We have a competition in about five days, but we’re stuck trying to figure out a way to keep our roller intake system (which flips out at the beginning of the match) from staying rigid and exerting enough downward force on the sacks to intake them efficiently. We’re also looking for ways to improve our intake roller… we’re trying to come up with ways to intake sacks more efficiently than our current tread-paddle-stand off system (see picture below)
Although we can’t make any major changes with a competition so close, any suggestions would be much appreciated.
We were thinking of using rubber bands, but if they somehow broke, we’d be pretty much out for the rest of the match because our intake may dig into the field. We were thinking of putting stand-offs somewhere to stop the intake when it falls, but so far we haven’t found a good spot.
We’ll definitely try replacing the stand-offs with screws and lock-nuts though
What you can do is use the black surgical tubing that VEX sells. It is VERY hard to break unless you have it stretched 100 times past its limit or rubbing on jagged edges. It also doesn’t wear out like rubber bands do.
You have the vertical c-channels (on the front of the arms) mounted on the outside of the arms. This necessitates the need to use stand-offs to reach back in to join to the intake ramp. Move the vertical c-channels to the inside of the arms so they can be bolted directly on to the side of the intake ramp. Move the 2 towers further apart to get the arms at the correct width for this. This will make everything less flexible, you will require a much shorter (thus stronger) pivot bolt for the intake roller arms (Jacko’s suggestion previously). Also, this will move the vertical c-channels away from the chassis (as they look in danger of hitting the chassis at the moment) and will make it easier to mount a lower stop for your intake roller arms to fall on to.
A c-channel cross brace, joining the 2 intake roller arms, would help make this structure a lot more rigid.
Your intake ramp looks optimistically long. I would guess that sacks would only ever occupy the bottom half of it? Remove the back half, if you can, to save some weight.
We have a very similar design; it’s a 6-bar, but we have a top falling intake mechanism using sprockets and tank tread flaps. The two sides are joined by a chassis rail with standoffs, and gravity just keeps it down. We take advantage of the semi-rigidity of using double tall conveyer belt flaps by allowing the intake to sit a little lower than using standoffs on the conveyer belt.
To keep sacks from piling up and flipping back over, we used the pivot of the intake to attach a couple of sprockets chained to another between the large intake sprockets. It makes sure the sacks don’t pile up right at the intake, increasing our capacity.