Patent ID: 7178648

Claim:
A viscous coupling comprising: an output member including a body and an impeller cover; an input member coupled within said output member; a working chamber including an operating chamber defined between said body and said input member; a reservoir plate coupled within said output member and between said input member and said impeller cover, said reservoir plate having a first side and a second side; a fluid reservoir defined between said first side and said impeller cover, said fluid reservoir having a quantity of viscous fluid; a fluid port on said reservoir plate fluidically coupling said working chamber and said fluid reservoir; a spring loaded valve arm pivotably coupled to said first side of said reservoir plate; and a single electrically-activated, temperature-sensitive wire coupled to said spring loaded valve arm for controlling the relative positioning of said spring loaded valve arm to cover and uncover said fluid port; said spring loaded valve arm comprising; a valve arm pivotally coupled to said first side of said reservoir plate via a coupling pin; and a coil spring coupled around said coupling pin, said coil spring urging said valve arm to a first position, said first position selected from the group consisting of a closed position and an open position, said closed position defined wherein said valve arm covers said fluid port and said open position defined wherein said valve arm does not cover said fluid port.