Note: Descriptions are shown in the official language in which they were submitted.
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Process and Device for Producing a Flowable Product Package
Via a Shell
The invention relates to a method and a device for manufacturing a half-shell
5 from thermoformable plastics, in which at least one plate-shaped section, to
be worked, of the plastics material is intermittently transported downwards on
a vertical web through at least two heating stages, arranged one behind the
other in the direction of movement, to a deep drawing station, and is
subsequently deep-drawn.
A method for manufacturing a package for flowable media by means of deep
drawing of a half-shell with the features described above is known, in which
a blank rmade from the plastics described, in the form of a plate, is supplied
for the processing stages of the method and of the manufacturing device.
15 The plastics blanks are heated in two stages by means of contact heating
with heating blocks, and then deep-drawn by the lowest heating block directly
in the deep-drawing mould, forming a half-shell with a frame-shaped strip.
To form a package, two half-shells of this type are folded together along their
20 frame-shaped strips, which each lie in one plane, and welded together by the
action of heat.
Particularly advantageous with respect to the known device and also the
known manufacturing method is the fact that the whole blank is formed into
25 a half-shell or a group of half-shells without waste, as the whole of the blank
is brought to the desired temperature for thermoforming by the direct contact
heating with heating blocks and is then deep-drawn.
For fast and intensive heating of the plastics blanks, they are picked up by
30 vacuum by one heating block, and heated during standstill and movement
thereof, then transferred to the next heating block, heated again, passed back
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to a further heating block, and so on, whereby the slowly heating plastics
blank is transported by tools moving backwards and forwards, for example
vertically from above to below (with intermediate changing over to short
horizontal webs).
Under certain conditions, it has been shown to be disadvantageous that the
removal of a heated plastics blank from a heating block is particularly delicateand problematic in the area of the top edge, and particularly the top corners.
It has been established that even before final removal of a blank heated to
10 a relatively high temperature, its transfer is imprecise, wherein the formation
of folds or even downward folding over of the upper area of the heated blank
can occur. Because of this, the transporting of a plate-shaped blank is
clearly problematic. By means of the vertical movement of the blank made
from heated, and therefore already softened plastics, which is in the vertical
15 plane, there is often a tendenc,! in the upper area of the blank for one or
other of the corners or the whol ~ top horizontal edge to remain attached or
to become prematurely detache~5 and roll up. ~Ithough the failure rate is only
10-3, with the high capacity pro~esses of modern packaging machines, this
20 is an unacceptable rate of failure.
The object of the invention is therefore to avoid the uncertainties described
above in relation to the upper a,ea of the blank to be worked during package
manufacturing, and in particular lO improve the known method and the known
25 device so that the heating of th -~ plastics material prior to deep-drawing can
be done more easily and reliabiy from a technical point of view.
According to the invention, this object is solved with respect to the method
with the features of the type de: cribed in the introduction in that the plastics
30 material is supplied in the forn-1 of a continuous web from above the first
heating stage, with heating of t ;e web sections during movement, vertically
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downwards to the deep-drawing station, at the top end of which the
frontmost, lowest plate-shaped section is separated from the plastics web and
deep-drawn. The particular advantage of this method is that the whole
section to be heated of the web section, from which the half-shell will later be5 moulded and the half-package manufactured, is held in the desired position
in a stable and precise manner by its top horizontal edge by the web itself.
The individual section of the plastics web to be worked is still integral with the
plastics web until shortly before the deep-drawing procedure, so that
undesired detachment of corners or of a whole horizontal edge at the vertical
10 upper end of a heating area is eliminated. The upper edges of the web
section are held by the web itself, as the web sections are not yet separated.
This status extends from the vertical uppermost receiving position where the
plastics web is supplied, to the separating area between the block of the
deep-drawing tool and the heating block currently located above it.
It has been shown that with the implementation of this method and also
during the operation of the device still to be described hereinafter, a free topedge of a web section does not exist in the heating area, so it cannot topple
over or hang down. Instead, a vertical edge of this type is held by the web
20 located above it, to which the section is still attached. Separation of the
plastics web section to be deep-drawn takes place only in the bottom area,
over the deep-drawing block.
