Date: May 23, 2016
`
`Case: Certain Table Saws Incorporating Active Injury Mitigation
`Technology & Components Thereof
`
`Ace-Federal Reporters, Inc.
`Phone: 202-347-3700
`Fax: 202-737-3638
`Email: info@acefederal.com
`Internet: www.acefederal.com
`
`
`
`SD3 Exhibit 2003 – Page 1
`
`PUBLIC VERSION
`
`

`
`UNITED STATES OF AMERICA
`BEFORE THE
`INTERNATIONAL TRADE COMMISSION
`
`- - - - - - - - - - - - - - - - - -x
`IN THE MATTER OF:
`:
`CERTAIN TABLE SAWS INCORPORATING
`:
`ACTIVE INJURY MITIGATION TECHNOLOGY:
`AND COMPONENTS THEREOF
`:
`- - - - - - - - - - - - - - - - - -x
`
`Investigation Number
`337-TA-965
`
`HEARING, VOLUME 2
`
`Monday, May 23, 2016
`Courtroom B
`U.S. International Trade
`Commission
`500 E Street SW
`Washington, DC
`
`The Hearing commenced, pursuant to notice of the Judge, at
`8:51 a.m., before the Honorable Thomas B. Pender,
`Administrative Law Judge for the United States
`International Trade Commission.
`
`1
`
`2
`
`3
`
`4 5
`
`6
`
`7
`
`8
`
`9
`
`10
`
`11
`
`12
`
`13
`
`14
`
`15
`
`16
`
`17
`
`18
`
`19
`
`20
`
`21
`
`22
`
`23
`
`24
`
`25
`
`202-347-3700
`
`Ace-Federal Reporters, Inc.
`
`Page 140
`
`202-737-3638
`
`
`
`SD3 Exhibit 2003 – Page 2
`
`PUBLIC VERSION
`
`

`
`Page 173
`
`Page 174
`
`14
`15
`16
`17
`18
`19
`20
`21
`22
`23
`24
`25
`
`STEPHEN GASS
`was called as a witness and, having first been duly sworn,
`was examined and testified as follows:
`JUDGE PENDER: Please be seated.
`And one of the challenges that we have is that,
`so we can actually hear witnesses. So when you turn your
`head and all that stuff, just be aware that we can lose
`sight of -- I may lose my ability to hear you as well as
`I'd like to, okay?
`THE WITNESS: Thank you.
`DIRECT EXAMINATION
`BY MR. BRINKMAN:
`
`Page 175
`Q Good morning, Dr. Gass. Can you please state
`your name for the record.
`A Good morning. Stephen Gass.
`Q Where do you live?
`A In Westlin, Oregon.
`Q Where do you work?
`A At SawStop.
`Q What's your current job title at SawStop?
`A President.
`Q And if you'd briefly describe your academic
`background since college.
`A Well, I started my undergraduate studies at
`Oregon State University. I got a bachelor's in physics. I
`then went to the University of California at San Diego,
`where I got my doctorate in physics.
`I then went to the University of California at
`Berkeley for law school.
`Q Can you similarly describe your professional
`background starting in college.
`A Well, I worked for a year as a programmer
`between graduate school and law school, while I was
`waiting -- kind of having finished my PhD. And then after
`law school, I started as a patent attorney with a patent
`firm in Portland, Oregon.
`Q When did you develop an interest in woodworking?
`
`Page 176
`A I've done woodworking since I was a small child.
`My first accident on a woodworking -- piece of woodworking
`equipment was a jointer when I was 4 years old in my dad's
`shop. I was lucky to keep my thumb. So I've done it my
`whole life.
`Q Have you always been interested in safety with
`woodworking machines?
`A Well, you know, you get maybe some sense of my
`safety consciousness. I'm like the average woodworker.
`You know, I don't always wear safety glasses, I don't
`always wear earplugs when I should. I'd never seen a guard
`on a table saw until I started SawStop.
`So I'm not the sort of safety stickler type of
`person. I really have become much more aware of safety as
`a result of what I've been doing with SawStop.
`JUDGE PENDER: You just said that you've never
`saw a guard on a table saw until you went to work at
`SawStop. For the record, explain why people who run table
`saws don't put guards on them.
