THIN AIRFOIL CEILING FAN BLADE
A fan blade comprising a root end, a blade region, and a transition region. Wherein each of the root end and blade region comprise a unique profile, and wherein the transition region comprises a profile which transitions the root end profile to the blade region profile. The root end profile comprises a substantially convex top surface, a substantially concave domed sector, and reliefs to allow for the root end to be coupled with a similarly shaped fan hub extrusion. The blade region profile comprises a substantially convex top surface and bottom surface which terminate at a leading edge and trailing edge. The blade region slopes upward along a length of the blade region and terminates at a curved tip.
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This application claims priority to U.S. Provisional Patent Application Ser. No. 61/588,932, filed Jan. 20, 2012, entitled “Thin Airfoil Ceiling Fan Blade,” the disclosure of which is incorporated by reference herein.
BACKGROUNDA variety of fan systems have been made and used over the years in a variety of contexts. For instance, various ceiling fans are disclosed in U.S. Pat. No. 7,284,960, entitled “Fan Blades,” issued Oct. 23, 2007; U.S. Pat. No. 6,244,821, entitled “Low Speed Cooling Fan,” issued Jun. 12, 2001; U.S. Pat. No. 6,939,108, entitled “Cooling Fan with Reinforced Blade,” issued Sep. 6, 2005; and U.S. Pat. No. D607,988, entitled “Ceiling Fan,” issued Jan. 12, 2010. The disclosures of each of those U.S. patents are incorporated by reference herein. Additional exemplary fans are disclosed in U.S. Pat. No. 8,079,823, entitled “Fan Blades,” issued Dec. 20, 2011; U.S. Pat. Pub. No. 2009/0208333, entitled “Ceiling Fan System with Brushless Motor,” published Aug. 20, 2009; and U.S. Pat. Pub. No. 2010/0278637, entitled “Ceiling Fan with Variable Blade Pitch and Variable Speed Control,” published Nov. 4, 2010, the disclosures of which are also incorporated by reference herein. It should be understood that teachings herein may be incorporated into any of the fans described in any of the above-referenced patents, publications, or patent applications
A fan blade or airfoil may include one or more upper air fences and/or one or more lower air fences at any suitable position(s) along the length of the fan blade or airfoil. Merely exemplary air fences are described in U.S. Pat. Pub. No. 2011/0081246, entitled “Air Fence for Fan Blade,” published Apr. 7, 2011, the disclosure of which is incorporated by reference herein. Alternatively, any other suitable type of component or feature may be positioned along the length of a fan blade or airfoil; or such components or features may simply be omitted.
The outer tip of a fan blade or airfoil may be finished by the addition of an aerodynamic tip or winglet. Merely exemplary winglets are described in U.S. Pat. No. 7,252,478, entitled “Fan Blade Modifications,” issued Aug. 7, 2007, the disclosure of which is incorporated by reference herein. Additional winglets are described in U.S. Pat. No. 7,934,907, entitled “Cuffed Fan Blade Modifications,” issued May 3, 2011, the disclosure of which is incorporated by reference herein. Still other exemplary winglets are described in U.S. Pat. No. D587,799, entitled “Winglet for a Fan Blade,” issued Mar. 3, 2009, the disclosure of which is incorporated by reference herein. In some settings, such winglets may interrupt the outward flow of air at the tip of a fan blade, redirecting the flow to cause the air to pass over the fan blade in a perpendicular direction, and also ensuring that the entire air stream exits over the trailing edge of the fan blade and reducing tip vortex formation. In some settings, this may result in increased efficiency in operation in the region of the tip of the fan blade. In other variations, an angled extension may be added to a fan blade or airfoil, such as the angled airfoil extensions described in U.S. Pat. No. 8,162,613, entitled “Angled Airfoil Extension for Fan Blade,” issued Apr. 24, 2012, the disclosure of which is incorporated by reference herein. Other suitable structures that may be associated with an outer tip of an airfoil or fan blade will be apparent to those of ordinary skill in the art. Alternatively, the outer tip of an airfoil or fan blade may be simply closed (e.g., with a cap or otherwise, etc.), or may lack any similar structure at all.
