Fan blade of ceiling fan

Abstract

The invention relates to a fan blade (100) of a ceiling fan, comprising: a root (110) for mounting the fan blade (100) on a motor unit (200); and a body (120) extending from the root (110); wherein the body (120) is formed thereon with an elongated groove (130) extending along a trailing edge (142) of the body (120).

Description

Technical Field

[0001] The present invention relates to a fan blade of a ceiling fan, and more particularly, the fan blade has a structure with improved strength and stress distribution. Background Art

[0002] The fan blades of a ceiling fan are subjected to cyclic stresses during the operation of the fan due to the rotation and weight of the fan blades, which can lead to fan blade failure, which will injure nearby individuals and damage nearby objects. Therefore, regular inspections are required to monitor the condition of the fan blades for the purpose of detecting possible cracks and thus preventing sudden breakage. If there are minor nicks or cracks in the blades, they can be repaired with a good adhesive. However, if the cracks are severe or the blades are damaged, new blade replacements that match the size and design of the fan will be required.

[0003] In order to achieve different purposes, various fan blades have been introduced. For example, US9995313B2 discloses a fan blade intended to increase the air volume, which can be manufactured in a cost-effective manner. This ceiling fan has a blade body extending in a radial direction and including a first slit opening in a rotational direction at a rear edge of the blade body. In a circumferential cross-section including a front end portion of the first slit of the blade body in the rotational direction, the lower end portion of the front edge of the blade body in the rotational direction is positioned further above the lower end portion of the front end portion of the first slit in the up-down direction, and the lower end portion of the opening end portion of the radially outer edge of the first slit is positioned axially downward from the lower end portion of the front end portion of the first slit, and is positioned axially upward from the lower end portion of the opening end portion of the radially inner edge of the first slit. However, US9995313B2 does not aim to solve the problem of fan blade fatigue.

[0004] USRE48538E1 discloses a ceiling fan having a reinforcement for strengthening the fan blades, and also discloses a blade-falling prevention portion for locking the blades in a proper position, such as Figure 1 As shown. The blade is integrally formed by a root portion, a blade portion, and a step portion for maintaining the blade in a state of being inclined from a horizontal axis. The blade includes a curved portion located on the upstream side, a first reinforcement located on the upstream downstream side, and a plurality of second reinforcements located between the curved portion and the first reinforcement. The length of the first reinforcement is longer than the second reinforcement. Although the reinforcement helps to strengthen a specific portion of the fan blade where the reinforcement is formed, other portions without the reinforcement are still susceptible to rupture. In particular, the stress concentration at the mounting point of the fan blade on the motor is high.

[0005] The present invention is an improvement on USRE48538E1, which solves the problem of stress concentration at the installation point of the fan blade on the motor by providing a solution for strengthening the fan blade and improving the stress distribution of the entire blade. Summary of the invention

[0006] The main object of the present invention is to provide a fan blade for a ceiling fan with improved stress distribution. In particular, the present invention aims to solve the problem of high stress concentrations at the mounting points of fan blades on the motor, because they are prone to fracture. A solution is provided to migrate the stress from the mounting points to a suitable portion of the blade that has a higher stress-bearing capacity. Another object of the present invention is to provide a fan blade with a suitable portion for stress migration. Further, the present invention provides a fan blade with high structural integrity to withstand stress, especially stress migrated from the mounting points. In addition, the present invention provides features on the fan blade to maintain the core strength of the reinforcing ribs on the blade and the performance of the fan blade in terms of airflow, air delivery and speed. At the same time, the present invention aims to provide a fan blade that is different from existing fan blades, especially Figure 1 The fan blade shown is a compact fan blade having a smaller width.

[0007] The present invention satisfies at least one of the aforementioned purposes in whole or in part, wherein the present invention provides a fan blade for a ceiling fan, comprising a root for mounting the fan blade to a motor unit, and a body extending from the root; wherein the body has an elongated groove formed thereon extending along a rear edge of the body.

[0008] In one embodiment of the present invention, the elongated groove includes an inclined portion inclined from a portion of the body adjacent to the root portion, and a flat portion extending from the inclined portion toward a free end of the body.

