Ceiling fan blade

A ceiling fan or similar air-moving device can include a motor for rotating one or more blades to drive a volume of air about a space. The blade can include a body having an outer surface with a flat top surface and a flat bottom surface, and a side edge. The top surface includes a chamfered portion extending between a flat portion, and the side edge.

BACKGROUND

Ceiling fans are machines typically suspended from a structure for moving a volume of air about an area. The ceiling fan includes a motor, with a rotor and stator, suspended from and electrically coupled to the structure. A set of blades mount to the rotor such that the blades are rotatably driven by the rotor and can be provided at an angled orientation to move a volume of air about the area. As the cost of energy becomes increasingly important, there is a need to improve the efficiency at which the ceiling fans operate.

Chamfered edges have been provided on lower surfaces of ceiling fan blades for aesthetic reasons. But such structures have been found at best to have no effect on air flow and at worst to reduce the effectiveness of air flow generated by the blades.

BRIEF DESCRIPTION

In one aspect, the disclosure relates to a blade for a ceiling fan, the blade having a body with an upper surface including a chamfered portion, a lower surface, a root and a tip defining a span-wise direction therebetween. A leading edge and a trailing edge each spaces the upper surface and the lower surface and defines a chord-wise direction between the leading edge and the trailing edge. The chamfered portion extends along at least a portion of the leading edge, the trailing edge, or the tip.

DETAILED DESCRIPTION

The disclosure is related to a ceiling fan and ceiling fan blade, which can be used, for example, in residential and commercial applications. Such applications can be indoors, outdoors, or both. While this description is primarily directed toward a residential ceiling fan, it is also applicable to any environment utilizing fans or for cooling areas utilizing air movement.

Referring now toFIG. 1, a ceiling fan10is suspended from a structure12. In non-limiting examples, the ceiling fan10can include one or more ceiling fan components including a hanger bracket14, canopy16, a downrod18, a motor adapter20, a motor housing22at least partially encasing a motor24having a rotor26and a stator28, a light kit30, and a set of blade irons32. In additional non-limiting examples, the ceiling fan10can include one or more of a controller, a wireless receiver, a ball mount, a hanger ball, a light glass, a light cage, a spindle, a finial, a switch housing, blade forks, blade tips or blade caps, or other ceiling fan components. A set of blades34can extend radially from the ceiling fan10, and can be rotatable to drive a volume of fluid such as air. The blades34can be operably coupled to the motor24at the rotor26, such as via the blade irons32. The blades34can include a set of blades34, having any number of blades, including only one blade.

The structure12can be a ceiling, for example, from which the ceiling fan10is suspended. It should be understood that the structure12is schematically shown and is by way of example only, and can include any suitable building, structure, home, business, or other environment wherein moving air with a ceiling fan is suitable or desirable. The structure12can also include an electrical supply36and can electrically couple to the ceiling fan10to provide electrical power to the ceiling fan10and the motor24therein. It is also contemplated that the electrical supply be sourced from somewhere other than the structure12, such as a battery or generator in non-limiting examples.

A controller38can be electrically coupled to the electrical supply36to control operation of the ceiling fan10via the electrical supply36. Alternatively, the controller38can be wirelessly or communicatively coupled to the ceiling fan10, configured to control operation of the ceiling fan10remotely, without a dedicated connection. Non-limiting examples of controls for the ceiling fan10can include fan speed, fan direction, or light operation. Furthermore, a separate wireless controller40, alone or in addition to the wired controller38, can be communicatively coupled to a controller or a wireless receiver in the ceiling fan10to control operation of the ceiling fan10. It is further contemplated in one alternative example that the ceiling fan be operated by the wireless controller40alone, and is not operably coupled with the wired controller38.

Referring toFIG. 2, one blade34is isolated from the remainder of the fan10ofFIG. 1for illustration. Three fastener apertures50are provided in the blade34for fastening the blade to the motor24for rotating the blade34about the fan10, preferably via a blade iron32. Any number of fastener apertures or indeed any blade-attachment method or mechanism is within the scope of this disclosure. The blade34includes an outer surface52including a top surface54. The top surface54terminates at a side edge56. The top surface54can include a flat portion58and a top curved transition60transitioning from the flat portion58to the side edge56. Alternatively, the top surface need not be flat, but can include alternative geometries extending to the curved transition60. In one example, the curved transition60can be about one inch from the top surface58to the side edge56, while any width is contemplated. In another example, the curved transition60can extend between 5%-40% of the chord-wise width of the blade between the opposing side edges56, while distances less than 5% or greater than 40% are contemplated.

The blade34further includes a tip62and a root64, with the root64adjacent the fastener aperture50and the tip62opposite the root64. Curved corners66transition between the tip62and the side edges56, while it should be appreciated that the curved corners66can be optional or can include other shapes, such as sharp corners, for example. A chord-wise direction can be defined between the opposing side edges56and a span-wise direction can be defined between the tip62and the root64. The blade34can widen extending from the root to the tip in the span-wise direction, defined in the chord-wise direction, while any top-down shape for the blade is contemplated, such as having a thinning chord-wise width defined in the span-wise direction extending outwardly. Non-limiting examples of blade shapes can include squared, rectangular, curved, angled, or rounded.

