Blade structure and ceiling fan having the same

A blade structure and ceiling fan having the same are disclosed. The blade structure includes a blade root, a blade tip, and a first vertex and a second vertex between the blade root and the blade tip. The blade bends from blade root to the first vertex, the blade tip and then bends from the blade tip to the second vertex and back to the blade root to form a hollow structure. The ceiling fan with the blade structure not only provides air modulating function but also has unique modeling.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of Taiwan Patent Application No. 100138252, filed on Oct. 21, 2011, in the Taiwan Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a ceiling fan and its blade structure, and more particularly to a blade structure and a ceiling fan having the same that have a hollow structure with different bending radians to simultaneously satisfy airstream control and unique appearance.

2. Description of the Related Art

In modern living, ceiling fans have become popular auxiliary devices for producing airflow in business and household buildings due to the feature of large air blowing area that effectively controls airflow and temperature.

In the structures of the ceiling fans and the blades, however, are necessary components. If the structure of the blades is not well designed, the rotational speed and airflow of the ceiling fan may be affected, noise may be generated during the rotation process, and the stability of the operation of the ceiling fan may be influenced owing to the undue air resistance caused by the blades. The ceiling fans in the buildings, in addition to providing major ventilation functions, should also provide stylist accent per consumers' demand. Therefore, a beautiful design with low air resistance, high rotational speed, and low noise has become an important subject matter in ceiling fan development and application, and is the major difficult task that needs to be overcome by ceiling fan manufacturers.

The ceiling fan blade of Taiwan design patent number D139690, for example, does not take into account the air resistance, appropriate airflow, stability and reasonable noise threshold value; thus not applicable to merchantable products. The present invention provides a reasonable and practicable scheme contemplating shape, airflow, stability, noise values and other various empirical desires.

SUMMARY OF THE INVENTION

In view of the shortcomings of the prior art, the inventor(s) of the present invention based on years of experience in the related industry to conduct extensive researches and experiments, and finally developed a blade structure and a ceiling fan having the blade structure as a principle objective to simultaneously provide blades having different bending radians and a hollow structure at a horizontal direction and a vertical direction. It does not only achieve features of low wind resistance, high rotational speed, low noise but also has beauty and modeling to greatly improve the overall performance and visual sense.

The invention provides a blade structure comprising a blade root at one end, a blade tip located at the other end, and a first vertex and a second vertex located between the blade root and the blade tip, wherein the blade is bent from the blade root to the first vertex, and further to the blade tip, and the blade is bent from the blade tip to the second vertex, and further to the blade root so as to form a hollow structure. At a first side of a first axis, a first node and a second node are located between the blade root and the first vertex. A maximum slope of the blade to a first axis occurs at the first node, and a maximum horizontal included angle between the blade and a second axis which is perpendicular to the first axis occurs at the second node. A ceiling fan capable of containing air regulation and beauty modeling can be achieved through the foregoing blade structures.

The invention further provides a ceiling fan having a main body, a plurality of blades and a main body lower case. The main body is for providing a rotation power. The plurality of blades is mounted to the main body through the main body lower case. The ceiling fan is characterized in that a blade of the plurality of blades comprising the blade root at one end, a blade tip located at the other end, and a first vertex and a second vertex located between the blade root and the blade tip, wherein the blade is bent from the blade root to the first vertex, and further to the blade tip, and the blade is bent from the blade tip to the second vertex, and further to the blade root so as to form a hollow structure. At a first side of a first axis, a first node and a second node are located between the blade root and the first vertex, wherein a maximum slope of the blade to the first axis occurs at the first node and a maximum horizontal included angle between the blade and a second axis which is perpendicular to the first axis occurs at the second node.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The foregoing and other technical characteristics of the present invention will become apparent with the detailed description of the preferred embodiments and the illustration of the related drawings.

With reference toFIG. 1for a schematic diagram of a blade structure according to an embodiment of the invention is depicted.FIG. 2is a top view of a blade structure according to an embodiment of the invention. As shown inFIG. 1andFIG. 2, the invention provides a blade structure comprising a blade root22at one end, a blade tip24located at the other end, and a first vertex S1and a second vertex S2located between the blade root22and the blade tip24. The blade20is bent from the blade root22to the first vertex51, then to the blade tip24, and bent further from the blade tip24to the second vertex S2, then back to the blade root22to form a hollow structure Ho. The material of the blade20of the invention can, but not limited to, be polycarbonate (PC), plastic bent wood, metal panel, acrylonitrile butadiene styrene (ABS) or acrylonitrile styrene (AS).

The blade20has a first side edge SD1and a second side edge SD2. The first vertex S1and the second vertex S2are located at the first side edge SD1of the blade20and are respectively located at a first side (as shown in an arrow X1) and a second side (as shown in an arrow X2) of a first axis X horizontally extended from the blade root22. Distance D1between the first vertex S1and the first axis X is the maximum distance between the first axis X and the first side edge SD1in the first side X1of the first axis X. Distance D2between the second vertex S2and the first axis X is the maximum distance between the first axis X and the first side edge SD1in the second side X2of the first axis X.

