Homer Eaton. Source: Hexagon Metrology

The Romer articulating arm was introduced more than 35 years ago. In the mid-1970s, a California technology company called Eaton Leonard Corp. designed an arm-shaped instrument for tube inspection that could capture the shape of a 3-D object such as an exhaust pipe. In 1973, Homer Eaton, founder of Eaton Leonard, patented a multi-axis articulated arm for tube inspection work. Years later in 1986, Eaton and Romain Granger partnered to start Romer SARL (Romer France), introducing a portable articulated arm to the metrology marketplace. The timing was nearly perfect with the advent of the computer, and the 3-D measurement needs of the aerospace and automotive industries were rapidly emerging to create demand for such a product.

Eaton, now retired, has been a lifelong inventor and entrepreneur. He has been involved with the research and development of measurement and inspection hardware, electronics and software for the entirety of his career. In a recent interview, Eaton shared his discoveries and the progress of the articulating arm during the span of more than three decades.

What problem were you trying to solve when you conceived the Vector 1? [The Eaton-Leonard Vector 1 arm for tube inspection, built circa 1973, was the original articulating arm invention and predecessor to the Romer arm.]

Eaton:I was trying to measure the geometric path of a bent tube shape, rather than the difficult convention of measuring the component features of lengths and angles.

What level of precision where you looking to achieve?

Eaton:I was looking to achieve an accuracy of 1/32 inch-0.8 millimeter.

Did you envision the product as a solution for mainstream metrology applications?

Eaton:No, I did not.

At what point did you decide to make the jump from inspection of tubes to other components?

Eaton:In 1974, George Goodreau, plant manager at Westinghouse, inspired me to build units for measuring steam turbine blades on the shop floor. We built a number of roll-around arms for this purpose.

When did you realize this technology could be a portable device?

Eaton:In the late ‘80s, Romain Granger convinced me that we could build an even lighter unit and fold it into a more compact shape by adding one more axis. It was about this same time Toshiba introduced the portable computer.

What were the main initial impediments to portability?

Eaton:There were three distinct roadblocks:
    1. Having a portable computer. The Vector 1 minicomputer weighed 40 pounds.
    2. Being outcasts from the CMM world in a world of granite, walls and arrogance.
    3. Needing a rigid support base for the arm.
What do you consider to be the most interesting application for the arm that you’ve seen?

Eaton:Measuring a Steinway piano and letting metrology into the world of art.

Were there any huge “A-Ha!” moments in the history of the product that you remember in particular? If so, what were the circumstances surrounding them?

Eaton:Yes, there [were]. The first was simultaneously measuring a point and a vector, and this was the origin of the Vector 1, an articulating arm for measuring bent tube shapes. The second moment was the Infinite rotation where we digitized raw encoder signals and transmitted digital data through slip rings. And lastly was the GridLok concept of the arm with virtually no hardware, just a mathematical feat.

Which do you prefer to invent: hardware or software?

Eaton:Hardware. It is more tangible, challenging and creative.

Your volumes of notebooks of ideas are somewhat legendary at Romer. How many things in those notebooks do you suppose actually turned into products or product enhancements?

Eaton:My notebook ideas turned into hardware, electronics, software...well over 50 products in the long run.

Where do you draw your inspiration from?

Eaton:Stress...the mother of innovation!

What were the most difficult design challenges throughout the history of the arm products?

Eaton: The main challenges were the twisting of the wires at the arm joints and the elimination of the mechanical coupling between the encoder and the arm axis.

Thinking back over the entire history of these products, what feature or product are you the most proud of?

Eaton:Definitely arm calibration. Creating the mathematical algorithms and artifact techniques for calibrating the arm was the fundamental basis for our success.

You’ve now seen the latest fruit of your legacy-the Infinite 2.0. What was your reaction to that product?

Eaton:I was immensely proud that this was accomplished by my people and without me!