U.S. patent application number 15/590328 was filed with the patent office on 2017-08-24 for reinforced blow moulded vehicle running board and method of making same.
This patent application is currently assigned to METELIX PRODUCTS INC.. The applicant listed for this patent is METELIX PRODUCTS INC.. Invention is credited to Tim CHAPMAN, Roger ELGNER.
Application Number | 20170239872 15/590328 |
Document ID | / |
Family ID | 49670588 |
Filed Date | 2017-08-24 |
United States Patent
Application |
20170239872 |
Kind Code |
A1 |
CHAPMAN; Tim ; et
al. |
August 24, 2017 |
Reinforced Blow Moulded Vehicle Running Board and Method of Making
Same
Abstract
A structurally reinforced blow moulded assembly includes an
overmould body bonded to one or more preformed internal stiffening
ribs. The reinforcing r ribs are partially encapsulated by o the
overmould body in an orientation selected to carry load a forces
thereon. The resin mixture used to form the overmould body
comprises 10% to 40% by weight short glass having a length less
about 15 cm, and 60% to 90% by weight thermoplastic resin. To
facilitate recycling the reinforcing ribs comprise 30 to 60% by
weight long glass fibers and 40% to 70% of thermoplastic bonding
resin.
Inventors: |
CHAPMAN; Tim; (Etobicoke,
CA) ; ELGNER; Roger; (Toronto, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
METELIX PRODUCTS INC. |
Etobicoke |
|
CA |
|
|
Assignee: |
METELIX PRODUCTS INC.
|
Family ID: |
49670588 |
Appl. No.: |
15/590328 |
Filed: |
May 9, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13902918 |
May 27, 2013 |
9676338 |
|
|
15590328 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B29C 2049/4882 20130101;
B29C 2049/2013 20130101; B29C 2049/2017 20130101; B29C 49/04
20130101; B60N 2/68 20130101; B60R 3/002 20130101; Y10T 428/237
20150115; B29C 49/20 20130101; B60R 19/03 20130101; B29C 2049/2086
20130101 |
International
Class: |
B29C 49/20 20060101
B29C049/20; B60R 19/03 20060101 B60R019/03; B60R 3/00 20060101
B60R003/00 |
Claims
1. A method of manufacturing a structurally reinforced blow moulded
assembly, the blow moulded assembly comprising, an overmould member
having a sidewall, the overmould member comprising between 10% by
weight to 30% by weight short glass fibers having a longitudinal
length of less than 10 cm, and 70% by weight to 90% by weight of a
thermoplastic base resin, and a longitudinally elongated
reinforcing rib insert at least partially encapsulated within said
sidewall, said reinforcing rib insert having at least one flange
member comprising 40% by weight to 70% by weight long glass fibers
having a length of greater than 25 cm up to a length corresponding
to a longitudinal length of said reinforcing rib insert, and 30% by
weight to about 60% by weight of a bonding resin, said method
comprising the steps of, drawing said long glass fibers co-mingled
with said bonding resin through a pultrusion mould to at least
partially heat fuse the co-mingled fibers to form a reinforced rib
blank having at least one reinforced core, cutting the reinforced
rib blank to a desired longitudinal length of the reinforcing rib
insert, positioning the reinforcing rib insert at least partially
in an overmould mould, and blow moulding the overmould member over
the reinforcing rib insert.
2. The method as claimed in claim 1, wherein the reinforcing rib
insert includes a forward said flange member, a rearward said
flange member and a longitudinally extending connecting web joining
the forward flange member and the rearward flange member, and
wherein during said drawing step, melt injection moulding
additional bonding resin about the melt fused co-mingled fibers to
form the connecting web.
3. The method as claimed in claim 2, wherein at least one of the
forward flange member, the rearward flange member and the
reinforcing web includes a bonding layer and/or one or more
longitudinally extending melt fingers, and wherein said step of
injecting additional said bonding resin comprises melt injection
moulding said additional bonding resin about the at least one
reinforced core to form said bonding layer and/or melt fingers.
4. The method of claim 1, wherein the step of drawing the long
glass fibers comprises drawing spooled polypropylene glass threads
through the pultrusion mould.
5. The method as claimed in claim 1, wherein the step of at least
partially heat fusing the co-mingled fibers comprises compacting
and heating the co-mingled fibers to a temperature about a
decomposition temperature of the bonding resin to heat fuse the
fibers in a generally parallel arrangement.
6. The method of claim 5, wherein said long glass fibers are
twisted, pre-wound and/or braided prior to compacting and
heating.
7. The method as claimed in claim 1, wherein the blow moulded
assembly comprises a vehicle part selected from the group
consisting of a vehicle running board, a vehicle seat back, a
vehicle load floor and a vehicle bumper beam, the overmould mould
comprising a blow mould having a plurality of mould platens, and
said step of positioning the reinforcing rib insert comprises
positioning the reinforcing rib insert in a first said mould
platen, and after positioning the reinforcing rib insert, blow
moulding the overmould member.
8. The method of claim 7, wherein said step of blow moulding the
overmould member includes, melt extruding a parison into the blow
mould comprising a short fiber/base resin mixture comprising 10% to
30% by weight said short glass fibers and 70% to 90% by weight said
thermoplastic resin, and blow moulding the parison over the
reinforcing rib insert to form the overmould member at least
partially melt bonded to the reinforcing rib insert.
9. The method as claimed in claim 8 wherein said step of
positioning said reinforcing rib insert further comprises securing
said reinforcing rib insert in said first mould platen by vacuum
suction.
10. The method as claimed in claim 8, wherein the short glass
fibers have a longitudinal length selected at less than about 1
cm.
11. The method as claimed in claim 8, wherein the thermoplastic
resin comprises polyethylene, polypropylene or ABS.
12. A method of manufacturing a structurally reinforced blow
moulded vehicle part, the vehicle part comprising, an overmould
body having a sidewall defining a hollow interior, a forward
surface and rear surface spaced from the forward surface, the
overmould body further comprising between about 10% by weight to
30% by weight short glass fibers, and about 70% by weight to 90% by
weight of a thermoplastic resin, wherein said short glass fibers
have a longitudinal length of less than about 10 cm, and a
longitudinally elongated reinforcing rib reinforcing said forward
surface against a rearward load force, the reinforcing rib having a
longitudinally extending forward portion, a longitudinally
extending rearward flange member having a rearward bearing surface,
and a connecting web joining the forward portion to the rearward
flange, said method comprising, drawing long glass fibers having a
length greater than about 25 cm co-mingled with a bonding resin
through a pultrusion mould to melt bond said co-mingled fibers as
part of a reinforced rib blank, the reinforced rib blank comprising
40% by weight to 70% by weight of said long glass fibers, and 30%
by weight to about 60% by weight of said bonding resin, cutting
said reinforcing rib from said reinforcing rib blank, positioning
the reinforcing rib at least partially in a blow mould, and blow
moulding the overmould member over the reinforcing rib in the blow
mould, whereby said reinforcing rib is at least partially
encapsulated by said sidewall with the longitudinally extending
forward position in substantially bearing contact with at least a
portion of said sidewall defining the forward surface, and the
rearward bearing surface disposed in a generally coplanar
orientation with said rear surface.
13. The method of claim 12, wherein during said drawing step, melt
injecting additional bonding resin about said melt bonded
co-mingled fibers.
14. The method as claimed in claim 12, wherein at least one of the
forward portion, the rearward flange member and the connecting web
includes a bonding layer and/or one or more longitudinally
extending melt fingers, and wherein said step of injecting
additional bonding resin comprises melt injection moulding said
additional bonding resins about bonded generally parallel arranged
co-mingled fibers to form said bonding layer and/or melt
fingers.
15. The method of claim 13, wherein the step of drawing the long
glass fibers comprises drawing spooled polypropylene glass threads
impregnated with said bonding resin through the pultrusion
mould.
16. The method as claimed in claim 12, wherein the blow mould
comprises a plurality of mould platens, and said step of
positioning the reinforcing rib comprises securing the reinforcing
rib in a first said mould platen under vacuum, and thereafter blow
moulding the overmould member over the reinforcing rib to at least
partially melt bond to the reinforcing rib insert.
17. The method as claimed in claim 16, wherein vehicle part is
selected from the group consisting of a vehicle running board, a
vehicle seat back, a vehicle load floor and a vehicle bumper beam,
and said thermoplastic and said bonding resin are each selected
from the group consisting of polypropylene, ABS and
polyethylene.
18. A method of manufacturing a structurally reinforced moulded
assembly, the moulded assembly comprising, an overmould member
having a sidewall defining a hollow interior, a forward support
surface and a rear surface spaced from the support surface, the
overmould member comprising between 10% by weight to 30% by weight
short glass fiber having a longitudinal length of less than 10 cm,
and 70% by weight to 90% by weight of a thermoplastic base resin, a
longitudinally elongated reinforcing rib insert at least partially
encapsulated within said sidewall, said reinforcing rib insert
having a forward flange member, a rearward flange member spaced
from the forward flange member, and a longitudinal connecting web
joining the forward flange member to the rearward flange member,
said method comprising the steps of, drawing said long glass fibers
co-mingled with a bonding resin through a pultrusion mould to
effect melt fusing of the co-mingled fibers to form a reinforced
rib blank, said rib blank including said forward flange member,
said rearward flange member and said connecting web, wherein at
least one of said forward flange member and said rearward flange
member comprises 40% by weight to 70% by weight of said long glass
fibers, and 30% by weight to 60% by weight of said bonding resin,
having at least one reinforced core, cutting the reinforced rib
blank to a finished longitudinal length of the reinforcing rib
insert, whereby the long glass fibers of the reinforcing rib insert
have a longitudinal length of great than 25 cm up to the finished
longitudinal length of the reinforcing rib insert, positioning the
reinforcing rib insert at least partially in an overmould mould,
and blow moulding the overmould member over the reinforcing rib
insert, with an interior side of the forward support surface in
bearing contact with at least a portion of the forward flange
surface.
