the
inside of said bag body in pairs male and female ribs for occludent
use, next,
(b) a step wherein air is delivered into said tubular body and said
body is kept under uniform pressure,
(c) tension is imparted to the tubular film between said mold and
delivery rolls provided as clasping means of said tubular body,
(d) cold air is delivered from a zone surrounding said tubular body
during its travel to cool the film directly from the outside, and
further
(e) a step wherein the male and female ribs are occluded while said
tubular bag body is being pressed flat.
2. The method of forming a continuous plastic tube with
circumferentially spaced axially extending complementary
interlocking profiles formed integrally therewith by extruding the
tube through a die having an annular opening and profiles
projecting therefrom comprising,
(a) delivering a main flow stream of plastic to the annular opening
in the die forming a tube with shaped interlocking profiles of a
critical shape on the surface of the tube,
(b) delivering separate flow streams of plastic to the profiles
with the separate flow streams joining the main flow stream at the
profiles of the die,
(c) and cooling the plastc at a controlled rate to cool the tubing
and the profiles.
3. The method of making a unitary container material which
comprises,
(a) extruding a one piece continuous closed tube having continuous
axially extending .Iadd.male and female interlocking
.Iaddend.closure elements integral therewith formed at
circumferentially spaced locations on the tube surface and shaped
for releasably interlocking with each other with said elements each
projecting from one surface only of the tube,
(b) .Iadd.directing a small amount of air into the tube to maintain
the tube in its tubular shape, .Iaddend.
.[.b.]. .Iadd.(c) directing a flow of outer cooling air annularly
around the outer surface of the tube at a location where the tube
has reached its final size and diameter after being extruded and
after being filled with the air directed into the tube and
.Iaddend.cooling the extruded tube at a rate so that said elements
remain on the surface on which they appear and do not project on
the opposite surface .Iadd.and so that the closure elements are
cooled retaining their shape and size.Iaddend.,
.[.(c).]. .Iadd.(d) .Iaddend.and separating the tube longitudinally
between said elements.
4. The method of making a unitary container material which
comprises,
(a) extruding a one piece continuous closed tube of a heated
plastic,
(b) simultaneously extruding continuously axially extending
.Iadd.male and female .Iaddend.interlocking elements shaped for
cooperative pressure interengagement and for forcible separation
with one having a shaped projection and the other a shaped groove,
said elements spaced apart from each other in both circumferential
directions and being further apart in one direction than the other,
each element projecting from its one surface only of the tube and
being integral with the tube material and extending therealong,
(c) .Iadd.directing a small amount of air into the tube to maintain
the tube in its tubular shape, .Iaddend.
.[.(c).]. .Iadd.(d) .Iaddend.and .Iadd.directing a flow of outer
cooling air annularly around the outer surface of the tube at a
location where the tube has reached its final size and diameter
after being extruded and after being filled with the air directed
into the tube and .Iaddend.cooling the extruded plastic at a rate
so that each of the elements remains on its one surface only and
does not project from the other surface .Iadd.and so that the
closure elements are cooled retaining their shape and size.
.Iaddend.
5. The method of making a unitary container material which
comprises,
(a) extruding a one piece continuous closed tube of a heated
plastic .Iadd.from an extruder head, .Iaddend.
(b) simultaneously extruding a continuous axially extending
.Iadd.male .Iaddend.fastener element shaped for cooperative
pressure interengagement and for forcible separation with another
.Iadd.female .Iaddend.interlocking element with the element being
integral with the tube and projecting from one surface only and
extending therealong,
(c) and .Iadd.directing a flow of outer cooling air annularly
around the outer surface of the tube at a location spaced axially
from the extruder head .Iaddend.cooling the plastic after it is
extruded at a rate so that the element remains on its one surface
only and does not project from the other surface .Iadd.and so that
the closure elements are cooled retaining their shape and size.
.Iaddend.
6. The method of making a container material for use in forming a
plurality of bags which comprises,
(a) extruding a continuous closed annular heated plastic tube
.Iadd.from an extruder head, .Iaddend.
(b) simultaneously extruding a plurality of pairs of continuous
axially extending .Iadd.male and female .Iaddend.interlocking
elements integral with the tube and extending uniformly axially
therealong with each of the interlocking elements projecting from
one surface only of the tube, .[.and.].
.Iadd.(c) cooling the tube at a rate so that the elements remain on
the surface of the tube on which they were initially formed,
.Iaddend.
.[.(c).]. .Iadd.(d) directing a flow of outer cooling air annularly
around the outer surface of the tube at a location spaced axially
from the extruder head .Iaddend.cooling the plastic after it is
extruded at a rate so that the elements .[.remains.]. .Iadd.remain
.Iaddend.on .[.its.]. one surface only and .[.does.]. .Iadd.do
.Iaddend.not project from the outer surface .Iadd.and so that the
closure elements are cooled retaining their shape and size,
.Iaddend.
.[.(d).]. .Iadd.(e) and drawing the tube axially after it has been
extruded..Iaddend.