`THE WITNESS: Well, you can look at it at a
`number of different levels. The guards that existed
`historically were so badly designed that I think they were
`essentially unusable. I believe that they were present
`largely to protect the manufacturers against product
`liability rather than protecting customers against
`
`1
`2
`3
`4
`5
`6
`7
`8
`9
`10
`11
`12
`13
`14
`15
`16
`17
`18
`19
`20
`21
`22
`23
`24
`25
`
`1
`2
`3
`4
`5
`6
`7
`8
`9
`10
`11
`12
`13
`14
`15
`16
`17
`18
`19
`20
`21
`22
`23
`24
`25
`
`202-347-3700
`
`Ace-Federal Reporters, Inc.
`
`10 (Pages 173 to 176)
`202-737-3638
`
`
`
`SD3 Exhibit 2003 – Page 3
`
`PUBLIC VERSION
`
`

`
`Page 177
`
`injuries.
`But the -- that said, physically, the guards
`were flimsy, they were difficult to take on and off, they
`were difficult to realign if you did take them off. So
`there was a huge disincentive for the customer to actually
`use it.
`
`It also blocks your ability to see what you're
`doing when you're actually doing the cut. It just gets in
`the way. It can prevent the fence from getting up close to
`the blade if you're doing a narrow cut. There are a whole
`sort of raft of reasons.
`But the end result of that is that, you know,
`they're just very, very rarely used historically. When we
`designed our saws, we tried -- I tried to come up with a
`guard that was -- a number of different guards, actually,
`that gave users a reason to use the guard. So -- but that
`was, you know, not historically the case.
`BY MR. BRINKMAN:
`Q And I realized while you were speaking that I
`hadn't gotten the direct binders passed out, so Andrew is
`doing that right now. I think my next question involves an
`exhibit. So let's do that.
`Actually, Curt, you can put up, while we're
`doing that, Exhibit CX-254. I want to make sure everybody
`gets a copy before we go further.
`
`Page 178
`Dr. Gass, just as a matter of convenience, I'll
`have Curt put on the display in front of you whatever I'm
`asking you about exhibitwise. So feel free to look in the
`binders and find the exhibit if you feel you need to. But
`otherwise, if you don't, we can just -- you can take a look
`at the screen.
`Do you know what CX-254 is? What does it show?
`A Well, it's the cover of a -- what I see here is
`the cover of the Hazard Screening Report on power tools and
`workshop equipment from the Consumer Product Safety
`Commission. They track injuries on a variety of -- well,
`almost all consumer products. And one of the areas that
`they have particularly focused on has been power tools.
`So they prepared this report in June of 2003,
`where they essentially tabulated the costs, the economic
`costs to society, of accidents on table saws.
`Q If you'll turn into that to page CX-254 at 11.
`A I'm sorry, but this one is numbered sort of
`sequentially. I guess I can figure it out.
`JUDGE PENDER: Bottom right-hand corner, Doctor.
`THE WITNESS: The tabs here are not numbered by
`the exhibit number, so I'll have to find the corresponding
`number.
`BY MR. BRINKMAN:
`Q 26, I'm told by very helpful Mr. Hannemann.
`
`1
`2
`3
`4
`5
`6
`7
`8
`9
`10
`11
`12
`13
`14
`15
`16
`17
`18
`19
`20
`21
`22
`23
`24
`25
`
`1
`2
`3
`4
`5
`6
`7
`8
`9
`10
`11
`12
`13
`14
`15
`16
`17
`18
`19
`20
`21
`22
`23
`24
`25
`
`Page 179
`JUDGE PENDER: Right, I notice that is true for
`both sides. Tell everybody what tab it is and then they
`will find it, okay?
`BY MR. BRINKMAN:
`Q Have you got to that page yet, sir?
`A Yeah, so on page 11 of this exhibit, there is a
`table, you've got it up, and you can see one of the entries
`on this is bench or table saws.
`So this is basically the total costs for
`accidents, societal -- their estimate of the total costs to
`society from accidents on table saws.
`And somewhat amazingly, if you look here, it's
`actually close to $2 billion a year that they estimate the
`cost of accidents. And that's on -- total retail market is
`a small fraction of that, probably 2 to 400 million. So
`table saws as a product category are doing somewhere in the
`neighborhood of five to 10 times their purchase price in
`economic harm from the accidents that happen on them.
`Q If you would turn in your binder to tab 35, it's
`CX-513.
`A Okay.
`Q Tell me what that is.
