I built a concept string shooter design that fires two projectiles for each mechanism. It was meant to be as a compact as possible to allow more space for the robot, and the possibility of adding more of these types of mechanisms. Currently, the design is a c channel about 6” long
Current problem with the design is that the standoffs bend like crazy.
What’s the plastic bit on the catapult’s arm that connects it to the rubber bands?
If i had to guess its a modified bearing
This is also a problem we faced. It could be a combination of the hard stop and the rubber band pressure. I would try to make the standoff on the catapult run into something softer or more absorbant then another standoff
its a type of bearing that can be bought in the vex store, i think its to keep nuts in place
correction: standoff retainer
It looks like the new standoff retainer: Standoff Retainers - VEX Robotics
A clever idea for making linear sliders!
which standoff is bending
How far does it launch? Those rubber bands make it look like it would launch across the field in the air so a less powerful version would be just as effective but not as prone to bending its pieces.
oh dang, could you use a hs axle and drill into it?
I made a second arm design that doesnt bend (or as much)
This looks really cool! What is your method of deploying it?
Our area banned metal projectiles of any sort, so I had to use plastic, so it only travels like less that half the field length
I tested a metal nut and it worked good, but had to modify the double prong
What area is this? It should not be possible for a region to change the rules.
R4 gives the head referees quite a bit of leeway to interpret what might be considered dangerous. While not necessarily “changing the rules”, a group of head refs in a particular region (head ref’s tend to talk to each other…they don’t work in a vacuum), might all decide that shooting big metal nuts across the field might be a potential safety hazard, especially if a robot might accidently discharge a metal projectile by accident into someone’s face.
What is the standoff connected to so it doesn’t fly off?
Welcome to the forums!
What I did when I made it is I put a double ended screw (standoff connector) in the screw hole of a shaft collar (take out the baby screw) and then put the shaft collar on a screw joint. Hope this helps!