By means of these measures, the entire manipulation of the web section to
25 be deep-drawn is simplified. There is no longer any need for blanks
separated beforehand to be taken hold of, taken to other positions, placed on
heating blocks, or manipulated in other ways. These movements, and the
difficulties associated with them are eliminated by the measures according
to the invention.
It is also advantageous according to the invention when the separation of the
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lowest plate-shaped section from the plastics web takes place in a heated,
plastic state by mechanical pinching-off during the deep-drawing. A high
degree of cutting force and expensive cutting tools are unnecessary. Instead,
the separation takes place according to the invention only after heating of the
5 plastics web to the designated highest temperature at which the lowest and
frontmost section of the plastics web has a doughy consistency, with the
result that a blade can press to the side or pinch the plastics and
nevertheless a precise separation along a desired line takes place.
10 With an advantageous further embodiment of the invention, two continuous
plastics webs at a distance apart are simultaneously moved vertically
downwards, so that their planar surfaces lie parallel and facing one another,
and after the deep-drawing procedure, the deep-drawn half-shells are welded
together along their edges to form the volume of a package for flowable
15 media. In this way a package for flowable media is produced by means of
a half-shell. Clearly, several pairs of half-shells can be deep-drawn
simultaneously, and thereby several packages for flowable media
manufactured simultaneously, preferably with a single lifting. In this manner,
for example, a first plate-shaped section to be worked, of the plastics web,
20 and a further plate-shaped section arranged at a distance from the first, aretransported intermittently downwards as a pair, with the same movement, on
a vertical web through the two heating stages.
In this way, although the plate-shaped sections are heated to the desired
25 temperature during backwards and forwards translatory movements, these
sections are still located integrally on the plastics web and are therefore heldprecisely and cleanly in the desired position. Only when the deep-drawing
procedure takes place does the separation of the plate-shaped section occur,
wherein although external edges Iying in a plane are still warm and capable
30 of adhesion, the half-shell is formed in the central area. Clearly, in a further
step the deep-drawn half-shells are then welded together along their edges,
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whereby a package for flowable media, possibly open on one side, or two
packages for flowable media, not yet open to the exterior, are formed as a
palr.
5 A device with which at least one plate-shaped section of plastics material to
be worked is transported intermittently on a vertical web through at least two
heating stages arranged one behind the other in the direction of
displacement, and is subsequently deep-drawn, serves to implement the
method described above. In order to solve the object set out above, with
10 respect to the device the invention provides that above the uppermost
heating stage, a guide roller with preceding conveying apparatuses for a
supplied continuous plastics web is provided, and that a blade extending
across the width of the plastics web is movably attached at the level of the
top edge of the deep-drawing tool.
The man skilled in the art could have provided complicated apparatuses to
solve the object set out, in order to hold, grip and support the currently
vertical, uppermost, horizontally extending edge of a separated plastics
section. The cost of such means would, however, be prohibitive from both
20 the technical and economic point of view. Conversely, the proposal
according to the invention is unexpectedly simple, wherein the plastics web
from which the plate-shaped sections to be worked are to be formed is
divided into the individual sections later on, such that the heating procedure
with the substantial transferring movements from one heating block to the
25 other still takes place directly dependent upon the continuous plastics web.
It has further been shown unexpectedly that in spite of this technique, there
need be no more waste, nor is there any more, than with the known, more
expensive machines in which the separated plate-shaped blanks are
transported.
The plastics web is supplied by means of known conveying apparatuses to
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a guide roller, which according to the teaching of the invention is arranged
above the uppermost heating stage. The continuous plastics web can, in this
way, intermittently be guided and held precisely, in one piece, through the
heating stages until the deep-drawing station is reached. By means of the
5 arrangement of the moveable blade in the area of the top edge of the deep-
drawing tool, the deep-drawing procedure can be undertaken during the
separation of the blank from the web, preferably also during the placing of the
external edges of the deep-drawing tool on the heating counter plates
(warming blocks). The are no problems with transfer at this point, as the
10 deep-drawing technique is technically advanced and uses, at least on the
deep-drawing mould side, a cooled tool, so that the problems described in
the introduction can no longer occur at this point.
