Artificial joint with locking mechanism

1. An artificial joint for providing pivotal movement between a first body member and a second body member comprising:

(a) a main body;

(b) a lower portion that connects to the first body member and is adapted to pivotally engage the main body about a control axis, the lower portion including a locking means integral therewith which pivots only about the control axis;

(c) an upper portion that connects to the second body member and is adapted to pivotally engage the main body about a flexing axis and having an engagement means adapted to engage and disengage the locking means upon the pivoting rotation of the upper portion relative the main body;

(d) a biasing means adapted to engage both the main body and the lower portion thereby biasing the locking means to engage the engagement means;

(e) at least one stopping surface adapted to limit motion between the main body and the lower portion; and

(f) at least one stopping surface adapted to limit motion of the upper portion;

wherein the locking means is engaged when a load is imposed on the artificial joint that passes through a line posterior to the control axis, and is disengaged when the load passes through a line anterior to the control axis.

2. An artificial joint as claimed in claim 1 wherein the locking means is a latch member.

3. An artificial joint as claimed in claim 2 wherein the engagement means is a step adapted to engage the latch member.

4. An artificial joint as claimed in claim 1 wherein the biasing means is a spring.

5. An artificial joint as claimed in claim 1 wherein the stopping surfaces include a resilient material.

6. An artificial joint as claimed in claim 5 wherein the stopping surfaces are adjustable.

7. An artificial joint as claimed in claim 5 wherein the stopping surfaces are a first stopping surface limiting the motion of the lower portion by its engagement with the main body in a disengaged position and a second stopping surface limiting the motion of the lower portion by its engagement with the main body in an engaged position.

8. An artificial joint as claimed in claim 5 wherein one of the stopping surfaces limits the upper portion when the artificial joint is in a fully extended position.

9. An artificial joint as claimed in claim 1 wherein the artificial joint is used as a prosthetic, orthotic or robotic joint.

10. An artificial joint as claimed in claim 9 wherein the artificial joint is a knee joint.

11. An artificial joint as claimed in claim 10 wherein the lower portion is a shank portion and the upper portion is a thigh portion.

12. An artificial joint as claimed in claim 11 wherein the latch member is positioned at the front of the knee joint.

13. An artificial joint as claimed in claim 11 wherein the latch member is positioned at the rear of the knee joint.

14. An artificial joint as claimed in claim 12 further comprising a swing phase-control means including a piston and cylinder assembly having a first end adapted to engage the upper portion and a second end adapted to engage the lower portion.

15. An artificial joint as claimed in claim 13 further comprising a swing phase-control means including a piston and cylinder assembly having a first end adapted to engage the upper portion and a second end adapted to engage the lower portion or the main body.

16. An artificial joint as claimed in claim 14 wherein the piston and cylinder assembly is hydraulic or pneumatic or a spring.

17. An artificial joint as claimed in claim 15 wherein the piston and cylinder assembly is hydraulic or pneumatic or a spring.

18. An artificial joint as claimed in claim 12 further comprising a manual locking mechanism for over-riding the automatic engagement and disengagement of the locking means.

19. An artificial joint as claimed in claim 13 further comprising a manual locking mechanism for over-riding the automatic engagement and disengagement of the locking means.

20. An artificial joint as claimed in claim 9 wherein the artificial joint is an elbow joint.

21. An artificial joint as claimed in claim 1 , wherein the engaging means engages the locking means without the first body member being fully extended with respect to the second body member.

22. An artificial joint as claimed in claim 1 , wherein the locking means is positioned in the front of the artificial joint.

23. An artificial joint as claimed in claim 1 , wherein the locking means is positioned in the back of the artificial joint.

24. An artificial joint for providing pivotal movement between a first body member and a second body member comprising:

(a) a main body;

(b) a lower portion that connects to the first body member and is adapted to pivotally engage the main body about a control axis, the lower portion including a latch integral therewith which pivots only about the control axis;

(c) an upper portion that connects to the second body member and is adapted to pivotally engage the main body about a flexing axis and having an engagement surface adapted to engage and disengage the latch upon the pivoting rotation of the upper portion relative the main body;

(d) a resilient member adapted to engage both the main body and the lower portion configured to bias the latch to engage the engagement surface;

(e) at least one stop surface adapted to limit motion between the main body and the lower portion; and

(f) at least one stop surface adapted to limit motion of the upper portion;

wherein the latch is engaged when a load is imposed on the artificial joint that passes through a line posterior to the control axis, and is disengaged when the load passes through a line anterior to the control axis.