Saw Shield

[rpd]

This looks like it could be an interesting alternative to Sawstop.
Can be retrofitted to table saws with riving knives, and to bandsaws. Doesn't damage the blades. No contact sensing.
https://www.getsawshield.com/

[RFGuy]

Very interesting. Glad to see someone has found a way to bring this to market to make more saws safer. Guess they found a way to get around the Sawstop patent. In watching the installation video it appears that it would be a very hard retrofit to make it work on a Mark V though unfortunately.

[edma194]

There's no explanation for exactly how it senses a sausage in the proximity of a saw blade, but I assume it's sensing capacitance.

The prices they show are at a 50% introductory discount, so it's pretty pricey stuff at regular prices. Still nice to have the option for other makes of saws besides Sawstop. Since it's using a brake on the blade there may be some way to integrate it into a new type of lower blade guard.

[JPG]

This grinch has difficulty with anything that uses capacitance as a proximity detector. Think Theremin(sp??)!!!

[BuckeyeDennis]

I smell a rat.

The videos show the blade stopping well before the sausage contacts the blade. I have a very difficult time believing that such a device would not violate SawStop’s patents, or that it could be installed on random saw models in an hour or two by the end user.

So I spent a few minutes checking out the Terms and Conditions posted on their website. After skimming through copious amounts of generally irrelevant boilerplate, I found the following gems in Section 24:

“Preorder Items are subject to a fifty (50) percent non-refundable deposit due at the time of the preorder purchase. Preorder Items can be canceled at any time prior to shipping. However, in the event of a cancellation, the fifty (50) percent non-refundable deposit shall be forfeited.”

“Due to the uncertain nature of Preorder Items, the Company makes no promise or guarantee that any Preorder Item will be manufactured or delivered, and the Company reserves the right to cancel an order for any Preorder Item at any time.”

Pre-orders are not being made through a reputable crowdfunding company such as KickStarter.

Perhaps our resident attorney could offer an opinion on this. Al?

[edma194]

The Sawstop patents begin to expire next year, but I don't know exactly what they have patented. Sawstop requires contact with skin to trigger the brake and retraction system, this one is triggered by proximity and only uses a brake.

[algale]

Dennis,

I've got not expertise in this area so my opinions are no better than anyone else's! Not giving advice here, but here are my non-professional musings as a woodworker:

1. I wish them nothing but success. Personally, however, I wouldn't ever put a non-refundable deposit down with a company with terms that seem to say, give us your money and maybe someday you will get a product. Whether you do or don't get a product, you don't get your money back. What???

2. I thought it was weird the blade stopped when the hot dog was still pretty far away from the blade. Their FAQ says their tech senses your finger when it is still 3/8 to 3/4 away from the blade but that can be adjusted. That suggests the sensing tech at work is very different from saw stop's in as much as I think saw stop uses a change in the electrical resistance of the blade that only occurs when something conductive (like your finger) touches the blade whereas this has some kind of sensor that doesn't require blade contact. My wild guess would be some kind of visual/infrared camera system.

3. But the blade brake tech itself may still be similar enough to saw stop's brake patent to violate the patent. Then again, maybe the fact that it doesn't destroy the blade suggests it really is different. Again, not my area of expertise.

4. They sure are skittish about showing their tech, which is frustrating. They have an "installation" video which show them attaching a mounting bracket that their device attaches to and nothing else. They never show the blade stopping device itself. They cut away and explain that they have no intellectual property protection so that if if they even show you their blade stopping device, there is a risk the big guys will copy it and put them out of business. They say something similar in their FAQ: "Due to intellectual property concerns, we are unable to provide details of our device at this time. We are pursuing both U.S. and international patents to protect our intellectual property. Until we have made greater progress in obtaining domestic and international patents, we cannot release detailed pictures or designs." It's hard for me to believe the blade stopping device can be so freaking simple that just seeing it would give away any patentable secret. But again, not my area of expertise.

[BuckeyeDennis]

“Mechatronics” is my own area of technical expertise, and I don’t believe that SawShield’s “tech” exists at all.

A spinning saw blade has an large amount of kinetic energy. To stop it in 5ms requires an burst of immense power absorbtion. Sawstop does this by ramming an engineered block of aluminum into the sawblade teeth. The aluminum is severely deformed, absorbing the energy. The resulting force on the aluminum block is huge, and no jury-rigged mounting bracket is likely to withstand it. Regardless of the brake-design details, stopping a blade in a similar time will require similar braking forces.

Even before braking, the proximity of flesh has to be detected. I’m familiar with many forms of non-confact sensing, none of which can rapidly discriminate flesh from other substances, especially in the presence of spinning metal and flying sawdust. Even SawStop’s contact-sensing technology can’t discriminate between flesh and wet lumber.

I’m no expert on SawStop patents, but I understand that they have a whole thicket of them. They were sufficient to stop Bosch from entering the US market, even though Bosch system had significant differences.

I could be wrong, but I’d lay long odds that the SawShield “tech” consists entirely of means for using the internet to separate woodworkers from their hard-earned money.

[algale]

I could be wrong, but I’d lay long odds that the SawShield “tech” consists entirely of means for using the internet to separate woodworkers from their hard-earned money.

lol

[RFGuy]

Yeah, I am sure SawStop, now TTS Tooltechnic Systems, has layered their patents such that as one expires there are additional ones that will protect the product well beyond the initial 20 years. Given how lawyer hungry SawStop has been in the past against competitors, I am willing to give this company a little more slack as I am sure they are concerned about this "Goliath" when they are a "David". Still, I acknowledge it could all be vaporware and I have experienced this from competitors in the past in my career. I know this doesn't mean much, but below is a pic that I grabbed from the video. They don't show the brake assembly, but this is the beefy mount for it and they show it being installed. It looks like 1/4" plate steel and it appears the brake assembly mounts under the sawblade so when it deploys it must thrust up into the blade. My guess is it is similar in design to SawStop but with a kinder, gentler material than aluminum to shove into your blade. Probably some type of resin material that can sustain sawblade speeds and yet be removed afterwards leaving a sawblade that is intact, though probably more than a little stressed and perhaps out of balance? Is it possible they manufactured this steel plate as part of a vaporware campaign? Sure, but you are talking about a pretty significant fraud to take customer money and never deliver the product. Remember John DeLorean? I haven't read the legalese, but honestly I don't see their campaign of taking preorders any different from Kickstarter, Indiegogo, etc. I mean I have had my own hits and misses on products I attempted to back on those two sites and sometimes you never get anything and your money is gone so it isn't like those sites protect the consumer either. In summary, I guess I am on the fence with it. I'd like them to succeed but I agree there is very little information to go on yet from this company.

While I love the technology, I have my concerns of how SawStop or SawShield works. It appears this product is using capacitive sensing to detect a finger, or meat product, near the blade. Sometimes we cut wet lumber and the fact that SawStop can't do that without risking ruining a blade is a real turn off to me...

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