Biomimetic transfemoral knee with gear mesh locking mechanism

Patent metadata

Field	Value
Publication number	US-10864091-B2
Application number	US-201916401886-A
Country	US
Kind code	B2
Filing date	May 2, 2019
Priority date	Nov 2, 2016
Publication date	Dec 15, 2020
Grant date	Dec 15, 2020

Abstract

A prosthetic knee having a passive knee locking mechanism that uses the same four-bar mechanics found in a natural knee. The flexible four-bar mechanism guides the motion of the knee, aids in the return of the knee from full flexion to extension, and connects a femoral gear to a tibial gear. The gears have a circular radius and are connected using parallel links to keep the femur and tibia together when the knee is active. The knee stays locked throughout the stance phase. At toe off, no weight is applied on the prosthetic knee allowing the knee to flex. The flexible links are stretched, thereby increasing the stiffness in the springs, and at terminal swing phase, moments before heel strike, the flexible links in the four-bar mechanism snap back to the extended/locking position and lockout once the user applies his/her weight on the knee.

First claim

What is claimed is:

1. A biomimetic, prosthetic knee apparatus, comprising:
a femoral gear having a curved posterior side with an array of femoral teeth disposed along a bottom side and the curved posterior side of the femoral gear;
a tibial gear having a curved posterior side with an array of tibial teeth disposed along a top side and the curved posterior side of the tibial gear,
wherein the femoral gear is disposed in substantially overlying relation to the tibial gear in an upright position,
wherein the femoral teeth and the tibial teeth engage in a meshable relationship with each other,
wherein the curved posterior side of the femoral gear and the curved posterior side of the tibial gear are aligned with one another, such that the femoral gear and the tibial gear are posteriorly rotatable relative to each other along curved posterior side of the femoral gear and the curved posterior side of the tibial gear, with the femoral teeth and the tibial teeth meshing with each other as the femoral gear and tibial gear rotate relative to each other;
an anterior hard-stop that prevents anterior rotation of the femoral gear or the tibial gear when the femoral gear and the tibial gear are in the upright position; and
one or more ligament links having a first end secured on the femoral gear and a second end secured to the tibial gear, wherein the one or more ligament links has a biased force that facilitates flexion-extension of the femoral gear and the tibial gear relative to each other, the one or more ligament links including:
an ACL link secured to the femoral gear in a posterior position and secured to the tibial gear in an anterior position, such that the ACL link extends in a posterior-to-anterior direction in the upright position of the femoral and tibial gears, and
a PCL link secured to the femoral gear in an anterior position and secured to the tibial gear in a posterior position, such that the PCL link extends in an anterior-to-posterior direction in the upright position of the femoral and tibial gears.

2. A biomimetic, prosthetic knee apparatus as in claim 1 , wherein
a top side of the femoral gear is coupled to a bottom side of a prosthetic femur, such that the femoral gear and the prosthetic femur rotate together,
a bottom side of the tibial gear is coupled to a top side of a prosthetic tibia, such that the tibial gear and the prosthetic tibia rotate together, and
the prosthetic knee apparatus is disposed between the prosthetic femur and the prosthetic tibia.

3. A biomimetic, prosthetic knee apparatus as in claim 1 , wherein each gear of the femoral gear and the tibial gear is substantially semi-circular in shape with linear portions that mesh with each other in the upright position and curved portions that mesh with each other during rotation.

4. A biomimetic, prosthetic knee apparatus as in claim 1 , wherein the anterior hard-stop includes:
an anterior femoral stop extending downwardly along the femoral gear; and
an anterior tibial stop extending upwardly along the tibial gear, wherein the femoral stop prevents anterior rotation of the tibial gear when the femoral stop and the tibial stop abut each other, wherein the femoral stop and the tibial stop abut each other in the upright position.

5. A biomimetic, prosthetic knee apparatus as in claim 1 , wherein
the femoral gear includes two sets of teeth positioned on lateral sides of the knee apparatus,
the tibial gear includes two sets of teeth positioned on the lateral sides of the knee apparatus, and
corresponding femoral and tibial teeth on the lateral sides of the knee apparatus mesh with each other, defining an open space therebetween.

