The motors are typically placed at the left (back) side of the double four bar as they would be in a typical four bar link. There are other ways of powering it, but they are less commonly used.
As to how many motors you use, it depends on how much torque you are going to need. Jordan used a 7:1 (driven to driving) gear ratio for torque powered by 4 motor 269s (2 per side) which seemed to work pretty well given the videos he posted of the competition. However, if you have a heavier manipulator or want to lift more game objects you may need more torque.
That will definitely work. Because you have the gear tower in the back, the double four bar in the middle and then a manipulator on the front, it’s a closed linkage. So when you rotate one of the back horizontal bars up and down the whole thing will move up and down.
If still have questions, try watching one of the videos of 24C competing.
Unfortunately this was the best picture I could get. Even though this basketball hoop does not lift, if it did, those 2 bars that created traingles would keep the hoop straight. This should work with vex also.
3-bar linkages create triangles, which wouldn’t work at all like you would want your 4-bar linkage to work. This is why triangles are very commonly used to stabilize structural pieces; because they don’t move.
It could be a 6 bar, but I think that the nature of the mechanism being derived from a “4 bar” The extended 4 bar would be a better name since it just sorta extends the reach.
But if we want to get technical a 4 bar isn’t really a 4 bar because there are only 2 bars needed to move, the reason its called a 4 bar is because you could the mounting points. If we want to name it based on the mounting points I think a 6 bar would work, but IMO the extended 4 bar is just a better name but again thats just me