`A This is a -- basically, it's the notes from a
`meeting of the Consumer Product Safety Commission, one of
`the engineers, Caroleene Paul from the Consumer Product
`
`Page 180
`Safety Commission, with members of the PTI, to talk about
`what could be done with regard to table saw injuries, and
`in particular, this spells out the industry position with
`what they thought about what could be done.
`Q And what's the date of that document?
`A This is December 29, 1999. Well, the date of
`the meeting was December 8, 1999.
`JUDGE PENDER: Out of curiosity, Doctor, do you
`recall how you got hold of this? I mean, did you --
`THE WITNESS: This is actually a public record
`from the CPSC. I'm not sure where we first got it. I
`don't know if the CPSC provided us a copy or -- I've
`testified in the past, as you might be aware, in product
`liability cases. And I think this -- we might have seen
`it, so those attorneys may have located the document.
`JUDGE PENDER: So this is in your irony file.
`THE WITNESS: That's a good way to put it, your
`Honor, thank you.
`So I think the interesting part about this is
`actually on the next page, where the industry kind of
`expresses its opinion. In particular, they say that "PTI
`believes the current spreader guard is the best possible
`guard for most through cuts. Education is the only way to
`affect the injury patterns seen. Education, not
`redesigning the guard, is needed to convince operators to
`
`1
`2
`3
`4
`5
`6
`7
`8
`9
`10
`11
`12
`13
`14
`15
`16
`17
`18
`19
`20
`21
`22
`23
`24
`25
`
`1
`2
`3
`4
`5
`6
`7
`8
`9
`10
`11
`12
`13
`14
`15
`16
`17
`18
`19
`20
`21
`22
`23
`24
`25
`
`202-347-3700
`
`Ace-Federal Reporters, Inc.
`
`11 (Pages 177 to 180)
`202-737-3638
`
`
`
`SD3 Exhibit 2003 – Page 4
`
`PUBLIC VERSION
`
`

`
`Page 181
`
`use the blade guard."
`So that was sort of the industry response to the
`CPSC's concern that table saws were causing a huge number
`of accidents every year.
`BY MR. BRINKMAN:
`Q What is the PTI?
`A The PTI is the Power Tool Institute. It's
`essentially the industry consortium group that represents
`the interests of the industry. Bosch is a member, Black &
`Decker, Ryobi, all the major power tool manufacturers.
`Q Can you explain what active injury mitigation
`means.
`A Sure. It's essentially active as opposed to
`passive. A guard is really a passive measure. It's
`something that blocks you from getting close to the blade,
`but it doesn't do anything if you get past it or you get
`close to the blade. It's just there passively.
`An active system takes some action. It responds
`in some way to the accident. So sort of the difference
`between a seat belt and an air bag. A seat belt is there
`if you put it on, but when the accident happens, it doesn't
`do anything extra.
`Whereas an air bag, when it senses the accident,
`it changes the environment in some way to try and protect
`you.
`
`Page 182
`Q When did you invent what we'll call SawStop
`technology?
`A In late 1999.
`Q I'm going to have you walk us through your
`inventive process as you did through the technology
`tutorial, but we'll do it in pieces.
`Can you put up CDX-1, please.
`First, what are we looking at here?
`A This is actually my shop, barn. I built this
`barn myself. I drove every nail and cut every board on it.
`It took me about three years of working. I'd get up at
`5:00 in the morning and go out to work before I went to
`work as a patent attorney and come home and work in the
`evening until dark. It was sort of my labor of love to
`build a shop to do woodworking in.
`I had dust collection vents run under the
`concrete in the floor. So it was all -- all my dust
`collection was hidden. The power cords, I had conduits in
`the floor next to the dust collection --
`JUDGE PENDER: So you're an early disciple of
`Bill Pentz, then.
`THE WITNESS: Yes, I had my own Cyclone dust
`collector, 7-1/2 horsepower, as a matter of fact. So I had
`three phase power in there.
`JUDGE PENDER: Wow.
`
`1
`2
`3
`4
`5
`6
`7
`8
`9
`10
`11
`12
`13
`14
`15
`16
`17
`18
`19
`20
`21
`22
`23
`24
`25
`
`1
`2
`3
`4
`5
`6
`7
`8
`9
`10
`11
`12
`13
`14
`15
`16
`17
`18
`19
`20
`21
`22
`23
`24
`25
`
`Page 183
`THE WITNESS: It was an amazing shop.
`BY MR. BRINKMAN:
`Q All that is wood shop?
