U.S. patent application number 15/489562 was filed with the patent office on 2017-08-03 for propeller.
This patent application is currently assigned to Sharrow Engineering, LLC. The applicant listed for this patent is Sharrow Engineering, LLC. Invention is credited to Gregory Charles Sharrow.
Application Number | 20170218772 15/489562 |
Document ID | / |
Family ID | 50881135 |
Filed Date | 2017-08-03 |
United States Patent
Application |
20170218772 |
Kind Code |
A1 |
Sharrow; Gregory Charles |
August 3, 2017 |
Propeller
Abstract
A propeller having a central post to which one or more blades
are connected. The blades are disposed and configured to pull air
in from the propeller's sides toward the propeller's axis of
rotation to create pressure in an area in the vicinity of the
center of the propeller's rotating axis for generating thrust.
Inventors: |
Sharrow; Gregory Charles;
(Cherry Hill, NJ) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Sharrow Engineering, LLC |
Philadelphia |
PA |
US |
|
|
Assignee: |
Sharrow Engineering, LLC
Philadelphia
PA
|
Family ID: |
50881135 |
Appl. No.: |
15/489562 |
Filed: |
April 17, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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13843344 |
Mar 15, 2013 |
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15489562 |
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61735140 |
Dec 10, 2012 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F01D 5/14 20130101; Y10T
29/49332 20150115; Y02E 10/72 20130101; F01D 5/141 20130101; B64C
11/00 20130101; B64C 11/16 20130101; Y02E 10/721 20130101; B63H
1/265 20130101 |
International
Class: |
F01D 5/14 20060101
F01D005/14; B64C 11/16 20060101 B64C011/16; B63H 1/26 20060101
B63H001/26 |
Claims
1. A propeller comprising: a central post coincident with a
rotational axis; one or more blades each having a distal end and a
proximate end; each of the one or more blades comprising a top
section, a bottom section, and a side section, the side section
disposed at or toward the distal end; the side section having a
non-zero blade angle that causes fluid to be pulled inward from the
side section toward the propeller axis of rotation; the length from
the central post to the distal end of the blade's leading edge is
greater than the length from the central post to the distal end of
the blade's trailing edge; the bottom section having a coarser
blade angle than the top section; the top section and bottom
section of each of the one or more blades connected at the
proximate end to and extending radially outward from the central
post; a gap between the central post connections of the top section
and bottom section of at least one of the one or more blades; the
blades further configured to pull fluid from the propeller's front
to its back; and wherein in the top section extends from the
central post outward to the side section at the top section distal
end and the side section folds back toward the central post to the
bottom section distal end so a top surface of the top section
become a bottom surface of the bottom section.
2. The propeller of claim 1 wherein the blades are in loop form,
wherein each of the blades in loop form spins in the same plane of
rotation.
3. The propeller of claim 1 wherein the cross-section of at least
one of the top section or bottom section of the one or more blades
is shaped substantially like an airfoil.
4. The propeller of claim 1 comprising at least one pair of blades
opposing one another about the rotational axis.
5. The propeller of claim 4 wherein the pair of opposing blades
form a single, contiguous loop.
6. The propeller of claim 4 wherein the pair of blades has a first
blade intersecting the central post at a first blade intersection
and a second opposing blade intersecting the central post at a
second blade intersection, wherein the angle of the first blade
intersection with respect to the rotational axis is different from
the angle of the second blade intersection with respect to the
rotational axis.
7. The propeller of claim 6 wherein the range of difference between
the angle of the first blade intersection with respect to the
rotational axis and the angle of the second blade intersection with
respect to the rotational axis is in the range of about 40.degree.
to about 60.degree..
8. The propeller of claim 1 wherein at least one of the one or more
blades is wider at its distal end as compared to its proximate
end.
9. The propeller of claim 1 wherein at least one of the blade top
section, bottom section or side section of at least one of the one
or more blades has a median line that is curved.
10. The propeller of claim 9 wherein each of the top section,
bottom section and side section of at least one of the one or more
blades is curved.
11. The propeller of claim 9 wherein a twist forming the curvature
of the blades is in the range of about 30 degrees to about 40
degrees.
