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Unread 02-01-2012, 22:49
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Re: Simple 2-Speed 6WD for teams with few manufacturing resources

Quote:
Originally Posted by Mk.32 View Post
This may be of some interest.
http://www.andymark.com/product-p/am-0273.htm
Thanks for pointing that out! I didn't know it existed at all.

Quote:
Originally Posted by BrendanB View Post

Are there any major differences in the supershifters over regular shifters?
Is there a reason for the double tensioners on the front chain run?
Any closer pics of the tensioner assembly?
Do you have an estimated speed?
The SuperShifters have a third stage of gear reduction inside that makes them better suited for directly driving wheels. They share many common parts.

The double tensioner was mostly to get the chain away from the floor and offer ground clearance. You could probably use just one in many cases.

See below for speed.

Quote:
Originally Posted by SuperNerd256 View Post
Well that seems kinda low. My 22 fps is definitely wrong, and I've unfortunately lost the paper I used to calculate it (off to clean my room now!).

Madison, is Apalrd right? This looks like one of the best kitbots I've seen, but 10 fps and 3 fps are not my cup of tea. :|
He is right.

Alternatively, you could use the AM Shifter with a 4:1 spread between high and low. This puts it into the 11.7 ft/s and 4.6 ft/s range. That might be more in line with current sensibilities about drive speeds.

It might also be possible to use a 22 tooth sprocket on the Shifter output instead of a 16, but I'm not sure if that'd cause any interference issues. You can't go any smaller than 36 tooth on the wheels, really, because the chain will interfere with the spacers. That maybe isn't as much of a concern with the VexPro wheels as it is with the AM Plaction wheels.

Remember, the intent here is to provide a simple, robust platform for teams to use or reference. Frequently, beggars can't be choosers and so, by minimizing manufacturing complexity, you limit available choices for things like drive ratios.

Quote:
Originally Posted by Feroz1325 View Post
Great design! But I have 1 question.....in your bill of materials, why is there only 1 of the 2 kinds of spacers (1.25 and 2.5)? I count 8 1.25 and 4 2.5?
Thanks for posting!
I believe they're sold in packages of ten.
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