U.S. patent application number 12/213552 was filed with the patent office on 2008-10-30 for process for extruding a profile on a glazing and a glazing having an extruded profile.
This patent application is currently assigned to Pilkington Italia S.p.A.. Invention is credited to Ginetto Biginato, Saverio Lomartire, Ciro Paudice, Sergio Pulcini.
Application Number | 20080268198 12/213552 |
Document ID | / |
Family ID | 8184429 |
Filed Date | 2008-10-30 |
United States Patent
Application |
20080268198 |
Kind Code |
A1 |
Paudice; Ciro ; et
al. |
October 30, 2008 |
Process for extruding a profile on a glazing and a glazing having
an extruded profile
Abstract
A process for extruding a profile on a glazing comprises
extruding the profile through a nozzle while it is being moved by a
drive device along a first edge of a glazing, around a corner of
the glazing and along a second edge of the glazing, the nozzle
being rotated relative to the drive device as it moves around the
corner. The extruded profile comprises a first edge portion
extending along a first edge of the glazing, a sharp corner portion
extending around a sharp corner of the glazing and a second edge
portion extending along a second edge region of the glazing, the
portions of the profile being continuous.
Inventors: |
Paudice; Ciro; (Vasto CH,
IT) ; Lomartire; Saverio; (Torino TO, IT) ;
Biginato; Ginetto; (Collegno TO, IT) ; Pulcini;
Sergio; (Volpiano TO, IT) |
Correspondence
Address: |
BUCHANAN, INGERSOLL & ROONEY PC
POST OFFICE BOX 1404
ALEXANDRIA
VA
22313-1404
US
|
Assignee: |
Pilkington Italia S.p.A.
San Salvo CH
IT
NKE S.p.A.
Alpignano (TO)
IT
|
Family ID: |
8184429 |
Appl. No.: |
12/213552 |
Filed: |
June 20, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10469595 |
Feb 27, 2004 |
7404711 |
|
|
PCT/EP02/02034 |
Feb 26, 2002 |
|
|
|
12213552 |
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Current U.S.
Class: |
428/81 ;
264/252 |
Current CPC
Class: |
Y10T 156/172 20150115;
B29C 48/33 20190201; B29C 48/07 20190201; B29C 48/155 20190201;
B29C 48/12 20190201; B29C 48/06 20190201 |
Class at
Publication: |
428/81 ;
264/252 |
International
Class: |
B32B 3/02 20060101
B32B003/02 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 2, 2001 |
EP |
01830147.3 |
Claims
1. A process for extruding a profile on to a glazing comprising,
extruding the profile through an extrusion nozzle while the
extrusion nozzle is being moved by drive means along a first edge
region of the glazing, around a corner region of the glazing and
along a second edge region of the glazing, characterised by
rotating the extrusion nozzle relative to the drive means as the
extrusion nozzle is moved around the corner region of the
glazing.
2. A process as claimed in claim 1, wherein the extrusion nozzle is
rotated about a rotation axis which is maintained in a
substantially orthogonal orientation to the surface of the glazing
as the profile is being extruded.
3. A process as claimed in claim 1, further comprising maintaining
the material to be extruded at a pre-determined temperature before
extrusion.
4. A process as claimed in claim 3, wherein the pre-determined
temperature is in the range 30.degree. C. to 240.degree..
5. A process as claimed in claim 4 wherein the pre-determined
temperature is in the range 30.degree. C. to 140.degree. C.
6. A process as claimed in claim 4 wherein the pre-determined
temperature is in the range 140.degree. C. to 240.degree. C.
7. A process as claimed in claim 1, wherein the material to be
extruded comprises polyurethane or a thermoplastic elastomer.
8. A glazing having an extruded profile, the extruded profile
comprising a first edge portion extending along a first edge region
of the glazing, a sharp corner portion extending around a sharp
corner region of the glazing and a second edge portion extending
along a second edge region of the glazing, characterised in that
the first edge portion, the sharp corner portion and the second
edge portion are continuous.
9. A glazing as claimed in claim 8, wherein the sharp corner
portion of the profile has a radius of 5 cm or below.
10. A glazing as claimed in claim 8, wherein the polymer comprises
polyurethane or a thermoplastic elastomer.