12. The propeller of claim 11 wherein the twist forming the
curvature of the blades is approximately 35 degrees.
13. The propeller of claim 1 further comprising one or more
additional blades disposed in stacked formation with respect to the
propeller.
14. The propeller of claim 9 wherein the blades are graduated in
thickness laterally across the blade.
15. The propeller of claim 13 wherein the blades are graduated in
width from a smaller width at the proximate end to a larger width
at the distal end.
16. The propeller of claim 1 wherein at least the top and bottom
blade sections exhibit a coarse pitch in the vicinity of the axis
of rotation and decreasing pitch extending radially outward from
the axis of rotation.
17. The propeller of claim 1 wherein at least the top and bottom
sections of at least one of the blades have substantially linear
median lines.
18. The propeller of claim 1 comprising wing segments connecting
the top and bottom portions of each blade, wherein the wing
segments are shaped and disposed at intervals radiating from the
central post for pulling air inward to the center of the axis of
rotation.
19. The propeller of claim 1 wherein the top blade portion is not
symmetrical with the bottom blade portion.
20. The propeller of claim 1 wherein the blade top portion
intersects the central post at a blade top portion angle of
intersection and the blade bottom portion intersects the central
post at a blade bottom portion angle of intersection and wherein,
as measured from a line perpendicular to the longitudinal axis of
the propeller, the blade bottom portion angle of intersection is
greater than the blade top portion angle of intersection.
21. The propeller of claim 20 wherein the difference of angle of
intersection between the top blade portion and the bottom blade
portion is in the range of 5.degree. to about 20.degree..
22. The propeller of claim 21 wherein the blade top portion angle
of intersection is about 25.degree. and the blade bottom portion
angle of intersection 15.degree.
23. A device selected from the group consisting of an aircraft,
watercraft, wind turbines, cooling devices, heating devices,
automobile engines, and air circulation devices, wherein the device
has at least one propeller according to claim 1.
24. A method of manufacturing a propeller comprising: selecting a
desired direction of airflow; selecting a desired quantity of
thrust; selecting a blade curvature, combination of blades and
blade intersection angles to create the selected airflow and
thrust; and creating a propeller according to claim 1 with the
selected blade curvature and blade intersecting angles.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 13/843,344, filed Mar. 15, 2013, which is a
non-provisional patent application of U.S. provisional application
61/735,140, filed Dec. 10, 2012. The aforementioned applications
are incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] This invention relates to blade apparatuses such as
propellers.
[0003] Typically, propellers have been used in devices such as
aircraft, watercraft, turbines, and other like apparatuses in a
wide variety of configurations for transmitting power by converting
rotational motion into thrust or fluid flow.
[0004] A propeller generally consists of two or more blades
attached to a central post or hub with the blades curved, twisted,
or otherwise shaped to generate a pressure difference between the
forward and rear surfaces of a blade to propel a fluid, such as
water or air, past the blades. The shape, the pitch, and the twist
of the blade all factor in the working efficiency of the
propeller.
[0005] There have been numerous attempts at increasing propeller
performance by altering blade designs. Such approaches have been
successful to a degree but often result in propellers with limiting
properties such as limited achievable rake and pitch. There is a
need to provide a propeller that exhibits improved properties
compared to conventional propellers.
SUMMARY
[0006] Embodiments of the invention provide a propeller that pulls
air inward from the blade's side sections toward the propeller's
axis of rotation and from the propeller's front to its back. The
propeller has a central post coincident with a rotational axis and
one or more blades disposed around the central axis. Each blade has
a distal end and a proximate end. The blades include a top section,
a bottom section, and a side section, with the side section
disposed at or toward the distal end. The top section and bottom
section of the one or more blades are connected at their proximate
ends to, and extend radially outward from, the central post. There
is a gap between the central post connections of the top section
and bottom section of blades wherein air is compressed upon
rotation of the propeller. The blade top portion intersects the
central post at a blade top portion angle of intersection and the
blade bottom portion intersects the central post at a blade bottom
portion angle of intersection. As measured from a line
perpendicular to the longitudinal axis of the propeller, the blade
bottom portion angle of intersection is greater than the blade top
portion angle of intersection. The top blade portion can be
non-symmetrical with the bottom blade portion.
