Abstract: A fluid actuatable fan clutch having an energy absorbing internal caliper action, including a pulley or sheave rotatably mounted on a fixed shaft; an annular friction facing connected to an internal surface of the sheave; a fan blade hub rotatably mounted on the shaft adjacent the sheave, the hub having an annular piston cavity or cylinder having a piston located therein facing the friction facing, the piston being normally urged out of contact with the friction facing by a suitable spring member; an annular thrust cap located on the side of said friction facing opposite the piston, the thrust cap being connected to the fan hub and being normally out of contact with the friction facing; and suitable passageways for supplying air or other fluid to the back side of said piston for urging the piston into contact with said friction facing and against said thrust cap to thereby engage the fan hub with the sheave.

Abstract: A thermostatically operated air valve having a valve body, a valve chamber located within the body, a thermal sensor having a push rod extending therefrom into said valve chamber at a first end thereof, a reciprocal valve rod located in the valve chamber with an axial opening therein communicating with a supply of air under pressure, said axial opening of the valve rod communicating with a cylinder located at the second end of said valve chamber, a piston located within said cylinder and slidably mounted on the valve rod for rapid reciprocal movement thereon, an exhaust port in said cylinder having a retractable valving member seated in sealing relationship within said exhaust port, said push rod being in abutting relationship with said valve rod, said push rod extending at a predetermined actuation temperature to push said valve rod into contact with said valving member thereby sealing said axial opening in the valve rod and unseating said valving member from said exhaust port, whereby air in said cylinder i