7. Apparatus for forming a stream of plastic into an annular
continuous tube with circumferentially spaced axially extending
interlocking means formed integrally with the tube comprising,
(a) a die having an annular opening to form a tube with shaped
complementary .Iadd.male and female .Iaddend.interlocking profiles
opening radially therefrom, each of said profiles projecting on its
own one radial surface only of the tube,
(b) means for delivering tube separating air into the tube
interior,
(c) means for delivering a flow of outside cooling air around the
outer surface of the tube .Iadd.at a location spaced axially from
the die, .Iaddend.said air delivery means having a size and
operating to cool the tube at a rate to maintain said profile on
its own one radial side only of the tube .Iadd.and so that the
closure elements are cooled retaining their shape and size,
.Iaddend.
(d) and drawing means positioned for receiving the tube and
flattening and drawing it from the die.
8. Apparatus for forming a stream of plastic into an annular
continuous tube with circumferentially spaced axially extending
interlocking means formed integrally with the tube comprising,
(a) a die having an annular opening with shaped complementary
interlocking profiles opening radially therefrom,
(b) means defining an annular plastic flow channel leading to said
annular die opening,
(c) means delivering plastic to said flow channel,
(d) a separate plastic flow passage carrying a separate stream of
plastic to at least one of said profiles,
(e) means for delivering a flow of outside cooling air annularly
around the outer surface of the tube,
(f) and drawing means positioned for receiving the tube and
flattening it.
9. Apparatus for forming a stream of plastic into an annular
continuous tube with circumferentially spaced axially extending
interlocking means formed integrally with the tube comprising,
(a) a die having an annular opening with shaped complementary
interlocking profiles opening radially therefrom,
(b) means defining an annular plastic flow channel leading to said
annular die opening for carrying a main flow of plastic,
(c) means delivering plastic to said flow channel,
(d) separate plastic flow passages carrying separate streams of
plastic from the main stream to the profiles,
(e) means for delivering a flow of tube separating air into the
tube interior,
(f) means for delivering a flow of outside cooling air to the outer
surface of the tube,
(g) and drawing means positioned for receiving the tube and
flattening it drawing it from the die.
10. Apparatus for forming a stream of plastic into an annular
continuous tube with circumferentially spaced axially extending
interlocking means formed integrally with the tube comprising,
(a) a die having an annular opening with shaped complementary
interlocking profiles opening radially therefrom,
(b) means defining an annular plastic flow channel leading to said
annular die opening for carrying a main flow of plastic,
(c) means delivering plastic to said flow channel,
(d) separate plastic flow passages carrying separate streams of
plastic from the main flow to the profiles,
(e) means for controlling plastic flow rate through said
passages,
(f) means for delivering tube separating air into the tube
interior,
(g) means for delivering a flow of outside cooling air around the
outer surface of the tube,
(h) and means positioned for receiving the tube and flattening
it.
11. Apparatus for forming a stream of plastic into an annular
continuous tube with circumferentially spaced axially extending
interlocking means formed integrally with the tube comprising,
(a) a die having an annular opening with shaped complementary
interlocking profiles opening radially therefrom for extruding the
tube,
(b) means defining an annular plastic flow channel leading to said
annular die opening for carrying a main flow of plastic,
(c) means delivering plastic to said flow channel,
(d) separate plastic flow passages carrying separate streams of
plastic from the main flow to the profiles,
(e) flow regulating projections adjustably movable into the
passages individually controlling the plastic flow rate through
said passages relative to the main stream,
(f) means for delivering a tube inflating flow of air into the tube
interior,
(g) means for delivering a flow of outside cooling air around the
outer surface of the tube,
(h) and drawing means positioned for receiving and flattening the
tube from the die.
12. Apparatus for forming a stream of plastic into an annular
continuous tube with circumferentially spaced axially extending
interlocking means formed integrally with the tube comprising,
(a) a die having an annular opening with shaped complementary
interlocking profiles opening radially therefrom,
(b) means for delivering tube separating air into the tube interior
after it has been extruded from the die,
(c) means for delivering a flow of outside cooling air around the
surface of the tube,
(d) a pair of pinch rolls positioned above the die for receiving
the tube and flattening it,
(e) means positioned after the pinch rolls for forcing the
interlocking means together,
(f) and a floating guiding member within the tube below said
forcing means aligning the profiles of the tube so that they are
pressed together to interlock between said forcing means.
13. Apparatus for forming a stream of plastic into an annular
continuous tube with circumferentially spaced axially extending
interlocking means formed integrally with the tube comprising,
(a) a die having an annular opening with shaped complementary
interlocking profiles opening radially therefrom,
(b) means defining a plastic flow channel leading to said annular
die opening for carrying a main flow of plastic,
(c) separate plastic flow passages carrying separate streams of
plastic to the profiles,
(d) flow regulating means for the passages controlling the plastic
flow rate through the passages relative to said channel,
(e) means for delivering a tube separating flow of air into the
tube interior extruded from the die,
(f) means for delivering a flow of outside cooling air around the
outer surface of the tube,
(g) and drawing means positioned for receiving and flattening the
tube from the die.
