Paradoxical gears and Hobson coupling

[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.

Seconded!

[RohanBeckett]

built the hobson's coupling last night..

left it on the kitchen counter, for Mr 5yr old to discover in the morning...

wake up with 'Cooool..... but it sticks a bit... oh.. it's this 6 axle jamming in the hole.. you have to poke it back a bit'

I expect to come home tonight, and find it motorised...

nice to have a little engineer/problem solver in the making!

[pyro690]

That is awesome!

[Kman860]

That is awesome!

+1

[TheWarden]

Are there any pictures or instructions about? I would love to build one to surprise an engineer friend.

I'm non-Technic oriented, but I might be able to make due pausing the video.

[Space Police XVIII]

Okay, these are pretty awesome.

And the music in the Hobson coupling video is annoyingly familiar, can I ask where it's from?

[doug72]

I'm non-Technic oriented, but I might be able to make due pausing the video.

That's how i built my two working copies. The Parox gear one is the hardest to figure out.

[aeh5040]

Wow, I wasn't expecting so much interest - thanks folks! I'll try to do more stuff like this.

Have you tried to apply any considerable torque to the joint - do the axles still run through holes so smoothly?

It wouldn't be suitable for really high torque, because of the long unsupported axles, but with a moderate amount it actually works fine.

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

Yes, it will. As Teuk pointed out, it will even work with flexible connections.

this looks like something Isogawa would build!

Now that is a compliment! Thanks!

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 guess it might be possible to combine several (perhaps larger versions) to make a sort of ball escalator - not easy though...

left it on the kitchen counter, for Mr 5yr old to discover in the morning...

I expect to come home tonight, and find it motorised...

This made my day!

Are there any pictures or instructions about? I would love to build one to surprise an engineer friend.

I'm non-Technic oriented, but I might be able to make due pausing the video.

The intention was that both should be reconstructable from the video. I don't have anything else right now, but if you are having trouble with something specific, just ask...

And the music in the Hobson coupling video is annoyingly familiar, can I ask where it's from?

It was just one of the youtube freebies. It reminds me of the Dubliners version of "Protect and Survive", but I don't think it's actually related!

[Dafgek81]

That Hobsons coupling is so cool, will build something like that soon

[SmeggedAU]

Both look really cool!

[andrewganschow]

I built the hobson by.looking at your video, and after a little bit of playing around, I put a 8 tooth gear on the input shaft then meshed a 40 tooth gear with it driven by a L motor. So now it turns at roughly 850 rpms, and the joint runs smoothly at that speed. No lock ups or skips. I'm still mesmerized by it.

Edited December 5, 2015 by andrewganschow

[Kman860]

I built the hobson by.looking at your video, and after a little bit of playing around, I put a 8 tooth gear on the input shaft then meshed a 40 tooth gear with it driven by a L motor. So now it turns at roughly 850 rpms, and the joint runs smoothly at that speed. No lock ups or skips. I'm still mesmerized by it.

Sounds awesome

[OneMoreRobot]

Nice work, thanks for sharing.

[GI_Jack]

Showed it to my children and we are all amazed

[TechniChriS]

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!

Thanks, I always enjoy your unusual creations.

[Zimix]

That's exactly what lego technic is about, to show how so called simple mechanism do work. Nice work !!

And I really enjoyed to watch it.

[GoldVillage]

TY for sharing, didnt even know that kinda coupling existed!

[Kman860]

TY for sharing, didnt even know that kinda coupling existed!

Me neither

[TheNextLegoDesinger]

TY for sharing, didnt even know that kinda coupling existed!

Me neither

+1

[aeh5040]

That's exactly what lego technic is about, to show how so called simple mechanism do work. Nice work !!

And I really enjoyed to watch it.

Thanks again everyone! I am heartened that such a simple bare-bones presentation of a mechanism has generated so much interest!

[rollermonkey]

Quick poll: how many people watched these and immediately built one or the other?

I broke down sets on my desk to make the Hobson's joint. Very cool.

[doug72]

Have built both of them and added a motor to the hoburn coupling - fascinating to watch

[John Daniels]

I built a bit more compact version of the Hobson coupling. Extraordinarily fun to watch!

[aeh5040]

I built a bit more compact version of the Hobson coupling. Extraordinarily fun to watch!

Please show us!

[Kman860]

I built a bit more compact version of the Hobson coupling. Extraordinarily fun to watch!

Is that even possible?