A long-lost invention that you can find in your RC cars
How did a lawn mower part end up being a crucial component of remote control cars? RC Cars Hobby will tell you the story of the ball differential, a part that your radio
control car certainly has; you'll find out who invented it and what it does.
The ball differential was first invented earlier than you might think. At the beginning of the 20th century, an American engineer designed such a differential as a possible lawn mower component. This original inventor even managed to secure a patent for his ball differential. But the design was never applied in practice: no ball differentials were produced, and the patent was soon forgotten. It would take another three-quarters of a century for the idea to be rediscovered.
In the early 1980s, Cecil Schumacher, founder of Schumacher Racing Products Limited and manufacturer of Schumacher RC cars, made a major contribution to the RC cars hobby by reinventing the ball differential-- all on his own, without knowledge of the earlier patent. It came as quite a surprise to him to find out that such a patent had already existed-- and expired!
Of course, because the patent was no longer valid, Schumacher could continue producing ball differentials and did so with remarkable success; Schumacher's invention was directly responsible for a vast array of championship-quality Schumacher RC cars. But his competition could legally make use of his design as well; virtually every manufacturer of RC cars and trucks saw the ball differential's advantage and incorporated the ball differential into its line of products.
So, what does a ball differential do? It's indispensable if you want your remote control car's wheels to rotate and for the remote controlled car engine's power to be transmitted to them. The name "differential" comes from this device's ability to get each of the wheels to rotate at a different speed from the others. This difference of speeds is vital for your remote control car to turn properly-- because each wheel's distance when going through the turn is different from every other wheel's.
Most life-sized automobiles use a geared differential - which has bevel gears that enable the engine's power to be transmitted to the wheels. The ball differential uses ball bearings instead; the ball bearings are positioned between two plates and rotate there. The ball bearings are tiny-- about two millimeters in a diameter-- and can easily fit inside the holes of the differential's main gear or pulley. The ball differential's compact size renders it a great fit with many smaller RC cars.
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