阅读说明：本技术 吊扇叶片 (Ceiling fan blade ) 是由 博比·尼尔·诺伍德 查尔斯·威廉·博特金 于 2019-07-10 设计创作，主要内容包括：一种吊扇或吊扇的叶片,可包括用于旋转叶片的风扇马达。叶片可包括翼型体,该翼型体具有在前缘和后缘之间延伸的外表面,以及根部和顶端。叶片可以分成三个不同的截面,包括作为提升截面的第一截面,作为平坦截面的第二截面,以及作为第一截面和第二截面之间的过渡区段的第三截面。(A blade for a ceiling fan or fan may include a fan motor for rotating the blade. The blade may comprise an airfoil body having an outer surface extending between a leading edge and a trailing edge, and a root portion and a tip portion. The blade may be divided into three different sections, including a first section that is a lifting section, a second section that is a flat section, and a third section that is a transition section between the first and second sections.)

1. A blade for a ceiling fan having a fan motor for rotating at least one blade iron, the blade comprising:

an airfoil body having an outer surface extending between a leading edge and a trailing edge to define a chordwise direction, and the outer surface is divided into an upper surface and a lower surface, and the outer surface extends between a root and a tip to define a spanwise direction; and

a blade iron base disposed on the root;

wherein the airfoil body comprises at least three different cross-sections in the spanwise direction: a first cross-section comprising a flat lower surface and having a raised cross-section; a second cross-section comprising a planar lower surface and a planar upper surface; and a third cross-section located between the first cross-section and the second cross-section and transitioning from the first cross-section to the second cross-section.

2. The blade of claim 1, wherein the first cross-section comprises a first angle of attack and the second cross-section comprises a second angle of attack to the first cross-section such that the airfoil body twists about the third cross-section.

3. The blade of claim 1, wherein the lifting section is one of a flat-bottomed airfoil, a symmetric airfoil, a semi-symmetric airfoil, or a lower cambered airfoil.

4. The blade of claim 3, wherein the lifting section comprises a flat-bottom airfoil.

5. The blade of claim 1, wherein the tip comprises a front surface having a convex shape.

6. The blade of claim 5, wherein the root portion comprises a flat trailing surface.

7. The blade of claim 1, wherein said blade iron base is disposed on an upper surface of said airfoil body at said root portion.

8. The blade of claim 7, wherein said blade iron base is a washer.

9. The blade of claim 1, wherein said blade iron base is provided on a lower surface of said airfoil body.

10. The blade of claim 1, wherein the airfoil body further comprises a fourth cross-section at the root portion, the fourth cross-section comprising a planar lower surface and a planar upper surface.

11. The blade of claim 10, further comprising a fifth cross-section between and transitioning between the first cross-section and the fourth cross-section.

Technical Field

The invention relates to a ceiling fan blade.

Background

Ceiling fans are machines that are typically suspended from a structure for moving a volume of air around an area. The ceiling fan includes a motor suspended from and electrically coupled to the structure, the motor having a rotor and a stator. A set of blades is mounted to the rotor such that the blades are rotatably driven by the rotor and can be disposed in an angled orientation to move a volume of air around the area. As energy costs become more important, there is a need to improve the efficiency of ceiling fan operation.

Disclosure of Invention

In one aspect, the present disclosure is directed to a blade for a ceiling fan having a fan motor that rotates at least one blade iron. The blade includes an airfoil body having an outer surface extending between a leading edge and a trailing edge to define a chordwise direction, and the outer surface is divided into an upper surface and a lower surface, and the outer surface extends between a root and a tip to define a spanwise direction. The root part is provided with a blade iron base. The airfoil body comprises at least three different cross sections in the spanwise direction: a first cross-section comprising a flat lower surface and a raised cross-section; a second cross-section comprising a planar lower surface and a planar upper surface; and a third cross-section located between the first cross-section and the second cross-section and transitioning from the first cross-section to the second cross-section.

In another aspect, the present disclosure is directed to a ceiling fan assembly comprising a motor including a rotatable rotor and a stationary stator, wherein the stator is configured to drive the rotor. At least one blade coupled to the rotor and having an airfoil body including an outer surface extending between a leading edge and a trailing edge to define a chordwise direction and dividing the outer surface into an upper surface and a lower surface, and the outer surface extending between a root and a tip to define a spanwise direction. The root part is provided with a blade iron base. The airfoil body comprises at least three different cross sections in the span wise direction: a first cross-section comprising an airfoil cross-section; a second cross-section comprising a planar lower surface and a planar upper surface; and a third cross-section located between the first cross-section and the second cross-section and transitioning from the first cross-section to the second cross-section.

