Hi FIRST Participants!
Just wondering what ideas some other teams had for hooking on to the tower pull up bar. Our team has looked into carabiners, but we havent found one large enough or that is weighted. As of now, we are looking at using a steel hook or making ine from fiberglass. We would really appreciate any ideas or suggestions!
Check boat and dive shops. Mariners have invented all sorts of neat ways to put a line on a rung. There’s even one called the “happy hooker” that basically threads the needle for you. It has a piece that toggles back and forth between two pivots, and the bottom line is that you just have to push the hooker across the rung and pull it back, and you’ve threaded the rung and are pulling back the bitter end. A bit pricey, but very cool, and reliable as well.
If you have a CNC or basic mill this kind of clip is a good option. We plan on doing something similar, but somewhat different. It’s basically an oversized gate latch.
Carabiners can work, but you need a person to reach the clip to unhook it at the end of the match. The gate latch or other hook that can be released from a line or stick is best bet.
I don’t think they generally make climbing carabiners that size, but even if you could find one you would have a problem, carabiners that size would be for some heavy duty mountaineering, as such the have a latch on the opening portion, so that it cannot be pushed open, but rather you have to rotate a screw to unlatch it. Also those types of carabiners are built to withstand the force of a person falling at several meters per second stopping suddenly, so they are large and made of very heavy duty (and heavy weight) material, which could cause a problem for a robot with a strict weight limit
Used to hook on ladder rungs. 
Back in 2010 to climb we placed a custom aluminum hook above the bar using a telescoping PVC arm. We then retracted the arm, leaving the hook on the bar, and then winching ourselves up with a cable.
In 2013 we made two custom spring loaded latch mechanisms to grip on to the 10-point bar of the pyramid from below. The latches were extended and retraced with 2 pneumatic cylinders.
see, its got a block / stopper that you have to unscrew or twist to open the gate, making it hard for a robot to use
I think I can bypass that. It’s actually not all that hard. All you have to do is stop the lock from engaging, and that could be done with anything from taping it back to putting a pin or setscrew through the lock to completely removing it.
That being said, if you do do something stronger than tape, I would also suggest that after the robot is totally scrapped the carabiner should probably be pretty thoroughly labeled/physically damaged so it won’t be used for climbing.
Thank you mentors and fellow students for all your help and ideas! We really appreciate it.
We have used Harbor Freight carabiners in 2013 to hang from a similar sized bar, we just cut them to size to make them work.
http://www.citruscircuits.org/uploads/6/9/3/4/6934550/708317_orig.jpg
You could make that easily with a drill, some quality time with a hacksaw, and a little love with a file.
Something like this? From rock climbing; the stick clip