Cyril and Louis Keller
Cyril and Louis Keller are responsible for the invention of the skid steer loader. They owned and operated a repair and fabrication shop in Minnesota and eventually developed a machine that would become one of the most widely used pieces of industrial equipment.
 Keller Manufacturing
Cyril Keller was born in 1922 and his brother Louis was born a year later.
In the fall of 1947, younger brother Louis started his own general repair and fabrication business, Keller Manufacturing in Rothsay, Minnesota. During the early years, Louis developed the first single stage ribbon auger snow blower. Designed in 1949, the snow blower was an attachment designed to fit on either a John Deere or WD45 Allis-Chalmers tractor. He applied for a patent for his attachment and arranged for a company called Farmhand to sell them. However, Louis’ patent application was filed too late, only allowing Farmhand to produce a few on a royalty basis for a limited time.
Louis partnered with his elder brother Cyril in 1953.
 Developing the Skid Steer Loader
One of the Kellers' regular customers, Eddie Velo, came to the brothers in 1956 with a problem. Velo was a turkey farmer looking to expand his flock and utilize a two-floor barn to house them. However, he needed a lightweight maneuverable machine to clean the turkey manure out of his large barn.
So the Kellers designed a drive system that could provide the necessary maneuverability. They brought it to Velo for his approval and a possible manufacturing agreement for a usable loader. Velo agreed to pay manufacturing costs if the loader worked; otherwise, the Keller’s would forfeit their labor fee and only receive the cost for parts.
On February 4th, 1957, the first loader was completed and prepared for testing in Velo’s barn. It was a front-loading, three-wheeled vehicle with a rear caster wheel, able to turn around its own length. It was also light enough to be carried to the second floor. “The loader surpassed expectations from the start.” However, testing showed some weakness in the drive system and its use of belts and pulleys. So, they designed a new clutch system that eliminated the belts and installed it into the new loader.
After successful tests, the Kellers decided to manufacturer the loaders for public sale. Six new loaders, powered by 6.6 horsepower Kohler Engines, were sold to various turkey farmers. By this time Louis and Cyril were searching for ways to mass-produce their loader. They lacked the funds to start the process themselves so they approached the bank of Rothsay, Minnesota, who were willing to supply them some of the $250,000 they needed. They also approached the City of Fergus Falls, Minnesota, who were willing to provide money, but required partial ownership of the Kellers’ patent, which they unwilling to part with.
 Melroe Manufacturing Co.
Understanding their search for money, the Kellers’ uncle, Anton Christianson, introduced them to Les Melroe of Melroe Manufacturing Co. in Gwinner, North Dakota. Les Melroe stopped by the Kellers workshop when they were replacing the belt drive on Eddie Velo’s loader with their new, patented clutch drive. He saw the product they were looking to market and suggested they bring it to the Minnesota State Fair and display it for the public. Melroe showcased the loader in his booth, not planning on selling it, but instead speaking to the public to get their opinion of the machine. The reaction was so positive that by the third day on display Les placed Melroe decals all over the Keller loader saying “If people want a machine that bad, Melroe is going to have it.”
They made an agreement whereby Melroe would purchase the exclusive manufacture rights on a royalty basis. Melroe also hired the Kellers to continue developing the loader. Together, Louis and Cyril rented an apartment in Gwinner, North Dakota, commuting home to Rothsay on weekends.
The Kellers began developing the first Melroe loader prototype in 1958, completing it by 1959. It retained much of the original Keller design: patented clutch drive, two independently operated front drive wheels, rear caster wheel, two-level steering, with the bucket and lift arms controlled by foot pedals. It also incorporated a nine horsepower AENL Wisconsin engine. Although the model was quite similar in many respects to original Keller loaders the Melroe manufacturing facilities allowed the machine to look more professional and be constructed of much stronger, more reliable materials.
After significant testing, the new Melroe loader went into production. Cyril Keller went on the road as a loader salesman while Louis remained in Gwinner to continue development.
Louis decided to relocate his family to Gwinner, ND. Cyril kept his family in Minnesota since he was busy on the road selling loaders.
Louis continued with Melroe Manufacturing developing a series of successively advanced skid steer loaders. Melroe would eventually change their company name to Bobcat, after a series of Louis Keller developed loaders.
 After Melroe Manufacturing
Louis Keller left Melroe Manufacturing in 1967 to pursue other interests including designing tracks for skid steer loaders. He developed a set of tracks called Tire Tracks, which were manufactured by Loegering Manufacturing Inc., a company owned by his daughter Marilyn and her husband George Loegering.
Cyril Keller eventually conducted Bobcat training schools in Gwinner and San Antonio until his retirement in 1982. However, even in retirement Cyril continued to invent. He designed the Squirrel Show Swing Feeder, which requires the squirrels to perform gymnastics routines in order to be fed. Two of his sons sell his feeder in Pelican Rapids, Minnesota.
Both Kellers have also worked on inventing equipment for ice fishing.
Louis Keller died on July 11, 2010 at the age of 87.
- Keller, Joe. How the Bobcat Ski-Steer Loader Came to Be, 2008-09-25.
- Melroe: Fathers of invention / Born to become a Bobcat, 2008-09-25.