4Bar vs 6bar

Dear forum, i have seen extremly succesful 4 bars and 6 bars, what makes one better over the other, discuss

We had a four bar, but we found it would do better if we had a little more height, so we upgraded to a six bar, and it has worked quite well for us.

We had a 4 bar but the towers started to bend due to weight from the load we held in our claw, we moved to a 2 bar because it seemed better to make it high hang and easier to throw objects. I do not have any experience with a 6 bar but from observations its is pretty good

Usually, the only benefit from more bars is the height.
However, the more bars you add, the more you can mess with the geometry of the lift. Doing so can lead to the following:

  1. Slow lift at the start, fast lift at the end
  2. Gear ratio manipulation
  3. Making a tilt or reverse-tilt bar
  4. Making a locking lift, in that when the lift is all the way up, the motors cannot be backdriven
  5. Allowing for perfectly perpendicular lifting of a claw or something while having the lift towers themselves slanted (our setup)
    However, 1, 4, and 5 are only possible with 6+ bars.
    With MANY (nonstandard) bars, you could even force the end of the lift to move in the shape of ANY polynomial-graph. There’s a mathematical proof out there somewhere. Additionally, IIRC, you can do this and force the end bar to tilt in any way (within a certain range) throughout the lifting cycle. But these motions require complicated setups that have 16+ bars. (estimate)