U.S. patent number 3,788,033 [Application Number 05/272,863] was granted by the patent office on 1974-01-29 for packaging machine.
This patent grant is currently assigned to Tetra Pak International AB. Invention is credited to Sven Torsten Jerre, Bjorn H:son Linde, Kjell Halvard Martensson, Jan-Frederik Palsson.
United States Patent |
3,788,033 |
Martensson , et al. |
January 29, 1974 |
PACKAGING MACHINE
Abstract
A packaging machine for successively erecting a package blank on
a mandrel and subsequently folding and sealing the bottom members
of the blank while the mandrel is moved intermittently from one
station to another in which means are provided for folding in the
first and second bottom flap members, prior to sealing, as the
mandrel moves from one station to the next.
Inventors: |
Martensson; Kjell Halvard
(Lund, SW), Linde; Bjorn H:son (Lund, SW),
Palsson; Jan-Frederik (Lund, SW), Jerre; Sven
Torsten (Lund, SW) |
Assignee: |
Tetra Pak International AB
(Lund, SW)
|
Family
ID: |
20263034 |
Appl.
No.: |
05/272,863 |
Filed: |
July 18, 1972 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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227812 |
Feb 22, 1972 |
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Foreign Application Priority Data
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Mar 25, 1971 [SW] |
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3864/71 |
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Current U.S.
Class: |
53/565; 53/370.9;
493/133; 53/387.4; 493/184 |
Current CPC
Class: |
B29C
65/7882 (20130101); B29C 66/81465 (20130101); B29C
66/43122 (20130101); B65B 3/025 (20130101); B29C
66/836 (20130101); B29C 66/8221 (20130101); B29C
66/73921 (20130101); B29C 66/72328 (20130101); B29C
65/103 (20130101); B29C 66/1122 (20130101); B29C
66/3494 (20130101); B29C 66/8432 (20130101); B29C
66/81811 (20130101); B29C 66/849 (20130101); B29C
66/8161 (20130101); B29C 66/8322 (20130101); B65B
43/10 (20130101); B29L 2031/7166 (20130101); B31B
50/52 (20170801); B31B 50/322 (20170801); B29K
2711/123 (20130101); B29C 66/8226 (20130101); B31B
50/004 (20170801); B29C 66/8242 (20130101); B29C
66/8324 (20130101) |
Current International
Class: |
B31B
5/74 (20060101); B31B 5/00 (20060101); B65B
43/00 (20060101); B65B 3/02 (20060101); B65B
3/00 (20060101); B65B 43/10 (20060101); B65b
003/02 (); B65b 043/26 (); B65b 007/20 () |
Field of
Search: |
;53/186,375,201,388,373,183,381R ;93/39.2,59R,59CE,49R,55 |
References Cited
[Referenced By]
U.S. Patent Documents
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3248841 |
May 1966 |
Heffelfinger et al. |
3699743 |
October 1972 |
King et al. |
3200557 |
August 1965 |
Schwenk |
3535848 |
October 1970 |
Gellatly et al. |
2841942 |
July 1958 |
Wills et al. |
3619979 |
November 1971 |
Martensson et al. |
R26699 |
October 1969 |
Austin, Jr. et al. |
|
Primary Examiner: McGehee; Travis S.
Assistant Examiner: Culver; Horace M.
Attorney, Agent or Firm: Pierce, Scheffler & Parker
Parent Case Text
This is a division, of application Ser. No. 227,812 filed Feb. 22,
1972.
Claims
We claim:
1. A packaging machine for the production of filled and sealed
packages from package blanks of carton material having a lining of
thermoplastic material, the package blanks being provided with
crease lines for providing foldable bottom closure elements, said
machine comprising a stud wheel having a plurality of mandrels
extending radially therefrom, means for intermittently rotating
said stud wheel to successively position each mandrel at a series
of successive stations, means at the first station for erecting a
package blank into tubular form and for disposing the erected blank
onto the mandrel stationed thereat, means at the second station for
breaking the crease lines of the bottom closure elements of the
erected blank, means at the third station for heating the bottom
closure elements to plasticize the thermoplastic lining thereof,
means at the fourth station for sealing the heated bottom closure
elements together, means for withdrawing bottom sealed package
blanks from each mandrel, and means for filling, closing and
sealing the filled packages, said machine further comprising means
located between the third and fourth stations for folding the
bottom closure elements together, said means including a first and
a second folding arm, means for pivotally mounting each arm on the
frame of the machine, a connecting link pivotally connected at each
end to one of said folding arms, said first folding arm being
pivoted as an erected blank disposed on a mandrel passes from the
third station to the fourth station whereby said first folding arm
folds a first bottom closure element inwardly of the erected blank,
said link causing said second folding arm to pivot as said first
folding arm is pivoted so as to bear against a second bottom
closure element opposed to said first bottom closure element so
that said second bottom closure element is folded inwardly to lie
against first closure element.
2. A packaging machine as claimed in claim 1 wherein the distance
between the pivot of the first folding arm and the pivot of the
link thereto is greater than the distance between the pivot of the
second folding arm and the pivot of the link thereto, whereby the
folding arms approach each other as the first arm is pivoted by the
erected blank.
3. A packaging machine as claimed in claim 1 and further comprising
means for resiliently urging said first and second folding arms
apart, whereby the folding arms are separated after a folded blank
has moved to the fourth station so as to receive the next
succeeding unfolded erected blank.
4. A packaging machine as claimed in claim 1 wherein said first
folding arm is provided with a striking edge which engages the
erected blank as the blank moves from the third station to the
fourth station thus pivoting said first folding arm and the second
folding arm.
Description
The present invention refers to a packaging machine for the
production of filled and closed packages from blanks of material
lined with thermoplastic, e.g., plastic lined cartons, which are
prepared in advance and are provided with crease lines to
facilitate the production of folds, whereby the said packaging
machine comprises intermittently rotatable stud wheels which carry
studs, arrangements for the erection of package blanks in tubular
form and for feeding the erected package blanks onto the studs,
devices for shaping and sealing of a base on the package blanks fed
onto the studs and securing devices preferably provided on a
conveyor which is capable of moving in the horizontal plane, an
arragement for moving the package blanks processed on the studs and
provided with a base to the retaining devices on the said conveyor
as well as devices for folding, filling and closing the packages
lowered into the said retaining devices.
