Robust Design of Sounds in Mechanical Mechanisms

Current practices for creating a desired sound by a mechanical mechanism are irrelative design-build-test processes. It seems that very little guidance is available relating design to the sound output. The focus of this study was to identify, which parameters that affect the sound output of a click mechanism consisting of a toothed rack and a click arm.

First several geometries of the teeth and the click arm’s head were investigated to identify the most robust and repeatable design. It was found that a flat surface in the valleys between the teeth is very beneficial in relation to repeatability. Design of Experiments was used to identify the sensitivity of all the dimensions of the parts.

Here, it was found that many dimensions have an impact on the response e.g. the arm length, the tooth height and the gap between the parts. The results provide a useful basis for a sound-design guide for click mechanisms.