Ergonomic case study for workers who install backglass from outside. This is a fictitious job but reflective of common work situations on an auto assembly line.
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.
The worker uses a push-rachet screwdriver to install screws in the cargo light above the window on some models.
The narrow handle of the push-rachet screwdriver causes concentrated pressure on hand tissues.
Extreme ulnar deviation of the wrist is required to operate the push-rachet screwdriver.
Use a spherical handle on the end of the screwdriver to spread the load over the largest possible area. The spherical ball design will also reduce the ulnar deviation of the wrist.
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.