In the field of packaging technology it has long been known how to
make packages with a so-called "gable top." They are produced in
almost all cases from prepared blanks which are advantageously
provided with a crease line pattern in order to facilitate the
erection of the packages and their shaping by folding of the panels
forming the top and the base to their final position. The said
package blanks are nowadays generally lined with a thermoplastic
material such as polythene, whereby the thermoplastic layer serves,
on the one hand, in order to make the package impermeable to
liquids, and, on the other hand, in order to seal the package with
the aid of heat and pressure so that it is permanently held
together in the erected position.
The said packages have found their most important use as packages
for liquids, in particular for milk, and various machines have been
designed for the production of the packages. Packaging machines
comprising indexable stud wheels on the studs of which previously
produced package blanks are arranged to be mounted and on which the
package blanks are provided with a base while the studs pass a
number of processing stations are as such known, and it has also
been previously known how to transfer the completely processed
package containers from a stud wheel to a conveyor which removes
the package containers along a track, whereby the sections forming
the top of the package containers are folded, the package
containers are filled with the intended charge whereupon the said
sections forming the top are finally folded inward over the
openings of the filled package containers and are sealed in a
permanent manner.
The disadvantages of the hitherto known packaging machines of this
type were due to the fact that the production capacity of each
production line is low. A considerable improvement in this respect
can be achieved by a packaging machine in accordance with the
invention which is characterised in that the stud wheels are
arranged in pairs parallel to one another and are so arranged that
a synchronous intermittent rotary movement is imparted to them by a
common drive unit, in that the axis or axes of rotation are located
vertically above the conveyor belonging to the pair of stud wheels
and in that the plane of rotation of the stud wheel is
perpendicular to the plane of motion of the conveyor. The reason
why improvements can be brought about by a machine in accordance
with the invention consists in that two or more stud wheels can be
associated with one and the same conveyor track inasmuch as the
stud wheels are located transverse to the conveyor or conveyor
track. If a number of stud wheels located in a conventional manner
were to be associated with one and the same conveyor track, the
said track would come to be very long owing to the considerable
diameter of the stud wheels and all processing stations and their
drives would, in addition, have to be duplicated. On the other
hand, with the arrangement of the stud wheels in accordance with
the invention, the drive of the processing stations need not be
duplicated since the stud wheels are located close to one another
and parallel to one another.
A further advantage of the packaging machine in accordance with the
invention consists in the fact that package blanks of different
standard lengths may be used without setting of any stop lugs on
the studs since the machine is provided with an automatic container
stop with the aid of which the position of the containers on the
studs is adjusted in such a way that the containers are located
correctly. This device for adjusting the position of the package
blanks on the studs is characterised by pivotable wings arranged at
a distance from one another which are so equipped that they can be
swung towards one side face of a stud fed towards the middle of the
device.
A further advantage of the packaging machine in accordance with the
invention consists in that the arrangement for heating the sections
which form the base does not have to be raised and lowered during
each operation, since the said arrangement is provided with a
deflector which distributes hot air in the required manner along
the surface of the sections forming the base. The said heating
device is characterised in that it is provided with a heating
chamber in which air is heated to a temperature above the
plastification point of the thermoplastic material, in that the
said heating chamber is bounded by holes or ducts which are
provided to pass through and direct a current of hot air coming
from the heating chamber, and in that a deflector is provided,
which possesses a number of oblique wall faces so arranged as to
deflect the current of hot air from at least some of the said holes
or ducts so that this current of hot air is given a substantially
different direction than the one in which it flowed directly after
passing through the holes.
a further advantage of the packaging machine in accordance with the
invention consists in that the base sections are folded inward by
means of a folding device without drive, which is characterised in
that the said device is provided with a first and a second
rotatably located folding arm, both of these folding arms being
rotatably located in a common base which is rigidly connected with
the engine base, whereas the said folding arms are mutually
connected by means of a link rotatably located in the two folding
arms, this link being so arranged as to transmit the movement of
the said first folding arm to the said second folding arm in such a
way that the first folding arm acts on the second folding arm in
the course of its movement.
A further advantage of the packaging machine in accordance with the
invention consists in that the top sealing operation can be carried
out by means of link controlled movable sealing jaws, which are
characterised in that the said sealing device has two pairs of
pressure jaws each with a movable and a fixed pressure jaw, the
said pairs of pressure jaws being so arranged as to operate
synchronously, in that the movable pressure jaws in each pair of
pressure jaws are joined to one another by means of linkage arms
which are rotatably located in one or the other of the movable
pressure jaws, and by a joint, mainly horizontal shaft which is so
arranged that it can be located in a first and in a second position
in the vertical plane, whereby the pair of pressure jaws is closed
when the said shaft is in its first, upper position, and the
pressure jaws are open when the said shaft is in its lower, second
position.
A particularly advantageous embodiment of the invention is
described below with reference to the attached diagrammatic drawing
in which
FIG. 1 shows a perspective view of the machine.
FIG. 2 shows a diagrammatic side view of the machine.
FIG. 3, 3a and 4 show an automatic positioning device for the
containers.
FIG. 5 shows a heating device.
FIG. 6a, 6b, 7a, 7b and 7c show a folding device.
FIG. 8 shows a pressure jaw system, and
FIG. 9 shows a package blank.
With the packaging machine in accordance with the invention
packages are produced from previously manufactured package blanks
consisting of carton lined with thermoplastic or a similar
material. An example of such a package blank is shown in FIG. 9
where the package blank 4, which in the initial position is flat,
has been erected so as to form tube with square cross-section. The
production of the package blank 4 is effected by stamping out a
sheet of the carton material lined with plastic along the desired
lines, possibly after printing, and by providing crease lines 103
which facilitate folding of the package blank. After stamping of
the carton blank its two longitudinal edges are joined so as to
form a longitudinal joint 104 so that the package blank can be
erected in tubular form.