The interface of a fan blade and a fan hub may also be provided in a variety of ways. For instance, an interface component is described in U.S. Pat. No. 8,147,204, entitled “Aerodynamic Interface Component for Fan Blade,” issued Apr. 3, 2012, the disclosure of which is incorporated by reference herein. In addition, or in the alternative, the fan blade may include a retention system that couples the tip of a fan blade to an attachment point on the fan hub via a cable running through the fan blade, such as that disclosed in U.S. Pat. Pub. No. 2011/0262278, published Oct. 27, 2011. Alternatively, the interface of a fan blade and a fan hub may include any other component or components, or may lack any similar structure at all.
Fans may also include a variety of mounting structures. For instance, a fan mounting structure is disclosed in U.S. Pat. No. 8,152,453, entitled “Ceiling Fan with Angled Mounting,” issued Apr. 10, 2012, the disclosure of which is incorporated herein. Of course, a fan need not be mounted to a ceiling or other overhead structure, and instead may be mounted to a wall or to the ground. For instance, a fan may be supported on the top of a post that extends upwardly from the ground. Examples of such mounting structures are shown in U.S. Design Pat. No. D635,237, entitled “Fan with Ground Support,” issued Mar. 29, 2011, the disclosure of which is incorporated by reference herein; U.S. Design Pat. No. D641,075, entitled “Fan with Ground Support and Winglets,” issued Jul. 5, 2011, the disclosure of which is incorporated by reference herein; and U.S. Pat. App. No. 61/720,077, entitled “Fan Mounting System,” filed Oct. 30, 2012, the disclosure of which is incorporated by reference herein. Alternatively, any other suitable mounting structures and/or mounting techniques may be used in conjunction with embodiments described herein.
It should also be understood that a fan may include sensors or other features that are used to control, at least in part, operation of a fan system. For instance, such fan systems are disclosed in U.S. Pat. No. 8,147,182, entitled “Ceiling Fan with Concentric Stationary Tube and Power-Down Features,” issued Apr. 3, 2012, the disclosure of which is incorporated by reference herein; U.S. Pat. No. 8,123,479, entitled “Automatic Control System and Method to Minimize Oscillation in Ceiling Fans,” issued Feb. 28, 2012, the disclosure of which is incorporated by reference herein; U.S. Pat. Pub. No. 2010/0291858, entitled “Automatic Control System for Ceiling Fan Based on Temperature Differentials,” published Nov. 18, 2010, the disclosure of which is incorporated by reference herein; U.S. Provisional Patent App. No. 61/165,582, entitled “Fan with Impact Avoidance System Using Infrared,” filed Apr. 1, 2009, the disclosure of which is incorporated by reference herein; and U.S. Pat. App. No. 61/720,679, entitled “Integrated Thermal Comfort Control System Utilizing Circulating Fans,” filed Oct. 31, 2012, the disclosure of which is incorporated by reference herein. Alternatively, any other suitable control systems/features may be used in conjunction with embodiments described herein.
In some settings, it may be desirable to replicate or approximate the function of a winglet in a component that may be located at a position on a fan blade other than at the free end of the fan blade. For instance, such components are disclosed in U.S. Pat. Pub. No. 2011/0081246, entitled “Air Fence For Fan Blade,” published Apr. 7, 2011, the disclosure of which is incorporated by reference herein. Such a component may provide an effect on fan efficiency similar to the effect provide by a winglet, albeit at one or more additional regions of the fan blade. In particular, such a component or accessory may serve as an aerodynamic guide or air fence, interrupting slippage of air along the length or longitudinal axis of the fan blade; and redirecting the air flow to a direction perpendicular to the longitudinal axis of the fan blade, above and/or below the fan blade.
In some ceiling fans, flat planar blades are used by inclining the blades at an angle of approximately ten to twenty degrees from the horizontal to displace airflow in a downward direction. These flat blades might not be aerodynamically efficient in some settings. Accordingly, to move a given volume of air, the fan must operate at a higher speed, thereby consuming more electricity. In addition, these flat blades might be manufactured from wood or fiberboard, harvested from trees, such as Monterey Pine, which typically take 25-30 years to reach maturity. Since the regrowth time of the raw materials may exceed the lifespan of the ceiling fan, continued production in this manner is not an environmentally sustainable practice.
