U.S. patent application number 15/446660 was filed with the patent office on 2017-06-22 for method and apparatus for producing a plastic profile having a reinforcement.
This patent application is currently assigned to Thomas GmbH + Co. Technik + Innovation KG. The applicant listed for this patent is Thomas GmbH + Co. Technik + Innovation KG. Invention is credited to Klaus Jansen.
Application Number | 20170173851 15/446660 |
Document ID | / |
Family ID | 45872903 |
Filed Date | 2017-06-22 |
United States Patent
Application |
20170173851 |
Kind Code |
A1 |
Jansen; Klaus |
June 22, 2017 |
METHOD AND APPARATUS FOR PRODUCING A PLASTIC PROFILE HAVING A
REINFORCEMENT
Abstract
In the pultrusion of reinforced plastic profiles in strand form,
the strands of the reinforcement are brought together in a
positioning device and subsequently embedded in the plastic. The
pulling of the strands of the reinforcement through the positioning
device leads to an unwanted contraction and uncontrolled
positioning of the reinforcement in the plastic profile. The
invention envisages forming the positioning device by multiple
successive positioning means, of which at least some positioning
means can be periodically moved forward in the direction of
production and also moved back counter to the direction of
production. As a result, there is an alternating tensioning and
compression of individual regions of the reinforcement. This makes
exact positioning of the reinforcement in the plastic profile
possible and prevents contraction of the reinforcement.
Inventors: |
Jansen; Klaus; (Buxtehude,
DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Thomas GmbH + Co. Technik + Innovation KG |
Bremervorde |
|
DE |
|
|
Assignee: |
Thomas GmbH + Co. Technik +
Innovation KG
Bremervorde
DE
|
Family ID: |
45872903 |
Appl. No.: |
15/446660 |
Filed: |
March 1, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14005716 |
Jan 10, 2014 |
9630360 |
|
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PCT/EP2012/001159 |
Mar 15, 2012 |
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15446660 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B29C 70/521 20130101;
B29C 70/526 20130101; B29C 70/56 20130101; B29C 70/528 20130101;
B29C 70/543 20130101; B29C 70/541 20130101; B29C 70/523 20130101;
B29C 70/525 20130101; B29C 55/30 20130101 |
International
Class: |
B29C 55/30 20060101
B29C055/30; B29C 70/54 20060101 B29C070/54; B29C 70/52 20060101
B29C070/52 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 30, 2011 |
DE |
102011015607.0 |
Claims
1. An apparatus for producing a plastic profile (10, 33) having a
reinforcement (11), comprising: a closed mold (23, 32), completely
surrounding the plastic profile (10, 33); at least one positioning
device (14), for the reinforcement (11) of the plastic profile (10,
33), arranged upstream of the mold (23, 32) in the direction of
production (13) of the plastic profile (10, 33) the positioning
device (14) having multiple successive positioning means (15, 16,
17, 18); and at least one of the positioning means (15, 16, 17, 18)
being movable back and forth in relation to at least one other
positioning means (15, 16, 17, 18).
2. The apparatus as claimed in claim 1, wherein each positioning
means (15, 16, 17, 18) is formed like an orifice plate and/or each
positioning means (15, 16, 17, 18) has a passage (28, 29, 30, 31)
for the reinforcement (11) and the passages (28, 29, 30, 31) in the
positioning means (15, 16, 17, 18) following one another in the
direction of production (13) become smaller in the direction of
production (13).
3. The apparatus as claimed in claim 1, wherein the positioning
means (15, 16, 17, 18) that is movable back and forth is
periodically moved independently of the other positioning means
(15, 16, 17, 18).
4. The apparatus as claimed in claim 1, further comprising at least
one pulling device (24) that can be periodically moved back and
forth, wherein the at least one pulling device (24) follows the
mold (23, 32) in the direction of production (13).
5. The apparatus as claimed in claim 3, wherein the positioning
means (15, 16, 17, 18) that is movable back and forth is
periodically moved independently of the other positioning means
(15, 16, 17, 18) by a drive or actuator of its own.
6. The apparatus as claimed in claim 4, wherein the pulling device
(24) has a cooling arrangement and/or consists of multiple gripper
parts that can be moved together and apart and in the
pressed-together state completely grip around the plastic profile
(10, 33) to be produced.
7. A method for producing a plastic profile (10, 33) having a
reinforcement (11), comprising: passing the reinforcement (11) with
plastic (12) embedding the reinforcement through a mold (23, 32) in
the direction of production (13); forming the mold (32) with
multiple mold portions (34) following one another in the direction
of production (13) and respectively having a molding passage (35)
corresponding to the cross section of the plastic profile (10, 33)
to be produced; and displacing the mold portions (34) such that the
longitudinal directions (36) of the molding passages (35) lie on a
longitudinal center axis of the plastic profile (10) to be produced
and/or run tangentially with respect to the longitudinal center
axis (37) of the plastic profile (33) to be produced to achieve a
desired shape of the plastic profile (10, 33).
8. The method as claimed in claim 7, wherein the mold portions (34)
are displaced in such a way that the inclinations of the
longitudinal directions (36) of the molding passages (35)
change.
9. The method as claimed in claim 7, wherein the mold portions (34)
are displaced in such a way that, in the case of plate-like mold
portions (34), points of the molding passages (35) that lie in the
center of the plate lie on the longitudinal center axis (37) of
each plastic profile (10, 33) to be produced.
