US Patent 9550288 Fastener-driving tool including a reversion trigger

A fastener-driving tool includes a housing and a workpiece-contacting element movable between a rest position and an activated position. The tool also includes a trigger connected to the housing and movable between a rest position and an activated position, a control valve including an actuating pin, an actuation lever movably connected to the trigger and movable between a rest position and an actuating position adjacent to the actuating pin, and a trigger control mechanism associated with the actuation lever and configured for moving and holding the actuation lever in the actuating position. In a powered mode, the trigger control mechanism causes the-actuation lever to move and remain in the actuating position such that the tool is actuated each time the workpiece-contacting element contacts a workpiece and moves to the activated position causing the actuation lever to contact the actuating pin and initiate an actuation of the tool.