Gearbox selection

[Jared Russell]

The problem with the 2007 BaneBots gearboxes was due to an (apparently) brittle carrier plate. Those with a hardened carrier plate can be identified with "-HC" at the end of their part number sticker. That said, plenty of teams used the gearboxes without any issues that year (especially if you support the end of the shaft with a bearing rather than cantilevering the load).

Other planetary gearboxes that fit the CIM include:
-Banebots P80 series (http://banebots.com/c/P80A-nnnn-n0n5)
(14 reductions between 3:1 and 256:1)

-AndyMark GEM500 (http://andymark.biz/am-0270.html)
(Each level is a 3.67:1 reduction; you can stack as many levels as you want for more reduction)

It's barely different. The casing is a little different sized (bigger, I think?), and it's got some more bolts running along it. Otherwise, the Banebots are excellent gearboxes that have now undergone much more testing than their first forte into FIRST.

That being said: my team is using 4 of the Banebots gearboxes. They're small and reliable, and just the PERFECT speed for us.

[VEI Dude]

Excellent info, thanks. The planetary that banebots is selling now do have the -HC, and I expect to have just a gear on the end, so it sounds like the way to go. I did see/evaluate the P80 and GEM500, but cost is a major issue (plus we'll want to get one spare, so the cost difference multiplies fast).

Craig, are you using single-speed?

Cheers,
-Neil.

[,4lex S.]

I am not so sure that you can use the 2007 KOP BaneBots Gearboxes on a legal 2009 FIRST robot, we looked into it but decided that rule R-32 prohibits this course of action.

<R32>
COTS ITEMS from ROBOTS entered in previous FIRST competitions or COTS MECHANISMS that are no longer commercially available may be used under the following conditions:
B.
The item must not be a part custom made for the FIRST competition and provided in the Kit Of Parts for a previous FIRST Robotics Competition (e.g. 2006 FRC transmissions, custom-made motor couplers, custom sensor strips, 2006 IFI CMUcam II modules, etc. are not permitted),

Its a pain because we have 4 or 5 of them collecting dust... Either way, they are a robust piece of kit (unless you drive them with 2 CIMs each at a huge hunk of Aluminium and smash straight into it repeatedly... ). The P80s look okay and the GEM 500 does too if you can afford them.

[EricH]

Originally Posted by ,4lex S.

I am not so sure that you can use the 2007 KOP BaneBots Gearboxes on a legal 2009 FIRST robot, we looked into it but decided that rule R-32 prohibits this course of action.



Its a pain because we have 4 or 5 of them collecting dust... Either way, they are a robust piece of kit (unless you drive them with 2 CIMs each at a huge hunk of Aluminium and smash straight into it repeatedly... ). The P80s look okay and the GEM 500 does too if you can afford them.

They are a current COTS item, not custom made for FRC. Thus, <R32-B> does not apply.

[VEI Dude]

Yep, my interpretation of R32 is that they also would've had to have been entered in a previous competition, and I found out that we gave them to another team in 2007 (this is my first year with FIRST).

My intention is to purchase from Banebots now, but ,4lex S. if you want to sell yours, let me know.

Cheers,
-Neil.

Originally Posted by VEI Dude

Excellent info, thanks. The planetary that banebots is selling now do have the -HC, and I expect to have just a gear on the end, so it sounds like the way to go. I did see/evaluate the P80 and GEM500, but cost is a major issue (plus we'll want to get one spare, so the cost difference multiplies fast).

Craig, are you using single-speed?

Cheers,
-Neil.

Yeah, I'm doing Single Speed. Though there was a CAD project I did a while back that added a simple 2 speed option to a Banebots... It's a bolt on final stage. If you need multiple speeds, but don't have the space, it's totally doable. (and another hint: Your second "speed" doesn't need to be attached to the wheels, maybe to a winch, or some other mechanism.)

[Akash Rastogi]

I'd second the suggestion for the BaneBots.

We've never had problems with them in our experiences. great boxes.

[,4lex S.]

Originally Posted by EricH

They are a current COTS item, not custom made for FRC. Thus, <R32-B> does not apply.

They may be a current item available at BaneBots, but on the site it says that:

We recently found a few boxes of these - take advantage of our find with a great low closeout price.

In the definition of vendor, FIRST requires:

The VENDOR makes their products available to all FIRST Robotics Competition teams. VENDORS must not limit supply or make a product available to just a limited number of FIRST Robotics Competition teams.

Since BaneBots has a presumably low number of boxes available, I do not think they would be considered a legitimate vendor for this product. No offence intended to BaneBots of course. This does not reflect on the quality of the product, but the availability.

[VEI Dude]

,4lex S., good observation. I have been trying to register on the usfirst forums for a few days now to ask about this to get a definitive answer, but the registration process is failing. Can someone do me a favor and ask this question on those forums, please. Much thanks!

[Nick 568]

Has anyone received a difinitive answer as to if the BB boxes are allowed this year? One design we're thinking of, it would be very convenient to use our 4 BB boxes.

[EricH]

You don't need a forum ID to look at the Q&A.

http://forums.usfirst.org/showthread.php?t=11555

In other words, they better have the hardened carrier plates.

[,4lex S.]

Thanks for that clarification, sorry to introduce any confusion into the matter. The annoying thing for us is that we destroyed half our boxes in competition in '07 and all the parts are mixed together in a box... I really have to get my team on top of that Q and A thing. My apologies.

[Paul11]

Our team used the HC Banebots boxes that came in the kit 2007 and we were very pleased with the performance. They did not break at all and we were not supporting the other end of the axle. If it is allowed I would highly recommend these boxes as they helped our team to the regional semifinals that year.

[VEI Dude]

Well we ended up designing our own gearboxes for the front wheels, with gears from the toughboxes to get the same ratio. So standard toughboxes for the rears, and the re-engineered gearboxes for the front.

The intent was to keep the width of the whole mechanism very small, and with the re-engineered version, I put the motor and output shaft on the same side.

I also used Lexan for the backing plate, and it machines very nicely, though I think it consumes endmills faster. See attached...

Cheers,
-Neil.