I have been meaning to post about SawStop table saws ever since I started this blog last month. Anyone who has or nearly injured a hand on a table saw will be very interested in SawStop. This innovative saw uses an electrical current in the blade to detect flesh contact. From the site:
The SawStop safety system includes an electronic detection system that detects when a person contacts the blade. The system induces an electrical signal onto the blade and then monitors that signal for changes. The human body has a relatively large inherent electrical capacitance and conductivity which cause the signal to drop when a person contacts the blade. Wood has a relatively small inherent capacitance and conductivity and does not cause the signal to drop.
A fast-acting brake stops the blade when contact is detected. The brake includes a heavy-duty spring to push a block of aluminum, called a brake pawl, into the teeth of the blade to stop the blade from spinning. The spring is held in compression by a fuse wire until contact is detected. When contact is detected, the system sends a surge of electricity through the fuse wire to burn the wire and release the spring. The spring pushes the brake pawl into the teeth of the spinning blade, and the teeth cut into the aluminum and bind, thereby stopping the blade. All this happens in about 3–5 milliseconds, or 1/200th of a second. At the same time, the angular momentum of the blade causes the blade to retract below the table and the power to the motor is shut off.
Basically, this bad boy detects contact with a finger, retracts and stops the blade so fast that a potential amputation injury becomes a far less serious nick. Whether you are a woodworker or not you can't miss the dramatic video demonstration on the site.
Apparently these saws are excellent for high school wood shops and cabinet shops saving severe injuries. Nice.
Technorati Tags: design, disability, Disabled Hands, injury, cabinet making, SawStop, shop class, table saw, woodworking
my only question is: how do they do quality assurance testing on these things?
"OK: Bob's done for the day.. start giving Bill those vodka shots..." :-)
Posted by: Neil McDevitt | February 01, 2006 at 12:43 PM
These are indeed very neat devices bit expensive to run out and replace my unisaw just yet. The other thing worth mentioning is that your blade is toast after the aluminum welds on to it.
Posted by: Steve Shaffer | February 18, 2006 at 09:26 PM