Description
This invention relates to a method and apparatus for manufacturing
bags made of synthetic resin, wherein have been formed integral
with the bag material at the inner surface of the bag mouth
vis-a-vis each other, a male rib and a female rib (the female rib
has a groove therein for interlockingly receiving the male rib)
which are provided as to be occlusive with respect to each other.
It comprises a method of automatically manufacturing the aforesaid
bags by employing an apparatus consisting of means provided with a
mold for molding continuously material pressed out by a synthetic
resin extruder into a tube in which a male rib and a female rib
rises in the inside surface thereof in parallel to its axis, means
for air-cooling positively this tubular bag material during its
travel, means for pressing this material into a flat belt-like form
and maintaining the male and female occludent means in a state
wherein proper engagement thereof is maintained and means whereby
the aforesaid material is thereafter successively cut one by one
into bag width units and simultaneously the cut edges thereof are
heat sealed by a heated blade, and by utilizing the speed
difference of the conveyor belt the cut edges of the bags are
separated apart, and the heat sealed edges are pressed to ensure
the airtightness thereof.
An object of this invention is to provide a bag made of synthetic
resin wherein the step of adhering to the bag material the male rib
and female rib that are used to close the bag mouth by occlusion is
obviated, and the appearance of the bags is improved by forming
vis-a-vis said male rib and female rib simultaneously with the
formation of the bag material and integrally therewith at the inner
surface portion of the bag material that is to become the bag
mouth.
Another object of the invention is to provide a method of
manufacturing efficiently a bag made of synthetic resin and
equipped with occludent means by forming continuously a bag
material in tubular form, then during its travel air-cooling it
positively and pressing it into a flat belt-like form, and
thereafter cutting this material with a heated blade successively
into the required width while simultaneously heat sealing the cut
edges.
A still another object of the invention is to provide for bringing
into register accurately the relative positions of the female and
male ribs of the individual bags that are produced so as to enable
their engagement and separation to be smoothly and perfectly
accomplished, this registration being obtained by arranging the
tubular bag material preparatory to the cutting and heat sealing by
the heated blade in such a fashion that the male and female ribs
are maintained in a perfectly occluded state and in this state are
gradually flattened.
A further object of the invention is to provide for an enhancement
of the airtightness of the bag by ensuring the perfect jointing of
that part near the male and female ribs whose perfect adhesion by
means of the sealing action alone at the time of cutting can hardly
be expected; this being achieved by cutting and heat sealing with a
heated blade successively one by one the bag material in bag width
and simultaneously by utilizing the difference in speed of the
conveyor belt to separate apart the cut portions and thereafter
pressing the heat sealed edges of the bags.
A still further object of the invention is to provide an effective
method and apparatus capable of manufacturing efficiently a bag
made of synthetic resin and equipped with occludent means in the
inside surface thereof by carrying out these operations
continuously and automatically.
A still further object is to provide for freely regulating the
strength of the occludent engagement depending on the use to which
the bag is to be put by regulating the amount of resin flowing into
the molding groove for forming the occludent ribs by means of the
provision of freely adjustable resistance projections at a point
below the molding grooves in the extrusion gap.
The bag material is molded into a long continuous tube, which is
obtained by extruding from a conventional extruder a synthetic
resin under heated state upward through an annular extrusion gap to
form continuously a tubular body in which are formed by means of
incision-like molding grooves provided in a section of the annular
extrusion gap simultaneously in the inner surface thereof raised
male and female ribs parallel with the line of generation of the
tubular body. Then, in transporting this while clasped in a state
of flatness by means of a pair of rolls provided at the top of the
apparatus, air is first blown from the aforesaid mold into the
tubular bag body to maintain the same in a swelled state between
the mold and the aforesaid rolls and by concurrently blowing in
cold air uniformly from air inlet pipes surrounding the tubular
body against the tubular body maintained in the swelled state the
film is cooled uniformly. The tubular body is then guided to the
section for engaging the occludent means. However, by inserting and
providing, as to reside constantly in the tubular body by its own
weight or suitable means, a guide device having grooves which
engage respectively the female and male ribs, and by causing the
occludent ribs to fit respectively into their guide grooves as to
align the two ribs in a position suitable for engagement, and
thereafter engaging the two ribs by confining the tubular body from
both sides when it advances through the narrow gap in the section
for engaging the occludent means, followed by passage through a
roll which acts as a pressing as well as a feeding roll, the
tubular bag body is secured together in a perfectly occluded state.