`A The downstairs is all wood shop. The upstairs
`was empty, sort of a play area for the kids. Initially
`when we started SawStop, we actually ended up kind of
`putting some carpet in upstairs and putting a bathroom in,
`and then we used it as sort of SawStop world headquarters
`until we started selling saws. The first container of
`saws, actually, we unloaded in the driveway there. But
`that quickly became unworkable.
`Q What problem were you trying to solve in that
`barn when you invented SawStop technology?
`A Well, in some sense, it was really -- I was
`trying to answer a question. You know, I'm a curious
`person, I have ideas, and I thought, you know, can I stop
`that blade fast enough if I ran my hand into it that I
`wouldn't get a serious injury.
`I obviously knew about table saw accidents. I'd
`had two people I knew who had cut three fingers off, each
`on saws. It's the sort of thing that anybody who does
`woodworking is aware of the hazard. But it's sort of what
`you live with. You're doing something that has certain
`hazards.
`But I was -- fundamentally the idea kind of came
`
`Page 184
`to me and I was trying to answer the question, could I do
`this. And so that's where I started was really with that
`question.
`Q What part of the problem did you work on first?
`A Well, I think -- I think the first thing I
`thought about was what -- how fast would I have to stop the
`blade? If I didn't do anything until I contacted the
`blade, how much time would I have to stop the blade?
`That really comes down to kind of a question of,
`as I thought to myself, two things. How fast is the hand
`going to be going? And as I said, I knew people who had
`had accidents, and in both those cases actually, they
`simply pushed their fingers -- they had their fingers in
`the wrong place on the material and pushed them through the
`blade without flinching. That's fairly typical, given
`human reaction time, that you don't flinch even in the time
`a blade goes through three fingers.
`So I thought, well, that's -- there was an
`accident that I was familiar with, so I thought -- how fast
`would they be going under those circumstances? I thought,
`as I'm feeding wood, gosh, you know, what would be a fairly
`high but not unreasonable speed?
`And I kind of did this a few times and thought
`probably about a foot per second would be about as fast as
`you would feed wood. And I thought, okay, and how much
`
`1
`2
`3
`4
`5
`6
`7
`8
`9
`10
`11
`12
`13
`14
`15
`16
`17
`18
`19
`20
`21
`22
`23
`24
`25
`
`1
`2
`3
`4
`5
`6
`7
`8
`9
`10
`11
`12
`13
`14
`15
`16
`17
`18
`19
`20
`21
`22
`23
`24
`25
`
`202-347-3700
`
`Ace-Federal Reporters, Inc.
`
`12 (Pages 181 to 184)
`202-737-3638
`
`
`
`SD3 Exhibit 2003 – Page 5
`
`PUBLIC VERSION
`
`

`
`Page 185
`injury -- what kind of a cut would result in a system like
`this still being viable commercially if you had an accident
`of a foot per second.
`When you figure that out, an 8th of an inch at a
`foot per second, an 8th of an inch is about 100th of a
`foot, 1/96th of a foot. So you have about 1/100 of a foot
`when you move in about 1/100 of a second at a foot per
`second.
`So I figured I probably have about 100th of a
`second of 10 milliseconds, 10/1000ths of a second, to do
`something to protect the user.
`First thing I thought of was stopping the blade.
`And so I then, having sort of concluded that I had about 10
`milliseconds to do it, then I had to kind of figure out
`could -- is that within the realm of physical possibility?
`Because it's -- you know, when you get down to
`those kinds of time scales, you just don't have experience
`as a human with that, so you can't I don't think accurately
`intuit what the response speeds and sort of the forces
`involved would be.
`So I did some calculations. I actually weighed
`a saw blade, calculated the angular momentum of that, the
`inertia and angular momentum spinning at 4000 RPM, and then
`did a calculation of how much torque would it take, or I
`did it in terms of the force applied at the perimeter of
`
`Page 186
`the blade, that's the most favorable place to put it to
`stop.
`
`So I calculated that, and it was on the order of
`1000 pounds. And I thought, shoot, I bet I could figure
`out how to apply a 1000-pound braking force to stop that
`blade.
`
`So that seemed pretty promising.
`Q What was the next part of the problem that you
`addressed?
`A Well, having decided that it was probably doable
`physically to stop the blade, then I had to come up with,
`well, okay, how do I know when to do that? How do I tell
`the difference between a person and the wood? And, you
`know, sort of being a physicist, I think of these things
`kind of in terms of fundamental principles, and what's
`different about a person and a piece of wood.