[0007] The propeller blades can be in loop form, wherein each of
the blades in loop form spins in the same plane of rotation. At
least one of the blade sections can exhibit a non-zero blade angle.
The cross section of the blades can have an airfoil shape. Blades
can be wider at their distal end as compared to their proximate
end. Blades have a median line that can be straight or curved,
independent of twists in the blade.
[0008] The propeller can have one or more pairs of blades opposing
one another about the rotational axis. The pair of opposing blades
can form a single, contiguous loop. The angles of intersection with
respect to the rotational axis can be different between the
opposing blades.
[0009] Propellers can be stacked on top of one another with or
without spaces therebetween. Further, propellers can be comprised
of a plurality of blades disposed in a helix about the central
post.
[0010] The propeller blades can have a coarse pitch in the vicinity
of the axis of rotation and decreasing pitch extending radially
outward from the axis of rotation. Side sections of the blades
exhibit a non-zero pitch.
[0011] The invention also includes devices having any of the
disclosed propellers.
[0012] The invention further comprises a method of manufacturing a
propeller comprising: selecting a desired direction of airflow,
selecting a desired quantity of thrust, and selecting a blade
curvature, combination of blades and blade intersection angles to
create the selected airflow and thrust.
DESCRIPTION OF THE DRAWINGS
[0013] For further detail regarding illustrative embodiments of the
invention, reference is made to the detailed description provided
below, in conjunction with the following illustrations:
[0014] FIG. 1 is a side view of a schematic representative of a
propeller according to an illustrative embodiment of the
invention.
[0015] FIG. 2 is depicts a propeller with two opposing blades
according to an illustrative embodiment of the invention.
[0016] FIG. 3A is a side view of a blade in loop form according to
an illustrative embodiment of the invention.
[0017] FIGS. 3B and 3C are alternative cross-sectional views of the
blade shown in FIG. 3A according to illustrative embodiments of the
invention.
[0018] FIGS. 3D and 3E are alternative views of the blade shown in
FIG. 3 according to an illustrative embodiment of the
invention.
[0019] FIG. 4 is a cross-sectional view of a propeller with two
opposing blades according to an illustrative embodiment of the
invention.
[0020] FIG. 5 depicts a propeller with uprights attaching the upper
and lower blade portions according to an illustrative embodiment of
the invention.
[0021] FIG. 6A shows a three-loop propeller according to an
illustrative embodiment of the invention.
[0022] FIG. 6B depicts a side view of a three-loop propeller
according to an illustrative embodiment of the invention.
[0023] FIG. 7A depicts a four-loop propeller according to an
illustrative embodiment of the invention.
[0024] FIG. 7B is a side view of a four-loop propeller according to
an illustrative embodiment of the invention.
[0025] FIG. 8 shows a multiple-loop propeller according to an
illustrative embodiment of the invention.
[0026] FIG. 9 is an isometric view of a two-loop propeller with
unattached bottom blade sections.
[0027] FIG. 10 is an isometric view of a stacked propeller
according to an illustrative embodiment of the invention.
[0028] FIG. 11 depicts a propeller according to an illustrative
embodiment of the invention.
[0029] FIG. 12 depicts a stacked propeller according to an
illustrative embodiment of the invention.
[0030] FIGS. 13A-B depict a top view and side view, respectively of
a propeller with open-loop blades according to n illustrative
embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0031] Generally, the invention comprises a propeller having one or
more "blades" wherein the blades are shaped to create an air flow
inward from the propeller sides toward the axis of rotation, for
example in a plane perpendicular to the axis of rotation, and also
to create airflow in the longitudinal direction of the rotational
axis, such as from "front" to "back" of the propeller. The blades
are shaped so that air is pulled inward by the blades' outer
portions, or "supports", and compressed in the vicinity of the
propeller's center. Consequently, as the propeller spins, the
blades create pressure in the central area, which, in turn, results
in greater thrust. Conversely, when spinning in the opposite
direction of rotation, the propeller will create reverse thrust. In
illustrative embodiments of the invention, the amount of reverse
thrust may not equal the amount of thrust generated.
