Apparatus and methods for a shape memory spring actuator and display

• US 6,705,868 B1
• Filed: 03/18/1998
• Issued: 03/16/2004
• Est. Priority Date: 03/18/1998
• Status: Expired due to Fees

• Current Assignee: Purdue Research Foundation (Purdue University)
• Original Assignee: Purdue Research Foundation (Purdue University)
• Inventors: Schleppenbach, David A., Said, Joe P., Lau, Wunji
• Primary Examiner(s): RIMELL, SAMUEL G
• Application Number:
  US09/040,871
• Time in Patent Office: 2,190 Days
• Field of Search: 434/112, 434/113, 434/114, 434/115, 184/75, 337/140, 605/27, 605/28, 605/29, 604/95.05, 600/143, 600/151, 600/206
• US Class Current: 434/114
• CPC Class Codes: G09B 21/004 Details of particular tactile cells, e.g. electro-mechanical or mechanical layout

Abstract

Various apparatus and methods for an actuator and display using one more shape memory springs. A shape memory spring is heated and urges a pin to a first or extended position. The pin may be supported in the first position by a supporting mechanism. The shape memory spring is heated electically, and in some embodiments under the control of a processor. The present invention may be used to display information provided in user interface from a computer program, including text, numerical data, and graphical images.

Claims

1. An apparatus comprising:

a first spring made from a shape-memory material;

a first thermoelectric heating element for heating said first spring using the Peltier effect;

a second spring;

a pin urged in a first direction by said first spring after said first spring is heated, said pin being urged in a second direction by said second spring, the first direction being generally opposite of said second direction; and

a member including a hole;

wherein a portion of said pin passes through the hole after said first spring is heated, said thermoelectric heating element is in contact with one end of said first spring, and wherein said thermoelectric heating element has an inner diameter that is greater than the outer diameter of said first spring, and a portion of said thermoelectric heating element surrounds a portion of said first spring.

2. The apparatus of claim 1 wherein said first spring is a compression coil spring.

3. The apparatus of claim 1 wherein said first spring is a tension coil spring.

4. The apparatus of claim 1 wherein said second spring is made from a shape-memory material, and which further comprises a second heating element for heating said second spring.

5. The apparatus of claim 4 wherein said second spring is a compression coil spring.

6. The apparatus of claim 4 wherein said second spring is a tension coil spring.

42. The apparatus of claim 1 wherein said thermoelectric heating element has an outer diameter that is less than the inner diameter of said first spring, and a portion of said thermoelectric heating element is within a portion of the interior of said first spring.

7. An apparatus for displaying a braille character comprising:

a member defining at least six holes;

at least six actuators, each said actuator including a pin, a shape-memory spring for urging the pin in a direction, and a thermoelectric heater to heat said spring; and

an electrical circuit for receiving an input electrical signal, said electrical circuit being in electrical communication with said heaters, said heaters being operable to heat in response to an output signal from electrical circuit;

wherein said pin of each said actuator is aligned with a hole, a portion of said pin being capable of passing through a hole in response to heating by one of said heaters.

8. The apparatus of claim 7 wherein said springs are compression coil springs.

9. The apparatus of claim 8 which further comprises at least eight actuators configured and adapted to display a braille character.

10. The apparatus of claim 7 wherein each said actuator includes a supporting mechanism for fixedly supporting said pin in a first position wherein a portion of said pin extends beyond the surface of said member.

11. The apparatus of claim 7 wherein said shape-memory spring urges a pin in the first direction, and wherein each actuator includes a second spring for urging the pin in a second direction opposite to the first direction.

12. A system comprising:

a processor operating a program with a user interface, said processor having an output electrical signal corresponding to the user interface; and

a haptic display comprising a plurality of actuators, each said actuator including a pin capable of extending and retracting, a shape-memory spring for urging the pin in a direction, and a thermoelectric heater to heat said spring, said display including an electrical circuit for receiving the output electrical signal, said electrical circuit being in electrical communication with said heaters and operable to cause said heaters to heat said springs in response to the output signal;

wherein some of said pins of said display are in a pattern in response to the output signal, the pattern corresponding to the user interface.

13. The system of claim 12 which further comprises a clock, wherein the user interface is the time or the date.

14. The system of claim 12 which further comprises an automated teller machine, wherein the user interface includes financial data.

15. The system of claim 12 wherein said actuator includes a supporting mechanism for maintaining said pin in the extended position.

16. The apparatus of claim 12 wherein said shape-memory spring urges a pin in the first direction, and wherein each actuator includes a second spring for urging the pin in a second direction opposite to the first direction.

17. The apparatus of claim 12 wherein each said actuator includes a supporting mechanism for fixedly supporting said pin in an extended position.

