Patent ID: 6997090

Claim:
A saw comprising: a blade configured to move to cut a work piece, where the blade includes a cutting edge; a motor adapted to move the blade; a detection system adapted to detect contact between a person and the blade while the blade is moving and to distinguish that contact from contact between green wood and the blade by imparting a signal to the blade and monitoring that signal for a predetermined rate of change indicative of contact with a person; and a replaceable brake cartridge adapted to stop the blade when the detection system detects contact between a person and the blade, the brake cartridge including: a housing; a brake pawl pivotally connected with the housing and having a blade-contact surface; a biasing mechanism at least partially enclosed by the housing and adapted to urge the brake pawl to pivot relative to the housing; and a release mechanism at least partially enclosed by the housing and adapted to release the brake pawl to pivot relative to the housing under the urging of the biasing mechanism when the detection system detects contact between a person and the blade; where the brake cartridge is positioned in the saw so that the blade-contact surface can pivot into contact with the cutting edge of the blade to stop the blade.