U.S. patent number RE34,551 [Application Number 07/886,230] was granted by the patent office on 1994-02-22 for ducted fan.
This patent grant is currently assigned to Vornado Air Circulation Systems, Inc.. Invention is credited to Michael C. Coup, Glen W. Ediger, Gary P. Israel, Donald J. Moore.
United States Patent |
RE34,551 |
Coup , et al. |
February 22, 1994 |
Ducted fan
Abstract
A ducted fan including a funnel-shaped duct positioned upstream
of the impeller and connected to a base, an outer cowling
concentrically positioned downstream and attached to said duct
through a series of ribs, an inner cowling positioned inside the
outer cowling and surrounding the impeller and a circular grill
attached to the discharge end of the inner cowling. The grill
including a center hub and a series of arcuate-shaped ribs
extending outwardly from the hub and having a constant curvature of
less diameter than the outside radius of the grill whereby the
maximum lateral spacing between the ribs is at a radius inboard
from the outside radius of the grill.
Inventors: |
Coup; Michael C. (Wichita,
KS), Israel; Gary P. (Wichita, KS), Ediger; Glen W.
(Newton, KS), Moore; Donald J. (Wichita, KS) |
Assignee: |
Vornado Air Circulation Systems,
Inc. (Wichita, KS)
|
Family
ID: |
23134924 |
Appl.
No.: |
07/886,230 |
Filed: |
May 21, 1992 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
Reissue of: |
294780 |
Jan 9, 1989 |
04927324 |
May 22, 1990 |
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Current U.S.
Class: |
415/121.2;
415/181; 415/211.2; 416/247R; 416/63 |
Current CPC
Class: |
F04D
29/703 (20130101); F04D 25/08 (20130101) |
Current International
Class: |
F04D
29/00 (20060101); F04D 25/08 (20060101); F04D
25/02 (20060101); F04D 29/70 (20060101); F04D
029/70 () |
Field of
Search: |
;416/247R,246,63,17C
;415/121.2,181,119,189,190,208.1,208.2,209.2,211.2 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Kwon; John T.
Attorney, Agent or Firm: Cushman, Darby & Cushman
Claims
Having described the invention with sufficient clarity to enable
those familiar with the art to construct and use it, we claim:
1. A ducted fan comprising:
a base member with a motor and bladed impeller attached to the
base;
a funnel-shaped duct with its large end facing upstream
concentrically positioned upstream of the blades and around the
motor and connected thereto;
an outer cowling concentrically positioned, connected to the
funnel-shaped duct through a series of radial ribs;
a inner cowling positioned inside the outer cowling and attached
thereto, the inner cowling being circular in lateral cross section
and tapered longitudinally in shape from its larger diameter intake
end to its lesser diameter discharge end;
a circular grill having an outer radius attached to the discharge
end of the inner cowling, the grill including a center hub and a
series of arcuate shaped ribs extending outwardly from the hub to
said outer radius, each rib having a constant curvature radius and
each rib being equally spaced from each other around the hub, the
maximum lateral spacing between the ribs is inboard from said outer
radius; and
a support means pivotally attached to said motor and base
member.
2. A ducted fan as set forth in claim 1, wherein the ribs of the
grill each have a center of curvature which locus of points lies on
a circle concentric with the grill at approximately one-half the
outer radius of the grill.
3. A ducted fan as set forth in claim 1, wherein the ribs of the
grill each have a center of curvature which locus of points lies on
a circle concentric with the grill at approximately one-half the
outer radius of the grill and the hub has a radius of approximately
one-fifth the outer radius of the grill.
4. A ducted fan as a set forth in claim 1, wherein the ribs of the
grill have a radius approximately two-thirds the outer radius of
the grill with the center of curvature point of each rib lying on a
circle concentric with the grill having a radius approximately
one-half the outer radius of the grill.
5. A ducted fan as set forth in claim 1, wherein the ribs of the
grill each have a center of curvature which locus of points lies on
a circle concentric with the grill at approximately one-half the
outer radius of the grill and the lateral cross section of each rib
has an airfoil shape with its leading edge facing the fan
blades.
6. A ducted fan as set forth in claim 1, including multiple tab
means positioned around the periphery of the inner cowling's intake
end which deflect in and engage the upstream edge of the outer
cowling which when all of the tab means are deflected allows
separation of the inner cowling and grill from the fan.
7. A ducted fan as set forth in claim 1, including four hook-shaped
tab means positioned around the periphery of the inner cowling
intake end which deflect in and engage the outer cowling at its
upstream edge, which requires two or more manual operations before
the inner cowling can be separated from the fan.
