I have recently discovered an interesting type of four bar:
http://www.youtube.com/watch?v=jUxZb0fy31g
I do not believe that it would be very efficient this year, with the crazy 12" height restriction, but could be very useful in later competitions.
I like it!! Kinda like a reverse double 4 bar, in a few ways. The “back” of the lift (or what we would use as the back) does move up and down a bit with the other end of the 4 bar, so it could be useful this year.
Could you imagine the main 4 bar switched with a 6 bar? 
I am tempted to build that now and see how it works.
Great discovery! It would be interesting to see how practical this could be in VEX.
~George
One of my teams used reverse double 4 bar in gateway… it was technically challenging to build.
It worked pretty well during the Worlds (got knocked out at the Division SF by the then-World Champ)… and it even got a “Good robot” comment from Kartik… but that was it - it didnt win us the Design Award though.
Just a warning to those who are thinking of trying - reverse double 4 bar is really difficult to build. But it is definitely an achievement if you can pull it off effectively 
Hm, looks like it’s linear motion too, not just a parallel linkage. Definitely something worth playing around with.
There are some situations where linear motion like that will be useful, but this linkage takes up a lot of space and uses a lot more structural points to the frame than we are accustomed to doing on our robots. I feel like if you really want linear motion you should probably just go after some form of elevator lift, or learn to live with the rotational motion provided by a standard 4 bar.
I like it too for what it’s worth. It’s quite an interesting mechanical do-dad.
nice idea … could work
I see 7 bars in that linkage… I vote we name it a 7-bar.
:eek:
Well spotted sir.
Multi-bar linkages are not “4-bars”. “4-bars” are a type of multi-bar linkages.
GB