I feel a bit embarrassed posting these given some of the amazing creations we've seen recently, but here are a couple of little mechanisms. Neither is original as a concept, but the LEGO implementations are new. Enjoy!

Paradoxical gears: turn in the same direction!

Hobson's constant-velocity right-angle joint:

That right angle joint is freaking me out. Doesn't seem like it should work, but it obviously does. I had to stare at the gears for a while as well to understand why they rotate the same direction.

That right angle joint is freaking me out. Doesn't seem like it should work, but it obviously does. I had to stare at the gears for a while as well to understand why they rotate the same direction.

Yes I agree! I had to make LEGO versions of these things to understand how they work...

Those mechanisms are really great, I especially like the angle joint, it reallly looks like it shouldn't work. Have you tried to apply any considerable torque to the joint - do the axles still run through holes so smoothly?

Have to build those. Very interesting.

These really freak me out too!!!! Amazing stuff!!Had to google them...there is always so much to learn!! I'm wordering where instaed of a 90 degrees connector we could use a U joint to achieve different angles....therefore this could be used on a front axle for turning wheels??

That right angle joint is just amazing! I was very skeptical before playing the video but it definitely convinced me. I have to build it!

Nice builds!

I really like the paradoxical gears, these are facinating.

And for those who are wondering, Hobson's joint can work with any angle, and a variable one too, as seen here : http://www.techlug.fr/Forum/post70952.html#p70952

It is sometimes used in the industry, but other cheaper cv joints are usually use, although hobson's joint has the largest range of angles, from around 30° to 180°

I don't think I can think for the rest of the day! My brain is fried!

Well done. These vidoes really are quite hypnotic... They would make for an awesome .gif!

Yup, that Hobson mechanism looks quite baffling at first look, and mainly because it's not a frequently seen thing, yet is seems so straightforward. I graduated as a mechanical engineer, but we weren't taught about it. But if you look closely, the principle is very simple. At any arbitrary time, the bent axles on the outer and inner side of the coupling are simply pushed up and down. The bent axles on the top and bottom do nothing to rotate the output wheel. Maybe the ones that are on the top and bottom draw attention more that the others, and that's causing the confusion.

I guess this mechanism requires very good bearing of the bent axles to be efficient.

Edited December 2, 20159 yr by Lipko

I'm still trying to understand how the paradox gears are connected....

Using the videos as a guide have built both of these, took awhile to get the Paradox one to work.

The Hobson coupling isi facinating to watch.

Do you think that right angle Hobson joint would work with red #3 connectors as well?

Wow very interesting :thumbup: .

Do you think that right angle Hobson joint would work with red #3 connectors as well?

It should as long as you support both ends

Nice!

Do you think that right angle Hobson joint would work with red #3 connectors as well?

This will be fascinating if many of couplings are chained in one large machine. But only red #3 connectors will do the job)

Very cool! I saw these a few days ago, so I can understand how they all work, but they're really cool none the less

this looks like something Isogawa would build!

might try to use it in a GBC or something - even if it's 'just for show' (which, technically, what most GBC's are!)

might try to use it in a GBC or something - even if it's 'just for show' (which, technically, what most GBC's are!)

I was thinking the same thing while watching the videos.

Still can't figure out the paradox gears...

Still can't figure out the paradox gears...

Think of it as a series of shaped levers with the ones on the input axle pushing those on the driven axle..

Think of it as a series of shaped levers with the ones on the input axle pushing those on the driven axle..

I kind of get it now

Edit: just watched it again, and looked closer at the position of the second gear "teeth", I understand it now.

Edited December 3, 20159 yr by Kman860

That right angle joint is freaking me out. Doesn't seem like it should work, but it obviously does. I had to stare at the gears for a while as well to understand why they rotate the same direction.

I agree!