[0032] The term "blade" is used herein merely to designate a
component that rotates about an axis to generate a desired airflow,
and is not intended to denote a specific shape, such as flat.
[0033] In illustrative embodiments of the invention, the blade
includes three sections: top, bottom, and side. As a propeller can
be disposed at various angles, an example of the use of the terms
is shown in FIG. 1, and it is noted that, for example, if a
propeller 102 is rotating in a vertical plane "top" and "bottom"
may not correlate with the traditional meaning of those terms.
Propeller 102 has two blades 104, 106. Blade 106 has a top section
108, a bottom section 110 opposing top section 108, and a side
section 112. Side section 112 is at a distal end of top section 108
and connects top section 108 with bottom section 110. In this
particular embodiment, side section 112 is a general area of the
blade between the top section and the bottom section. In other
embodiments, a blade's side section can be a discrete portion of
the blade such as the side section 516 in FIG. 5.
[0034] The term "blade angle", measured in degrees, when used
herein is defined as the angle between a lateral cross section of a
blade and the plane of rotation. The term "pitch" is used herein
interchangeably with "blade angle." Embodiments of the invention
provide blades having at least one section exhibiting a non-zero
blade angle.
[0035] The term "front" when used with respect to a propeller
designates the side/face of the propeller, which when viewed will
show counter clockwise motion of the propeller. The propeller
"back" will be the opposing side. As the propeller spins, the
direction of airflow will preferably be from front to back.
[0036] In illustrative embodiments of the invention, the length 114
from the central post to the distal end of the blade's leading edge
is greater than the length 116 from the central post to the distal
end of the blade's trailing edge. This decrease in blade length
from the length at the blade's leading distal edge to the length at
the blade's trailing distal edge can result in greater compression
of air and greater thrust as compared to a comparable propeller
design without this feature.
[0037] FIG. 2 is a front view of a propeller according to an
illustrative embodiment of the invention. This embodiment comprises
two blades in loop form 202, 204, opposing one another. As used
herein a "loop" defines a blade with a continuous curved surface.
The propeller includes a central post 206 to which the blades are
connected. The central post is coincident with the propeller's axis
of rotation. It is noted that the term "post", as used herein, does
not indicate a particular shape or configuration, but merely
indicates a component to which blades are attached or by which they
are secured to one another. In this illustrative embodiment,
proximal portion 210 of each loop has a width that is less than the
width of distal portions 212. An illustrative example of the ratio
of widths is approximately 2:1. As drawn, the propeller spins
counterclockwise as shown by the curved arrows. This creates an air
flow toward the propeller center from all sides as shown for
example by the triple arrows on the right and left sides of the
diagram. Air also would flow into the page (front to back) for the
configuration shown as the propeller spins counterclockwise.
[0038] By providing curved blades, various examples of which are
shown in the figures, air flow is more directed as compared to
flatter blades. Although the drawings show blades generally in the
form of full loops, the blades may be curved to a lesser extent so
that a closed loop is not formed, provided that the desired airflow
is created.
[0039] FIG. 3A depicts a looped blade according to an illustrative
embodiment of the invention. FIG. 3A depicts blade 302 attached to
a central post 306 of a propeller according to an illustrative
embodiment of the invention. The axis of rotation of blade 302 is
coincident with the longitudinal axis of central post 306 in this
embodiment. Blade 302 has a top section 308 and a bottom section
310. The median line of blade 302 is defined as the locus of points
midway between the blade's leading edge 312 and its trailing edge
314 as shown by the broken line 316 running from the proximal end
318 to the distal end 320 of blade 302. For some blade
configurations, the median line will not be continuous from top
section through side section to bottom section. The median line of
blade 302 is curved providing a curved appearance to the blade
sections. In other embodiments, blade sections may be cambered or
otherwise curved, angular or flat, or a combination thereof. For
example, FIG. 5, further discussed below, depicts an embodiment
wherein blade sections have substantially linear, and possibly
non-continuous median lines.
