How are y’all staying up on the chain after the robots are the disabled after the robots are deactivated? My team wants to use ratchet plates on our gear box but then we cannot lower the climb to get on the chain. So I just wanted to know what others were doing.
Unless your climber has two motors and is geared way down, break mode probably won’t be able to hold you up consistently.
We are only 85 lbs, and a vortex with a 25:1 ratio, and break mode was only holding off the ground for 4 seconds. So we decided to add a latch when it reached full retraction, and not only does it hold us just fine, but it means we can gear the climber to be faster.
The latch specifically triggers when the chain is pulled into it, so unless we’ve grabbed the chain, we can go up and down all we want the rest of the match.
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You can use constant force springs to pull your climber down passively, all the time. The motor would be working against the springs on the way up, but would be aided by the springs on the way down to lift the robot up. After match ends and robot is disabled, your motor’s brake mode + the constant force spring will hold the robot up if you size the spring properly. The spring you choose would depending on how much your robot weighs and what your climber gear ratio is.
Another option is to implement a pneumatic friction brake (WCP sells these) in your climber gearbox. Friction Brake & Ratchet – WestCoast Products
It works well with their Rotation SS Gearbox. But of course it requires a pneumatic circuit, which may not be part of your team’s plan. WCP Rotation SS Gearbox – WestCoast Products
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We use one of these motors. Worm gear inside prevents back-drive innately.
Works like a charm. Entire climb takes maybe 5 seconds?
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You could also just increase your gear ratio in the existing setup to make the robot come down more slowly. This is probably the easiest option to implement. Do you have any higher ratio cartidges, or spares of any ratio? If not I think they’re in stock REV Robotics
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We are using 2, 2 stage AM climber-in-a-boxes with neo’s and a 20:1 MP. The robot is about 4 inches off the ground when the climbers are fully retracted, and, using only brake mode, we do not begin to touch the ground for over 15 seconds when on the lowest point on the chain. Although they are not the fastest things ever, the climbers only have to move a very small amount to lift the robot. This means that even on 20:1 we are still able to complete our climb in a fraction of a second.
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We could have, but our cycle time is pretty fast, so we’re hoping to keep scoring until the last second, so we need a fast climb. At 25:1 the speed was already pretty underwhelming, so we opted for a 15:1 off the Vortex and already have a latching mechanism on it that works well.
A question I had after misreading this title - but do the rules explicitly rule out post match climbs this year? Feels like it could be advantageous for a fast cycler.
Scores are finalized either 5 seconds after the match or whenever movement stops, whichever comes first. If you’re able to have a mechanism that lifts you off the ground before t+5 seconds comes there’s nothing that explicitly disallows it.
It’s… a tad bit more nuanced than that. I’ll add in the relevant rules once I get home. Starting a climb right up to T=0 and finishing before T=+5s is generally fine… but there are ways to bend and break that, and those are Right Out.
Relevant rule: G212, item F in the Blue Box–basically as long as you’re in compliance with all other rules, you’re fine. But if you somehow have a mechanism that violates the rules within the 5-second “come-to-rest” time, it’s pretty bad for you.
FMS ( the Field Management System) kills all the motors at the end of the match. To keep climbing after, you’re going to need to use stored energy - spring, pneumatic door closer, ….
This has been done before. It exploited the fact that the 2022 rules limited maximum robot height to less than the height of the top rung, but only during the match, and climbs weren’t scored until 5 seconds after the match.
edit: first described at the bottom of this post
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And was promptly–and permanently–banned.
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Very interested in this latch mechanism you are mentioning 
2491 is using a worm gear to keep our robot from lowering when we do want it to.
A method to climb while only spinning the spool 1 direction is to use constant force springs. This allows you to start spooled up (climber down) then as you unspool the climber will be lifted by the springs, and then you keep unspooling until you are empty and it will start spooling the other direction and pull the climber.
This method only spins the spool 1 directiin and allows you to use a ratchet.
Hook brings the chain down, the latches on the non-moving stage of the elevator are spring loaded and rotate out of the way when the chain is pushed down into it, then once the chain is past the latch, it snaps back over it, and holds it from going back up.
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I’ve seen teams use a ratchet wrench to keep a climber from unwinding from gravity. The climb motor winches the ‘bot up while rotating the ratchet; when power’s off the ratchet holds. To lower the bot you need to lift the ‘bot to unweight the ratchet, then flip the lever on the wrench to let it unwind.
Note: you must attach the ratchet handle very securely to the ‘bot.
Years ago, in the pits, a student was injured when the ratchet handle broke loose from the frame of the ‘bot. It was held only by plastic zip-ties. It must be attached by stronger metal fittings.
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