Note: Descriptions are shown in the official language in which they were submitted.
CA 02523281 2007-11-07
VEHICLE STEP TUBE
BACKGROUND OF THE INVENTION
The present invention relates to step tubes for vehicles and to a method for
making step tubes.
Step tubes, which are substitutes for running boards, are commonly mounted on
vehicles for assisting a user of the vehicle to climb into and out of the
vehicle. They are also
commonly used for aesthetic reasons, and to protect the side of the vehicle.
Step tubes can be fabricated from aluminum extrusions. An example of such a
step tube is disclosed in U.S. Patent 6,588,782 to Coomber. The Coomber step
tube includes an
elongated support portion 100, multiple cap portions 200, a step pad 300, and
a mounting bracket
400. The cap portions 200 and the step portion 300 attach to the support
portion 100 to form an
upper surface of the assembly that is aesthetically pleasing and functional
for assisting vehicle
users. The step portion 300 may include a name plate 962, a plurality of
perforations 964 to
allow passage of light through the step pad 300, and a plurality of ridges 972
to provide traction
for users stepping on the step portion 300.
The Coomber step tube requires a considerable fabrication and assembly of
multiple extruded components. Consequently, manufacture of the Coomber step
tube requires
significant labor and therefore expense.
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SUMMARY OF THE INVENTION
The present invention provides a step tube for attachment to a vehicle
comprising one-piece, unitary elongated member having a generally uniform
cross-section
throughout its length, said member including a plurality of upwardly extending
ribs, each said
rib having a height and a thickness, a majority of said ribs having a height
at least twice the
thickness, said ribs defining a plurality of channels between said ribs, said
ribs and said
channels together forming an exposed upper surface of the step tube.
In one embodiment, transition portions extend between the step portion and the
flanking portions. The height of the ribs gradually transitions from the high
height in the
flanking portions to the short height in the step portion.
In another embodiment, the ribs in the step portion include transverse cuts to
further enhance traction and aesthetics in the step portion. The cuts may be
located at spaced
intervals throughout the step portion.
In another embodiment, the ribs have a uniform height along the longitudinal
length of the extrusion. The ribs are spaced apart to define channels in
between the ribs along
the longitudinal length of the extrusion.
In yet another embodiment, the step tube may include a pair of end caps
attached to the ends of the extrusion and covering the ends of the extrusion.
The end caps
include a plurality of openings aligned with the channels in the extrusion to
allow air and fluid
flow through the channels and the openings. The openings may be defined by a
plurality of
end cap ribs extending from the upper surface of the end caps.
The present invention also includes a method of manufacturing a step tube,
comprising the steps of a) extruding an elongated beam having a plurality of
vertically
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extending ribs and b) removing a portion of the ribs in a step portion of the
beam to define a
step platform. The removing step may be performed by a computer operated
machine.
The step tube of the present invention has a simplified unitary construction.
The vertically extending ribs minimize wear on the surface of the step tube,
and create
channels to receive dirt, snow, and ice below the step surface. The step tube
can be
manufactured more simply and with lower cost than prior step tubes. Therefore,
the step tube
provides advantages in manufacture and aesthetics without forfeiting function
or structure.
The invention of a first divisional application relates to a vehicle step tube
comprising a one-piece extrusion having a longitudinal length and an upper
surface, said
extrusion including a step portion and a pair of non-step portions flanking
said step portion,
and said extrusion including a plurality of exposed ribs extending upwardly
from said upper
surface along said length of said extrusion, said ribs having a second height
in said step
portion and a first height taller than said second height in said non-step
portions.
The invention of a second divisional application relates to a vehicle step
tube
comprising a one-piece elongated extrusion having a longitudinal length, an
outer surface, a
top portion defining a step area, and a side portion below said step area,
said side portion
defining a longitudinal slot opening through said outer surface and a trim
piece fitted within
said slot and located below said step area, said trim piece being for at least
one of decorating
and protecting said extrusion.
These advantages, and features of the invention will be more fully understood
and appreciated by reference to the description of the current embodiments and
the drawings.
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BRIEF DESCRIPTION OF THE DRAWINGS
Fig. I is an exploded view of the step tube and a vehicle body.
Fig. 2 is a perspective view of the step tube.
Fig. 3 is a perspective view of the step tube extrusion at section II in Fig.
1.
Fig. 4 is an end view of the extrusion of Fig. 2.
Fig. 5 is a perspective view of the extrusion at section II in Fig. 1,
including a
first cut.
Fig. 5A is a side view of the extrusion of Fig. 5.
Fig. 6 is a perspective view of the extrusion of Fig. 5, also including a
second
cut.
Fig. 6A is a side view of the extrusion of Fig. 6.
Fig. 7 is a perspective view of a second embodiment of the extrusion at
section II of Fig. 1.
Fig. 8 is an end view of the extrusion of Fig. 7.
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, +
Fig. 9 is a perspective view of the second embodiment of the extrusion at
section II in Fig. 1, including a first cut.
Fig. 9A is a side view of the extrusion of Fig. 9.
