Comfortable Working Area of Seated Operators.

Abstract

Comfortable working area for knob and lever controls was developed to modify the concept of conventional working area. A proposed working area based on the actual working comfort of an operator avoids dichotomy which is the reachability of control devices, and shows a distinct shape compared with existing normal working area following the Farley's concept. It is shown that the distance from the body to control devices and the slope of a work table have the quadratic effect to working comfort, and that the most comfortable area for the controls is located at the distance of about 2-4cm in the sagittal direction and about 42-43cm in the frontal direction from the shoulder respectively, which is located outside the existing normal working areas. The result of the response surface analysis indicates that a little slope of the control panel, about 15°, improves the working comfort. From the study, it was found that the working comfort varies within the working area even if each position is equally far from the body. It is suggested that the conventional normal working area needs to be refined based on the actual working comfort. Moreover, the comfortable working area could differ from control to control, and the primary working area souhld be determined by the type of a control. It is expected that the isocomfort working area generated in this study is used as a useful guideline for control panel layout.