It is furthermore advantageous according to the invention, when two supply
15 rollers are arranged at the level below the deep-drawing tool and laterally, at
a horizontal distance from a vertical plane of symmetry as well as from one
another, each for one plastics web which is moveable in each case by means
of conveying apparatuses to a guide roller arranged adjacent to the plane of
symmetry, and that two moveable long blades arranged at a distance apart
20 from one another are provided, which are arranged parallel to one another
and to the plane of symmetry.
If a stationary plane of symmetry is conceived of, then two plastics webs can
move vertically downwards at a distance from this plane of symmetry so that
25 in the upper area the heating zones are located, and in the lower area the
deep-drawing stations. With this, the planar surfaces of the plastics web are
located parallel to each other and face each other. On each side of the
plane of symmetry, heating of a first section of the plastics web takes place,
in pairs at the same level, and the subsequent deep-drawing also takes place
30 on both sides of the plane of symmetry such that subsequently two deep-
drawn half-shells are located opposite one another. The arrangement of the
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deep-drawing tools is advantageously provided so that the insides of the half-
shells are opposite one another so that then the two half-shells can be placed
directly together along their edges and welded together. If a pair of half-
shells is produced in this way, or even several pairs of half-shells, either a
5 pair of packages or even several pairs of packages can be produced at the
same time, with one processing procedure by the device.
The plate-shaped sections of the plastics web are heated by bodily contact
with the heated blocks, wherein the heating to the required temperature for
10 deep-drawing is best divided between two stages, as then the manufacturing
process can easily be adjusted for a continuous process. While the plate-
shaped areas are being separated from the web in the manner of blanks,
they have the pre-determined softness for deep-drawing and only need to be
held in the area of the external frame-shaped strip between heating blocks
15 and an advancing deep-drawing tool in order to mould the central area in the
deep-drawing tool by means of a vacuum. If two oppositely located mould
halves are allowed to move onto one another as quickly as possible after
deep-drawing, the two deep-drawn half-shells can be pressed together and
welded together along the frame-shaped strips or edges, possibly even
20 making use of the remaining heat.
The manufacturing method for packages can be significantly accelerated by
means of simultaneous moulding of several packages. It is advantageous
when, with the method according to the invention and the device described
25 herein, the heating of the plate-shaped sections of the plastics web is to
1 60C to approximately 200C, preferably 1 70C to 1 80C, and when
approximately three seconds, preferably two to three seconds, elapse in each
heating stage. In this way the web sections are brought to the correct degree
of softness, in particular with two or three stage heating of the substantially
30 planar web sections. In this way in a very short time the frame-like surface
of the mould block of the deep-drawing tool can grip and hold the half-shell
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by the frame-shaped strips or by its edge, and press it against the
corresponding frame-shaped strips of the opposite piece of a pair, using
either the remaining heat or using further heating, so that one whole package
is made from the two half-shells.
During processing of the plate-shaped web section with the method according
to the invention, it is advantageous when pairs of plate-shaped sections are
conveyed by gravity, supported by certain drives, or by means of compressed
air/suction drives, through the individual stages of the method. In this case,
10 gravity facilitates transport in the perpendicular direction, wherein in the
device it is advantageous to have the possibility of switching from vacuum to
compressed air and vice versa.
