U.S. patent application number 10/810752 was filed with the patent office on 2004-09-30 for drag reducing rotatable fairing usable on poles, posts and other structures.
Invention is credited to Gross, William.
Application Number | 20040187429 10/810752 |
Document ID | / |
Family ID | 32995008 |
Filed Date | 2004-09-30 |
United States Patent
Application |
20040187429 |
Kind Code |
A1 |
Gross, William |
September 30, 2004 |
Drag reducing rotatable fairing usable on poles, posts and other
structures
Abstract
In one aspect of the invention, a rotatable fairing apparatus
comprises a vertical support member anchored in a foundation and
subjected to an aerodynamic drag force. The rotatable fairing
apparatus further comprises a hollow elongate fairing sleeve that
covers at least a portion of the vertical support member. The
hollow elongate fairing sleeve is rotatably secured to the vertical
support member. Additionally, the hollow elongate sleeve has a
shape configured to reduce the aerodynamic drag force acting on the
vertical support member.
Inventors: |
Gross, William; (Pasadena,
CA) |
Correspondence
Address: |
KNOBBE MARTENS OLSON & BEAR LLP
2040 MAIN STREET
FOURTEENTH FLOOR
IRVINE
CA
92614
US
|
Family ID: |
32995008 |
Appl. No.: |
10/810752 |
Filed: |
March 26, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60459009 |
Mar 28, 2003 |
|
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Current U.S.
Class: |
52/831 ;
52/169.9 |
Current CPC
Class: |
E01F 9/623 20160201;
E04H 12/2292 20130101 |
Class at
Publication: |
052/720.1 ;
052/169.9 |
International
Class: |
E04H 009/14 |
Claims
What is claimed is:
1. A rotatable fairing apparatus comprising: a vertical support
member anchored in a foundation, wherein the vertical support
member is subjected to an aerodynamic drag force; and a hollow
elongate fairing sleeve covering at least a portion of the vertical
support member and rotatably secured to the vertical support
member, the hollow elongate sleeve having a shape configured to
reduce the aerodynamic drag force acting on the vertical support
member.
2. The rotatable fairing apparatus of claim 1, wherein the hollow
elongate fairing sleeve is rotatably secured to the vertical
support member by at least one bearing joint.
3. The rotatable fairing apparatus of claim 2, wherein the hollow
elongate fairing sleeve further comprises a first end, a second end
opposite the first end, and bearing joints positioned at the first
and second ends.
4. The rotatable fairing apparatus of claim 2, further comprising a
lateral support structure disposed on an interior side of the
hollow elongate fairing sleeve, the lateral support structure
comprising a plurality of bearings configured to facilitate
rotation of the hollow elongate fairing sleeve around the vertical
support structure during subjection of the aerodynamic drag
force.
5. The rotatable fairing apparatus of claim 1, wherein: the
vertical support member further comprises a tapered end structure;
and the hollow elongate fairing sleeve further comprises a cupped
support receptacle disposed within an interior side, the cupped
support receptacle configured to receive the tapered end
structure.
6. An apparatus comprising: an elongate support member; and an
elongate fairing sleeve having a first axis, the elongate fairing
sleeve covering at least a portion of the elongate support member,
configured to rotate around the elongate support member on the
elongate fairing sleeve first axis, and substantially shaped to
reduce an aerodynamic drag force acting on the elongate support
member.
7. The apparatus of claim 6, wherein: the elongate support member
further comprises a tapered end structure; and the elongate fairing
sleeve further comprises a cupped support receptacle disposed
within an interior side, the cupped support receptacle configured
to receive the tapered end structure.
8. The apparatus of claim 6, wherein the covered portion of the
elongate support member has an first aerodynamic drag coefficient
that is greater than a second aerodynamic drag coefficient of the
elongate fairing sleeve.
9. The apparatus of claim 6, wherein the elongate support member is
oriented vertically, and is anchored in a foundation structure.
10. The apparatus of claim 9, wherein the elongate fairing sleeve
has an upper end and a lower end opposite the upper end, such that
the lower end is displaced from the foundation structure by a first
height.
11. The apparatus of claim 10, further comprising a safety shield
attached to the elongate support member and displaced from the
foundation structure by a second height, such that the second
height is less than the first height.
12. The apparatus of claim 6, wherein the elongate support member
has a circular cross-sectional profile.
13. The apparatus of claim 6, wherein the elongate support member
has a rectangular cross-sectional profile.
14. The apparatus of claim 13, wherein the elongate support member
has a square cross-sectional profile.