The bag material which is now flat and maintaining its occluded
state can be finished into individual bags by cutting followed by
sealing the cut edges. In actual practice, however, owing to the
necessity of accomplishing printing of such as trademarks,
tradenames, etc. on the bag surface, the bag material that has been
formed in a flat and continuous state, as described hereinabove, is
first wound up on a reel, transferred to the printing step where
after printing it is rewound on the reel and thereafter cut and the
cut edges simultaneously sealed. And the apparatus for achieving
the above-described results comprises an apparatus in which: The
flat belt-like bag material, in which the occludent state is
maintained as described hereinabove, is continuously delivered
through delivery rollers at a predetermined speed. The forward part
of this bag material while being transferred to a conveyor belt
whose rate of travel is greater than the delivery speed of the
delivery rollers is at this point of transfer heat sealed as well
as cut into predetermined widths whereby the bag that has been cut
away from the bag material is separated apart from the cut edge of
the bag material as a result of the difference in the relative
speeds of the delivery rollers and the conveyor belt. This is
followed by finishing each of the individual bags by sealing to
airtightness the cut edges by pressing the cut edges between a
pressure plate and the conveyor belt. However, depending upon the
use to which the bag is to be put, the mold may be constructed in
which, at a point below the molding grooves for molding the
occludent ribs provided in a section of the annular extrusion gap
of the mold, communicating passages which communicate with said
molding grooves are branched off from said extrusion gap, and near
the entrance of the communicating passage resistance projections
are provided in the extrusion gap interior such that their
positions are freely adjustable from the outside of the mold by
means of such as a screw.
The mode of practicing the invention will be described concretely
below with reference to the accompanying drawings, in which:
FIG. 1 is a side elevation showing an apparatus which continuously
molds a bag material, occludes the male and female ribs thereof and
while flattening the same into a flat belt-like shape winds it
up;
FIG. 2 is a detailed front elevation in section of that section
which continuously molds the bag material;
FIG. 3 is a top plan view of a mold section;
FIG. 4 is a cross-sectional view of the bag material taken along
lines X--X of FIG. 2;
FIG. 5 is an explanatory view showing that section for engaging the
occludent means;
FIG. 6 is a front elevation of a guide for aligning the male and
female ribs;
FIG. 7 is a top plan view of the above;
FIG. 8 is a side elevation showing the relationship between the
above guide and that section for engaging the occludent means;
FIG. 9 is a front elevation illustrating the above
relationship;
FIG. 10 is a top plan view in section of that section for engaging
the occludent ribs;
FIG. 11 is a top plan view showing the bag material subsequent to
its having been occluded;
FIG. 12 is a front elevation in vertical section showing a
modification of the mold;
FIG. 13 is a top plan view of the above;
FIG. 14 is a perspective view showing a core of the above mold;
FIG. 15 is a perspective view of a molding plate having uniform
talon-shaped incisions for molding the occludent means, which plate
is attached to the topside of the above core;
FIG. 16 is a detailed side elevation showing a resistance
projection provided in the above mold;
FIG. 17 is an end view of said resistance projection;
FIG. 18 is a front elevation showing an apparatus for forming from
the bag body molded by the abovedescribed apparatus the individual
bags by cutting said bag material to predetermined widths and
simultaneously heat sealing the cut edges thereof;
FIG. 19 is a top plan view showing the conveyor belt section
thereof;
FIG. 20 is an enlarged view in section of the resultant synthetic
resin bag;
FIG. 21 is an enlarged view in section showing a modification of
the occluding ribs;
FIG. 22 is a cross-sectional view showing the bag material in which
two sets of occluding ribs have been formed; and
FIG. 23 is a descriptive drawing showing the above bag material in
its flattened form and the location where it is to be cut.
In FIG. 1, A is the synthetic resin extruder; B, the mold which
serves as the extrusion outlet; C, the cold air discharge section;
D, the engaging section; and E, the windup reel.
While the extruder A is constituted such that the synthetic resin
material is extruded under a heated state, and it is possible to
use one that is of a conventional structure, the extrusion outlet
which serves as the mold B, as shown in FIG. 2, consists of a
combination of an inverted truncated cone-shaped outer mold 1 and a
core 3 such that a narrow annular extrusion opening or gap 2 is
formed therebetween. In the central bottom part of the core 3, an
air inlet tube 4 is provided, while the bottom part of the outer
mold 1 constitutes an introductory cavity 5 which communicates with
the extruder A from which the synthetic resin is extruded and
delivered via said introductory cavity 5 to the aforesaid extrusion
gap 2. As shown in FIG. 3, there are formed molding grooves or
profiles 7 and 8 in the outer surface of the core 3 communicating
with the extrusion gap 2 for forming integrally with the bag body 6
the male and female ribs 9 and 10 for occlusive use.
Directly above this mold B there is provided a pair of delivery or
pinch rolls 11, 11 disposed in lateral fashion facing each other
for clasping and delivering in a flat state the tubular bag body 6
that is extruded from the mold. And the apparatus is constituted
such that, in the meantime, air is blown in small amounts into the
tubular bag body 6 from the bottom through the aforesaid air inlet
tube 4, and with the top part of the bag body 6 being held together
by means of the delivery rolls 11, 11, the bag body 6 is swelled
and maintained in a tubular shape. Below the rolls 11, 11 there is
provided a pair of guide plates 12, 12 facing each other in roof
fashion whereby the shoulder portion of the bag body 6 swelled into
a tubular shape is guided and is gradually pressed flat as shown in
FIG. 2 and passes between the rolls 11, 11. These guide plates 12,
12 are provided respectively with adjusting rods 13, 13 by which
the angle of inclination of these guide plates are controlled.