10. The method as claimed in claim 8, wherein the mold portions
(34) are displaced in such a way that, in the case of plate-like
mold portions (34), points of the molding passages (35) that lie in
the center of the plate lie on the longitudinal center axis (37) of
each plastic profile (10, 33) to be produced.
11. An apparatus for producing a plastic profile (10, 33) having a
reinforcement (11), comprising a mold (32) that brings the plastic
profile (10, 33) with the reinforcement (11) lying therein into the
desired form, wherein the mold (32) is formed by multiple mold
portions (34) following one another in a direction of production
(13) and having molding passages (35) corresponding to the cross
section of the plastic profile (10, 33) to be produced, and the
size of each molding passage (35) changes in the longitudinal
direction (36) of the same or in the direction of production (13)
of the plastic profile (10, 33).
12. The apparatus as claimed in claim 11, wherein the mold portions
(34) are formed as mold plates, the molding passages (35) that
extend transversely through the mold plates being smallest
approximately in the center of the respective mold plate and
increasing in size increasingly toward opposing main surfaces of
the molding plates.
13. The apparatus as claimed in claim 11, wherein the mold portions
(34) can be tilted, by the longitudinal direction (36) of the
molding passage (35) in the respective mold portion (34), namely
the respective mold plate.
14. The apparatus as claimed in claim 13, wherein the respective
mold plate is variable in inclination.
Description
STATEMENT OF RELATED APPLICATIONS
[0001] This patent application is a division and claims the benefit
of U.S. patent application Ser. No. 14/005,716 having a filing date
of 10 Jan. 2014, now US Patent Publication No. 20140117581 having a
publication date of 1 May 2014, pending and allowed, which is the
US National Phase under 35 USC 371 of International Application No.
PCT/EP2012/001159 having an international filing date of 15 Mar.
2012, which claims priority on and the benefit of German Patent
Application No. 102011015607.0 having a filing date of 30 Mar.
2011.
BACKGROUND OF THE INVENTION
[0002] Technical Field
[0003] The invention relates to a method for producing a plastic
profile having a reinforcement, the reinforcement being passed
uninterruptedly through a positioning device and a mold then
following in the direction of production, and the plastic profile
with the reinforcement embedded therein being pulled by a pulling
device through the positioning device and the mold in the direction
of production, or a method for producing a plastic profile having a
reinforcement, the reinforcement with the plastic embedding the
latter being passed through a mold in the direction of production.
Furthermore, the invention relates to an apparatus for producing a
plastic profile having a reinforcement, with a closed mold,
completely surrounding the plastic profile, and at least one
positioning device, for the reinforcement of the plastic profile
arranged upstream of the mold in the direction of production of the
plastic profile, or an apparatus for producing a plastic profile
having a reinforcement, with a mold that brings the plastic profile
with the reinforcement lying therein into the desired form.
[0004] Prior Art
[0005] Reinforced plastic profiles have an uninterrupted
reinforcement of, in particular, fibers, woven, braided and/or
knitted fabrics, which are embedded in the plastic as a matrix. The
plastic may be a thermoset, or else a thermoplastic. Reinforced
plastic profiles are mostly produced uninterruptedly, in particular
continuously, in a strand. This takes place with preference by the
extrusion or pultrusion process. In this case, the reinforcement is
pulled through a positioning device and subsequently passed through
a mold. In the mold, the reinforcement and the plastic are brought
into the desired profile. The plastic profile leaving the mold is
pulled off by a pulling device following the mold in the direction
of production. In this case, the reinforcement is pulled through
the positioning device and the plastic with the reinforcement
embedded therein is pulled through the mold.
[0006] In the case of the previously known production of reinforced
plastic profiles, the positionally exact introduction of a
non-unidirectional reinforcement into the plastic is particularly
problematical. The tensile forces exerted on the reinforcement by
the pulling device lead to distortions of the non-unidirectional
reinforcement, such as in particular woven, nonwoven and braided
fabrics. This has the effect that the reinforcement does not have
the desired positioning in the plastic profile to be produced. This
applies in particular in the case of a reinforcement with a large
fiber volume.
[0007] Furthermore, previously reinforced plastic profiles with a
non-straight, in particular arcuate, shape are only possible with
molds that are specifically adapted to the shape of the reinforced
plastic profile to be produced.
BRIEF SUMMARY OF THE INVENTION
[0008] The invention is thus based on the object of providing a
method and an apparatus whereby the reinforcement can be embedded
exactly in the plastic profile to be produced and/or reinforced
plastic profiles with various shapes can be produced with a
universal mold.
[0009] A method for achieving at least a partial aspect of the
object is a method for producing a plastic profile having a
reinforcement, the reinforcement being passed uninterruptedly
through a positioning device and a mold then following in the
direction of production, and the plastic profile with the
reinforcement embedded therein being pulled by a pulling device
through the positioning device and the mold in the direction of
production, characterized in that the reinforcement is pulled
through a positioning device with at least two successive, separate
positioning means and at least one positioning means is thereby
moved in relation to at least one other. Accordingly, the
reinforcement is pulled through at least two separate positioning
means arranged following one another upstream of the mold, seen in
the direction of production, at least one positioning means being
relatively movable with respect to at least one other positioning
means. Preferably, all of the positioning means that are separate
from one another are movable in relation to one another. The
relative mobility of at least one positioning means has the effect
that preferably the reinforcement is compressed phase by phase
and/or portion by portion as it is pulled through the positioning
means, and is consequently not constantly exposed to tensile
loading. This results in a snaking movement of the reinforcement
through the positioning means, which has the consequence of
momentarily relieving the reinforcement of loading region by
region. Deformations or distortions of the reinforcement are
thereby avoided, or at least reduced, which has the consequence of
a controlled introduction of the reinforcement into the plastic. In
this way, a reinforced plastic profile with a reinforcement
distributed exactly over the cross section and positioned exactly
in the cross section can be provided.
