Belted Continous In-tube no tube manufacturing elevator

[Eliot]

Well, that was a long title.

Two months ago I had an idea (and a challenge) to make a COTS-compatible belt in-tube elevator.

The main constraint was that teams had to be able to manufacture a continuous elevator with no tube CNC and just a band saw and a vendor kit.

My first iteration revolved around giant billet bearing blocks, which wasn’t workable. (Thank you to @thevedantin for trying to make it workable)

Bearing Blocks

When REV came out with their new clamping bearing block, I decided to make a V2 centered around that design. The bearing block is built with two 3/16" plates, REV clamping bearing blocks, and a 3dp crush block connecting them.

The idler stackup is stolen from @Nick_Coussens. It uses a 19mm od tube as the idler body, with washers on the outside. I elected to go this route rather than use printed pulleys to ensure that they would never fail.

Gearbox

The gearbox is powered by MAXPlanetaries and supports 24-36t pulleys, allowing for a large range of reductions (in inches per revolution):

• 5:1: 1.88-2.83
• 9:1: 1.04-1.57
• 12:1: 0.78-1.18

This ranges from the gearing 8096 used in their 2023 elevator to climb, to the gearing 4414 used in their 2023 elevator to score suuuper fast.

The gearbox is built to support elevator widths between 13" and infinity inches. All you need to do is change the length of the tube connecting it to the idler.

Idler

The redirect idlers go into the tube for strength.

Tensioning

The elevator is tensioned on the top of the carriage with a WCP cam. You would need to drill out some of the holes at the top of this tube for clearance for the bolts.

The belt is secured on the down line by a simple plate. Use a different configuration depending on the width of the carriage.

For the down belt, I had to cut a 1.25" hole out with a hole saw.

I wanted to also have a configurable 3 stage elevator in this document, but I didn’t have the time to make that. Everything needed for infinite stages is in the document, however. In the future, I want to make a new iteration with 0.25" stage gaps and better bearing overlap.

CAD

Thank you to @hanoop, @thevedantin, and @Nick_Coussens (and a lot of other people) for giving me such good feedback on this design!

[Aditya1512]

where did you get the belt?

[Eliot]

I was using this belt:

Elevator Components

Of course, this wasn’t ever built.

[pogobiggestfan]

how long did it take you to build it?

[Eliot]

This elevator was never built, and this version probably never will be built, it was just a fun design exercise.

[pogobiggestfan]

ahhh i see. Sorry, im just trying to get inspirations for the new game

[Giant]

Fantastic work! We had a similar elevator in our 2024 bot, and the change of the in-carriage holder plates both being on the top and bottom is a great change compared to our design, which had that as a notable shortcoming

the question of this image, how do you keep the nautili tight on the vertical parts? Very carefully

[Pep3176]

This is very intriguing, seeing as for a lot of teams a belt-in-tube setup is beyond their manufacturing capabilites. Have you designed any 3-stage elevators that keep the belt-in-tube design? Could be useful this season to reach height. Very impressive design!

[Eliot]

These bearing blocks can very easily be put in more tubes to reach another stage. All you have to do is copy the design of the first moving stage again. You also might want to change the bottom belt holder to the other configuration.

[Eliot]

It looks like a few people are actually planning to build this elevator, which I was not expecting. I have a few notes for anyone planning to make this:

In tube plates

Tube tolerances aren’t exact, so the internal dimensions of them aren’t exact. REV lists theirs as 0.06", which works for these plates. Just know, if you have slightly oversized tubes you may need to file the plates down.

Tapping

A 2 stage elevator requires 48 tapped holes. That will probably take a lot of time. You can get fabworks or send cut send to do it for you, but that adds a ton of additional cost.

Idler Shaft

This shaft can either be 8mm or 5/16" in diameter, and should be cut down to 2".

Elevator blocks

This needs the REV elevator blocks (or a lot of facing operations on the WCP one). They are currently out of stock. REV’s website says that they should be in stock by the end of January.

Belt retention

If you’re using an elevator that isn’t the exact width of my example one, you should use this bottom belt holder, not the other configuration.

I’ve never built this

While I think the mechanical design is sound, I have never built this in real life, and neither has anyone else. I haven’t had anyone find and point out mechanical problems to me, but that doesn’t mean that they aren’t there. If you’re building this, you might want to budget some time to fixing issues as they pop up. If you find any issues, PLEASE tell me.