Magnetic Effector Idea

I really like the idea of using magnetic connections for my custom delta build. I notice how much play there is within each Traxxas 5347 joint I'm presently using and don't like the idea of using springs or bands to compress the arms.

Here's my idea, and I'm not certain if it's already been done, so please excuse me if it has! Rather than placing the magnets at the end of each arm, we could embed the magnets within the effector design itself, sharing the magnets with adjacent nubs.

Here's a quick mockup:
Thingiverse Mockup

A couple of little problems are coming to mind, though the concept looks interesting.

The first thing that comes to mind, looking over your screenshots is the design, the way it is shown, has the magnetic cylinders positioned vertically. This would mean that the steel balls fitting inside the cups would be relying on the magnetic forces from the sides, between the poles where they are weaker, and not from the poles themselves where the field is it's strongest. The second thing I see after downloading your model and applying transparency to it is there looks to be space (around 2mm?) between the magnet and the cup for the ball. The pull of the magnetic field falls off almost exponentially with increasing distance. Turning the magnet on its side and allowing it to directly contact the ball would make a lot of difference in how secure the connection would be. I would think it would cut down on the mass a bit. Same number of balls, half the magnets.

Mark

I like AndyCart's idea from the Cherry Pi to use spherical magnets on the effector plate, and cup socket (allen) drive cap screws with a ball end mill bit for the rod ends. There's a few posts in the comments section of his Cherry Pi Thingiverse page about te different ball/socket/magnet combinations that he tried and which ones work best.....