19. The method as claimed in claim 18, wherein during said drawing
step, melt injection moulding an additional amount of bonding resin
about the melt fused co-mingled fibers to form the connecting
web.
20. The method as claimed in claim 19, wherein the moulded assembly
comprises a blow moulded vehicle part selected from the group
consisting of a vehicle running board, a vehicle seat back, a
vehicle load floor, and a vehicle bumper beam, at least one of the
forward flange member, the rearward flange member and the
reinforcing web includes a bonding layer and/or one or more
longitudinally extending melt fingers, and wherein said step of
injecting additional said bonding resin comprises melt injection
moulding said additional bonding resin about the at least one
reinforced core to form said bonding layer and/or melt fingers.
21. The method of claim 20, wherein the step of drawing the long
glass fibers comprises drawing spooled polypropylene glass threads
through the pultrusion mould.
22. The method of claim 19, wherein said step of moulding the
overmould member comprises, positioning the reinforcing rib insert
in a blow mould, melt extruding a parison into the blow mould
comprising a short fiber/base resin mixture comprising 10% to 30%
by weight said short glass fibers and 70% to 90% by weight said
thermoplastic resin, and blow moulding the parison over the
reinforcing rib insert to form the overmould member at least
partially over and melt bonded to the reinforcing rib insert, with
the rearward flange member generally coplanar with the rear
surface.
23. The method as claimed in claim 22, further comprises securing
said reinforcing rib insert in said blow mould by vacuum suction.
Description
RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 13/902,918, filed May 27, 2013. This
application claims the benefit of 35 USC .sctn.119(e) to U.S.
Provisional Patent Application Ser. No. 61/653576, filed May 31,
2012.
SCOPE OF THE INVENTION
[0002] The present invention relates to reinforced blow moulded
articles, more preferably blow moulded vehicle parts such as
running boards, seat backs, load floors and bumper beams which are
provided with one or more internal stiffening or reinforcing ribs
to provide structural reinforcement. More preferably the articles
are provided with one or more fiber-reinforced plastic stiffening
ribs formed having a composition which is complementary to that of
a blow moulded plastic overmould body to facilitate the reuse and
recycling of waste flash and/or rejected articles by regrinding and
re-melt, as part of a thermoplastic base resin used overmould
production.
BACKGROUND OF THE INVENTION
[0003] The manufacture of blow moulded articles for use as vehicle
parts is known. In the case of larger vehicle parts which are
provided for either structural applications, or which, as a result
of design requirements, are required to provide bend or deformation
resistance, conventionally one or more rib-like reinforcing webs
are moulded directly into the part sidewall.
[0004] FIG. 1 shows a cutaway perspective bottom view of a prior
art blow moulded running board 10 produced in accordance with
conventional manufacturing processes. The running board 10 is
formed by blow moulding a thermoplastic resin parison in a mould
having a desired overall elongated shape. After moulding, the
running board 10 is formed having a generally hollow interior 100
which is delineated by a moulded resin sidewall 12, and which
defines generally parallel spaced and longitudinally extending
upper tread and bottom surfaces 18,20 which are joined to each
other along the respective front and rear sides by forward and rear
side webs 22,24.
[0005] As shown in FIG. 1, the bottom surface 20 of the running
board 10 is adapted for mounting at its end and mid-portions,
against three or more L-shaped steel brackets (brackets 28a,28b
shown), which in turn are secured directly to a side of a vehicle
frame (not shown). To facilitate proper positioning and mounting,
the bottom surface 20 may include a series of moulded spaced
recesses 30. Each recess 30 is moulded directly into the sidewall
12 and is sized for alignment and juxtaposed engagement with an
associated bracket 28, respectively.
[0006] The sidewall 12 further defines a series of longitudinally
aligned V-shaped reinforcing webs 32 formed in the bottom surface
20, and which extend between the recesses 30. As shown in the
cutaway view, the reinforcing webs 32 are formed with an upwardly
tapering V-shape and terminate at an uppermost bight immediately
adjacent to the underside 18a of the upper tread surface 18. The
taper angle of the V-shape of the reinforcing webs 32 is chosen to
prevent the running board 10 from binding within the mould
following its formation, and facilitate its removal therefrom after
moulding operation.
[0007] The inventors have appreciated that conventional prior art
running boards 10 suffer various disadvantageous. In particular, as
a result of their angular geometry, the V-shaped reinforcing webs
32 achieve less structural reinforcement than, for example, a
planar I beam or vertical-web reinforcement designs. In addition,
as a result of mould limitations, it is not possible to provide
reinforcing structures between the running board upper tread
surface 18 and the moulded bracket recesses 30. As a result,
conventional blow moulded running boards 10 suffer the disadvantage
that in their design, unreinforced weakness points exist which
could result in premature deformation and/or part failure in the
event of loading.
SUMMARY OF THE INVENTION
[0008] To at least partially overcome some of the difficulties
associated with prior art designs, the present invention provides a
structurally reinforced blow moulded article or assembly. The
assembly includes an overmould member or body which is formed from
a glass fiber or graphite reinforced thermoplastic base resin
mixture, and which is bonded to and/or at least partially
encapsulates one or more preformed internal stiffening or
reinforcing inserts or ribs. The reinforcing inserts or ribs
(hereinafter collectively referred to as ribs) are preferably at
least partially encapsulated by and/or melt fused to the overmould
member by blow moulding in an orientation selected to at least
partially carry load and/or impact forces thereon.
