small scale winch

Is there such a thing as a small-scale winch with a quick release? My team is thinking of using a winch to pull back on a cable, which would put tension on surgical tubing up above. We plan on having some sort of quick release so it will snap and produce more force. Are there any other teams using this type of idea?

Thanks,

Mitch Guzman
Team Captain
#1566 The Ammoknights

We are thinking about using that idea. One problem we have already encountered (and are having extreme difficulty fixing) is the rule that you can only leave the robot for 2 seconds to hit the ball and back. That is the 3" outside the frame perimeter and before the end of the bumper.

The reason for this being, if it does not leave the frame perimeter, there is NO way to get enough force to lift the ball (which is one of the main advantages for kicking).

I was actually thinking about this a couple days ago, but I abandoned the idea because of complications. I’ll let you know what I came up with though.
I was thinking something akin to a cello tuning peg, where the cable would be fed through a little hole in the middle of a peg, and then the peg would be turned with a motor. When the peg is turned, the cable wraps around it and applies tension to whatever is attached to the other side.
And then I encountered the problem of the quick release. Depending on the amount of tension you will encounter, you’ll have to decide on what motor to use. You’ll probably need something that is geared for torque rather then speed, like a window motor. Unfortunately, window motors cannot unwind quickly enough to have a “quick” release. I started to think about using some sort of “cocking” mechanism to hold the peg in place until the actuation was needed, but I got lazy. Maybe you can figure something out? Just an idea :rolleyes:

StringsWound_on_Pegs.jpg


StringsWound_on_Pegs.jpg

Check out 1114’s 2008 puncher. I’m pretty sure they used a dog gear to winch it in and a pneumatic punch out for the quick release function.

Says the team that used a motor to winch in their shooter AND release it, that same year…

There are pictures of that one on CD-Media, too. It’s a really cool linkage.

shhhhh :stuck_out_tongue:

We must be thinking of a different idea. We are using tension on some surgical tubing to pull our kicking mechanism back. the winch cable will keep the tension and release it. In order to get lift without extending past the bumper, we are putting a “foot” on the end of our rod. we plan on having a worm gear that will lower and raise the kicking mechanism to get different heights. Then we will have a rubber stopper slightly past the contact point to absorb the force and keep the motor from being harmed. If you still can’t see what we’re talking about, I can upload a picture of our wooden prototype.
The prototype we build lobbed the ball (height of above 12") for about 12-15 feet. We only used about 80N of force to do this :slight_smile:

One idea (we intend to try, disclaimer, have not yet)

Pawl and Ratchet.

Searching the web, have found three sources.

Mc MasterCarr (Page 1053): http://www.mcmaster.com/#6283k24/=5fpwdn

http://www.qtcgears.com/KHK/newgears/KHK316.html

and

https://sdp-si.com/eStore/Direct.asp?GroupID=472

Hope that helps!

  • John

Consider using a dog clutch type of arrangement?

I’ve seen a few people bring up the ratchet and pawl system when someone is asking for a way to release a device. I don’t understand how a winch with this system will release without backdriving the motor unless another mechanism (dog gear, etc.) is also used.

Oooh, good call. I had forgotten. I apologize.

Use a “One-Way Locking Steel Needle-Roller Bearing” from Mc Master Carr on Page 1137 or similar.

Stick this between the ratchet and the motor shaft.

  • John

Maybe I’m a bit slow today, but I can’t picture how a one way bearing solves the problem of backdriving the motor. The bearing would allow the winch to spin faster than the motor in the same direction. Or did I completely misunderstand your suggested use of the bearing?