8. A ducted fan as set forth in claim 1, wherein the support means
is a single tubular metal leg formed to provide a curved floor
engaging portion and horizontal mounting portion which engages the
base member and electrical wires from the motor which pass through
the tubular leg.
9. A ducted fan as set forth in claim 1, wherein the support means
is a single tubular metal leg formed to provide a floor-engaging
portion and a horizontal mounting portion which engages the base, a
preloaded spring means surrounding the horizontal mounting portion
of said leg which engages the motor and said metal leg, to provide
a spring force to counter balance the offset weight of the fan and
mounting brackets which rotatably attach the horizontal mounting
portions of said leg to the base, permitting the fan to rotated on
tits support means.
10. A ducted fan as set forth in claim 1, wherein the support means
is a single tubular metal leg formed to provide a floor-engaging
portion and a horizontal mounting portion which engages the base, a
preloaded spring means surrounding the horizontal mounting portion
of said leg which engages the motor and said metal leg, to provide
a spring force to counter balance the offset weight of the fan and
mounting brackets which rotatably attach the horizontal mounting
portion of said leg to the base permitting the fan to be rotated on
its support means, and spring stop means attached to the horizontal
mounting portion of said leg comprising an offset tab which engages
an end of said spring means preventing the spring from rotating
around said leg.
11. A ducted fan comprising:
a base member with a motor and bladed impeller attached to the base
which blades rotate in one direction;
a funnel-shaped duct with its large end facing upstream
concentrically positioned upstream of the blades and around the
motor and connected thereto;
an outer cowling concentrically positioned, connected to the
funnel-shaped duct through a series of radial ribs;
a inner cowling positioned inside the outer cowling and attached
thereto, the inner cowling being circular in lateral cross section
and tapered longitudinally in shape from its larger diameter intake
end to its lesser diameter discharge end;
a circular grill having an outer radius attached to the discharge
end of the inner cowling, the grill including a center hub and a
series of arcuate shaped ribs extending outwardly from the hub and
curving in the opposite direction of rotation from said blades to
said outer radius, and each rib being equally spaced from each
other around the hub, the maximum lateral spacing between the ribs
is inboard from said outer radius; and
a support means pivotally attached to said motor and base
member.
12. A ducted fan as set forth in claim 11, wherein the lateral
spacing between the ribs of the grill is no greater than 0.5
inches.
13. A ducted fan as set forth in claim 11, wherein the outer
cowling has a convex outer surface with a rounded upstream edge
which together with the inner cowling at its intake end forms an
aerodynamically clean rounded leading edge.
14. A ducted fan as set forth in claim 11, wherein the outer
cowling has a convex outer surface with a rounded upstream edge
which together with the inner cowling at its intake end forms an
aerodynamically clean rounded leading edge and between the
downstream edge of the outer cowling and the inner cowling is an
annular cavity which provides a handle for lifting the fan.
15. A ducted fan comprising:
a base member with a motor and bladed impeller attached to the
base;
a funnel-shaped duct with its large end facing upstream
concentrically positioned upstream of the blades and around the
motor and connected thereto;
an outer cowling concentrically positioned connected to the
funnel-shaped duct through a series of radial ribs;
a removable inner cowling positioned inside the outer cowling and
releasably attached thereto, the inner cowling being circular in
lateral cross section and tapered longitudinally in shape from its
larger diameter intake end to its lesser diameter discharge
end;
a circular grill having an outer radius attached to the discharge
end of the inner cowling, the grill including a center hub and a
series of arcuate shaped ribs extending outwardly from the hub to
said outer radius, and
a support means pivotally attached to said motor and base member.
.Iadd.16. A ducted fan as in claim 15 wherein said outer cowling
extends axially toward the discharge end of the inner cowling and
is spaced radially outwardly therefrom. .Iaddend. .Iadd.17. A
ducted fan as in claim 15 wherein the arcuate shaped ribs have a
continuous curvature. .Iaddend.