`And so you can -- I thought about, like, an
`ultrasonic system that would -- where you might be able to
`put a vibration on the blade, and maybe the finger is soft
`and the wood is hard, so maybe the wood would not absorb
`the vibration and the finger would.
`I thought about an optical system to look for
`blood on the teeth as it came under. And I thought about
`proximity detection, like using the blade like an antenna.
`The advantage there is you potentially could detect the
`
`1
`
`2
`
`3
`
`4
`
`5
`
`6
`
`7
`
`8
`
`9
`
`10
`
`11
`
`12
`
`13
`
`14
`
`15
`
`16
`
`17
`
`18
`
`19
`
`20
`
`21
`
`22
`
`23
`
`24
`
`25
`
`1
`2
`3
`4
`5
`6
`7
`8
`9
`10
`11
`12
`13
`14
`15
`16
`17
`18
`19
`20
`21
`22
`23
`24
`25
`
`Page 187
`contact -- or the dangerous proximity before you actually
`contacted the blade, which would be advantageous.
`Unfortunately, it's -- while you can make a
`system like that, and people have, it's very difficult to
`make that robust in terms of not going off when you don't
`want it to and always going off when you do.
`So I ultimately came up with this using the
`blade as a sensor with a contact detection, sort of like a
`touch lamp.
`So you -- the human body, because it's salty and
`wet, is a good conductor. And wood, even if it's wet, is
`not salty, unless it's drift wood. So I thought you might
`be able to tell the difference that way.
`So I actually built a little circuit, took a saw
`blade and laid it on my bench. I was -- I did hobby
`electronics, so I had an oscilloscope actually in my shop
`from my undergraduate days actually. I'd been doing it a
`long time.
`So I built a little circuit that I put a couple
`of pieces of printed circuit board -- I had some bare
`printed circuit board, which is a copper foil over a
`fiberglass board, and I laid that on the bench, took a
`piece of it and laid it on the bench, and laid the saw
`blade on top of it so it was separated from the saw blade
`by the fiberglass.
`
`Page 188
`And I applied an oscillating signal to that, and
`I could hook up the oscilloscope to the -- to the blade and
`see that signal on the blade.
`Then if I touched it with my hand, I could see
`that signal drop, so I could see a change on the
`oscilloscope of that signal.
`And I thought, well, that's good. I can at
`least sense me. Now what about wood?
`So I looked around, and on the bench I had a
`little piece of oak probably about this big that I grabbed
`and took it and set it down on there. And the signal
`didn't change. And I thought okay, that's good. What if
`it's a little bit wet?
`So I literally licked it with my tongue, stuck
`it back on there, and still no signal change.
`And then I -- what if it's really wet, so I went
`over and actually ran it under the faucet, brought it back
`and stuck it on there, and sure enough, still no signal
`change.
`At that point, I was kind of excited, because I
`had done everything I thought -- I had tested the things I
`thought led me to believe there was a high probability it
`would actually be workable.
`Q So you've investigated the force required to
`stop a blade and sensing human contact. How did you put
`
`1
`2
`3
`4
`5
`6
`7
`8
`9
`10
`11
`12
`13
`14
`15
`16
`17
`18
`19
`20
`21
`22
`23
`24
`25
`
`1
`2
`3
`4
`5
`6
`7
`8
`9
`10
`11
`12
`13
`14
`15
`16
`17
`18
`19
`20
`21
`22
`23
`24
`25
`
`202-347-3700
`
`Ace-Federal Reporters, Inc.
`
`13 (Pages 185 to 188)
`202-737-3638
`
`
`
`SD3 Exhibit 2003 – Page 6
`
`PUBLIC VERSION
`
`

`
`Page 189
`
`them together?
`A Well, the next thing was to sort of build a
`prototype, see if I could actually make it work. So I
`looked in the classified ads. This was pre-Craigslist.
`And I bought a used Craftsman contractor's table saw out of
`the paper for a couple hundred dollars.
`I brought it home and sort of took the case off
`of it and looked at it, turned it upside down, because the
`trendings are actually mounted to the table so you can take
`the cabinet off and so it's still there and works upside
`down.
`
`It has kind of a big cast-iron plate in the
`middle and then the arbor is mounted on an arbor block that
`kind of swings up and down next to it.
`I thought what's a good way to stop the blade?