With reference toFIG. 1toFIG. 3,FIG. 3is a cross-sectional drawing of a blade structure taken along a section (LN2-LN2′) ofFIG. 1. As shown inFIG. 1toFIG. 3, three coordinate axes of X, Y, and Z at a three-dimensional space are firstly defined as follows: X coordinate axis is the first axis X depicted in the invention, and Z coordinate axis is a second axis Z depicted in the invention, and Y coordinate axis is a third axis Y depicted in the invention. The first axis X, the second axis Z and the third axis Y are perpendicular to each other, wherein the hollow structure Ho of the blade is hollow along the third axis Y as shown in the figure.

In an embodiment, a first node N1, a second node N2and a third node N3are located between the first vertex S1and the blade root22on the first side edge SD1of the blade20at the first side X1of the first axis X. The first node N1, the second node N2and the third node N3are further defined as the following. In an embodiment, the maximum slope of the blade20with respect to the first axis X occurs on a tangent L1of blade20at the first node N1. The second node N2is located between the first vertex S1and the first node N1. The second node N2of the blade20has the maximum horizontal included angle θ between the blade20and the second axis Z, wherein the horizontal included angle θ in the preferred embodiment is about 18 to 25 degrees. The third node N3is located at a location of the blade root22where the horizontal included angle between the blade root22and the first axis X is zero. The second vertex S2and the first vertex S1of the blade20are located at the same section of the third axis Y. In addition, the blade tip24on the first side edge SD1of the blade20further includes a fourth node N4. The fourth node N4is located at a section (LN4-LN4′) of the blade tip24that is perpendicular to the first axis X.

Besides the foregoing nodes N1-N4, the second side edge SD2of the blade20has a fifth node N5located on a section (LN2-LN2′) taken along the third axis Y, in which the second node N2is located. The blade20has a center point M taken along the second axis Z. Between the section of the fifth node N5taken along the third axis Y and the section of the center point M taken along the third axis Y is the maximum distance D3between the second side edge SD2of the blade20and center point M in the first side X1of the first axis X. In a preferred embodiment, the maximum horizontal included angle θ of blade20is an included angle between the second axis Z and the line taken along the second node N2to the fifth node N5. The blade20of the blade structure according to the invention has a first surface SF between the first side edge SD1and the second side edge SD2. The first surface SF has a maximum width at the blade tip24, and the first surface SF of the blade20has a minimum width between the first node N1and the third node N3on the first side edge SD1.

In an embodiment, a first node N1, a second node N2and a third node N3are located between the first vertex S1and the blade root22on the first side edge SD1of the blade20at the first side X1of the first axis X. The first node N1, the second node N2and the third node N3are further defined as the following. In an embodiment, the maximum slope of tangent of the blade20with respect to the first axis X occurs on a tangent L1of blade20at the first node N1. The second node N2is located between the first vertex S1and the first node N1. The second node N2of the blade20has the maximum horizontal included angle θ between the blade20and the second axis Z is formed by a line extending from the second node N2of the blade20on the section (LN2-LN2′) and the second axis Z, wherein the horizontal included angle θ in the preferred embodiment is about 18 to 25 degrees. The third node N3is located at a location of the blade root22where the horizontal included angle between the blade root22and the first axis X is zero. The second vertex S2and the first vertex S1of the blade20are located at the same section of the third axis Y. In addition, the blade tip24on the first side edge SD1of the blade20further includes a fourth node N4. The fourth node N4is located at a section (LN4-LN4′) of the blade tip24that is perpendicular to the first axis X.

Besides the foregoing nodes N1-N4, the second side edge SD2of the blade20has a fifth node N5located on a section (LN2-LN2′) taken along the third axis Y, in which the second node N2is located. The blade20has a center point M taken along the second axis Z, and the center point M is located at a crosspoint between the section (LN1-LN2′) and the first axis X. Between the section of the fifth node N5taken along the third axis Y and the section of the center point M taken along the third axis Y is the maximum distance D3between the second side edge SD2of the blade20and center point M in the first side X1of the first axis X. In a preferred embodiment, the maximum horizontal included angle θ of blade20is an included angle between the second axis Z and the line taken along the second node N2to the fifth node N5. The blade20of the blade structure according to the invention has a first surface SF between the first side edge SD1and the second side edge SD2. The first surface SF has a maximum width at the blade tip24, and the first. surface SF of the blade20has a minimum width between the first node N1and the third node N3on the first side edge SD1.

