US Patent 7640837 Table saw with improved safety system

A table saw having an adjustable blade, a detection system to detect contact between a person and the blade, and a brake mechanism to engage and stop the blade upon detection of contact between the person and the blade is disclosed. The saw includes a brake positioning system that adjusts the position of the brake mechanism to maintain the brake mechanism in an operative position relative to the blade as the position of the blade is adjusted. The saw also may include a retraction system that urges the blade downward, away from a user, upon detection of contact between a person and the blade. The retraction system may include a releasable gear. The saw may be constructed so that the blade is adjustable up and down around a pivot point downstream of the blade relative to the feed direction.