pic: Recycle Rush Re-design Part 2

[mman1506]

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. 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.

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.

Why didn't you just leave a port on one side of the pneumatic cylinder open and put a plug on the unused port of solenoid?

[GeeTwo]

Originally Posted by mman1506

Why didn't you just leave port one side of the pneumatic cylinder open and put a plug on the unused port of solenoid?

That would be "leaving the downstroke unpowered", which has been considered and largely discarded. Unless you have a separate mechanism to engage and disengage from the tote, your downstroke will have to work against some sort of spring action to get around the top edge of the tote. For reliable action, either the down stroke needs to be powered, or a spring return is needed, or the carriage must be heavy enough to force through the ratcheting action.

[Chris is me]

Originally Posted by GeeTwo

That would be "leaving the downstroke unpowered", which has been considered and largely discarded. Unless you have a separate mechanism to engage and disengage from the tote, your downstroke will have to work against some sort of spring action to get around the top edge of the tote. For reliable action, either the down stroke needs to be powered, or a spring return is needed, or the carriage must be heavy enough to force through the ratcheting action.

Depending on the design, this can be pretty trivial. Hinge-style tote lifters have nearly no resisting force in the opposite direction and if the weight of the carriage alone doesn't do it, a tiny amount of surgical tubing would.

Powering the lift in one direction and only lifting the top 4 totes reduces the number of powered strokes required to stack to 4, with half the travel of lifting the bottom tote as well. It is also probably much faster to do this as it takes a long time for a tote to settle on the bottom level. I would have to run the calculations for air consumption but this could make 3 or 4 stacks with a reasonably small amount of air; several Clippard tanks would do it.