Furthermore, the blade34can include a first edge68and a second edge70as the side edge56, which can be arranged as a leading edge and a trailing edge, respectively, while the particular arrangement can vary based upon a rotational direction of the blade. The chord-wise direction can thus be defined between the first edge68and the second edge70, defining a blade chord. As is appreciable, the blade chord as illustrated increases from the root64toward the tip62.

Further still, the curved transition60can extend along the entirety of the first edge68, the second edge70, the tip62, and/or the root64. As shown, the curved transition60extends along the first and second edges68,70and the tip62, curving at the corners66where the side edges68,70meet the tip62.

Referring toFIG. 3, taken across the section III-III ofFIG. 2, the blade34further includes a flat bottom surface80and a bottom curved transition82transitioning from the flat bottom surface80to the side edge56. The side edge56includes a width84to define a distance spacing the curved transition60at the top surface54from the curved transition82of the bottom surface80. In one additional example, the width84can be zero, such that the curved transition60from the top surface54transitions immediately to the curved transition82of the bottom surface80. The blade34can be symmetric about a centerline86, while it is contemplated that the blade34can be non-symmetric, can be curved, or can include other shapes and should not be limited to the symmetric shape as shown.

Furthermore, it should be appreciated that the blade34can be mounted at an angle of attack. The angle of attack can be defined based upon an angular position of the blade34, such that the flat bottom surface80and the flat top surface54are arranged at an angle relative to the horizontal, or to a surface from which the ceiling fan hangs or suspends above. The angle of attack permits the blade34to drive a volume of air, pushing the air in an upward or downward direction based upon the angle and the direction of movement of the blade34. Without the angle of attack, the air movement generated by the blade34would be minimal.

Referring now toFIG. 4, an enlarged section view of the first edge68of the blade34better shows the curvature of the curved transitions60,82. The curved transitions60,82can provide for transitioning between the top and bottom surface54,80, to the side edge56arranged perpendicular to the top and bottom surfaces54,80. One or both of the curved transitions60,82can be specifically shaped as having an elliptical arc, defining at least a portion of an elliptical profile for the curved transitions60,82. More specifically, one or more of the curved transitions can be represented by equation (1) written in standard form:

x2a2+y2b2=1(1)
where x represents an x-axis90and y represents a y-axis88in Cartesian coordinates. The x-axis90can be defined in the direction extending from the top surface54to the bottom surface80, and the y-axis88can be defined in the chord-wise direction. Furthermore, a represents a length for the ellipse respective of the x-axis, and b represents a length for the ellipse respective of the y-axis. It should also be appreciated that where a=b, the ellipse can be a circle, defining no major or minor axis, as the diameters for a circle are equal. Additionally, all other ellipses can be non-circular, where a does not equal b, defining major and minor axes as the greatest and least diameters, respectively. Thus, it is contemplated that the curved transitions60,82can define an elliptical shape, a non-circular elliptical shape, a parabolic shape, or a hyperbolic shape.

InFIG. 4, the curved transition60from the top surface54to the side edge56can be represented by equation (2) below, for example:

x262+y212=1(2)
where a=6 and b=1. Furthermore, the curved transition82from the side edge56to the bottom surface80can be 90-degrees of a circular ellipse, represented by equation (3) below, for example:

x222+y222=1(3)
where a=2 and b=2. It should be appreciated that while the curved transition82at the bottom surface80is shown as an ellipse having an equal major and minor axis forming a circle, it can alternatively be an ellipse having unequal major and minor axes. Furthermore, the specific equations representing the curved transitions60,82can be any suitable elliptical arc, and should not be limited by the specific arcs defined by equations (2) and (3) above.

In an example where one of the curved transitions60,82is parabolic, an equation representing at least a portion of the curvature of the curved transition60,82can be represented in standard form as:
(x−h)2=4p(y−k)  (4)
where the focus can be defined as (h, k+p) and the directrix is defined as y=k−p. x can represent the x-axis90and y can represent the y-axis88.

In another examples, where one of the curved transitions60,82is hyperbolic, an equation representing at least a portion of the curvature of the curved transition60,82can be represented in standard form as:

(x-h)2a2-(y-k)2b2=1⁢⁢or(5)(y-k)2a2-(x-h)2b2=1(6)
where equation (5) is based upon a horizontal transverse axis and equation (6) is based on a vertical transverse axis, which ultimately depends on the local coordinate system defining the curved transitions60,82of the blade34. (h, k) can be used to define a center for the hyperbola, while x can represent the x-axis90and y can represent the y-axis88.

The curved transition60at the top surface54can have a greater chord-wise extent from the side edge56than that of the curved transition82at the bottom surface80, as can be appreciable as illustrated by the broken lines88,90inFIG. 4. Such a greater chord-wise extent can be defined by a greater major axis for the elliptical curvature of the curved transition60at the top surface54, for example. Furthermore, it should be appreciated that while shown as having both curved transitions60,82, it is contemplated that the blade34only includes one curved transition60, with a corner or edge replacing the second curved transition82, for example, such as along the broken lines at either curved transition60,82.

