Shape memory actuator

A shape memory actuator for positioning a control member, said actuator comprising a first shape memory means for moving the control member in one direction, a second shape memory means for moving the control member in the other direction, said first means including a shape memory element having predetermined upper and lower phase transition temperatures, said first element assuming a predetermined memory shape when heated to said upper phase transition temperature, said second means including a shape memory element having predetermined upper and lower phase transition temperatures, said second element assuming a predetermined memory shape when heated to said upper phase transition temperature;

• means for selectively raising the temperature of said first element or said second element to its upper phase transition temperature whereby the control member will be moved in said one or said other direction and means for holding the control member in a fixed position when the heated element is allowed to cool.

A shape memory actuator for positioning a control member, said actuator comprising:

• a first shape member means for moving the control member in one direction;
• a second shape memory means for moving the control member in the other direction;
• said first means including a shape memory element having predetermined upper and lower phase transition temperatures, said first element assuming a predetermined memory shape when heated to said upper phase transition temperature, said second means including a shape memory element having predetermined upper and lower phase transition temperatures, said second element assuming a predetermined memory shape when heated to said upper phase transition temperature, means for selectively raising the temperature of said first element or said second element to its upper phase transition temperature whereby the control member will be moved in said one or said other direction, electrically conductive means connecting ne end of said first and second shape memory means to the control member and the other ends to fixed pivot pins, said conductive means comprising a thin flat strip having a pair of legs at one end and a curved hook at the other end, said legs being connected to said shape memory elements and said curved hook being connected to the control member and to said pivot pins.

A shape memory actuator for controlling the position of a control member, said actuator comprising:

• a pair of electrically conductive shape memory elements, one of said elements being connected to move the control member toward an open position and the other of said elements being connected to move the control member toward a closed position,
• each of said elements having a shape memory transition temperature above which said elements assume their memory shape, and a lower temperature below which they can be stretched from their memory shape, said elements being connected to the control member so that the electrically energized element pulls the other element from its memory shape to a stretched shape and means for electrically energizing one or the other of said elements to open or close the control member.

A shape memory actuator for incrementally positioning a control member, said actuator comprising:

• a pair of electrically conductive shape memory elements, the first of said elements being connected to move the control member toward a first position and the second of said elements being connected to move the control member toward a second position;
• and each of said elements having an austenite phase and a lower temperature phase whereby the stresses in said elements are balanced in any position of the control member and means for electrically energizing one or the other of said elements to position said control member.