New Zealand team suckers

My team was inspired by the sucker of 2921, 2915, and 720. We have our sucker built but we are not sure about one part. We have figured out how to keep our sucker up at the beginning of the match, but we are confused after that.

Once the sucker falls down, how does it stay down? (What prevents it from going back up or bouncing up and down?)

Lastly how did u guys allow your sucker to contract and expand for game objects? Currently our sucker can pick up most of the objects (Not at the curve sides) But if we make the space between it to big the sucker can’t pick up barrels on the curved sides, while if we have the space between the sucker to small the objects would get stuck. (Conveyor would stop moving)

We are stumped with these problems. Thank you for all the help! It is greatly appreciated.

Short Answer: rubber bands

Speaking from my personal experiences in building one with help from 2915 (I’m not sure exactly how the other teams did it, but i assume similar), my intakes are on 1x2x1 c channels 10 holes long, attached by a single long screw (with a nylock on the end). They have enough sideways flexibility to bend outward a little for the larger orientations of objects (they are originally sized to the sideways barrels).

Hope this made sense and helped you out

Could I get a better explanation for the rubber bands part? Like a long answer?

I’ve attached a sketch (MS paint-you might have guessed) illustrating how rubber bands could be used to hold the sucker down, against the objects, while not pulling the sucker down prematurely. The rubber bands would go on the sides of the intake, and would probably start stretched over the axle that the sucker pivots on.
The rubber bands provide both more friction and more control to the intake, but it also makes the sucker wheels harder to turn (more compression/friction).
sucker.JPG

If you attach one end of the rubber bands to the intake mount, and the other to part of the chute directly beneath it (mine is the metal which bolts to the sprocket on my chain arm) it will put a lot of tension pulling them downward. Most of us NZ teams have issues putting the intake up because there is enough tension that if the robot moves too quickly or too suddenly, they fall down. This is basically to ensure that they’ll come down when the intake turns.
This is a photo of my intake, sorry for the poor quality, but you should be able to see the rubber bands under the motor.
If you attach the bands on a slight angle, it should also help pull your intakes together a little for the sideways barrels, although it can cause some twisting depending on your intake mount and where you attach the bands.

You said you’ve already worked out how to keep it up, but just in case, most of us have a screw sticking out from the arm which we drive one of our intake paddles into to hold it up, so when the intake turns, the paddle moves away and the whole thing flips down.

Our collector is actually still in tension while in the folded position. However, we use vex standoffs as hooks to keep it there until it moves, at which point it flips into sucking position.

Sorry forgot to add that we use rubber bands to bring it down. Our advisor keeps complaining that the sucker wont stay down to suck game objects in? Is this true?

As long as you have enough of them it will stay down. If you only have, say, one rubber band; they may bounce a lot. But if you have three or more it should be alright. Experiment with yours and see what works