[0010] It is envisaged with preference to change periodically the
distance between at least two positioning means following one
another in the direction of production. In particular, this can
take place by the at least one positioning means being movable back
and forth alternately in the direction of production and counter to
the direction of production in certain time intervals. As a result,
the tensile loading of the reinforcement is lifted for a time
alternately on opposite sides of the periodically moved positioning
means. There is preferably even a brief compression of the
reinforcement, pressed on one side and then on the other side of
the periodically moved positioning means. As a result, distortions
of the reinforcement, in particular transversely with respect to
the direction of production of the plastic profile, are avoided or
reduced. It is particularly advantageous if all of the positioning
means are moved back and forth periodically at regular time
intervals, preferably in a phase-offset manner. Then, various
portions of the reinforcement are alternately at least relieved,
preferably even for a short time compressed, in the region of the
positioning means.
[0011] In the case of a preferred refinement of the method, it is
envisaged to keep the reinforcement taut. This can take place by
securely holding the reinforcement upstream of the first
positioning means, for example by retarded unwinding of the
reinforcement from a supply roll and by securely holding the
produced reinforced plastic profile by the pulling device. Keeping
the reinforcements taut achieves the effect that, when at least one
positioning means is moved back counter to the direction of
production, the reinforcement or else the entire plastic profile is
not pulled back through the mold or pulling device counter to the
direction of production. Furthermore, keeping the reinforcement
taut has the effect that, when at least one positioning means is
periodically moved back counter to the direction of production, the
tensile stress in the portion of the reinforcement lying upstream
of the positioning means that is moving back can be reduced, or
possibly the reinforcement can be slightly compressed.
[0012] According to another advantageous refinement of the method,
the reinforced strand of plastic is cooled in the pulling device.
This also allows plastic profiles reinforced by the method to be
produced from a thermoplastic material, because then the not yet
completely cured plastic profile can leave the mold without the
risk of the lateral surface of the plastic profile sticking to the
molding surfaces of the mold.
[0013] It is particularly advantageous to press the reinforced
plastic profile leaving the mold radially together in the pulling
device. The pulling device may then serve for the final forming of
the plastic profile, this final forming, or else calibration, of
the plastic profile preferably taking place during the cooling of
the same, and, as a result, the lateral surface of the plastic
profile not being able to stick to the surfaces of the pulling
device that come into contact with it.
[0014] In particular, the pulling device may be formed or developed
such that it can be released from the circumference of the
finished, in particular cooled, plastic profile. For example, this
can take place by a multipart form of the pulling device, the
individual parts of the pulling device being able to move apart,
and thus demold the finished plastic profile in a practical manner.
Conversely, when the individual parts of the pulling device are
moved together, the plastic profile can be pressed, and the
intended cross section can thereby be obtained exactly. Thus, a
calibration of the plastic profile as it were takes place during
the pressing of the plastic profile in the pulling device, to be
precise preferably before the complete curing of the plastic
profile.
[0015] According to an advantageous development of the method, it
is envisaged not only to move at least one positioning means but
also the mold, an impregnating unit and/or the pulling device
periodically back and forth. In this case, the mold may be of one
part, but may also be divided into a heating device, a gel zone
region and a final reaction region.
[0016] Preferably, the periodic movement back and forth of the at
least one positioning means, of the mold and/or of the pulling
device takes place in a phase-offset or phase-shifted manner, so
that the tensile loading on the reinforcement is not lifted
uninterruptedly, but instead it is always the case that only
certain portions of the reinforcement are relieved of loading, or
even compressed, at different times one after the other or else
partially at overlapping times. As a result, when the forces are
applied to the reinforcement in the direction of production, and
possibly partially also counter to the direction of production,
when the plastic profile is being produced, there is a periodic
change of load on different successive regions of the reinforcement
between the pulling device and the first positioning means. These
changes of load are comparable to a snaking movement.
[0017] An apparatus for achieving at least a partial aspect of the
object mentioned at the beginning is an apparatus for producing a
plastic profile having a reinforcement, with a closed mold,
completely surrounding the plastic profile, and at least one
positioning device, for the reinforcement of the plastic profile,
arranged upstream of the mold in the direction of production of the
plastic profile, characterized in that the positioning device has
multiple successive positioning means, at least one positioning
means being movable back and forth in relation to at least one
other positioning means. Accordingly, multiple successive
positioning means are provided and at least one positioning means
is movable in relation to the at least one other positioning means.
If the movable positioning means is momentarily moved back counter
to the direction of production on the reinforcement, it "swallows
up" as it were a portion of the reinforcement, whereby the tensile
loading of this region of the reinforcement is momentarily lifted,
or there is even a brief portion-by-portion compression of the
reinforcement. Thus, according to the invention, a deformation, in
particular contraction, of the reinforcement is counteracted or a
contraction of the reinforcement that has possibly occurred is
reversed.