It should be appreciated that one or more curved transitions60,82between the top surface54and the bottom surfaces80, and the side edge56can provide for increased efficiency for the blade34. As both the first edge68and the second edge70can include the curved transitions60,82, such an efficiency gain can be appreciated in either rotational direction of the blade34. Furthermore, the elliptical geometry for the one or more curved transitions60,82can provide for improved efficiency for the blades34, as compared to a blade without a curved transition.

It should be further appreciated that additional geometries for the curved transition60are contemplated, such as that of a root function or a logarithmic function. For example, the curved transition60can be represented as a nth root function as:

f⁡(x)=xn(7)
or
y=x1/n(8)
where x represents a value for the x-axis, and f(x) and y represent a value for the y-axis, and n represents any real number. As such, the nth root function can be a square root function, or a cubic root function, or any variation thereof. Additionally, the curved transition60can be represented as a logarithmic equation as:
y=logb(x)  (9)
where b is the logarithmic base, x represents the value for the x-axis, and y represents the value for the y-axis.

Further still, it should be understood that a combination of different curved transitions60can be used for a single blade. For example, a first curved transition60can be used for a leading edge and a different curved transition can be used for a trailing edge. In another example, a first curved transition60can be used for the curved transition at the top surface54, and a different second curved transition82can be used at the bottom surface80. In yet another example, the curved transition60can vary along the leading edge, trailing edge, upper surface, lower surface, or otherwise in the span-wise direction between the root and the tip. Therefore, it should be appreciated that a myriad of different curved transitions can be utilized with a fan blade, which can provide for further increasing efficiency, as well as being utilized in either rotational direction.

Referring now toFIGS. 5A and 5B, another blade110is shown in cross-sectional profile and top view, respectively. The blade110can include a root108and a tip106, and can have a top-down shape substantially similar to that as shown in the top-down view ofFIG. 2, for example, while other variations in top-down shape are contemplated. The blade110can include a leading edge112and a trailing edge114, along with a top surface116and a bottom surface118. Each of the leading edge112and the trailing edge114can include a radiused or rounded transition120between the top surface116and the bottom surface118.

The blade110can include at least one chamfered edge122transitioning between the top surface116and one of the leading edge112or the trailing edge114. As shown, the chamfered edge122is provided at both the leading edge112and the trailing edge114. In one example, the chamfered edge122can extend around the blade110continuously along the leading edge112, the tip, and the trailing edge114, while it is contemplated that any of, or one or more portions of the root, the tip, the leading edge112, and the trailing edge114includes the chamfered edge122. The chamfered edge122can meet the leading edge112and the trailing edge114at the rounded transition120. Similarly, a radiused or rounded transition124can be provided at the junction between the top surface116and the chamfered edge122.

In one example, the chamfered edge122can be between 5% and 40% of the chord-wise width of the blade, measured extending between the leading edge112and the trailing edge114. The chamfered edge122can be arranged at an angle130relative to the top surface116less than 180-degrees, but greater than 90-degrees. In one example, the angle130can be between 175-degrees and 155-degrees. Additionally, the chamfered edge122can be arranged at an angle132relative to the leading edge112or the trailing edge114. The angle132can be greater than 90-degrees. In one example, the angle can be between 95-degrees and 115-degrees. In one additional alternative example, the chamfered edge122can be radiused, such as concave or convex.

Additionally, the height of chamfered edge122can be such that the thickness of the leading edge112or the trailing edge114meets regulatory requirements. As such, the thickness between the top surface116and the bottom surface118will necessarily be thicker than that of the leading edge112or the trailing edge114having the chamfered edge122. Furthermore, the rounded transitions120can be the minimum regulatory required rounded edge meeting the leading edge112or the trailing edge114. In one example, the leading edge112or the trailing edge114can be flat, perpendicular to the top surface116and the bottom surface118, with the rounded transitions connecting the leading and trailing edges112,114to the top and bottom surfaces116,118. Alternatively, it is contemplated that the leading and trailing edge112,114are wholly radiused.

The blade110including the chamfered edge122provides for improved blade efficiency and aerodynamic performance. Such as blade110can require lesser energy per unit volume of air moved, thereby improving overall efficiency of the fan. Furthermore, the flat bottom surface provides for a traditional aesthetic for the fan blade that consumers find appealing. Thus, efficiency can be improved without sacrificing visual appeal of the ceiling fan or blades themselves.

The blades and sections thereof as described herein provide for both increased total flow volume for a ceiling fan, resulting in increased efficiency, while maintaining the aesthetic appearance having an unadorned bottom surface of a ceiling fan that consumers desire. More specifically, the curved transitions60,82provide for increased downward force on air which increases the total volume of airflow, while the flat upper and lower surfaces of the blade match traditional fan blade styles, providing a pleasing or appealing user aesthetic.

To the extent not already described, the different features and structures of the various features can be used in combination as desired. That one feature is not illustrated in all of the aspects of the disclosure is not meant to be construed that it cannot be, but is done for brevity of description. Thus, the 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 the new aspects or features are expressly described. All combinations or permutations of features described herein are covered by this disclosure.