U.S. patent application number 09/871523 was filed with the patent office on 2002-01-31 for method of forming a blow-molded plastic part having a living hinge.
Invention is credited to Schoemann, Michael P., Spagnuolo, Anthony, Stancu, Sorin.
Application Number | 20020011695 09/871523 |
Document ID | / |
Family ID | 23351980 |
Filed Date | 2002-01-31 |
United States Patent
Application |
20020011695 |
Kind Code |
A1 |
Stancu, Sorin ; et
al. |
January 31, 2002 |
Method of forming a blow-molded plastic part having a living
hinge
Abstract
A method of forming a carpeted plastic part includes positioning
a carpet between first and second mold halves, wherein the carpet
has a back surface. A non-reinforced plastic strip is positioned
adjacent a portion of the back surface of the carpet. A hollow
parison of reinforced plastic material is formed between the first
and second mold halves. The first and second mold halves are then
closed together to form a carpeted plastic part having a
thinned-down region of the reinforced plastic material adjacent the
plastic strip such that the plastic strip is sandwiched between the
thinned-down region and the carpet to form a flexible living
hinge.
Inventors: |
Stancu, Sorin; (Dearborn,
MI) ; Spagnuolo, Anthony; (Windsor, CA) ;
Schoemann, Michael P.; (Waterford, MI) |
Correspondence
Address: |
Christopher W. Quinn
Brooks & Kushman P.C.
22nd Floor
1000 Town Center
Southfield
MI
48075-1351
US
|
Family ID: |
23351980 |
Appl. No.: |
09/871523 |
Filed: |
May 31, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
09871523 |
May 31, 2001 |
|
|
|
09344774 |
Jun 28, 1999 |
|
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Current U.S.
Class: |
264/516 ;
156/245; 156/285 |
Current CPC
Class: |
B29C 49/04 20130101;
B29K 2995/0053 20130101; B29C 2049/203 20130101; B29C 49/24
20130101; B29L 2031/3005 20130101; B29C 2049/2095 20130101; B29C
49/251 20220501; B29C 49/20 20130101; B29L 2031/22 20130101; B29C
2049/4805 20130101 |
Class at
Publication: |
264/516 ;
156/285; 156/245 |
International
Class: |
B29C 049/20 |
Claims
What is claimed is:
1. A method of forming a plastic part with a living hinge
comprising: positioning a non-reinforced plastic strip between
first and second mold halves; forming a hollow parison of
reinforced plastic material between the first and second mold
halves; and closing the first and second mold halves together to
form a thinned-down region of glass-filled material adjacent the
plastic strip such that the plastic strip and the thinned-down
region form a flexible living hinge.
2. The method of claim 1, further comprising heating said plastic
strip prior to said step of positioning the plastic strip between
the first and second mold halves.
3. The method of claim 1, further comprising positioning a carpet
between the first and second mold halves.
4. The method of claim 3, wherein the non-reinforced plastic strip
is positioned between the carpet and the hollow parison.
5. The method of claim 3, wherein the hollow parison is positioned
between the non-reinforced plastic strip and the carpet.
6. The method of claim 1, wherein said step of positioning a
non-glass-filled plastic strip comprises positioning a biaxially
oriented plastic material which is stretchable along two axes.
7. A method of forming a carpeted plastic part comprising:
positioning a carpet between first and second mold halves, wherein
the carpet has a back surface; positioning a non-reinforced plastic
strip between the first and second mold halves; forming a hollow
parison of reinforced plastic material between the first and second
mold halves; and closing the first and second mold halves together
to form a carpeted plastic part having a thinned-down region of the
reinforced plastic material adjacent the plastic strip such that
the thinned-down region, the plastic strip, and the carpet form a
flexible living hinge.
8. The method of clam 7, further comprising heating said plastic
strip prior to said step of positioning the plastic strip adjacent
a portion of the carpet.
9. The method of claim 7, further comprising adhesively securing
the plastic strip to the carpet.