[0018] In the case of a preferred form of the apparatus, each
positioning means is formed like an orifice plate. Alternatively or
additionally, it is provided that each positioning means has a
passage for the reinforcement and/or the size of the passages of
the successive positioning means decreases in the direction of
production. The orifice-plate-like positioning means leads to a
bundling of the individual components of the reinforcement, for
example multiple strands running through. The alternative or
additional reduction in size of the passages of the successive
positioning means has the effect that the bundling takes place
stage by stage, by the reinforcement being reduced increasingly in
cross section from one positioning means to the other. The
increasingly smaller passages of the successive positioning means
cause a gradual, positionally exact bundling of the individual
components of the reinforcement, whereby a uniform distribution of
force is produced in the reinforcement during the production of the
plastic profile.
[0019] An advantageous refinement of the apparatus provides that
each positioning means that can be moved back and forth is
periodically movable independently of the other positioning means.
This movement of the respective positioning means may be performed
by a drive or an actuator, it being preferred for each movable
positioning means or groups of multiple positioning means to be
assigned a drive or actuator of its or their own. The drives or
actuators allow an individual movement of the positioning means
along the direction of production of the reinforced plastic
profile. In particular, they allow an independent or specifically
coordinated sequence of the movements of the positioning means if
multiple movable positioning means are provided.
[0020] It is also provided with preference that at least one
pulling device that can be periodically moved back and forth
follows the mold in the direction of production, the pulling device
being provided in particular with a cooling arrangement and/or
consisting of multiple gripper parts that can be moved together and
apart and in the moved-together state completely grip around,
preferably press together, the plastic profile to be produced. The
pulling device thus has multiple functions. It not only serves for
the discontinuous advancement of the reinforced plastic profile in
the direction of production, but also for the cooling and/or
pressing together of the plastic profile, whereby the latter is
calibrated. An apparatus with such a pulling device is also
suitable for producing the reinforced plastic profile from a
thermoplastic material.
[0021] A further method for achieving at least a partial aspect of
the object, which may also be a preferred development of the
previously described method, is a method for producing a plastic
profile having a reinforcement, the reinforcement with the plastic
embedding the latter being passed through a mold in the direction
of production, characterized in that the mold is formed by multiple
mold portions following one another in the direction of production
and respectively having a molding passage corresponding to the
cross section of the plastic profile to be produced, the mold
portions being displaced such that the longitudinal directions of
the molding passages lie on the longitudinal center axis of the
plastic profile to be produced and/or run tangentially with respect
to the longitudinal center axis of the plastic profile to be
produced to achieve a desired shape of the plastic profile.
According to this, the mold is formed by multiple mold portions
following one another in the direction of production, each mold
portion having a molding passage corresponding to the cross section
of the plastic profile to be produced. It is also envisaged to
displace the mold portions as and when required such that
longitudinal center axes or longitudinal directions of the molding
passages in the mold portions lie on the longitudinal center axis
of the plastic profile respectively to be produced or optionally
run tangentially thereto. In this way it is possible with one and
the same mold to produce plastic profiles with different shapes, in
particular both straight and curved shapes.
[0022] Preferably, the molding portions are displaced in such a way
that the inclinations of the longitudinal directions of the shaping
passages change. Different inclinations of the longitudinal center
axes of the molding passages of different mold portions allow a
plastic profile that is curved in any way desired to be produced.
The mold portions may however also be aligned such that the
longitudinal directions or longitudinal center axes of their
molding passages lie on an identical, straight line, in order to
produce straight plastic profiles.
[0023] A preferred development of the method envisages displacing
the mold portions in such a way that, in the case of plate-like
mold portions, points of the longitudinal center axes of the
molding passages that lie in the center of the plate lie on the
longitudinal center axis of the plastic profile to be produced.
Then, the straight or else non-straight shape of the plastic
profile is fixed in the direction of production by these points of
the longitudinal center axes of all the mold portions.
[0024] A further apparatus for achieving the object mentioned at
the beginning, which may also be a preferred development of the
previously described apparatus, is an apparatus for producing a
plastic profile having a reinforcement, with a mold that brings the
plastic profile with the reinforcement lying therein into the
desired form, characterized in that the mold is formed by multiple
mold portions following one another in the direction of production
and having molding passages corresponding to the cross section of
the plastic profile to be produced, and the size of each molding
passage changes in the longitudinal direction of the same or in the
direction of production of the plastic profile. In the case of this
apparatus, the mold is formed by multiple mold portions following
one another in the direction of production with molding passages
corresponding to the cross section of the plastic profile to be
produced, the size of the molding passage in each mold portion
changing in the direction of production. Preferably, as a result
the mold walls of the molding passages are convexly formed, so that
the molding passages of the mold portions have a constriction in a
plane running transversely with respect to the direction of
production or the longitudinal axis of the plastic profile. As a
result, the molding passage does not come into contact with the
plastic profile to be produced over its entire length, but only at
its narrowest point. As a result, a plastic profile can even be
produced with tilted mold portions, to be precise then with a shape
that is curved to a greater or lesser extent or is in some other
way not straight, in particular of any desired shape, in dependence
on the tilting of the mold portions.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] The inventions are explained in more detail below on the
basis of the drawing, in which:
[0026] FIG. 1 shows a schematic side view of an apparatus for
producing a reinforced plastic profile,
[0027] FIG. 2 shows a graphic representation of the sequence of
movements over time of individual components of the apparatus of
FIG. 1,
[0028] FIG. 3 shows a schematically represented section through a
mold for producing an arcuate plastic profile, and
[0029] FIG. 4 shows the mold of FIG. 3 in an arrangement for
producing a straight plastic profile.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0030] FIG. 1 shows the essential components of an apparatus for
producing a reinforced plastic profile. This apparatus is a
pultrusion apparatus for a plastic profile 10 with a reinforcement
11. The reinforcement 11 is completely embedded in a plastic 12,
which may be both a thermoset and a thermoplastic.
