Originally designed in 1997 for the ambulatory elderly, the Autumn Chair incorporates many features to accommodate this population, but is also a success in Universal Design.
"Universal Design is defined as the design of products and environments to be usable by all people, to the greatest extent possible, without the need for adaptation or specialized design," says Alan Harp, industrial designer for Georgia Tech's Advanced Wood Products Laboratory. "By designing for comfort and ease of ingress and egress for the elderly, the chair has been found to be extremely comfortable to the average population."
The Autumn Chair was the AWPL's first research project utilizing the technology available at the lab.
The Autumn Chair Project was developed through research performed at Georgia Tech's Center for Assistive Technology and Environmental Access through the initiative of CATEA director Joseph Koncelik. "The motivation for this project came from a need to demonstrate the capability of advanced wood processing machinery and also to create a product that exemplified the mission of the center," says Koncelik.
The specific features of the chair that speak to the ideals of universal design and the benefit it provides are:
Extended armrests with elbow relief: The extended armrest provides a solid grasp of the chair as one approaches or leaves the chair, an important feature to prevent falls and to assist in egress. The elbow relief prevents pinching of the ulnar nerve while seated.
Lower seat height: Seat height is 16 inches from the floor, one inch lower than typical. This provides a height that can accommodate a much greater percentage of the population.
Sculpted seat pan: The formed seat disperses the pressure points to create a very comfortable sitting area.
Wide footprint: The 23-inch-wide by 24-inch-deep footprint makes the chair extremely difficult to tip.
Integral lumbar support and curved back: The design of the back with its deep curve and radiused part design cradles the back and provides great support for the lower back.
To highlight these principles of Universal Design, the Autumn Chair was chosen to be featured at the 1998 Unlimited By Design Exhibition at the Smithsonian's National Museum of Design in New York.
An aspect of the chair that garners attention at first glance is the leaf inlay in the seat of the chair. The image is of a maple, oak and cherry leaf fashioned in their respective species of wood. "As with many successful designs, the leaf inlay was created as a method to disguise a flaw," says Harp.
During construction of one of the original hand-built prototypes, a large knot appeared as the seat was being sculpted. Lacking the resources to make another seat blank, the design team created the inlay to cover the knot so as to preserve the work already completed. The inlay has now become one of the most eye-catching elements of the Autumn Chair.
Harp completed the initial CNC prototype in August 2001 as the subject of his Master of Science degree through Georgia Tech's Industrial Design program. A short test run utilizing six different species of wood has also been completed to investigate the relationship of wood properties as it relates to CNC machining. The species used were red oak, black cherry, yellow poplar, southern yellow pine, soft maple and plantation-grown mahogany. It was found that cherry and oak performed the best overall, with mahogany and maple following closely in terms of machinability without tear-out and splintering. The poplar and pine both proved to be problematic.
The chair was designed as a 3-D Solid Model on AutoCAD 2000, and then transferred into AlphaCAM to create the G-code required by the SCM Routech 250 three-axis CNC router to create the individual parts. Because the CNC router uses vacuum and friction to hold the parts, it was found that the variation of the solid wood required custom spoilboards to be created for each part. Harp used sandpaper as a friction agent and gaskets just inside the perimeter of the part to concentrate the vacuum, allowing all the parts to be held securely in place without the need for mechanical fastening to the machine.
During the early stages of the small test run, the idea of the rocking chair was brought up by popular demand of people touring AWPL. "The creation of the rocking chair is a good example of the advantage of designing in CAD and producing parts on CNC machinery," says Harp.
Harp was able to design and fully prototype the rocking chair in less than one day because of the ability to quickly adapt drawings already on file.
"The direct translation from a 3D Solid Model to an actual part creates highly accurate parts unmatched by conventional methods," says Harp. "The CNC technology can also manufacture parts with extremely high accuracy and repeatability.
Creating the chair parts on the CNC router was about 12 times faster than traditional methods."
AWPL is currently investigating the potential for production and marketing of the chair and rocker.
The mission of Georgia Tech's Advanced Wood Products laboratory is to move U.S. production of finished products using wood and wood composite materials into an internationally competitive position. The three components of the mission are research and development, education and training, and demonstration. For more information on the chair visit the AWPL Web site.