Crossbow like ball launcher

[krazypandah]

So our team has an idea of making a crossbow luancher to launch the balls. We're thinking of using metal springs to luanch the ball and to pull the strings back we are using a motor that will pull the ball back then will attach to a hook that we can then release for luanching. Will this even give us a good distance and has anyone else tried this.

it wont neccesarily have limbs, we're looking at attaching the springs to a frame that will be connected to the ramp the ball goes down something with a board underneath that will connect the ramp and the frame and we will load the balls through the front with a conveyor belt that loads to the ramp and then a motor will pull back the springs and then WHHOOOOOOOSH.

[krazyman1013]

How are you planing to load the balls? If you don't have a loading mechanism I suggest that you figure that out first.

[tetravaal]

Just my 2c here.

Be careful about complexity. My team still runs into things where we take real life scenarios (Crossbows), and then try to translate them into robots. I think your difficulty will come with a latching mechanism because they are inherently harder to get working (Holding 100lbs force but using 2lbs to release).

I don't know how advanced your team is, but a "Ball pitcher" will be a lot simpler mechanically because you just feed the ball in and boom its away.

:-)

Joe

[sjspry]

My team's two options right now were a pneumatic catapult, and something similar using springs (dep. on if using pneumatics will end up saving weight). Instead of a crossbow with limbs, maybe just a spring being ratcheted back?

[karomata]

If this idea works, I love it. I'm trying to push my team to build a catapult this year because of the better chances of scoring, but the main concern is that a catapult isn't accurate enough. A crossbow would solve this problem.

[Gary Dillard]

Check out team 1523 (MARS) at the Florida Regional in 2006; they used something similar that was very effective. Videos available on thebluealliance.net.