Ergonomic Knob Design Validation for Improved Musculoskeletal Comfort

Abstract

Ergonomic control devices can minimise risks of hand-related injuries. The pinch force exerted on a control knob during operations can be minimised so that excessive physical stress and strain on the hands are reduced. This improves working performance. Studies indicate that milling machine control knobs are difficult to operate. Hence, this study aims to validate an ergonomic knob design against a milling machine knob design to determine the extent of musculoskeletal comfort improvement. An ergonomic knob is designed based on a knurled spherical knob with ergonomics features. A validation is performed by requesting 12 participants to turn the knobs in clockwise and counterclockwise directions. Pinch force data is recorded. Findings show that the ergonomic knob reduces more than 55 % of pinch force compared to the milling machine knob replica. This study is useful for machine designers in the development of safer and more ergonomic knobs for various equipment, apparatus and devices.