Abstract: A power tool system includes a two-handed power tool having first and second start actuators, one for each hand of an operator. A controller prevents the power tool from initiating an operating cycle unless both actuators are turned ON to reduce the possibility of the operator's hands being disposed in a hazardous position during operation of the power tool. To discourage manual override of the dual-start-switch system, the controller prevents the power tool from initiating an additional operating cycle until both actuators have been switched OFF and then ON again. The second actuator includes a tubular sleeve that extends over part of the power tool to allow the sleeve to slide axially relative to the power tool between ON and OFF positions. Axial movement of the sleeve from its OFF position to its ON position turns ON the second start actuator.

Abstract: A positioning device having a chamber having a chamber exhaust valve in a first end and a chamber fluid inlet in a second end; a piston disposed in a chamber between the first end and the second end, the piston being slidable in the valve chamber between a first position toward the first end and a second position toward the second end; the fluid communication opening having a smaller cross-section area than the chamber exhaust valve; and a piston biasing spring urging the piston toward the chamber second end and away from the chamber first end, the piston biasing spring responsive to a fluid pressure differential between the first and second chamber ends above and below a predetermined level to move the piston into the first and second positions, respectively.