Hollow blades for ceiling fans

#1. Field of the Invention

#The present invention relates to blades for ceiling fans and particularly to blades with a hollow interior for ceiling fans.

#2. Description of the Prior Art

#FIG. 1A is a perspective view of a first embodiment of the invention.

#FIG. 1B is a cross section taken along line A—A in FIG. 1A.

#FIG. 2A is a perspective view of a second embodiment of the invention.

#Refer to FIGS. 1A and 1B for a first embodiment of the invention. The hollow blade 1 for ceiling fans according to the invention is made from a selected material and is formed with a hollow interior structure and a desired shape. The blade 1 has a tangent surface 11 and a supporting surface 12 opposing to the tangent surface 11 and a fastening section 13 for fastening to a ceiling fan (not shown in the drawings). When the blade 1 is mounted and assembled to the ceiling fan (not shown in the drawings), as the blade 1 is hollow and has a lighter weight, loading on the motor is decreased, hence electric power consumption also is reduced. Moreover, the hollow structure of the blade 1 consumes less material than conventional solid blades and also saves material costs.

#Refer to FIGS. 2A and 2B for a second embodiment of the invention. The blade 1 has a pilot edge 111 formed on the tail end of the tangent surface 11 for channeling wind direction. Refer to FIGS. 3A and 3B for a third embodiment of the invention. The blade 1 has a pilot edge 111 formed on the tail end of the tangent surface 11 and another pilot edge 111′ formed on the head end of the tangent surface 11, thus the blade 1 may channel wind direction when the ceiling fan motor rotates in either positive or reverse direction.

#Refer FIGS. 4A and 4B for a fourth embodiment of the invention. The tangent surface 11 and the supporting surface 12 are formed with selected curvatures for channeling wind direction. Refer to FIG. 4C for an embodiment variation according to FIG. 4B. As the blade 1 is hollow, and the tangent surface 11 requires a certain strength to withstand wind pressure without incurring deformation, and the supporting surface 12 provides the tangent surface 11 a supporting tension force. The supporting surface 12 has limited tension force and the curvature center of the arched tangent surface 11 subjects to the greatest pressure. As a result, the blade tends to incur deformation when the tangent surface 11 is under wind pressure. Hence in this embodiment, a plurality of reinforced ribs 14 are formed in the hollow space to bridge the tangent surface 11 and the supporting surface 12. Such a structure not only enables the tangent surface 11 to withstand force without deformation, can also disturb air and channel wind direction.