Chain-driven 5+R Gearbox

[2GodBDGlory]

After finally getting a couple of the new spur 20T clutch gears, I was struck with an idea for a new gearbox setup I could make, making use of their ability to drive chains. Because of this, and the new 12T and 20T spur gears, there's actually a lot of options for gearing, which can be done in a straight line, much like a real car's gearbox.

I built two versions of this gearbox, which were a bigger 5+R gearbox, with these gears:

R: 20:28, direct drive rather than chain

1: 20:24

2: 20:20

3: 20:16

4: 20:14

5: 20:12

By nature, this gearbox is very close range, and the fact that I used the old and chain-capable 14T gear to get a fifth speed makes some speed changes extremely small. Additionally, doing six positions with the wave selectors is tricky. I did it by offsetting them by connecting them all to another axle beside it with 12:20 gearing, which, because 12 is divisible by 3, allowed me to space three of them apart evenly, making only one ring engaged at once.

Because of these reasons, and its size, I figured that most people wouldn't be interested in using it, so I also built a much more basic 4-speed version, with 20:24, 20:20, 20:16, and 20:12 gears and a straightforward wave selector setup. Unfortunately, I took it apart last night after it had been sitting on the shelf for a while, and only just now realized that I didn't take any videos of it... It should be pretty easy to figure out how it would have looked based on this 5+R one, though.

I'm not sure how the chain would hold up to heavy use, but it is a refreshingly straightforward way to get lots of speeds in a Lego transmission!

By the way, I only had two of these gears from Lego, so I had to 3D print the other four. It still worked fine!

Edited April 23, 2023 by 2GodBDGlory

[aFrInaTi0n]

Nice gearbox!

Chainlinks can handle more torque when put on inside out. Can be observed here:

 

[2GodBDGlory]

Good to know! I seem to remember The Unofficial Lego Technic Builder's Guide suggesting the opposite, but those tests look convincing, and make sense to me, so I'll change my practice.

[Aleh]

Wow, something new! Will investigate how it works!

[1963maniac]

This is very interesting. I would like to build it so I can try it myself. Are there any instructions for it?

[2GodBDGlory]

38 minutes ago, 1963maniac said:

This is very interesting. I would like to build it so I can try it myself. Are there any instructions for it?

No, sorry. If you have specific questions about something I can answer I'd be happy to help, but I think the working principle is simple enough to copy