The base end 35 of the package blank 4 is provided with two
relatively large, rectangular base end sections 105 and 106 and
with two smaller triangular base end sections 107 and 108, which
are connected with the larger sections 105 and 106 by means of the
fold-back sections 109 and 110. All the said end sections are
separated from one another and from the container body 111 by means
of the crease lines 103 provided in the packaging material and
facilitating the folding process.
The upper part 113 of the package blank has basically the same
folding pattern as the base part, but since the top is not to be
folded so as to form a flat top but a so-called gable top, the
dimensions and angles of the sections forming the top are
different.
The section 113 forming the top is also joined to the sealing
section 112, which is so designed as to be joined in a flat fin, in
which the sealing sections are sealed to one another so as to form
a tight and durable sealing joint.
Both the top part and the base part are formed in essentially the
same manner, and for simplicity's sake only the folding operation
for the base part will be described here, which is effected in such
a way that the smaller, triangular sections 107 and 108 are folded
inward over the aperture of the package blank, whereupon the larger
sections 105 and 106 are also folded inward over the aperture of
the package blank, while at the same time the fold-back sections
109 and 110 are folded inwards towards the triangular sections, so
that on completion of the folding operation they are between and in
contact with the smaller and the larger sections, in which position
the sections are sealed to one another with the aid of heat and
pressure.
As mentioned above, the top part of the package is formed in
essentially the same way but with the difference that, owing to
their dimensions, the sections forming the top cannot be folded
entirely inward over the aperture of the container but only to a
position, in which the sections which face each other in pairs,
meet one another. The sealing sections 112 are folded towards one
another so as to form a flat fin, whereby the smaller sealing
sections are folded inward, in the manner of a bellows, between the
larger.
For the sake of clarity, the packaging machine is described below
initially in general terms, mainly with reference to FIGS. 1 and 2
of the drawing, whereupon certain constructional parts or elements
which co-operate with one another and are characteristic of the
machine in accordance with the invention are described
separately.
GENERAL DESCRIPTION OF THE MACHINE
The flat package blanks 4, which have not yet been erected, are
discharged from the magazine 2 while at the same time the package
blanks 4 are erected in a tubular form, which in the present case
has a square cross-section.
By means of the feeder device 3, which consists of a rotatable
chain provided with carriers 9, the erected package blanks 4 are
pushed onto a stud 5 provided on the stud wheel 6, the said stud
having been moved in position opposite the feeder device. (In the
drawing this position is designated I). Once the package blank 4
has been pushed onto stud 5, the stud wheel 6 is indexed, and since
the indexing angle in the present case amounts to 60.degree., the
stud wheel rotates by 60.degree. in a counter-clockwise direction
until it reaches position II, whereupon the stud wheel stops
again.
In position II, the base end 35 of the package blank 4 mounted on
stud 5 is centrally opposite a folding device 7 controlled by an
actuater 30, preferably a pneumatic cylinder. With the aid of the
actuater 30, the folding device 7 is moved towards the base section
35 of the package blank 4, the said base section projecting from
stud 5, whereby flaps 50 of the folding device 7 are folded inward
towards the base section of the package blank 4 with a view to
folding or "breaking" the crease lines previously provided in the
base section of package blank 4. The folding process is, however,
interrupted before the wall section of the package blank, which
forms the base, has been completely folded inward to its final
position, and owing to the elasticity of the material, section 35
of package blank 4 which projects from stud 5 returns substantially
to the position in which it was prior to the folding operation.
When the folding operation is completed, the stud wheel 6 is again
indexed and stops in position III, in which position the folded end
section 35 of package blank 4 is centrally opposite a heating
device 8. Through the heating device 8 hot gas, preferably air, is
blown against the raised end section 35 of package blank 4, whereby
the elements of the end section, which are intended to act as
sealing sections are heated to such an extent that the
thermoplastic liner softens. Thereupon the stud wheel 6 is again
indexed and moves to position IV.
While the stud wheel 6 with stud 5 moves from position III to
position IV, section 35 of package blank 4 projecting from stud 5
comes into contact with a folder 36 which puts together two
opposite sides 105 and 106 of the end wall section of package blank
4, while the two remaining end wall sections 107 and 108 are folded
between the above mentioned end wall sections in the manner of a
bellows. When the stud 5 has reached position IV, a cooled pressure
plate 10, which can be displaced by an actuater 29, preferably a
pneumatic cylinder, is pressed against the folded base section,
whereby a substantially plane package base is formed. By cooling
the heated parts of the end section 35 at the same time as the
sections of package blank 4 which form the base are pressed
together between the pressure plates 10 and the end of stud 5, the
heated thermoplastic layer is caused to stiffen once the heated
faces have been combined by surface fusion, whereby the sections
forming the base are held together in the compressed position so as
to form a plane, liquid-proof base. In order to ensure a good seal
it is important for the folded base sections to be pressed against
one another with great force, and it is advisable to make use of
pressures up to several tons, since pressures of this magnitude
cause effective flow of the plastic in the sealing zone and closure
of any leakage channels which may occur when overlapping layers of
material are joined.
Once the base has been pressed on the stud wheel is indexed to
position V, for which position no operation is provided, so that
the container 33 which has been given a base is turned, after a
period of time corresponding to one indexing period, to position
VI, in which the stud 5 is directed downward.
In position VI the container 33 is pulled from stud 5 by means of a
pull-off device 11 which is vertically deplaceable and has at its
front part a suction head 37, which can be connected to a vacuum
source not shown here.
The pulling-off operation is effected by raising the pull-off
device 11 with the aid of an actuater 38 until its suction head 37
comes into contact with the plane base of container 33. When the
suction head 37 has come into contact with the base or before this
contact is brought about, the suction head is connected with a
vacuum source not shown here, as a result of which the suction head
is attached to the base of container 33. When the pull-off device
11 is thereafter caused to move downward, the container 33 is
pulled from stud 5 and lowered between the retaining devices which
are arranged on an intermittently movable chain conveyor 13, by
means of which the containers 33 pulled from the stud wheel 6 are
cuased to be transported in a substantially horizontal
direction.
