Quote:
Originally Posted by sdcantrell56
The key to not having cable/rope/whatever jump off a spool is to not use a spool plain and simple. We used 25 chain to drive...
|
You could just use a wide spool and thin cable. That would be much lighter than 25 chain.
We used an aluminum tube (2" diameter, about .030 thick) for our spool, with a sprocket on each end (driven by a banebot transmission/550 each). We used Spectra cable (high strength kite string), which is very VERY strong, light, and very thin (roughtly 1/8" diameter). The spool/drum runs between two sheet metal plates that support the elevator, so the drum is as wide as the elevator (about 20").
We used two 20lb constant force springs for 20lb of total force all the way up, which is actually more than the weight of the carrier assembly. So, if you tip our robot on its side, the elevator begins to go up by itself. We decided it was more important to go up fast than down fast, so we like this. We got our springs from Mcmaster. They are "fun" to work with.