15. The rotatable fairing apparatus of claim 6, wherein the hollow
elongate fairing sleeve is rotatably secured to the vertical
support member by at least one bearing joint.
16. The rotatable fairing apparatus of claim 15, wherein the hollow
elongate fairing sleeve further comprises a first end, a second end
opposite the first end, and bearing joints positioned at the first
and second ends.
17. The rotatable fairing apparatus of claim 15, further comprising
a lateral support structure disposed on an interior side of the
hollow elongate fairing sleeve, the lateral support structure
comprising a plurality of bearings configured to facilitate
rotation of the hollow elongate fairing sleeve around the vertical
support structure during subjection of the aerodynamic drag
force.
18. An apparatus comprising: an elongate support member; an
elongate fairing sleeve having a longitudinal axis and covering at
least a portion of the elongate support member; and means for
attaching the elongate support structure to the elongate fairing
device, such that the elongate fairing device can rotate around the
elongate support member on the elongate fairing sleeve longitudinal
axis.
19. The apparatus of claim 18, wherein the covered portion of the
elongate support member has an first aerodynamic drag coefficient
that is greater than a second aerodynamic drag coefficient of the
elongate fairing sleeve.
20. The apparatus of claim 18, wherein the elongate support member
has a rectangular cross-sectional profile.
21. The apparatus of claim 20, wherein the elongate support member
has a square cross-sectional profile.
22. The apparatus of claim 18, wherein the elongate support member
is oriented vertically, and is anchored in a foundation
structure.
23. The apparatus of claim 22, wherein the elongate fairing sleeve
has an upper end and a lower end opposite the upper end, such that
the lower end is displaced from the foundation structure by a first
height.
24. The apparatus of claim 23, further comprising a safety shield
attached to the elongate support member and displaced from the
foundation structure by a second height, such that the second
height is less than the first height.
25. An apparatus comprising: a first elongate support member; a
second elongate support member that is attached to the first
elongate support member; a first elongate fairing sleeve covering
at least a portion of the first elongate support member, and
configured to rotate around the first elongate support member; and
a second elongate fairing sleeve covering at least a portion of the
second elongate support member, and configured to rotate around the
second elongate support member.
26. A method comprising: providing an elongate object having a
first aerodynamic drag coefficient; and mounting a rotatable cover
having a second aerodynamic drag coefficient on the elongate
object, wherein the second aerodynamic drag coefficient is less
than the first aerodynamic drag coefficient.
27. The method of claim 26, further comprising orienting the
elongate object vertically, and anchoring the elongate object in a
foundation structure.
28. The method of claim 27, wherein the elongate object has an
upper end and a lower end opposite the upper end, such that the
lower end is displaced from the foundation structure by a first
height.
29. The method of claim 28, further comprising attaching a safety
shield to the elongate object such that the safety shield is
displaced from the foundation structure by a second height, wherein
the second height is less than the first height.
Description
PRIORITY APPLICATION
[0001] This application claims the benefit of U.S. Provisional
Patent Application No. 60/459,009, filed 28 Mar. 2003, the entire
disclosure of which is hereby incorporated by reference herein.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates generally to a rotatable
fairing configured to reduce aerodynamic drag forces on a
stationary object.
[0004] 2. Description of the Related Art
[0005] Objects placed in outdoor environments are often subjected
to a wide variety of adverse meteorological conditions, such as
extreme temperatures, heavy precipitation, and strong winds.
Although all of these conditions can be harmful, strong winds can
be especially damaging. In particular, not only can strong winds
directly damage an exposed object, such as by toppling or breaking
the object, but an object that has toppled or that has become
airborne can create a significant safety hazard. Therefore, while
winds can unquestionably damage large outdoor objects (for example,
skyscrapers or automobiles), smaller outdoor objects such as poles,
road signs, and raised light fixtures can be particularly dangerous
during a windstorm. Specifically, such smaller outdoor objects not
only can be directly damaged by the wind, but can also inflict
damage upon other people or objects if they topple or become
airborne.
[0006] Therefore, to minimize recurring maintenance costs and to
reduce the dangers associated with toppling or airborne debris
during windstorms, smaller outdoor objects such as poles, road
signs and raised light fixtures are generally designed to withstand
strong winds. However, conventional designs have necessitated the
use of heavy sidewalls and strong foundations to achieve strong
wind resistance. Heavy sidewalls and strong foundations are
expensive to construct, and can cause increased damage in the event
of structural failure.