The stud wheel 6 is indexed after completion of the pull-off
operation to position I, in which a fresh package blank 4 is pushed
on stud 5 by the feeder device 3.
In the above description a method of operation has been reported in
which a stud wheel 6 carries out a complete indexing cycle, but
during each indexing pause operations are of course carried out in
all positions with the exception of position V, and this means that
a completely processed container 33 is pulled off during each
indexing pause while at the same time a fresh package blank 4 is
mounted on stud 5. Naturally the time between two consecutive
indexing operations must be so selected that all operations in the
various positions can be completed.
Since two or more stud wheels 6 are simultaneously associated with
a conveyor 13, two or several containers 33 provided with a base
are at all times transmitted from the stud wheel 6 to the conveyor
13 by means of two or more pull-off devices 11. With the machine
here described each conveyor 13 is associated with two stud wheels
6, so that two containers 33 provided with a base are transmitted
to the conveyor 13 during each indexing operation. Since the
conveyor is supplied with two containers 33 during each indexing
operation, the container must be moved by two package divisions
during each indexing operation, and all processing stations for
folding the tops of the containers and for filling and closing the
containers 33 must be duplicated. However, since the said
processing stations are situated in lateral juxtaposition, a common
drive mechanism can be used for each pair of devices.
Each conveyor 13 consists of two parallel endless chains which are
provided with retaining devices 97 whereby the retaining devices
located centrally opposite one another on the two chains form
between them a space 98 which is so designed that an upright
container 33 can be placed within it. When a container 33 is pulled
from stud 5 by the pull-off device 11 and moved downward, it is
introduced between the two chains 13 and into the space 98 defined
by the retaining devices 97. For this to be possible, the movement
of the conveyor chain must of course be synchronised with that of
the stud wheel so that the conveyor chain 13 moves forward by two
retaining device divisions during each indexing operation of the
stud wheel 6 while fresh empty spaces bounded by the said retaining
elements 97 are always directly below the studs 5 in position
VI.
When the container 33 is introduced into the space defined by the
retaining devices 97, the suction head 37 releases its hold and is
separated from the container 33 which is now in position within the
holding devices 97 connected to the conveyor chain 13. As stated
above, the conveyor chain is, during each indexing operation, moved
on in stages towards the right in FIGS. 1 and 2, whereby the height
position of the container 33 is determined by causing their bases
to slide along a track 12 the height of which is adjustable.
At station A the top section of the containers is folded by means
of a folding device 14 attached to a yoke 25 which can be raised
and lowered. The folding operation is effected by folding the
triangular flaps 40 which form part of the folding device 14
inwards against two opposite triangular side sections of top
section 41, while at the same time the remaining side sections are
folded inward over the aperture of the container and take up
between themselves the two said triangular sections. However,
folding has only the purpose of bending or "breaking" the crease
line pattern which has been provided on the package blank and which
is intended to define the folding pattern necessary for sealing the
top of the container, and hence the folding operation is not
completed but the folding device 14 is raised to its upper position
once the crease line pattern has been bent.
After indexing of the stud wheel 6 and displacement of the conveyor
chain 13 by one stage, the folded containers 33 are at station B,
i.e., directly below the charging device 16, by means of which a
measured quantity of the charge is introduced into the containers.
Filling of the containers 33 is effected in such a way that the
containers are raised about the filling tubes 16 by means of
lifting devices 1 which grip the upper edge of the containers,
while they are controlled in a sideways direction by the retaining
devices 97, whereupon the containers 33 are again lowered to their
original position by means of the lifting devices 1 in the course
of charging. Thereafter the filled containers are moved in stages
and synchronously with the indexing mechanism to station C, where
the aperture of the container is directly below the top heating
device or "top heater" 17. Just like the base heating device 8, the
top heating device 17 consists of a heating device provided with
holes, whereby hot air is blown through the said holes which are
arranged in such a pattern that the heat reaches only those parts
of top section 41 which are intended to be sealed against one
another. The hot air is obtained by burning a combustible gas in a
special combustion chamber, whereupon air is blown through the
combustion chamber and out through the holes provided in the
heating device. Heating of the sealing sections of top section 41
of container 33 is effected in such a way that the top heating
device 17 is lowered into and over the top sections of the
containers 33, whereby the heated air, which is blown out through
the said holes, impinches on the sealing sections lined with
thermo-plastic material mainly at a right angle. The thermoplastic
material is quickly heated to the point of plastification whereupon
the top heating device 17 is raised to a position outside the
apertures of the containers 33, and the containers 33 are moved
from station C to station D, while the sealing section of top
section 41 is folded inward over the apertures of the containers
with the aid of control tracks 114. Folding inward of the top
sections 41 of containers 33 is effected in such a way that the
said triangular sections are folded inward in the manner of a
bellows between the outer sections forming the top whereby the
sealing sections are combined in a fin which at station D is
pressed between co-operating pressure jaws 18, which are cooled.
Since the plastic is heated at the commencement of the sealing
operation, the surfaces between the combined heated plastic layers
are fused, as the result of which the sealing action which is
achieved after compression and cooling at station D is very
powerful. After station D a further station may be provided, at
which station labelling, date marking or similar operations may be
carried out with the aid of stamping mechanisms, embossing
mechanisms, labelling devices etc.
At station E at the end 19 of the conveyor chain the retaining
devices which surrounded the containers during transportation by
means of chain 13 are separated and the completed packages are
removed from the packaging machine.
The packaging machine is driven with the aid of an electric motor,
which may be provided with a gearbox of wormwheel or spurwheel
type. The output shaft of the motor is connected by means of a belt
to a mitre gear, the output shaft 52 of which drives the main shaft
21 of the machine by means of a transmission chain. On the shaft 52
are provided cams 20 with the aid of which the pump pistons of the
filler device 16 are actuated. Since a packaging machine is
designed for the production of packages of different heights and
hence of different volumetric content, there are several different
cams (in the present example four, since the packaging machine is
intended for the production of four different package sizes), which
are so arranged that the desired cam can be moved into the working
position. On shaft 52 there is also another set of cams 46 by means
of which the lifting devices 1 are driven and controlled. Since the
packaging machine here described has twin-conveyor tracks 13 with
appropriate stud wheels and processing stations, a further shaft 52
with appropriate cams 20, 46 is found on the other side of the main
shaft 21.