At that part of the apparatus where the tubular bag body 6 ascends,
a cold air discharge section C is provided. As illustrated in FIG.
2, several tier of air supply pipes 14 are provided annularly
surrounding the periphery of the tubular bag body 6, and the air is
appropriately supplied to the annular pipes 14 from communicating
pipes 15 and issues from numerous orifices 16 provided in the inner
periphery of each of the air supply pipes 14 is blown against the
outer surface of the bag body 6 to remove heat from the freshly
molded film and thus cool the same.
The bag body 6 which leaves the delivery rolls 11, 11, as shown in
FIG. 1, after passing through such as intervening guide rollers 17,
17 and 18 advances upward and is guided to the section for engaging
the occludent ribs 9 and 10 which also may be termed rib and groove
elements. The female rib has a groove therein for releasably
interlockingly receiving the rib element. This section for engaging
the occludent ribs D is constituted as shown in FIGS. 8, 9 and 10,
and in first passing the end of the bag body 6 through this
section, an aligning means or guide 19 is first of all inserted
into the mouth of the tube where it is held therein. As is clear
from FIGS. 5 to 9, the guide 19 is a device which is relatively
flat whose sides are boat-shaped and having guide grooves 21, 22
which extend longitudinally along both sides thereof in the
direction of the advance of the bag body wherein the male and
female ribs fit in respectively from the wide mouth 20 at the
bottom of the guide 19 and travel therealong. If possible, the
device preferably should be of suitable weight so that it will
reside in the bag body 6 while maintaining to a certain extent its
desired position by means of its own weight without hindering
however the advance of said bag body 6. However, on account of the
fact that the guide 19 is disposed in a position between a pair of
engaging plates 24 and a retaining plate 25 mounted to the machine
frame 23, even if its own weight is light, when disposed near the
engaging plates 24, its position may be maintained in general at
its proper place due to its relative position with respect to the
engaging plates 24. Furthermore, if necessary, it is also possible
to control the position of the guide 19 by providing at a position
near its wedge-shaped portion at its top a pair of rollers rotating
in an opposite direction to the direction of advance of the bag
body 6 and in light contact with the outer surface of said bag body
6. Or alternatively, the utilization of magnetism is another
possibility.
While the structure of the guide 19, as illustrated, consists of a
combination having at its one end a plate 26 having guide grooves
21, 22 and at the other end a plate 27 connected by a pair of stud
bolts 28 having screwed at one of their ends nuts 30 in a passage
29 formed in the latter plate 27 to which the stud bolts have been
fitted as to extend therein, and spring 32 are provided on the stud
bolts between the plate 27 and another pair of nuts 31 screwed to
the middle portion of the stud bolts whereby the distance between
the two plates 26 and 27 are regulated so as to adapt the above
distance to conform with the width of the bag body 6, this
regulating mechanism is not necessarily indispensable to the
guide.
The male and female ribs of the bag body 6 are guided to the proper
positions by means of the guide grooves 21, 22 of this guide 19 and
their positions brought in register. And as the bag body 6
advances, by being pressed from both of its sides as it proceeds
through the narrow gap 33 formed between the pair of engaging
plates 24, the male and female ribs 9, 10 are made to engage with
accuracy. These engaging plates 24 are mounted as to be easily
attachable or detachable by means of bolts 35 in long openings 34
in the machine frame 23. On the other hand, the retaining plate 25
has a long groove 36 just sufficient for the free passage of the
flat bag body 6 therethrough, and above said retaining plate a
buoyant bed 37 consisting of such as felt or soft rubber for
absorbing the shocks should the guide 19 make up-and-down
oscillating movements.
Since the bag body 6 which has thus passed through the gap 33 of
the engaging plates 24 are flat with their male and female ribs
being in positive engagement, it is very convenient as their top
and bottom edges can be accurately determined when cut across at
the lines such as I--I, II--II and III--III, as shown in FIG. 11.
It is also suitable when printing is to be applied to its surface
since the misalignment in the print positions will not occur. The
bag body 6 thus molded into a flat belt-like shape may be
immediately transferred to the bag manufacturing steps to be
described hereinafter. In actual practice, however, since in most
cases, printing of such as trademarks, trade names, etc., are
accomplished, it is perhaps convenient to first wind up the bag
material in this state by guiding the same to a windup reel E after
passing over, as appropriate, the guide rollers 38, 38 and 39.
In the hereinabove-described apparatus, the cross-sectional shape
of the male and female ribs suitable for occlusion of the bag body
6 can be obtained by suitably designing the configuration of the
molding grooves 7, 8. The cross-sectional shape of these female and
male ribs 9, 10 may be suitably determined in accordance with the
uses to which the bags are to be put. For example, as shown in FIG.