[0040] Air is compressed in the vicinity of central post 306 as the
propeller spins. As seen in FIGS. 3A-3B, a gap 342 between bottom
portion 310 and top portion 308 of blade 302 allows a larger volume
of air to be compressed than if a gap did not exist. Air is caught
on the inside surface of blade 302, thus pulling in air and
creating the air flow from the sides as described above, while the
outside surface of blade 302 functions to push the air toward the
back of the propeller.
[0041] FIGS. 3B and 3C depict cross sections of blade 302 taken
along lines B-B and C-C of FIG. 3A, respectively. Cross-section B-B
shows an airfoil shape comparable to a cross section of an airplane
wing. As shown in FIG. 3C, surface 332 of blade 302 is curved,
while the opposing surface 330 is substantially flat. The cross
section of blade 302 is tapered laterally so that at a first area
334 it is thinner than at a second, opposing area 336, also
comparable to an airplane wing. Other blade configurations are
within the scope of the invention and will depend in part on the
desired load on the propeller.
[0042] Referring to FIG. 3B, blade 302 intersects central post 306
at a first blade intersection 338 and a second blade intersection
340. In this illustrative embodiment of the invention, first and
second blade intersections 338, 340 intersect central post 306,
which can be at about the same angle 0 as measured counterclockwise
from a line perpendicular to the longitudinal axis of central post
306, wherein the designated reference line appears as a
"horizontal" line in FIG. 3B. An illustrative angle of intersection
is about 25.degree., with an illustrative range being about
10.degree. to about 35.degree.. A further illustrative range of
angles of intersection is about 15.degree. to about 25.degree..
[0043] In exemplary embodiments of the invention the intersection
angle of the bottom portion of the blade with the central post is
more extreme than the angle of intersection of the top portion of
the blade with the central post. Generally, angles of intersection
can be in the range of about 1.degree. to about 89.degree.. By
"extreme" it is meant more toward the vertical. An illustrative
difference between the angle of intersection of the top portion of
the blade as compared to the angle of intersection of the bottom
portion of the blade is about 10.degree.. An illustrative range is
about 5.degree. to about 20.degree. and a further illustrative
range is about 7.degree. to about 15.degree.. In a particular
embodiment of the invention the angle of intersection of the top
portion of the blade is about 30.degree. and the angle of
intersection of the bottom portion of the blade is about
40.degree.. In a further embodiment of the invention, the angle of
intersection of the top portion of the blade is about 75.degree.
and the angle of intersection of the bottom portion of the blade is
about 85.degree..
[0044] Blade 302 as shown in FIGS. 3A-C exhibits a coarse blade
angle, or pitch, near the axis of rotation with the pitch
decreasing radially outward from the axis of rotation. Despite this
downward gradient, the outermost point of the blade will still
exhibit non-zero pitch. In an alternative embodiment of the
invention, the blade may have a more course blade angle at the
farthest point from the axis of rotation.
[0045] FIGS. 3D and 3E depict blade 302 as viewed so central post
306 is perpendicular to the page. In FIG. 3D blade 302 would be
rotating clockwise and has a leading edge 346 and a trailing edge
344. In FIG. 3E, blade 302 would be rotating counterclockwise.
[0046] In embodiments wherein two blades oppose one another, such
as blades 202 and 204 in FIG. 2, the pitches of opposing blade
intersections on either side of the axis of rotation differ from
each other. So for example, in FIG. 4 you have a first blade 402
having a first blade intersection 404 at angle .theta..sub.A and a
second blade intersection 406 at an angle .theta..sub.B, and an
opposing blade 410 would have a first blade intersection angle and
a second blade intersection angle of .theta..sub.A.+-.x and
.theta..sub.B.+-.x, respectively. So in other words, the pitch of
opposing blade intersections differs. An illustrative difference in
pitch between opposing blade intersections is about 50.degree.,
wherein for example one blade intersection has a 25.degree. pitch
and the opposing blade has an intersection with a negative
25.degree. pitch. Differences can be equally or unequally
distributed. A general range of differences between the pitch of
opposing blades is about 40.degree. to about 60.degree.. The pitch
of opposing blade intersections need not be equal from the plane of
rotation as in the preceding example.
