Inertial energy scavenger

• US 20080129153A1
• Filed: 05/15/2007
• Published: 06/05/2008
• Est. Priority Date: 06/30/2006
• Status: Abandoned Application

• Current Assignee: Sensors Licensing LLC
• Original Assignee: Sensors Licensing LLC
• Inventors: Tola, Jeffrey F., Roundy, Shadrach J., Tola, Jeffry
• Application Number:
  US11/803,900
• Publication Number:
  US 20080129153A1
• Time in Patent Office: Days
• US Class Current: 310/339
• CPC Class Codes: H02N 2/186 Vibration harvesters
• CPC Class Codes: H10N 30/306 Cantilevers

Abstract

The present invention provides an inertial energy scavenger that includes at least one piezoelectric element held by a housing, a proof mass that is movable within the housing in a direction parallel to the piezoelectric element, and a mechanical assembly disposed between the proof mass and the piezoelectric element. The mechanical assembly transfers work from the proof mass to the piezoelectric element, where the work from the proof mass is a first force along a first distance and the work to the piezoelectric element is a second force along a second distance. The first distance is greater than the second distance and the first force is smaller than the second force. Force amplification is determined by the geometry of the mechanical transfer assembly and can range anywhere from just above 1 to at least 10, where some embodiments include a bi-lever configuration, a tube-shaped configuration and a reverse actuation configuration.

Claims

1. An inertial energy scavenger comprising:

a. at least one piezoelectric element held by a housing;

b. a proof mass that is movable within said housing, wherein said movement is in a direction parallel to said piezoelectric element; and

c. a mechanical assembly disposed between said proof mass and said piezoelectric element, wherein said mechanical assembly transfers work from said proof mass to said piezoelectric element, whereby said work from said proof mass comprises a first force along a first distance and said work to said piezoelectric element comprises a second force along a second distance, whereas said first distance is greater than said second distance and said first force is smaller than said second force.

2. The inertial energy scavenger of claim 1, wherein said piezoelectric element is a cantilever piezoelectric element having a first end connected to said housing and a second end coupled to said mechanical assembly.

3. The inertial energy scavenger of claim 2, wherein said cantilever first end is larger than said cantilever second end.

4. The inertial energy scavenger of claim 1, wherein said piezoelectric element is a fixed-fixed supported piezoelectric element having a first end and a second end connected to said housing and a middle section coupled to said mechanical assembly.

5. The inertial energy scavenger of claim 1, wherein said housing comprises at least one displacement control surface interfacing said piezoelectric element, wherein said control surface is curved.

6. The inertial energy scavenger of claim 1, wherein said proof mass within said housing has at least one stable equilibrium point, whereby when at said stable equilibrium point said piezoelectric element is at a minimum deflection.

7. The inertial energy scavenger of claim 1, wherein said proof mass within said housing has at least one unstable equilibrium point, whereby when in said unstable equilibrium point said piezoelectric element is at a maximum deflection.

8. The inertial energy scavenger of claim 1, wherein said mechanical assembly comprises at least one bi-lever work transfer element and at least one piezoelectric element coupler.

9. The inertial energy scavenger of claim 8, wherein said bi-lever work transfer element comprises:

a. a proof mass connection end, wherein said connection end connects said proof mass to said bi-lever;

b. a top lever, wherein said top lever comprises;

i. a top lever first end;

ii. a top lever middle section; and

iii. a top lever second end, whereby said top lever first end is attached to said proof mass connection end, whereas said top lever middle section extends in a first diagonal direction from said connection end;

c. a coupler span, wherein said coupler span comprises;

i. a coupler span top end;

ii. a coupler span middle section; and

iii. a coupler span bottom end, whereby said coupler span top end is connected to said second end of said top lever, whereas said coupler span middle section is disposed along said piezoelectric element;

d. a bottom lever, wherein said bottom lever comprises;

i. a bottom lever first end;

ii. a bottom lever middle section; and

iii. a bottom lever second end, whereby said bottom lever first end is attached to said coupler span bottom end, whereas said bottom lever middle section extends in a second diagonal direction from said coupler span bottom end, wherein said bottom lever second end slidably contacts a planar surface within said housing, whereby said planar surface is perpendicular to said movement of said proof mass.

10. The inertial energy scavenger of claim 8, wherein said piezoelectric element coupler comprises a coupler span retaining surface and a coupler cavity, whereby said retaining surface slidably holds said coupler span and said coupler cavity fixedly holds a movable end of said piezoelectric element, whereas said coupler pushes and pulls said piezoelectric element according to motion by said proof mass.

11. The inertial energy scavenger of claim 8, wherein said piezoelectric element coupler comprises a coupler span retaining surface and a coupler cavity, whereby said retaining surface fixidly holds said coupler span and said coupler cavity slidably holds a movable end of said piezoelectric element, whereas said coupler pushes and pulls said piezoelectric element according to motion by said proof mass.