21, for a container to be used for fine powders the ribs may be so
formed so that the labial section of the female rib 9 is turned
inward along the length of the rib while the male rib 10 is formed
arrow-headed. In addition, regardless of the shapes of the male and
female ribs, when two sets thereof are formed facing each other, as
illustrated in FIG. 22, and subsequently cut along line O--O midway
between the two when the bag body has been flattened as in FIG. 23,
two bags are obtainable at the same time. Needless to say, in this
case the guide 19 to be used for occluding the ribs will be
provided with guide grooves suitable for guiding the two sets of
ribs and simultaneously causing the occlusion thereof.
On account of the fact that the molding grooves 7, 8 branch off
from the annular extrusion gap, the passage therethrough of the
synthetic resin is at times difficult depending upon the
configuration of the grooves. To deal with this difficulty, the
apparatus is provided with a resistance projection, which is
adjustable from the outside, at a point opposite the lower end of
the groove whereby a part of the resin that is extruded is
conducted into the molding grooves. By adjusting the aforesaid
resistance projection, the amount of resin flowing into the molding
grooves is regulated and thus the strength of the occludent ribs,
that is, the strength of occlusion is regulated in accordance with
the uses to which the bag is to be put. In FIGS. 12 to 17 are
illustrated the mold in which has been provided this adjustment
means.
As shown in FIGS. 12 and 13, the outer mold 101 is fitted inside a
holder 103 with a core 102 in turn being fitted inside said outer
mold 101 so as to form between said outer mold and core a narrow
annular extrusion channel or gap 104. The top 104.sub.1 of the
extrusion gap 104 is tubular in shape whereas the bottom 104.sub.2
is so constituted as to taper conically while at the same time the
gap gradually widens. The bottom of the holder 103 has a central
part 105 and a circumferential part 106, which by being connected
together integrally by means of several connecting members 107 form
the shape of a wheel. Hence, though annular openings 108, thus
formed the bottom of the aforesaid extrusion gap 104 communicates
with the synthetic resin feed passage 109. And with the central
part 105 being fitted at its bottom with a guide facing 100 of an
inverted cone shape, the material that is fed from the bottom is
conducted uniformly around to the annular openings 108 to be
introduced into the extrusion gap 104.
The molding grooves for forming the occludent ribs are provided in
a disk-shaped molding plate or die 110 having talon-shaped
incisions 111 and 112 as shown in FIG. 15 and is attached to the
upperside of the aforesaid core 102. Precisely, while the incisions
111, 112, which constitute a set of the molding grooves are incised
in a part of the circumference of the molding plate 110 with the
shape of the uniform talons being of a wide variety, since their
positions will be determined by the size of the mold, by providing
molding plates 110 of the same size having a wide variety of
incisions and selectively using the same, it becomes possible to
form ribs of any desired shape. For this purpose, several screw
holes 113 are tapped in the upperside of the core 102, and in
positions corresponding to said screw holes 113 in the molding
plate are provided attaching holes 114. Thus, by screwing cap
screws 115 into these holes 113, 114 the molding plate 110 is
attached to the upperside of the core 102 as to be readily
detachable.
In the aforesaid core 102, as is shown in FIGS. 12-14, two passages
116, 117 are provided, the bottom end of which passages opening
into the extrusion gap 104 at the side of the core and the upper
end, towards the aforementioned incisions 111, 112. Slightly below
these passages 116, 117 are fitted as to be freely adjustable
inwards or outwards resistance projections 118, 119 having a
cross-sectional face representing an inverted triangle, the tips of
which protrude into the extrusion gap 104. In order to install
these resistance projections 118, 119 in the above manner, first,
guide holes 120 of the same shape as the above projections are
provided in the side wall of the outer mold 102 in which these
projections fit as shown in FIG. 16. By slidably fitting the
projections in these guide holes 120, the rotation of the
projections is prevented, and they are made to move in and out
while maintaining the position as shown in FIG. 17 in which one of
their ridges is at all times facing downwards. To the outer end of
these projections adjusting screws 124, 125 provided with finger
pieces 122, 123 are respectively screwed into screw holes 126 bored
and tapped in the holder 103. Each of the screws 124, 125 are
provided at their tips with a headed push piece 127, which in turn
loosely fits into a cavity 128 wider in its interior provided in
the ends of each of the resistance projections 118, 119. These
resistance projections 118, 119 have been constituted thus, whereby
the necessary inward or outward travel of the respective resistance
projection 118 and 119 are achieved by means of the abutment of the
heads 129 of the headed push pieces 127 against the end of the
resistance projections 118, 119 in the cavities 128 when the
adjusting screws 124, 125 are turned from the outside.
