Mar 4, 2017

[2.70] Seek and Geek #4: Alpine Ski Bindings

I went skiing with a buddy this past weekend, where by "skiing" I actually mean "learned to ski by falling down half the mountain."

It was super fun!
While falling, I got to truly appreciate my ski bindings and their wholly-mechanical release mechanisms that prevented me from taking awkward falls.

Ski bindings on skis

Ski bindings are interesting. They are simultaneously a safety release that detach the boot before you hurt your legs (skis are levers and your legs don't want the force multiplier) and a modulator for all the input forces you control the skis with.

Super-well thought out mechanisms that consider biomechanics of falling
The release-trigger tension, called the DIN setting, is calculated by a combination of skier weight, height, ability, age, and foot length. The front and back bindings for each ski are set separately and could be different DIN settings, but usually are the same value.

The rear binding has two especially interesting features. The first is a spring-loaded snow brake. When the boot heel is securely clamped in the binding, the heel keeps this snow brake folded up. But the moment heel pressure is released, the brake arms pop out and dig into the snow. So now, your skis won't fly down the slope without you! Additionally, the brakes raise the slippery surface of the skis off the snow - very helpful for when you're trying to reattach your boot while on a slope.
All ski bindings come with a safety brake to prevent the ski from sliding away
The second fun feature of the rear binding is that the entire thing has a spring and can slide forward and back along the ski. The ski is a long, elastic body that bends to absorb forces going down the slope... but the boot doesn't change shape with it. Therefore, as the ski bends the rear binding slides forward and back to accommodate the deformation of the ski without compromising clamping pressure on the boot heel.

Video illustrating preloaded rear binding keeping boot in place

1 comment:

  1. ski brakes are as big a thing as the bindings. we used to have "safety straps" ugh