In yet another aspect, the present disclosure is directed to a blade for a ceiling fan, the blade comprising an airfoil body having an outer surface extending between a leading edge and a trailing edge to define a chordwise direction and dividing the outer surface into an upper surface and a lower surface, and the outer surface extending between a root and a tip to define a spanwise direction. The airfoil body comprises at least three different cross sections in the spanwise direction: a first cross-section comprising an airfoil cross-section; a second cross-section comprising a planar upper surface and a planar lower surface; a third cross-section located between and transitioning between the first cross-section and the second cross-section.

Drawings

In the drawings:

FIG. 1 is a schematic view of a structure having a ceiling fan including a set of blades suspended from the structure.

FIG. 2 is a top view of one blade from the set of blades or FIG. 1 having different segments as first, second and third segments shown as split lines.

FIG. 3 is a cross-sectional view of a first section of the blade of FIG. 2 taken along section III-III.

FIG. 4 is a cross-sectional view of a second section of the blade of FIG. 2 taken along section IV-IV.

FIG. 5 is a cross-sectional view of a third section of the blade of FIG. 2 taken along section V-V.

FIG. 6 is a side view of the blade better illustrating the first section of FIG. 3, the second section of FIG. 4, and the third section of FIG. 5.

FIG. 7 is a perspective side view of the blade depicting the contours of the first section of FIG. 3, the second section of FIG. 4, and the third section of FIG. 5.

FIG. 8 is a top view of a fan blade having five exemplary sections as indicated by the separation lines.

FIG. 9 is a cross-sectional view of a fan blade having a flat bottom airfoil shape.

FIG. 10 is a cross-sectional view of a fan blade having a symmetrical airfoil shape.

FIG. 11 is a cross-sectional view of a fan blade having a semi-symmetrical airfoil shape.

FIG. 12 is a cross-sectional view of a fan blade having a leading airfoil shape with deep camber.

FIG. 13 is a cross-sectional view of a fan blade having a trailing airfoil shape.

FIG. 14 is a cross-sectional view of a fan blade having a lower cambered airfoil shape with a uniform thickness.

FIG. 15 is a cross-sectional view of a fan blade having a flat upper surface, a flat lower surface, a flat leading edge, and a flat trailing edge.

FIG. 16 is a cross-sectional view of a fan blade having a varying angle of attack to form a twist.

Detailed Description

The present disclosure relates to ceiling fans and fan blades, which may be used in residential and commercial applications, for example. These applications may be indoor, outdoor, or both. Although this description is primarily directed to residential ceiling fans, it is also applicable to any environment that utilizes a fan or cooling area that utilizes air movement.

As used herein, the term "set" or "collection of elements" can be any number of elements, including only one element. All directional references (e.g., radial, axial, proximal, distal, upper, lower, upward, downward, left, right, lateral, front, rear, top, bottom, above, below, vertical, horizontal, clockwise, counterclockwise, upstream, downstream, forward, rearward, etc.) are only used for identification purposes to aid the reader's understanding of the present disclosure, and do not create limitations, particularly as to the position, orientation, or use of aspects of the present disclosure described herein. Connection references (e.g., attached, coupled, connected, and joined) are to be construed broadly and may include intermediate members between a collection of elements and relative movement between elements unless otherwise indicated. Thus, joinder references do not necessarily infer that two elements are directly connected and in fixed relation to each other. The exemplary drawings are for illustrative purposes only, and the dimensions, locations, order, and relative sizes reflected in the drawings may vary.

Referring now to FIG. 1, a ceiling fan 10 is suspended from a structure 12. In a non-limiting example, the ceiling fan 10 may include one or more ceiling fan components including a hanger 14, a canopy 16, a downrod 18, a motor adapter 20, a motor housing 22 at least partially enclosing a motor 24 having a rotor 26 and a stator 28, a light kit 30, and a set of blade irons 32. In further non-limiting examples, the ceiling fan 10 may include one or more of a controller, a wireless receiver, a ball holder, a hanger ball, a light glass, a lantern, a spindle, a tip, a switch housing, a blade fork, a blade tip or cap, or other ceiling fan components. A set of blades 34 may extend radially from the ceiling fan 10 and may rotate to drive a quantity of fluid (such as air). The vanes 34 may be operatively coupled to the motor 24 at the rotor 26. The blades 34 may include a set of blades 34 having any number of blades, including only one blade.

