SELF-ADJUSTING PROSTHETIC ANKLE APPARATUS

• US 20020138153A1
• Filed: 03/23/2001
• Published: 09/26/2002
• Est. Priority Date: 03/23/2001
• Status: Active Grant

• Current Assignee: Hosmer-Dorrance Corp. (Fillauer Cos, Inc.)
• Original Assignee: Globespan Virata, Inc.
• Inventors: Koniuk, Wayne
• Granted Patent: US 6,443,993 B1
• Time in Patent Office: Days
• US Class Current: 623/24
• CPC Class Codes: A61F 2/6607 Ankle joints
• CPC Class Codes: A61F 2/68 Operating or control means
• CPC Class Codes: A61F 2/74 fluid , i.e. hydraulic or pneumatic
• CPC Class Codes: A61F 2002/5003 having damping means, e.g. shock absorbers for implantable joints A61F2002/30563
• CPC Class Codes: A61F 2002/5004 operated by electro- or magnetorheological fluids
• CPC Class Codes: A61F 2002/5018 for adjusting angular orientation
• CPC Class Codes: A61F 2002/6854 for locking or unlocking a joint
• CPC Class Codes: A61F 2002/704 computer-controlled, e.g. robotic control
• 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 auto-adjusting prosthetic ankle apparatus includes a base portion that is pivotally fixed to an attachment portion. The base portion is structured for being fixed to a foot blade, while the attachment portion is structured for fixing the prosthetic ankle apparatus to a lower leg portion of a prosthetic limb. The prosthetic ankle includes a computer controllable damping mechanism that is functionally and mechanically coupled between the base portion and the attachment portion. The damping mechanism enables a damping level to be selectively applied to lightly damp or heavily damp a relative motion between the base portion and the attachment portion as a user is walking to provide an auto-adjusting of the prosthetic ankle to changes in a ground surface being traversed and during various stages of a walking cycle.

Claims

1. An auto-adjusting prosthetic ankle apparatus, comprising:

a) a base portion;

b) an attachment portion for fixing the prosthetic ankle apparatus to a lower leg portion of a prosthetic limb, the attachment portion pivotally fixed to the base portion to enable pivoting of the attachment portion with respect to the base portion, to any position between a first position and a second position;

c) a dynamically controllable damping means structured for functionally coupling between the base portion and the attachment portion, the damping means selectively varying a degree of damping of the pivoting of the base portion with respect to the attachment portion to be one of either a first damping level or a second damping level;

d) a sensing module for detecting when;

i) a pre-selected portion of a prosthetic limb fixed to the attachment portion is in a pre-selected vertical orientation; and

ii) when a prosthetic foot of a user is contacting and not contacting a ground surface;

e) a control means structured for setting the damping means to the first damping level, for a first interval of a walking cycle of a user, and the second damping level for a second interval of the walking cycle as determined by detections of the sensing module.

2. The auto-adjusting ankle in accordance with claim 1, wherein the sensing means includes a level indicating device to determine when a prosthetic limb fixed to the attachment portion is in a pre-selected vertical orientation.

3. The auto-adjusting ankle in accordance with claim 2, wherein the second damping level creates greater resistance to pivoting of the base than the first damping level, wherein the pre-selected portion of the prosthetic limb is a vertical pylon, and wherein the second damping level is enabled when the vertical pylon is plumb.

4. The auto-adjusting ankle in accordance with claim 1, wherein the sensing means includes at least one of:

a) a micro-switch for indicating to the control and computing means when ground contacting is occurring or not occurring, and

b) a load cell installed in the either the attachment portion or a portion of a prosthetic limb fixed thereto; and

wherein the first damping level is selected when the micro-switch indicates that the base has contacted the ground and while the pylon is not vertical.

5. The auto-adjusting ankle in accordance with claim 1, with the dynamically controllable damping means comprising:

a) a hydraulic system having a plurality of hydraulic cylinders, including a first hydraulic cylinder and a second hydraulic cylinder, each hydraulic cylinder structured having a cylinder casing and an associated piston, with each hydraulic cylinder forming an internal pressure chamber;

b) the first hydraulic cylinder positioned in front of the attachment portion, closer to a front portion of an attachable foot blade, while the second hydraulic cylinder is positioned behind the attachment portion, closer to a heel portion of an attachable foot blade;

c) the casing of each respective hydraulic cylinder fixed to the attachment portion so as to pivot and move with the attachment portion, while each respective piston is coupled to the base portion, thereby forcing a first piston to increase a pressure within an associated internal chamber, while a second piston decreases pressure within a second internal chamber; and

d) a transfer conduit arranged to provide a fluid coupling between the internal chamber of the first hydraulic cylinder and the internal chamber of the second hydraulic cylinder;

e) the transfer conduit connecting the internal chambers of the first hydraulic cylinder and second hydraulic cylinder, including a dynamic damping structure, provided to selectively restrict the flow of a fluid flowing from one of the internal chambers in which pressure is increasing into the other of the internal chamber, the damping means operatively coupled to and responsive to the control means.

