U.S. patent application number 11/520657 was filed with the patent office on 2008-03-20 for reversible fan blade for a ceiling-suspended fan.
Invention is credited to Karun Laisathit.
Application Number | 20080069698 11/520657 |
Document ID | / |
Family ID | 39188802 |
Filed Date | 2008-03-20 |
United States Patent
Application |
20080069698 |
Kind Code |
A1 |
Laisathit; Karun |
March 20, 2008 |
Reversible fan blade for a ceiling-suspended fan
Abstract
An improved ceiling fan blade for use on a ceiling fan having a
reversible motor and a plurality of said fan blades is provided in
which each ceiling fan blade is in the shape of a trapezoid and the
bottom part of the fan blade is wider than the tip of said fan
blade. Each of the fan blades has two side edges that are connected
to a central region of the fan blade, one of the side edges folds
upwardly from the central region and the other side edge folds
downwardly from the central region wherein each of the edges folds
in opposite directions from the central region.
Inventors: |
Laisathit; Karun; (Bangkruay
District, TH) |
Correspondence
Address: |
JAMES W. PRAVEL;PRAVEL INTELLECTUAL PROPERTY LAW, PC
1800 DIAGONAL ROAD, SUITE 600
ALEXANDRIA
VA
22314
US
|
Family ID: |
39188802 |
Appl. No.: |
11/520657 |
Filed: |
September 14, 2006 |
Current U.S.
Class: |
416/210R |
Current CPC
Class: |
F04D 29/34 20130101;
F04D 25/088 20130101; F04D 29/384 20130101 |
Class at
Publication: |
416/210.R |
International
Class: |
F04D 29/34 20060101
F04D029/34 |
Claims
1. A ceiling fan blade for use on a ceiling fan having a reversible
motor and a plurality of said fan blades wherein the improvement
comprises: a. Said fan blade is in the shape of a trapezoid and in
which the bottom part of said fan blade is wider than the tip of
said fan blade; b. Said fan blade has two side edges connected to a
central region of said fan blade, one of said side edges folds
upwardly from the central region and the other side edge folds
downwardly from the central region wherein each of said edges folds
in opposite directions from the central region.
2. The ceiling fan blade claimed in claim 1 wherein the plurality
of said blades are mounted on a base connected to a shaft that is
connected to the reversible motor of the ceiling fan.
3. The ceiling fan blade according to claim 1 wherein the angle
between each of said edges and the central region is in the range
of approximately 1 to 30 degrees.
4. The ceiling fan blade claimed in claim 1 wherein said blade
includes a bracket mounted on said bottom part and said bracket is
mounted on a base connected to a shaft that is connected to the
reversible motor of the ceiling fan.
5. The ceiling fan blade according to claim 1 wherein the fan blade
is constructed from materials selected from the group consisting of
polymer and wood.
6. The ceiling fan blade according to claim 1 wherein said fan
blade is constructed of metal.
7. The ceiling fan blade according to claim 5 wherein said blades
are at least 3/16 inches in thickness.
Description
FIELD OF THE INVENTION
[0001] This invention relates to the field of ceiling fan
blades.
BACKGROUND OF THE INVENTION
[0002] Ceiling-suspended fans can be generally separated into 2
categories based on the types of blade rotation. [0003] (1) One-way
rotation ceiling fan. The blade is rotated only in one direction.
The airflow is diverted downwardly. [0004] (2) Reversible ceiling
fan. The blade is able to rotate in two directions. The airflow can
either be diverted downwardly or upwardly.
[0005] The ceiling fan in category (1) is for general usage. The
objective is to create ventilating airflow one-way downwardly. The
ceiling fan in category (2) is not only able to serve the
objectives achieved by the former, but is also able to ventilate
designated areas in order to help conserve thermal energy during
hot or cold weather. The ceiling fan in category (2) comprises two
components; a reversible electric motor and a fan blade that can
create air flow in both direction of rotation.
[0006] Prior art patents exist for fan blades. For example, U.S.
Pat. No. 5,575,624 shows a conventional "S" shaped fan blade for a
reversible ceiling fan. The conventional "S" shaped fan blade shown
in U.S. Pat. No. 5,575,624 does not provide the desirable high
airflow volume that the shape of the present inventive fan blade
provides. Empirical test results prove that the shape of the folded
edges of the blades of the instant invention significantly
outperforms the "S" shape of prior art fan blades.
[0007] The inventive fan blade may be made from wood, plastic,
metal or other materials. The design is unique but normal fan
capabilities still remain. In addition, the fan blade is able to
rotate in the opposite direction to create airflow. The amount of
airflow generated by the fan blade is almost equal in both
directions. This particular fan blade is compatible with both types
of ceiling fan, whether or not it has a blade bracket. The design
can also be used with any ceiling fan that includes multiple
blades.
SUMMARY OF THE INVENTION
[0008] What is needed is a novel and non-obvious fan blade
configuration that will improve the efficiency and airflow of a
reversible ceiling fan.
[0009] An improved ceiling fan blade for use on a ceiling fan
having a reversible motor and a plurality of said fan blades is
provided in which each ceiling fan blade is in the shape of a
trapezoid and the bottom part of the fan blade is wider than the
tip of said fan blade. Each of the fan blades has two side edges
that are connected to a central region of the fan blade, one of the
side edges folds upwardly from the central region and the other
side edge folds downwardly from the central region wherein each of
the edges folds in opposite directions from the central region.
