Dish-Washing Machine Unloading (25 points)

Job Description

A worker manually lifts trays of clean dishes from a conveyor at the end of a dish washing machine and loads them on a cart as shown in Figure 15. The trays are filled with assorted dishes (e.g., glasses, plates, bowls) and silverware. The job takes between 45 minutes and 1 hour to complete, and the lifting frequency rate averages 5 lifts/min. Workers usually twist to one side of their body to lift the trays (i.e., asymmetric lift) and then rotate to the other side of their body to lower the trays to the cart in one smooth continuous motion. The maximum amount of asymmetric twist varies between workers and within workers, however, there is usually equal twist to either side. During the lift the worker may take a step toward the cart. The trays have well designed handhold cutouts and are made of lightweight materials. The task variable data are measured and recorded on the job analysis worksheet (Figure 16). At the origin of the lift, the horizontal distance (H) is 20 inches, the vertical distance (V) is 44 inches, and the angle of asymmetry (A) is 30. At the destination of the lift, H is 20 inches, V is 7 inches, and A is 30. The trays normally weigh from 5 lbs to 20 lbs, but for this example, assume that all of the trays weigh 20 lbs.20 INCHES 44 INCHES 20 INCHES ORIGIN 30 SAGITAL LINE 7 INCHES DESTINATION 30"