Abstract
Previous studies of handle evaluation have mainly examined optimal sizes of simple-shape (e.g., cylindrical) handles. The present study was intended to identify main design factors and to evaluate usability of vacuum cleaner handles which have complex design features. Upper part length (UL), midpoint-pipe centerline distance (MCD), tilt angle (TA), and cross-section upper part curvature radius (UR) of handle were determined as main design factors of vacuum cleaner handle. The effects of the four design factors on motion, muscular effort, and satisfaction in a front-to-back vacuuming task were evaluated using 6 handles by 36 participants aged in 20s to 50s. The ergonomic evaluation showed that the comfortable range of motion (CROM) deviations of small TAs (40.6° ~ 46.6°) were 1.8% higher significantly in abduction/adduction of shoulder, 2.6% lower in flexion/extension of shoulder, 1.6% lower in ulnar/radial deviation of wrist compared to those of large TAs (56.6° ~ 64.7°). Furthermore, % MVC < 5% of small URs (4.9 ~ 13.3 mm) was 1.7% higher significantly in deltoid, 3.0% higher in flexor carpi radialis compared to those of large URs (17.8 ~ 19.9 mm). Significantly higher satisfaction levels were reported in long ULs (118.4 ~ 154.8 mm) than short ULs (68.7 ~ 98.2 mm) and in short MCDs (3.0 ~ 25.8 mm) than long MCDs (39.4 ~ 78.4 mm). The results of this study can be used to develop ergonomic handles of vacuum cleaner.