Plastic article or earthenware shaping or treating: apparatus – Stock pressurizing means operably associated with downstream... – Including auxiliary shaping means associated with molding...
Reexamination Certificate
2001-12-05
2004-06-29
Heitbrink, Tim (Department: 1722)
Plastic article or earthenware shaping or treating: apparatus
Stock pressurizing means operably associated with downstream...
Including auxiliary shaping means associated with molding...
C425S309000, C425S311000, C425S465000, C425S466000
Reexamination Certificate
active
06755638
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is directed to a method and apparatus for producing a continuous extrusion molding product with a varying profile. More particularly, the present invention is directed to a molding machine having shaping knives rotatable around axes substantially non-parallel to the flow direction of the extruded material.
2. Description of the Related Art
Molding products are useful for sealing spaces between, for example, the edge of a windshield and the body panel of a vehicle. In the case of automobile windshield molding, it is well known in the art that varying the profile of a molding strip along its length can obtain various advantages, for example the formation of water-draining channels for receiving water flowing on the surface of the windshield. Numerous designs for automobile windshield molding strips with a varying profile have been proposed.
FIGS. 1 and 2
illustrate one example of a molding strip with a varying profile for sealing the space between a windshield and an opening in the frame of a vehicle body. Molding strip
2
is a continuous plastic strip comprising three sections: an upper section
2
A mounted between the upper edge of the windshield
11
and the roof panel
12
, a side section
2
C mounted between the side edges of windshield
11
and the pillar panels
13
, and corner sections
2
B joining the upper section
2
A with side sections
2
C at the corners of windshield
11
. Molding strip
2
comprises exterior wing
21
including an inward wing portion
21
a
and an outward wing portion
21
b
, connecting portion
22
, and foot
24
.
Outward wing portion
21
b
is for covering the periphery of the vehicle body panels
12
,
13
and is of uniform thickness along its length. As illustrated in
FIG. 2
, the profile of molding strip
2
varies along the length of side section
2
C such that inward wing portion
21
a
gradually thickens from corner section
2
B to the central portion of side section
2
C. As inward wing
21
a
thickens, connecting portion
22
lengthens and sub-inward wing
21
c
diverges from inward wing
21
a
to form water drain channel
28
. Water drain channel
28
gradually widens and deepens towards the center of side section
2
C and then gradually becomes thinner and shallower towards the lower extreme of side section
2
C. The profile of corner section
2
B is the same as that of upper molding
2
A; the flexible quality of molding
2
allows it to be deformed and fitted around the corner of windshield
11
. Metal wire
23
is embedded in molding strip
2
to reinforce the strip.
FIG. 3A
shows a cross-sectional view of molding strip
2
installed between windshield
11
and roof panel
12
.
FIG. 3B
shows a cross-sectional view of molding strip
2
installed between windshield
11
and a central portion of pillar panel
13
. In
FIG. 3A
, the windshield
11
is received between foot
24
and inward wing
21
a
. In
FIG. 3B
, connecting portion
22
is lengthened and windshield
11
is received between sub-inward wing
21
c
and foot
24
. A water drain channel
28
is formed between inward wing
21
a
and sub-inward wing
21
c.
FIGS. 4 and 5
illustrate a prior art molding machine
3
for producing the molding strip
2
. Molding machine
3
comprises die
31
and shaping knives
32
and
33
. In
FIGS. 4 and 5
, plastic material to be extruded flows in a direction perpendicular to the plane of the illustrations. Die
31
is stationary and has an opening
34
in the shape of a vertically long rectangle, where the upper portion of the rectangle corresponds to the cross-sectional profile of exterior wing
21
. Specifically, the contour of portion
341
corresponds to the cross-sectional profile of outward wing
21
b
, the contour of portion
343
corresponds to the cross-sectional profile of inward wing
21
a
, and the contour of portion
345
corresponds to the cross-sectional shape of sub-inward wing
21
c.
Shaping knives
32
,
33
are rectangular plates supported by guides
32
a
and
32
b
, respectively, and are movable in the plane of the illustration, e.g., movable in a plane perpendicular to the flow direction of the plastic material to be extruded. Shaping knife
32
has an opening
35
with a contour corresponding to the cross-sectional profile of foot
24
. When in a first operational position illustrated in
FIG. 4
, shaping knife
32
is positioned on die
31
such that the openings
34
,
35
are in the cross-sectional shape of molding strip
2
before inward wing
21
a
is thickened. As the plastic material is extruded, shaft
32
d
connected to a converter
32
b
and motor
32
c
gradually moves shaping knife
32
to a second operational position illustrated in
FIG. 5
such that inward wing
21
a
is thickened. A reciprocal motion is performed to cause inward wing
21
a
to become gradually thinner.
Shaping knife
33
has a slanted edge
331
with a contour corresponding to the cross-sectional profile of water drain channel
28
. When in a first operational position illustrated in
FIG. 4
, shaping knife
33
is positioned outside of the flow of the plastic material. As the plastic material is extruded, shaft
33
d
connected to a converter
33
b
and motor
33
c
gradually moves shaping knife
32
to a second operational position illustrated in
FIG. 5
such that water drain channel
28
is formed. A reciprocal motion is performed to cause water drain channel
28
to become gradually less deep and thinner.
FIG. 6
illustrates another molding machine
100
of the prior art in which die
104
rotates about pin
103
in a plane perpendicular to the flow of the plastic material to be extruded such that the cross-sectional shape of opening
104
a
is changed during extrusion of the plastic material.
The molding machines of the prior art are able to produce molding products with varying profiles. However, because the movement of the dies is in a plane perpendicular to the flow of the plastic material, the streamlines of the flow of the plastic material around the edges of the dies are significantly disrupted, thereby causing wrinkles on the final product. Furthermore, sudden pressure changes in the portions of the flow may result in stagnation points where plastic material is trapped and hardened. This also results in wrinkles and even burrs on the final product. Finally, the movement of the dies between operational positions in the molding machines of the prior art causes a sudden increase in flow pressure against the dies. As a result, the parts of the molding machine suffer fatigue and wear-and-tear.
SUMMARY OF THE INVENTION
It is therefore an object of this invention to provide a method and apparatus for producing a continuous extrusion molding product with a varying profile, in which the molding machine has shaping knives rotatable around axes substantially non-parallel to the flow direction of the molten material to be extruded.
It is another object of this invention to provide a method and apparatus for producing a continuous extrusion molding product with a varying profile, in which the rotation of shaping knives around axes perpendicular or oblique to the flow direction of the molten material to be extruded allows the contour of the opening between the dies to be manipulated across a gradient of shapes and sizes to produce a smooth change in profile of the molded product.
It is yet another object of the invention to provide a method and apparatus for producing a continuous extrusion molding product with a varying profile, in which disruption of the flow and sudden pressure changes in portions thereof caused by the movement of shaping knives is significantly reduced, thereby reducing wrinkles and burrs on the final product.
According to a first aspect of the present invention, there is provided a molding machine for producing a molding product with varying profile comprising: a die with an inlet for receiving molten material, a channel, and an outlet, the channel directing the molten material from the inlet to the outlet along a first axis; a firs
Chen Chun-Chin
Liang Ting-Goang
Shih Hsi-Hsin
Wu Chung-Hsien
Heitbrink Tim
Professionals Auto Parts International Co., Ltd.
Sughrue & Mion, PLLC
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