The History of the Phillips Screwdriver
32 years ago the Phillips screwdriver was patented by Henry F. Phillips who was a Portland, Oregon, businessman.
from Wired
Phillips wasn't trying to make life with hand tools easier. He was trying to solve an industrial problem. To drive a slot screw, you need hand-eye coordination to line up the screwdriver and the slot. If you're a machine -- especially a 1930s machine -- you ain't got no eye, and your hand coordination may depend on humans.
The Phillips-head screw and Phillips screwdriver were designed for power tools, especially power tools on assembly lines. The shallow, cruciform slot in the screw allows the tapering cruciform shape of the screwdriver to seat itself automatically when contact and rotation are achieved. That saves a second or two, and if you've got hundreds of screws in thousands of units (say, cars), you're talking big time here.
And not only does a power Phillips driver get engaged fast, it stays engaged and doesn't tend to slide out of the screw from centrifugal force. Another advantage: It's hard to overscrew with a power tool. The screwdriver will likely just pop out when the screw is completely fastened.
