NOVEL COMPUTER CONTROLLED PROSTHETIC KNEE DEVICE

• US 20070027555A1
• Filed: 07/28/2006
• Published: 02/01/2007
• Est. Priority Date: 07/29/2005
• Status: Active Grant

• Current Assignee: Proteor USA LLC (Holding Proteor SA)
• Original Assignee: Freedom Innovations LLC (Ottobock SE & Co. KGaA)
• Inventors: Palmer, Michael, Bisbee, Charles
• Granted Patent: US 7,655,050 B2
• Time in Patent Office: Days
• US Class Current: 623/24
• CPC Class Codes: A61F 2/642 Polycentric joints, without longitudinal rotation
• CPC Class Codes: A61F 2/70 electrical
• CPC Class Codes: A61F 2/74 fluid , i.e. hydraulic or pneumatic
• CPC Class Codes: A61F 2/741 using powered actuators, e.g. stepper motors or solenoids
• CPC Class Codes: A61F 2/748 Valve systems
• CPC Class Codes: A61F 2002/5006 Dampers, e.g. hydraulic damper
• CPC Class Codes: A61F 2002/704 computer-controlled, e.g. robotic control
• CPC Class Codes: A61F 2002/7635 for measuring force, pressure or mechanical tension

Abstract

A prosthetic knee provides a single axis of rotation and includes a hydraulic damping cylinder, a microprocessor, and sensors. Based on input from the sensors, the microprocessor selects a flow path within the hydraulic cylinder in order to provide the proper amount of knee resistance to bending for a given situation. The resistance of each flow path within the hydraulic cylinder is manually preset. Changes in gait speed are accommodated by employing a hydraulic damper with intelligently designed position sensitive damping. Moreover, the knee need not be un-weighted to transition from the stance phase to the swing phase of gait. As a result, the knee safely provides a natural, energy efficient gait over a range of terrains and gait speeds and is simpler, less costly, and lighter weight than the prior art.

Claims

1. A prosthetic knee system, comprising, in combination:

a frame;

a computer;

a rotor connected to the frame providing at least one axis of rotation about the prosthetic knee and using a hydraulic damping cylinder that compresses or extends to facilitate resistance to rotation, the hydraulic damping cylinder further comprising;

a prosthetic knee flexion resistance path; and

a prosthetic knee extension resistance path;

wherein at least one of the flexion resistance path and the extension resistance path further comprises a plurality of flow resistance paths; and

wherein the computer determines the resistance of the flow resistance path.

2. A prosthetic knee system, comprising, in combination:

a frame;

a computer;

a rotor connected to the frame providing at least one axis of rotation about the prosthetic knee and using a hydraulic damping cylinder to facilitate resistance to rotation, the hydraulic damping cylinder further comprising;

a low force flexion resistance flow path;

a high force flexion resistance flow path; and

an extension resistance flow path, wherein the high force flexion resistance flow path is the knee'"'"'s default and the computer determines when to use the low force flexion resistance flow path.

3. The prosthetic knee of claim 2, wherein in the low force flexion resistance flow path the hydraulic fluid exits the main cylinder chamber and passes through a spool valve into the reservoir having a compressible gas chamber disposed adjacent thereto.

4. The prosthetic knee of claim 3, whereby activating a solenoid allows hydraulic fluid to bypass the high force flexion resistance flow path by effecting the opening of the spool valve for the duration of the low force cycle.

5. The prosthetic knee of claim 4, wherein once the spool valve opens a latching mechanism is triggered, the latching mechanism holding the spool valve opened after the solenoid is deactivated.

6. The prosthetic knee of claim 5, wherein upon a reversal of the hydraulic fluid flow, the latching mechanism releases the spool valve causing the spool valve to close, and a needle valve allows hydraulic fluid to flow through an extension piston bypass resistance flow path into the main hydraulic cylinder, whereby resistance in the extension resistance flow path can be manually adjusted with the needle valve.

7. The prosthetic knee of claim 6, wherein once the spool valve is released, a return spring causes the spool valve to close.

8. The prosthetic knee of claim 6, further comprising one or more check valves that inhibit back flow through the hydraulic fluid flow paths.

9. The prosthetic knee of claim 6, further comprising a computer and sensors, wherein the sensors communicate useful data to the computer.

10. The prosthetic knee of claim 9, wherein the sensors comprise at least:

an extension sensor, the extension sensor communicating useful data to the computer regarding the relative position of the prosthetic knee joint;

a front load sensor, the front load sensor communicating to the computer useful data regarding load on a foot;

a rear load sensor, the rear load sensor communicating to the computer useful data regarding load on the foot.