Description
[0001] This application is a divisional of prior application Ser.
No. 10/469,595 having a filing date of Feb. 27, 2004, the entire
content of which is incorporated herein by reference, which is a
U.S. national stage application based on International Application
No. PCT/EP02/02034 having an international filing date of Feb. 26,
2002, the entire content of which is incorporated herein by
reference. This application also claims priority to European
Application No. 01830147.3 filed on Mar. 2, 2001, the entire
content of which is incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to apparatus and processes for
extruding profiles on to glazings, and glazings having extruded
profiles.
BACKGROUND DISCUSSION
[0003] It is known to provide glazings, in particular vehicle
glazings, with extruded profiles around the margin of the glazing.
Profiles on vehicle glazings act as weather seals, and improve the
appearance of glazings when the glazings are in position in a
vehicle body. Profiles may also be used to receive and retain an
adhesive bead used in fixing the glazing in position in the vehicle
body. The material used for extruded profiles usually comprises a
suitable polymer, for example, polyurethane or a thermoplastic
elastomer.
[0004] The conventional extrusion process for extruding polymer
profiles on to glazings, usually involves extruding the polymer
material through an extrusion nozzle, incorporated in an extrusion
head, whilst the head is driven along a path along which it is
desired to extrude the profile. The extrusion head is usually
driven by a robot which is programmed to follow the extrusion
path.
[0005] Unfortunately, there are disadvantages associated with
conventional extrusion.
[0006] When extruding a profile on a curve, for example around a
corner of a glazing, there is a difference in circumference between
the inner and outer edge of the profile. As a consequence of this,
extruded profiles can exhibit imperfections at corners, a problem
which is particularly acute with sharp corners (i.e. a corner
having a small radius or width).
[0007] The problem of extruding on a curve, especially around sharp
corners, has been addressed in U.S. Pat. No. 5,108,526. U.S. Pat.
No. 5,108,526 discloses a polymer extrusion die apparatus wherein
polymer is supplied to the die head by means of at least one supply
line. The supply line(s) delivers polymer under pressure to at
least one supply channel, at least one of which includes means for
controlling the flow of polymer therethrough. By using the means
for controlling the flow of polymer through a supply channel, the
flow of polymer through the inner or outer portion of the die
orifice can be controlled. On a corner, the supply channel to the
outer portion of the die is controlled to have a higher polymer
flow than the inner portion resulting in an improved profile being
extruded.
[0008] However, there is a further problem in extruding profiles on
curves, especially extruding around sharp corners. Commercially
available robots typically have six axes of motion which may be
insufficient to allow precise extrusion around relatively sharp
corners. Thus, it may be difficult to extrude a profile which
follows the edge of the glazing precisely when the profile is to be
extruded around a relatively sharp corner.
[0009] U.S. Pat. No. 5,316,829 discloses extruding a profile on a
glazing and then after extrusion, and in a separate step,
completing the profile with a complementary component. This is
accomplished by using a mould that rests on the glazing, connecting
the mould to the profile and injecting into the mould a hardenable
material which adheres to the polymer. U.S. Pat. No. 5,316,829
further discloses that where a glazing has a pointed corner where
it is difficult to extrude a profile, it is possible to stop the
extrusion in the corner, or if the profile has already been
produced, to remove the profile after hardening, and to complete or
repair it by casting the profile part.
[0010] This procedure has disadvantages in that moulding corner
parts in a separate step complicates manufacturing and is
expensive. Furthermore, a moulded corner will either consist of a
material different to that of the extruded profile, or will consist
of the same material but produced using different process
parameters to those used to produce the extruded profile. As a
consequence, the corner portion and the extruded portion of the
profile may have different material properties including different
adhesion properties. For example, they may exhibit different
wettability to adhesives and/or to water (e.g. rain water) and may
have different ageing properties. Also, the primer used to bond the
material to glass may be degraded by the heat generated by the
mould, or may consist of a different material and therefore the
adhesion value may be different from that of the extruded profile.
Such a difference in materials properties and/or adhesion
properties results in the profiled glazing being less reliable in
use and in the interface between the corner portion and extruded
portion being visible as a seam in the profile. A seam in the
profile is unattractive and, therefore, undesirable in a commercial
product.