The main shaft 21 drives two mitre gears 24 the output shafts 49 of
which drive the indexing mechanisms 23 of the stud wheel. The main
shaft 21 also drives the cam discs 38 fof the pull-off devices 11,
the cam disc 31 of the folding device 14 and the cam disc 32 of the
top heater 28.
The sealing jaws 18 can be driven either by means of cam disc 28
which is associated with main shaft 21 or with the aid of a
separate drive cylinder.
After this introductory general description of the packing machines
operation, a more detailed description is given below in order to
describe some of the vital systems of the packaging machine and the
manner in which these systems co-operate with a view to achieving
the desired result, i.e. a cheap and rapid packaging machine which
in addition exhibits good operational characteristics.
A. SYSTEM FOR ADJUSTING THE POSITION OF THE PACKAGE BLANKS ON THE
STUDS
With packaging machines of the type described above previously
produced package blanks 4 are erected in tubular form, whereupon
they are pushed onto a stud 5. In order to be able to use only one
type of studs, all package blanks 4 have the same cross-sectional
area, as the result of which all packages have the same base format
and cross-sectional area. In order to be able to vary the size of
the packages it is therefore necessary to vary the height of the
packages and package blanks of different height are therefore
provided.
As previously mentioned the package blanks 4 are moved so far over
the studs 5 that the ends with the section 35 forming the base
project beyond the front edges of the studs. Since the sections 35
forming the base are to be folded along prepared crease lines 103,
their crease lines must therefore substantially coincide with the
fed front edges of the studs.
Feeding of the studs is effected by means of a previously described
arrangement which comprises a.o. an endless chain 3 with carriers
9. This mounting or feeding action of the package blanks 4 on studs
5 is of course effected in such a way that the package blanks are
located on the studs in a substantially correct position, but since
it is important for the package blanks to be located in an exactly
correct position and since they must not be pushed further over the
studs 5 during the subsequent operations it is necessary to provide
the studs with some form of stop lug which prevents the package
blanks 4 from being pushed on further and which is so located that
the package blanks 4 are correctly placed on the studs 5, when
their inner edges rest against the said stop lugs.
It used to be customary for each stud 5 to be provided with a stop
lug capable of being displaced along the stud as well as of being
locked in position, but this made it necessary, when converting the
machine from one package size to another, to change all the stop
lugs individually, which wastes a lot of time, but with the aid of
the arrangement in accordance with teh invention such individual
conversion is no longer necessary, and no action on the part of the
machine operator is in fact required in order to change the
position of the stop lugs when altering the package size.
The above mentioned automatic arrangement for the adjustment of the
position of package blanks 4 on the studs 5 is characterised in
that spaced, pivotable wings 63 are provided, which are so designed
that they can be swivelled inward towards one side face of a stud 5
fed centrally towards the device, and the invention is further
characterised in that the said wings are movably located on a
common shaft 60 which is so designed as to be capable of causing a
rotary movement in both directions of rotation, while the elements
rigidly connected with shaft 60 support a carrier pin 75 which is
designed to slide within a guide aperture 74 provided within the
said wings 63 which are in addition subject to tension springs 65,
these having the tendency of moving the wings 63 against the studs
5.
The said device or system for automatic adjustment of the position
of the package blanks 4 on the studs 5 is shown in FIGS. 3, 3a and
4, and a more detailed description of this system and its function
is given below with reference to these figures.
The side walls of the studs 5 are not plane but they are provided
with recesses 71, and in one of these recesses of each of the studs
is located a track 66 with a groove 69 which is transverse in
respect of the longitudinal direction of the stud. The distance
between each of these grooves and the front edge 72 defines the
correct push-on length for the different package blank sizes. The
automatic container positioning system or container stop itself is
mounted on a beam 70 which is firmly connected with the machine
frame, and it consists of a shaft 60 which can be actuated by means
of a pneumatic cylinder 62, the said shaft 60 being joined to the
actuating rod of the pneumatic cylinder by means of a rotatable arm
61. The shaft 60 is rotatably mounted within bearings fixed within
the said beam 70, and shaft 60 supports a number of wings 63 which
are capable of rotation in respect to the shaft. The wings 63
(a,b,c) are separated from each other by spacer rings 73 in such a
way that each of the wings is placed centrally opposite the groove
69 and a stud 5 fed centrally towards the adjusting device, whereby
each of wings 63 is associated with a special groove. In FIG. 3a
one can see partly in cross-section how the wings 63 are provided
with a long and narrow guide aperture 74 into which a pin 75 is
introduced, which is firmly associated with shaft 60. Each of the
movably arranged wings 63 is, in addition, connected with a section
64 by means of a tension spring 65, the said section 64 being
firmly attached to beam 70. The rear end wing 76 is not movable in
relation to shaft 60, unlike the wings described above, but it is
firmly connected with the said shaft, and in the embodiment shown
here, the end wing 76 consists of a part of arm 61.
The automatic container positioning system werks as follows.
When a package blank 4 is mounted as the previously described
station I on a stud 5 centrally set towards the feeder device, the
feeder device is so adjusted that it does not move the package
blank 4 entirely to the correct position but locates the package
blank 4 a few millimetres too high on the stud 5. At the following
station II the upper section 35 of the package blank is folded by
means of a folding device 7 in the manner above described, and this
folding operation causes the package blank to be subjected to a
pressure which tends to push the package blank 4 further over the
stud 5.
However, at station II there is the automatic adjusting device for
locating the package blank 4 on stud 5, and before the folding
device 7 exerts is pressure on the projecting section 35 of the
package blank, the shaft 60 is turned, with the aid of pneumatic
cylinder 62 and rotary arm 61 into a position, in which the wings
63 are swivelled inward towards the stud 5, the wings 63 being
retained in the said swivelled inward position during the entire
folding operation.
