Abstract: Power tools including electronic safety mechanisms with supervisory circuits. The power tools include a motor configured to generate a motive force, an implement holder, and an electronic safety mechanism. The implement holder is configured to receive the motive force from the motor. Receipt of the motive force generates driven motion of the implement holder. The electronic safety mechanism defines a disengaged configuration and an engaged configuration. The electronic safety mechanism includes a detection circuit configured to detect an actuation parameter and to generate a primary trigger signal based, at least in part, on the actuation parameter. The detection circuit also includes a detection circuit controller, which is programmed to control the operation of the detection circuit, and a supervisory circuit, which is configured to verify proper operation of the detection circuit controller.

Abstract: Safety brakes for circular saw blades, circular saws that include the safety brakes, and methods of operating circular saws are disclosed herein. The safety brakes include a sensor assembly, a brake assembly, and an actuator assembly. The sensor assembly is configured to detect an actuation parameter and to generate a trigger signal responsive to detection of the actuation parameter. The brake assembly includes a brake cam and a brake pad. The brake cam is configured to selectively transition between a disengaged configuration and an engaged configuration and is configured to operatively engage a planar side surface of the circular saw blade. The brake pad includes a pad friction material and is positioned such that the pad friction material faces toward the brake cam. The actuator assembly is configured to selectively transition the brake cam from the disengaged configuration to the engaged configuration responsive to receipt of the trigger signal.