AndyMark Stackerbox

[AdamHeard]

Originally Posted by Andy Baker

You guys are good.

A version of this idea was proposed to me from mentor Mike Koch from team 1720 in Muncie, in mid-November. I took a week or two to make a nice design, then got parts quoted and sourced. We are finishing up the build on a production run of these gearboxes. Mike does not know this, but his team will get a couple of these for free.

(by the way... this is one of the things I LOOOOOOVE about being a small business: you can act quickly on an idea)

It's not a gearbox that will be in the 08 Kit of Parts. Even so, it's a neat-o gearbox. I'll explain:

Gearbox type: spur gear reduction, one stage
Gearbox Size: 5" x 3" x 1" wide
Reduction: 3.57:1 (14 tooth gear driving a 50 tooth gear)
Shafts (input & output, identical): 3/8" dia w/ 3/32 keyway, sticking out 1" from side of gearbox
Gears: 20 dp, 14.5 pa steel gears w/ ~ 3/8" face width

No motor mounts.

To use this gearbox, you would connect something (sprocket, hub, pulley) to the input shaft (3/8" dia) and drive it. You would then get a 3.57:1 reduction out the output shaft.

The cool thing is... and here's where it gets its name... you can stack 2-3-4-5 of these things back to back and keep multiplying a 3.57:1 ratio to your output shaft. These are a large, spur gear version of what Chuck (deepwater) posted above.

And... another thing (and this will take a bit longer), we can vary the reduction inside the gearbox by replacing the two gears with any two of the same dp and pa, as long as the teeth add up to 64. We're working on other ratios, but for now the only one that will be available by the end of the year is the 50:14 ratio.

Yes, Andy B and Scott (indysam).... put two of these on top of each other, and you have a nice reduction for an arm.

I'll post some CAD pics on the site tomorrow. I suppose that we better assign a price to this thing too. Where's that dartboard?

There are many new little parts coming out within the next few weeks. Good find, Burchardt.

Andy Baker

What is the weight on them?

Also, is it housed in 5 x 3 extrusion similar to the single speed/ super shifter?

[Andy Baker]

Originally Posted by AdamHeard

What is the weight on them?

Also, is it housed in 5 x 3 extrusion similar to the single speed/ super shifter?

The extrusion is different, but the same overall width. This gearbox uses smaller screws (#10-32). The extrusion wall thickness is 1/8". The hole pattern is different, and is not meant to match up with the AM Gearbox or Super Shifter. The side plates are 1/4" polycarbonate. It will be light. My guess is that it will be about 1.5 lbs... maybe less.

Due to the speed needed of development combined with the simple design, we did not make a prototype. We went straight to production from CAD. We'll see if this risk turns out well.

Andy

[dtengineering]

Originally Posted by Andy Baker

Due to the speed needed of development combined with the simple design, we did not make a prototype. We went straight to production from CAD. We'll see if this risk turns out well.

Andy

Well, just make sure all the stuff that is supposed to be hard is hardened, and you'll have no problems. Your stuff has always worked great!

This is a great idea... it lets us mount heavy motors down low, and have relatively low tension in the chain/pulley that leads up to the gearbox at the shoulder... or where ever. Just the other day I was looking at worm drives to run a shoulder joint and thinking how helpful an off-the-shelf solution in the right size and weight range would be.

Hmm... about the only thing I'd ask for now is for it to have an encoder or potentiometer mount built into the output shaft, and for an integrated brake mechanism to lock it in place.

Not that we can't take care of those items ourselves, of course.

Jason

[s_forbes]

Since the input gear is the same as the one on the AM singlespeeds, it should be pretty easy to convert one to accept a small CIM. Maybe you could manufacture a simple conversion plate for this...

It's funny, just a couple of weeks ago I was trying to think of the easiest way to remove one of the reductions from the AM singlespeed!

[Andy Baker]

Originally Posted by s_forbes

Since the input gear is the same as the one on the AM singlespeeds, it should be pretty easy to convert one to accept a small CIM. Maybe you could manufacture a simple conversion plate for this...

Hmm...

This is another good idea. I will look into it.

AB

[MrForbes]

Don't encourage him, he's supposed to be studying for finals!

[AndyB]

I'm stunned. What a brilliant idea. No to tell you the truth, I was just looking for models for the AM Single Speed and ran across it. Screw getting my new year's kiss, I'm gonna wait on AndyMark.

I like the idea of the stacking planetaries though as well... maybe Andy has plans for that down the road as well.

Dude. This is awesome! I have a feeling you'll start seeing AM parts on 114 sometime soon... The quality has been going up and up, and I'm really quite impressed with the stuff you guys are rolling out.

A gearbox that is stackable makes a great arm setup. Sweet!