In order to make into a tubular form the bag body molded by
extrusion from the above mold, air is blown in as in the case of
FIG. 1 to effect the immediate swelling of the bag body, and
thereafter cold air is blown against it from the outside. For this
purpose, as means for feeding air into the bag body interior, holes
130, 131 of suitable size are formed in the central parts of the
core 102 and the molding plate having talon-shaped incisions 110,
respectively, and an air inlet 132 bored in the center of the
central part 105 of the aforesaid holder is opened upwards in the
center hole 130 with said air inlet 132 being made to communicate
with an air feed pipe 133 connected to the circumferential part 106
by means of a duct 134 which has been provided as to pass through
one of the radial connecting members 107.
The synthetic resin in a heated state that is fed from an extruder
in to an apparatus as hereinabove described advances to the feed
passage 108 from where it passes through the annular openings 108
and reaches the lower opening of the extrusion gap 104. Then it
gradually spreads around the conical-shaped portion of the bottom
104.sub.2 of the extrusion gap 104 where it gradually becomes
thinner as it rises and finally issues forth in a tubular shape
from the upper end thereof. In the meantime, since air issues
constantly from the air inlet 132, as the tubular body leaves the
extrusion gap 104 the periphery thereof expands uniformly by means
of the internal air pressure as to stretch the film whereupon by
delivery of cold air a bag body as described hereinbefore is
obtained. In this case, the resin that rises in the extrusion gap
104 of the mold upon reaching the resistance projections 118, 119
is separated by the downward facing ridges 121 and rises along the
face of the projections, and at the same time a portion of the
resin is continuously introduced into each of the branching
passages 116, 117 where it gradually rises in these passages and is
extruded through the respective incisions 111, 112. As a result,
needless to say, not only is it possible to form the occludent ribs
in the inside of the bag body integrally therewith, but also since
by regulating the adjusting screws 124, 125 as to cause the
resistance projections 118, 119 to protrude deeper into the
extrusion gap 104, on account of the resistance, the amount of the
resin fed to either the passage 116 or 117 is lessened as compared
with the case when the projections are retracted, it becomes
possible to regulate the amount of resin flowing to the incisions
111, 112 by the adjustment of the position of each of the
resistance projections.
Regardless of which of the hereinbefore-described molds are
employed, the bag body that has been molded as described
hereinbefore is then processed further in the following manner.
First, by using a guide the male and female ribs that have been
formed integrally in the bag body are occluded, then after
flattening, to the surface of the bag body is imparted, if
required, the desired printing and thereafter by using an apparatus
to be described hereinafter the bag body is cut into the individual
bag and simultaneously therewith the cut edges of the bags are heat
sealed. The apparatus for accomplishing the cutting and heat
sealing of the bags is illustrated in FIG. 18 et seq. in which: 201
is the machine frame, 202 are a pair of superposed delivery rollers
disposed at one end of the machine frame, while 203 are a pair of
superposed belts which by means of a pair of rollers 204, 205
disposed longitudinally travel at a rate equal to the peripheral
speed of the rollers 202. The flat belt-shaped bag body 6 that is
to be cut is conducted via a guide roller 206 to between the
superposed delivery rollers 202 while their male and female ribs 9,
10 are being maintained in an occludent state, and then by being
further passed between the superposed belts 203 the delivery of the
bag body is achieved continuously at a constant speed.
In a position forward of this belt 203, rollers 207, 208 are
disposed longitudinally, around which an endless conveyor belt 209
is mounted. The tip of the bag body 6 which is delivered forth, as
described hereinbefore, is made to be transferred smoothly from the
belt 203 to the radially moving part of the conveyor belt 209. The
surface of this conveyor belt 209 by being imparted a layer of such
as, for example, silicon rubber is maintained so that the bag body
does not stick to the surface of the conveyor belt as a result of
operations such as cutting and heat sealing. In addition, by
suitable determination of the rotating speed of the rollers 207,
208, the rate of travel of the conveyor belt 209 is made to be
greater than that of the bag body 6. Underneath the conveyor belt
209 there is provided an elevator rack 211, which is held to the
machine frame 201 by means of guide members 210 as to be capable of
up-and-down movements. And by connecting this elevator rack with
the delivery roller 202 through cooperatively coupled fore-and-aft
rollers 214 mounted on their respective crank plates 213 provided
on axles 212, which rollers 214, in turn are loosely fitted in
elongated openings 215 of said elevator rack 211, this elevator
rack is made to rise and fall with each rotation of the aforesaid
axles 212. To this elevator rack 211 standards 216 are provided,
and to a retaining plate attached to the top of said standards wing
pieces 219 of a horizontal bar 218 are mounted. Two pairs of bolts
220 are freely fitted piercing the horizontal bar 218 and its wing
pieces 219, and by intervening springs 221 between the head of the
bolts 220 and the wing pieces 219, the horizontal bar 218 is
coupled with the standards 216. Thus, when the blade 222 mounted in
the horizontal bar 218 is to cut the bag body 6, the standards 216
that are held by the elevator rack 211 compresses the springs 221
and through the intervention of the bolts 220 descend somewhat more
