The Infinity Fan

A Novel Spherical Four-Bar Mechanism (Dees, Ketchel, Larochelle)

The Infinity Fan (U.S. Patent #6213715) was designed and fabricated by Stacy L. Dees and John S. Ketchel under the supervision of Dr. Pierre Larochelle with the support of a Research Experiences for Undergraduates supplement to grant #DMI9612062 from the National Science Foundation. The purpose of the supplemental research grant was to design and prototype a working spherical four-bar mechanism, which is The Infinity Fan. The Infinity Fan is designed to be either a desk top or standing fan with motion in both the vertical and horizontal directions. The motion that the spherical mechanism produces makes the fan face move in an "infinity" or sideways figure-eight pattern upon a spherical surface. The fan spans 80 degrees in the horizontal plane and 40 degrees in the vertical plane. This path was developed to circulate the air in a room with the fan placed in a corner. The complex motion of the fan is actuated by only one motor. Therefore only one motor is needed to drive the spherical mechanism. A second motor is included in the fan head to drive the fan blades. The mechanism was designed using Sphinx1.2. Sphinx calculates all possible mechanisms, given four desired orientations of the fan head. The candidate mechanisms generated by Sphinx were sorted through until one was selected by the designers. The mechanism data (link/arc lengths, etc.) was then entered into SphinxCAM, an AutoLisp program written to layout the links in AutoCAD. The AutoCAD drawings were then imported into MasterCAM to generate NC code, and the links were manufactured using a three axis CNC machine. The mechanism was machined entirely by the students. The Infinity Fan design was entered into two ASME International competitions (the 1998 ASME National Student Mechanism Design Competition and the 1998 ASME National Student Manufacturing Design Competition) receiving fourth placement in both.