6. A biomimetic, prosthetic knee apparatus as in claim 5 , wherein the ACL link is a first ACL link and the PCL link is a first PCL link, further comprising:
a second ACL link secured to the femoral gear in a posterior position and secured to the tibial gear in an anterior position, such that the second ACL link extends in a posterior-to-anterior direction in the upright position of the femoral and tibial gears, wherein the second ACL link is disposed on a lateral inner surface of a second set of corresponding teeth of the femoral and tibial gears, and
a second PCL link secured to the femoral gear in an anterior position and secured to the tibial gear in a posterior position, such that the second PCL link extends in an anterior-to-posterior direction in the upright position of the femoral and tibial gears, wherein the second PCL link is disposed on a lateral inner surface of the first set of corresponding teeth of the femoral and tibial gears.

7. A biomimetic, prosthetic knee apparatus as in claim 1 , wherein the one or more ligament links includes at least two ligament links, wherein the at least two ligament links operate via a cross-linked four-bar spring mechanism that mimics an ACL and a PCL of a healthy knee.

8. A biomimetic, prosthetic knee apparatus as in claim 1 , wherein the femoral teeth of the femoral gear and the tibial teeth of the tibial gear have a pressure angle of about 14.5°.

9. A passive transfemoral prosthesis, comprising:
a prosthetic femur having a top side and a bottom side, wherein the top side of said prosthetic femur is configured to be coupled to a residual or impaired limb connector in underlying relation to the residual or impaired limb connector;
a prosthetic shank having a top side and a bottom side, wherein the prosthetic shank is rotatable relative to the prosthetic femur, wherein the prosthetic shank is passive;
a prosthetic foot assembly disposed in underlying relation to the prosthetic shank; and
a biomimetic, prosthetic knee apparatus coupled to and disposed between the prosthetic femur and the prosthetic shank, wherein the prosthetic knee apparatus comprises:
a femoral gear having a curved posterior side with an array of femoral teeth disposed along a bottom side and the curved posterior side of the femoral gear,
a tibial gear having a curved posterior side with an array of tibial teeth disposed along a top side and the curved posterior side of the tibial gear,
wherein the femoral gear is disposed in substantially overlying relation to the tibial gear in an upright position,
wherein the femoral teeth and the tibial teeth engage in a meshable relationship with each other,
wherein the curved posterior side of the femoral gear and the curved posterior side of the tibial gear are aligned with one another, such that the femoral gear and the tibial gear are posteriorly rotatable relative to each other along the curved posterior side of the femoral gear and the curved posterior side of the tibial gear with the femoral teeth and the tibial teeth meshing with each other as the femoral gear and tibial gear rotate relative to each other,
an anterior hard-stop that prevents anterior rotation of the femoral gear or the tibial gear when the femoral gear and the tibial gear are in the upright position, and
one or more ligament links having a first end secured on the femoral gear and a second end secured to the tibial gear, wherein the one or more ligament links has a biased force that facilitates flexion-extension of the femoral gear and the tibial gear relative to each other,

wherein each gear of the femoral gear and the tibial gear is substantiality semi-circular in shape with linear portions that mesh with each other in the upright position and curved portions that mesh with each other during rotation.

10. A passive transfemoral prosthesis as in claim 9 , wherein the anterior hard-stop includes:
an anterior femoral stop extending downwardly along the femoral gear; and
an anterior tibial stop extending upwardly along the tibial gear, wherein the femoral stop preven

Assignees

• Ramakrishnan Tyagi
• Reed Kyle B
• Univ South Florida

Inventors

• Ramakrishnan Tyagi
• Reed Kyle B

Classifications

• A61F2/642 Primary

  Polycentric joints, without longitudinal rotation · CPC title

• A61F2002/5073

  Helical springs, e.g. having at least one helical spring · CPC title

• A61F2002/5009

  having two or more elastomeric blocks · CPC title

• A61F2002/5043

  with rotation-limiting stops, e.g. projections or recesses · CPC title

• A61F2002/6836

  Gears specially adapted therefor, e.g. reduction gears · CPC title