Case Study

 


Case Study

Aircast/Mayo Clinic Elbow Brace

Aircast develops and manufactures orthopedic devices for the functional management of injuries. For over 30 years, Aircast has provided scientifically based innovative solutions to improve medical outcomes and achieve total customer satisfaction.

Aircast approached Ikona Gear in January 2004 on the recommendations of their mechanical designers, Ion Design. The brace is used immediately after surgery to protect and immobilize the elbow joint. For static stretch, the control knob (with gear inserted within) is set to the desired degree of flexion/extension, allowing the elbow to flex through a normal range of motion without applying muscular tension, thus minimizing the inflammatory response that can occur in dynamic stretching. The designers and Aircast had experienced a problem with their first gearing application that was resulting in a "skip" in the gear during the flexion and extension, leading to patient discomfort.

Ikona was presented with the original gear set, made from Delrin plastic, with an outside diameter of the gear assembly of approximately 2 inches. We had a limited envelop within which to replace a gear-set which had a ratio of 24:1, and a tooth contact ratio of less than 1.

Ikona developed a new patented Ikona gear set with a ratio of 30:1, and a contact ratio of 3.07. Materials and diameters had to be kept the same in order to avoid major changes to the other components. Our centre distance was slightly different but didn't effect the outside diameter of the gears.

Our Ikona gear-set was delivered to Ion Design within a month where it was tested. Their test results showed a 210% load improvement, which was sufficient to allow the gear to withstand the normal weight and torque applied to this small plastic gear-set. The end result was a successful elbow brace, no skipping of the gear, and the endorsement of the Mayo Clinic.