The current competition is the Starstruck one. People have approched the problem of lifting stars and cubes over a fence in many ways. Most popular so far have been the claw-bots. These robots have giant claws to grip the objects. The claw is attached to some arm or structual pieces. These pieces are attached to a gear mechanism.
But has anyone attemped to instead of a gear mechanism use a pulley system? I’m not good with vex pulley system stuff, so can some one explain to me how pulleys work and why they are useful. Also I would like to know how to build one using vex pieces. Can pulley systems be various, like gear ratios? Is there such thing as a 3:1 pulley system ratio?
And finally, I would love to know if any team out there has attemped to build a robot using these concepts. Thank you in advanced!
My team had personally never built a pulley system in VEX before, but there are many tutorials explaining how to make one on the internet, in VEX they are usually called “elevator lifts” so if you type that into youtube or google images with VEX following it, I’m sure that a tutorial will pop up. If you plan to use one yourself, just know that they usually have been less superior to the regular lifts you’ve seen due to the difficulty in making one. But don’t let me discourage you, if you can figure out a better way to build the system, then good job! But good luck either way!
I know of a team that used a pulley system to pull their robot up for a high hang. the only problem with a pulley system is you need tension so that it will raise by itself and you’ll need a lot more torque to lower it. so it just seems too slow to me, but using it for a hang wasn’t a bad idea
That’s one of the main weaknesses of the pulley system, they are extremely slow, but for hang its not that bad of an idea
But why are they slow? Is it like a torque gear ratio? It only adds strength? Is there a way to make them quicker? I know I’m asking a lot of questions, but I’m very intruiged.
with a pulley you need to have a way for it to rise up and if you are using that as a manipulator you’ll need a lot of tension, meaning you’ll need a lot of torque to go against that tension and it’ll be too slow
OP, are you referring to a block and tackle pulley system or the “elevator lift” in a previous post? Block and tacle would use string, elevator lift would use chain.
Well, is it considered a pulley if you use chain instead of string?
Good question. I’m not sure. That’s why I asked. The picture that is linked shows a chain system (at least I think…). It looks like sprockets and chain.