Hanging Mechanism

Technical Technical Discussion
1

Hi!
Geeetings from the green rockets 7554, our design team was thinking about hanging mechanisms the other day and decided on using a rope to pull the robot up. After alot of thinking we couldn’t come up with mechanisms that would keep the robot hanging after it gets disabled. Based on your past experience how would one make such a mechanism?

We’d love to hear from you soon!
Thank you in advance.

2

2656 bolted a ratcheting hex wrench onto our frame which forced our climbing winch drum to only spin in one direction. That, coupled with our 50:1 gearbox, kept the robot hanging as long as need be in 2017.

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If you use a ratchet to pull up on a rope, a ratchet of some sort is a very good option. Except when you use one that doesn’t auto-return to the direction you want it in. We got stuck in 2018 being unable to climb many times because we forgot to flip the direction of our ratchet wrench.

4

Yes, simply, a ratchet around the hex bore of the axle on the other side will hold it in place.

Have to be conscious of that though, since climbing is a one-shot ordeal at that point.

6

Another option that teams have used for hanging or just elevators in general is a disk brake, similar to the kind used on a bicycle. Actuate the brake with a pneumatic and that will hold, while allowing reversibility.

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I would choose on of these options:

  • Ratchet on a winch. A ratchet mechanism will allow the motor to spin the winch to lift the robot but gravity woulnt be able to lower the robot. An easy to use and implement ratchet can be on vex site https://www.vexrobotics.com/217-6048.html and it can be installed easliy on a vex planetary gear
  • A brake system can be used to make sure the elevator doesnt fall when power is disconnected to the robot. A small pneumatic piston can press on a bicycle brakes to stop the elevator from falling
  • Worm gear connected to the motor and to a winch can both reduce your speed and give you torque and it also cant spin backwards as a worm gear can only be driven from one side.
8

You could buy (or build your own) cam cleat as well.

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