Suitable knee joint assembly

Let's Make Robots Project Ideas
1

Hello,

My son has a major project due in a few months to do with basic unpowered exo-skeleton systems. As life would have it, being his father and an experienced metal fabricator (I made reproduction Medieval armour) I am left doing the digging and allot of the research :rolleyes:

I think I have it pretty much all in order except for the elbow & knee joints. I am trying desperately to get a name for a suitable type of joint to fit the bill. To that end I have photo-shopped a couple of Hyme joints together to give you a sense of what I am trying to find.

There would be a 1” aluminum rod running down the leg from the hips to the upper knee, and again from the upper knee to the foot pad… to connect these with the proper range of motion. Basically I guess what I am describing is a self-encased knee joint, that all I need do is insert and secure the longer extension (synthetic leg bones) rods into. So it would function as an actual rotational knee section.

Any suggestions? Anybody know where to pick these up etc???

Thanks in advance for any help offerred!

Phillip

2

Where did you get the image of the middle one?
What is it in everyday life and I wonder who manufactures them?

I was talking to a Bearing guy about the nature of the hyme joint and he mentioned that it wasn’t actually designed to be a rotational joint, only an interface for 2 slightly out of position components.
But in a pinch, I guess a Hyme joint and its male counterpart threaded through the top hole might work.

3

Hi Phili,

Welcome to the RobotShop forum. Why not use a simple U-tube with a through-hole to connect to the hyme joint? Since the system is not powered, and the lengths are not variable, having material on either side of the joint would ensure it moves only in one direction. Look up “U joint”.
Some ideas:

http://tbn0.google.com/images?q=tbn:4rgRxOSPlVKDoM:http://www.ppo.co.uk/pelham/info/identification/images/knees/knee-metal-joint.jpghttp://tbn0.google.com/images?q=tbn:FKsD7zLqKKEMDM:http://handicappedpets.comhttp://tbn0.google.com/images?q=tbn:iIcP7zQtedPLlM:http://www.fiatforum.com/gallery/data/616/1407new_1.JPG

4

The middle image is an orthodic knee brace for animals. You can find more information here. A search for artificial joints or mechanical hinges might help. If you can weld, you should have no problems at all. :smiley: