I have been looking at past robots for fun recently and I came across this robot, The one thing that intrigued me was the linear punch and how it was actually actuated. It looks like it might be a ball screw or something along that line but how would that be able to release in such a quick amount of time. If anyone had pictures or explanitions that would be awesome. Thanks!! - Justin
You can download their CAD from here. It’s personally one of my favorite robots. Them, 67, and 548 in 2014 all had really cool robots that had linear punches
Ive looked at the cad but when downloaded into onshape It is confusing to look at. Ive just downloaded to Onshape so that it doesn’t take up space on my computer and maybe not everything imported properly. But there’s also a lot of mechanisms in that area so an explanation would help more.
67 has CAD on their TBA page from 2014.
We use Constant force springs for the motion, Chain drive for the retraction and a car door latch for the release. Very similar to a locking elevator from the 2018-2019 games.
It worked very well for handling a large game piece.
How did you relatch the springs so you could pull them back again, was it on a pneumatic and the latch just grabbed a bar or something?
It was a servo powering a latch, we had a 3d printed trigger for the car door latch.
Ill have to download the cad sometime, im currently on a chrome book and Ill probably kill the computer trying to upload it. (ive tried the fans start whining)
It was my freshman year, so I dont remember all the details specifically. The CAD should help you get an understanding or if you have some specific questions I can ask our lead engineer.
Thank you ill look at it when I can. I understand how the punch part works im just confused about the pull back and release on 118 and I cant tell from their video
I don’t know specifically how 118 did it, but a lot of teams would build shifters into the winch or screw that pulled back their punch, firing by shifting into neutral. This is easier with a ball shifter than a dog shifter, though there are durability and shifting force concerns.
But how would this work if you were to bring it back with a lead screw.
Weren’t they talking about one of these at one point?
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There are some better details available on their 2014 build blog, but I honestly wouldn’t use 118 as a design reference. 118’s robots are fiendishly complex, and they take full advantage of their very substantial design and manufacturing resources.
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Im just looking at the mechanical side of it for fun. I like looking into different ways people have accomplished the tasks for shooting single objects, similarly I love 148 2016 catapult just cause its awesome and mechanically cool.
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So I figured out I think, they have this locking linkage that is used. I dont fully know what type of linkage this is but its cool. I wonder how strong their spring was.
A Sea Catch over center linkage is used to grab the spring and pull it back, compressing it. The Sea Catch is attached to a carriage driven by a ball screw. A string pot measures the carriage position and allows for varying the shot power. There is a pneumatic cylinder that can be seen in @NustinJewton’s post that releases the Sea Catch. The whole shooter head is mounted on an arm that has a few preset positions that a pneumatic cylinder locks into to control the shot angle. I’m not sure specifically what spring was used but it was several hundred lbs/in.
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Thank you that is an awesome answer, Im guessing the over center linkage keeps it from overpowering the lock and coming undone early. It was an awesome bot and I loved the use of the linear punch I got the inspiration to look into it after the last cadathon when someone had a similar design on there robot.
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