telescoping arm

[ahmed]

Originally Posted by KenWittlief

ahmed: Nice photo of your bot from last year. How did the arm extend?

did it use cables and pulleys? how many stages did it have?

Actually, quite sadly, it's my first year on the team. I *almost* certain though it used cables and pulleys

I'll try and check with my teacher

[KenWittlief]

that works pretty well as long as there is NO WAY for the cable to jump off the pulley - it has to be covered or the cable must have no where else to go.

this is how fork lifts raise way up BTW. same idea

[Mike Norton]

http://www.valleytech.k12.ma.us/robo...1Robot2001.jpg

this has five stages half of the 1/8" cable is inside of the machine. This was a push pull system. 2 different cables. one to pull out and one to pull in. This is not hard to do at all. the hardest thing was to make the squares out of thin alum. we went 14' with this machine. we went 9' the year before.


we were only 17"when the machine was completely closed. this kept our center of gravity pretty low.

[kevin.li.rit]

We had a non functioning telescoping arm for our 2002 robot. It would extend to almost half the field but it would always jam. We did it just by stringing it and then using the motor to wind up the wire.

[Yan Wang]

For the Canadian teams, see if you guys can get the engineers who worked on the arm for the Space Shuttles to help you guys.

I'm sure they'll provide the best input.

In fact, how can I get ahold of them?!

[KenWittlief]

That arm was designed over 25 years ago (Space Shuttle)

those guys are all walking around in florida now wearing white shoes and polyester sports jackets :c)

[Craig]

Hey Guys I'll shed a little light on our arm from 2003

It took 4 solid weeks to work out all the bugs in the telescoping mechanism. No pulleys or cables in that arm either. We used "fish tape" which is commonly used for running electrical wires thru conduit. it's like a 15' long piece of spring steel about 1/4" wide that we moved with two rollers. When retracted the tape was wound up inside the big brass ring that you see on the side of the mechanism. To tell the truth that thing was a pain in the $@#$@#$@#, it worked really well but only 60% of the time. That is until the bot fell on the mech in the first practice heat, from that point on it worked so well we could shoot the smallest extension like a spear, Almost lost my head the first time it happened!

[Jeremy_Mc]

My old team (442) built an arm that was 30' long in 2002. They used it to reach over all the other bots and goals and back to the home zone area. It used strings/pulleys/cables whatever. I'm not sure what kind of string material they used, but I know pulleys were involved.

Although I never really approved of building it, the few times it worked were kind of impressive. That is, until the top snapped off, swung by the string, and almost killed a referee. But, eh, it's all the same.

[Mr. Ivey]

In 99' Team 384, used an elevator to achieve the play. It was our first year, and I wasn't on the team because I was in 8th grade, but it used a pully system to achieve a 7 foot gain I believe. You could use the same system of pullies to get the height. But I would worry if you were to use the pullies to lift the bot as well, the cable could snap with that much weight on it... I'm not sure. I'm beginning to think that the bar is somewhat like stacking of last year, really great if you can do it, and it helps, but you can easily win with out it...
If you are using the device for grabbing the multiplier balls, don't go up and down, stay in a fixed location with an arm that moves from a stationary elevated point. It makes it so there is less to break.
Ivey