Name: Circular Saw Kickback Killer (We used science to make tools safer) - Smarter Every Day 209
Uploaded: 2020-04-13T16:41:35.000Z
Duration: 10 min 41 s
Description: Thousands of YouTube videos with English-Chinese subtitles! Now you can learn to understand native speakers, expand your vocabulary, and improve your pronunciation...

- We are absolutely giddy because we've been working

- Well, I'll be like that's us hanging out

but we're working on this project for how long?

Chad's really good at software and we had an idea

What it does is it eliminates kickback from handsaws.

Chad, do you wanna explain what's going on here.

- Yeah, so you'll be cutting a piece of big

a big sheet of plywood and as you get down towards

the middle of it the pieces that you've already cut

start to bend towards each other and they'll pinch

the blade and when the blade gets pinched it becomes

kind of a wheel and these teeth, since they're coming

back towards you, catch in the wood and then the whole

If you've ever had it happen, maybe a couple drops

- You know exactly what I'm talking about.

We're gonna show how it works first with the high speed

camera and then we'll show you the fix we have

- [Chad] And it came out 'cause it got to the knot.

- You notice we have this chain and we've got

Will you show and make sure that the chains

- You need something for these safety glasses.

Because of the rotation direction of the blade,

the saw is lifted up out of the workpiece and then

that rotation, again, causes it to be propelled

Now obviously, if this were to really happen

you would want to release the trigger on the saw

and in this test we have it zip tied so we can actually

see what's happening but I found, personally,

that my body tenses up when I get startled

and I'm not so sure that I would have enough control

in the moment to make the decision to release the trigger.

Let's look at another run and I'll stand just outside

the danger zone and I'll pull focus on the camera lens

and we'll see if we can measure the human response times

- [Destin] Okay, in this run, look at the timer in the top

right of the screen that's counting from the moment

the saw starts rising up out of the wood.

You can see that the blade is fully released

and it's already headed up towards your gonadular region.

Assuming that you don't tense up, you would need

to respond by releasing the trigger well within

Once the blade is freed from the wood, there's no longer

any resistance and therefore the blade increases speed

Now that makes it even more dangerous and you can see

here when the blade falls back down and comes back

in contact with the wood, just imagine if that was flesh

and keep in mind here that this is a slow-mo video.

All of this that you're seeing here is happening

in just a tenth of a second after the blade

Obviously the ideal time to respond to a kickback

event is before the saw even leaves the wood.

The problem with all this is often times humans

Now what we're gonna do is show you what we've made.

It's a multi-axis detection system that can figure out

- [Destin] And basically dynamically break the motor.

Subtitles ListPlay Video

Circular Saw Kickback Killer (We used science to make tools safer) - Smarter Every Day 209

awesome

eliminate

trigger

description