[0031] The reinforcement 11 may be formed by a multiplicity of
uninterrupted strands, but also a nonwoven, woven and/or knitted
fabric. The reinforcement 11 may also consist of combinations of
strands, nonwoven, knitted and/or woven fabrics. Preferably, the
reinforcement 11 is formed by high-strength synthetic, glass and/or
carbon fibers or strands.
[0032] The plastic profile 10 may have any desired cross sections.
In the longitudinal direction, which corresponds to the direction
of production 13 of the reinforced plastic profile 10, the plastic
profile 10 may either run in a straight line, as represented in
FIGS. 1 and 4, or else be arcuate, according to FIG. 3. In
addition, the plastic profile 10 may have any other desired shapes
in the longitudinal direction. The invention is therefore neither
restricted to the cross section nor to the shape of the plastic
profile 10. In particular, non-straight shapes of the plastic
profile 10 may be both confined to one plane (two-dimensional) or
else be three-dimensional.
[0033] The apparatus shown has multiple components following one
another at a distance in the direction of production 13. At the
beginning of the apparatus there is a positioning device 14 for the
reinforcement 11. According to the invention, the positioning
device 14 is formed by multiple positioning means following one
another at a distance in the direction of production 13. The
positioning device 14 shown is formed by four successive
positioning means 15, 16, 17 and 18. However, the invention is not
restricted to this. In the simplest case, the positioning device 14
need only have two positioning means, and it may also be formed by
more than four positioning means 15, 16, 17, 18.
[0034] The positioning device 14 is followed in the direction of
production 13 by an impregnating device 25, for feeding the liquid
plastic 12 to the reinforcement 11 bundled in the positioning
device 14, a heating device 19 with a cooled inlet 20 at the
beginning, a gel zone region 21 and a final reaction region 22. The
heating device 19 with the cooled inlet 20, the gel zone region 21
and the final reaction region 22 together form an annular, closed
mold 23, surrounding the plastic profile 10, of the apparatus, for
which purpose they may possibly be completely or partially combined
to form a single unit or possibly also multiple units.
[0035] At a distance downstream of the final reaction region 22 of
the mold 23, seen in the direction of production 13, there is a
pulling device 24, which pulls the plastic profile 10 through the
positioning device 14, the impregnating device 25 and the mold 23.
The pulling device 24 also serves for keeping the reinforcement 11
taut during the entire operation of producing the plastic profile
10, by the individual component parts, for example strands, of the
reinforcement 10 being subjected to a restraining force, acting
counter to the holding force of the pulling device 24, of a device
for unrolling the strands that is not shown in the figures.
[0036] In the case of the apparatus shown here, the impregnating
device 25 is assigned a discharge device 26 for excess resin that
is only schematically represented. A further discharge device 27 is
assigned to the gel zone region 21. This discharge device 27 serves
for discharging low-viscosity resin from the already initiated
reaction.
[0037] In the case of the apparatus shown here, all four
positioning means 15 to 18, the impregnating device 25, the
individual components of the mold 23 and the pulling device 24 can
be moved, in particular can be moved back and forth, in the
direction of production 13 and counter to the direction of
production 13 for a short time (periodically) at preferably regular
time intervals. For this purpose, each positioning means 15 to 18,
the impregnating device 25, the mold 23 and the pulling device 24
are particularly assigned a motion element that is not shown in the
figures. This may be a reversible linear drive, the movement axis
of which runs in the direction of production 13. It is also
conceivable to bring about the back-and-forth movements of the
positioning means 15 to 18, the impregnating device 25, the mold 23
and/or the pulling device 24 by actuators, for example piezos.
[0038] A conceivable alternative refinement of the apparatus
envisages moving the mold 23 as a whole back and forth. Then, the
individual components of the mold 23 carry out movements
simultaneously. For this purpose, the mold 23 may be formed by
components that are joined together and not spaced apart from one
another, by the heating device 19, the gel zone region 21 and the
final reaction region 22 following one another directly.