The structure 12 may include an exemplary ceiling 40 from which the ceiling fan 10 is suspended and a set of walls 42. It should be understood that the structure 12 is shown schematically and by way of example only, and may include any suitable building, structure, home, commercial or other environment where moving air with a ceiling fan is suitable or desirable. A power source 44 may be disposed in the structure 12 and may be electrically coupled to the ceiling fan 10 to provide power to the ceiling fan 10 and the motor 24 therein. It is also contemplated that the power source may come from somewhere other than the structure 12, such as a battery or generator in non-limiting examples.

The wired controller 46 may be electrically coupled to the power source 44 to control operation of the ceiling fan 10 via the power source 44. Similarly, a wired controller 46 is communicatively coupled to the ceiling fan 10, the wired controller being configured to control the operation of the ceiling fan 10. Non-limiting examples of control of the ceiling fan 10 may include fan speed, fan direction, or light operation. In addition, the wireless controller 48, alone or in conjunction with the wired controller 46, may be communicatively coupled to a controller or wireless receiver in the ceiling fan 10 to control the operation of the ceiling fan 10. In an alternative example, it is further contemplated that the ceiling fan is operated only by the wireless controller 48 and is not operatively coupled with the wired controller 46.

Referring now to FIG. 2, a single fan blade 34 includes a body 60 having first and second upper surfaces 62, 64, a root 66, and a tip 68, and extending between first and second sides 70, 72, which may be, for example, leading and trailing edges, depending on the direction of rotation of the blade. In one example, the upper surface 62 may face the ceiling 40, while the lower surface 64 may face the floor of the structure 12. The apex 68 may include a front surface between the first upper surface 62 and the second lower surface 64, e.g., having a convex shape. When mounted to the ceiling fan 10, the root 66 may be proximal to the motor 24, while the tip 68 may be distal. For example, the root 66 may have a rear surface between the first upper surface 62 and the second lower surface 64 that is flat. The tip 68 has a chord (chord) that is greater or longer than the root 66 such that the chord length increases between the first side 70 and the second side 72 and may increase continuously from the root 66 to the tip 68. In one example, the rate of increase of the chord length may be constant. A spanwise axis 74 may be defined as extending between the root 66 and the tip 68. In one non-limiting example, the span axis 74 may be defined equidistantly between the first and second sides 70, 72 extending between the root 66 and the tip 68. The chordwise axis 82 may define a chordwise direction extending between the first and second sides 70, 72, and may be disposed orthogonal to the spanwise axis 74, for example. In one example, the body 60 may increase in length as measured along the span axis 74 such that the blade widens extending from the root 66 to the tip 68. In other examples, the chord length may vary along the span axis 74 such that it may vary, continuously increase, or continuously decrease.

Blade iron mount 76 may be mounted to and extend from first upper surface 62 and may include a flat mounting surface 78. The blade iron mount 76 may be a washer, in non-limiting examples, and may be made of a substantially rigid material suitable for mounting the blade 34 to the motor 24 while dampening vibrations between the blade 34 and the motor 24, such as foam, neoprene, rubber, polymer, polyurethane, elastomer, composite, or plastic, in non-limiting examples. A set of mounting holes 80, shown as three mounting holes 80, may be provided in the mounting surface 78. In one example, the set of mounting holes 80 may be threaded, configured to threadably receive a fastener, such as a screw, to secure the blade 34 to the motor 24.

The blade 34 may be divided into a first section 90 having a first cross-section or profile, a second section 92 having a second cross-section or profile, and a third section 94 having a third cross-section or profile. In one example, the first section 90 may be symmetrical, such as symmetrical about the spanwise axis 74 or the chordwise axis 82. The first segment 90 may be located at the root 66 and extend from the root 66, along the span axis 74 toward the tip 68.