While flat planar blades have been used, attempts have been made to improve upon ceiling fan blade designs. For example, Parker, et al, U.S. Pat. No. 6,039,541, issued Mar. 21, 2000, describes a ceiling fan blade that includes the SD7032, GM15, MA409, and Hibbs 504 airfoils. Airfoils of this type may operate with higher coefficients of lift versus angle of attack at Reynolds numbers greater than 100,000. In the instance of a fan blade with a chord length of 10.16 centimeters (4 inches) and blade span with the root located 22.5 centimeters (9 inches) from the center of rotation and a tip located 76.2 centimeters (30 inches) from the center of rotation, operating at 50 rotations per minute may experience Reynolds numbers ranging from 8,000 at the root to 28,000 at the tip. While at 200 rotations per minute, the fan blade may experience Reynolds numbers ranging from 33,000 at the root to 110,000 at the tip. At speeds below 180 rotations per minute, the entire blade may experience Reynolds numbers less than 100,000. Accordingly, the airfoils described by Parker, et al. may operate below their optimal performance under the majority of operating conditions for the ceiling fan. Furthermore, airfoil blades of the types disclosed in Parker, et al. may increase manufacturing complexity since the airfoil thickness has a teardrop profile and varies substantially from leading edge to trailing edge. In some instances, to create this teardrop profile the blade must be manufactured by plastic injection molding or, alternatively, machined from a flat sheet material, which may result in significant wastage. Thus, a need exists for an improved blade design that offers optimal airflow performance at the low Reynolds numbers experienced by a ceiling fan and is capable of being manufactured by simple techniques using sustainable materials.
While several systems and methods have been made and used for ceiling fan blades, it is believed that no one prior to the inventors has made or used the invention described in the appended claims.
While the specification concludes with claims which particularly point out and distinctly claim this technology, it is believed this technology will be better understood from the following description of certain examples taken in conjunction with the accompanying drawings, in which like reference numerals identify the same elements and in which:
The drawings are not intended to be limiting in any way, and it is contemplated that various embodiments of the technology may be carried out in a variety of other ways, including those not necessarily depicted in the drawings. The accompanying drawings incorporated in and forming a part of the specification illustrate several aspects of the present technology, and together with the description serve to explain the principles of the technology; it being understood, however, that this technology is not limited to the precise arrangements shown.
DETAILED DESCRIPTIONThe following description of certain examples of the technology should not be used to limit its scope. Other examples, features, aspects, embodiments, and advantages of the technology will become apparent to those skilled in the art from the following description, which is by way of illustration, one of the best modes contemplated for carrying out the technology. As will be realized, the technology described herein is capable of other different and obvious aspects, all without departing from the technology. Accordingly, the drawings and descriptions should be regarded as illustrative in nature and not restrictive.
I. Exemplary Fan Overview
Referring to
Support (20) is configured to be coupled to a surface or other structure at a first end such that fan (10) is substantially attached to the surface or other structure. Support (20) of the present example comprises an elongate metal tube-like structure that couples fan (10) to a ceiling, though it should be understood that support (20) may be constructed and/or configured in a variety of other suitable ways as will be apparent to one of ordinary skill in the art in view of the teachings herein. In one merely exemplary version, support (20) is configured to couple to an electrical junction box (not shown) located within or on a ceiling. With support (20) comprising an elongate metal tube, wires or other power supply or control members are extended through support (20) to motor (30). By way of example only, support (20) need not be coupled to a ceiling or other overhead structure, and instead may be coupled to a wall or to the ground. For instance, support (20) may be positioned on the top of a post that extends upwardly from the ground. Alternatively, support (20) may be mounted in any other suitable fashion at any other suitable location. This includes, but is not limited to, the teachings of the patents, patent publications, or patent applications cited herein. By way of example only, support (20) may be configured in accordance with the teachings of U.S. Pat. Pub. No. 2009/0072108, entitled “Ceiling Fan with Angled Mounting,” published Mar. 19, 2009, the disclosure of which is incorporated by reference herein. As yet another alternative, support (20) may have any other suitable configuration.