Fig. 10 is a perspective view of the extrusion of Fig. 9, also including a
second
cut.
Fig. 10A is a side view of the extrusion of Fig. 10.
Fig. 11 is a cross sectional view of the step tube attached to a bracket.
Fig. 12 is a bottom view of a mounting bracket attached to the extrusion.
Fig. 13 is a side view of an alternative embodiment.
Fig. 14 is a perspective view of the alternative embodiment of Fig. 13.
Fig. 15 is a perspective view of the extrusion including end caps according to
another alternative embodiment.
Fig. 16 is an exploded view of the extrusion and an end cap according to the
Fig. 15 embodiment.
Fig. 17 is an end view of the Fig. 15 embodiment.
Fig. 18 is a close up perspective view of the extrusion and an end cap
according to
the Fig. 15 embodiment.
Fig. 19 is a perspective view of the extrusion including end caps according to
another alternative embodiment.
Fig. 20 is an exploded view of the extrusion and an end cap according to the
Fig. 19 embodiment.
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DESCRIPTION OF THE CURRENT EMBODIMENTS
A step tube constructed in accordance with a preferred embodiment of the
present
invention is shown in Figs. 1 and 2 and generally designated 10. The step tube
10 generally
includes an elongated extrusion 12, having a plurality of generally vertical
ribs 14. The
extrusion further includes a step portion 16, transition portions 18, 20
flanking the step portion
16, and flanking portions 22, 24. The step tube is attached to a vehicle 26
with a plurality of
mounting brackets 28, and may include a pair of end caps 30.
As shown in Fig. 3, the extrusion 12 is an elongated beam. The extrusion may
be
comprised of aluminum, a similar alloy, a thermoplastic, or any other suitable
material. As the
beam 12 is extruded, it is cut to a desired length, depending on the vehicle
that it will be attached
to. As shown in Figs. 1 and 2, the beam 12 includes a step portion 16,
transition portions 18, 20
on either side of the step portion 16, and opposing flanking portions 22, 24
adjacent to the
transition portions 18, 20. Referring to Fig. 3, the beam 12 further includes
an upper surface 32,
a front surface 34, a rear surface 36, and a lower surface 38. The front
surface 34 preferably
includes a C-shaped slot 35 for receiving a trim piece 52 (shown in Fig. 11).
The lower 38 and
rear 36 surfaces preferably each include a T-shaped slot 39 for receiving
attachment brackets 28.
Referring now to Fig. 4, the plurality of ribs 14 extend vertically from the
upper
surface 32 of the extrusion 12. The ribs 14 are preferably spaced apart, and
each rib has a height
40, a base 42, and an outer edge 44. As shown, the height 40 of the ribs 14
may decrease in each
sequential rib 14 as the ribs 14 approach the front and rear surfaces 34, 36.
Alternatively, the
ribs 14 may have a uniform height 40.
As shown in Figs. 5 and 5A, the ribs 14 include a first cut 46 defining the
step
portion 16. In the illustrated embodiment, the step portion 16 is located in a
central section of
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the extrusion 12 (see Figs. 1 and 2). The first cut 46 is a cut that shaves
off a portion of the
height 40 of the ribs 14 such that the ribs 14 have a second height 48 in the
step portion 16. In
one embodiment, the first cut 46 is a machined cut. The second height 48 is
preferably uniform
from the front surface 34 to the rear surface 36 to form a level step
platform. In one
embodiment, the height 40 of the ribs 14 gradually tapers to the second height
48 within the
transition portions 18, 20. Alternatively, the transition portions 18, 20 may
have a variety of
desired shapes.
As shown in Figs. 6 and 6A, the ribs 14 also may include a second cut or
plurality
of cuts 50. The second cuts 50 preferably extend transversely through the ribs
14 across the
extrusion from the front surface 34 to the rear surface 36. The second cuts 50
are preferably
spaced apart in a series of cuts throughout the step portion 16 and the
transition portions 18, 20.
As shown in Fig. 6, the series of second cuts 50 may have a parabolic shape as
they extend
transversely across the extrusion 12. Alternatively, the second cuts 50 may
have a variety of
desired shapes and patterns. They may be straight cuts that are perpendicular
to the first cuts,
and they may even have the formation of a logo.
Referring to Figs. 1 and 11, the step tube may include a trim piece 52 and a
pair of
end caps 30. The trim piece 52 is a separate decorative part that may also be
extruded from
aluminum, a similar alloy, a thermoplastic, or other suitable material. It
also acts as a bumper to
protect the step tube 10. The trim piece 52 has a front surface 54 that is
shaped to correspond
with the shape of the front surface 34 of the extrusion 12, and a rear surface
56 that includes a T-
shaped protrusion 58 that may be slidably coupled with the C-shaped slot 35.
The end caps 30
are adapted to engage the open ends 58, 60 of the extrusion, and are shaped to
close off the ends.
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The end caps 30 may include a plurality of vertically extending extrusions to
correspond with the
ribs 14.