The second section 92 may be disposed at the tip 68, extending toward the root 66. In one non-limiting example, the second section 92 having the second profile with the planar lower surface 64 and the planar upper surface 62 may be located only at the apex 68, the apex 68 including the planar upper surface 62 and the lower surface 64. Alternatively, it is contemplated that the second segment 92 occupies a larger span portion of the blade 34.

Referring now to fig. 3, which takes the section III-III of fig. 2, the cross-section of the first section 90 includes an airfoil profile (airfoil profile), shown as a flat-bottomed airfoil, including a flat second lower surface 64, and an asymmetric convex first upper surface 62. The first section 90 may include a first maximum thickness 104 of the airfoil profile of the first section 90, the first maximum thickness 104 being defined between the first upper surface 62 and the second lower surface 64 along the first section 90, which may be measured orthogonally to the first upper surface 62, the second lower surface 64, or both, or may be measured relative to a chord line defined by the airfoil cross-section, for example. It should be appreciated that, due to the airfoil cross-sectional shape, the thickness between the first upper surface 62 and the second lower surface 64 may vary between the first side edge 70 and the second side edge 72, or the first maximum thickness 104 may be positioned differently than shown based on the particular shape of the airfoil cross-section.

The first section 90 may include a cross-section, which may be a lift cross-section or an airfoil cross-section. The lifting section or airfoil section may be any section or profile shaped to generate lift, for example, in at least one rotational direction, and may include, in non-limiting examples, any airfoil section shape, such as a flat-bottomed airfoil, a symmetric airfoil, a semi-symmetric airfoil, a lower cambered airfoil, or any other airfoil shape, such as an airfoil shape having a forward camber, a rear camber, no camber, a varying or constant thickness, a large or small thickness, or any other suitable aerodynamic airfoil characteristic that forms a lifting section. Such aerodynamic airfoil features may be any feature suitable for increasing the operating efficiency of the ceiling fan 10 due to a reduced aerodynamic drag or turbulence, a profile utilizing bernoulli's principle, or, in a non-limiting example, a profile that increases boundary layer attachment along at least a portion of the first upper surface 62 or the second lower surface 64.

It should be understood that while the flat bottom airfoil shape of the first section 90 includes a generally lower camber, any camber, such as a deep camber or any camber therebetween, is contemplated. Further, although not shown, it is contemplated that the camber may include a small or large thickness, or alternatively a reflective trailing edge.

The blades 34 may be oriented at an angle of attack (angle of attack)100, wherein the blades 34 are disposed at an angle relative to a horizontal plane 102 such that the second lower surface 64 is offset from the horizontal, wherein the lower surface 64 opposes air during rotation of the blades 34. Arranging the blades 34 at an angle of attack 100 may move a certain amount of air during the rotational motion of the fan blades 34.

Referring now to fig. 4, which takes section IV-IV of fig. 2, the second section 92 includes a section or profile having a planar first upper surface 62 and a planar second lower surface 64. A second maximum thickness 106 may be defined between the first upper surface 62 and the second lower surface 64 at the second section 92. For example, the second maximum thickness 106 may be measured orthogonally to the first upper surface 62, the second lower surface 64, or both. The thickness may be constant along a majority of the second section 92 because the first upper surface 62 and the second lower surface 64 may be flat and parallel to each other (except for the first side edge 70 and the second side edge 72 being rounded to provide a curved transition between the upper surface 62 and the lower surface 64). The second maximum thickness 106 may be less than the first maximum thickness 104, which is considerable such that the aerodynamic airfoil shape of the first section 90 provides an increased thickness relative to the thickness of the second section 92 including the flat upper and lower surfaces 62, 64. It should be understood that the first section 90 having the greater first maximum thickness 104 is visible behind the second section 92 in fig. 4.

Additionally, the blades 34 at the second section 92 may be arranged at an angle of attack 100, while it is contemplated that the second section 92 may not be arranged at an angle of attack 100 or may be arranged at an angle of attack 100 that is different than the angle of attack 100 of the first section 90. In another non-limiting example, the angle of attack 100 may vary along the span axis 74, as best shown in FIG. 14.