[0039] The individual positioning means 15 to 18 of the positioning
device 14 are formed like orifice plates. For this purpose, each
positioning means 15, 16, 17, 18 consists of a plate running
transversely with respect to the direction of production 13. The
plates may be of the same thickness, or else have different
thicknesses--as in the exemplary embodiment shown--by the
positioning means 17 and 18 being thicker than the positioning
means 15 and 16, to be precise approximately twice as thick. Each
of the plate-like positioning means 15 to 18 has a passage 28, 29,
30, 31. The reinforcement 11 is led through the passages 28, 29, 30
and 31 of the positioning means 15, 16, 18 in the direction of the
impregnating device 25. The passages 28 to 31 of the individual
positioning means 15 to 18 are of different sizes. In the direction
of production 13, the passages 28 to 31 of the positioning means 15
to 18 become increasingly smaller. The first positioning means 15
in the direction of production 13 accordingly has the largest
passage 28, while the last positioning means 18 before the
impregnating device 25, seen in the direction of production 13, has
the smallest passage 31. The orifice-plate-like form of the
positioning means 15 to 18, with the passages 28 to 31 becoming
increasingly smaller in the direction of production 13, has the
effect that the reinforcement 11 is bundled by the positioning
means 15 to 18 in the direction of production 13 and increasingly
compacted, whereby, in the direction of production 13, the
reinforcement 11 is brought together in a funnel-like manner in the
direction of the impregnating device 25.
[0040] In the exemplary embodiment shown in FIG. 1, the positioning
means 15 to 18 are spaced equally apart from one another. The
intermediate spaces between successive positioning means 15 to 18
are approximately the same size. In the exemplary embodiment shown,
the intermediate spaces between two respective positioning means 15
to 18 are approximately the thickness of the positioning means 17
or 18.
[0041] The pulling device 24 is formed such that it can be released
from the finished plastic profile 10. For this purpose, the pulling
device 24 has, for example, grippers that can be moved together and
apart. When the pulling device 24 securely holds the plastic
profile 10, it can be moved forward by the pulling device 24 in the
direction of production 13. When the pulling device 24 is released
from the plastic profile 10, the pulling device 24 can be moved
back counter to the direction of production 13.
[0042] The pulling device 24 may possibly be provided with a
cooling arrangement. The cooling arrangement of the pulling device
24 is provided in particular whenever it is intended to produce
with the apparatus a plastic profile 10 in which the reinforcement
11 is embedded in a thermoplastic material 12. The pulling device
24 may be designed in particular for producing a plastic profile 10
from a thermoplastic material 12 and also for compressing the
plastic profile 10 in the circumferential direction. Then, the
demolding of the plastic profile 10 takes place in the compressible
pulling device 24. This demolding takes place after a calibration
of the plastic profile 10. For this purpose, the pulling device 24
may be dividably formed, by consisting of two or more parts, in
particular press parts, that can be moved together and apart
transversely with respect to the direction of production 13. With
the press parts of the pulling device 24 moved together, there
takes place a demolding under pressure or calibration of the
plastic profile 10 surrounded all around by the press parts. With
the press parts moved apart, the pulling device 24 is detached from
the lateral surface of the plastic profile 10, whereby the pulling
device 24 can be moved back counter to the direction of production
13 without contacting the lateral surface of the plastic profile
10.
[0043] Linear drives or actuators for moving the pulling device 24
forward and back are not represented in FIG. 1. Similarly, FIG. 1
does not include any representation of such drives or actuators for
moving the gel zone region 21, the final reaction region 22 and the
heating device 19 of the mold 23 and also the impregnating device
25. Such linear drives may be formed in a way known per se. The
actuators may consist of piezos. The latter lead to relatively
small traveling distances. By contrast, linear drives allow greater
traveling distances, to be precise of any desired length.
[0044] The method according to the invention is described in more
detail below with reference to FIGS. 1 and 2.
[0045] In the following description of the method, it is assumed
that all four positioning means 15 to 18, the impregnating device
25, all parts of the mold 23 and the pulling device 24 can be moved
back and forth in the direction of production 13 and counter to the
direction of production 13 periodically by the same distance in
each case, the movement of the positioning means 15 to 18, the
impregnating device 25, the parts of the mold 23 and the pulling
device 24 being phase-shifted. During the movement back and forth
of the aforementioned movable parts of the apparatus, the
reinforcement 11 is kept taut over the entire length.
[0046] In FIG. 2, the sequences of movements are represented in a
time-distance diagram. The time t is plotted on the x axis and the
distance s is plotted on the y axis. In the case of the
time-distance diagram shown here, it is assumed that the
positioning means 15 and 16 on the one hand and the positioning
means 17 and 18 on the other hand are moved simultaneously. In the
time-distance diagram of FIG. 2, the sequences of movement of the
positioning means 15 and 16, the positioning means 17 and 18, the
impregnating device 25, the heating device 19 with the cooled inlet
20, the gel zone region 21, the final reaction region 22 and the
pulling device 24 are represented one above the other from the
bottom upward. The opening of the grippers of the pulling device 24
is represented in vertical regions. Following thereafter in time is
the time period in which the grippers of the pulling device 24 are
open, represented by a cross-hatched bar. Represented alongside by
vertical hatching is the phase of the closing of the grippers. The
(white) regions of a longer time between the vertical bars for the
opening of the pulling device 24, the open pulling device 24 and
the closing of the pulling device 24, represent time phases in
which the grippers of the pulling device 24 are closed. Each of
these time phases is greater by a multiple than the time phase in
which the grippers of the pulling device 24 open, close and are
open.
[0047] The direction of the distance s represented on the y axis in
FIG. 2 corresponds to the movement of the individual components of
the apparatus counter to the direction of production 13.
Accordingly, a movement in the direction of the y axis that is
represented in FIG. 2 concerns a movement counter to the direction
of production 13 of the plastic profile 10.