As shown in
In some versions, motor (30) comprises an AC induction motor having a drive shaft, though it should be understood that motor (30) may alternatively comprise any other suitable type of motor (e.g., a permanent magnet brushless DC motor, a brushed motor, an inside-out motor, etc.). In the present example, motor (30) is fixedly coupled to support (20) and is configured to rotate fan blades (50) relative to support (20) such that air is propelled by fan (10) away from the structure to which support (20) is coupled. In an alternative version, shown in
In the present example, fan (10) further includes a top cover (34). Top cover (34) comprises a dome-shaped component configured to enclose the top of motor (30). Top cover (34) of the present example is attached to support (20) to form a dome over the top of motor (30) when motor (30) is coupled to support (20). In some versions, top cover (34) is threadably coupled to support (20). In other versions, top cover (34) may be integrally formed with support (20), coupled via fasteners (not shown), or otherwise attached to support (20) and/or motor (30). When fan blades (50) of the example shown in
Fan blades (50) of the example shown in
While some merely exemplary features of fan (10) have been described herein, it should be understood that fan (10) may have other features, components, and/or configurations as will be apparent to one of ordinary skill in the art in view of the teachings herein.
II. Exemplary Fan Blades
A single fan blade (50) is shown plan form in
Fan blade (50) also includes a transition region (60) extending from root end (52), shown best in
Of course, it should be understood that other configurations for transition region (60) and/or other regions of fan blade (50) may be used. For instance, if root end (52) omits a domed sector, then fan blade (50) may omit first portion (62) and, in some versions, inflection portion (64), having only second portion (66) transition to root airfoil profile (100) directly. Still further constructions for transition region (60), etc., will be apparent to one of ordinary skill in the art in view of the teachings herein.
Referring now to
Fan blade (50) of the present example is manufactured from thin sheets of material laminated together. For instance, fan blade (50) may be constructed by combining individual sheets with adhesive between each layer and forcing the sheets together under pressure in a shaped mold to form fan blade (50) shown in
III. Exemplary Alternative Fan
A circular bottom cover (416) includes a plurality of upwardly projecting L-shaped tabs (418) disposed about the circumference of bottom cover (416) and a central lens (419). Lens (419) may be constructed in accordance with lens (48) described above. Bottom cover (416) is configured to couple to a bottom portion of fan blades (450) via tabs (418) inserting into recesses (not shown) formed in fan blades (450) and then being rotated such that an axial projection from each tab locks into the recesses. Accordingly, when bottom cover (416) is coupled to fan blades (450), a substantially smooth lower surface for fan (400) is formed. Of course it should be understood that bottom cover (416) may couple to fan blades (450) through other attachment members, such as screws, bolts, clips, clamps, straps, resilient tabs, etc. In addition, or in the alternative, bottom cover (416) may be directly coupled to motor (420). Fan (400) may be further configured in accordance with the teachings of fan (10) described above or in any other manner as will be apparent to one of ordinary skill in the art in view of the teachings herein.
Referring now to
Root end (452) is further includes a recessed ledge (458) and an outer lip (460) disposed on opposing ends of root end (452). As shown in
Fan blade (450) of the present example is manufactured by a thermoplastic resin that is injected into a mold for fan blade (450) to achieve the desired profile. Alternatively, fan blade (450) may be formed from thin sheets of material laminated together and anchored to a thermoplastic or other material root end (452). For instance, fan blade (450) may be constructed by combining individual sheets with adhesive between each layer and forcing the sheets together under pressure in a shaped mold to form fan blade (450) shown in
It should be appreciated that any patent, publication, or other disclosure material, in whole or in part, that is said to be incorporated by reference herein is incorporated herein only to the extent that the incorporated material does not conflict with existing definitions, statements, or other disclosure material set forth in this disclosure. As such, and to the extent necessary, the disclosure as explicitly set forth herein supersedes any conflicting material incorporated herein by reference. Any material, or portion thereof, that is said to be incorporated by reference herein, but which conflicts with existing definitions, statements, or other disclosure material set forth herein will only be incorporated to the extent that no conflict arises between that incorporated material and the existing disclosure material.
Having shown and described various embodiments of the present invention, further adaptations of the methods and systems described herein may be accomplished by appropriate modifications by one of ordinary skill in the art without departing from the scope of the present invention. Several of such potential modifications have been mentioned, and others will be apparent to those skilled in the art. For instance, the examples, embodiments, geometrics, materials, dimensions, ratios, steps, and the like discussed above are illustrative and are not necessarily required. Accordingly, the scope of the present invention should be considered in terms of the following claims and is understood not to be limited to the details of structure and operation shown and described in the specification and drawings.
