Table saw with positive locking mechanism

A power tool in one embodiment includes a work-piece support surface, a swing arm assembly movable along a swing path between a first swing arm position whereat a portion of a shaping device supported by the swing arm assembly extends above the work-piece support surface and a second swing arm position whereat the portion of the shaping device does not extend above the work-piece support surface, a latch pin pivotable between a first position engaged with the swing arm assembly and a second position whereat the latch is not engaged with the swing arm assembly, an actuator configured to pivot the latch pin from the first position to the second position and to force the swing arm assembly away from the first swing arm position and toward the second swing arm position, and a control system configured to actuate the actuator in response to a sensed condition.