[0009] The base resin mixture used in the formation of the
overmould member preferably comprises between about 10% to 40% by
weight short glass, polycarbonate and/or graphite fibers having a
length less than about 15 cm, and about 60% to about 90% by weight
thermoplastic resin. To facilitate the recycling and reuse of not
only waste flash, but more preferably also damaged or defective
finished parts, the reinforcing ribs preferably comprise between
about 30 to 70% by weight long glass or graphite fibers having
longitudinal length greater than about 25 cm, preferably greater
than 50 cm, and most preferably which extend the entire
longitudinal rib length; and about 30% by weight to 70% by weight
of thermoplastic bonding resin.
[0010] The applicant has appreciated that with the foregoing
overmould and rib compositions, both waste flash, as well as any
defective ribs and/or finished products advantageously may be
reground and blended for re-use as part of thermoplastic base
resin/short fiber mixture in the blow moulding of subsequent
overmould parts, minimizing manufacturing waste. Most preferably,
the overmould body is formed by blow moulding a resin mixture
comprising between about 20% to 30% by weight short glass fibers
and 70% to 80% by weight of a thermoplastic base resin selected
from polyethylene, polypropylene, and/or acrylonitrile butadiene
styrene (ABS). Other thermoplastics and/or thermoplastic resins may
however be used, depending upon the completed article and/or its
intended application.
[0011] The short glass fibers preferably have a longitudinal length
selected at less than about 10 cm, preferably less than about 1 cm,
and most preferably less than about 0.5 cm.
[0012] Although not essential, in a preferred construction the
bonding resin used in the formation of the rib is the same as, or
complimentary to, the base resin used in the formation of the
overmould body.
[0013] It is envisioned that the reinforced assembly may be used
for the manufacture of a variety of different types of blow moulded
articles. In one preferred application, the reinforced assembly is
produced as a vehicle part, and which may include by way of
non-limiting example a vehicle running board, a seat back, a
vehicle load floor, and/or a vehicle bumper beam. The assembly is,
however, applicable to the manufacture of other vehicle parts and
classes of reinforced blow moulded articles.
[0014] Although not essential, in one preferred configuration, the
reinforcing rib is provided with a generally I-beam shaped profile,
having a pair of spaced lateral flanges joined by a longitudinally
extending connecting web. The rib preferably has a lateral width of
between about 0.5 to 1 cm and is provided with an upper edge which
follows the general contour of a forward or top surface of the
overmoulded body to be reinforced. Most preferably, the rib has a
height selected to extend forwardly in a general perpendicular
orientation from a rear surface of the overmould body to engagedly
support the underside of the forward surface.
[0015] Other rib profiles, however, may also be used including
those with either a simple rectangular or L-shaped profiles.
[0016] In a most simplified construction the reinforcing rib may be
manufactured having a homogeneous internal composition. In an
alternate construction, to facilitate melt bonding with the
overmould body, the reinforcing rib may be formed having an
compound structure in which the connecting web is formed
substantially entirely of thermoplastic resin, and one or both rib
flanges are formed having long glass fiber reinforced cores which
are at least partially coated with an outer thermoplastic resin
layer. Optionally, the stiffening rib may be further provided with
a series of longitudinally spaced radial projections, webs, bosses,
suitable barbs or other suitable fingers (hereinafter collectively
referred to as fingers). The fingers have a size selected to
facilitate their preferential melting during overmoulding
operations to enhance the anchoring and positioning of the rib and
its melt attachment to the overmould body.
[0017] Accordingly, in one aspect the present invention resides in
a structurally reinforced blow moulded assembly, the assembly
comprising, an overmould member, said overmould member having
sidewall defining a hollow interior, a forward support surface and
rear surface generally parallel to and spaced from the forward
support surface, the overmould member comprising between about 10%
by weight to 30% by weight short glass fibers, and about 70% by
weight to 90% by weight of a thermoplastic base resin, wherein said
short glass fibers having a longitudinal length selected at less
than about 10 cm, and preferably less than about 1 cm, at least one
longitudinally elongated reinforcing rib insert, said rib insert
being partially encapsulated by said sidewall including, a forward
flange member provided for bearing contact with an interior side of
said forward support surface, a rearward flange member spaced from
the forward flange member and providing a rearward bearing surface
generally coplanar with said rear surface, and a longitudinal
extending connecting web joining the forward flange to the rearward
flange, each of the forward and rearward flanges comprising about
40% by weight to about 70% by weight long glass fibers, and about
30% by weight to about 60% by weight of a bonding resin, wherein
said long glass fibers have a longitudinal length greater than
about 25 cm, and preferably a length corresponding to a
longitudinal length of said rib.