.Iadd.18. A ducted fan as in claim 15 wherein the funnel shaped
duct extends generally axially toward the blades from the series of
radial ribs. .Iaddend. .Iadd.19. A ducted fan as in claim 15
wherein said outer cowling connects together and rigidifies one set
of ends of the series of radial ribs. .Iaddend. .Iadd.20. A ducted
fan as in claim 15 wherein the curvature of said arcuate shaped
ribs is in the opposite direction of rotation from that of said
bladed impeller. .Iaddend. .Iadd.21. A ducted fan comprised of a
base member including a motor and a bladed propeller operatively
attached thereto, an entry duct concentrically positioned upstream
of the bladed propeller and connected to said base member, an outer
member concentrically positioned relative to and connected to said
entry duct so as to be spaced therefrom, duct means for enclosing
the bladed propeller and having a portion removably connected to
allow access
to the interior of said ducted fan. .Iaddend. .Iadd.22. A ducted
fan comprised of a base member including a motor and a bladed
propeller operatively attached thereof, an entry duct
concentrically positioned upstream of the bladed propeller and
connected to said base member, an outer member concentrically
positioned relative to and spaced from said entry duct by a series
of radially extending ribs, a removable inner member having a
portion thereof positioned inside the outer member and releasably
attached thereto, the inner member being generally circular in
lateral cross-section and terminating at a discharge end, and a
grill member having an outer radius attached to the discharge end
of said inner member. .Iaddend. .Iadd.23. A ducted fan as in claim
22 wherein said removable inner member is positioned and spaced
radially within said outer member. .Iaddend. .Iadd.24. A ducted fan
as in claim 22 wherein said outer member surrounds at least a
portion of said inner member. .Iaddend.
Description
BACKGROUND OF THE INVENTION
The present invention is an improved design of the ducted fan set
forth in U.S. Pat. Nos. 2,554,602, 2,554,600 and 2,554,601.
The general concept of providing ducted fans with a multiplicity of
concentrically spaced cone-shaped ducts in their intakes to
increase the air output of the fan has been well known for many
decades as typified in U.S. Pat. Nos. 2,287,822 and 2,330,907.
Having a ducted fan with multiple cones co-axially spaced in
telescoping relation not only provides an increased output at a
given power use but also functions as a safety grill in conjunction
with the connecting ribs. The outer cowling also can function as a
bumper housing to deflect and absorb energy when the fan falls or
impacts a stationary object.
All of the above-mentioned patents illustrate fans which could not
be sold today by reason of the large grill openings on the front
and back of the fans. Current OSHA requirements require consumer
fans to have grills with a maximum lateral opening of one-half
inch.
It is therefore the principal object of the present invention to
provide a new and improved front grill and duct structure which
increases the fan's capacity and efficiency while decreasing its
sound over the prior art grills or no grills at all.
Another object of the present invention is to provide a new and
improved ducted fan wherein the front grill and the inner cowling
are integral and are easily removable by deflecting four separate
tabs positioned around the periphery of the outer cowling.
Another object of the invention is to provide a new and improved
single leg support for the fan which allows the fan to pivotally
turn on the support while a preloaded spring counteracts the offset
weight of the fan and retains it in place. The support leg also is
a conduit for the wires which supply the motor.
Further advantages and features of the invention are set forth in
the following detailed description and accompanying drawings which
embody the present invention.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side elevational view of the fan in longitudinal
section;
FIG. 2 is a front view of the fan normal to the grill;
FIG. 3 is a front perspective view of the fan;
FIG. 4 is a rear perspective view of the fan;
FIG. 5 is a partial plan view of the fan grill to an enlarged
scale;
FIG. 6 is a sectional view to an enlarged scale taken along line
6--6 of FIG. 5;
FIG. 7 is a partial sectional view to an enlarged scale of the
inner and outer cowling;
FIG. 8 is a sectional view to an enlarged scale taken along line
8--8 of FIG. 9; and
FIG. 9 is a plan view of the fan base and its support leg with the
cover plate removed.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The drawings illustrate a ducted blade-type fan which is generally
referred to by reference numeral 10. The fan 10 is mounted on a
tubular support leg 12. The leg 12 includes a curved floor-engaging
portion 14 and a short horizontal mounting portion 16 to which the
fan base 32 is rotatably attached. Support leg 2 is fabricated from
steel tubing and bent to its particular shape by commonly-known
tube-bending techniques. Support leg 12 also functions as a conduit
for the electrical wires 18 from motor 20 which enter leg 12 at its
upper end, as seen in FIG. 9, and exit the leg 2 at its lower end
22.
Fan motor 20 carries an impeller blade 24 on its drive shaft which
includes three blades 26, 28 and 30. Fan motor 20 is concentrically
bolted to base member 32 by four bolts 34. Base member 32 is a
plastic injection molded part formed at the same time with duct 62
and outer cowling 68, later described in detail. Formed on base 32
are a series of motor-mounting pads 36. Attaching the support leg
12 to the fan base 32 are a pair of u-shaped straps 38 which urge
leg portion 16 against an arcuate-shaped saddle 40 molded in base
member 32, as best seen in FIG. 8.