SUMMARY
[0011] An aim of the present invention is to address the problem of
extruding around curves, especially sharp corners, and to mitigate
disadvantages associated with the prior art.
[0012] The present invention accordingly provides, in a first
aspect, apparatus for extruding a profile on a glazing, the
apparatus comprising an extrusion head having an extrusion nozzle
through which the profile may be extruded, the extrusion head being
mounted on drive means for moving the extrusion head, characterised
by rotation means arranged to rotate the extrusion nozzle relative
to the drive means.
[0013] This is advantageous because rotating the nozzle relative to
the drive means allows the extrusion head to extrude around
corners, especially sharp corners. Thus, a continuous profile may
be extruded around corners, which will tend to provide a more
reliable part because the corner profiles will be made of the same
material (extruded under very similar processing conditions) to at
least part of the rest of the profile.
[0014] The drive means will usually comprise a robot. If the drive
means comprises a conventional robot with six axes of movement, the
independent rotation axis will provide a seventh axis of movement
associated with the extrusion head.
[0015] Normally, the extrusion head will further comprise an inlet
for coupling the head to a supply of the material to be extruded.
In such a case, it is advantageous if the rotation means is
arranged to rotate the extrusion nozzle relative to the inlet,
because then the inlet and material supply (and/or a material
supply hose coupled to the inlet) need not rotate when the nozzle
does. Rotation relative to the inlet may be achieved if the
rotation means comprises a shaft connected to the nozzle at a one
end and rotatably mounted to the inlet portion of the extrusion
head at the other end.
[0016] Preferably, the rotation means is arranged to rotate the
extrusion nozzle about an axis passing through the body of the
extrusion head. More preferably, the rotation means is arranged to
rotate the extrusion nozzle about an axis passing through the
extrusion nozzle, most preferably through the centre of the
extrusion nozzle.
[0017] The apparatus may further comprise a motor for rotating the
rotation means. The motor will preferably be controllable via the
robot controller (i.e. the programme and/or processor which
controls the robot itself).
[0018] To improve the flow of the material to be extruded, the
apparatus may further comprise heating means to maintain the
material to be extruded at a pre-determined temperature.
[0019] The part of the apparatus which is most usefully maintained
at a pre-determined temperature is the extrusion nozzle. If
present, the inlet and/or the shaft may also be maintained at a
pre-determined temperature (which may be the same or different to
the temperature of the nozzle) by the heating means.
[0020] The invention also provides an extrusion head for extruding
a profile on to a glazing, the extrusion head comprising an
extrusion nozzle through which the profile may be extruded,
characterised by rotation means forming part of the extrusion head,
the rotation means being arranged to rotate the extrusion
nozzle.
[0021] The present invention provides, in a second aspect, a
process for extruding a profile on to a glazing comprising,
extruding the profile through an extrusion nozzle while the
extrusion nozzle is being moved by drive means along a first edge
region of the glazing, around a corner region of the glazing and
along a second edge region of the glazing, characterised by
rotating the extrusion nozzle relative to the drive means as the
extrusion nozzle is moved around the corner region of the
glazing.
[0022] This is advantageous because the process will thereby
provide a continuous profile which will have substantially
identical material properties in the corner and edge portions of
the profile, and which will, therefore, improve the reliability of
the profile.
[0023] Glazings on which profiles are extruded may be flat or
curved and it is advantageous if the profile is extruded whilst the
extrusion nozzle is rotated about a rotation axis which is
maintained in a substantially orthogonal (i.e. perpendicular)
orientation to the surface of the glazing as the profile is being
extruded.
[0024] However, in some embodiments of the invention, the angle of
the rotation axis may be varied away from an orthogonal orientation
as the nozzle moves along the extrusion path. This is advantageous
because the rotation of the nozzle about the rotation axis can
thereby be advanced or delayed before approaching a corner, which
provides finer control over the profile, and may enable even
narrower corners to be extruded. The angle of the axis with respect
to the surface of the glazing will usually be varied in the plane
of the extrusion path.