[0018] More preferably, the reinforcing rib insert has a
longitudinal length greater than about 0.5 m, and preferably
greater than about 1.0 m, the connecting web has a lateral
thickness selected at less than about 3 mm, and preferably less
than about 1 mm, and the forward flange member and the rearward
flange member have a maximum lateral width selected at between
about 0.5 cm and 4 cm, and preferably between about 0.75 cm and 2.5
cm.
[0019] In another aspect, the present invention resides in a
structurally reinforced vehicle part, the vehicle part comprising,
an overmould body having sidewall defining a hollow interior, a
forward surface and rear surface spaced from the forward surface,
the overmould body comprising between about 10% by weight to 30% by
weight short glass fibers, and about 70% by weight to 90% by weight
of a thermoplastic resin, wherein said short glass fibers having a
longitudinal length selected at less than about 10 cm, a
longitudinally elongated reinforcing rib reinforcing said forward
surface against a rearward load force, the reinforcing rib at least
partially encapsulated by said sidewall and including, a
longitudinally extending forward flange member in substantially
bearing contact with a portion of said sidewall defining said
forward surface, a longitudinally extending rearward flange member
spaced from the forward flange member and having a rearward bearing
surface disposed in a generally coplanar orientation with said
rearsurface, and a longitudinal extending connecting web joining
the forward flange to the rearward flange, the reinforcing rib
comprising about 30% by weight to about 70% by weight, and
preferably upto 60% by weight long glass fibers having a
longitudinal length greater than about 50 cm, and preferably a
length corresponding to a longitudinal length of said rib, and
about 30% by weight to about 70% by weight, and preferably 40% to
70% by weight of said thermoplastic resin.
[0020] In a further aspect, the present invention reside in a
vehicle running board comprising: an overmould composite plastic
step, said step having a sidewall defining a hollow interior
portion, an upper support surface for supporting a user thereon,
and a lower mounting surface spaced from the upper support surface,
the step comprising between about 10% by weight short glass fibers
having a longitudinal length selected at less than about 15 cm, and
preferably less than about 1 cm, and about 70% by weight of a resin
selected from the group consisting of ABS, polyethylene, and
polypropylene, at least one reinforcing rib, said rib having an
elongated longitudinally length and comprising, an upper flange
member, a lower flange member, and a connecting web extending
between and joining said upper and lower flange members, each of
said upper and lower flange members comprising between about 40% by
weight to 70% by weight long glass fibers having a longitudinal
length greater than about 50 cm and preferably greater than about
100 cm, and about 30% by weight to about 60% by weight of said
resin, said upper flange member and connecting web being
substantially encapsulated within and retained by said sidewall,
with an upper portion of said upper flange member disposed
substantially adjacent to said upper support surface and a bottom
portion of said lower flange member in substantially co-planar
alignment with an adjacent portion of said rear surface, whereby
load forces on said forward support surface are at least partially
carried by said rib.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Reference may be had to the enclosed drawings together with
the following detailed description, in which:
[0022] FIG. 1 shows a partial cutaway perspective bottom view of a
conventional blow moulded vehicle running board in accordance with
the prior art;
[0023] FIG. 2 illustrates a perspective view of a blow moulded
vehicle running board in accordance with a first aspect of the
invention;
[0024] FIG. 3 shows a partially cut-away perspective bottom view of
the running board of FIG. 2 taken along lines 3-3', showing the
positioning of a reinforcing rib therein;
[0025] FIG. 4 shows a partial perspective view of the reinforcing
rib used in the running board of FIG. 2 in accordance with a first
embodiment of the invention;
[0026] FIG. 5 shows a cross-sectional view of a reinforcing rib for
use in the running board of FIG. 2 in accordance with a second
embodiment of the invention;
[0027] FIG. 6 shows schematically a moulding die used in the
pultrusion moulding of the reinforcing rib shown in FIG. 5;
[0028] FIGS. 7 to 9 illustrate schematically the positioning of the
reinforcing rib of FIG. 5 in a blow moulding die during blow
moulding encapsulation and fusion of the overmould running board
sidewall thereabout;
[0029] FIG. 10 provides a partial cross-sectional view of the
moulding die platen used in the blow moulding die shown in FIG. 7,
illustrating the securement of the reinforcing rib therein, prior
to the formation of the overmould sidewall; and
[0030] FIG. 11 shows a cross-sectional view of the blow mould
running board illustrating the partial and encapsulation of the
reinforcing rib by the overmould sidewall, immediately following
blow moulding operation.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0031] Reference may be had to FIG. 2 which illustrates a
thermoplastic glass fiber composite vehicle running board 50 which
is manufactured in accordance with a most preferred aspect of the
invention. The vehicle running board 50 is provided for mounting
against a pair of conventional L-shaped steel mounting brackets
28a,28b for securement along the side of a vehicle (not shown).
Depending on the application, the running board 50 has a typical
longitudinal length selected at between about 1 and 2 meters, and a
lateral step width of between about 10 and 20 cm. As will be
described, the vehicle running board 50 is formed having internal
structural reinforcement which provides the running board 50 with
sufficient structural integrity to enable its securement to the
vehicle using only the single pair of mounting brackets 28a,28b in
supporting the running board 50 towards each respective
longitudinal end, thereby reducing the running board installation
time.
