From The Ergoweb® Learning Center

Ergonomics- Install Backglass From Outside – Glass Install


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.

Task Prior to Abatement (Description)

This is a fictitious job but reflective of common work situations on an auto assembly line.

Worker position: The worker walks to the truck and takes a position facing forward at the rear of the cab. The feet are supported on the longitudinal members of the dolly 46 inches apart and the low back is supported on the truck box.

Install glass: The worker is given the backglass from his coworker and positions it in place in the back of the truck. The glass is pressed in place from the outside while the coworker on the inside of the cab pulls out the molding string to seat the window. The worker assists in seating the window by pounding on the glass and aligning the molding with a feathering stick.

Task Prior to Abatement (Illustration)


Ergonomic Risk Factor (Force)

Pounding the glass with the hand is required to align and seat the glass.

Ergonomic Risk Factor (Mechanical)

Grasping the flat, thin handle of the feathering stick is required to use the tool to seat the window.

Ergonomic Risk Factor (Posture)

Extreme forearm twist (supination) and extreme wrist extension is required to grasp the glass.

Ergonomic Solution (Engineering Controls)

Use suction cups with D-ring handles to handle backglass to improve forearm and wrist posture.

Provide a plastic handle for the feathering stick with rounded corners to reduce mechanical stresses.

The diameter should be limited to 3/4 inch so that it can still be manipulated in the fingers.

Use palm pads to protect the hands while pounding window into position.

Use cement to hold the window in place.

Ergonomic Solution (Illustration)