Referring now to FIG. 5, which takes section V-V of FIG. 2, the third section 94 includes a transition section from the first section 90 to the second section 92. The third section 94 may include a third maximum thickness 108 that is less than the first maximum thickness 104 of fig. 3, but greater than the second thickness 106 of fig. 4, thereby creating a transition between the first section 90 and the second section 92. For example, the third maximum thickness 108 may be measured orthogonally to the first upper surface 62, the second lower surface 64, or both. The first section 90 is visible behind the third section 94, as shown in fig. 5. The thickness of the airfoil section along the third section 94 may vary, thereby creating the shape of the airfoil section. It should be appreciated that the third section 94 includes an airfoil shape having a camber that is less than the camber of the first section 90, as it transitions to the second section 92 without camber.

At the tip 68, the blade 34 includes a flat upper surface 62 and a flat lower surface 64, with the flat lower surface 64 extending completely along the span of the blade 34. Thus, when a user views the blade 34 from the bottom or the tip 68 along the blade 34, the airfoil shape is not visible, nor is it easily identifiable. Moreover, the second section 92, in combination with the flat second lower surface 64 of the first section 90, provides the fan blade 34 with the traditional aesthetics of a plain bottom surface 64 when the fan blade 34 transitions into the airfoil section 90, which is preferred by consumers, whereas an entire fan blade having an airfoil cross-section does not. The third section 94 provides a smooth transition between the first section 90 and the second section 92, which reduces aerodynamic losses while providing an aesthetically pleasing appearance to the consumer between the first section 90 and the second section 92.

Referring now to FIG. 6, for example, the first segment 90 may extend at least 80% of the span from the root 66 to the tip 68, or may be about 90% or 95% of the span, in other non-limiting examples, or any value between 80% span and 95% span. It should be understood that the first section 90 may occupy a smaller portion of the span than those described, such as less than 80% span or greater than 95% span.

In a non-limiting example, the second section 92 may be about 3-10% or 5-10% of the span extending along the span axis 74. It should be understood that other ranges or sizes for the second section are contemplated, such as, for example, ranges or sizes less than 3% span or greater than 10% span. In one example, the second section 92 may be symmetrical along the chordwise axis 82. The third section 94 may be positioned between the first section 90 and the second section 92, and may transition from the first section 90 to the second section 92. The third section 94 may include the remainder of the blade 34 not occupied by the first and second sections 90, 92, such as 5-15% span in one non-limiting example. It should be understood that other ranges or sizes for the third section 94 are contemplated, for example, less than 5% span or greater than 15% span.

Referring now to FIG. 7, the blade 34 may include different profiles for the different sections 90, 92, 94. For example, the airfoil profile of the first section 90 may include a convex circular surface for the upper surface 62. The third section 94 transitioning between the first and second sections 90, 92 may include a slight taper relative to the upper surface 62 parallel to the plane of the flat lower surface 64. Further, the upper surface 62 at the third section 94 may include a convex curve to transition between the first section 90 and the second section 92. Alternatively, it is contemplated that the upper surface 62 of the third section 94 may be concave, flat, linear, discrete, stepped, or adapted for any variation in the transition between the first section 90 and the second section 92.

In operation, the lift or airfoil section of the first section 90 generates an increasing downward force imparted to the air passing along the blade 34, which may be the result of the lift generated by the blade shape. The increased downward force increases the total volume of air moved by the fan blade relative to a blade without the lift or airfoil section of the first section 90. Utilizing angle of attack 100 in combination with a lift or airfoil section may further increase the total volume of air moved by fan blade 34 while requiring less total energy cost for the flow generated by blade 34 relative to a conventional fan blade that is flat along the entire length of the blade. Thus, the described blade 34 provides aerodynamic and efficiency improvements along the first section 90 of the blade 34. In one example, such an airfoil shape may improve overall performance of the total flow by 30% or more. In one example, the blades 34 may increase the maximum air velocity by 7% -40% relative to blades having upper and lower surfaces that are flat along the extent of the blade. In addition, an increase of the maximum air velocity of more than 40% is possible. Similarly, the vanes 34 may increase flow by 5% to 35% relative to vanes having completely flat upper and lower surfaces. Additional increases in flow rate of greater than 35% are possible.

