TORQUE MEASURING SPRING FOR A PROSTHETIC DRIVE

• US 20190321200A1
• Filed: 07/01/2019
• Published: 10/24/2019
• Est. Priority Date: 09/03/2017
• Status: Active Grant

• Current Assignee: Otto Bock HealthCare LP (Nader Holding GmbH & Co. KG)
• Original Assignee: Otto Bock HealthCare North America Incorporated (Nader Holding GmbH & Co. KG)
• Inventors: Smith, Weston, Morse, Christopher, Balutis, Paul
• Granted Patent: US 11,109,986 B2
• Time in Patent Office: Days
• CPC Class Codes: A61F 2/66 Feet; Ankle joints
• CPC Class Codes: A61F 2/68 Operating or control means
• CPC Class Codes: A61F 2/76 Means for assembling, fitting or testing prostheses, e.g. for measuring or balancing, e.g. alignment means
• CPC Class Codes: A61F 2002/5003 having damping means, e.g. shock absorbers for implantable joints A61F2002/30563
• CPC Class Codes: A61F 2002/5033 for adjusting damping damping means A61F2002/5003
• CPC Class Codes: A61F 2002/5072 having spring elements spring-biased locking means A61F2002/30505; for implantable joints A61F2002/30565; other elastic means A61F2002/5007
• CPC Class Codes: A61F 2002/5087 Sound-damping or noise-reducing means
• CPC Class Codes: A61F 2002/607 Lower legs
• CPC Class Codes: A61F 2002/7625 for measuring angular position
• CPC Class Codes: A61F 2002/7635 for measuring force, pressure or mechanical tension

Abstract

An improvement to a prosthetic device which provides a spring member between first and second structural members that are rotatably connected to one another, the spring member providing predictable resistance as it is compressed by the rotation of the first and second structural members with respect to each other. The known resistance of the spring is used as an input to a model controlling a motor control circuit to provide counter-torque as rotational torque is applied to compress the spring.

Claims

1. A prosthetic, orthotic, or exoskeletal (POE) device comprising:

a first member;

a second member moveably connected to the first member; and

a spring member fixed to the first member, the second member contacting the spring member during at least a portion of the movement of the second member with respect to the first member, the spring member deflecting from a neutral position when contacted by the second member and providing resistance to the rotation of the second member.

2. The POE device of claim 1, further comprising a contact plate located between the spring member and the second member.

3. The POE device of claim 2, wherein the contact plate is attached to the spring member at a point of contact between the spring member and the second member.

4. The POE device of claim 2, wherein the contact plate is attached to the second member at a point of contact between the spring member and the second member.

5. The POE device of claim 4 wherein the contact face is composed of a thermoplastic compound.

6. The POE device of claim 5 wherein the thermoplastic compound is acetal homopolymer.

7. The POE device of claim 1, wherein the deformation of the spring member between the neutral position and the hard stop is approximately linear.

8. The POE device of claim 1 further comprising a hard stop, fixed to the first member, the hard stop limiting the deflection of the spring member and the rotation of the second member.

9. The POE device of claim 6, wherein the spring member deflects less than 1 mm before contacting the hard stop.

10. The POE device of claim 1 wherein the second member and first member have a rotational motion between 5 and 10 degrees with respect to each other before the second member contacts the spring member.

11. The POE device of claim 1, wherein the spring member is attached on one side of the first member, the apparatus further comprising a second spring member attached to the opposite side of the first member.

12. The POE device of claim 1 wherein the spring member comprises:

a first arm;

a second arm connected to the first arm;

a third arm connected to the second arm;

a fourth arm connected to the third arm; and

a mounting plate, connected to the fourth arm;

wherein the first arm and third arm extend along axes which are substantially parallel to each other, and wherein the second arm in the fourth arm extend along axes which are substantially parallel to each other.

13. The POE device of claim 12 wherein:

the second arm connects to the first arm at a substantially 90°

angle;

the third arm connects to the second arm at a substantially 90°

angle; and

the fourth arm connects to the third arm at a substantially 90°

angle.

14. The POE device of claim 1, wherein the spring member is connected to the first member via the mounting plate.

15. The POE device of claim 1 wherein the spring member is composed of titanium;

16. A method comprising:

providing a POE device according to claim 1; and

causing the second member to move with respect to the first member and contact the spring member, the movement deflecting the spring member from the neutral position.

17. The method of claim 16, further comprising:

measuring an angle between the first member and the second member;

providing the measured angle to a model for controlling an actuator control circuit; and

controlling the actuator based on an output of the model to apply torque to a pivot point between the first member and the second member.

18. The method of claim 16, wherein the deflection of the spring member from the neutral position is approximately linear between the neutral position and a hard stop.

19. The method of claim 16, further comprising attaching the first member to a leg of an amputee.

20. A prosthetic joint providing powered joint extension or flexion, wherein a moment applied to the joint is determined by a component that displaces when subjected to a load applied to the joint.