Patent ID: 6742761
Filing Date: 2004-06-01
Classification: B64G,F16K

Abstract:
A latching valve of miniature size for on or off control of the flow of a fluid, the latching valve comprising a valve closure having a poppet and a seat, the poppet being moveable between open and closed positions with respect to the seat for respectively opening and closing flow of the fluid through the seat, an actuator mechanism having a structure that moves the poppet between the closed and open positions, the structure comprising an actuator element comprised of a shape memory alloy which undergoes a crystalline phase transformation and resulting shape change from a low temperature deformable phase to a high temperature memory phase when the element is heated through the alloy's phase change transformation temperature, the element being positioned for moving the poppet responsive to the shape change, and a latching mechanism comprising a spring having a conical wall which has properties that are sufficient to cause the wall to change shape between first and second axial bistable positions responsive to an axial force, the wall being characterized in: sloping at an angle &agr; from a circular outer rim having a diameter D to a circular inner rim having a diameter d, having a thickness t, having an axial height h between the rims, and being formed of a metal, the wall in the first position holding the poppet in the open position and the wall in the second position holding the poppet in the closed position.