Magnetic spring and ventricle assist device employing same

• US 20010003802A1
• Filed: 01/16/2001
• Published: 06/14/2001
• Est. Priority Date: 04/30/1996
• Status: Abandoned Application

• Current Assignee: Foster Bio Technology Corporation
• Original Assignee: Foster Bio Technology Corporation
• Inventors: Vitale, Nicholas G.
• Application Number:
  US09/761,436
• Publication Number:
  US 20010003802A1
• Time in Patent Office: Days
• US Class Current: 623/3.11
• CPC Class Codes: A61M 60/148 in line with a blood vessel using resection or like techniques, e.g. permanent endovascular heart assist devices
• CPC Class Codes: A61M 60/178 drawing blood from a ventricle and returning the blood to the arterial system via a cannula external to the ventricle, e.g. left or right ventricular assist devices
• CPC Class Codes: A61M 60/196 replacing the entire heart, e.g. total artificial hearts [TAH]
• CPC Class Codes: A61M 60/422 the force acting on the blood contacting member being electromagnetic, e.g. using canned motor pumps
• CPC Class Codes: A61M 60/446 the axis of both movements being parallel, e.g. roller screw actuators or cylindrical cam transmissions
• CPC Class Codes: A61M 60/459 generated by permanent magnets
• CPC Class Codes: A61M 60/538 Regulation using real-time blood pump operational parameter data, e.g. motor current
• CPC Class Codes: H02K 49/10 of the permanent-magnet type
• CPC Class Codes: H02K 7/06 Means for converting reciprocating motion into rotary motion or vice versa
• CPC Class Codes: H02K 7/11 with dynamo-electric clutches

Abstract

A magnetic spring includes a plurality of spaced-apart stationary circumferentially magnetized segments disposed along a circle about an axis to define a first plurality of spaced-apart gaps, and a plurality of spaced-apart moveable circumferentially magnetized segments disposed along the circle to define a second plurality of spaced-apart gaps. Each of the plurality of moveable magnetized segments is axially slidable within a respective one of the first plurality of gaps defined by the plurality of stationary magnetized segments. Significant applications of the magnetic spring in an actuator of a ventricle assist device (VAD) or a total artificial heart (TAH) in which stored energy in the magnetic spring is used to reduce motor power loses of an actuator during a power stroke of the VAD or TAH.

Claims

1. A magnetic spring comprising:

a plurality of spaced-apart stationary magnetized segments defining a first plurality of spaced-apart gaps;

a plurality of spaced-apart moveable magnetized segments defining a second plurality of spaced-apart gaps; and

wherein each of said plurality of moveable magnetized segments is slidable within a respective one of said first plurality of gaps defined by said plurality of stationary magnetized segments.

2. The magnetic spring of

claim 1

wherein said plurality of stationary magnetized segments and said plurality of moveable magnetized segments are disposed along an arc.

3. The magnetic spring of

claim 1

wherein said plurality of stationary magnetized segments and said plurality of plurality of moveable magnetized segments generally define a hollow cylinder.

4. The magnetic spring of

claim 1

wherein at least one of said plurality of stationary magnetized segments comprises a tapering cross-section.

5. The magnetic spring of

claim 1

wherein at least one of said plurality of moveable magnetized segments comprises a tapering cross-section.

6. The magnetic spring of

claim 1

wherein longitudinally-extending side portions of said plurality of stationary magnetized segments comprise a first orientated polarity and longitudinally-extending side portions of said plurality of moveable magnetized segments comprise a second orientated polarity.

7. The magnetic spring of

claim 1

wherein said plurality of stationary magnetized segments and said plurality of moveable magnetized segments when aligned within said gaps tend to move away from each other.

8. The magnetic spring of

claim 1

wherein said plurality of stationary magnetized segments and said plurality of moveable magnetized segments when aligned within said gaps tend to remain aligned.

9. A magnetic spring comprising:

a plurality of spaced-apart stationary magnetized segments disposed along an arc about an axis and defining a first plurality of spaced-apart gaps;

a plurality of spaced-apart moveable magnetized segments disposed along said arc and defining a second plurality of spaced-apart gaps;

wherein each of said plurality of moveable magnetized segments is axially slidable within a respective one of said first plurality of gaps defined by said plurality of stationary magnetized segments; and

wherein each of the plurality of stationary magnetized segments have a first circumferentially orientated polarity and each of the plurality of moveable magnetized segments have a second circumferentially orientated polarity.

10. The magnetic spring of

claim 9

wherein said plurality of stationary magnetized segments and said plurality of moveable magnetized segments generally define a hollow cylinder.

11. The magnetic spring of

claim 9

wherein at least one of said plurality of stationary magnetized segments and said plurality of moveable magnetized segments comprises an axially tapering cross-section when viewed normal to an outer tangential surface of the at least one magnetized segment.

12. The magnetic spring of

claim 11

wherein at least one of said plurality of stationary magnetized segments and said plurality of moveable magnetized segments comprises an axially tapering cross-section when viewed parallel to an outer tangential surface of the at least one segment.

13. The magnetic spring of

claim 9

wherein said first circumferentially orientated polarity is the same as the second circumferentially orientated polarity so that said plurality of stationary magnetized segments and said plurality of moveable magnetized segments when aligned within said gaps tend to move away from each other.

14. The magnetic spring of

claim 9

wherein said first circumferentially orientated polarity is opposite of the second circumferentially orientated polarity so that said plurality of stationary magnetized segments and said plurality of moveable magnetized segments when aligned within said gaps tend to remain aligned.