`And I thought if I -- I thought I could probably make a
`brake that would run into the teeth and sort of if I
`pivoted it right, would jam. It would sort of self-lock
`once it hit the teeth of the saw blade.
`So I drilled a hole in the cast-iron and tapped
`it out and put a bolt in there. And I cut a little piece
`of oak in sort of a little wedge shape and drilled a hole
`in one end of it to make a pivot.
`Then I would -- I spun up the motor and I took a
`screwdriver and kind of flipped it into the blade so it
`
`Page 190
`made contact, and sure enough it jammed very quickly and
`stopped the blade.
`And because the -- I didn't have a high-speed
`camera or anything, so I -- but you could actually see the
`track of the wood, you know, it left -- it filled the teeth
`essentially with wood while it was stopping.
`So you had about a third of the blade where the
`teeth were all jammed full of wood. So I knew or I could
`calculate from that, knowing the speed of the blade, that
`it was stopping in probably, I think it was, about 7
`milliseconds at that point.
`Q How long did it take you to complete your first
`prototype?
`A I think it was about a month from kind of start
`to finish. Once I'd figured out -- you know, I had the
`brake there, the next piece of that that I had to do was
`the sort of how to actuate it.
`And that -- because the first thing that might
`come to mind for an electrical actuator would be a
`solenoid. That's far and away the most common
`electromechanical actuator. You just -- you know, it's a
`magnet with a piston in it and it pushes.
`But when you look at the speeds on those, for
`this particular application, it was really, I thought, too
`slow and not strong enough to be sort of a commercially
`
`1
`2
`3
`4
`5
`6
`7
`8
`9
`10
`11
`12
`13
`14
`15
`16
`17
`18
`19
`20
`21
`22
`23
`24
`25
`
`1
`2
`3
`4
`5
`6
`7
`8
`9
`10
`11
`12
`13
`14
`15
`16
`17
`18
`19
`20
`21
`22
`23
`24
`25
`
`Page 191
`viable solution, at least in this context, with a contact
`detection system.
`So I started thinking, well, what else is --
`what else is there that's an electrically operated or
`initiated actuator?
`And, of course, that's high speed and higher
`force. And the next thing that came to mind was the
`explosive, like a little squib, because you could -- those
`clearly are fast and you can put a lot of force. So I
`thought that that was a potential option.
`But I'm a guy working in my shop, I don't have
`explosives, at the time anyway. And so I felt, well, what
`can I do with what I've got?
`So I came up with reusing a spring with a small
`mechanical fuse wire that gets burned with a surge of
`current, melts it basically. Because I thought I can
`supply a lot of current very quickly, so I can dump a lot
`of energy into that fuse wire, and I think I can heat it
`very quickly.
`And the spring supplies a lot of force. So as
`long as I can release it, I thought I could make that
`happen quickly.
`So I built one, I used actually the nose gear
`from one of my radio-controlled airplanes, and a little
`strand of actually a stainless -- you know, I had a
`
`Page 192
`stainless steel cable. And I sort of unwound a section of
`it and pulled one little strand out of it and hooked that
`up to run the current through it, and had a -- some power
`supply capacitors, big sort of soda-can-sized capacitors
`and a MOSFET switch to turn on.
`And then I could push the button and it would
`burn that and kick the brake over into the blade.
`Then I hooked up the -- essentially the same
`thing I had on the bench, I hooked up mounted to the -- I
`mounted those copper PC board plates next to the blade,
`very close to but not touching the blade, to create a
`capacitive coupling to the blade, one going in and then a
`second one to sense the signal coming back out.
`And used that, fed that back into a little --
`very simple little circuit that when the signal dropped,
`when you touched the blade and the signal dropped, would
`change the -- the op amp would change states, turn on the
`MOSFET, which would burn the fuse wire. And at that point,
`I basically could do the hot dog demonstration that kind of
`has become our standard.
`Q When did you file your first patent application?
`A I think it was at the beginning of October 1999.
`So right around the time I had finished up that first
`prototype.
`Q What were you thinking of doing with the
`
`1
`2
`3
`4
`5
`6
`7
`8
`9
`10
`11
`12
`13
`14
`15
`16
`17
`18
`19
`20
`21
`22
`23
`24
`25
`
`1
`
`2
`
`3
`
`4
`
`5
`
`6
`
`7
`
`8
`
`9
`
`10
`
`11
`
`12
`
`13
`
`14
`
`15
`
`16
`
`17
`
`18
`
`19
`
`20
`
`21
`
`22
`
`23
`
`24
`
`25
`
`202-347-3700
`
`Ace-Federal Reporters, Inc.