[0025] Preferably, the process further comprises maintaining the
material to be extruded at a pre-determined temperature before
extrusion. The pre-determined temperature will depend on the
properties of the material to be extruded and, usually, the
pre-determined temperature will be in the range 30.degree. C. to
240.degree. C. For example, the pre-determined temperature may be
in the range 30.degree. C. to 140.degree. C. or in the range
140.degree. C. to 240.degree. C.
[0026] The material extruded by the process will normally be a
polymer material, comprising, for example, polyurethane (in which
case the pre-determined temperature range is preferably in the
range 30.degree. C. to 140.degree. C.) or a thermoplastic elastomer
(in which case the pre-determined temperature range is preferably
in the range 140.degree. C. to 240.degree. C.). Especially suitable
thermoplastic polymers are vulcanised thermoplastic polymers, for
example those sold under the trade name FORPRENE.
[0027] Glazings having extruded profiles obtainable by the process
of the invention, have uses in buildings, but will be most often
used in vehicle glazings. Vehicle glazings include windscreens,
back windows (often referred to as backlights), side windows or
sunroofs.
[0028] Accordingly, the present invention provides, in a third
aspect, a glazing having an extruded profile, the extruded profile
comprising a first edge portion extending along a first edge region
of the glazing, a sharp corner portion extending around a sharp
corner region of the glazing and a second edge portion extending
along a second edge region of the glazing, characterised in that
the first edge portion, the sharp corner portion and the second
edge portion are continuous.
[0029] A continuous profile is advantageous because the first edge
portion, the corner portion and the second edge portion will have
substantially identical material properties, which improves the
reliability of the profile. Furthermore, a continuous profile will
have no seams between the edge portions and the corner portion
which improves the attractiveness of the profile.
[0030] The sharp corner portion of the profile will usually have a
radius of 5 cm or below, more usually of 3 cm or below and most
usually of 2 cm or below.
[0031] The profile will usually comprise a polymer, for example
polyurethane or a thermoplastic elastomer (especially a vulcanised
thermoplastic elastomer).
BRIEF DESCRIPTION OF THE DRAWING FIGURES
[0032] By way of illustration, embodiments of the present invention
will now be described in more detail with reference to the
accompanying drawings in which:
[0033] FIG. 1 shows a vertical section through an extrusion head
according to the invention.
[0034] FIGS. 2a, 2b and 2c show schematically, in plan view, a
polymer profile being extruded on to a glazing by a process
according to the invention.
[0035] FIG. 3 shows a vertical section through an extruded profile
according to the invention.
DETAILED DESCRIPTION
[0036] Referring to FIG. 1, an extrusion head 2 comprises a
structural cage 12 of support struts 14, an upper support plate 16
and a lower support plate 18. The lower support plate 18 is hollow
and contains gears (not shown) used in the transmission system 20.
An inlet portion 8 is mounted on the support cage 12 (for clarity,
the mounting are not shown) and has an inlet 9 for coupling the
inlet portion 8 of the head 2 to a supply of the material to be
extruded. The material will usually be supplied to the head through
the inlet 9 by a hose (not shown).
[0037] A hollow shaft 6 is coupled to the inlet portion 8 by means
of a rotation joint 10 which allows the shaft to rotate, relative
to the inlet portion 8, about a rotation axis A. In the embodiment
illustrated, the rotation axis A coincides with the longitudinal
axis of the nozzle 4 and the shaft 6.
[0038] The hollow shaft 6 ends with an extrusion nozzle 4 through
which the profile (not shown) may be extruded. The internal
arrangement of inlet portion 8, shaft 6 and extrusion nozzle 4 is
such that material to be extruded will, under pressure, flow from
the inlet portion 8 through the shaft 6 (whether stationary or
rotating relative to the inlet portion 8) and through extrusion
nozzle 4.
[0039] The hollow shaft 6 is coupled by a transmission system 20
(part of which hidden in FIG. 1 by lower support plate 18) to an
electric motor 22 which drives the rotation of shaft 6 and nozzle
4. The shaft 6 rotates in a collar 24 where the shaft passes
through the lower support plate 18.