According to the invention, it has been proven that it is advantageous to use
a 0.2 to 1.7 mm, preferably 0.4 to 1.0 mm thick plastics web for the plate-
shaped web sections, made from a preferably filled, deep-drawable
thermoplastic material for the manufacturing of the half-shells, that is to say
packages for flowable media. Cold-workable and hot-workable plastics
materials are known and they are all suitable for the manufacture of a
20 package according to the method described. Preferably, the plastics material
of the package is deep-drawable, in particular a thermoplastic material such
as, for example, polypropene. PVC can also serve, for example, as the
thermoplastic material, and polypropene is widely known in the industry as
polypropylene. When such a material is used, the package manufactured
25 with the method according to the invention is composed of perfectly re-
workable parts and materials (in contrast to composite materials). In a
preferred embodiment, the plastics material, for example the polypropene,
can also be filled, wherein chalk, mica, talcum, plaster or the like is
envisaged as the filler. In practice, degrees of filling of approximately 60%
30 have proved advantageous.
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g
Further advantages, features and possibilities for use of the present invention
will become apparent from the following description of preferred
embodiments, with reference to the attached drawings, which show in:
Figure 1 schematically and partly cut-away, a device for manufacturing
packages for flowable media, shown in perspective, wherein
numerous details are omitted,
Figure 2 schematically, the front view of the device when viewed in the
direction of the plane of symmetry and opposite the direction of
conveyance of the completed row of packages,
Figures 3a and 3b schematically detailed, the main working parts of the
device with advancing, external and deep-drawing tools, wherein
Figure 3a shows a first, and Figure 3b shows a second operational
state,
Figure 4 the side view of two packages joined head to head, which are
formed from two corresponding deep-drawn half-shells, when
viewed in the direction of the seam joined by welding, before the
complete bodies are separated to form the individual packages,
and
Figure 5 a view of the double package according to Figure 4, when this
double package is viewed from the side, for example from the right
in the direction of the plane of the paper in Figure 4 to the left,
vertically along the plane of the weld seam described.
Figure 1 shows the device for manufacturing the half-shells, with subsequent
apparatuses for manufacturing packages, with only a few important parts
inside a housing which is not shown in more detail. Electric drive motors,
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gears, shafts and the like are omitted. The configuration of the heating,
deep-drawing and welding apparatus is symmetrical with respect to the plane
of symmetry 37. This is vertically perpendicular in space, and is again
present in Figures 2 and 3. In the lower part of the machine a supply roller
5 39 is located at a distance to the side of the plane of symmetry on each side, from which the plastics material in the form of a continuous web 40 is
brought, via two first guide rollers 41, 42, forming a buffer loop, to a third
guide roller 43. The direction of conveyance of the plastics web is in all
cases shown by the arrow 44. Below the two guide rollers 43 there is located
10 at the top firstly the receiving position, with two unheated and thus relatively
cold plates, which are each fixed to the tool located underneath, as will be
explained with reference to Figures 3a and 3b. In the receiving position, the
cold web is taken hold of and drawn down by one section length. If the web
were already heated here, it would stretch. Consequently, the handling into
15 the receiving position is done by means of suction and frictional engagement
at room temperature. Below this there then follows the heating stage,
generally designated 45, which together with the deep-drawing station
arranged further below, generally designated 24, is configured symmetrically,
as is shown and explained in more detail in Figures 3a and 3b.
Figure 1 shows how the left-hand deep-drawing tool 16 is opened and how
on each side five pairs of half-shells, attached to each other, have been
produced. They appear prominent for reasons of better representation.
At the level of the top edge 46 of the deep-drawing tool 16, a blade 47
extends over a width B of the plastics web 40 which is moveable towards and
away from it along the plane of symmetry 37 in a horizontal direction (double
arrow 20) by means of drives and guides which are not shown.
After welding together of the half-shells, the volume of a package for flowable
media 48 is formed and a group of packages joined head to head is
1 1 2 1 7 ~ ~$4
produced, as shown at 49.
In a next station, not shown, this group of joined packages 49 is brought into
the horizontal position along the curved arrow 50, and conveyed slowly
5 vertically from below to above in a cooling station 51. From there, the
packages are separated in a separating apparatus, not shown, which is just
generally designated 52, so that packages upwardly open at the opening
device, Iying in a row on top of one another, are created. These are moved
from the horizontal into the vertical in the turning apparatus 43, until they are
10 laid down on a transport apparatus 54. From here on further processing
procedures take place in a known manner, such as, for example, die cutting
of corner pieces at the station 55, lifting, filling with contents and re-lowering
at the station 56, and closure of the opening device in the station generaliy
designated 57.