SUMMARY OF THE INVENTION
[0007] Thus, it is desired to develop outdoor objects such as
poles, road signs and raised light fixtures that can withstand
strong winds without necessitating the use of heavy sidewalls and
strong foundations. Certain embodiments of the present invention
address these desires, advantageously allowing the weight and
expense of outdoor objects such as poles, road signs and raised
light fixtures to be reduced without sacrificing ability to
withstand strong winds. Specifically, placement of a rotatable
fairing on at least a portion of the pole, road sign or raised
light fixture reduces the aerodynamic drag force acting thereon,
thereby making the object able to withstand stronger winds.
[0008] In one aspect of the invention, a rotatable fairing
apparatus comprises a vertical support member anchored in a
foundation and subjected to an aerodynamic drag force. The
rotatable fairing apparatus further comprises a hollow elongate
fairing sleeve that covers at least a portion of the vertical
support member. The hollow elongate fairing sleeve is rotatably
secured to the vertical support member. Additionally, the hollow
elongate sleeve has a shape configured to reduce the aerodynamic
drag force acting on the vertical support member.
[0009] In another aspect of the invention, an apparatus comprises
an elongate support member and an elongate fairing sleeve. The
elongate fairing sleeve has a first axis, and covers at least a
portion of the elongate support member. Additionally, the elongate
fairing sleeve is configured to rotate around the elongate support
member on the elongate fairing sleeve first axis. The elongate
fairing sleeve is also substantially shaped to reduce an
aerodynamic drag force acting on the elongate support member.
[0010] In yet another aspect of the invention, an apparatus
comprises an elongate support member and an elongate fairing
sleeve. The elongate fairing sleeve has a longitudinal axis, and
covers at least a portion of the elongate support member. The
apparatus further comprises means for attaching the elongate
support structure to the elongate fairing device, such that the
elongate fairing device can rotate around the elongate support
member on the elongate fairing sleeve longitudinal axis.
[0011] In yet another aspect of the invention, an apparatus
comprises first and second elongate support members and first and
second elongate fairing sleeves. The first elongate support member
is attached to the second elongate support member. The first
elongate fairing sleeve covers at least a portion of the first
elongate support member, and is configured to rotate around the
first elongate support member. Likewise, the second elongate
fairing sleeve covers at least a portion of the second elongate
support member, and is configured to rotate around the second
elongate support member.
[0012] In still another aspect of the invention, a method comprises
providing an elongate object having a first aerodynamic drag
coefficient. The method further comprises mounting a rotatable
cover having a second aerodynamic drag coefficient on the elongate
object. The second aerodynamic drag coefficient is less than the
first aerodynamic drag coefficient.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Having thus summarized the general nature of the invention,
certain preferred embodiments and modifications thereof will become
apparent to those of ordinary skill in the art from the detailed
description herein having reference to the figures that follow.
[0014] FIG. 1 is an elevation view of a pole equipped with an
elongate rotatable fairing to reduce an aerodynamic drag force
acting on the pole.
[0015] FIG. 2 is a cross-sectional view of the pole illustrated in
FIG. 1 taken along line 2-2.
[0016] FIG. 3 is a cross-sectional view of the elongate rotatable
fairing illustrated in FIG. 1 taken along line 3-3.
[0017] FIG. 4 is an elevation view of a traffic signal equipped
with horizontal and vertical elongate rotatable fairings.
[0018] FIG. 5 is an elevation view of a pole equipped with an
elongate rotatable fairing and a safety shield.
[0019] FIG. 6 is a partial elevation view of a light fixture
illustrating a preferred means of rotatably securing an elongate
rotatable fairing to a pole.
[0020] FIG. 7 is a cross-sectional view of the light fixture
illustrated in FIG. 6 taken along line 7-7.
[0021] FIG. 8A is a cross-sectional view of the elongate rotatable
fairing of FIG. 6 taken along line 8-8.
[0022] FIG. 8B is a cross-sectional view of an elongate rotatable
fairing configured for use with a square support member.
[0023] FIG. 8C is a cross-sectional view of an alternative
embodiment of an elongate rotatable fairing.
[0024] FIG. 9 is an elevation view of a pole equipped to support an
elongate rotatable fairing at a pivot point.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0025] As discussed above, it is desired to develop outdoor objects
such as poles, road signs and raised light fixtures that can
withstand strong winds. However, it is also desired to construct
such outdoor objects without necessitating the use of heavy
sidewalls and strong foundations. Certain embodiments of the
present invention described herein address these desires,
advantageously allowing the weight and expense of outdoor objects
such as poles, road signs and raised light fixtures to be reduced
without sacrificing ability to withstand strong winds. In
particular, placement of a rotatable fairing on at least a portion
of the object reduces the aerodynamic drag force acting thereon,
thereby making the object able to withstand stronger winds.