11. The prosthetic knee of claim 9, wherein the computer regulates damping within the hydraulic damping cylinder, the computer receiving data from the sensors and in response triggering the high force flexion resistance flow path or the low force flexion resistance flow path during flexion of the prosthetic knee.

12. The prosthetic knee of claim 3, wherein the reservoir is separated by a physical bladder forming an adjustable fluid chamber and an adjustable compressible gas chamber, and wherein resistance of the low force flexion resistance flow path is regulated by gas pressure of the compressible gas chamber.

13. The prosthetic knee of claim 3, wherein resistance of the low force flexion resistance flow path is regulated manually by an adjustable needle valve in a low force compression piston bypass resistance flow path.

14. The prosthetic knee of claim 2, wherein the hydraulic damping cylinder is a hydraulic damping cylinder with position sensitive damping.

15. The prosthetic knee of claim 14, wherein the hydraulic damping cylinder minimizes damping during a swing flexion phase of knee movement from about 0 to about 30 degrees and progressively increases damping from about 30 degrees to about 60 degrees,

wherein resistance stops flexion of the prosthetic knee at about 60 degrees.

16. A improved prosthetic knee device comprising:

a computer and a plurality of parallel flow paths of varying flow resistance.

17. The prosthetic knee replacement device of claim 16, wherein the computer selects a flow path based on signals from at least one sensor disposed within a frame of the prosthetic knee.

18. The prosthetic knee replacement device of claim 17, wherein during the stance phase of a gait the computer triggers a high resistance flow path and during the swing phase of the gait the computer triggers a low resistance flow path,

wherein the prosthetic knee remains relatively stiff during the stance phase of the gait allowing the weight of a human to be supported by the prosthetic knee;

and

wherein the prosthetic knee may swing during the swing phase of the gait allowing a lower leg and a foot of the human to advance to the location of the next stance phase.

19. The prosthetic knee replacement device of claim 18 whereby the gait of a human is mimicked.

20. The prosthetic knee replacement device of claim 18, wherein the prosthetic knee remains relatively stiff until after a majority of toe energy is used to propel a human.

21. A method of mimicking a human gait with a computer and sensor disposed in a prosthetic knee comprising, in combination:

providing a prosthetic knee with variable damping,

wherein the variable damping comprising at least;

waiting for a maximum force to be registered in a heel sensor;

waiting for a maximum force to be registered in a toe sensor; and

initiating a second trigger.

22. The method of claim 21, wherein the variable damping further comprises the steps of:

initially triggering a hydraulic damping cylinder to flow a hydraulic fluid through a high resistance path when an extension sensor detects the prosthetic knee to be about straight;

allowing a first period of time to elapse prior to waiting for the maximum force to be registered in the heel sensor; and

waiting for the initiation of a first trigger prior to waiting for a the maximum force to be registered in the toe sensor;

23. The method of claim 21, wherein the maximum force registered in the heel sensor is defined as the minimum value of a moment load, the moment load being calculated by subtracting the value for the load on the heel from the value for load on the toe sensor.

24. The method of claim 21, wherein the second trigger initiates when a moment load, calculated by subtracting the value for the load on the heel from the value for load on the toe sensor, is less than a second triggering value.

25. The method of claim 21, wherein the second trigger initiates after a moment load, calculated by subtracting the value for the load on the heel sensor from the value for load on the toe sensor, exceeds a first minimum value.

26. The method of claim 25, wherein the second trigger initiates after the first minimum moment load value is exceeded and a maximum moment load value is recorded.

27. The method of claim 26, wherein the second trigger initiates after the first minimum moment load value is exceeded, a maximum moment load value is recorded, and the moment load is less than a second triggering value.

28. The method of claim 22, wherein the timing of the initiation of the first trigger and the initiation of the second trigger are modified for descending-type movement when compared to the timing of the initiation of the first trigger value and the initiation of the second trigger value for normal-type movement.

29. The method of claim 21, wherein the second trigger causes the computer to activate a solenoid, the solenoid effecting the opening of a spool valve.

30. A prosthetic knee comprising:

a frame; and

a rotor connected to the frame providing at least one axis of rotation about the prosthetic knee and using a hydraulic damping cylinder with position sensitive damping to facilitate progressive damping.

31. The prosthetic knee of claim 30, wherein the hydraulic damping cylinder minimizes damping during a swing flexion phase of knee movement from about 0 to about 30 degrees and progressively increases damping from about 30 degrees to about 60 degrees,

wherein resistance of the prosthetic knee to stop at about 60 degrees.