Claims
1. A fan blade configured to mount to a rotating fan hub, the fan blade comprising:
- a. a root end configured to couple with the rotating fan hub, wherein a profile of the root end comprises a substantially convex top surface and a substantially concave domed sector;
- b. a blade region, wherein a profile of the blade region comprises a substantially convex top surface and bottom surface;
- c. a transition region extending between the root end and the blade region, wherein the transition region comprises a profile which transitions the root end profile to the blade region profile;
- d. a leading edge;
- e. a trailing edge; and
- f. a tip, wherein the leading edge and trailing edge terminate into the tip.
2. The fan blade of claim 1, wherein the root end comprises an arcuate cutout.
3. The fan blade of claim 2, wherein the domed sector is configured to terminate into a region which is parallel to a plane of rotation of the fan blade at a position proximal to the arcuate cutout.
4. The fan blade of claim 3, wherein the transition portion comprises a first potion, an inflection portion, and a second potion.
5. The fan blade of claim 4, wherein the first portion comprises an extension of the concave domed sector of the root end which terminates at the inflection portion.
6. The fan blade of claim 5, wherein the inflection portion comprises a quasi-parabolic shaped portion that extends from the leading edge to the trailing edge and transitions the fan blade from the extension of the concave domed sector of the first portion to a planar portion.
7. The fan blade of claim 6, wherein the second portion extends from the inflection portion and the planar portion to the profile of the blade region.
8. The fan blade of claim 7, wherein the top surface of the profile of the blade region comprises:
- a first top convex curvature proximal to the second portion of the transition region, and a second top convex curvature proximal to the tip.
9. The fan blade of claim 8, wherein the bottom surface of the profile of the blade region comprises a first bottom convex curvature proximal to the second portion of the transition region, and a second bottom convex curvature proximal to the tip.
10. The fan blade of claim 9, wherein the top surface of the blade region transitions from the first top convex curvature to the second top convex curvature along a length of the blade region.
11. The fan blade of claim 10, wherein the bottom surface of the blade region transitions from the first bottom convex curvature to the second bottom convex curvature along the length of the blade region.
12. The fan blade of claim 11, wherein the bottom surface of the blade region slopes upward along the length of the blade region.
13. The fan blade of claim 12, wherein the top surface of the blade region slopes upward along the length of the blade region.
14. The fan blade of claim 13, wherein the leading edge is located at a position higher than a position of the trailing edge.
15. The fan blade of claim 14, wherein the tip is curved.
16. A fan assembly comprising:
- a. a fan motor;
- b. a fan hub, wherein the fan hub is attached to the fan motor; and
- c. the fan blade of claim 14, wherein the fan blade is one of a plurality of similar fan blades mounted to the fan hub.
17. A fan blade configured to mount to a rotating fan hub, the fan blade comprising:
- a. a root end, wherein the root end comprises: i. a root end profile comprising a concave bottom surface and a convex top surface, ii. a cutout on the bottom surface configured to receive a bottom surface of the fan hub, iii. a plurality of holes configured to allow the root end to be coupled to the rotating fan hub, and iv. a cutout on the top surface configured to receive a top surface of the fan hub;
- b. a blade region, wherein a profile of the blade region comprises a substantially convex top surface and bottom surface; and
- c. a transition region located between the root end and the blade region, wherein a profile of the transition region transitions the profile of the root end into the profile of the blade region.
18. The fan blade of claim 17, wherein the relief on the top surface of the root end is substantially square in shape.
19. The fan blade of claim 18, wherein the bottom surface of the root end is configured to terminate into a region which is parallel to a plane of rotation of the fan blade at a position proximal to the cutout.
20. A fan assembly, wherein the fan assembly comprises:
- a. a fan motor;
- b. a fan hub, wherein the fan hub is coupled to the fan motor; and
- c. a plurality of fan blades, wherein each one of the fan blades of the plurality of fan blades comprises: i. a root end capable of being coupled to the rotating fan hub, wherein a profile of the root end comprises a substantially convex top surface and a substantially concave domed sector, ii. a blade region, wherein a profile of the blade region comprises a substantially convex top surface and bottom surface, and iii. a transition region extending between the root end and the blade region, wherein the transition region comprises a profile which transitions the root end profile to the blade region profile.
Type: Application
Filed: Jan 17, 2013
Publication Date: Jul 25, 2013
Applicant: DELTA T CORPORATION (Lexington, KY)
Inventor: DELTA T CORPORATION (Lexington, KY)
Application Number: 13/743,456
International Classification: F01D 5/02 (20060101);