`
`14 (Pages 189 to 192)
`202-737-3638
`
`
`
`SD3 Exhibit 2003 – Page 7
`
`PUBLIC VERSION
`
`

`
`Page 193
`
`Page 195
`
`1
`2
`3
`4
`5
`6
`7
`8
`9
`10
`11
`12
`13
`14
`15
`16
`17
`18
`19
`20
`21
`22
`23
`24
`25
`
`1
`2
`3
`4
`5
`6
`7
`8
`9
`10
`11
`12
`13
`14
`15
`16
`17
`18
`19
`20
`21
`22
`23
`24
`25
`
`technology at that time?
`A Well, I had a good job and I figured that I
`would license the technology. I didn't have any interest
`in building saws. I wasn't -- I didn't know anything about
`it. And so I -- I had a Delta saw in my shop there, I grew
`up using my dad's Delta Unisaw from the time I could sort
`of see over the top of it.
`JUDGE PENDER: The point is Unisaw is the
`standard of the industry; right?
`THE WITNESS: It is, had been. They had been
`around for -- I think it was 1937 or 1939 that that saw
`first came out, and it really was the sort of what -- just
`as you put it, the standard.
`So I thought of them as the leading saw
`manufacturer, so I looked up Delta and found contact and
`contacted them, asked them if they would be interested, and
`ended up showing it to them.
`BY MR. BRINKMAN:
`Q What did you show them?
`A Well, I did a little video of the operation,
`sort of the hot dog video basically. Now, it was very
`crude. There were wires hanging out from underneath the
`saw because you had these big soda-can-sized capacitors and
`whatnot. Essentially I put a piece of hot dog on the wood,
`ran it into the blade and it stopped. And you just had a
`
`Page 194
`
`little nick on the hot dog.
`I also sent them a copy of the patent
`application for sort of a technical disclosure so they
`would know how the system actually worked, and it had all
`the schematics and all the details of the actual system.
`Q Did you give them those details under a
`nondisclosure agreement?
`A I did.
`Q And what did they tell you?
`A Well, a couple months went by, and in early
`2000, they finally got back to me and said that they had
`looked at it and that safety doesn't sell, so they weren't
`going to -- weren't going to pursue it.
`JUDGE PENDER: Do you have a letter that says
`safety doesn't sell?
`THE WITNESS: You know, they -- that was on the
`phone, but interestingly -- and maybe somewhat
`surprisingly -- there's a -- we have a -- there's a
`Washington Post article where Scott Box from Delta says
`exactly that, on -- to a reporter.
`I found it sort of stunning.
`You know, it's -- to me it was sort of
`interesting, because it -- if you talk about safety in
`terms of guards and the crappy guards that the industry
`offered, then yeah, I would agree with them, that kind of
`
`1
`2
`3
`4
`5
`6
`7
`8
`9
`10
`11
`12
`13
`14
`15
`16
`17
`18
`19
`20
`21
`22
`23
`24
`25
`
`1
`2
`3
`4
`5
`6
`7
`8
`9
`10
`11
`12
`13
`14
`15
`16
`17
`18
`19
`20
`21
`22
`23
`24
`25
`
`crappy safety doesn't sell.
`But as a woodworker, you know, this kind of
`safety I thought would sell, something that you don't even
`know is there, doesn't interfere with your work in any way,
`but if you run your hand into the blade saves you from a
`devastating injury, that safety I thought would sell, I
`believed as a woodworker.
`BY MR. BRINKMAN:
`Q After your rejection by Delta, what did you
`decide to do next?
`A Well, in between, we -- because I didn't hear
`from Delta, we had contacted a couple of other
`manufacturers, I think Jet and maybe Grizzly. But -- and
`they had sort of similar, showed some interest but didn't
`pursue it.
`And so I thought, this is -- this is crazy. If
`woodworkers knew about this, they would -- I thought there
`would be sort of a grassroots push, and they would ask for
`it and show the manufacturers that yes, they were
`interested in it.
`So I got a couple of my friends from work, three
`of my friends, actually all David by coincidence, thus the
`name SD3, Steve and three Davids, and we pooled our
`resources, money and time, and had three kind of more
`refined prototypes built that we could then take to a trade
`
`Page 196
`
`show and show people this technology.
