The attached picture doesn't show much detail unfortunately, but our climber was about as simple as you could make: We had a single stage elevator we called the "ladder" with about 30" of travel (built very similar to last year's robot). the ladder, which held the hooks, used constant force springs to extend, and a strap winch to retract. At the bottom of the ladder, we installed a
"push to close latch" which held the ladder once it was fully retracted.
The great things about this design were:
- we didn't need to engineer any kind of custom clutch (we don't have much in the way of machining resources)
- the ladder could be reset if the first attempt didn't hook (something you can't do with a ratchet)
- the rigid elevator held the hooks steady when driving up the batter, something a lot of flimsier designs had trouble with.
The result was that we scaled something like 25 times in 26 attempts, something I'm very proud of.
As an aside, we really wanted to use two big 1.5" diameter, 30" travel air cylinders (and about 9 clippard tanks) instead of the winch and latch. The advantage would have been that it was mechanically simpler, and we could climb after the buzzer. Unfortunately the pneumatic version would have been about five pounds heavier than we had allowance for.