Task Prior to Abatement (Description)
This is a fictitious job but reflective of common work situations on an auto assembly line.
Worker position: Two workers are on each side of the assembly line wearing heavy gloves.
Apply sealant: The workers reach overhead for sealant guns. Sealant is applied in a continuous motion starting at the top center of the windshield frame, traveling outward along the frame and ending at the bottom center. The sealant guns are released by the workers and pulled upward by retractors for storage.
Install Molding: Molding is taken from a rack by one worker and passed over the hood to the other worker. The molding is secured at the top sides of the window and seated in the frame through a series of gripping, pushing, and rocking hand motions.
Task Prior to Abatement (Illustration)
Ergonomic Risk Factor (Force)
Finger pinching and wrist twisting are required to apply the molding.
The use of poor fitting gloves requires greater hand strength to manipulate the molding.
Ergonomic Risk Factor (Posture)
Extreme internal rotation of the arm and pronation of the forearm is required to apply the sealant properly along the frame with the sealant gun.
Extreme reach is required to install molding along top-center of the windshield.
Ergonomic Solution (Engineering Controls)
Change the sealant gun nozzle so that the gun can be rotated as the sealant is applied. This reduces the extreme postural positions required of the upper extremity.
Apply the sealant in three motions: top to side, top to bottom, and bottom to side. This allows the wrist and forearm to be straightened between moves.
Maintain close tolerances on molding dimensions.
An over or undersized molding requires more physical effort to install.
Use cement to hold windshield in place instead of the current rubber molding system.
Maintain an inventory of numerous gloves in various sizes and styles so that each worker can select the glove that feels the most comfortable.
Ergonomic Solution (Illustration)
Armstrong, Thomas J.; Fine, Lawrence J.; Joseph, Bradley; and Silverstein, Barbara. Analysis of Selected Jobs for Control of Cumulative Trauma Disorders in Automobile Plants. Ann Arbor, Michigan: The University of Michigan, 1984.