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Originally Posted by Drew Hopman
While we are on the topic of how things work… Does anyone know how telescoping arms work? I had seen last year team 890 had a telescoping arm but I can’t figure out how to get it to work. Please help me.
Drew Hopman
Team 801
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heh, you must have the same idea we do.
Ok, telescoping arms.
They are relatively simple, and this idea on making one is just something that hit me in the face while I was thinking about it. Call it intuition, or whatever. There are probably better methodes, but here goes:
You have the man (non moving) stage of you arm, right? you make the secondary (moving) stage of your arm capable of sliding up and down the main stage. Now, at the TOP of the main stage, attach a roller chain sprocket, a small nylon one with a built in bearing would probably be best on weight considerations. Now, run a chain (you can use really small chain for this) over the sprocket and anchor it at the BOTTOM of the secondary stage. Now, with the other end of the chain you can attach a motor, so the motor can real in the chain. As it does this, the secondary shaft is forced to slide up the main shaft, and you have a powered, telescoping arm. You can make the chain complete the loop if you want more control (I.E. you attach the secondary stage to one link in a continuos loop of chain . . that loop is your main stage.
You can expand this into a three stage arm if you add a sprocket at the top and bottom of the secondary shaft . . so the chain goes over the main shaft's top sprocket, under the secondary's bottom sprocket, over the secondary's top sprocket, and is anchored to the bottom of the third stage.
Another simple design I saw last year is using your elastic tubing to load your telescoping arm, and you could pull a locking pin out allowing the elastic tubing to extend the arm. You can't retract it, though.
Pneumatics could work for a short one, but I'm currently working on an inventor design of my chain one.