Referring now to FIG. 8, the replacement blade 134 has five different sections 190, 192, 194, 196, 198 and has two transition sections 194, 196 relative to the three sections 90, 92, 94 and the single transition section 94 of FIG. 2. Similar to FIG. 2, the blade 134 may include a body 160, the body 160 including a first upper surface 162 and a second lower surface 164 extending between a root 166 and a tip 168 to define a span axis 174. First and second side edges 170 and 172 (such as leading and trailing edges) may extend between the first and second upper surfaces 162 and 164 from the root 166 to the tip 168. A span axis 174 may be defined as extending between the root 166 and the tip 168, and may be disposed equidistant from the first and second sides 170, 172, for example.

A chordwise (chord wise)182 direction may be defined as extending between the first and second sides 170, 172, which is orthogonal to the spanwise axis 174 and anywhere along the blade 134. As shown, the root 166 is longer in the chordwise direction than the tip 168 such that the body 160 includes a decreasing width extending toward the tip 168 as measured in the chordwise direction. Alternatively, the blade 134 may have a constant chord along the length of the blade 134, or a varying chord, such as a constant rate of change for a chord extending between the root and tip. Furthermore, any variation in chord is contemplated to define the geometry of the blade, such as a constant, varying, stepped, unique or non-constant variation in the width of the blade measured in the chordwise direction. Alternatively, it is contemplated that the body 160 may comprise any blade shape, such as geometric, square, rectangular, triangular, circular, unique, deformable, converging, diverging, widening, thinning, or thickening, in non-limiting examples. While the root 166 and tip 168 are shown as flat linear portions, in a non-limiting example, either the root 166 or tip 168, or both, may be flat, linear, rounded, curved, arcuate, concave, convex, sinusoidal, stepped, saw-tooth, unique, deformable, or any combination thereof, such that an infinite number of shapes for the root 166 and tip 168 may be contemplated. Similarly, an infinite number of geometric shapes or shapes for the first and second side edges 170, 172 are contemplated, such as linear, flat, rounded, curved, arcuate, concave, convex, sinusoidal, stepped, saw tooth, unique, or deformable, or any combination thereof, in non-limiting examples. Where the shape of the first or second side 170, 172 is non-linear or non-uniform between the edges 170, 172, the span axis 174 may be non-linear. Thus, it should be understood that a variety of different blade shapes are contemplated. A blade iron base 176, which may be a washer, may be mounted on the body 160 on the first upper surface 162 and may be substantially similar to the blade iron base 76 depicted in FIG. 2, the blade iron base 176 including a set of mounting holes 180.

The body 160 may be divided into five sections, including the first three sections as a first section 190, a second section 192, and a third section 194, which may be substantially similar to, for example, the first, second, and third sections 90, 92, 94 of fig. 2.

The third section 194 may begin or end partway between the root 166 and the tip 168, or at 50% of the spanwise distance 150 relative to the span axis 174. In such an example, the first segment 190 or the second segment 192 may cover 50% of the blade in the span-wise direction. In a non-limiting example, the third section 194 may cover 5-15% of the blade 134, or a smaller installation such as 5%, 2%, or 1%, while it is contemplated that the third section 194 may cover a larger portion of the blade 134, such as 33%, 50%, or more. The second section 192 then covers the remaining area of the blade 134, such as the remaining area extending to the tip 168.

Alternatively, the transition section 194 may begin or end along the span axis 174 at one third of the blade 134, at the spanwise distance 152 of 33%, or at the spanwise distance 154 of 66% along the span axis 174. In such an example, the first or second sections 190 or 192 may cover 33% or 66% of the blade, while the other of the first or second sections 190 or 192 covers the remaining sections not occupied by the third section 194.

The blade 134 may optionally include a fourth section 196 and a fifth section 198. Fifth segment 198 may be disposed at root 166, and fourth segment 196 may be disposed between first segment 190 and fifth segment 198. The fourth section 196 may include a transition cross-section or profile similar to the third sections 94, 194 as described herein, and the fifth section 198 may include a cross-section including a planar upper surface 162 and a lower surface 164 similar to the second sections 92, 192 as described herein. Fourth section 196 may provide a transition between the lifting or airfoil profile of first section 190 and the flat profile of fifth section 198. In one non-limiting example, the fourth segment 196 may be arranged complementary to the blade iron base 176, with the span range of the fourth segment 196 beginning and ending with respect to the blade iron base 176. The fifth segment 198 may terminate at the root 166.