[0032] As shown best in FIG. 3 the running board 50 has a generally
hollow open interior 100 and is formed having a binary construction
consisting of a fiber reinforced thermoplastic sidewall 52 which is
reinforced by a longitudinally extending fiber reinforced
thermoplastic reinforcing rib 54. As will be described to
manufacture the running board 50, the sidewall 52 is formed as a
blow moulded overmould which partially encapsulates, and is melt
bonded to the reinforcing rib 54 for enhanced structural rigidity.
As shown best in FIG. 3, the sidewall 52 defines the overall
running board profile. In this regard, the sidewall 52 delineates
an upper surface 60 which includes the running board upper tread
surface 62 for supporting a user thereon, a generally planar bottom
surface 64 which is spaced from the tread surface 62, and forward
and rearward connecting webs, 66,68 which merge with to join the
upper and bottom surfaces 60,64. As shown best in FIGS. 3 and 4,
the bottom surface 64 is formed having a pair of moulded recesses
72a,72b which are each spaced towards a respective running board
end 74a,74b. The recesses 72a,72b are sized to receive therein the
associated mounting bracket 28 in the securement of the running
board 50 along the side of the vehicle.
[0033] FIG. 3 shows best the stiffening rib 54 as positioned to
carry and transmit load forces on the sidewall 52 to the mounting
brackets 28a,28b. As will be described, the rib 54 is moulded
directly into the running board 50 itself, so as to extend in a
generally vertical orientation along its longitudinal mid-axis.
[0034] The sidewall 52 and reinforcing rib 54 are both formed from
complimentary fiber/resin compositions which are selected to enable
waste flash, defective reinforcing ribs 52 and/or the entirety of
any blemished or defective running boards 50 to be recycled for
subsequent use in the manufacture of other thermoplastic blow
moulded articles.
[0035] Most preferably, the sidewall 52 is formed from a fiber
reinforced thermoplastic base resin mixture which contains from
about 10% by weight to about 30% by weight short glass fibers, and
about 70% by weight to about 90% by weight of a base resin of ABS,
polyethylene polypropylene or mixtures thereof. To facilitate blow
moulding, the short glass graphite andlor polycarbonate fibers
having a length of less than 1 cm, and more preferably less than
about 0.5 cm.
[0036] The reinforcing rib 54 is formed having an overall
composition which includes upto 50% by weight long glass graphite
and/or polycarbonate fibers, and at least 50% by weight of a
thermoplastic bonding resin. Although not essential, the long glass
fibers are preferably selected from glass fibers which are
comingled with a bonding resin, such as ABS, polyethylene,
polypropylene or mixtures thereof, and which are heat fused in a
generally parallel orientation. The long glass fibers 122 have a
longitudinal length of preferably at least about 25 cm, and more
preferably extend substantially the entire longitudinal length of
the rib 54. For maximum recyclability, the bonding resin is most
preferably is chosen the same as the base resin used in the
formation of the sidewall 52 The applicant has appreciated that
providing the reinforcing rib 54 having the aforementioned
composition advantageously allows for simplified recycling and
repurposing of defective or blemished ribs 54 and running boards
50. In particular, blemished or defective running boards 50 may be
reground, and the reground material thereafter re-mixed into the
base resin mixture for use in the blow moulding of sidewalls in the
manufacture of a subsequent running board 50, and/or in the
manufacture of further articles and parts.
[0037] FIG. 4 illustrates a partial perspective view of the
reinforcing rib 54 in accordance with a first embodiment of the
invention. The reinforcing rib 54 is provided with an elongated
longitudinal length which extends substantially the longitudinal
length of the running board 50. The rib 54 is provided with a pair
of laterally extending spaced upper and lower flanges 76,78. The
flanges 76 extend the longitudinal length of the rib 54 and are
joined by a connecting web 80. The vertical height between the
flanges 76,78 is selected such that following the encapsulation of
the rib 54 by the sidewall 52, any load forces on the upper tread
surface 62 along the entire length of the running board 50 are
transmitted to and carried by the rib 54 onto the mounting brackets
28.
[0038] In the embodiment shown, the upper and lower flanges 76,78
are provided with a partially rounded cross-sectional profile. The
applicant has appreciated that the rounded flange shape of the
flanges 76,78 advantageously facilitate pultrusion moulding of the
reinforcing rib 54. Most preferably, the upper flange 76 has a
generally round cross-sectional profile having an approximate
radially diameter selected at between about 1 and 2 cm. The lower
flange 78 is formed having a flattened triangular cross-sectional
profile. The lower flange 78 provides the rib 54 with a generally
planar bottom 84 having a lateral width selected at between about 2
and 4 cm for dispensing load forces thereon, and which tapers
upwardly to merge with the connecting web 80.
[0039] In the construction shown, the connecting web 80 has a
lateral thickness selected at less than about 5 mm, preferably less
than about 3 mm, and most preferably about 1 mm. Depending upon the
size of the running board 50, the web 80 is formed having the
vertical dimension between the flanges 76,78 selected at between
about 0.3 and 1.5 cm. It is to be appreciated, however, that
connecting webs of different dimensions may be used, depending upon
the article of manufacture.
