The magic of the rotating shaft

Discovering the mechanical magic through a three-inch gap

A short text in english. Thanks to Rachel Price, who helped me correcting it.

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As far back as I can remember, I’ve been fascinated by vehicles, especially by trucks. I grew up on a horse farm, and my father had one of those old Ford trucks with a rounded metal body. It was a diesel, of course, and so the motor roared very loudly.

My sister and I, we used to hop in the bed of the truck, often with one or two of our dogs, and our father would drive us along the country road like this. We lived so deep in the mountains, I don’t remember ever worrying about the police. We enjoyed this ride in the trunk, feeling the breath of fresh air on our faces, seeing the landscape slipping and blurring away. For us, it was an adventure. All the more so since the dogs were always be tempted to jump out while the truck was moving! When we saw them get excited, we would try to hold them back. But sometimes they would jump anyway, even though the truck was going very fast! So we would see them falling and rolling on the dirt road, and then getting back up on their feet (they were tough animals!) and staring at the truck, at us slowly disappearing over the horizon.

As for us, we liked to stand just behind the cab, holding on to the roof so that we could really face the wind and feel the speed. But there was a narrow space of three or four inches between the bed and the cab. Leaning over that space, not only would I see the ground flowing past under my feet at a frightening rate, but I would also notice a strange piece of machinery. I didn’t know the name at that time, but I learned long later that it’s called a “transmission shaft”. It is used to transfer the energy from the motor to the back wheels. What I saw was a joint, a kind of gimbal, turning mechanically, invariably under my eyes, while the ground below kept on slipping and blurring. For me, this image was very intriguing. In it was summarized the whole magic of machinery and vehicles. One thing, the shaft, the mechanical piece, rotates, and that very movement makes the ground unfurl. A rotative movement is transformed into a linear movement : that is the mechanical magic I discovered riding in the back of my father’s truck on the Red Pine country road. In that three-inch gap between the bed and the cab, the mystery was revealed to me, to my five or six-year-old eyes.