Drivetrains beyond the KOP

[twolf]

Obviously when you attend a regional you see the teams that have been at this for a long time that have very non traditional drivetrains that might be skid steer, tank tracks or whatever else. We are wanting to acquire some of these components to test them for next year so we can move beyond the casters and pneumatic tires. Is there a good site to buy this stuff? I have checked out AndyMark and we used their Omni wheels this year.

Also, do you have to use the kit transmissions? Are the AndyMark transmissions the same as the KOP?

Please help if you can, we really want to move up a level for next year.

[Jeff K.]

You are not required to use the KOP drivetrain.
I think the only thing we used from the KOP for drive this year were the master links.
You can design your own gearboxes and whatever, just as long as it's within weight and budget.

[Billfred]

Originally Posted by twolf

Obviously when you attend a regional you see the teams that have been at this for a long time that have very non traditional drivetrains that might be skid steer, tank tracks or whatever else. We are wanting to acquire some of these components to test them for next year so we can move beyond the casters and pneumatic tires. Is there a good site to buy this stuff? I have checked out AndyMark and we used their Omni wheels this year.

Also, do you have to use the kit transmissions? Are the AndyMark transmissions the same as the KOP?

Please help if you can, we really want to move up a level for next year.

Well, there's a few good suppliers out there--many of the tank treads are sourced from Brecoflex. They're expensive and slow, but yield good results (see also: recent SPAM).

There's also a lot of good sources for parts in this thread.

The kit transmissions are good, but entirely optional. The AM Shifter is an entirely different two-speed pneumatically-shifted transmission (although I recall that 343 has successfully modified them to shift with servos). The AM Gearbox has the same gear reduction as the KOP Transmission, but a different output shaft (1/2" versus around 5/8" for the Kit).

There's also the option of rolling your own transmission--there's several designs in the white papers section of CD-Media. Anything that meets the rules set forth in the FRC manual is fair game.

[sanddrag]

I'm glad you have taken interest in going beyond the kit. Next year's rules have not yet been released, but in the recent past, there has never been a requirement to use the kit-supplied gearboxes and it is not likely there will be.

AndyMark makes a single speed gearbox quite similar to the kit-provided gearbox but it has slightly different dimensions and mounting I believe. Their shifter gearbox is a whole different beast.

Some good sites for gears and other components (bearings, etc) in no particular order are:
www.bostongear.com
www.wm-berg.com
www.mcmaster.com
www.smallparts.com
www.motionindustries.com
www.sdp-si.com

A common size of gear used in custom FRC gearboxes is 20 pitch, 14.5 degree pressure angle, 3/8" face width.

Here's our 2005 transmission and here's our 2006 transmission.

If you have some more specific questions I'd be happy to provide some more specific answers.

[Gene F]

Originally Posted by sanddrag

Some good sites for gears and other components (bearings, etc) in no particular order are:
www.bostongear.com
www.wm-berg.com
www.mcmaster.com
www.smallparts.com
www.motionindustries.com
www.sdp-si.com

Add http://www.martinsprocket.com/ to this list. We (Team 343) have used their gears for the last several years and they are very fond of FIRST!

[lukevanoort]

www.robotmarketplace.com has a lot of random robot related stuff. A lot of it isn't FIRST legal, but it's always worth a browse. This whitepaper has great explanations of the various types of drivetrains, for dog shifting gearbox design the whitepaper on 188's '04 design is excellent, the whitepaper on the Killer Bees' four speed is also excellent, if you're into something different the whitepaper on the Tigertrons three speed ball shifter is also quite good, and for cheap, simple, and light multispeed gearboxes, it's hard to beat the DeWalt XRP transmission, the use of which is detailed in the NBD whitepaper. (Although the Killer Bees four speed really gives the XRP three-speed a run for its money)