Today in motorcycle history, August 20, 1963
For the third time in nearly four years, Charles Fehn applies for a patent for his Rokon Trail-Breaker motorcycle.
The tale of the Trail-Breaker two-wheel-drive motorcycle can be traced back to 1958 in San Bernardino, California, when Charles Fehn began work on his invention, a "Motorcycle for slow cross-country travel over obstructions and in mountainous regions, and over snow and soft ground". A bit of a long-winded title but, it was the birth of the Trail-Breaker.
Charlie applied for his first patent on April 13, 1959. No go. His second application, abandoned like the first, came on August 31, 1962. It wasn't until his third patent attempt, now trimmed down to "Motorcycle having two driven wheels", filed August 20, 1963, that Charlie would finally get his patent. By the date of the third filing, the bike was in full-fledged production but, yet it would be August 23, 1966 before the patent would be granted.
Many myths follow the story of who solved the Trail-Breaker's original steering problem. Well, I'm here to tell you that contrary to popular belief, it was Fehn who solved the steering problem (inherent in a two-wheel-drive motorcycle) by developing a driveline over-ride mechanism. He developed the over-ride clutch and incorporated it into the original patent but, the early mechanism used a complex ball-bearing-on-ramp system (a bit Rube Goldbergesque), so it was simplified in 1962 to a one-way spring-on-collar device, which is basically the same over-ride spring assembly that is still in production today. This one-way clutch allows the front wheel to travel faster than the back wheel, but not vice-versa. This is what allows you to turn corners without having bike and body driven to the ground, the result of having both wheels turning the same speed when the front wheel needs to travel farther in a corner. Another of his patents was the hollow aluminum wheel, which holds 4.5 gallons of liquid ballast or fuel. Conversely, with the wheels empty, the bike can be thrown into a body of water and will float just fine enabling you to date Kelly Mathewson at the camp across the pond. Two ingenious ideas, one great motorcycle, the Trail-Breaker.
