2023 Inductee Cyril Keller: A Resourceful Innovator

At the National Inventors Hall of Fame^®, we are proud to recognize the world’s most impactful U.S. patent holders. Since 1973, in partnership with the United States Patent and Trademark Office, we have honored more than 600 visionary Inductees.

As we celebrate our 50th anniversary, we are excited to welcome our 2023 Inductee class – an inspiring group of innovators who have shaped our society. Among these exceptional inventors are Cyril Keller and Louis Keller, inventors of the Bobcat^® skid-steer loader. Read on to learn more about Cyril Keller and his lasting legacy of innovation and hard work.

A Groundbreaking Invention

Cyril Keller was born in Tintah, Minnesota, on April 8, 1922. He attended a country school near his home and had no formal education beyond grade 8. At age 20, he joined the U.S. Navy. Keller served on a ship and on the island of Saipan during World War II.

In 1953, Keller joined Keller Welding, the business his brother Louis had started in Rothsay, Minnesota, six years earlier. In 1957, local farmer Eddie Velo came to Keller Welding with a specific need that no existing machine could meet. He needed a light, maneuverable, self-propelled machine that could clear manure from the second story of his turkey barn. Determined to develop the right solution, the Kellers headed into their machine shop with materials including used mechanical parts from nearby junkyards and bars from the old Rothsay jail.

After just six weeks, the Kellers emerged from their machine shop with the Keller Self-Propelled Loader. The invention featured a front bucket, hydraulic foot pedals, a rear motor, two front wheels, a pivoting rear caster wheel that enabled sharp turns, and a belt-and-chain drive system. The Kellers later replaced the belts with their patented clutch system, added a counterweight in the back for stability, and designed attachments including a snow blower, sweeper, bucket and manure fork.

When the loader caught the attention of the Melroe Manufacturing Company in 1958, the Kellers were invited to exhibit their invention at the company’s booth at the Minnesota State Fair. At first, their potential buyers were unsure of the machine, particularly because it lacked a steering wheel. “You had to demonstrate it or you could not sell it,” explained Joe Keller, the son of Louis and nephew of Cyril Keller. The brothers’ successful demonstrations convinced buyers of the genius of their design.

Melroe was awarded exclusive manufacturing rights to the Kellers’ loader on a royalty basis. The manufacturing contract also required the Kellers to become Melroe employees, so the brothers sold their business and continued to develop their invention for Melroe.

A Worldwide Success

The first four-wheel, skid-steer loader, where the wheels skid for directional control, was introduced in 1960 as the M400. However, it bore equal weight on the front and back wheels, making it difficult to steer. So in 1962, Melroe introduced the M440 and called it the “Bobcat.” With 70% of its weight in the rear when the bucket was empty, and an equal amount in the front when the bucket was full, this model provided increased skid-steer maneuverability.

Cyril Keller set up dealerships throughout the United States and in Europe over the next several years, and he later ran a school to train new dealers in operating the Bobcat loader. At these training centers, he was known by the nickname “Sarge.”

In 1969, Clark Equipment Co. purchased Melroe’s agricultural products business for about $36 million. Ingersoll-Rand took over Clark in 1995, and in 2007 sold Bobcat for $4.9 billion to South Korea’s Doosan Group.

Today, compact loaders are ubiquitous on farms and at construction sites, railyards and seaports. More than 1 million Bobcat skid-steer loaders have been built and sold worldwide.

The American Society of Agricultural and Biological Engineers recognized the Kellers’ skid-steer loader as a Historic Landmark in 2004. The Keller brothers were inducted into the Association of Equipment Manufacturers Hall of Fame in 1999 and the Minnesota Inventors Hall of Fame in 2004.

The father of eight children, Cyril Keller died in 2020 at the age of 98. He and Louis had each earned six U.S. patents for their inventions.

Meet More Inspiring 2023 Inductees

To learn more about the visionary creators and innovators who make up our latest class of Inductees, we invite you to visit our website.