than the blade 222 as to result in the blade edge being strongly
pressed in contact with the bag body 6 on account of the resilience
of the spring 221. This blade 222 is disposed in the transfer
section of the bag body 6, that is, in the neighborhood directly
above the rear roller 208 of the conveyor belt 209, and its body
proper is at all times heated to a suitable temperature by
electrothermic means. For this purpose, an electrothermic means 223
is provided, which makes possible simultaneously with the cutting
of the bag body the heat sealing of the cut edges. Further, also
for the purpose of holding that portion along both sides of the
line of cut and cooling the edges at the time of heat sealing and
cutting, disposed on both sides of the edge of the blade 222 and
separated therefrom by narrow gaps are provided a pair of pressure
pieces 224 for the purpose of cooling capable of moving in unison
with the blade 222. Water pipes 225 are connected respectively to
these pressure pieces 224 for feeding cold water from one side and
discharging the heated water to the other side. A pressure plate
226 is provided forward of the blade 222 at a distance equivalent
to the width of one bag, the mounting of said pressure plate 226
being accomplished exactly as in the case of the aforesaid blade
means. By means consisting of standards 227, a retaining plate 228,
a horizontal bar 229, wing pieces 230, bolts 231 and springs 232
the pressure plate is mounted resiliently. It is desirable to
provide at the lower face of the pressure plate 226 a cushion 233
such as of silicon rubber that does not stick to the cut portions
of the bag material. Also, a wooden platen 234 is provided
contiguous to the inner side of the conveyor belt 209 opposite the
pressure plate. This pressure plate 226 and the platen 234 are so
constituted as to be adjustable with regard to their positions in
accordance with the width of the bag. In case of the pressure plate
226, this is made possible by providing for the lateral movement of
the standards 227, which support the pressure plate 226, along a
guide rail 235 of the elevator rack 211 and for securing the above
standards at any optional position. On the other hand, the platen
234 can be adjusted as to its position by a lateral movement of the
platen along a guide bar 236 mounted in the machine frame. Further,
237 are a set of superposed belts that have been provided forward
of the conveyor belt 209 and have been provided for the purpose of
removing the bags that have been conveyed by the conveyor belt
209.
In the hereinbefore described apparatus, when the delivery rollers
202 are rotated, since simultaneously with the travel of the belts
203, 237 and the conveyor belt 209, which cooperate therewith, the
axles 212 rotate and the elevator rack 211 is caused to make
up-and-down movements, if the bag body 6 is introduced to the
delivery rollers 202 and between the belts 203, the bag body 6 is
fed forward at a predetermined speed, and its tip is transferred to
the top of the conveyor belt 209. Then, as the elevator rack 211
approaches the final stages of its descending movement, momentarily
the traveling bag body is pressed down by the pressure pieces 224
provided for purpose of cooling and since simultaneously the bag
body 6 is pressibly contacted with the blade 222, the bag body is
cut by means of burning action at the line of contact of the blade
while simultaneously the cut edges are closed by heat sealing at
the cut edges of the top film and the bottom film. Instantly
thereafter the pressure pieces 224 are provided for purpose of
cooling and the blade 222 makes an ascending movement. Thus, since
the pressing and cutting of the bag body 6 is completed almost
instantaneously, even if in the meantime the bag body material is
being continuously fed, as a matter of fact, there is no trouble
caused at all. In addition, the fused material that adheres to the
blade edge being burned up by itself and disappearing, the repeated
use of the blade without further ado is possible without the
attendance of any trouble.
When the continuous belt-like material is in this manner cut into
predetermined widths starting at one end and the cut edges thereof
are heat sealed, as a result of the fact that a unit width of a bag
body leaves the bag body material and is placed independently upon
the top of the conveyor belt 209, the cut edges become spaced apart
automatically from each other for an S distance. Then, during the
descent of the elevator rack 211 the cut and heat sealed edges are
pressed between the pressure plate 226 descending from the top and
the platen 234 disposed on the underside of the conveyor belt.
Thus, inasmuch as it would be inconvenient to have unsatisfactorily
heat sealed portions around that portion which is somewhat thicker
than the other portions on account of the male and female ribs 9,
10 being located inside the bag body at this point, in order to
preclude the possibility of such unsatisfactorily heat sealed
portions to occur, pressure is applied to ensure the maintenance of
a state of positive adherence of the cut edges. The bags which have
been thus produced after being removed one by one from one end of
the apparatus via the belts 237 and collected together are ready
for use.
In using these bags, by cutting the bags at the top f and opening
up the engagement of the male and female ribs, the bag is ready to
be filled with whatever it is to be filled with. After the bags are
filled the male and female ribs 9, 10 are again occluded, and if
necessary, the mouth which was opened by cutting may be again
sealed using a heat sealer.
While the invention has been described with particular reference to
specific embodiments, it is to be understood that it is not to be
limited thereto, but that changes may be made therein without
departing from the scope of the invention which is defined in the
appended claims.
* * * * *