[0009] According to a preferred embodiment of the present invention, the inclined portion has an inclined surface which is inclined from a higher surface of the body toward a lower surface of the body, which defines the flat portion.

[0010] Preferably, the root portion and the body have a plurality of elongated reinforcing ribs formed thereon.

[0011] Based on a preferred embodiment, the predetermined distance L between the tip of the reinforcing rib 122 closest to the trailing edge 142 and the farthest point of the inclined portion 131 from the proximal end 144 of the body 120 is 25 to 40 mm.

[0012] Preferably, the free end portion at the rear edge where the flat portion is located has a curved angle, and the curved angle is greater than the corner at the free end portion where the front edge of the body is located.

[0013] In a preferred embodiment, the fan blade further includes a step portion connecting the root and the body, wherein the step portion is inclined from the root at a higher surface to the body at a lower surface.

[0014] The root portion is preferably formed with a hole defining a mounting point for fastening a fastener therein to mount the fan blade to the motor unit.

[0015] Another aspect of the present invention provides a ceiling fan comprising: a motor unit; and a plurality of fan blades radially mounted on the motor unit, each fan blade comprising a root for mounting the fan blade to the motor unit; and a body extending from the root; wherein the body has an elongated groove formed thereon extending along a trailing edge of the body.

[0016] Preferably, the elongated groove includes an inclined portion which is inclined from a portion of the body adjacent to the root, and a flat portion which extends from the inclined portion toward a free end of the body. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present invention will now be described in more detail with reference to the accompanying drawings.

[0018] Figure 1 It is a fan blade of the prior art.

[0019] Figure 2 is a perspective view of a plurality of fan blades in a preferred embodiment.

[0020] Figure 3 is a perspective view of a fan blade in a preferred embodiment.

[0021] Figure 4 is generated by computer-aided engineering (CAE) Figure 1 A comparison of a prior art fan blade and a fan blade of the present invention is shown to illustrate the difference in stress distribution. FIG4(a) is a CAE of a prior art fan blade, while FIG4(b) is a CAE of the present invention. DETAILED DESCRIPTION

[0022] In order to better understand the present invention, preferred embodiments of the present invention illustrated in the accompanying drawings will be described in detail.

[0023] Disclosed herein is a fan blade 100 for a ceiling fan 10 having improved strength and stress distribution. In particular, the fan blade 100 disclosed herein solves Figure 1The prior art motor unit shown has a high stress concentration problem at the mounting points 111a of the fan blades 100a. The mounting points 111, 111a are points where fasteners are applied to attach the fan blades 100, 100a to the motor unit 200, so that the fan blades 100, 100a rotate as the motor unit 200 rotates. Due to the high concentration of stress at the mounting points 100a, cracks are likely to occur at these locations, causing the fan blades 100a to fall off the motor unit 200, which not only affects the performance of the ceiling fan 10, but also causes damage to objects near the ceiling fan 10 and injuries to people.

[0024] Reference Figure 2 , the ceiling fan 10 is attached to the ceiling through a coupling assembly 300, whereby a tube 400 of the ceiling fan 10 is suspended from the ceiling and connected to the motor unit 200. A plurality of fan blades 100 are radially mounted to the motor unit 200 so that the fan blades 100 and the motor unit 200 can rotate together during operation of the fan 10. Figure 3 In the preferred embodiment of the present invention shown, each fan blade 10 includes a root 110 and a body 120 extending from the root 110. The edge of the fan blade 100 that faces forward when the fan rotates is the leading edge 141 of the blade 100. During operation of the fan 10, the leading edge 141 moves through the air first, creating airflow and a cooling effect. The edge of the fan blade 100 that follows behind as the fan blade 100 moves through the air is the trailing edge 142.

[0025] like Figure 2 As illustrated, the root 110 is the portion of the fan blade 100 that is mounted to the motor unit 200. A partial or complete root 110 is located on the motor unit 200. In order to secure the root 110 to the motor unit 200, a fastening system is required. One or more holes defining a mounting point 111 of the fan blade 100 are formed on the root 110, preferably two holes 111, each of which is formed on two opposite sides of the proximal end of the root 110. Openings corresponding to the holes 111 of the fan blade 100 are also formed on the motor unit 211 for fasteners to be fastened into the holes of the fan blade 100, and then fastened into the openings of the motor unit 200 to mount the fan blade 100 on the motor unit 200.