The step tube 10 may be attached to a vehicle body by a variety of
conventional
methods. Fig. 11 shows one such method, wherein at least one mounting bracket
28 is attached
at a first end 62 to the step tube 10 and at a second end 64 to a vehicle body
26. The first end 62
attaches to the T-shaped slots 39, with a nut 70 and bolt 72, or with a T-
shaped protrusion (not
shown) that may be slidably engaged with the slots 39. The second end 64
preferably attaches to
the vehicle 26 through slot 66 with a nut and bolt (not shown).
Figs. 7-10 show a second embodiment of the present invention, wherein the
extrusion 12 includes a web 21 that attaches between the outer edges 44 of the
ribs 14, and
encloses the ribs 14. As shown in Fig. 8, the profile of the extrusion 12 is
the same as the first
embodiment, but further including the web 21. Figs. 9 and 9A show the
extrusion 12 with the
web 21, further including a first cut 46. The cut 46 is identical to the first
cut 46 of the first
embodiment, however, in this embodiment, the first cut 46 removes a portion of
the web 21
along with portions of the ribs 14. The transition portions 18, 20 and the
step portion 16 are the
same as in the first embodiment. Fig. 10 additionally shows the second cut 15
as a series of cuts
identical to those of the first embodiment. The end portions 22, 24 continue
to include the web
21 after the cuts 46, 50 have been made.
Another embodiment of the invention is shown in Figs. 13 and 14. In this
embodiment, the step tube includes a plurality of step portions 16. As shown
in Figs. 13 and 14,
there are two step portions 16. The step portions 16 generally include first
and second cuts
similar to that disclose above. As shown, the second cuts 50 are perpendicular
to the first cuts
46. The cuts of each step portion 16 may vary in height and design. In
general, the multiple step
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portions coincide in location with front and rear doors of the vehicle and
possibly a cargo bed.
Of course, this embodiment may also include the web 21 of the second disclosed
embodiment.
In yet another embodiment, shown in Figs. 15-20, the step tube 10 does not
include the first cut 46 or the second cut 50. In this embodiment, the ribs 14
have a uniform
height. As shown, the ribs 14 have a uniform height 40 along the entire
longitudinal length of
the extrusion. The ribs 14 therefore define channels 80 that extend along the
length of the
extrusion in between the ribs 14. The outer edges 44 of the ribs 14 form a
surface for use as a
step platform along the length of the extrusion. The thickness of the ribs 14
may taper to a point
from the base 42 to the outer edge 44 in order to guide fluids away from the
surface.
Also in this embodiment, the step tube 10 may include alternative end caps
30'.
The end caps 30' are similar to the end caps 30, described above, in that they
are adapted to
engage the open ends 58, 60 of the extrusion, and are shaped to close off the
ends 58, 60. In this
embodiment, however, the end caps 30' include a plurality of openings 82 that
are aligned with
the channels 80 in the extrusion to allow fluids to flow through the channels
80 and the openings
82 and into an environment (i.e., out of the step tube). As shown, the end
caps 30' include an
upper surface 84, and a plurality of end cap ribs 86 extending upward from the
upper surface 84.
The end cap ribs 86 may be joined together by a web 94. The end cap ribs 86
align with the ribs
14 on the extrusion, so the openings 82 can align with the channels 80. As
illustrated, a plurality
of ribs 96 are included on a lower portion of the ends caps 30'. These ribs 96
are generally for
strength and aesthetics and do not require, nor typically include, openings
between them.
Additionally, the end caps 30' may include an opening 100 shaped to receive an
end 98 of the
trim piece 52. The opening 100 acts to retain the trim piece 52 in the C-
shaped slot 35. The end
caps 30' may attach to the extrusion in a variety of conventional ways,
including the fasteners 88
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extending through holes 90 in the end caps 30' and into receptacles 92 in the
extrusion. Figs. 19
and 20 show a variation of the Fig. 15 embodiment, wherein the extrusion
includes a web 21 as
described above. The end caps 30' attach to this extrusion in the same
conventional manner.
Manufacture of the present invention requires one or more of the steps of
a) extruding an elongated beam having a plurality of vertically extending
ribs; b) cutting down
the height of the ribs in a step portion of the beam to define a step
platform; and c) attaching the
beam to a vehicle body. The beam may be extruded such that it has the profile
shown in Fig. 4,
or alternatively the profile of Fig. 8. Step b) preferably includes the first
cut 46, followed by the
second cut(s) 50. The first and second cuts are preferably machined cuts that
are performed in an
automated process. Step c) may include attaching the beam to a vehicle with
the mounting
brackets 28, as shown in Figs. 1 and 11. The brackets are attached at a first
end 62 to the beam,
and at a second end 64 to the vehicle body 26. The trim piece 52 can be
slidably engaged in the
slot 35. The end caps 30 or 30' can be attached to the extrusion before it is
attached to the
vehicle body 26.
The above descriptions are those of current embodiments of the invention.
Various alterations and changes can be made without departing from the spirit
and broader
aspects of the invention, which are to be interpreted in accordance with the
principles of patent
law including the Doctrine of Equivalents.
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