If the plane of symmetry 37 is viewed from the front, this appears in Figure
2 as a vertical line, which extends perpendicularly through the heating stage
45 and the deep-drawing tool 16 located beneath it, as far as through the row
of double packages 49 laid on the conveyor belt 27.
The apparatuses for heating and deep-drawing 45, 24 are mirror-symmetrical
with respect to the plane 37 and shown schematically in Figures 3a and 3b.
Only one half needs to be described by way of example, as the other half is
configured identically.
On the lifting device 38 shown in the top centre of Figure 2, the advancing
heating block, generally designated 5, is attached, which is consequently
movable in the direction of the double arrow 21 in a translatory manner,
upwards and downwards by half the amount of lift H.
In the schematic drawings according to Figures 3a and 3b, two half-shells 25,
5~
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open on one side, can be moulded in each side of the deep-drawing tool 16
below.
The advancing heating block, generally designated 5, is configured in each
5 half so that it stops in the middle of a heatable main carrier 6 and three main
suction plates, arranged one above the other. In this case there is specially
a cold upper main suction plate 7, with suction intakes 8, a central main
suction plate 7a and a lower main suction plate 7b. The main carrier 6
extends integrally over all three suction plates 7, 7a and 7b. The total
10 vertical length of the advancing heating block 5 is approximately 1 m.
The external heating blocks 14 forming the heating stage 45 are located
laterally offset. The direction of movement of these is perpendicular along
the plane of symmetry 37, according to the double arrow 20.
On the left side of the plane of symmetry 37, that is to say on the side facing
away from the advancing heating block 5, the external heating block 14 is
provided with an external car ier 10 extending over its whole height H, on
which, on the side facing the advancing heating block 5, there is fitted heat
20 insulation 11 and on this - again facing the block 5 - an external heating body
12, and further inside, facing the heating block 5, an external suction plate
13. In total, the external heating block 14 has, over its height H, two groups
of external suction plates 13, the surface of which in each case is the same
size as that of the main suction plates 7, 7a and 7b. On the upper external
25 suction plate 13, the unheated and therefore relatively cold external pressure
plates 30 are fixed, which when the external heatin~ block 14 moves
horizontally, is moved with it. The two unheated and therefore relatively cold
main suction plates 7 are similarly fitted on the upper main carrier 6. The
external suction plates and main suction plates are substantially the same
30 height and the same length compared to one another, and they can be laid
one on top of the other with light pressure, so that a good heat transfer to the
1 3
plastics web 40 Iying in between them is obtainable.
The movable deep-drawing tool 16 arranged separately from the suction
plates, is also moveable horizontally in the direction of the double arrow 20.
In operation, the device functions as follows:
The plastics web 40 is moved downwards vertically from above to below on
each side of the plane of symmetry 37 intermittently in the direction of the
10 arrow 21. It is integral as far as the level of the top edge 46 of the deep-
drawing tool 16 - or slightly beyond it - and is cut by pinching off at this level
by the blade 47, movable in the direction of the double arrow 20.
According to Figure 3a, the deep-drawing tool 16 is displaced to the left, so
15 that the whole advancing heating block 5 can be moved downwards by one
station. In this way the cold main suction plate 7 is opposite the cold externalpressure plate 30, which moves in the direction of the horizontal arrow 20 to
the cold main suction plate 7. The web section arranged in between is
pressed in this way against the internal cold main suction plate 7, and with
20 this its suction intakes 8 can become effective. Now the lower web section
described is held and moves during the next downward movement in the
direction of the vertical arrow 21 downwards by one stage, so that the
position in Figure 3b is reached.
