He literally lies prone on the belt and is dragged, swallowed and eaten up by the whizzing wheels, gears, and cogs of the monstrous machine.
His body snakes its way through the gears until the production line's direction is reversed and he finally emerges free of the machine. In a trance-like state, with wrenches aloft, he demonically tightens everything in sight, including people's noses.
Special sound effects and an original musical score (by composer Chaplin, including various musical themes from "Hallelujah, I'm a Bum," "Prisoner's Song," "How Dry I Am," and "In the Evening By the Moonlight") enhance the pantomime.
Set in the 1930s during the Great Depression era, the film's main concerns (and those of the oppressed Tramp) echo those of millions of people at the time - unemployment, poverty, and hunger.
The boss has ordered production increases: "Section 5 - give 'em the limit," so the conveyor belt is sped up - a hilarious, frenzied scene as the Tramp makes an heroic effort to keep up.
Under the strain of the job, he finally goes beserk, slowly driven insane and engulfed by the assembly line.
The results of his innocent, personal behavior have much larger consequences.