Patent ID: 8065943

Claim:
A method of operating an up-cut chop saw, where the saw includes a work surface adapted to support a workplace, a spinnable blade configured to cut a workpiece on the work surface by moving from below the work surface to at least partially above the work surface, a motor to spin the blade, an actuation device to trigger the blade to move upward, a detection system adapted to detect a dangerous condition between a person and the blade by imparting a signal to the blade, where the signal has one or more associated characteristics, and monitoring at least one or more of the associated characteristics for a predetermined rate of change indicative of the dangerous condition, and a reaction system adapted to mitigate possible injury if the detection system detects the dangerous condition, where the saw includes a power switch to supply power to the detection system, the method comprising: turning on the switch to supply power at least to the detection system, whereupon the detection system then imparts the signal to the blade and starts monitoring at least one or more of the associated characteristics for the predetermined rate of change indicative of the dangerous condition; supplying power to the motor to spin the blade; placing a workpiece on the work surface; operating the actuation device to trigger the blade to start moving upward from below the work surface toward a position at least partially above the work surface; and if the predetermined rate of change is detected, then triggering the reaction system to mitigate possible injury.