Hi
My team is using a 2 bar with high strength chain linkage this year. I have had some previous experience with this and I know how it works, but I was wondering if anyone had some helpful suggestions.
Thanks
2009-2010: Energy Award- Mt. Michael
Energy Award- U.S. National Tournament
2010-2011- Tournament Champion- Waverly
School Champion- Omaha Mid-Continent League Play
Design Award- St. Cecelia
Tournament Champion- U.S. National Tournament
Don’t know if you’ve seen this yet, or if it’s just stuff that you already know, but it might be worth having a quick skim read to see if there might be anything helpful : http://www.aura.org.nz/archives/991
Whoops, sorry! We get quite a lot of e-mails from teams, so it’s hard to keep track! Perhaps if you have a specific issue with your lift that you can describe, or something specific that you want to improve, or if you have some photos, we might be able to help you out some more?
One thing we did wrong when we first made one is put the tower at the back of the robot and made a super long arm. This meant that when it was all the way up, the front of the intake was at the back of the robot… so what we did is put the tower in the center of the robot and made the arm shorter so that when the arm is all the way up it is in basically the same position as at the bottom, as you can see in the attached photos (B lived on after world cup) -
as you can see, the intake is almost in the same position (forward and back) in both down and up positions making it less likely to fall over
another thing we found with this is that the bigger the sprocket you use the better (cant remember why now) - just when you use a bigger sprocket, the arm becomes longerishkinda and the pivot on the tower becomes lower, so we used 24T sprockets.
Redundancies with this type of lift is important as the chain often breaks, the smartest way to do this is to tie string so that if the chain breaks the string comes into play. My world cup robot (A) had all the links cable tied together, but i think justin (B) did it alot smarter with chain - shown below
when doing this you have to make sure that the string wont go onto the sprocket though
Another thing we thought about doing but didnt in the end is to make the sprocket on the intake end smaller, meaning it will rotate more and not stay parallel. This may sound silly, but if you adjusted it right it would make you intake change angle as it went up so it is basically flat at the bottom so it is easy to pick objects up - and then almost vertical at the top so the objects fall out easily.
as you can see, the intake is almost in the same position (forward and back) in both down and up positions making it less likely to fall over
another thing we found with this is that the bigger the sprocket you use the better (cant remember why now) - just when you use a bigger sprocket, the arm becomes longerishkinda and the pivot on the tower becomes lower, so we used 24T sprockets.
Redundancies with this type of lift is important as the chain often breaks, the smartest way to do this is to tie string so that if the chain breaks the string comes into play. My world cup robot (A) had all the links cable tied together, but i think justin (B) did it alot smarter with chain - shown below
when doing this you have to make sure that the string wont go onto the sprocket though
Another thing we thought about doing but didnt in the end is to make the sprocket on the intake end smaller, meaning it will rotate more and not stay parallel. This may sound silly, but if you adjusted it right it would make you intake change angle as it went up so it is basically flat at the bottom so it is easy to pick objects up - and then almost vertical at the top so the objects fall out easily.
of course it could! what use is a robot that cant score 30"? ok, i lied, it reached 29" but the intake bumped it over the last bit, the further forward the tower = the shorter the arm, so if you want it longer just move it an inch or so and make the arm longer
Personally I disagree. I could never consider a robot that doesn’t score in the 30 inch goals “good”. Scoring in 30inch goals isn’t like ladder climbing, which was optional and could be made up for. I think it is a complete necessity, and it is almost impossible to have a competitive robot if it can’t score 30 inches. More, it separates the competitive from the newbies? I dunno :p.
I would actually have to agree on that one. Although in addition there also the teams who aren’t knew but won’t put the effort or skill into making 30 inches.
I think I would like taller scoring elements We have that part figured out pretty good here.
But in all seriousness I have always loved these kinds of arms, and have wanted to build one, but due to budget purposes we will not be building one, this year at least.
ok, i lied, it reached 29" but the intake bumped it over the last bit, the further forward the tower = the shorter the arm, so if you want it longer just move it an inch or so and make the arm longer 
We have that part figured out pretty good here.
