Abstract
The production in TFT-LCD (Thin Film Transistor-Liquid Crystal Display) industry involves heavy manual materials handling with the aid of manual vehicles, such as carts, trucks, and so on. Thus the design and usability of manual vehicles become an important issue. This study includes two phases, i.e. experiment I and experiment II. Both experiments are nested factorial design. For the experiment I, gender (male, female), handel height (88 cm, 101.5 cm, 115 cm, 135 cm), direction of motion (push, pull) and stances (feet side-by-side, one in front of the other) were the independent variables. The dependent measures were force exertion and step. Besides, we also evaluated maximual force exertion on subject's prefer handel height and stance. The results indicate that handle height to be set at 115 cm or 135 cm, and pushing with one foot in front of the other can exert maximual force. Futhermore, males exerted higher force than females.Experiment II involves two parts, i.e. large and small carts. For the experiment design, handle height (88 cm, 101.5 cm, 115 cm), type of operation (push, pull) and load (empty, full) were the independent variables. Besides, force exertion, EMG, subjective discomfort rating and cart related questionnaire were the dependent measures. The size of wheels (6 inch, 8 inch) were considered in small cart experiment. The results indicate that handle height should be set at 115 cm, wheels with the diameter of 6 inches and operated by pushing are recommended. Moreover, it is also recommended to assign male operators to manipulate the carts.