15. An actuator for a ventricle assist device (VAD) or a total artificial heart (TAH), said actuator comprising:

a driver for generating a first force for driving the VAD or TAH; and

a magnetic spring for magnetically applying a second force for driving the VAD or TAH.

16. The actuator of

claim 15

wherein said magnetic spring comprises a plurality of spaced-apart stationary magnetized segments defining a first plurality of spaced-apart gaps, a plurality of spaced-apart moveable magnetized segments defining a second plurality of spaced-apart gaps, and wherein each of said plurality of moveable magnetized segments is slidable within a respective one of said first plurality of gaps defined by said plurality of stationary magnetized segments.

17. The actuator of

claim 16

wherein said plurality of stationary magnetized segments and said plurality of plurality of moveable magnetized segments generally define a hollow cylinder.

18. The actuator of

claim 16

wherein at least one of said plurality of stationary magnetized segments and said plurality of moveable magnetized segments comprises a tapering cross-section.

24. A ventricle assist device (VAD) comprising:

a housing having a first ventricle;

a first diaphragm coupled to the first ventricle for pumping blood therefrom when actuated towards said housing; and

an actuator of

claim 15

for actuating said first diaphragm.

26. A total artificial heart (TAH) comprising:

a housing having a first ventricle and a second ventricle;

a first diaphragm coupled to the first ventricle for pumping blood therefrom when actuated towards said housing, and a second diaphragm coupled to the second ventricle for pumping blood therefrom when actuated towards said housing; and

an actuator of

claim 15

for actuating said first diaphragm and said second diaphragm.

19. An actuator for a ventricle assist device (VAD) or a total artificial heart (TAH), said actuator comprising:

a rotatable member;

a translatable member for driving the VAD or TAH;

a driver for imparting rotary torque to the rotatable member;

a magnetic coupling for converting rotary torque of the rotatable member to a first axial force on the translatable member; and

a magnetic spring for magnetically applying a second axial force on the translatable member, said magnetic spring comprising a plurality of spaced-apart stationary magnetized segments defining a first plurality of spaced-apart gaps, a plurality of spaced-apart moveable magnetized segments defining a second plurality of spaced-apart gaps, and wherein each of said plurality of moveable magnetized segments is slidable within a respective one of said first plurality of gaps defined by said plurality of stationary magnetized segments.

20. The actuator of

claim 19

wherein said plurality of stationary magnetized segments and said plurality of moveable magnetized segments generally define a hollow cylinder.

21. The actuator of

claim 19

wherein at least one of said plurality of stationary magnetized segments and said plurality of moveable magnetized segments comprises a tapering cross-section.

22. The actuator of

claim 19

, wherein said magnetic coupling comprises a first permanent magnet comprising part of said rotatable member and a second permanent magnet comprising part of said translatable member, and wherein said first permanent magnet comprises interleaved, helical magnet sections of alternating polarities, and wherein said second permanent magnet comprises interleaved, helical magnet sections of alternating polarities.

23. The actuator of

claim 22

, wherein said actuator is designed to reside within a Cleveland Clinic—

type total artificial heart having a first diaphragm at a first ventricle and a second diaphragm at a second ventricle, and wherein said driver comprises a permanent magnet rotary motor which imparts oscillating motion to the rotatable member producing an oscillating rotary torque at the first permanent magnet that in turn produces reciprocating axial movement in the second permanent magnet, and hence the translatable member, said reciprocating axial movement being employed to alternately actuate the first diaphragm of the first ventricle and the second diaphragm of the second ventricle.

25. A ventricle assist device (VAD) comprising:

a housing having a first ventricle;

a first diaphragm coupled to the first ventricle for pumping blood therefrom when actuated towards said housing; and

an actuator of

claim 19

for actuating said first diaphragm.

27. A total artificial heart (TAH) comprising:

a housing having a first ventricle and a second ventricle;

a first diaphragm coupled to the first ventricle for pumping blood therefrom when actuated towards said housing, and a second diaphragm coupled to the second ventricle for pumping blood therefrom when actuated towards said housing; and

an actuator of

claim 19

for actuating said first diaphragm and said second diaphragm.

28. A method for storing energy, the method comprising:

arranging a plurality of spaced-apart stationary magnetized segments around a circumference to define a first plurality of spaced-apart gaps, each of the plurality of stationary magnetized segments having a first circumferentially orientated polarity;

arranging a plurality of spaced-apart moveable magnetized segments around the circumference to define a second plurality of spaced-apart gaps, each of the plurality of moveable magnetized segments having a second circumferentially orientated polarity; and

at least one of moving the plurality of moveable magnetized segments between the plurality of stationary magnetized segments and moving the plurality of moveable magnetized segments disposed between the plurality of stationary magnetized segments out of axial alignment with the plurality of stationary magnetized segments.

29. The method of

claim 28

wherein the first circumferentially orientated polarity is the same as the second circumferentially orientated polarity so that the plurality of stationary magnetized segments and the plurality of moveable magnetized segments when aligned within the gaps tend to move away from each other.

30. The method of

claim 28

wherein the first circumferentially orientated polarity is the opposite of the second circumferentially orientated polarity so that said plurality of stationary magnetized segments and said plurality of moveable magnetized segments when aligned within said gaps tend to remain aligned.

31. The method of

claim 28

wherein at least one of the plurality of stationary magnetized segments and plurality of moveable magnetized segments comprises a tapering cross-section.