[0010] The trapezoidal shape allows the blade to move as much air
toward the tip of the blade as toward the bottom part of the blade
but reduces the amount of energy required to move the blade by the
ceiling fan motor.
[0011] The angle between the folded edges of the fan blade and the
central region is in the range of approximately 1 to 30
degrees.
[0012] Each fan blade can be connected directly to a base on shaft
that is connected to the reversible motor or can be connected to an
intermediate bracket that is connected to the base on the shaft
that is connected to the reversible motor of the ceiling fan.
[0013] The fan blades can be constructed of metal, polymer or wood.
If constructed of polymer or wood, and positioned seven feet or
higher above the ground, the blades are generally at least 3/16''
in thickness for safety purposes and to satisfy the requirements of
the Underwriters Laboratory UL 507.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 is an isometric view of the three of the inventive
fan blades mounted on a reversible ceiling fan.
[0015] FIG. 2a shows a top view of a fan blade of the invention
including a bracket to mount to the motor of a reversible ceiling
fan.
[0016] FIG. 2b shows an end view of the fan blade shown in FIG.
2a.
[0017] FIG. 3a shows a top view of a fan blade of the invention
that mounts directly to the motor of a reversible ceiling fan.
[0018] FIG. 3b shows an end view of the fan blade shown in FIG.
3a.
[0019] FIG. 4 shows an isometric view of an inventive fan
blade.
[0020] FIG. 5 shows of an end view of the fan blade of FIG. 4.
DETAILED DESCRIPTION OF THE INVENTION
[0021] The fan blade A of the invention is generally trapezoidal in
shape. The blade A is typically wider at the bottom part of the
blade 26 on the end closest to the fan and narrows toward the tip
of the blade 27. The side edges 2,3 of the blade A are folded from
a central region 7, one edge 2 folded upwardly and the other edge 3
folded downwardly. The preferred angle .theta. between the folded
edges and the central region is between approximately 1 to 30
degrees (See FIG. 5).
[0022] Blade brackets 6 can be attached to the bottom part of the
blade A (FIG. 2a) or tabs 12 of the blade A can be directly mounted
to the base 24 of the shaft 22 without brackets, as shown in FIG.
3a.
[0023] The directions of airflow are illustrated in FIG. 5. When
the blade A is rotated to direction 16a, the airflow is diverted
upward 16b. When the blade A is rotated to direction 18a, the
airflow is diverted downward 18b.
[0024] There are many advantages of the inventive blade design. One
advantage is the reversible feature, which creates almost the same
amount of airflow in both directions 16b, 18b. The tip 27 of the
inventive blade A is narrower than the bottom 26, therefore less
material is utilized but the amount of airflow remains the same.
This reduction in blade size helps to make the blade A lighter in
weight. The reduction in the weight of the blade A reduces the
workload and the energy used from the fan motor 25a. The amount of
airflow can be altered by adjusting the angle of the side edges 2,3
of the blade A relative to the central region. This feature of the
blade design gives more blade efficiency than any other types of
fan blades currently used on ceiling fans. The preferred angle
between the side edges and the central region is approximately 1 to
30 degrees. It is contemplated that the angle between the side
edges and the central region be made adjustable and/or variable to
fine-tune the amount of airflow produced by the inventive fan blade
A. For example, the angle .theta. between one edge 2 and the
central region 7 could be different from the angle .theta. between
the other edge 3 and the central region 7.
[0025] Tests were conducted to compare the airflow produced by a
set of the inventive fan blades with the airflow produced by a set
of conventional "S" shaped fan blades. The testing was conducted on
Jul. 12-13, 2006 by the Physical Testing Laboratory of the Thailand
Institute of Scientific and Technological Research (TSIR)
Industrial Metrology and Testing Service Centre, an independent
testing laboratory. Three of each type of fan blade was tested
under similar conditions on the same fan motor to obtain a valid
experimental comparison of airflow performance. The dimension of
the testing room was 3.8 meters wide, 10 meters long and 2.6 meters
high. The distance of the ceiling fan from the ceiling was 32
centimeters. The distance of the anemometer from the fan was 150
centimeters. A Model CF-56-MI fan motor used for the testing each
set of fan blades. The supply voltage to the fan motor was 120V at
60 Hz. A Davis Instrument Mfg. Co. anemometer was used to measure
the airflow rate from each set of fan blades. The set of inventive
fan blades showed significantly improved airflow in comparison with
the set of convention "S" shaped fan blades. Specifically, when a
fan blade constructed with folded edges according to the instant
invention was tested against conventional "S" shaped fan blades,
each having the same surface area, the test results were as
follows:
TABLE-US-00001 Cubic Feet of Airflow Blade Tested per Minute
Conventional "S" Shaped Blade 7213.48 Reversible Inventive Folded
Edge Blade 8926.91
[0026] According to the independent test results, the set of
inventive blades produced a surprising and unexpected resulting
gain of over 23% in airflow over the set of conventional "S" shaped
fan blades.
[0027] In order to comply with the ceiling fan installation
regulation for fan blade suspended seven feet or more above the
ground, the inventive blades that are constructed of polymer or
wood, are 3/16 inches or more in thickness. This reversible blade
design is able to meet this Underwriters Laboratory Section 507
requirement by using material like wood or plastic in which its
thickness is not less than 3/16 inches thick and the ceiling fan
motor still operates normally.
[0028] The foregoing disclosure and description of the invention
are illustrative and explanatory thereof, and various changes to
the angular configuration described or other changes in shape,
materials or other details provided will not depart from the spirit
and scope of the invention as claimed.
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