6X 775 - 6X 1.625" Drive

Because I don’t design outrageous things enough…

each drive side is 8.03lbs with everything shown (only thing that should be missing is the M4s to mount the 775s. Didn’t design out the full frame because meh.

Ratios is a 12:100 off the 775’s with a 24:24 spacing ratio down to the wheel.
I chained the wheels together before that gear spacing so that the chain did not have to be routed up after every wheel for ground clearance;
so there is a stage of gearing down to each individual wheel.

Feel free to tell me how ridiculous this is.

Sorry for the large pics

http://i.imgur.com/AiMBWJP.jpg

http://i.imgur.com/8TBTTee.jpg

Needs smaller wheels.

Would you consider making custom wheels if they’re that small?

:stuck_out_tongue: :stuck_out_tongue: :stuck_out_tongue: :stuck_out_tongue: :stuck_out_tongue:

Stop being so negative, let him do what he wants

I think you need moar power:p .

What is this I don’t even…

Seriously though, with so little ground clearance, couldn’t this get stuck on something as small as an uneven spot in the carpet?

Also, you missed a golden opportunity to make a 38 wheel (19 wheels x 2 sides) gear-drive. :rolleyes:

1/2" ground clearance, there’s been lower.

Why is there a pox of these going around? This is the 3rd such chassis thingy I’ve seen in the last week.

In any case, looks good. The weight in particular is fantastic. :stuck_out_tongue: The only thing I would question is the use of 775pro drives due to availability and effectiveness, but apart from that it actually looks quite solid.
Why socket heads over buttons or flatheads?
What does the free speed look like?

EDIT: I always look forward to your models. They tend to be very innovative and pretty!

Our 2013 robot had less than 0.25" clearance above the floor and the pan extended forward and behind our wheel base >_>

Yes carpet was an issue. But by comparison this has loads of ground clearance, and even more importantly it has leads in the front and back.

Why use plate and standoff construction only to cantilever the wheels? Is the easier wheel change worth more difficult bumper mounting and greater stress in the structure?

I don’t mean to poke at something that is meant to be slightly whimsical. But if there is a legitimate reasoning, I would just like to know what it is.

Yes, since the wheels have to be replaced between every match :stuck_out_tongue: .

Nick most likely used plates instead of a piece of extrusion because it allowed him to maintain a decent amount of ground clearance. In order to do the same with a tube you’d end up tacking little plates on anyway, so you might as well simplify it.

Such pockets! :slight_smile:

Can we get a render of just the gearbox itself?

I’m also concerned with the gearbox mounting method. Would there be any issues with the fasteners bottoming out on each other before you can get a solid joint?

And talk about all the weight savings on those wheels!

A 775pro drive gearbox could actually be viable. I know team 16 used 775pros for their drivetrain this year and it seemed to hold up really well with the unusual strain from the defenses. When talking to them at Worlds they said there weren’t too many problems and it came down to the gearing. They would be better at describing it.

You’re only a few 10th’s of an inch away from making a polyurethane roller into a wheel. Not that you’d do such a thing.

These tiny Colsons may actually see some wear over the course of 50 matches.

Are you referring to the in-line standoffs? Nick appears to be using the same standoffs-and-set-screws construction method that we used on the dozens of in-line standoffs in our robot’s hood this year. I can assure you that the joints are plenty strong.

Over something like 300-500 matches worth of drive time, a 4" Colson wheel will actually wear enough to negate the drop center in a 6WD. You have to be really abusing these wheels for it to happen, but it does. A 1.625" Colson would wear about 2.5 times faster than that.

Nick: Is this setup actually lighter than a traditional WCD with 3" wheels? With the thicker plate and the gears and stuff, I would be inclined to say probably not.

This is very interesting but I don’t think those little wheels would hold up long unless you added more of them. Ground clearance isn’t the issue with this design at all, our 2013 robot was .250 off the ground and carpet was not an issue even when rolling over the pyramid corner plates.

This is awesome, hilarious, creative, well done, and a lot of other things.

I just have to wonder…

I actually used male/female threads for the 3/4" spacing between the 775 plate and inner-drive plate. This way all the standoffs can remain installed and to take off the motors you just loosen the 4 bolts on the end of that motor plate. I’m not a huge fan of set screws in-between standoffs. I know it can be done effectively but the amount of times I’ve had a set screw vibrate loose between standoffs in VEX has turned me away. This would be a nice set it and forget it setup.

Short answer, no. It might save a little bit of weight but the amount you’d save is not worth all the tradeoffs you’d give up for this. I think trying to use these wheels proved to me there ends up being no benefit.

I debated doubling up the wheels but decided that went against the whole point of the drive, which was to save weight (in theory). Plus you could either double up the wheels to elongate their life an unknown amount, or you could just swap them out every X matches. I’m not convinced I’d go through less wheels if I double up.

Yes, I definitely asked myself if I should… multiple times. Then I remembered it’s July and I had two days off work with nothing better to do, and Bailey and Rahul had already done a solid single speed 775 gearbox, so I figured why bother with something simple like that, might as well have some fun.