[0047] FIG. 5 depicts an illustrative embodiment that includes two
blades 502, 504 with substantially non-curved median lines. Median
line 506 of top blade section 508 and median line 510 of bottom
blade section 512 of blade 502 are substantially linear and may or
may not be parallel. Blade 504 also has a substantially linear
median line. One or more substantially vertical wing segments 514,
516 connect top blade section 508 and bottom blade section 510 at
intervals radiating from a central post 518 up to but not
necessarily including the distal end 520 of blade 502. Blade 504
may have similar or the same vertical segments. Although, the
blades are flattened to an extent and would not necessarily be
considered a "loop" with a continuous surface, the desired airflow
may nonetheless be created with the addition of the wing segments,
514, 516, or both. As the propeller spins, wing segments 514, 516
pull air in from the sides toward central post 518, thus creating
the desired airflow.
[0048] In a further embodiment of the invention, such as shown in
FIG. 11, top blade section 1102 and bottom blade section 1104 are
not symmetrical. This can be accomplished, for example, by bottom
section 1104 being longer than the top section 1102, with a side
section 1106 angled toward the front of the propeller to connect to
the shorter top section 1102. This can facilitate the airflow being
pulled in from the side section to propel the blade forward. In
general, a more extreme angle between the side section and the top
section of the blade will result in more thrust and a higher
forward rake for the top section of the blade.
[0049] FIGS. 6A and 6B show a propeller with three loop-shaped
blades 602, 604, 606, according to an illustrative embodiment of
the invention. FIG. 6A is a view of the propeller rotating so that
counterclockwise rotation would cause airflow into the page, and
FIG. 6B is a side view of the propeller. Blades 602, 604, 606
radiate from central post 608. Blades 602, 604, 606 are generally
coplanar. Any number of loops can be combined to obtain the desired
air flow. See for example FIGS. 7A, 7B with four blades and FIG. 8
with eight blades.
[0050] Propellers can be "stacked" so they rotate in different
planes. By "stacked" it is not meant that they necessarily abut one
another. The stacked propellers can have gaps between them. They
can be of uniform size or graduated from smaller to larger in a
direction perpendicular to the plane of rotation from back to
front, or larger to smaller in that direction. For example, FIG. 10
shows an eight-loop propeller 1002 having a first plane of rotation
stacked onto another eight-loop propeller 1004 having a second
plane of rotation. The blades of propeller 1002 are attached to
central post 1006, and the blades of propeller 1004 are attached to
central post 1008. Although FIG. 10 illustrates two discrete
central posts 1006 and 1008, propellers may also be stacked on a
single central post.
[0051] FIG. 12 depicts a further embodiment of a stacked propeller.
Blades are disposed about a central post in a helix fashion.
[0052] FIGS. 7A and 7B depict a propeller having four blades 702,
704, 706, 708, according to an illustrative embodiment of the
invention. Blades 702, 704, 706, 708 radiate from a central post
710 wherein of blades 702, 704, 706, 708 would generally spin in
the same plane as the others. As can be seen in FIG.7B, in this
illustrative embodiment, there is a "gap" 712 between the
attachment locations of a top portion of each blade and a bottom
portion of each blade along central post 710, with which the axis
of rotation is coincident. The term "gap" is used herein to
describe the space around the axis of rotation between the center
of the blade intersections with a central post created when a
blade's top and bottom portion are attached at different
longitudinal locations along a central post or axis of rotation.
FIGS. 3A-B depicts the location of the gap as shown by line 342. In
certain embodiments of the invention, the blade bottom portion may
not be attached to the central post, such as shown in FIGS. 9 and
13A-B, in which case the gap is the distance between the center of
the top blade portion intersection with the central post and the
center of where the bottom blade portion would intersect the
central post if it was extended to reach it.
[0053] As the propeller spins, air is pulled towards and compressed
in the vicinity of gap 712. Propellers can be designed with various
gap sizes. An illustrative gap size range is approximately about 2%
to 55% of the length of a propeller's. Another illustrative gap
size range is about 20% of a propeller's blade length to about 35%
of a propeller's blade. A third illustrative gap size range is
about 30% of a propeller's blade length to about 55% of a
propeller's blade length. Generally as the gap increases a larger
volume of air can be compressed, thus increasing a propeller's
thrust capability.