6. The auto-adjusting ankle in accordance with claim 5, wherein the damping means includes:

a) a magnetic field generating element responsive to the control and computing means for selectively establishing a magnetic field that penetrates the transfer conduit and fluid passing therethrough; and

b) a volume of magnetorheological fluid a portion of which is located within the transfer conduit and influenced by the magnetic field generating element so that when a magnetic field having a first field strength is generated the first damping level is established, and when a magnetic field having a second field strength is generated the second damping level is established.

7. The auto-adjusting ankle in accordance with claim 6, wherein the magnetic field generating element is provided by a magnetic coil that is formed with by coiling of a wire around a magnetically transparent fluid transfer conduit.

8. An auto-adjusting prosthetic ankle apparatus, for attachment to a prosthetic limb having a lower portion, comprising:

a) a base portion structured for fixing to a foot blade;

b) an attachment portion structured for fixing to the lower portion of the prosthetic limb to the ankle apparatus, the attachment portion pivotally mounted to the base portion to enable a foot blade fixed to the base portion to be pivoted to any position, with respect to the attachment portion, between a first position and a second position;

c) a dynamically controllable damping mechanism coupled between the base portion and the attachment portion, the damping mechanism including at least one hydraulic cylinder enabling a level of damping to be changed from a first damping level to a second damping level;

d) a level indicating device for indicating when a longitudinal axis of the attachment portion of the prosthetic limb fixed thereto reaches a vertical orientation; and

e) a control and computing module operatively coupled to the damping means to establish the level of damping selected from a group of damping levels consisting of;

i) a first damping level, and

ii) a second damping level.

9. The auto-adjusting prosthetic ankle in accordance with claim 8, wherein the control and computing module is configured to receive information from the level indicating device and thereby choose between the first damping level and second damping level.

10. The auto-adjusting ankle in accordance with claim 9, wherein the level indicating device is provided by a solid state inclinometer unit.

11. The auto-adjusting prosthetic ankle in accordance with claim 9, with the dynamically controllable damping mechanism comprising:

a) a hydraulic system having a plurality of internal hydraulic pressure chambers, wherein a pivoting motion between the base portion and the attachment portion results in a transfer of fluid between a first internal hydraulic pressure chamber and a second internal hydraulic pressure chamber; and

b) transfer means including a controllable fluid coupling established between the first internal hydraulic pressure chamber and the second internal hydraulic pressure chamber, wherein the controllable fluid coupling, under control of the control and computing module, selectively restricts the flow of a fluid between internal hydraulic pressure chambers, thereby selectively enabling a level of damping to be changed between a first damping level and a second damping level.

12. The auto-adjusting prosthetic ankle in accordance with claim 11, wherein each internal hydraulic pressure chamber is provided in a distinct hydraulic cylinder.

13. The auto-adjusting prosthetic ankle in accordance with claim 12, comprising two hydraulic cylinders.

15. The damping and control apparatus as recited in claim 14, wherein the control and computing module selects the second damping level in response to the level indicating device indicating that the attachment portion is vertical and selects the first damping level when the level indicating device is not vertical.

14. A damping and control apparatus for use with a prosthetic ankle, the damping and control apparatus connected between a base portion and an attachment portion of the prosthetic ankle, wherein the attachment portion is pivotally mounted to the base portion, with the damping and control apparatus enabling the dynamic damping of pivoting motion between the base portion and the attachment portion, the damping and control apparatus comprising:

a) a dynamically controllable damping means functionally coupled between the base portion and the attachment portion, the damping means comprising at least one hydraulic cylinder providing a plurality of internal pressure chambers enabling a level of damping to be changed from a first damping level to a second damping level;

b) a level indicating device for indicating when a longitudinal axis of the attachment portion of a prosthetic limb fixed thereto reaches a pre-selected vertical orientation;

c) a control and computing module operatively coupled to the damping means to establish a level of damping selected from a group of damping levels consisting of;

i) a first damping level, and

ii) a second damping level; and

d) a ground surface contacting device operatively coupled to the control and computing module to indicate when a prosthetic foot of the prosthetic ankle is contacting and not contacting a ground surface.