[0040] A pantograph shock absorber 26 (which comprises a spring
mechanism not shown in FIG. 1) is coupled to the shaft 6 between
the collar 24 and the nozzle 4. The pantograph 26 is used to keep
the pressure of the nozzle 4 against the glass surface constant and
thus to maintain a constant distance between the nozzle and the
glass surface, independently of any imperfection (e.g. waviness) of
the glass edge.
[0041] The areas of the extrusion head 2 which will be in contact
with the material to be extruded, especially the inlet 9, inlet
portion 8, shaft 6 and nozzle 4 are thermo-regulated by heaters
(not shown) capable of maintaining a pre-determined temperature in
the range room temperature to about 300.degree. C. The other
components of the extrusion head 2 which are not heated (and/or
which may be adversely affected by heat) will usually be
insulated.
[0042] The extrusion head 2 as shown in FIG. 1 is fixed to the
mounting flange 28 of the operating arm of a robot. The robot is
used to drive the extrusion head over the desired extrusion path.
Typical commercially available robots have six rotation axes. The
extrusion head 2 when fixed to a commercially available robot
provides a seventh and independent (i.e. separate to other axes of
rotation, for example, the rotation axes of the robot) rotation
axis for improved flexibility and control of extrusion, especially
around sharp corners of glazings. Usually, the robot will be used
to control the rotation of the nozzle 4 of the extrusion head 2 by
connecting the motor 22 to the robot (not shown).
[0043] During the process of extrusion using the extrusion head 2,
the axis A will usually be maintained substantially orthogonal to
the surface of the glazing. However, it may be advantageous to vary
the angle between the axis (i.e. the independent rotation axis) and
the surface of the glazing so as to provide finer control over the
extruded profile.
[0044] The process of extrusion of a profile on to a glazing (which
will usually be either flat or curved glass) is shown schematically
in FIGS. 2a, 2b and 2c. Referring to FIG. 2a, a sheet of glass 30
intended as a vehicle glazing has substantially the shape of a
trapezium (in practice, the glazing 30 will be bent (i.e. curved)
and, in consequence will have slightly curved edges). An extrusion
nozzle 4 (for clarity only the extrusion nozzle 4 of the extrusion
head 2 is shown in FIG. 2) is driven along the lower edge 32 of the
sheet of glass 30 by a robot (not shown). As it is so driven, a
polymer profile 34 of a vulcanised thermoplastic elastomer
(obtained from So.F.Tter Srl and supplied under the trade name
FORPRENE) is extruded along the lower edge 32 by the extrusion
nozzle 4 until the nozzle 4 has reached the corner 36 of the sheet
of glass 30 (referring to FIG. 2b).
[0045] At the corner 36 of the sheet of glass 30, the extrusion
nozzle 4 is rotated so that it is orientated to an extrusion path
along the right side edge 38 of the sheet of glass 30. The robot
drives the extrusion nozzle 4, and the nozzle 4 extrudes polymer
profile 34, along the right side edge 38.
[0046] As is shown in FIG. 2c, polymer profile 34 is extruded
continuously from the extrusion nozzle 4 whilst it is driven along
the lower edge 32, around the corner 36 and along the right side
edge 38 so that a continuous polymer profile 34 is extruded along
those edges and around the sharp corner 36. The polymer profile 34
will be seamless around the corner and the portions of the profile
before, around and after the corner will have substantially the
same material properties including substantially the same adhesion
properties.
[0047] Referring to FIG. 3, a polymer profile 40 extruded on to the
edge of a vehicle glazing 42, of bent and toughened glass,
comprises a lip portion 44 projecting over the edge of the glazing
and a spacing portion 46 projecting substantially vertically from
the surface of the glazing 42. When the glazing 42 is glazed into
an opening in a vehicle body (not shown), the spacing portion 46 is
intended to space the glazing 42 from the vehicle body. The lip
portion 44 is intended to contact an opposed part of the vehicle
boy and bend around the edge of the glazing 42 so as to space the
glazing efficiently in the opening provided in the vehicle body,
form an improved weather seal and to protect the edge of the
glazing 42. The polymer profile comprises a vulcanised
thermoplastic elastomer but may alternatively be formed by
extrusion using any other material known to be suitable for
extruding profiles on to glazings, for example, polyurethane.
* * * * *