Team 357 Winch Test

The first test of 357’s winch mechanism. It’s far from finished, but I hope this inspires some more hanging mechanism posts.

nice prototype you got there
can i ask a few questions?

  1. how heavy is the robot?
  2. what did you use for the “rope” (i think i saw zipties and elastics?)
  3. what was the winch ratio?
    and keep building! :slight_smile:
  1. I don’t know the exact weight of the robot off hand, I’ll give that a check at our Thursday meeting.
  2. Three PWM cables, braided together.
  3. A 36 tooth gear was coming off of the (single) motor, onto the 84’s on the spool. We were all surprised at how little it took to lift the robot.

These things are all going to be played with this week into this weekend, We’ll keep updating to a certain extent, but I don’t think we’ll make final specs available until shortly before our next event. Come on out to the DC Knights Qualifier if you want to see it in person!(No promises on that, but I always like to give our events a plug)

How did it hold after you weren’t pushing it up anymore?

Not long at all, but that should all be worked out within a week.

How does the hook of the winch get on top of the ladder?

That’s legal ?

We didn’t see anything in the rules that prohibited it… and it’s a VEX part you can buy from the store (36" PWM cable) -

With the right delivery mechanism, this shouldn’t pose a risk for entanglement.

One could question it with R15 -

<R15> Parts may NOT be modified as follows:
a. Motors, extension cords, sensors, controllers, battery packs, and any other electrical
component of the VEX Robotics Design System may NOT be altered from their original state in
ANY way.

The cables themselves are still in their original state and have not been physically changed.

Perhaps a ruling from VEX would be in order.

The question of using electrical cables as “ropes” has been asked and answered in past seasons (legal).

If this season’s rules haven’t changed to forbid it; then the previous answer is still good (according to me).

Just post a Q&A, it’s really up to the Vex people and the judges at the event. If the Vex guys OK it then you can print out the Q&A and show it to the inspection judge at your event. The determination is still up to the judge but having the Q&A post helps.

Cool lift Andrew, I might add a little bit more gearing to make sure the lift can take the load, thats all.

How are you intending on hooking to the ladder? I hope it involves a grapple like device!


I like the winch. I think you need a bit more of a reduction than you had there, though. It just looked a little unstable and after a match of heavy battery usage I’d personally rather be safe than sorry. 1:5 should be fine, I bet.

I like the progress your team is making on the arm. I’m starting to buy into the idea that a single tube grabber that’s agile enough to reach over and around things like robots and towers will be successful this year, and it looks like you guys are subscribing to that philosophy as well?

Agreed that additional reduction may be necessary.

Ideally we would like to integrate the hook delivery with our tube scoring device for simplicity.

The one tube at a time has worked for us at earlier events due to other teams having a lot of trouble scoring with their multi-tube mechanisms. I think as this year progresses, the multi-tube bots are going to have a big advantage and we will be trying a new mechanism at our next event this weekend. Hopefully we’ll try out the hanging device as well.

Also, I think this was when it was using one vex motor to lift the robot. When we added another it didn’t have as much trouble (going to try it with a high strength motor next) -

didnt want to start another thread for something similar
but here is a video of our prototype winch

  • excerpt from the video description*
    ONE vex motor can provide more power than you think…
    we did not weigh the chair yet, but we’ll do that soon
    that was a prototype video, and now our robot can hang :slight_smile:
    I will post another video using braided anti-slip mat

if you turn the power off it WILL back-drive
but with little creative thinking you can solve that problem EASILY :wink:
not going to give you ALL the answers :stuck_out_tongue:

feel free to ask any questions :slight_smile:

here is our other vid
my friend combined the vid posted above with the “braided anti slip mats” vid
you can skip to 0:28 for the new video