With reference to Table I, the table I illustrates the airflow, rotation speed and noise with respect to various horizontal included angle θ on the second node N2. As shown in Table I, under a condition of using the same output power, take the section (LN2-LN2′) along the third axis Y as a basis where the second node N2and the fifth node N5are set thereon, while keeping other geometric relationship unchanged, and vary the horizontal included angle θ between the second axis Z and the line taken along the second node N2to the fifth node N5. The table illustrates the measurement of airflow, rotational speeds, and noise of the blade20with respect to various horizontal included angle θ.

With experimental observation and verification, when the horizontal included angle θ is smaller than 18 degrees, the airflow is dramatically reduced. When the horizontal included angle θ is greater than 25 degrees, the rotational speed and airflow are decreased, and the vertical vibration range of the blade20is increased to the extent that may affect the stability of the operation of the ceiling fan. A preferred embodiment is that the horizontal included angle θ between the second axis Z and the line taken along the second node N2to the fifth node N5is within a range of 18 to 25 degrees.

With reference toFIG. 4AandFIG. 4B,FIG. 4Ais a cross-sectional drawing of a blade structure taken along the section (J-J′) shown inFIG. 2.FIG. 4Bis a local enlarged diagram of a circle C shown inFIG. 4A. In an embodiment, the blade root22has a first connection member221and a second connection member223. The first connection member221is connected to the second connection member223through a tenon225. In the embodiment shown inFIG. 4AandFIG. 4B, the tenon225is disposed on the first connection member221and can be disposed at the second connection member223in other embodiments. As long as the embodiments that allow different kinds of tenons to closely connect the first connection member221and the second connection member223can become the embodiment for the tenon225depicted in the blade structure of the invention. In addition, the first connection member221and the second connection member223that are distant from the blade tip24can be closely connected together (as shown in the circle C1ofFIG. 4A).

With reference toFIG. 2,FIG. 4A,FIG. 4BandFIG. 5,FIG. 5is a schematic diagram of fastening portions of a blade structure shown inFIG. 2. As shown inFIG. 2,FIG. 4A,FIG. 4BandFIG. 5, the first connection member221and the second connection member223of the blade root22have the first fastening portion227and the second fastening portion229. The first connection member221and the second connection member223of the blade20are fastened on a main body lower case30of a ceiling fan (not shown in the figure) by using a screw301passing through the first fastening portion227. The second fastening portion229affixes the blade20to the main body lower case30by using a bolt302. With the foregoing fastening manners, the blade20can be fastened on the ceiling fan (not shown in the figure) via the main body lower case30.

In an embodiment, the first connection member221and the second connection member223of the blade root22can be connected via the tenon225. Afterward, the second fastening portion229affixes the blade20to the main body lower case30. Further, the first connection member221and the second connection member223of the blade20are fastened on the main body lower case30by using a screw301via the first fastening portion227. Since the blades are a composite layer structure, the error on the installation may easily influence the stability of the operation of the ceiling fan. Therefore, the fastening procedure in accordance with the mentioned steps not only achieves easy assembly but also enhances the stability of the blade when the ceiling fan operates.

With reference toFIG. 6,FIG. 7AandFIG. 7B,FIG. 6is a bottom view of a ceiling fan having blade structures according to an embodiment of the invention.FIG. 7Ais a cross-sectional drawing taken along a section (G-G′) shown inFIG. 6.FIG. 7Bis a local enlarged diagram of a circle H shown inFIG. 7A. In the embodiment shown inFIG. 6, the ceiling fan50has four blades20. The four blades20are fastened on a main body52of the ceiling fan50via the main body lower case30, the screw301and the bolt302, wherein the structure of the blade20is depicted in the foregoing embodiments, and there is no need to describe herein. The main body52of the ceiling fan50is utilized for providing a rotating power. The blade20is driven by the rotating power to perform rotation to achieve the effect of modulating airstream. At least one gasket303is disposed between the blades20. Further, at least one gasket303is also disposed between the first connection member221and the second connection member223in the blade20. The gasket303can be used for preventing noise or wear caused by the friction between the first connection member221and the second connection member223or the friction between the blade20.

The blade structure of the invention is to produce a specific hollow structure having various bending radians both at the horizontal direction and the vertical direction between the blade root and the blade tip. With calculations and experiments, the location and angle of the nodes on the blade may have the optimum standard. In addition, soft gaskets are respectively disposed between the blades and between connection members of the blade to reduce noise or abrasion caused by the friction between different connection members of the blade or different blades, wherein the friction was caused by the dynamic deformation of the blades. Not only does the blade structure of the invention increase the airflow of the ceiling fan, reduces noise, and improves the stability, but also provide the added value of unique and stylist appearance.

The invention improves over the prior art and complies with patent application requirements, and thus is duly filed for patent application. While the invention has been described by device of specific embodiments, numerous modifications and variations could be made thereto by those generally skilled in the art without departing from the scope and spirit of the invention set forth in the claims.