ROK

Rockwell Automation, Inc.

A maker of industrial automation gear and software, this is one of the world's largest pure-play companies in the field. Its products—brands like Allen-Bradley, ControlLogix, PowerFlex, and FactoryTalk—help factories run everything from car assembly lines and food plants to mines. It began in 1903 when Lynde Bradley and Dr. Stanton Allen founded the Compression Rheostat Company in Milwaukee to control electric motor speeds; it was later bought by Rockwell International and renamed Rockwell Automation in 2001. Fun fact: its roots trace to a carbon-disc motor controller that launched a whole industry of factory automation.