[0040] Although not essential, in a most preferred construction the
reinforcing rib 54 is provided having a compound construction in
which the upper and lower flanges 76,78 are provided respectively
with a long fiber reinforced core, 86,88 which are each in turn
further encapsulated by an outermost bonding layer 90. Preferably,
each of the long fiber reinforced cores 86,88 are themselves
composed of 40% by weight to about 70% by weight of the long glass
fibers, and about 30% by weight to about 60% by weight of the
bonding resin, and wherein the bonding resin is used to effect the
melt fusion of the long glass fibers to each other in a generally
parallel strand orientation. Although not essential, preferably the
connecting web 80 is formed so as to consist entirely of bonding
resin. The bonding layer 90 most preferably is also formed entirely
of the bonding resin, to better facilitate the partial melt bonding
and fusion with the sidewall 52 during overmoulding.
[0041] As shown best in FIG. 7, the reinforcing rib 54 is provided
with a pair of cutouts 94a,94b. Each cutout 94 is sized and spaced
for alignment with a corresponding recess 72a,72b. The cutouts 94
have a dimension selected such that in final assembly, the upper
flange 76 of the rib 54 locates immediately adjacent to the
underside of the upper tread surface 62 and the bottom 84 of the
lower flange 78 in a substantially coplanar alignment with the
adjacent portions of the bottom surface 64. So positioned, the
upper flange 76 and connecting web 80 provides reinforcement to the
running board 50 at each of the recesses 72a,72b. The extension of
the cutout portions of the rib 54 over the recesses 72a,72b thus
minimizes any points of weakness along the longitudinal length of
the running board 50. Once vertically positioned, the stiffening
rib 54 thus provides added structural support by transmitting load
forces placed on the tread surface 62 directly and evenly through
the running board 54, to the bottom surface 84.
[0042] Reference may be had to FIG. 5 which illustrates a
pultrusion formed connecting rib 54 for use with the running board
50 in accordance with a further embodiment of the invention, and
wherein like numerals are used to identify like components. In the
rib 54 shown in FIG. 5, the portion of the bonding layer 90 in
which defines the outermost perimeter of the upper flange 76 and
connecting web 80 is further provided with a series of
longitudinally extending melt fingers 96. The melt fingers 96
extend radially outwardly a distance of between about 0.5 and 1 mm,
and have a thickness selected to preferentially melt and heat fuse
with the sidewall 52 during overmoulding operation. The applicant
has appreciated that the provision of the melt fingers 96
advantageously provide enhanced melt bonding between the
reinforcing rib 54 and sidewall 52, to more securely fix the rib 54
against movement relative thereto.
[0043] FIG. 6 shows schematically the manufacture of the
reinforcing rib 54 shown in FIG. 5 by pultrusion moulding in
accordance with a preferred method. FIG. 6 illustrates a pultrusion
mould 110 which includes a pair of primary mould cavities 112,114
which are used to preform the long fiber reinforced cores 86,88
respectively, and a capstock feed inlet 116 which provides fluid
communication with the secondary mould cavity 120 which is
downstream from the primary cavities 112,114, and which is used
from the finished rib profile. The capstock feed inlet 116 is used
for the melt injection of bonding resin to form the outer bonding
layer 90 and connecting web 80 about the heat bonded glass fiber
cores 86,88.
[0044] As shown in FIG. 6, with the pultrusion mould 110, initially
long glass fibers which have been co-mingled with the bonding resin
are drawn into the primary mould cavities 112,114. Initially,
parallel strands of thermoplastic co-mingled glass fibers are
compacted and heated in each mould cavity 112,114 the mould at a
temperature slightly above the resin decomposition temperature, to
fuse the fibers and form reinforced cores 86,88 having the desired
profile.
[0045] After partial melt fusing of the co-mingled fibers as the
reinforced cores 86,88, the formed cores 86,88 drawn into the
secondary mould cavity 120 where the bonding resin is melt injected
via the capstock feed inlet 116 to form the bonding layer 90,
connecting web 80 and melt fingers 96.
[0046] In one simplified form of manufacture, the stiffening rib 54
is formed by pultrusion by drawing polypropylene glass spooled
threads through the pultrusion mould 110, while impregnating with a
structural plastic bonding resin to form a finished rib blank 54'.
The blank 54' is then cut to the desired longitudinal rib length,
having regard to the length of the finished running board 50, and
the cutouts 94a,94b are formed in a single stamping. The resulting
formed , rib 54 is provided with melt fused glass fibers which have
an axially length which extend the entire length of the rib 54, and
which have a continuous length selected at between about 200 cm to
250 cm.
[0047] While in a preferred method of manufacture, the elongated
glass fibers are drawn through the mould 110 so as to heat fuse to
each other in a generally parallel arrangement, it is to be
appreciated that in other constructions, the long glass fibers 122
may be pre-wound, braided, and/or twisted prior to being drawn into
the mould 110. Similarly, while pultrusion provides various
advantages in manufacture, it is to be appreciated that in
alternate modes of manufacture, the rib 54 could also be formed by
compression or injection moulding.