[0048] Represented at the top in FIG. 2 is the sequence of
movements of the pulling device 24. Accordingly, with its grippers
open, the pulling device 24 moves relatively quickly counter to the
direction of production 13. During the subsequent closing of the
grippers of the pulling device 24, the pulling device 24 is
stationary. Subsequently, with the grippers closed, the pulling
device 24 is slowly moved forward in the direction of production
13, to be precise approximately in half the time in which the
pulling device 24 is closed during a respective movement cycle. The
movement described above of the pulling device 24 is repeated for
each movement cycle.
[0049] The movements of all the other components of the apparatus,
to be specific the final reaction region 22, the gel zone region
21, the heating device 19 with the cooled inlet 20, the
impregnating device 25, the positioning means 17 and 18 and the
positioning means 15 and 16, proceed in accordance with the same
pattern of movements, but are phase-shifted--as can be seen from
FIG. 2--to be precise with respect to the next-following device, by
half the time in which the grippers of the pulling device 24 are
opened, are open and are closed (vertical bars of FIG. 2). The
final reaction region 22, upstream of the pulling device 24, is
stationary while the pulling device 24 is opened, is open and is
closed. Once the pulling device 24 is closed, the final reaction
region 22 is moved in the direction of production 13, to be precise
always approximately less than half the time in which the pulling
device 24 is closed. After a brief pause, the final reaction region
22 is then moved back counter to the direction of production 13, to
be precise at the same speed and by the same distance as the final
reaction region 22 was previously moved forward in the direction of
production 13. The same movements are carried out with the same
offset in time by the gel zone region 21, the heating device 19
with the cooled inlet 20, the impregnating device 25, the
positioning means 17 and 18 and the positioning means 15 and
16.
[0050] It is clear from FIG. 2 that the same movements of all the
components of the apparatus apart from the pulling device 24 follow
one another with an offset in time, but partially overlap one
another. The time offset is chosen such that the movement of the
positioning means 15 and 16 at the beginning of the apparatus is
offset with respect to the movement of the final reaction region by
half the time in which the grippers of the pulling device 24 are
closed.
[0051] As a departure from the representation of FIG. 2, all four
positioning means 15 to 18 may also be moved back and forth one
after the other independently of one another with a small time
offset. It is also conceivable to move only two positioning means,
for example the positioning means 15 and 17 or the positioning
means 16 and 18, periodically back and forth along the plastic
profile 10, while the other two positioning means 15, 17 or 16, 18
are not moved back and forth.
[0052] The phased moving back and forth of the individual
components of the apparatus, in particular according to FIG. 2, has
the effect that individual regions of the reinforcement 11 are
alternately subjected to tensile loading or compressive loading,
that is to say are compressed. It is also conceivable to perform
the periodically successive movements of individual components of
the apparatus such that the tensile loading that is exerted on the
reinforcement 11 as it passes through the apparatus is entirely or
partially reduced periodically from region to region. The tensile
loads that are exerted on the reinforcement 11 during the
production of the plastic profile 10, changing periodically from
region to region, cause a snake-like weaving of the reinforcement
11 through the individual components of the apparatus, whereby the
constriction or transverse contraction exerted on the reinforcement
during the production of the plastic profile 10 is eliminated, or
at least reduced, and as a result the form of the reinforcement 11
does not change during the production of the plastic profile 10 and
the position of the reinforcement 11 in the plastic 12 remains
unchanged during the production of the plastic profile 10.
[0053] A method that differs from this is conceivable, one in which
only the pulling device 24 and at least one of the positioning
means 15 to 18 are moved periodically back and forth with respect
to the direction of production 13. As a result, a periodic
portion-by-portion reduction or elimination of the tensile forces
exerted on the reinforcement 11 takes place during the production
of the plastic profile 10, also periodically allowing spaced-apart
compressions to occur in the reinforcement 11. It is also prevented
in this way that the reinforcement 11 contracts or is displaced in
an undesirable way during the bundling and compression, that is to
say upstream of the impregnating device 25 and the mold 23.
[0054] FIGS. 3 and 4 show a further exemplary embodiment of the
invention described above. This exemplary embodiment may also
constitute an independent invention.
[0055] In FIGS. 3 and 4, only part of an apparatus for producing
the plastic profile provided with the reinforcement 11 is
schematically represented. The part concerned here is a mold 32,
which can be changed in its form such that plastic profiles of any
desired shapes can be produced with it, to be precise not only the
straight plastic profile 10 that is shown in FIG. 4 but also a
curved plastic profile 33, which may be both reinforced and
unreinforced. Like the plastic 12 of the plastic profile 10, the
plastic 12 for the plastic profile 33 may be a thermoset or a
thermoplastic.
[0056] The mold 32 is formed by multiple mold portions 34 following
one another at a distance in the direction of production 13. In the
exemplary embodiment shown, the mold 32 consists of four identical
mold portions 34, which enclose in one piece the entire
circumference of the plastic profile 10, 33 in the manner of a
ring. The mold 32 may, however, also have a greater or smaller
number of mold portions 34, which may possibly also be differently
formed. Each mold portion 34, which in the exemplary embodiment
shown is formed in the manner of a plate, is provided with a
central molding passage 35. In the present case, all the molding
passages 35 are identically formed. However, it is also conceivable
that the molding passages 35 of at least some mold portions 34 are
differently formed.
