How does a flesh-sensing table saw stop the blade?

[munky99999]

http://www.muchosucko.com/video-amazingtablesaw.html

It is a table saw that does not cut off your finger, could someone explain this?

 

[enigma]

I dunno... it looks like a doctored video to me. One frame has the saw, the next it's completely gone.

 

[munky99999]

it retracts, watch it in slow motion, if u can.

 

[dduardo]

I have to agree that it is doctored. Here is why:

1. The website you found the video doesn't look very credible
2. How does the blade know the difference between your finger and a piece of wood? You really can't tell.
3. I did a google search and couldn't find anything supporting this video.

 

[munky99999]

well the site puts everything that could be funny to someone, there is a good chance that it was doctored, but I thought that they would have someone researching that very thing, cause that tool would be the standard if made.

 

[Ivan Seeking]

My firewall is blocking the video, and I really don't want to disable it, but I think I know of this technology...in fact I know the company that developed it. I am also under a legal obligation not to say how it works. I can only say that it is possible to tell a finger from a piece of wood. It is a very clever idea. This particular site may or may not be showing the same thing that I know about, but it sure sounds like it. The demonstration sounds identical to the one used by my customer.

 

[enigma]

Can you at least say what the company's name is, Ivan?

 

[munky99999]

my hypothesis(haha) is that there is some sort of resistance a piece of wood would give, and obviously a finger with a less strong texture, would give a different resistance.

But I really don't think that is very practical.

 

[Ivan Seeking]

Can you at least say what the company's name is, Ivan?

Since I don't know the politics of this I shouldn't say anything specific. I can assure you though that if I said how it worked, you would all immediately understand. No magic here.

 

[Ivan Seeking]

You will see this technology applied more generally soon. I assume that the demand for secrecy was due to patent issues. Of course, sometimes these things just get silly. For a long time I couldn't use the word "Wahoos" either - a new General Mills product - but this was supposed to be a really big deal.

 

[Integral]

http://www.sawstop.com/video.htm is the source of the video. A little more respectable. Ivan if this is not the same as your source then there has been some industrial espionage going on.

Oh yeah. It imposes a AC signal on the blade, flesh has much different electrical properties then wood, when the changes a mechanical brake is engaged stopping the blade in less then 5ms. They have similar systems for band saws.

Does this work with metal or only wood?

(A table saw cuts Al plate very nicely.)

 

[Ivan Seeking]

Oh good. I was uncomfortable making a statement that I'm not allowed to back up.

The system that I know about should work with metal or wood.

There may be several approaches to this problem...