As the result of the turning movement of shaft 60, the pin 75 is
turned from its front position in guide apertures 74 and, as the
result, releases the wings 63, which with the aid of tension
springs 65 are swivelled inward towards the stud 5 which has been
fed forward. As can be seen in FIGS. 3 and 4, the two front wings
63 (a,b) impinch upon the wall surfaces of the mounted package
blank 4, in the case here illustrated, and they are stopped by
these surfaces which prevent further turning of the wings 63 (a,b).
The third wing counted from the front (63c), however, is not
stopped by the package blank inasmuch as the latter is not pushed
onto the stud 5 to such an extent that its front edge reaches this
wing. Hence, the wing 63c is swivelled further towards stud 5,
whereby the movement of the latter is finally stopped when the
front part 67 of the wing reaches the bottom of groove 69 in track
66 which is associated with this wing.
When the package blank 4 is pressed further onto stud 5 during the
immediately subsequent folding operation, the front edge of package
blank 4 is pushed agaist wing 63c, as a result of which the crease
103 in the package blank are located in the correct position with
respect to the front edge 72 of stud 5.
In order to achieve better control of the front edges of the
package blank it is advisable to provide the wings 63 with a
transverse rib 68 which is located over the front edge of the
package blank, when the package blank 4 is pushed to its correct
position on stud 5.
In the present example it may be assumed that the packaging machine
is intended for the production of a package with a capacity of 2dl,
3dl, 5dl and 1l, whereby the wing 63a corresponds to a package
blank for packages with a capacity of 2dl etc. The wing 76 which is
not provided with a spring always corresponds to the package blank
with the largest volume capacity, i.e., 1l in the present case.
It is, of course, not absolutely necessary to provide the wings 63
with ribs 68, nor is it necessary for each stud 5 to be associated
with the above rib 66 which is provided with a groove, but it has
proved valuable in practice to be able to control the front edge of
the package blanks with these aids, particularly when the package
blanks are made of thin material.
B. BASE HEATING DEVICE
With packaging machines of the type previously described the base
of the packages is formed by folding the sections 35 which form the
base and project from the studs 5 towards each other with two of
the opposite sections being folded between the remaining two
opposite sections in the manner of a bellows. The sections 35 which
form the base and are folded inward are retained in the
folded-inward position by heating the thermoplastic lining of the
package blank 4 in the region of sections 35 which form the base,
until plastification occurs, whereupon the thermoplastic material
lining the surfaces of the sections is bonded after folding by
surface fusion so as to form a permanent seal.
The sections which are to be heated to the sealing temperature are,
in this context, generally referred to as sections 35, but they
consist, as can be seen from FIG. 9, of the outsides of the
triangular sections 107 and 108, the outside and inside of the
triangular fold-back sections 109 and 110 and of the inside of the
rectangular sections 106 and 105 with the exception of the
triangular parts which as regards size and location correspond to
the triangular sections 107 and 108. The system for heating the
base-forming sections 35 of the package blanks is provided with a
heating device by means of which heating air or gas can be blown
against selectively chosen zones of the base-forming sections 35 of
package blanks 4 with a view to activating the adhesive capacity of
the thermoplastic lining within the said zones, and the said
heating device is characterised in that it possesses a heating
chamber in which air heated to a temperature above the
plastification point of the thermoplastic material is supplied from
a combustion chamber not shown here, wall plates bounding the said
heating chamber, at least some of the said wall plates being
provided with holes or ducts which are so designed as to pass
through and direct a current of hot air coming from the heating
chamber, and a deflector which is provided with a number of oblique
wall surfaces, which are arranged to deflect the hot air current
from at least some of the said holes or ducts so that this hot air
current is given a substantially different direction than that in
which it flowed directly after passing through the holes.
It is as such known to heat the base-forming sections of the
package blanks 4 mounted on studs 5 by means of radiation heat or
hot air which is blown towards selected areas of the base-forming
sections 35. The heating devices hitherto used have consisted of
units which could be raised and lowered and were so arranged that
they could be partly introduced into those parts of package blanks
4 which project from the studs 5. However, in certain bases it is
difficult to arrange such movable heating devices and fixed heating
devices have been used instead, but in this case it has been
difficult to distribute the hot air to selected parts of the
base-forming sections 35 in a suitable manner.
In the present case, this problem has been solved by providing the
heating system with a deflector body 82 by means of which hot air
flowing out through specially arranged holes 80 from the heating
device is deflected by the deflection faces 81 of the deflector
body 82 so that the hot air current is mainly directed towards the
inside of section 109 and 110 and to the inside of the outer parts
of the rectangular sections 105 and 106 whereas the inner parts of
the triangular sections 107 and 108 are not heated to any
significant extent.
The outside of the triangular sections 107 and 108 as well as the
triangular fold-back sections 109 and 110 are to be heated and this
is achieved by means of special heating devices 86 which extend
downward along the sides of the package blank 4.
The heating device in accordance with the invention is shown in
FIG. 5, and the system consists of a heating chamber 83 mounted
within the machine frame, which is supplied with hot air from a
combustion chamber. The hot air is obtained by burning a
combustible gas together with air in the said combustion chamber,
whereupon the hot air supplied to the heating chamber 83 is blown
out through the holes 80 which are arranged in one end wall 85 of
the combustion chamber, whereby it is distributed in a suitable
manner. The holes 80 are so arranged that the hot air currents
emanating from the said holes 80 impinch on the deflecttor body 82
which is mounted on the end wall 85 in such a way that the
deflector faces 81 deflect the air currents emanating from the
holes 80 preferably at right angles and at the same time direct the
said air currents towards basically four different directions
towards the corner zones of the inside of a package blank 4 fed
into the heating device. The outside of the triangular sections and
the fold-back sections of the base-forming sections 35 is heated by
means of a special heating device 86 through which hot air is
delivered through the holes 88 towards the said faces of the
base-forming sections 35 of the package blank.
If it is required for the edge zones of the shorter, rectangular
section 105 (FIG. 9) to be heated on the surface of the section, a
screen 87 is provided on the baseplate 85 of the heating device. A
further row of holes 89 communicating with the heat chamber 83 is
arranged directly next to the said screen 87, whereby the hot air
currents emanating from the holes 89 are deflected by the screen 87
so as to impinch on the outside of the rectangular section 105
along the free edge of the said section.