25 In Figu!e 3b the cold external pressure plates 30 have no counterparts, whilethe cold main suction plate 7 is opposite to the suction intakes of the upper
external suction plate 13. In this way the main suction plate 7a is opposite
the lower external suction plate. Firstly, when moved down, the leading edge
of the plastics web 40, that is to say the web section now being considered,
30 was suctioned onto the cold main suction plate 7. At this point compressed
air is switched to, so that the web section is moved to the external suction
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plate 13, onto which the suction intakes, which are not shown, pull the web
section. This external suction plate 13 is a heating block, so that at this point
the first stage of heating begins. The respective external heating blocks 14
are then moved outwards horizontally in the direction of the arrow 20, and
5 while heating it, carry along the lower web section, which is still attached to
the plastics web 40. The upper main suction plate 7 is meanwhile free and
can be moved together with the whole advancing heating block 5 in an empty
state upwards into the position in Figure 3a. There, the next, still cold plate-shaped section of the plastics web 40 is suctioned on. As the central main
10 suction plate 7a is now opposite the upper external suction plate 13, the
transfer of the web section under consideration, which is already pre-heated,
to the central main suction plate 7a can be undertaken in the same way.
This is done by switching the suction intakes of the external suction plate 13
to compressed air and switching the suction intakes of the central main
15 suction plate 7a to suction mode.
After the external suction plates are conducted horizontally outwards, the
advancing heating block 5 can again move down to the position in Figure 3b.
Now the central main suction plate 7a is opposite the lower main suction
20 plate 13. Here, transfer of the leading plate-shaped section of the plastics
web 40 to the lower external suction plate 13 can take place. After
establishing the lateral distance apart, the advancing heating block 5 can
again go upwards by one stage to the position in Figure 3a.
25 After this, the lower main suction plate 7b is opposite the lower external
suction plate and can take the leading plate-shaped section of the plastics
web 40 for the last heating.
If after this the lateral distance apart between the main suction plate 7b and
30 the external suction plates 13 is produced again, and the advancing heating
block 5 has moved downwards to the position in Figure 3b, then the lower
1 5 ~ ~ 7 ~ ~ S 4
main suction plate 7b is opposite the deep-drawing tool 16.
The deep-drawing tool 16 can approach the lower main suction plate 7b and
seal the edge. When the air suction is switched on in the individual deep-
5 drawing tools 16, and deep-drawing begins, the blade 47 simultaneously cuts
the frontmost plate-shaped section from the remaining continuous plastics
web 40. The half-shell is meanwhile formed and the advancing heating block
5 is still located in its lower position, shown in Figure 3b.
10 If the advancing heating block 5 is moved upwards in the direction of the
arrow 21, two freshly deep-drawn half-shells (or half-shell groups) are
opposite one another, wherein the frontmost planar areas are their edges 6.
The deep-drawing tools are moved horizontally towards each other in the
direction of the arrow 20 and the edges pressed together. With this, the two
15 half-shells are united to form one package (or the groups of half-shells are
united to form groups of packages).
If Figures 4 and 5 are considered, then the packages, still fixed together head
to head, with side walls 1, base 2 and top wall 3 can be seen therein. A
20 seam 60, which is also called the weld seam, and surrounds the package,
lies in a plane with respect to the longitudinal central axis of the package 1.
It divides the package into two halves and passes through the base 2 along
an indentation 61, so that seen in total, the base 2 is substantially flat with
a planar external contour, without the protruding seam 60 getting in the way.
25 On the top 3, an externally protruding band 9, with an external thread 11 can be seen.
The seam 60 runs as far as the upper edge of the band 9, where the two
bands are still joined together, but narrows at this central connection point
30 towards the last part 13.
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The drawing in Figure 4 shows that the seam 60 is formed from two edge
flanges of the pair of moulded halves, as these edges or edge flanges are
welded together into the seam 60 described. The externally substantially
closed entirety of the two packages, here shown joined together head to
5 head by means of the bands 9, which are formed from a left-hand moulded
half-pair and a right-hand half-pair, can be seen. Separation takes place later
(see station 52 in Figure 1) along the line shown by the arrow 14 in Figure
4. By separation, the pairs of packages are separated from one another, so
that there are then two individual packages or two rows of packages arranged
10 one behind the other, as shown in Figure 1.
