pic: 0399 Teaser

Does this thing do two drive speeds and PTO with one shifter? This is beatuiful, and I can’t wait to see the final robot.

I know this is a teaser, so you probably won’t give out much info, but is that a three stage shifter? I see three ports on the low profile pneumatic cylinder and four gears on the shifter shaft. I am very intrigued by this design and would love any information you are willing to share!

If you are using a 3-stage cylinder, apparently it has very little force it has in the middle position (<10% of full out/full back force).

I think the 3 position cylinder is for selecting hi-low speeds with pto in the middle/neutral position…

Yes, 3 stages, 1 for PTO.
Madison on FB pointed to a multi-position Bimba Pneumatic cylinder and that appears to be it. I bought a few for future use but mines havent come in yet. They are very pricey.
You can see the 3 input fittings also for the 3 air lines.

That makes sense, but the PTO has a lot of force on it and if it slipped the results would be catastrophic (presumably). Have teams used these in the past for PTOs?

As far as I know, only to put the drive in neutral, with a separate shift shaft engaging or disengaging (or even locking) the PTO.

That is a neat gearbox.
Can you show us a picture/diagram of how you plumb/connect the actuator to a solenoid?
I have always wondered how to connect these actuators when most of the solenoids we use have 2 supply ports (A&B). I haven’t been able to find 3 port.
Thanks and good luck.

We utilize 2 solenoids per gear box, one for high/power take off and one for low gear. If you need more info feel free to ask.

I guess I’m still not sure how that would work.
You now have A1&B1 and A2&B2 giving you a total of 4 ports from the solenoid but with only 3 ports on the actuator.
If you can explain how that works that would be great.

So how do you reconcile the extra port?
A1------Actuator port 1
B1------Actuator port 2

A2------Actuator port 3

Thanks again.

This catalog page shows which ports should be pressurised and which should be vented for the different cylinder positions. We’ve found that it finds the intermediate position (Position 1 on those figures) a little better when ports 1 and 3 are both pressurised (since otherwise the second rod can float). Using this, we made a table of desired cylinder position and the desired port states for each (1 for pressurized, 0 for vented). Visual inspection of this shows how to plumb the solenoid valve to achieve this (and whether you need a single or a double, which way is the default position, etc.). If there is a valve port that is not used, it should be plugged to prevent venting the entire system when the valve is actuated.