The deflector 82 described above may advantageously consist of
metal and should be so dimensioned that the package blank 4 mounted
on the stud 5 can pass freely below the deflector 82 without
touching the latter.
C. BASE FOLDER
With packaging machines of the type here considered the bases of
the packaging containers are formed by folding the base-forming
sections 35 along a crease line pattern previously stamped into the
package blank 4 as described above. In order to facilitate the
folding operation, the crease lines are broken at station II as
previously mentioned (see FIG. 1), whereupon selected parts of the
base-forming section 35 are heated at station III in order to make
the thermoplastic lining capable of being sealed. At station IV the
section 35 folded towards each other are pressed together so as to
form a durable joint.
As can be seen from the above description of the method of
operation the base-forming sections 35 must be folded together
between stations III and IV so that they can be picked up and
pressed together between the pressure device 10 and the front face
of stud 5 on which the package blank 4 is mounted, without being
able to return to their initial position owing to their elasticity.
This combining of folding operation may in certain cases be brought
about by guide rails which gradually bring the rectangular sections
105 and 106 together, whereby the triangular sections 107 and 108
and the so-called fold-back sections 109 and 110 are folded under
the sections 105 and 106 in the manner of a bellows. Folding
together of the base-forming sections 35 with the aid of guide
rails does, however, presuppose that the package blanks 4 are so
arranged on the studs 5 that the rectangular sections 105 and 106
are oriented in the plane of movement of the studs 5. Such an
orientation of the package blanks 4 is however not desirable in the
present case since the containers 33 provided with the base would
then be disadvantageously orientated during the subsequent filling
and top sealing operations, and it is therefore necessary to make
use of an entirely different design than the one embodying the said
guide rails, which is characterised in that said device comprises a
first and a second folding arm which are capable of being
swivelled, both of the said folding arms being rotatably located in
a common base which is rigidly connected with the machine base
while the said arms are mutually joined by means of a link
rotatably located within the two folding arms, the said link being
so arranged as to transmit the movement of the said first folding
arm to the said other folding arm in such a way that the first
folding arm will drive the second folding arm in the course of its
motion. The folding device in accordance with the invention is
further characterised in that the distance between the bearing
point of the first folding arm and the bearing point of the said
link in the folding arm is greater than the distance between the
bearing point of the other folding arm and the bearing point of the
link in the folding arm, and in that one of the two folding arms,
preferably the first, is subject to the action of a tension spring
which tends to keep the two folding arms separated.
An embodiment of the folding device in accordance with the
invention will be described below with reference to FIG. 6a, 6b and
FIG. 7a, 7b and 7c in the attached diagrammatic drawing.
The folding device consists of two folding arms 90 and 91 which are
rotatably fixed in a support plate 115 rigidly connected with the
machine base, the position of the said support plate in relation to
the machine base being capable of adjustment by means of setscrews
119. The folding arms 90 and 91 are connected with one another by
means of a link 92, which at its ends is rotatably fixed within the
two folding arms at the bearing points 116 and 117. Either one of
the folding arms, preferably the folding arm 90, is connected with
a tension spring 93 attached to the machine base, the said spring
having the tendency of holding the folding arms in the position
shown in FIG. 6a and 7a.
The points at which link 92 is attached to the folding arms are so
arranged that the distance between bearing point 95 of folding arm
90 in the support plate 115 and the bearing point of folding arm 90
for link 92 is considerably larger than the distance between the
bearing point 96 of folding arm 91 in the support plate 115 and the
bearing point of folding arm 91 for the link 92.
When the stud wheel moves in the direction of the arrow from
station III to station IV, as shown in FIG. 7a, the studs 5 which
do not support any package blank 4 can pass precisely under the
folding device. However, if the studs 5 support package blanks 4,
the front edge of the package blank in respect of the direction of
movement impinches the edge 118 of folding arm 90 directly above
the transverse crease line of the package blanks which separates
the base-forming section 35 from the container body, as shown in
FIG. 6a and 7b.
When the folding arm 90 is acted upon and displaced by the package
blank 4, the folding arm 90 acts via the link 92 on the folding arm
91, which, as a result, is caused to turn in the same direction as
folding arm 90. Since the bearing point 117 of link 92 in the
folding arm 91 is very close to the centre of rotation of folding
arm 91, the speed of rotation of folding arm 91 is considerably
greater than the speed of rotation of folding arm 90, so that the
folding arm 91 moves towards and approaches folding arm 90.
Since the base-forming sections 35 of the package blank 4 have been
folded as previously described with a view to breaking the crease
lines, the section (106 in FIG. 9) which impinches on edge 118 of
the folding arm 90 is folded inward over the aperture of package
blank 4 while at the same time the adjacent triangular sections and
fold-back sections are folded inward over the base aperture of
package blank 4 in the manner of a bellows.
In order to simplify the folding process, the rear one of the
rectangular sections (105 in FIG. 9) viewed in the direction of
movement is acted upon, as shown in FIGS. 6b and 7c, by the
striking edge 94 of folding arm 91, which depresses the rear
rectangular section 105 at the same time as the front rectangular
section 106 slides under edge 118 of the folding arm 90.
When the base-forming sections 35 are folded inward as shown e.g.,
in FIG. 6b, the stud 5 is moved under the pressure device 10 shown
in FIG. 7a, which is pressed against the upper face of stud 5 with
great force when the stud 5 is positioned below the pressure
device, whereby the base-forming sections 35 which have been
previously heated and folded towards one another are connected with
one another and cooled to such an extent that the seal which has
been obtained is mechanically durable.
Since during indexing the stud wheel 5 moves relatively quickly, it
is important for the masses of the folding arms to be kept as small
as possible, since otherwise the energy required for rapid
displacement of the folding arm 90 becomes so great that the front
edge of the package blank is deformed. The mass of the folding arms
may be reduced, e.g., by providing recessed holes in the folding
arms or by manufacturing the latter from a light material such as
e.g., aluminum or plastic.