10. The method of claim 7, wherein said step of positioning a
non-reinforced plastic strip comprises positioning a biaxially
oriented plastic material which is stretchable along two axes.
11. The method of claim 7, wherein said step of positioning a
non-reinforced plastic strip comprises positioning a polypropylene
strip having a thickness of approximately 0.5 mm.
12. The method of claim 7, wherein the non-reinforced plastic strip
is positioned between the carpet and the hollow parison.
13. The method of claim 7, wherein the hollow parison is positioned
between the non-reinforced plastic strip and the carpet.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation-in-part of U.S.
application Ser. No. 09/344,774, filed Jun. 28, 1999.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a blow-molded plastic part
having a non-reinforced plastic strip integrally molded therein to
form a durable living hinge.
[0004] 2. Background Art
[0005] Plastic components sometimes require significant
load-bearing characteristics, such as in vehicle load floors and
the like. In order to provide these load-bearing characteristics
the plastic material may be reinforced by glass filling for
example. However, this filling may also render the part brittle and
not suitable for a living hinge.
[0006] It is also sometimes desirable to provide an integral hinge
in the reinforced plastic component to allow respective bending of
adjacent portions of the plastic component, for example to form a
pivotable door for access to a spare tire storage compartment or
the like. Because reinforced materials are so brittle, a living
hinge typically cannot be formed in the material to allow pivoting,
therefore metal hinges have been used in such applications.
However, metal hinges result in significant material and labor
costs. It is therefore desirable to provide a method of forming a
reinforced plastic part with a hinge in which manufacturing costs
are reduced.
SUMMARY OF THE INVENTION
[0007] The present invention provides a method of manufacturing a
reinforced plastic part, such as a glass-filled plastic part,
wherein a living hinge is formed by integrally molding an unfilled
plastic strip in the part to form the living hinge.
[0008] More specifically, the present invention provides a method
of forming a carpeted plastic part wherein a carpet is positioned
between first and second mold halves. A non-reinforced plastic
strip is positioned adjacent a portion of the back surface of the
carpet. A hollow parison of reinforced plastic material is
positioned between the first and second mold halves. The first and
second mold halves are closed together to form a carpeted plastic
part having a thinned-down region of the reinforced plastic
material adjacent the plastic strip such that the plastic strip is
sandwiched between the thinned-down region and the carpet to form a
flexible living hinge.
[0009] Preferably, the non-glass-filled plastic strip is a
biaxially oriented plastic material which is stretchable along two
axes, such as a polypropylene material.
[0010] The present invention could be used for forming a living
hinge in any stiff material, such as a glass-filled plastic,
mica-filled plastic, talc-filled plastic or other structurally
reinforced plastic material.
[0011] The non-reinforced plastic strip may be positioned between
the carpet and the parison, or it may be positioned on the opposite
side of the parison from the carpet.
[0012] Accordingly, an object of the invention is to provide a
method of forming a durable living hinge in a load-bearing plastic
component.
[0013] A further object of the invention is to provide a method of
forming a durable living hinge in a carpeted load-bearing plastic
part, such as a vehicle load floor, in a manner in which
manufacturing costs are reduced.
[0014] The above objects and other objects, features and advantages
of the present invention are readily apparent from the following
detailed description of the best mode for carrying out the
invention when taken in connection with the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 shows an exploded side elevational view of the mold,
parison, plastic strip and carpet in accordance with the present
invention;
[0016] FIG. 2 shows a partial vertical cross-section of the
assembly of FIG. 1 with the mold halves closing together;
[0017] FIG. 3 shows a partial vertical cross-sectional view of a
molded part in accordance with the present invention;
[0018] FIG. 4 shows an exploded side elevational view of the mold,
parison, plastic strip and carpet in accordance with an alternative
embodiment of the invention;
[0019] FIG. 5 shows a partial vertical cross-section of the
assembly of FIG. 4 with the mold halves closing together; and
[0020] FIG. 6 shows a partial vertical cross-sectional view of a
molded part in accordance with the embodiment of FIGS. 4 and 5.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0021] The present invention is particularly useful, for example,
in forming carpeted vehicle load floors, which require significant
load-bearing characteristics. However, the present invention would
also be useful in forming a living hinge in any reinforced plastic
component. The term "reinforced" as used herein refers to a plastic
component which is glass-filled, mica-filled, talc-filled or
otherwise reinforced for added strength.