[0026] refer to Figure 3, the body 120 is blade-shaped, having an elongated and wide structure. The body 120 has a free end 145, which is the distal end of the fan blade 100. There is a step portion 121 connecting the root 110 and the body 120, wherein the step portion 121 is inclined from the root 110 at a higher surface to the body 120 at a lower surface. It should be noted that the width of the body 120 is greater than the root 110 and the step portion 121. The step portion 121 is roughly an isosceles triangle, which bends inward from the trailing edge 142 toward the leading edge 141, so that the vertex of the isosceles triangle is adjacent to the leading edge 141. Preferably, the step portion 121 does not reach the leading edge 141. In this way, the body 120 is slightly inclined horizontally to achieve better air flow, reduce air resistance, and enhance the stability of the fan blade 100.

[0027] A plurality of reinforcing ribs 122 are formed on the root 110 and the body 120. In a preferred embodiment, there is a long reinforcing rib 122a adjacent to the leading edge 141, which extends from the root 110 and extends substantially along the body 120 toward the free end 145 of the body 120, for maintaining the balance of the fan blade 100. The remaining reinforcing ribs 122b are much shorter than the long reinforcing rib 122a, and extend only through the root 110, the step portion 121, and a small area of ​​the body 120 near the step portion 121. The lengths of the remaining reinforcing ribs 122b are gradually shortened, and therefore, the length of the reinforcing rib 122 closest to the trailing edge 142 is the shortest. This configuration of the reinforcing ribs 122 strengthens the fan blade 100 and distributes the stress near the leading edge 141 to the entire fan blade 100. Since the width of the body 120 is greater than the root 110 and the step portion 121, there is a horizontally extending portion of the body 120 where the reinforcing rib 122 is not formed. Preferably, the maximum width of fan blade 100 is 125 mm, more preferably about 120 mm.

[0028] The elongated groove 130 is formed on a horizontally extending portion of the body 120, the elongated groove 130 extends along the body 120 near the rear edge 142, and is slightly bent downward. The elongated groove 130 includes an inclined portion 131 and a flat portion 132. The inclined portion 131 is inclined from a portion of the body 120 near the root 110. More specifically, the inclined portion 131 is inclined at a position near the proximal end 144 of the body 120, but the position is significantly away from the proximal end 144 of the body 120. The inclined portion 131 has an inclined surface inclined from the higher surface of the body 120 toward the lower surface of the body 120, which defines a flat portion 132 extending from the inclined portion 131 toward the free end 145 of the body 120. The inclined portion 131 provides a sunken portion of the elongated groove 130, wherein the depth of the elongated groove 130 gradually decreases toward the free end 145.

[0029] according to Figure 3 , the tip of the last reinforcing rib 122 closest to the trailing edge 142 is represented as point "X", and the farthest point of the inclined portion 131 from the proximal end 144 of the body 120 is represented as point "Y". The predetermined distance between point "X" and point "Y" is represented as "L", and the predetermined distance "L" at least substantially maintains the core strength of the reinforcing rib 122 and the performance of the fan blade 100. If "L" is too short, the core strength of the reinforcing rib 122 will be affected. However, if "L" is too long, the airflow, air delivery and speed of the fan blade 120 will be affected. Therefore, it is preferred that "L" is preferably between 25 and 40 mm. In addition, the free end 145 of the body 120 at its trailing edge 142 where the flat portion 132 is located has a bend 143, and the angle of the bend is greater than the corner at the free end 145 where the leading edge 141 of the body 120 is located.

[0030] Another aspect of the present invention is to provide a ceiling fan 10, whose fan blades 120 each have an elongated groove 130 as described above. The ceiling fan 10 includes a motor unit 200 and a plurality of fan blades 100 radially mounted on the motor unit 200. Each fan blade 100 includes: a root 110 for mounting the fan blade 100 on the motor unit 200; and a body 120 extending from the root 110. Other features of the fan blade 100 are as disclosed above.