[0054] Whether or not blades have curved or straight median lines,
they may be twisted, such as about the median line for example. A
twist can be seen for example in FIG. 5. Both top portion 508 and
bottom portion 512 of blade 502 have an apparent twist. Curved
blades can also be additionally twisted, such as can been seen in
FIGS. 7A-B, or as would result from a difference in blade
intersection angles .theta. as shown in FIG. 4. In an illustrative
embodiment of the invention, the propeller has a twist forming the
curvature of the blades or relative curvature of opposing blades
that is approximately 35 degrees. An illustrative range of twist is
in the range of about 30 degrees to about 40 degrees. Other degrees
of twisting are within the scope of the invention and can create
various degrees and directions of airflow.
[0055] FIG. 8 depicts an illustrative embodiment of the invention
with eight "blades" 802, 804, 806, 808, 810, 812, 814, 816 made of
four circles that are all slightly angled but have no half
turn.
[0056] In an exemplary embodiment of the invention, at least the
front edges of the loops are thin to cut through the air, but other
edge shapes may be beneficial to achieve a desired air flow
pattern. In general, the specific shape, quantity and arrangement
of the loops can be chosen to create a desired air flow
pattern.
[0057] FIG. 9 depicts a propeller having blades 902, 904 in loop
form opposing one another wherein the bottom blade sections 906,
908 of blades 902, 904 are not attached to central post 910.
Instead, "brace" 912 flexibly couples bottom blade section bottom
906 to top blade section 914. Similarly, brace 916 flexibly couples
bottom blade section 908 to top blade section 918. A "brace" as
used herein is a blade component used to flexibly couple disparate
blade sections. A brace can be made of steel, aluminum, composite
materials such as carbon and fiber glass, or any other suitable
blade material. Braces 912, 916 are angled with respect to the
plane of rotation to pull air in toward the axis of rotation as the
propeller rotates, thus creating drag. A brace may be angled in the
same way as a blade's side section to achieve the desired air flow.
Further, the thickness, length, width, and other such
characteristics of a brace are designed to achieve desired
operation of a particular blade application, such as by way of an
example, flight. Blades 902, 904 are disposed with respect to
central post 910 in this manner to provide the flexibility of
adjusting their pitches. By way of illustration but not limitation,
when used as a propeller in an aircraft, the braces allow for the
blades 902, 904 to be manipulated to change pitch during activities
such as take-off, flight, or landing. The propeller can include an
adjustment mechanism to allow selectable variations in the gap
formed between top blade sections 914, 918 and bottom blade
sections 906, 908, respectively.
[0058] FIGS. 13A-B depict a top view and side view, respectively of
a further embodiment of a propeller with open-loop blades according
to an illustrative embodiment of the invention. This version does
not include the braces as provided in FIG. 9.
[0059] The invention includes various devices having various
embodiments of the disclosed propeller employed therein. For
example, the invention includes the following illustrative devices:
aircraft, watercraft, wind turbines, cooling devices, heating
devices, automobile engines, and air circulation devices. The
invention also includes a method of manufacturing a propeller
according to any of the embodiments described, pictured or claimed
herein; a method of manufacturing a device comprising any of the
aforementioned propellers; a method of manufacturing a product
wherein the method includes installing a device containing any of
the aforementioned propellers.
[0060] Various embodiments of the invention have been described,
each having a different combination of elements. The invention is
not limited to the specific embodiments disclosed, and may include
different combinations of the elements disclosed or omission of
some elements and the equivalents of such structures.
[0061] While the invention has been described by illustrative
embodiments, additional advantages and modifications will occur to
those skilled in the art. Therefore, the invention in its broader
aspects is not limited to specific details shown and described
herein. Modifications, for example, the number of blades and
curvature of the blades, may be made without departing from the
spirit and scope of the invention. Accordingly, it is intended that
the invention not be limited to the specific illustrative
embodiments, but be interpreted within the full scope of the
appended claims and their equivalents.
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