As the Gear Turns - History

One of the gear industry’s most important innovators.

With the close of 2013 and the start of 2014, we would like to reflect on one of history’s key moments of technological innovation that shaped today’s gear industry.

In 1958, the American inventor and self-taught engineer, John T. Parsons, was granted a patent for a “motor controlled apparatus for positioning [a] machine tool.” Before this time, complex curved geometries were estimated using a small number of coordinates and French curves to generate a template from which operators could machine parts. With the help of Frank Stulen, their patent led to the “Card-a-matic Milling Machine,” as they first named it. Parsons and Stulen developed the first numeric controlled machine tools to manufacture highly sophisticated geometries of the time. This included helicopter rotor blades, which were machined using a large number of mathematically accurate coordinates. IBM punch cards first controlled the machines’ axes, and this later changed to a digital processor using vacuum tubes. Parsons worked with the Massachusetts Institute of Technology to provide servomotors for the machines to move ballscrews. Unfortunately, punch cards had limitations. These limitations were overcome with paper punch-tape that had the capability of achieving 15 ipm feed rates. These machines revolutionized the manufacturing industry, which at the time was slow to see the huge potential in “numeric control.”

Today, the Society of Manufacturing Engineers calls Parsons, “the father of the second industrial revolution,” due to his innovations combining computer processes with machine tools. Thanks to him, we now benefit from the accuracy, flexibility, and speed of computer numeric controlled manufacturing machines.

Figure 1: Excerpt from Parsons's Patent

Figure 1: Excerpt from Parsons's Patent