# US 6,719,533 B2 · High efficiency ceiling fan

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- Number: US 6,719,533 B2
- Document ID: US6719533B2
- Status: Granted
- Kind: B2
- Application number: 10/223,333
- Filed: 2002-08-16
- Published: 2004-01-15
- Granted: 2004-04-13
- Earliest claimed: 2002-07-11
- Assignees: Hunter Fan Company
- Inventors: Gregory Michael Bird
- Web page: https://patentgrep.com/patent/US6719533B2

## CPC

- F04D 25/088: {Ceiling fans}
- F04D 29/384: {characterised by form}
- Y10S 416/05: Variable camber or chord length
- F04D: NON-POSITIVE-DISPLACEMENT PUMPS (engine fuel-injection pumps F02M; ion pumps H01J41/12; electrodynamic pumps H02K44/02)
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

## Abstract

Ceiling fan energy consumption efficiency is enhanced with fan blades that have an angle attack that decreases from root end to tip end at higher rates of decrease nearer their tip ends than at their root ends. Air flow distribution is enhanced with at least a portion of the blades having a dihedral that continuously increases. Efficiency on downdraft is also achieved with the blades having concave top and bottom surfaces.

## Claims

### Claim 1

A ceiling fan having a plurality of fan blades mounted for rotation about an upright fan axis of blade rotation and with each fan blade having two elongated side portions that straddle an elongated central portion, and wherein each blade has a concave top surface and a concave bottom surface so that said central portion of each blade is thinner that its two side portions.

### Claim 2 (depends on 1)

The ceiling fan of claim 1 wherein the thickness of each blade along its centerline is approximately 25% thinner than the maximum thickness of said side portions.

### Claim 3 (depends on 1)

The ceiling fan of claim 1 wherein said two side portions and said central portion of each blade extend substantially from the root end of each blade to its tip.

### Claim 4

A ceiling fan having a plurality of fan blades mounted for rotation about an upright fan axis of blade rotation and with each fan blade having two elongated side portions that straddle an elongated central portion, and wherein said central portion of each blade is thinner that its two side portions and wherein each of said fan blades is curbed upwardly towards its tip end to have a continuously graduated dihedral.

### Claim 5 (depends on 4)

The ceiling fan of claim 4 wherein each blade has a dihedral of approximately 0° at its root end and a dihedral of approximately 10° at its tip end.

### Claim 6 (depends on 4)

The ceiling fan of claim 4 wherein each blade has a greater angle of attack proximally said fan axis than distally said axis and with the rate of change in angle of attack therebetween being non-uniform.

### Claim 7 (depends on 6)

The ceiling fan of claim 6 wherein each blade has a dihedral of approximately 0° at its root end and a dihedral of approximately 10° at its tip end.

### Claim 8

A ceiling fan having a plurality of fan blades mounted for rotation about an upright fan axis of blade rotation and with each fan blade having two elongated side portions that straddle an elongated central portion, and wherein said central portion of each blade is thinner that its two side portions and wherein each blade has a greater angle of attack proximally said fan axis than distally said fan axis and with the rate of change in angle of attack therebetween being non-uniform.

### Claim 9 (depends on 8)

The ceiling fan of claim 8 wherein each blade has a dihedral of approximately 10° at its tip end and an angle of attack of approximately 10° at its tip end.

### Claim 10

A ceiling fan having a plurality of fan blades with a concave upper and a concave lower surfaces opposite said concave upper surface mounted for bidirectional rotation about an upright fan axis of blade rotation.

### Claim 11 (depends on 10)

The ceiling fan of claim 10 wherein said upper and lower blade surfaces have substantially the same topology.

### Claim 12 (depends on 11)

The ceiling fan of claim 11 wherein each blade is curved upwardly towards its tip end to have a continuously graduated dihedral.

### Claim 13 (depends on 11)

The ceiling fan of claim 11 wherein each blade has a greater angle of attack proximally said fan axis than distally said fan axis with the rate of change in angle of attack therebetween being non-uniform.

### Claim 14

The ceiling fan of claim wherein each blade has a greater angle of attack proximally said fan axis than distally said fan axis with the rate of change in angle of attack therebetween being non-uniform.