our team has never been able to climb and are wondering how other teams have set up there elevator to have enough power to climb. and also how other teams get there elevator to hold there robot there when the match ends
My team climbed with our elevator and used a pnuematic + spring actuated ratchet and pawl in 2018.
Not sure if elevator is the way to go for 2020 though.
Regardless of the type of mechanical structure used to attach to the rung or to get your hook onto the rung, you need to generate sufficient force to lift your robot in the time desired. It would be very beneficial for you to learn to use the “JVN calculator” to ensure that your mechanism generates sufficient lifting force under all foreseeable conditions and with adequate margin.
If you are going to use a pneumatic powered solution, you will have to use other methods to ensure that you generate sufficient lifting forces.
We can climb in the past we have used screw drive/scissor Stronghold, Frayed ends two CIM in Steamworks, Two large hooks on our elevator in PowerUP driven by a triangle Chain drive …the key is build it robustly and power it well.
All those methods worked . Probably wont do scissor again though it was it compact though for the low bar sort of a pain, we would set a hook and it was attached by a slot instead of a hole , so the scissor mechanism could collapse after the hook was set then winch up.
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Can you post some videos of your robot with these different mechanisms?
2018 This was a good one we knew our mechanism was solid when only the end of the hook pulled us up in another match just one fingertip hook pulled us up the hooks were robust… 5137 Blue https://youtu.be/EzrHkH1_KeE
2017 RED https://youtu.be/mzWzs70gtHg using frayed/whipped ends to hook tape
The driver just cycles the lift motor to stay up could not find a video of the scissor lift .
Your lift worked very well. Did you use #35 chain? In steamworks we used a mini toughbox with a shaft to grab the frayed rope. It worked well and had power, but we were thinking more of a single stage lift with hooks on the top. What kind of bearings did you use to keep your lift in line. We have used 80/20 with linear motion slides and Rev angle rollers. the rev rollers seemed to work much better but we still had binding issues. Thoughts?
We typically climb using a winch system.
Pros - Easy to build, easy to program, easy to deliver whatever force you need via changing the gearing. Can use another existing mechanism (like your elevator) to deliver the attachment piece
Cons - Need a seperate delivery mechanism for the hook if you are climbing on a high attachment point, and can be slower
Mostly use a 1/2" box wrench ratchet to prevent backdriving. Pro - simple and robust. Con Makes your climber a one attempt system
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The chain was very heavy so yes probably #35, we used the REV 2 stage elevator ripped our all the confusing rigging and basically replaced it with a triangle of gear tight chain driven off the back with a standard tough box and two CIMS, The top gear replaces the original string roller the bottom gear was bolted to the frame ,that was the weakest part and sometimes looked iffy but it held through two events and a lot of climbed and scoring on the scale…we used a heavy strap for the other part to raise with the elevator the type they use for moving and securing furniture/refrigerators etc. It was simple and effective , hardest part was making sure the chain was tight. I would really bolster the bottom part on the frame as the was the only real potential fail part of this simple design. The hooks were very robust . The rollers were probably replaced from the original ones .
I’m not the builder, I’m the thinker so I don’t have the exact details. That chain drive system was not my idea, I just help with “what” not “how” , but I really liked that solution it as it gave the most reliable system on our robot 10/10 and that is always welcome.
So I hear you saying
But instead of looking at one mechanism you may be better off splitting up the different items that have to happen for a climb.
- Get a fastening mechanism at least 5’3" above the carpet
- Align the mechanism
- Lock the mechanism on the switch
- Lift the bot >0" off the carpet
- Lock the position of the robot
- Clear the carpet
Now instead of 1 complicated elevator to look at you have 6 simple tasks THAT DON’T HAVE TO BE TIED TOGETHER AS ONE DESIGN
EX:
1.1 elevator
1.2 extension rod
1.3 launcher
2.1 your drive train (hey this one could be done already)
2.2 swinging arm
3.1 hook
3.2 piston controlled claw
4.1 winch
4.2 legs that push you off the ground (notice that 4 is lift off not clear the carpet)
5.1 winch lock
5.2 rope with slack drawn in
6.1 if done don’t worry about it
6.2 raise legs
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how do you lock it so you dont fall down when the match ends? thats what really stumps me
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would i attach that to the motor itself?
It goes in a VersaPlanetary gearbox
thank you
You can also use a one way cleat.
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can you use it with a different gear box or does it only work with that one?
You would use that with a VersaPlanetary gearbox. The website has great descriptions on how to use them.
Only that type
In 2018 my team used a ratchet and pawl to prevent our elevator from back driving when climbing. We downloaded the CAD of both from McMaster Carr. The pawl was held up with a pnuematic cylinder until we needed it, in which case we retracted the cylinder and small spring caused the pawl to engage in the ratchet which was mounted to the end of our elevator drum.
It worked pretty well, although if you do something similar I’d recommend making them out of steel not aluminum.
Here’s a picture of the setup in CAD: https://drive.google.com/file/d/1tb515fL6Uz7Gocpo6zzF8pSB5HhZZj-h/view?usp=drivesdk
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