This is a claw prototype design for picking up and releasing rings. I got my inspiration from Dylon Tjanaka on youtube so thanks to him. It’s a fairly simple design using a piston and two prongs. If a team isn’t able to use pistons, then they can use a motor to pull the nylon string. Honestly, a motor would probably be better because it has higher torque. The claw can hold up to 6 rings from what’s been tested. I’m planning on flipping the piston around to where the tubing connects to the piston from the back instead of the front. That would help save space to allow more rings to fit in the mechanism because the connectors are out of the way. My goal was to be able to hold 8 rings at a time because that’s the amount that’ll fit on the alliance mobile goals based on cad. Something that I’ve learned and would be very helpful is that you can bend polycarbonate sheets without the use of a heat gun. If you give it enough force, the polycarbonate won’t return to its original shape. If you have any questions please ask, and I’ll respond as fast as I can. Also, please remember to credit our team in your engineering notebooks and anywhere else you need to. (Our team is 62449A)
Here’s a picture of the entire prototype claw. (NOTE : The finished claw wont include the reservoir; it’ll only go from the bottom of the prongs up to a few holes above the piston)
what these plunger-type intakes will excel at is quickly depositing a whole group of rings at once, which might be very powerful. However, they will also likely be slower at fielding than any sort of roller based intake, which might render them slower overall.
But this type of intake could definitely be the way to go if you don’t plan on fielding very often but still want to be competitive in the ring game.
As far as your specific design goes, I really like the polycarb prongs you use for intaking. Using a piston to release works well, but there’s probably a way to do it completely passively, or with power sharing from another mechanism (lift perhaps).
Seems like a nice combination would be to gather rings rapidly with a roller intake, then store them in stacks on one or more pneumatic actuated plungers. The stacks could be stored until just the right moment, then precisely and quickly placed on available branches.
I do have a question about going for fielding. Since the neutral goals have elevated branches, especially the center neutral one, couldn’t you go over and easily knock the rings off of the branches? You could play very aggressively by stacking as many rings as possible on the alliance goals and descoring after you’re done. The opposing team can’t even descore the rings on your alliance goal.
I like your design a lot. It’s simple, yet highly effective. It looks as if ring are released when the cylinder is in the non actuated position. You might consider finding a way to reverse that, so that the default action of the plunger is to hold rings. It would then release rings only when the cylinder was actuated.
The piston I used in this prototype is a two way cylinder, so it shouldn’t be an issue. I could, however, flip it around to where the piston is pushing up when actuated. Thanks for the advice though! I’ll keep in in mind for the future.
there’s no piston limit so is there any point to making it completely passive? their pneumatic release seems faster and more consistent than an passive release I can think of.
you are correct to say that alliance goals are going to be the safest and most reliable place to score rings on. however, the points from the high branches on the tall neutral goal simply cannot be ignored in my opinion. The best way to stack on that goal is going to be to do so while firmly grasping the goal inside your robot, so it can’t be tipped over. if you hold it steady enough, even opponents ramming you should in theory not be able to do much damage to your rings.
there is no piston limit, but there is an air limit. if you end up actuating this plunger many times during a match, you’re probably going to use a large portion of your air doing so. Which leaves less air for other pistons to use elsewhere on your bot.
It might depend on the team and the robot If they can’t afford pneumatics, they won’t be able to build it. Pneumatics also add to the weight and take up space which might not be available.
Good point on the air limit. I’ve tested the claw and it was able to consistently release rings about 15ish times with one reservoir. It got down to about 30psi before it stopped releasing correctly. Honestly with two reservoirs and nothing else really to use the air on, it might be a good option.
Technically, there is a “piston limit” which is one piston per pneumatic cylinder, since you are not allowed to modify pneumatic cylinders
I work in automation, and I would lose my job if I ever called pneumatic cylinders (or air cylinders) “pistons.” I would encourage the VEX community to use proper industry-standard terminology, it sets you up better for a technical career.
This looks like a very promising idea. As Xenon27 said: [
“but there’s probably a way to do it completely passively”
My team did investigate doing this passively in both directions. It is defiantly doable, especially if your team does not have pneumatics (like ours). We made a prototype out of LEGO (we do not have access to the VEX parts yet), and here are some pictures. The pieces covered in blue tape (for visibility) can pivot into the mechanism to allow rings to slide past them and rings are released by the tan gear getting pushed up (to the left in the pictures), causing the sides to angle out.
Use a one way position and you will consume half as much air pressure. There is a spring that keeps it “contracted” so pressure is only used when it’s extended.
That’s a good design! I’ve also considered doing one of those designs before. The only issue I ran into with my design is that the rod that pushes out the prongs tend to twist. The standoff in the image was supposed to be attached to a pneumatic cylinder.
Actually, the prongs pull themselves back into position. Because of that, you don’t need to use some air to extend the rod out. There’s a link in my video that shows the claw releasing the rings and the polycarbonate pieces going back into position without the use of any air.
It makes a lot of sense to actuate the air cylinder only when you want to release the rings. In actual game-play, it might take several attempts to spear a ring (and you might want to pick up several rings) so you won’t be wasting your air until the single actuation to release the rings. You’ll need to review how many actuations you can get from your air cylinder, and if you can regulate your pressure down, you’ll get more actuation on an air tank (but they will be a bit slower).
This is called a “single acting” air cylinder. Although they do use less air because the are retracted by an internal spring, you consume air “fighting the spring”. A double-acting cylinder can be used in the same way be leaving one port of the cylinder open to the air (plugging the extra port of the solenoid), and using your own spring (rubber band) of just the amount of tension needed to retract the cylinder.
I feel like the real question here is is a claw or a plunger the meta for rings? It is a nice claw/plunger, but it might not be able to keep up with rollers.