It should be appreciated that the blade 134 may be divided into three sections or five sections, while it is further contemplated that the blade 134 may include any number of sections, which may be arranged in a number of different ways. Preferably, the area occupied by the sections with aerodynamic lift or airfoil profiles is maximized to maximize aerodynamic benefits while balancing the sections with flat upper and lower surfaces to provide the desired consumer aesthetics and a simple bottom surface 164. Increasing the length of the transition section may provide some aerodynamic benefits while maintaining the traditional aesthetics of the fan. Thus, a balance may be struck between the size of the different sections and the aerodynamic or aesthetic requirements of a particular fan or implementation thereof.

Referring now to fig. 7-12, six different exemplary aerodynamic lift or airfoil sections or profiles are shown, with the understanding that the possibilities of airfoil profiles are not limited to only those airfoil profiles shown in the drawings, but other features providing aerodynamic or efficiency benefits may be combined or utilized therefor. Utilizing different aerodynamic lift or airfoil sections in combination with a tip having a flat upper surface and a flat lower surface may provide improved blade efficiency while providing the consumer with the aesthetic appearance of a traditional blade having a plain bottom surface.

Referring now to fig. 9, the airfoil section has a flat-bottomed airfoil profile 208. The flat bottom airfoil 208 may include an upper surface 212 and a flat lower surface 214 extending between a leading edge 216 and a trailing edge 218. The flat bottom airfoil 208 may be asymmetric about a vertical axis 210 equidistant from the leading edge 216 and the trailing edge 218. For example, the upper surface 212 may have an arcuate convex shape. The planar lower surface 214 is planar, similar to the planar lower surface of fig. 3-5. In one example, a blade having a flat-bottomed airfoil profile 208 may be arranged at an angle of attack. The enlarged upper surface 212 may provide increased downward force from the blade by increasing the total volumetric flow generated by the flat bottom airfoil 208 to increase blade efficiency.

Referring now to FIG. 10, a fan blade may have a cross-sectional profile that is a symmetrical airfoil 230 that includes an upper surface 232 and a lower surface 234 that extends between a leading edge 236 and a trailing edge 238 to define a linear chord line 240 extending between the leading edge 236 and the trailing edge 238. The symmetric airfoil 230 may be arranged at an angle of attack 242, for example, with the chord line 240 oriented off of the axis of rotation or horizontal axis to increase the aerodynamic performance of the symmetric airfoil 230. The symmetrical airfoil 230 positioned at the angle of attack 242 may increase the overall downward flow produced by the blade as well as other aerodynamic benefits.

Referring now to FIG. 11, the cross-sectional profile of the fan blade may include a semi-symmetrical airfoil 250. The semi-symmetric airfoil 250 may include an upper surface 252 and a lower surface 254 that extend in a chordwise direction between a leading edge 256 and a trailing edge 258 with a non-linear chord line between the leading edge 256 and the trailing edge 258. The upper surface 252 and the lower surface 254 may be non-uniformly rounded such that one surface 252 is longer than the other surface 254. The semi-symmetric airfoil 250 may be, for example, a balance between the flat bottom airfoil of fig. 9 and the symmetric airfoil of fig. 10, and may be arranged at an angle of attack to increase flow. The semi-symmetrical airfoil 250 may increase the overall downward flow produced by the blade as well as other aerodynamic benefits.

Referring now to FIG. 12, the fan blade may be contoured as a lower cambered airfoil profile 270 that includes an upper surface 272 and a lower surface 274 and extends between a leading edge 276 and a trailing edge 278. The upper surface 272 may be convex, while the lower surface 274 may be generally concave. The lower cambered airfoil 270 may be a leading airfoil having a concave surface of the lower surface 274 beginning near the leading edge 278. In a non-limiting example, the leading edge 256 and the trailing edge 258 may be rounded or radiused, while flat or other geometries are contemplated. The lower cambered airfoil 270 may be disposed at an angle of attack and may provide increased downward force generated by the blade to improve overall flow, thereby increasing blade efficiency.

Referring now to FIG. 13, another fan blade may be contoured as a lower cambered airfoil 290 that includes an upper surface 292 and a lower surface 294 and extends between a leading edge 296 and a trailing edge 298. In comparison to fig. 12, the lower cambered airfoil 290 of fig. 13 is a trailing airfoil providing a concave lower surface 294 that begins further from the leading edge 296 and includes an inflection point 300 closer to the center of the airfoil 290 between the leading edge 296 and the trailing edge 298. The lower cambered airfoil 290 may be disposed at an angle of attack and may provide increased downward force generated by the blade to improve overall flow, thereby increasing blade efficiency.

