Hey guys my team was interested in using a double 4-bar and I remember that there was a chinese team which posted a thread reavealing their robot which used one.
Could someone please post the link to the thead?
I might post a teaser down the road. We have huge plans for this. I know you guys will want to see the second you hear about it.
Thanks.
Yes. Thank you very much!
No problem 
It is not a chinese team… we are from Singapore.
Anyway, disciple855 has posted the thread… hope you will find it useful.
For info, the double 4-bar worked well through the Worlds… you might even want to take a look at some of the matches played during Worlds involving the team… 8059C (in Tech Div).
Have fun building
I really liked your lift design. it is very innovative and looked like it worked well.
It did worked really well… until we met 2W!!
I can never think of such a robot like 2W… when i first saw it, my reaction was…“It’s a freak (as in… unique and out of the box)!!” :eek:
I’m sorry about the region mix up.
And I will definitely look at some of the matches.
I would expect to see a reverse double four bar on our robot because as of right now everyone on my team is on board with the idea.
No problem at all.
Just glad that there are people who still remember and appreciate the double 4-bar.
Well… for all that you know, maybe the double 4-bar might end up as popular as the 6-bar for the new game
The reason we want to use it is because of the linear path of motion rather then an arc. (I understand that both 4-Bars have to be the same length to be completely linear for the path of motion to be completely linear.)
We also have a special plan for it. 
The double 4 bar reverse thingy looked awesome!!! i wish i could have seen it at worlds.
There are many other advantages for a double 4-bar… we like it because of the small angle of rotation and it is efficient.
Our double 4-bar are not the same length.
Special plan = descorer?
The problem I see with the double 4-bar in Gateway is that it is a linear-ish path, which means you can’t get much reach forward with it, making it harder to reach goals.
But in Sack Attack it might be very useful, as it keeps the (heavy) objects closer to the center of the drive base for more stability, not to mention having more vertical lift ability given the problem with driving under the 15" troughs while having a 17" tall arm.
Hmm… we didn’t have any problem in reaching the goals… except for scoring the 30" from iso… which we tried to overcome by having a smaller base.
I guess the linear-ish is a double-edged sword… on one hand it does limit its reach, on the other hand, it does allow easier aiming as well.
But I agree… it might be handy for the new game… in fact, most likely we will be keeping our double 4-bar (with modifications of course) 
Does the double 4-bar raise faster than other arms?
We didn’t really timed our double 4-bar with our normal 6-bar.
But my guess is that it seems to be faster simply because you don’t need to rotate as much as the 6-bar in order to reach the same height.
A double reverse 4 bar would probably be faster in a competition setting and it is much easier to drive. My team ofound that they’re very inefficient.
So you’re saying that it is easy to drive and fast in competition setting, but it is not very effective?
Tony, that’s team 8059… you could have seen their thread before worlds… Or just go to the ustream page and go to Engineering QF 1-1.
i said “inefficient” not in-effective. It does not use the power the motors supply efficiently.