[0022] The present invention is described with reference to FIGS.
1-3. As shown, a carpet 10 is positioned between first and second
mold halves 12,14. It is commonly known to integrally mold carpet
components with plastic parts, such as for vehicle interior
components, including doors, load floors, etc.
[0023] A non-reinforced plastic strip 16 is positioned adjacent a
portion of the back surface 18 of the carpet 10. In a preferred
embodiment, the plastic strip 16 is a polypropylene material. Such
a material is biaxially oriented such that it is stretchable along
two axes, thereby enabling it to act as a durable living hinge.
Prior to closing the first and second mold halves 12,14 together,
the plastic strip 16 may be adhesively secured to the back surface
18 of the carpet 10 to hold the plastic strip 16 in position before
the mold halves 12,14 are closed together.
[0024] A hollow parison 20 of glass-filled plastic material is
positioned between the first and second mold halves 12,14. The
parison 20 is a hollow extruded tube of hot, pliable material which
is expanded by pressurized air within the tube. This method is
commonly known in the art for forming hollow plastic parts.
[0025] It is preferable to heat the plastic strip 16 prior to the
closing of the mold halves 12,14 to enhance bonding of the plastic
strip 16 with the material of the parison 20. For example, with a
polypropylene plastic strip 16, it is preferable to heat the
polypropylene to approximately 300.degree. F. prior to closing the
first and second mold halves 12,14 together to enhance bonding with
the parison material 20. Improper bonding of the plastic strip 16
with the parison material will limit useful life of the living
hinge.
[0026] As shown in FIG. 2, the first and second mold halves 12,14
are then closed together to force the parison 20, plastic strip 16
and carpet 10 together. The mold halves 12,14 are held together
until the molded part has assumed the desired shape and cooled.
[0027] As shown in FIG. 3, the closing of the mold halves 12,14
together against the parison 20 forms a thin-downed region 22 of
the glass-filled material 20 immediately adjacent the plastic strip
16. In this area of the thinned-down portion 22, the carpet 10,
plastic strip 16 and thinned-down portion 22 form the flexible
living hinge 24.
[0028] In this configuration, the body of the glass-filled material
20 forms a structurally rigid load-bearing component while the
living hinge 24 enables pivotal movement of adjacent portions of
the load-bearing component, such as for a spare tire storage door,
or the like.
[0029] Because the plastic strip 16 is a biaxially oriented plastic
material, such as a polypropylene or other non-reinforced plastic,
the material is stretchable along two axes. Those materials which
are oriented along a single axis will tend to break after a few
cycles, whereas the biaxially oriented materials are much more
durable for bending. The thinned-down portion 22 will likely break
after a few cycles, but the plastic strip will remain in tact and
operative as the living hinge.
[0030] A further advantage of the invention is that the entire
assembly is recyclable with the elimination of the metal hinge.
[0031] FIGS. 4-6 illustrate an alternative embodiment of the
invention wherein the non-reinforced plastic strip 16' is
positioned between the parison 20 and the mold half 12, as opposed
to being positioned between the parison 20 and carpet 18. As shown,
similarly to the embodiment described above with reference to FIGS.
1-3, the non-reinforced plastic strip 16' is compressed against the
hollow parison 20 and the carpet 10 to form the final assembly
shown in FIG. 6 in which the non-reinforced plastic strip 16'
cooperates with the thinned down portion 24 of the hollow parison
20 and the carpet 10 to form a flexible hinge for the carpet
10.
[0032] While the best mode for carrying out the invention has been
described in detail, those familiar with the art to which this
invention relates will recognize various alternative designs and
embodiments for practicing the invention within the scope of the
appended claims.
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