D. TOP SEALING JAWS
When the containers 33 provided with a base are filled with the
intended charge, certain sealing sections 112 (FIG. 9) are
selectively heated whereupon the top-forming sections of the
containers are folded together and the sealing sections are brought
together and compressed between sealing jaws which, on the one
hand, exert a high pressure on the sealing sections and, on the
other hand, cool them so as to produce a durable and strong
seal.
It is known to actuate sealing pressure jaws by means of pneumatic
cylinders or similar devices, and these sealing jaws as such work
well within reasonable limits of efficiency and safety, but they
may occasionally disadvantageous owing to the fact that they
require a relatively large space. E.g., with packaging machines of
the type here considered which have twin-conveyor tracks 13, one
endeavours to locate the tracks 13 as close to one another as
possible so that the machine will not be too wide. A further reason
why one wishes to locate the conveyor tracks 13 as close to one
another as possible consists in that the processing stations along
the conveyor tracks 13, i.e., the folding station, the filling
station and the heating station, shall be capable of being equipped
with working devices driven by means of drives which need not be
duplicated at each station. The folding station, for instance,
comprises two folding devices 25 at each conveyor track 13, i.e.,
altogether four folding devices, and these four folding devices 25
can be driven by means of a common drive rod 14 controlled by a cam
disc 31. In the same way, the pumps of the filling system, which
serve four filling nozzles 16, can be driven by a single drive, and
the drive rods of the top heaters 17 are also driven by one and the
same drive.
The system shown in FIG.8 for closing and sealing the tops of the
filled packaging containers 33 comprises four pairs of pressure
jaws 126, 127 for each conveyor track 13, i.e., altogether eight
pairs of pressure jaws, all of which can be operated synchronously
by means of a single actuator. The closing system in accordance
with the invention is characterised in that it comprises two pairs
of pressure jaws, each with one movable jaw 127 and fixed pressure
jaw 126, the said pairs of pressure jaws being so arranged as to
work synchronously, in that the movable pressure jaws of each pair
of pressure jaws are connected with one another by means of link
arms 121 which are rotatably located in either of the movable
pressure jaws, and by a common, mainly horizontal shaft 122, which
is so arranged as to be capable of movement to a first and a second
position in the vertial plane, whereby the pairs of pressure jaws
are closed when the said shaft is in its first, upper position, and
the pressure jaws are open when the said shaft is in its lower,
second position.
The sealing system in accordance with the invention will be
described below in greater detail with reference to FIG. 8, which
shows the two conveyor tracks 13 and the filled containers 33
located within the retaining devices in the conveyor tracks. The
sealing system is fixed in a frame structure consisting of the
members 124 and 131 which are firmly joined to the machine base.
The fixed sealing jaws 126 are installed in the members 131 with
the aid of compression springs 128, the spring force of which can
be regulated by adjusting the nuts 132.
The fixed sealing jaws 126 are also suspended from the members 131
by means of links 133, which are joined, on the one hand, with the
fixed jaws 126 and, on the other hand, with the mountings 135 which
are firmly joined to the members 131. The movable sealing jaws 127
are suspended in links 123 which are arranged in pairs and capable
of being swivelled, in such a way that the sealing jaws 127 are
always horizontally orientated. The links 123 are not only attached
to the movable jaws but also to the transverse members 124 of the
frame structure. The four inner links 123, which are capable of
being swivelled are connected with one another in pairs by means of
a shaft 136, which, on the one hand, is rotatably rotated in the
movable jaws 127 and, on the other hand, in the link arms 121. The
link arms 121 are, in addition, rotatably joined by a shaft 122 at
their other end, the said shaft passing through all the link arms
121. The shaft 122 is subject to a tension spring 130 which tends
to move the shaft 122 downward, and the shaft 122 is, in addition,
connected with an actuating rod 120, which is actuated with the aid
of a cam disc 22.
The sealing jaws 126 and 127 are cooled with the aid of coolant
which is supplied through lines 125, and since the sealing jaws are
movable, it is advisable to make use of flexible hoses or pipe
connections, at least in the case of the coolant lines which
connect the sealing jaws with one another.
The sealing operation is effected by moving the filled containers
33 forward in stages by two retaining device divisions for each
indexing motion, and by guiding the containers 33 between the guide
rails 114, after heating their top sealing section, whereby the
said guide rails combine the top forming sections in such a way
that the sealing sections rest against one another. When the
containers 33 are centrally between the sealing jaws, the actuating
rod 120 is raised by means of the cam disc 22 not shown in FIG. 8,
whereby shaft 122 is also raised in opposition to the spring force
exerted by the tension spring 130. When the shaft 122 is raised
with the aid of actuating rod 120, the link arms 121 are angularly
displaced so that they assume a more horizontal position as a
result of which the links 123 attached to the members 124 are swung
to the side and consequently press the movable sealing jaws 127
against the fixed sealing jaws 126, whereby the sealing sections of
the containers 33 which are between the sealing jaws 126 and 127
are compresssed at high pressure and simultaneously cooled so that
a tight and permanent seal is achieved.
Since it is possible for the thickness of the packaging material to
vary somewhat, e.g., with different package sizes, it has been
found advantageous to make the fixed sealing jaws 126 slightly
resilient, since the cam control system has no natural flexibility.
It is also possible, by making the fixed sealing jaws 126
resilient, to bring about a nearly constant pressure which can be
adjusted by regulating the spring force of the springs 128, which
can be adjusted with the aid of nuts 132. If the fixed sealing jaws
are resilient, this of course gives rise to a certain lateral
displacement of the upper sealing fins of containers 33, but since
the resilience is very small, i.e., of the order of magnitude of
one-half mm, this does not result in any disavantage. For
controlling the fixed sealing jaws 126 they have been suspended in
links 133.
As previously mentioned, each conveyor track 13 is provided with
four pairs of sealing jaws, so that the containers 33 are exposed
to two consecutive compressing operations in order to ensure
adequate compression and cooling of the top seal, and the reason
for treating the filled containers 33 in this manner by two
consecutive operations is that the available time between two
consecutive indexing operations is not sufficient to achieve a seal
of the required strength.
* * * * *