18. An apparatus comprising:

a first pin having a first position;

a second pin having two ends and a projection intermediate of the two ends;

a first spring constructed and arranged for biasing said first pin and said second pin toward the first position, said first spring being fabricated from a shape-memory material;

a member defining a guide slot for said projection, said guide slot including a first rest for supporting said projection such that the first rest supports said projection when said first pin is in the first position; and

a heater for heating said first spring;

wherein said first spring urges said first pin toward the first position in response to a first heating of said first spring.

19. The apparatus of claim 18 which further comprises a second spring constructed and arranged for biasing one of said first pin or said second pin in a direction away from the first position.

20. The apparatus of claim 18 which further comprises a capacitive discharge electrical power supply for providing electrical power to said heater, wherein said electrical power supply provides a variable voltage including a first voltage for quickly heating said first spring followed by a second voltage less than the first voltage.

21. The apparatus of claim 18 wherein said heater is a thermoelectric heating element using the Peltier effect for heating said first spring.

22. An apparatus comprising:

a pin having a first position;

a spoked member having a plurality of long sections;

a first spring for biasing said pin toward the first position, said first spring being fabricated from a shape-memory material;

a member defining a hole and including a rest and a channel arranged around the circumference of the hole, said channel permitting passage of a long section therethrough, said rest supporting a long section when said pin is in the first position; and

a heater for heating said first spring;

wherein said first spring urges said first pin toward the first position in response to a first heating of said first spring, and said spoked member supports said pin in the first position.

23. The apparatus of claim 22 wherein said spoked member includes a first plurality of teeth, and which further comprises a contact member with a second pluality of teeth, urging of said contact member toward the first position results in engagement of the first plurality of teeth with the second plurality of teeth.

24. The apparatus of claim 22 wherein said spring is a compression coil spring.

25. The apparatus of claim 22 wherein said heater is a thermoelectric heater using the Peltier effect.

26. An apparatus comprising:

a first spring fabricated from a shape memory material;

a first pin having a projection, said first pin being urged in a first direction by said first spring;

a member including a first guiding surface and a second guiding surface, each surface being adapted for sliding contact with said projection, the first guiding surface including a first rest, said member defining two channels; and

a heater for heating said first spring, wherein said heater is capable of applying a first amount of heat to said first spring and a second amount of heat to said first spring, the second amount being greater than the first amount;

wherein said projection moves from the first channel and along the first guiding surface to the first rest in response to heating said first spring by a first amount, and said projection moves from the first channel along the second guiding surface to the second channel in response to heating said first spring by a second amount.

27. The apparatus of claim 26 which further comprises a second spring for urging said first pin in a second direction generally opposite the first direction.

28. The apparatus of claim 26 which further comprises a second pin and a third pin, said first pin being intermediate of said second pin and said third pin.

29. The apparatus of claim 28 wherein said second pin represents a portion of a haptic braille display.

30. The apparatus of claim 26 wherein said first pin has an end with a first plurality of teeth, said second pin has an end with a second plurality of teeth, said first plurality of teeth being engageable with said second plurality of teeth.

31. The apparatus of claim 26 wherein said projection moves from the first rest to one of said first channel or said second channel in response to heating said first spring by the first amount or the second amount.

32. An apparatus comprising:

a coil spring fabricated from a shape memory material, said spring having a first section and a second section; and

an electrical power supply having a first circuit for heating the first section and a second circuit for heating said second section;

wherein said spring exhibits a first response to heating the first section, a second response to heating the second section, and a third response to heating the first section and the second section, the third response being different than the first response or the second response, and wherein said first section has a first number of coils, said second section has a second number of coils, and the first number is different than the second number.

33. The apparatus of claim 32 which further comprises a pin urged in a first direction by said spring, a member with a surface and defining a hole, wherein the first response of said spring causes a portion of said pin to pass through the hole.

34. The apparatus of claim 33 which further comprises a supporting mechanism for fixedly supporting said pin in a first position wherein a portion of said pin extends beyond the surface of said member.

35. The apparatus of claim 32 wherein the coils of said first section have a first pitch, the coils of the second section have a second pitch, and the first pitch is different than the second pitch.

36. The apparatus of claim 32 wherein said first section has a first outer diameter, said second section has a second outer diameter, and the first outer diameter is different than the second outer diameter.

37. The apparatus of claim 32 wherein said spring is a compression coil spring.

38. The apparatus of claim 32 wherein said first circuit heats said first section by passing current through the first section, and said second circuit heats said second section by passing current through the second section.

39. The apparatus of claim 32 which further comprises a first heater for heating paid first section and a second heater for heating said second section, said first heater being proximate to said first section and said second heater being proximate to said second section.

40. The apparatus of claim 39 wherein said first heater is a resistance heater.

41. The apparatus of claim 39 wherein said first heater is a thermoelectric heater using the Peltier effect.