Method of optimizing memory wire actuator energy output

• US 10,445,533 B2
• Filed: 06/30/2017
• Issued: 10/15/2019
• Est. Priority Date: 06/30/2017
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Inventors: Gault, Joseph Benjamin, Bowers, Scott Douglas
• Primary Examiner(s): Feild, Lynn D
• Assistant Examiner(s): Almamun, Abdullah
• Application Number:
  US15/638,604
• Publication Number:
  US 20190005272A1
• Time in Patent Office: 837 Days
• CPC Class Codes: E05B 51/005 by a bimetallic or memory-shape element heated by electricity E05B47/0009; for panic door actuation E05B65/104
• CPC Class Codes: E05B 65/0067 for portable computers, e.g. for locking the screen panel to the keyboard panel
• CPC Class Codes: E05B 73/0052 of the magnetic type
• CPC Class Codes: E05B 73/0082 for office machines, e.g. PC's, portable computers, typewriters, calculators
• CPC Class Codes: F03G 7/06 using expansion or contraction of bodies due to heating, cooling, moistening, drying or the like using thermal expansion of non-vaporising liquids F01K
• CPC Class Codes: G06F 1/1616 with folding flat displays, e.g. laptop computers or notebooks having a clamshell configuration, with body parts pivoting to an open position around an axis parallel to the plane they define in closed position
• CPC Class Codes: G06F 1/1632 External expansion units, e.g. docking stations
• CPC Class Codes: G06F 1/1654 the display being detachable, e.g. for remote use
• CPC Class Codes: G06F 1/1669 Detachable keyboards
• CPC Class Codes: G06F 1/1679 for locking or maintaining the movable parts of the enclosure in a fixed position, e.g. latching mechanism at the edge of the display in a laptop or for the screen protective cover of a PDA G06F1/1681 takes precedence
• CPC Class Codes: G06F 21/85 interconnection devices, e.g. bus-connected or in-line devices
• CPC Class Codes: H01R 13/6397 with means for preventing unauthorised use
• CPC Class Codes: H04M 1/0249 Details of the mechanical connection between the housing parts or relating to the method of assembly
• CPC Class Codes: H04M 1/0254 comprising one or a plurality of mechanically detachable modules

Abstract

An apparatus for locking an electronic device includes an actuator, a return mechanism, and an arm. The actuator includes an actuator SMM wire that is configured to apply a contraction force. The return mechanism includes a return SMM wire that is configured to apply a return force opposite the contraction force. The arm is movable toward an unlocked position by the actuator and movable toward a locked position by the return force. The arm has at least one equilibrium position with less than 1 Newton of force on the arm from the actuator and less than 1 Newton of force on the arm from the return mechanism.

Claims

1. An apparatus for locking a computing device, comprising:

an actuator;

a locking protrusion connected to a first portion of the computing device;

a locking receptacle connected to a second portion of the computing device;

an actuator SMM wire having a first state and a second state and movable between the first state and the second state by the actuator, the first state having a first length and the second state having a second length that is shorter than the first length, wherein moving the actuator SMM wire from the first state to the second state applies a contraction force along a longitudinal direction of the actuator SMM wire; and

a return mechanism having a return SMM wire with a first state and a second state and movable between the first state and the second state by the return mechanism, the first state having a first length and the second state having a second length that is shorter than the first length, wherein moving the return SMM wire from the first state to the second state applies a return force along a longitudinal direction of the return SMM wire, the return force applied by the return SMM wire pulling the actuator SMM wire toward its first length.

2. The apparatus of claim 1, the return SMM wire including nickel titanium.

3. The apparatus of claim 1, the first state of the return SMM wire being a martensite microstructural phase and the second state being an austenite microstructural phase.

4. The apparatus of claim 1, the actuator SMM wire including nickel titanium.

5. The apparatus of claim 1, the first state of the actuator SMM wire being a martensite microstructural phase and the second state being an austenite microstructural phase.

6. The apparatus of claim 1, the return mechanism applying a return force only when an electric current is applied to the return SMM wire.

7. The apparatus of claim 1, an available force curve of the SMM wire being within a 10% variation of the maximum available force between the first state and the second state.

8. The apparatus of claim 1, the return force being oriented 180°

from the contraction force.

9. An apparatus for locking an electronic device, comprising:

an actuator containing an actuator SMM wire, the actuator SMM wire configured to apply a contraction force;

a return mechanism containing a return SMM wire, the return mechanism configured to apply a return force opposite the contraction force, the return force applied by the return SMM wire pulling the actuator SMM wire toward an initial position; and

an arm movable toward an unlocked position by the actuator and movable toward a locked position by the return mechanism;

the arm having at least one equilibrium position with less than 1 Newton of force on the arm from the actuator and less than 1 Newton of force on the arm from the return mechanism.

10. The apparatus of claim 9, the return SMM wire being oriented 180°

from the actuator SMM wire.

11. The apparatus of claim 9, the return mechanism including a mechanical linkage to convert a wire force of the return SMM wire to the return force.

12. The apparatus of claim 9, the actuator wire having a greater diameter than the return wire.

13. The apparatus of claim 9, the actuator wire and return wire having a diameter ratio at least 2.0.

14. The apparatus of claim 9, the actuator wire having a diameter of about 0.3 mm.

15. The apparatus of claim 9, the actuator configured to apply at least 300MPa to move the arm toward the unlocked position and the return mechanism configured to apply at least 100 MPa to move the arm toward the unlocked position.

16. A method of selectively securing an electronic device, the method including:

changing a state of an actuator SMM wire of a locking apparatus from a first state to a second state to apply a contraction force to move the locking apparatus toward an unlocked position; and

changing a state of a return SMM wire from a first state to a second state to apply a return force in a direction opposite the contraction force to move the locking apparatus toward a locked position, the return force applied by the return SMM wire pulling the actuator SMM wire toward the first state.

17. The method of claim 16, wherein there is less than 1 Newton of net force on the locking apparatus in the unlocked position.

18. The method of claim 16, wherein there is less than 1 Newton of net force on the locking apparatus in the locked position.

19. The method of claim 16, further comprising restoring the actuator SMM wire to the first state from the second state by applying a mechanical force with the return SMM wire.

20. The method of claim 19, further comprising restoring the return SMM wire to the first state from the second state by applying a mechanical force with an actuator.