pic: Recycle Rush Re-design Part 2

[GeeTwo]

Originally Posted by Ari423

We went the pneumatics route this year, so I have some first hand results as to how our testing went. Not powering the downstroke sounds like a good idea until you learn that most solenoids need 20 psi minimum on each side to open and close properly. We eventually decided on 15 psi, and it was still very slow going down.

I agree that powering the down stroke with 15psi is probably worse than not powering it at all, but relying on a spring return or (if there's enough weight) gravity. Alternately, the two sides of the lift cylinders could be controlled through a 3-state solenoid or controlled separately so that you don't need to fill the upper chamber of the cylinders to 60psi, even though the supply is that high.

Originally Posted by Ari423

Also, don't forget that once your tank drops below 60 psi, you will see decreased performance. For this reason, we went with slightly bigger cylinders at 30 psi so we wouldn't see that effect until later in the match. No matter the size of your air tanks, at 60 psi you will see that effect halfway through your lifts.

Yes, if you read more closely you can see that I was calculating based on the air in the tank above 60 psi.

Originally Posted by Ari423

Also, if you did what many teams did this year and let the second tote fall into the first one without lifting the first one, you will only need to lift 4 totes per 6 stack, not 5. You also won't need to lift them as high, only from 1 tote high to above the chute instead of from the ground. IIRC that's less than 25". Or you could do what we did and build a ramp attached to our stacker for the totes to slide to (almost) ground level, then you only need to lift the height of one tote.

That would make it even better on several counts - fewer than half as many lifts, as well as a lighter peak lift. The lift would have to be more than 25", however. Each six-stack would involve lifting 6 totes about 30", which is much less than lifting 15 totes 25". With a bit of optimization and some sensors, I estimate that five six-stacks would take about 3 gallons, or 3 six-stacks would need about 2 gallons of tank.