[0057] The molding passage 35 in each mold portion 34 is provided
with a profile or shape that changes in the direction of production
13. In the exemplary embodiment of FIGS. 3 and 4, the narrowest
point of each molding passage 35 is in the center of the plate-like
mold portion 34. From here, the molding passage 35 widens toward
the opposing outer surfaces of the respective mold portion 34, so
that the contour of each molding passage 35 is uniformly convex. In
FIGS. 3 and 4, the cross section of each molding passage 35 is of
an arcuate form, to be precise an approximately semicircular form.
However, there may also be other cross sections, for example
triangular cross sections, elliptical cross sections or the like.
At least at the narrowest point in the center of the mold portion
34 concerned, the molding passage 35 corresponds to the cross
section of the plastic profile 10 to be produced.
[0058] The fact that the size of each molding passage 35 changes in
the longitudinal direction 36 of the respective molding passage 35
means that the circumferential surface of each molding passage 35
is convex. Only in a plane in which the narrowest point of the
respective molding passage 35 lies, in the exemplary embodiment
shown the center of the respective mold portion 34, is there
contact of the molding passage 35 with the outer surface of the
plastic profile 10 to be produced. This makes it possible to
position the mold portions 34 obliquely in such a way that the
longitudinal direction 36 of the molding passage 35 of each mold
portion 34 runs in different directions. This allows the production
not only of straight plastic profiles 10 but also of a curved
plastic profile 33 (FIG. 3). By obliquely positioning the mold
portions 34 appropriately, a plastic profile with any desired shape
can be produced. The plastic profile may be both two-dimensionally
and three-dimensionally curved. In the exemplary embodiment of FIG.
4, all the mold portions 34 of the mold 32 run parallel to one
another at a small distance, whereby the longitudinal directions 36
of all the molding passages 35 lie on a common straight line, to be
specific the center line of the straight plastic profile 10 to be
produced. If, on the other hand, the mold portions 34 are tilted
according to the representation in FIG. 3, to be precise preferably
to the same extent and in the same direction, the curved plastic
profile 33 that is shown in FIG. 3 is produced. Then, the
longitudinal directions 36 of the molding passages 35 of the mold
portions 34 run tangentially with respect to the longitudinal
center axis 37 of the curved plastic profile 33.
[0059] With preference, the mold portions 34 are formed from
different materials, in order to reduce the friction on the lateral
surface or the matrix of the plastic profile 10, 33 to be produced.
For example, the first mold portion 34 in the direction of
production 13 could be formed from steel, preferably high-grade
steel. The then-following mold portion 34 could be formed from
copper. The other mold portions 34 may be formed from thermoplastic
material, for example polyoxymethylene, or aluminum.
[0060] It is also conceivable to cool all or only selected mold
portions 34, in particular the mold portions 34 lying downstream in
the direction of production 13, and/or to heat at least the first
mold portions 34.
[0061] The method for producing plastic profiles 10, 33 having any
desired shapes proceeds as follows with the mold 32 described
above:
[0062] Depending on the desired form of the plastic profile 10, 33
to be produced, the mold portions 34 are aligned in relation to one
another and fixed. For the production of the straight plastic
profile 10, all the mold portions 34 are arranged in relation to
one another such that they run parallel to one another, to be
precise preferably at equal distances. The longitudinal center axes
or longitudinal directions 36 of the molding passages 35 of all the
mold portions 34 then lie on a common line, which corresponds to
the straight longitudinal center axis 37 of the non-curved plastic
profile 10 (FIG. 4).
[0063] If, on the other hand, the curved plastic profile 33 is to
be produced, preferably all the mold portions 34 are tilted
uniformly and in the same direction in relation to one another, to
be precise such that the center planes of all the mold portions 34
converge at a common point. In this case, the longitudinal center
axes 36 of the molding passages 35 of all the mold portions 34 lie
tangentially on the arcuate longitudinal center axis 37 of the
plastic profile 33. If the mold portions 34 are tilted
multi-axially, three-dimensionally curved plastic profiles can be
produced.
[0064] It is conceivable that at least one mold portion 34, the
first with respect to the direction of production 13, is heated,
while at least the last mold portion 34 serves for cooling the
plastic profile 10 or 33 to be produced. The mold portions 34 to be
cooled may be formed from a material having a relatively smooth and
slidable surface, for example an appropriate plastic, but also
aluminum, bronze or copper. By contrast, the respectively heated
mold portion is formed from a heat-resistant material, for example
steel, in particular a chrome-like steel, but possibly also
aluminum, copper or bronze.
LIST OF DESIGNATIONS
[0065] 10 plastic profile [0066] 11 reinforcement [0067] 12 plastic
[0068] 13 direction of production [0069] 14 positioning device
[0070] 15 positioning means [0071] 16 positioning means [0072] 17
positioning means [0073] 18 positioning means [0074] 19 heating
device [0075] 20 cooled inlet [0076] 21 gel zone region [0077] 22
final reaction region [0078] 23 mold [0079] 24 pulling device
[0080] 25 impregnating device [0081] 26 discharge device [0082] 27
discharge device [0083] 28 passage [0084] 29 passage [0085] 30
passage [0086] 31 passage [0087] 32 mold [0088] 33 plastic profile
[0089] 34 mold portion [0090] 35 molding passage [0091] 36
longitudinal direction [0092] 37 longitudinal center axis
* * * * *