149 results about "Shape memory alloy actuators" patented technology

A contractible shape memory alloy (SMA) wire is used to throw a lever in a latch. The SMA actuator provides weight and space savings. In one embodiment, the SMA actuator is incorporated in the handle of the latch in order to provide a child lock or double lock function. The handle has a lever which includes a relatively short slot leg and a relatively long slot leg. A toggle sits in the slot. At least one SMA wire is connected to the toggle to move it between the relatively short slot leg, wherein the lever is prevented from pivoting, and the relatively long slot leg, where the lever is enabled to pivot. In another embodiment, the SMA actuator is embedded in the latch itself, and used to throw a lever that controls the child lock function.

An electromechanical cylinder lock includes an outer lock shell and a rotatable lock barrel located therein which is controlled by dual locking features. A side bar or fence selectively blocks and permits rotation of the barrel with respect to the shell in response to insertion of a key into a keyway in the barrel. A slider bar is movable between a blocking position in which the side bar is prevented from permitting rotation of the barrel, and an unblocking position in which the side bar permits rotation of the barrel. Alternately, a blocking mechanism is provided to block motion of tumbler pins in the cylinder lock. A shape memory alloy actuator, such as a wire made of NITINOL disposed in the barrel is activated by an electric current in response to determination by an electronic control device whether an attempt to open the lock is authorized. Thermal interlock protection from external heating of the lock is also provided.

A gas turbine engine includes a variable area nozzle having a plurality of flaps. The flaps are actuated by a plurality of actuating mechanisms driven by shape memory alloy (SMA) actuators to vary fan exist nozzle area. The SMA actuator has a deformed shape in its martensitic state and a parent shape in its austenitic state. The SMA actuator is heated to transform from martensitic state to austenitic state generating a force output to actuate the flaps. The variable area nozzle also includes a plurality of return mechanisms deforming the SMA actuator when the SMA actuator is in its martensitic state.

The present invention relates to a new forward-looking ultrasound device including a local actuator embedded inside an elongate member such as a guide wire or catheter. The present invention includes an ultrasound transducer element configured to engage with the local actuator and rotate about an axis of rotation at least when the ultrasound transducer element and the local actuator are engaged. Also disclosed are methods of using the same.

A controller (44) for a SMA actuator (2) includes an electgric power source (46) for applying an electric current through an SMA element (8), a sensor (48) to detect change in an electric resistance of the element (8); and a regulator (50) for controlling the magnitude of the applied electric current. The regulator (50) applies a first current above a safe limit current for the element (8) until a selected change in the electric resistance is detected and applies a second current less than the first current after the change is detected.

A heat converter engine comprising a crank shaft, an actuator assembly coupled to the crank shaft, and a heating means. The actuator assembly includes a plurality of shape memory elements that are malleable when below a critical temperature and return to their original shape when above the critical temperature. The heating means raises the temperature of a first portion of the shape memory elements above the critical temperature and a cooling means lowers the temperature of a second portion of the shape memory elements below the critical temperature. This action of heating and cooling the shape memory elements causes rotation of the crank shaft.

In a shape memory alloy actuator driving device, a predetermined constant current is applied to a shape memory alloy member as a retrieval signal to detect a terminal voltage of the shape memory alloy member, and a detection result of the terminal voltage is compared with a target voltage value to be calculated based on a target resistance value of the shape memory alloy member and a value of the constant current to cause a driving circuit to output, to the shape memory alloy member, a drive current that makes the detection result substantially equal to the target voltage value.

To provide a shape memory alloy actuator using a shape memory alloy that mechanically restrains a moving body in position to prevent oscillation, the actuator has a moving body pushing member adapted to be capable of abutting to the moving body, a bias spring for the moving body pushing member that exerts an external force on the moving body pushing member in the direction opposite to the direction of change in the shape of a shape memory wire caused by heating, a bias spring for the moving body that exerts an external force on the moving body in the direction same as the direction of change, a first stopper that restricts the movement of the moving body to a predetermined position upon cooling. One end of the shape memory wire is fixed, the other end is mechanically linked with the moving body pushing member. The moving body pushing member and the moving body are moved by deformation caused by heating, and the moving body and the moving body pushing member are separated, when the moving body is stopped at the position of the first stopper.