[0026] FIG. 1 illustrates a pole 100 anchored in the ground 102 at
a foundation 104. The presence of any wind around the pole 100 will
cause an aerodynamic drag force {right arrow over (F)}.sub.p to act
on the pole 100. Therefore, if the pole 100 is placed in an outdoor
environment, it will often be subject to the aerodynamic drag force
{right arrow over (F)}.sub.p. The magnitude of the aerodynamic drag
force {right arrow over (F)}.sub.p depends on, among other things,
the velocity of the wind, the cross-sectional area of the pole 100,
the shape of the pole 100, and the drag coefficient Cd. The drag
coefficient C.sub.d is given by the following expression: 1 C d = 4
D r A v 2 ,
[0027] wherein D is the drag, r is the density of air, A is the
reference area, and v is the velocity of the wind. FIG. 2 is a
cross-sectional view of the pole 100 subject to aerodynamic drag
force {right arrow over (F)}.sub.p.
[0028] Still referring to the embodiment illustrated in FIG. 1, the
pole 100 is at least partially covered by an elongate rotatable
fairing 110. The elongate rotatable fairing 110 is optionally
displaced from the ground by a height h. As shown in the
cross-section illustrated in FIG. 3, the elongate rotatable fairing
110 has a streamlined shape that is preferably configured to reduce
the aerodynamic drag force {right arrow over (F)}.sub.p acting upon
the pole 100. Examples of such streamlined shapes include a
teardrop shape or an airfoil shape, although other shapes may also
be used to reduce the aerodynamic drag force {right arrow over
(F)}.sub.p acting upon the pole 100.
[0029] Therefore, in the regions of the pole 100 covered by the
elongate rotatable fairing 110, a reduced aerodynamic drag force
{right arrow over (F)}.sub.f acts on the elongate rotatable fairing
110. Because the elongate rotatable fairing 110 is freely
rotatable, the aerodynamic drag force {right arrow over (F)}.sub.p
can be reduced regardless of the direction of the wind. In a
preferred embodiment, the elongate rotatable fairing 110 comprises
a lightweight material such as a plastic, although in alternative
embodiments, other materials may be used, such as rubber, aluminum
or fabric. Such materials permit the pole 100 to withstand strong
aerodynamic drag forces at lower cost, and using lighter materials,
than would otherwise be possible using conventional design
techniques.
[0030] Although the pole 100 illustrated in FIG. 1 supports a light
fixture 120, one of ordinary skill in the art will recognize that
the elongate rotatable fairing 110 can be used in conjunction with
an unlimited variety of other outdoor objects, such as sign posts,
traffic signals, stakes, and horizontal members. For example, FIG.
4 illustrates a traffic signal assembly 130 having a horizontal
support member 132 and a vertical support member 134, each at least
partially covered by an elongate rotatable fairing 110.
Furthermore, one of ordinary skill in the art will recognize that
the support members that are at least partially surrounded by an
elongate rotatable fairing 110 need not have a cylindrical cross
section, but can also have other cross-sectional shapes, such as
ovals, rectangles or other polygons.
[0031] In certain embodiments, such as illustrated in FIG. 5, a
stationary safety shield 140 is positioned below the elongate
rotatable fairing 110. In one preferred embodiment, the stationary
safety shield 140 comprises a cylindrical disk. In such
embodiments, the stationary safety shield 140 is configured to
prevent the elongate rotatable fairing 110 from striking objects
placed below the elongate rotatable fairing 110. Specifically, if
the wind direction changes abruptly, the elongate rotatable fairing
110 may rotate suddenly, creating the risk of collision with an
object having a height greater than h, such as a bystander's head.
The presence of stationary safety shield 140 reduces the risk of
such collision.
[0032] FIGS. 6 and 7 illustrate a preferred technique for rotatably
attaching the elongate rotatable fairing 110 to the pole 100. In
such embodiments, a stationary support plate 150 is secured to the
pole 100 at the height h at which the elongate rotatable fairing
110 is to be rotatably attached to the pole 100. Preferably, a
plurality of ball bearings 152 are disposed around the
circumference of the stationary support plate 150. An elongate
rotatable fairing 110 equipped with a lower closed end plate 112 is
then positioned atop the stationary support plate 150, such that
the lower closed end plate 112 rests on the plurality of ball
bearings 152. In such embodiments, the elongate rotatable fairing
110 can freely rotate around the pole 100 on the ball bearings 152.