[0031] Figure 4(a) and Figure 4(b) show the computer-aided engineering (CAE) generated Figure 1A comparison diagram of a prior art fan blade 100a and a fan blade 100 of the present invention is depicted in order to show the difference in their stress distribution. Since the stress is highly concentrated at the mounting point 111a of the fan blade 100a, where the fasteners are applied to mount the fan blade 100a to the motor unit 200, the fan blade 100a of the prior art is prone to fracture at the mounting point 111a. The present invention solves this problem by having an elongated groove 130, thereby reducing the stress at the mounting point 111 by transferring some of the stress from the mounting point 111 to the elongated groove 130. This stress migration allows the stress to be less concentrated at the mounting point 111, but to be more evenly distributed throughout the fan blade 100, especially along the elongated groove 130. Compared to the same area of ​​the prior art fan blade 100a, the area "A" on the fan blade 100 of the present invention shows that more stress is migrated from the mounting point 111 to this area. In addition, the stress in the area "B" around the mounting point 111 on the fan blade 100 of the present invention is significantly reduced compared to the area "B" of the prior art fan blade 100a. According to FIG. 4(a), the stress experienced by the area "B" around the mounting point 111a of the prior art fan blade 100a is 271.6 MPa, while in FIG. 4(b) of the present invention, the stress experienced by the area "B" around the mounting point 111 is 228.9 MPa. The structure of the elongated groove 130 improves air cutting for generating better airflow velocity and conveying effect.

[0032] Although the above description contains many specifics, it is to be understood that the preferred forms of embodiment should not be considered as departing from the invention and that they may be modified within the scope of the appended claims.

Claims

1. A fan blade (100) of a ceiling fan, comprising: a root portion (110) for mounting the fan blade (100) on a motor unit (200); as well as a body (120) extending from the root (110); The body (120) is formed with an elongated groove (130) extending along a rear edge (142) of the body (120).

2. The fan blade (100) of claim 1, wherein the elongated groove (130) comprises: an inclined portion (131) inclined from a portion of the body (120) adjacent to the root portion (110); as well as A flat portion (132) extends from the inclined portion (131) toward a free end (145) of the body (120).

3. The fan blade (100) according to claim 2, wherein the inclined portion (131) has an inclined surface, which is inclined from a higher surface of the body (120) to a lower surface of the body (120), and the lower surface defines the flat portion (132).

4. The fan blade (100) according to claim 2 or 3, wherein the root portion (110) and the body (120) have a plurality of elongated reinforcing ribs (122) formed thereon.

5. The fan blade (100) according to claim 4, wherein a predetermined distance (L) between a tip of the reinforcing rib (122) closest to the trailing edge (142) and a farthest point of the inclined portion (131) from a proximal end (144) of the body (120) is 25 mm to 40 mm.

6. A fan blade (100) according to any one of the preceding claims, wherein the free end at the trailing edge (142) where the flat portion (132) is located has a bend angle (143), and the bending angle of the bend angle (143) is greater than the corner at the free end where the leading edge (141) of the body (120) is located.

7. The fan blade (100) according to any one of the preceding claims, further comprising a step portion (121) connecting the root (110) and the body (120), wherein the step portion (121) is inclined from the root (110) at a higher surface to the body (120) at a lower surface.

8. The fan blade (100) according to any one of the preceding claims, wherein the root (110) is formed with a hole, the hole defining a mounting point (111), the mounting point (111) being used to fasten a fastener therein to mount the fan blade (100) to the motor unit (200).

9. A ceiling fan, comprising: A motor unit (200); as well as A plurality of fan blades (100), the plurality of fan blades (100) being radially mounted on the motor unit (200), each fan blade (100) comprising: a root portion (110), the root portion (110) being used to mount the fan blade (100) on the motor unit (200); as well as a body (120), the body (120) extending from the root (110); The body (120) is formed with an elongated groove (130) extending along a rear edge (142) of the body (120).

10. The ceiling fan according to claim 9, wherein the elongated groove (130) comprises: an inclined portion (131), the inclined portion (131) being inclined from a portion of the body (120) adjacent to the root portion (110); as well as A flat portion (132) extends from the inclined portion (131) toward a free end (145) of the body (120).

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