pic: 968's 2006 practice bot chassis

[Jonathan Norris]

I agree that this is a very good drive base that has really become the signature for many westcoast teams. But I still wouldn't build one for any of my bots, still don't see any point of exposing my wheels like that... (I know because I saw my team knock two of 254's wheels off in 2005)

[cooker52]

What's that aluminum on the back for?

[Madison]

Originally Posted by cooker52

What's that aluminum on the back for?

It's a roller that helps to keep the chassis from riding up onto balls.

[cooker52]

Thanks.

Did you guys also have another piece to this? I see nuts that look like they're for an expansion.

[Cory]

Originally Posted by cooker52

Thanks.

Did you guys also have another piece to this? I see nuts that look like they're for an expansion.

Yes

http://www.chiefdelphi.com/media/photos/23983

[JesseK]

Eh, the shiny wheels are protected (heh, and covered up) by bumpers nowadays. If I remember correctly, there were no bumpers in 2005. It's still a great solid drive system.

I have to admit I can't figure out how to elegantly mount an AM super shifter to it, but I figure there's still plenty of time to work it out.

Originally Posted by JesseK

Eh, the shiny wheels are protected (heh, and covered up) by bumpers nowadays. If I remember correctly, there were no bumpers in 2005. It's still a great solid drive system.

I have to admit I can't figure out how to elegantly mount an AM super shifter to it, but I figure there's still plenty of time to work it out.

Mounting a SS should be pretty "simple." Just make your own symmetrical side plates, assemble with standoffs, and have two holes designed in that are co linear with the output shaft of the center wheel. Those two holes allow the gearbox to bolt to the chassis member.

[AdamHeard]

Originally Posted by CraigHickman

Mounting a SS should be pretty "simple." Just make your own symmetrical side plates, assemble with standoffs, and have two holes designed in that are co linear with the output shaft of the center wheel. Those two holes allow the gearbox to bolt to the chassis member.

If you line up your cross members right, you can bolt on the SS's without any modification to them (besides longer bolts). 973 did that this year as we didn't have the resources to make our own gearbox plates. I'll take pictures when I can.

[JesseK]

Originally Posted by AdamHeard

If you line up your cross members right, you can bolt on the SS's without any modification to them (besides longer bolts). 973 did that this year as we didn't have the resources to make our own gearbox plates. I'll take pictures when I can.

We did something similar this year with the SS's. We used an exactly dimensioned (with 1/16" tolerance) wooden block with manually CNC'ed holes to represent the SS to get the exact spacing correct while welding. The SS was positioned above the inside frame rail on either side. However, the output shaft wasn't inlined with the middle wheel.

During the design phase it appeared to be more weight to put bearing blocks for direct drive than it was to run more flat AM sprockets & chain, so I went with the 2-chained approach with tensioners directly mounted to the transmission (another bad idea). In hindsight, complexity of maintaining the chain system was what hurt us most this year, so it would have been much more simple to directly drive the middle wheel. We saw 254 & 233's bots in Vegas '07, and saw the simplicity of direct-drive on the middle wheel yet we didn't heed the reasons why. Coulda-shoulda-woulda's aside, maybe it's better we made our mistakes ourselves?

The good news is, we didn't modify our SS's so now we {should} be able to use them again next year if the rules don't change. Now if we could only figure out where this little plastic washer goes on the SS that appeared out of nowhere on our table...

[AdamHeard]

Originally Posted by AdamHeard

If you line up your cross members right, you can bolt on the SS's without any modification to them (besides longer bolts). 973 did that this year as we didn't have the resources to make our own gearbox plates. I'll take pictures when I can.

Pic 1
Pic 2
Pic 3

[team2061]

i could never understand how the wheels stay on. could someone please explain this to me

[Cory]

Originally Posted by team2061

i could never understand how the wheels stay on. could someone please explain this to me

We use snap rings to hold the wheels on.

You can see this here , sort of. There's a groove in the shaft outside the sprocket. The snap ring expands to fit over the shaft, and then contracts when it is seated in the groove, and then keeps the wheels/sprockets from sliding off.

[Cory]

For some reason I can't edit my post. Here's the right link

[team2061]

Originally Posted by Cory

We use snap rings to hold the wheels on.

You can see this here , sort of. There's a groove in the shaft outside the sprocket. The snap ring expands to fit over the shaft, and then contracts when it is seated in the groove, and then keeps the wheels/sprockets from sliding off.

but how is the wheel attached on the other side

[EricH]

Originally Posted by team2061

but how is the wheel attached on the other side

I believe that the sprocket is on the other side. It's a live-axle setup, so the sprocket is attached to the axle via keyway or hex, probably with a setscrew to keep it from sliding sideways.