12. The inertial energy scavenger of claim 8, wherein said coupler span middle section comprises a sliding surface, whereby said sliding surface enables said coupler span middle section to slide on said piezoelectric element as said proof mass moves, whereas said coupler span middle section moves said piezoelectric element.

13. The inertial energy scavenger of claim 8, wherein said coupler span middle section comprises a rounded surface, wherein said round surface rolls on said piezoelectric element as said proof mass moves, whereas said coupler span middle section moves said piezoelectric element.

14. The inertial energy scavenger of claim 1, wherein said housing comprises;

a. a track having a first end and a second end, whereby said proof mass moves therein;

b. a first proof mass stop disposed at said track first end and a second proof mass stop disposed at said track second end; and

c. a first restoring spring disposed at said first stop and a second restoring spring disposed at said second stop.

15. The inertial energy scavenger of claim 14, wherein said mechanical assembly comprises:

a. at least one actuation channel disposed transverse to a longitudinal length of said track, and

b. a mechanical transfer element, whereby said actuation channel holds said mechanical transfer element and said mechanical transfer element is moveable within said actuation channel, whereas said mechanical transfer element abuts said piezoelectric element, and wherein said proof mass abuts said mechanical transfer element and moves said mechanical transfer element within said actuation channel, whereby said mechanical transfer element moves said piezoelectric element as said proof mass moves between said restoring springs according to forces applied to said housing.

16. The inertial energy scavenger of claim 14, wherein said mechanical transfer element is an actuation ball, whereas said actuation ball rolls within said actuation channel.

17. The inertial energy scavenger of claim 14, wherein said mechanical transfer element is an actuation cylinder, whereas said actuation cylinder has a rounded top and a rounded bottom, whereby said actuation cylinder is slidable within said actuation channel.

18. The inertial energy scavenger of claim 14, wherein said housing holds said piezoelectric element outside of said track.

19. The inertial energy scavenger of claim 14, wherein said proof mass is a spherical proof mass.

20. The inertial energy scavenger of claim 14, wherein said track is a tube.

21. The inertial energy scavenger of claim 14, wherein said tack is a curved tube.

22. The inertial energy scavenger of claim 20, wherein said curved tube is selected from a group consisting of a constant-radius tube and a variable-radius tube.

23. An inertial energy scavenger comprising:

a. at least one piezoelectric element held by a translating housing, wherein said translation is in a direction parallel to said piezoelectric element;

b. a proof mass held in said housing;

c. at least one actuator channel, wherein said actuator channel is along said translation direction;

d. a stationary base, wherein said base comprises at least one actuator disposed perpendicular to said base, whereby said actuator channel holds said actuator therein when said housing translates; and

e. a mechanical assembly disposed between said actuator channel and said piezoelectric element, wherein said mechanical assembly transfers work from said proof mass to said piezoelectric element when acted on by said actuator, whereby said work from said proof mass comprises a first force along a first distance and said work to said piezoelectric element comprises a second force along a second distance, whereas said first distance is greater than said second distance and said first force is smaller than said second force.

24. The inertial energy scavenger of claim 23, wherein said proof mass is an effective proof mass, whereby said effective proof mass comprises:

a. at least one roller having a roller axis perpendicular to said translation direction;

b. at least one said piezoelectric element;

c. said housing;

d. said mechanical assembly; and

e. energy scavenger electronics, whereby work from said effective proof mass comprises an effective force along said first distance and work to said piezoelectric element comprises a second effective force along said second distance, whereas said first distance is greater than said second distance and said first effective force is smaller than said second effective force.

25. The inertial energy scavenger of claim 23, wherein said piezoelectric element is a cantilever piezoelectric element having a first end connected to said housing and a second end coupled to said mechanical assembly.

26. The inertial energy scavenger of claim 25, wherein said cantilever first end is larger than said cantilever second end.

27. The inertial energy scavenger of claim 23, wherein said piezoelectric element is a fixed-fixed supported piezoelectric element having a first end and a second end connected to said housing and a middle section coupled to said mechanical assembly.

28. The inertial energy scavenger of claim 23, wherein said housing comprises at least one displacement control surface interfacing said piezoelectric element, wherein said control surface is curved.

29. The inertial energy scavenger of claim 23, wherein said proof mass comprises at least one roller having a roller axis perpendicular to said translation direction, whereby said axis couples to a bearing in said housing.

30. The inertial energy scavenger of claim 23, wherein said actuator comprises an angled surface disposed perpendicular to said base.

31. The inertial energy scavenger of claim 23, wherein said mechanical assembly comprises;

a. a work transfer port, wherein said transfer port spans from an inside wall of said actuator channel through an outside wall of said housing; and

b. a work transfer element, wherein said transfer element moves within said transfer port when acted on by said actuator.

32. The inertial energy scavenger of claim 31, wherein said work transfer element is selected from a group consisting of a roller ball, and a sliding cylinder.

33. The inertial energy scavenger of claim 23, wherein said base further comprises restoring springs, whereby said restoring springs are disposed to oppose said housing translation.