Positioned around leg portion 16, as seen in FIGS. 8 and 9, is a
coil spring 42 having straight end sections 44 and 46. End section
44 is restrained from movement around the support leg by a small
offset tab 48 which is spotwelded to tube 16. The amount of
rotating friction between tube 16, saddle 40, and the straps 38 can
be determined by tightening nuts 50 on bolts 34. Coil spring 42
when installed, has a preload force acting on motor 20, as best
seen in FIG. 8, which urges the motor in a clockwise direction.
This preload from spring 42 will offset the weight-created moment
from the fan and its ducts attempting to rotate the fan 10 in a
counterclockwise direction, as seen in FIG. 1. Also positioned on
bolts 34 are a pair of rubber mounts 52 which have the ends of
mounting straps 38 sandwiched therebetween.
Base member 32 includes a peripheral ridge 54 which supports a
cover plate 56. The cover plate has a matching retention groove 58
around its inside diameter which allows it to be snapped to the
base member 32. Cover plate 56 has an circulate opening 60 therein,
as seen in FIG. 8, permitting the support leg 12 to pass
through.
Formed with base 32 is a funnel-shaped duct 62, as best seen in
FIG. 1, which connects through a series of radially extending ribs
64, as seen in FIGS. 1 and 4. Duct 62 is tapered outward at its
inlet end 66 to a diameter substantially increasing its cross
sectional area.
The outer cowling 68 is also formed with duct 62 and is connected
to duct 62 by a second series of ribs 70, as seen in FIGS. 1 and 4,
which have a similar lateral spacing, as previously-mentioned ribs
64. Base member 32, duct 62 and outer cowling 68 are all molded in
a single piece through joining ribs 64 and 70.
Removably positioned within outer cowling 68 is an inner cowling 72
which is also funnel-shaped from its larger intake end 74 to its
smaller discharge end 76. Most of the axial length of cowling 68 is
a constant diameter similar to discharge end 76.
Attached to the discharge end 76 is a circular grill 80. Inner
cowling 72 is held in place by a series of four tabs 78, as seen in
FIG. 7, which are positioned quadrantally around the periphery of
the intake end 74 of the cowling. Tabs 78 have hook-shaped ends
which, when fully inserted within the outer cowling 68, will engage
the edge of outlet cowling 68. These four tabs 78 can be deflected
inwardly individually by finger pressure, allowing the grill and
inner cowling to separate from the fan structure so as to provide
the necessary access to the interior of the fan. The remote
posititoning of the four tabs requires at least two separate hand
operations which is also a current safety requirement for fan
design.
Grill 80 includes a small center hub 82 and a series of
arcuate-shaped ribs 84 extending inwardly from the hub, curving to
the left, as seen in FIGS. 2 and 5, to the outer radius 86 of the
grill. The center of curvature point for each rib 84 lies on a
circle 88, as shown in FIG. 5, the radius of curvature of ribs 84
is approximately two-thirds the outer radius of the overall grill.
The circle 88 includes a locus of points for the center of
curvature of each rib 84 and has a radius approximately one-half
the outer radius 86 of the grill. The radius of hub 82 is
approximately one-fifth (1/5) the outer radius 86 of the grill. The
maximum lateral spacing between any pair of ribs 84 is inwardly
from the outer radius 86 of the grill at a point approximate
dimension X, as shown in FIG. 5. The impeller blade's point of
maximum power is located at approximately 0.6 times its radius.
This places the maximum power in a region of the grill wherein the
rib spacing is at its maximum. The longer length curved ribs 84, as
compared with a conventional straight rib, provides a less rigid
grill structure which can be desirable under certain circumstances
such as impact shocks.
In viewing FIG. 5, the fan blades not shown move in a clockwise
direction from left to right, while the grill ribs 84 curve to the
left from the center in the opposite direction which provides an
optimum flow of air at a standard power usage.
FIG. 6 shows a lateral cross section of a rib 84 with the upstream
edge 90 being curved with the remainder of the rib slightly tapered
in the overall shape of an airfoil.
Outer cowling 68 is convex in shape with a curve leading edge 92
which together with inner cowling 72 forms the cross sectional
shape of an airfoil which minimizes the amount of turbulence and
drag produced at the leading edge.
A conventional switch and rheostat for controlling the fan can be
located any place on wire 18 either remote of the support leg 12 or
preferably at the end 22.
Located between inner cowling 72 and outer cowling 68 is an annular
opening 94 which provides a handle for lifting the fan.
* * * * *