Furthermore, the weight of the elongate rotatable fairing 110 is
supported by the stationary support plate 150.
[0033] FIG. 8A illustrates a cross-sectional view of a preferred
embodiment of the elongate rotatable fairing 110 shown in FIG. 6
taken along line 8-8. In such embodiments, the elongate rotatable
fairing 110 further comprises a plurality of optional interior
support members 114. Interior support members 114 preferably
prevent the elongate rotatable fairing 110 from buckling or
otherwise being distorted when subjected to large aerodynamic drag
forces {right arrow over (F)}.sub.f. Additionally, FIG. 8A
illustrates that in certain embodiments, a gap 116 exists between
the pole 100 and an interior surface 118 of the elongate rotatable
fairing 110. In such embodiments, gap 116 is preferably filled with
a lubricant to reduce friction between the interior surface 118 of
the elongate rotatable fairing 110 and the pole 100.
[0034] FIG. 8B illustrates that the elongate rotatable fairing 110
can be used in embodiments in which the pole 100 has a non-circular
cross-sectional shape. In such embodiments, at least a portion of
the covered portion of the pole 100 is fitted with a stationary
circular adapter 119. Preferably, the stationary circular adapter
119 has a diameter that is less than the diameter of the interior
surface 118 of the elongate rotatable fairing 110. In such
embodiments, the elongate rotatable fairing 110 can freely rotate
around the pole 100, despite the fact that the pole 110 has a
non-circular cross-sectional shape.
[0035] FIG. 8C is a cross-sectional illustration of an alternative
embodiment of an elongate rotatable fairing 110. In such
embodiments, the elongate rotatable fairing 110 further comprises a
plurality of internal guides 160. Each of the internal guides 160
preferably comprises a series of ball bearings configured to rotate
along the surface of the pole 100. This configuration preferably
prevents the elongate rotatable fairing 110 from buckling or
otherwise being distorted when subjected to large aerodynamic drag
forces {right arrow over (F)}.sub.f. Additionally, the presence of
the internal guides 160 further promotes free rotation of the
elongate rotatable fairing 110 around the pole 100.
[0036] FIG. 9 illustrates another technique for rotatably securing
the elongate rotatable fairing 110 to the pole 100. In such
embodiments, the elongate rotatable fairing 110 preferably further
comprises an upper closed end plate 113. This configuration allows
the elongate rotatable fairing 110 to be slid over the pole 100,
which preferably comprises a pivot point 106. Thus, the pivot point
supports the interior side of the upper closed end plate 113,
thereby allowing the elongate rotatable fairing 110 to rotate
around the pole 100. In other embodiments, the interior side of the
upper closed end plate 113 further comprises a cupped support
receptacle configured to receive the pivot point 106 of the pole
100. Such embodiments allow the elongate rotatable fairing 100 to
rotate around the pole 100 with reduced frictional losses.
[0037] One of ordinary skill in the art will recognize that other
suitable means of rotatably securing the elongate rotatable fairing
110 to the pole 100 exist. Such means include, but are not limited
to, bearing joints and sliding joints. Such alternative means of
rotatable attachments are fully compatible with the rotatable
fairing described herein.
[0038] The various embodiments described herein permit outdoor
objects such as poles, signs and raised light fixtures to withstand
strong aerodynamic drag forces. Specifically, covering at least a
portion of such objects with an elongate rotatable fairing reduces
the aerodynamic force acting upon such objects. This allows such
objects to be manufactured at lower cost, and using lighter
materials, than would otherwise be possible using conventional
design techniques. Additionally, reduction of the aerodynamic drag
force acting on such objects increases the safety of such objects
by reducing the likelihood of such objects toppling or becoming
airborne.
[0039] The above presents a description of various preferred
embodiments of a rotatable fairing, and of the manner and process
of making and using it, in such full, clear, concise and exact
terms as to enable any person skilled in the art to which it
pertains to make and use such a rotatable fairing. This rotatable
fairing is, however, susceptible to modifications and alternate
constructions from that discussed above which are fully equivalent.
Consequently, it is not the intention to limit this rotatable
fairing to the particular embodiments disclosed. On the contrary,
the intention is to cover all modifications and alternate
constructions coming within the spirit and scope of the rotatable
fairing as generally expressed by the following claims, which
particularly point out and distinctly claim the subject matter of
the rotatable fairing.
* * * * *