GB2282645A

GB2282645A - Fan blade.

Info

Publication number: GB2282645A
Application number: GB9320891A
Authority: GB
Inventors: Yung-Chung Huang
Original assignee: TYGAR CO Ltd
Current assignee: TYGAR CO Ltd
Priority date: 1993-10-11
Filing date: 1993-10-11
Publication date: 1995-04-12
Also published as: GB9320891D0

Abstract

A fan blade A' has an elongated plate 10 which has an air confronting front face f and a back face b and which includes a longitudinal leading section 101, a longitudinal lagging section 103 with respect to a rotating direction of the elongated plate 10 and a longitudinal intermediate section 102 located between the leading and lagging sections 101, 103. The plane of the leading section 101 and the plane of the intermediate section 102 form an obtuse angle ( alpha ) therebetween, while the plane of the intermediate section 102 and the plane of the lagging section 103 similarly form an obtuse angle ( beta ) therebetween. The sections may define a stepped cross-section or may be curred (Fig 5) to form a wavy cross-section. The blade shape enables less driving power to be used. <IMAGE>

Description

FAN BLADE This invention relates to a fan blade, more particularly to a blade of a ceiling fan.

A conventional ceiling fan has a rotary shaft unit and a plurality of blades fixed inclinedly to the rotary shaft unit. Generally, each blade is formed with a flat face which strikes and fans air so as to induce air currents, thereby enhancing air circulation when the blade rotates by means of the rotary shaft unit. However, since the air resistance produced by such a flat blade is high, a large amount of electric power is required to rotate the blade. This is not economical.

Therefore, the objective of this invention is to provide an improved blade of a ceiling fan, which improved blade can be rotated with a smaller amount of electric power.

Accordingly, a fan blade of this invention is to be mounted on a rotary shaft unit of a fan and comprises an elongated plate which has an air confronting front face and a back face and which includes a longitudinal leading section, a longitudinal lagging section with respect to a rotating direction of the elongated plate and a longitudinal intermediate section located between the leading and lagging sections. The intermediate section extends and turns inclinedly and backwardly from the leading section. The lagging section extends and turns inclinedly and forwardly from the intermediate section. The plane of the leading section and the plane of the intermediate section form an obtuse angle therebetween. The plane of the intermediate section and the plane of the lagging section similarly form an obtuse angle therebetween.

Other features and advantages of the present invention will become apparent in the following detailed description of the preferred embodiments, with reference to the accompanying drawings, in which: Figure 1 is a schematic view of a first preferred embodiment of a fan blade of this invention.

Figure 2 is a top view of the first preferred embodiment of the fan blade.

Figure 3 is a side view of the first preferred embodiment of the fan blade.

Figure 4 is a partially sectional view of the first preferred embodiment.

Figure 5 is a partially sectional view of a second preferred embodiment of this invention.

Figures 1 to 4 show a first preferred embodiment of a blade (A') of a ceiling fan (not shown) according to this invention. The blade (A') is to be mounted inclinedly to a rotary shaft unit (not shown) of the ceiling fan in order to induce air currents for enhancing air circulation when the blade (A') rotates by means of the rotary shaft unit.

The blade (A') has an elongated plate 10 which has an air confronting front face (f) and a back face (b) and which includes a flat longitudinal leading section 101, a flat longitudinal lagging section 103 and a flat longitudinal intermediate section 102 located between the leading and lagging sections 101, 103. The intermediate section 102 extends inclinedly and backwardly from the leading section 101, and the lagging section 103 extends inclinedly and forwardly from the intermediate section 102 such that the elongated plate 10 has a stepped cross-section. The plane of the leading section 101 and the plane of the intermediate section 102 form an obtuse angle (a) therebetween. The plane of the intermediate section 102 and the plane of the lagging section 103 form an obtuse angle (ss) therebetween. The elongated plate 10 is preferably an integrally formed piece.

Due to the particular arrangement of the intermediate and lagging sections 102, 103, when air currents pass over the air confronting front face (f) at the leading section 101, the elongated plate 10 permits a greater amount of air, when compared to the conventional blade, to be guided backwards by the intermediate section 102 so as to move toward the lagging section 103, which hinders and sends forwardly said air, while the blade (A') rotates forwardly.It can be realized clearly with reference to Figure 4, wherein air currents which pass over the forwardly moving blade (A'), as shown by an arrow (A), at the leading section 101 along the air confronting front face (f), as shown by an arrow (B), are guided by the intermediate section 102 to flow toward the lagging section 103, as shown by an arrow (C), and are then hindered and sent forwardly by the lagging section 103, as shown by an arrow (D). In this way, the air resistance produced during operation is reduced in the present invention. Therefore, a smaller amount of electric power is required to rotate the blade (A').

This is more economical.

It is noted that the blade (A') which is mounted to the rotary shaft unit can rotate forwardly or backwardly to induce air currents. When the blade (A') rotates backwardly, the lagging section 103 is used as a leading end while the leading section 101 is used as a lagging end. At this time, air currents which pass over the back face (b) at the lagging section 103 are guided backwards by the intermediate section 102 so as to move toward the leading section 101, which hinders and sends backwardly the air currents.

Furthermore, the blade (A') of this invention can be mounted to the rotary shaft unit of the ceiling fan in a horizontal position instead of an inclined position as required in conventional fan blades.

Figure 5 shows a second preferred embodiment of the blade (B') of a ceiling fan according to this invention. The blade (B') has an elongated plate 10' which has an air confronting front face (f') and a back face (b') and which has a wavy-like cross-section. The elongated plate 10' also includes a longitudinal leading section 101', a longitudinal lagging section 103' and a longitudinal intermediate section 102' located between the leading and lagging sections 101', 103'. The intermediate section 102' extends backwardly and turns smoothly from the leading section 101'. The lagging section 103' extends forwardly and turns smoothly from the intermediate section 102'.

When a ceiling fan is provided with the blades according to the present invention, it can induce air currents with a smaller amount of electric power when compared to a ceiling fan that is provided with conventional flat blades. When a same amount of electric power is supplied, the blades of this invention can induce a larger amount of air currents than that induced by the conventional flat blades. In addition, due to the formation of the stepped crosssection or the wavy-like cross-section of the elongated plate 10, 10', the fan blade A', B' does not deform easily.

Claims

CLAIMS:

1. A fan blade to be mounted on a rotary shaft unit of a fan, comprising an elongated plate which has an air confronting front face and a back face and which includes a longitudinal leading section, a longitudinal lagging section with respect to a rotating direction of said elongated plate and a longitudinal intermediate section located between said leading and lagging sections, said intermediate section extending and turning inclinedly and backwardly from said leading section, said lagging section extending and turning inclinedly and forwardly from said intermediate section, a plane of said leading section and a plane of said intermediate section forming an obtuse angle therebetween, the plane of said intermediate section and a plane of said lagging section forming an obtuse angle therebetween.

2. A fan blade as claimed in Claim 1, wherein said elongated plate has a stepped cross-section

3. A fan blade as claimed in Claim 1, wherein said elongated plate of said fan blade has a wavy-like cross-section, said elongated plate turning smoothly from said leading section to said intermediate section and from said intermediate section to said lagging section.

4. A fan blade substantially as hereinbefore described with reference to the accompanying drawings.