Speaking of the catapult, has anyone built a trebuchet? Trebuchets are pretty good for lift-and-throw. While it would seem to be quite difficult to set up a good counter-weight for a gravity-driven trebuchet, I suspect you could use motors to set up a good pull trebuchet.
I think people are overlooking something. Double four bars and scissor lifts are huge space takers. Linear lifts and cascade can take up only a relatively small portion of the bot and get good height. Its a tradeoff of speed or size. And being logical here, more size is more weight, which means less efficiency.
Thats not true, (like a kg of feathers vs bricks) and linear slides are only made of steel, and linear slides are heavy af. Plus linear slides are not very efficient due to friction, while rotational shafts are very effecient in vex
I don’t know why there’s any debate over this at all. Skyrise demonstrated that the double reverse 4-bar (or double reverse 6-bar) are the best lifts for this kind of height. It seems pretty cut and dry to me.
I would agree that they are probably the best this year for the lift. Mostly because they are much easier to build than scissor or elevator lifts. But I do also think, if built well, that a scissor lift can be on par with it.
People need to stop thinking the tradeoff with linear elevators is speed. That’s just flat out wrong and not based on any solid evidence other then anecdotal poor evidence.
The tradeoff you have to fight more with linear elevators is friction and often times depending on how the lift is constructed offset loads. Find a way to solve these issues and a linear elevator can keep up or beat any other lift all day long.
My original plan was to build a reverse double 4 bar with a 62 flipper on it, but after building a prototype and seeing other videos of the same design, I concluded that this design would be much more difficult than I imagined, all because of the lack of space. instead, my plan now is to build a scissor lift and a 62 flipper, its just a matter of “perfecting” the scissor lift and getting to work as fast and efficiently as possible. While the dr4b is probably the quickest, they are very inefficient in terms of space they take up.
Sorry to dig such an old post, but I just stumbled across a really interesting lift concept that I thought I’d share here.
As you can see, this mechanism is very unique. Although I do think it’s possible to build out of vex parts, there are a few limitations of the lift. Here are my initial thoughts.
-More space efficient than a DR4B
-No linear slides
-Doesn’t require lift towers: the bottom parts of the “A” could be mounted to the chassis.
-Unexplored: making it viable would require some serious innovation
-Top is an axis, not a bar, so it’s difficult to mount mechanisms on. Getting a bar attached and making it stay linear would require some experimentation.
For anyone who tries to make this lift viable, good luck! (You’ll need it )
I think this is a semi-pro, semi-con as it’s only partly true. This is more space efficient in some ways and less so in other ways. It’s more efficient in terms of volume and some dimensions, but not all dimensions. The problem is the height limit. If you make it as compact as possible vertically (collapsed downward), it has to be about 3/5 (quick estimate) of its maximum height. That means it cannot reach nearly as high as a DR4B within the VRC constraints. That’s why I’m saying it’s not as space-efficient in every way.