`And because of some of the work we'd done as
`patent attorneys in the industry on a big industrial
`sander, we knew about the IWF show, the International
`Woodworking Fair in Atlanta, which is sort of the mecca if
`you're a woodworker, but it's the biggest show in the
`country, happens every other year. And it was coming up
`that following summer.
`And so we had these prototypes built and took
`them to the show to demonstrate and show people how it
`worked.
`MR. BRINKMAN: Let's take a look at a video,
`which is CPX-15.
`And I would ask the court reporter to please
`transcribe what we hear.
`(Video played as follows.)
`Hi, I'm Steve Gass, the inventor of the SawStop.
`The SawStop is a safety system to detect accidental contact
`between the blade and table saw and a person and stops the
`blade in just a few milliseconds before any serious injury
`can occur.
`We'll demonstrate the system on this Jet
`contractor saw that we've equipped with our safety system.
`In the first demonstration, I'll be cutting a piece of
`particle board and place a hot dog on top to simulate a
`
`202-347-3700
`
`Ace-Federal Reporters, Inc.
`
`15 (Pages 193 to 196)
`202-737-3638
`
`
`
`SD3 Exhibit 2003 – Page 8
`
`PUBLIC VERSION
`
`

`
`Page 197
`finger accidentally placed in the path of the blade. In
`the second demonstration, I'll touch the side of the blade
`with my finger. I'll explain how the system works. Let me
`show you.
`In this close-up, I want to show you how small
`the cut it in the hot dog. This time I'm going to
`demonstrate the system by touching the side of the blade
`with my finger.
`Now I'll explain to you how the system works.
`It basically relies on the differences in the electrical
`properties between a human body and wood.
`I think the best way to illustrate that is with
`an oscilloscope. This oscilloscope is connected up through
`the cable to the saw blade underneath. And the signal you
`see on the display is coming from this blade.
`You will notice that when I touch this blade
`with my hand, that the signal gets significantly smaller.
`And I compare that with doing the same thing
`with a piece of 3/4-inch plywood. You will notice if I
`bump that up against the blade, there's no significant
`change in the signal coming on the oscilloscope. Similarly
`with a piece of medium density fiberboard. Again, there's
`no significant change on the oscilloscope.
`Even with a piece of wet wood, which you might
`suspect would be more similar to a human body, there's
`
`Page 198
`still no significant change when you touch it against the
`blade.
`
`The system uses a standard blade, it hasn't been
`modified in any way. When a user touches the blade, the
`system triggers the brake within about 15 millionths of a
`second, and that then stops the blade in just a few
`milliseconds.
`(Video Stopped.)
`BY MR. BRINKMAN:
`Q Dr. Gass, why was the video prepared?
`A Well, this was a video we prepared to enter the
`Challengers Award competition in Atlanta at the IWF, they
`have an award they offer called the Challengers Award,
`competition, and it's for the most innovative new products
`each -- every other year.
`And we prepared this video as our -- part of our
`entry package for that competition.
`Q And for that prototype you prepared, prototypes,
`how did you set up detection?
`A Well, we had a capacitive coupling, just like
`the first one, it changed in the versions we took to the
`show. We -- rather than using a large plate, PC board next
`to the saw blade, we actually moved the capacitive coupling
`into the -- sort of between -- the area between the
`bearings, we took two brass tubes and put them in a plastic
`
`1
`2
`3
`4
`5
`6
`7
`8
`9
`10
`11
`12
`13
`14
`15
`16
`17
`18
`19
`20
`21
`22
`23
`24
`25
`
`1
`2
`3
`4
`5
`6
`7
`8
`9
`10
`11
`12
`13
`14
`15
`16
`17
`18
`19
`20
`21
`22
`23
`24
`25
`
`Page 199
`sleeve that fit in between the two bearings kind of
`concentric, very close to but not touching the outside
`surface of the bearing.
`That creates sort of a cylindrical parallel
`plate capacitor, but it's also dust-sealed so it's a more
`convenient location.
`So on that saw, on the prototypes we took to
`Atlanta, we used that capacitive coupling. But again it
`was the same sort of signal comes in on one capacitive
`coupling, goes to the blade and then is sensed by the
`second capacitive coupling.
`Q What alternative means of detection had you
`considered?
`A Well, as we -- I think I mentioned before,
`the -- you know, I thought about proximity detection, I
`thought