Linear actuators comprised of a plurality of geometric links connected together in displacement multiplied fashion by a plurality of SMA wires. The links may have a trigon or chevron configuration. The trigon links may be combined with a hexagonal or rhomboidal shaft to create a defined stacking pattern of links about the shaft. The shaft extends from the medial portion of the stack. Ohmic heating circuits connect to non-moving ends of SMA wires. Various groupings of links in parallel displacement are described.

Each cell of a fuel cell stack is provided, between the anode 37 and cathodes 38, with either (a) a permanent shunt (20) which may be a discrete resistor (42-44), a diode (95), a strip of compliant carbon cloth (65), or a small amount of conductive carbon black (22) in the ionomer polymer mixture of which the proton exchange membrane (39) is formed, or (b) a removeable shunt such as a conductor (69) which may be rotated into and out of contact with the fuel cell anodes and cathodes, or a conductor (85) which may be urged into contact by means of a shape memory alloy actuator spring (90, 91), which may be heated.

In one embodiment of the present invention, a shape memory alloy (“SMA”)-actuated flow controller comprises a number of grille members, each having a long axis and being slideable relative to one another parallel to that long axis. The SMA-actuated flow controller also includes a frame configured to guide the number of grille members, and an actuator disposed within the frame to move at least one of the number of grille members for varying a size of an aperture. Further, the actuator includes an SMA actuator that includes a number of SMA elements each connecting one grille number to another.

An actuated gauge pointer that includes a shape memory alloy element configured to move the gauge pointer when activated is provided. The actuated gauge pointer includes a first shape memory alloy element disposed within the perimeter of the gauge pointer housing. Additionally, the actuated gauge pointer may include a second shape memory alloy element to provide temperature compensation, and a bias member to return the gauge pointer to an initial condition.

A device for holding and deploying apparatus for use in space includes a fixed body and a movable body coaxially connected to each other through balls displaceable from a retention position to a release position, and a shape memory alloy actuator remote-controllable to displace the balls from the retention position to the release position and the ensuing separation of the moveable body from the fixed body under the action of axial thrust elastic means. The shape memory alloy actuator consists of a torsionally-deformable bar.

An apparatus for two degree of freedom positioning a moveable structure relative to a support structure is provided. The apparatus includes a moveable structure, a support structure, a compliant support disposed between the moveable structure and the support structure. The compliant support biases the moveable structure away from the support structure. In addition, three shape memory alloy actuators are provided between the structures and symmetrically arranged about the compliant support. The shape memory alloy actuators are selectively activated to provide two degrees of freedom of movement for the moveable structure relative to the support structure.

A resistance feedback circuit has a detecting section which detects a resistance of a shape memory alloy wire at the time of contraction and elongation, a calculating section which compares an output signal acquired from the detecting section and a signal input by a command section, and calculates an applied electric current corresponding to the resistance value detected, an output section which outputs the applied electric current which is output from the calculating section, to the shape memory alloy actuator, a control section which controls the detecting section, the calculating section and the output section, a storage section which stores a maximum value and a minimum value of the resistance which is measured in advance, and a command correcting section which corrects a signal output from the command section, based on the resistance value stored in the storage section, and a command signal which is output from the command correcting section is set to a resistance value which is higher than the minimum resistance value by a correction value.

A rotary SMA actuator includes an SMA assembly having a plurality of grooves formed therein to form a plurality of concentrically arranged SMA tubes. A heater element is disposed against an input end of the SMA tubes and generates heat when electrical current is applied thereto. The heat is used to heat the SMA tubes, which causes an angular deflection of each of the tubes at an output end thereof. An innermost one of the SMA tubes is used as an output member and its angular deflection is the sum of the angular deflections of all of the SMA tubes. The actuator is of a smaller size and lighter weight than electrical, mechanical, hydraulic or pneumatic actuators of comparable torque output. The actuator also provides greater deflection capability than similarly sized SMA type actuators that do not employ concentric tubes.

Method and apparatus for controlling a shape of a composite structure. A shape memory structure associated with the composite structure is activated. The shape memory structure changes from a buckled shape to an original shape and causes the composite structure to change from an undeployed shape to a deployed shape. The shape memory structure is deactivated. The shape memory structure changes from the original shape to the buckled shape in response to a load from the composite structure and causes the composite structure to change from the deployed shape to the undeployed shape.