Referring now to FIG. 14, the aerodynamic profile for a fan blade may be another lower cambered airfoil 310 that includes a convex upper surface 312 and a concave lower surface 314, the aerodynamic profile having a leading edge 316 and a trailing edge 318 with a uniform thickness between the upper surface 312 and the lower surface 314. The lower cambered airfoil 310 may be arranged at an angle of attack and may provide increased downward force generated by the blade to improve overall flow, thereby increasing blade efficiency.

A lifting or airfoil section, portion or aerodynamic profile as described herein, such as the section or aerodynamic profile of fig. 2, 3 or 6, which illustrates that the first section 90, 190 may comprise any of the profiles shown in fig. 7-12, or any combination of elements thereof, or any other geometry suitable for improving ceiling fan operating efficiency due to the aerodynamic section or profile that reduces aerodynamic drag, turbulence, or increases boundary layer attachment along at least a portion of one or more surfaces relative to conventional profiles or blade shapes. Having the top end 68, 168 of the second section 92, 192 of fig. 2, 4 or 6 provides the consumer with a pleasing aesthetic appearance of a conventional fan blade and a pristine bottom surface while achieving the benefits of the first section 90, 190. Similarly, as shown in FIG. 8, utilizing fifth section 198 provides tip 168 and root 166 having flat upper and lower surfaces 162, 164, which provides a traditional consumer aesthetic with a plain bottom surface when viewing blade 134 along root 166 or tip 168, while achieving the aerodynamic benefits of first section 190.

Referring now to FIG. 15, the blade section 330 may include an upper surface 332 and a lower surface 334, each surface 332, 334 being flat and parallel to each other. The leading and trailing edges 336, 338 may be flat and arranged orthogonally to the upper and lower surfaces 332, 334. Alternatively, it is contemplated that the leading edge 336 and the trailing edge 338 may be rounded or beveled. Blade section 330 provides an aesthetic appearance to the ceiling fan that is desirable for consumers to use for viewing in conventional ceiling fans. For example, the blade cross-section 330 may be used in the second sections 92, 192, as described herein.

Referring now to FIG. 16, another exemplary blade 350 may include a blade section 352 having an upper surface 354 and a lower surface 356 that are parallel to each other. For example, the blade section 352 may be disposed at a tip of the blade 350. Additionally, the blade 350 may include an airfoil section 360, which is illustrated as an exemplary symmetric airfoil (partially shown in phantom). The airfoil section 360 also includes an upper surface 354 and a lower surface 356. The lower surface 356 at the airfoil section 360 is disposed at an angle of attack 362 relative to a horizontal axis 364 and relative to the lower surface 334 of the blade section 352. Thus, the airfoil section 360 may be disposed at an angle of attack 362 while the blade section 352 is not disposed at the angle of attack 362 to define a twist 366 of the blade 350. In one example, the twist 366 may be positioned at a transition section (such as the third section 94 of fig. 2). Accordingly, airfoil section 360 may provide improved aerodynamic performance at an angle of attack 362 while blade section 352 remains in a significantly flat position that is aesthetically pleasing to the consumer.

The blades and segments thereof as described herein provide increased overall flow to the ceiling fan, thereby increasing efficiency while maintaining the aesthetic appearance of having the consumer's desired pristine bottom surface of the ceiling fan. More specifically, the airfoil section provides an increased air downforce, which increases the overall volume of the airflow, while the flat upper and lower surfaces of the blade match the conventional fan blade style. In addition, the third section provides a smooth transition between the airfoil and blade sections that minimizes losses while providing an aesthetically appealing transition between the sections.

To the extent not described, different features and structures of the various features may be used in combination as desired. A feature that is not shown in all aspects of the disclosure is not meant to be construed as it cannot be done, but for brevity of description. Thus, various features of the different aspects described herein can be mixed and matched as desired to form new features or aspects thereof, whether or not such new aspects or features are explicitly described. The present disclosure encompasses all combinations or permutations of features described herein.

This written description uses examples to describe in detail the aspects described herein, including the best mode, and to enable any person skilled in the art to practice the aspects described herein, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the aspects described herein is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.