[0048] In a most preferred sidewall construction, the upper surface
60, bottom surface 64 and side webs 66,68 are integrally formed
from a plastic/short fiber base resin parison mixture, consisting
of polypropylene or ABS, and 10 to 30% glass fibers which have an
average length of between about 0.1 cm and 0.5 cm. It is envisioned
that the base resin mixture used to form the running board sidewall
52 includes both virgin and re-ground components including waste
flash, as well as reground rejected pieces. The sidewall 52 is
formed as an overmould body which is blow moulded over a preformed
reinforcing rib 54 to substantially encapsulate and bond
therewith.
[0049] FIGS. 7 to 9 show best a two-part mould 130 used in the
final manufacture of the running board 50 shown in FIG. 2. The
mould 130 includes bottom and top mould platens 132,134. The bottom
platen 132 is used to form the running board bottom surface 64,
recesses 72a,72b and part of the connecting webs 66,68. The top
platen 134 is used to form the upper surface 60 including the upper
tread surface 62, as well as part of the connecting webs 66,68.
[0050] FIGS. 7 and 11 show best, the bottom platen 132 as being
provided with a longitudinally elongated vacuum channel 136. The
channel 136 is formed having a flat bottom sized to receive therein
in juxtaposed contact the bottom 84 of the reinforcing rib 54. The
vacuum channel 136 is further provided with a series of
longitudinally spaced vacuum manifold apertures 140 which are
fluidically coupled by associated vacuum lines 142 (FIG. 10) to a
negative pressure source (not shown). The apertures 140 are spaced
along the bottom of the channel 136 at locations selected whereby
the activation of the vacuum source effects a sufficient negative
pressure to releasably secure a reinforcing rib 54 to the bottom
platen 132, with the bottom 84 of the lower flange 78 in
juxtaposition within the vacuum channel 136.
[0051] To form the running board 50, a preformed reinforcing rib 54
is initially positioned in the platen 132 in a generally vertical
orientation with its bottom 84 positioned in the vacuum channel
136. The vacuum source is actuated, drawing air through the
apertures 140 via the associated vacuum lines 142, maintaining the
rib 54 in the desired orientation during blow moulding operations.
With the rib 54 so secured, the mould 130 is activated to hot
extrude a parison 144 of melted base resin between the top and
bottom platens 132,134. With the parison 144 hot extruded
therebetween, the platens 132,134 are thereafter move together in
the direction of arrows 200 closing the mould cavity. The heated
parison 144 is thereafter stretched into the desired shape to form
the sidewall 52 by blow moulding, encapsulating the stiffening rib
54 in the manner shown in FIG. 11. During stretching of the parison
144, the melt fingers 96 are contacted and partially melted and
fuse bonded to the blown moulded plastic sidewall 52. The heat
fusing of the blown plastic sidewall 52 with the melt fingers 96
further anchors the rib 54 in the desired vertical orientation
within the interior of the running board 50.
[0052] Because the exposed rib bottom 84 and bottom surface 64 of
the formed running board 50 is substantially flat, the formed part
may be easily removed from the lower mould bottom platen 132 with
minimum concern of die lock.
[0053] Because the formed running board 50 is made entirely with a
glass reinforced plastic structure, any excess flash produced in
moulding operations, as well as waste rib material or even entire
rejected parts may be re-ground and re-melted for use in subsequent
part manufacture. The current invention thus advantageously
provides a more economical, waste-resistant manufacturing
process.
[0054] In another possible construction, the rib 54 may be provided
with one or more through-bores (not shown) in addition to or in
place of the melt fingers 96. Such through-bores are sized to allow
for the penetration of the blow moulded plastic therethrough, to
facilitate stabilization and anchoring of the rib 54 within the
running board interior 100.
[0055] Although the foregoing description describes the manufacture
of a reinforced blow moulded running board 50 having a single
stiffening rib 54, the invention is not so limited. It is to be
appreciated that the running board 50 could be provided with
multiple stiffening ribs 54 at lateral and/or longitudinally
arranged orientations. In addition, the process of the present
invention may be used in the manufacture of a variety of other
types of blow moulded components and article for both vehicle and
non-vehicle applications, with the result that the foregoing
detailed description should not be viewed as limiting.
[0056] While the detailed description describes the rib 54 as
having an upper flange 76 with a rounded-cross section profile, and
a lower flange 78 having a generally triangular profile, the
invention is not so limited. It is to be appreciated that depending
upon the application and the load forces to be carried, the
reinforcing rib 54 may be provided with a number of different
profiles. In one alternate, non-limiting embodiment, both the upper
and lower flanges 76,78 could be provided as generally planar
lateral projections. In an alternate possible design, the
reinforcing rib 54 may be formed having an L-shaped profile. Other
rib profile designs are also possible will now become apparent.
[0057] While the detailed description describes and illustrates
various preferred embodiments, the invention is not so limited.
Many modifications and variations will now occur to a person
skilled in the art. For a definition of the invention, reference
may be had to the appended claims.
* * * * *