Shifting Two Anymarks with One Pistion

As you all know, weight is a BIG problem, so much so we decided to go with an off board compressor. Witch lead us on a never ending search for ways to be more efficient. I know a lot of other teams are on in the same boat so we are more than happy to share the knowledge, GP!

pics -
http://picasaweb.google.com/john.h.842/OnePistonShiftingTransmissons#

Very nice! Innovation is always good to see, especially on the small details! (that means someone other than me is focusing on the details, hurrah!)

Did you use a piston with twice the stroke length?

Looks really nice!

How did you calculate the distance??? Guess and Check or with CAD.

That looks like a 1" throw cylinder… wouldn’t that be using about the same amount of air as two 1/2" throws plumbed together to one solenoid?

That´s what i was thinking. I guess you save the weight of an extra solenoid.

Nope, you can just T two cylinders off of one solenoid.

It would weigh less than two cylinders probably (Depending on the linkage weight), but I don’t imagine it would reduce air consumption like they claim.

Team 968’s 2004 robot was successful with this idea. Pic. I think it saves weight more than it saves air.

Of course! We did that on our robot this year. What was i thinking:ahh: … it must be late…

Team 45 was the first I know of to do this, in 2003.

you should check out and see what the total weight of this system vs. two 1/2" stroke cylinders would be. there might not be much weight savings - the small cyliners are pretty light.

Also, you can control them both from one solenoid (which is actually a good design approach so you know both transmissions are shifting at the same time).

You might also be cautious - it is not legal to modify the pneumatic cylinders, and some inspectors might be concerned about the modifications you have made.

48 also did this in 2003 on our 45-inspired dog-shifter design. We also added failsafe springs to force and keep the shifters in gear in the event of a pneumatic system failure.

Simbotics did this last year.

Guess & Check

Love it :slight_smile:

Team 716 has been using a single 1" stroke cylinder since the off season of 2003. The single cylinder generally locks in one gearbox before the other which can give some pretty interesting movements if you shift during autonomous!

We build an adapter to screw on the back side of the cylinder with a 10-32 screw sticking out to match the piston rod.

to save more weight and air you could use servos to shift:D

also i was thinking about somehow shifting two with on small motor if we get a small enough one in the kit?

I have to say, I’m not entirely a fan of shifting with servos. I would want my drive train to be the most durable, reliable, and least complex mechanism possible. The added complexity and small (easily breakable) parts of servo shifting makes me a little nervous. Now, I have to say: I’ve never actually tried servo shifting, but have done pneumatic to much success.

Anyone wanna weigh in on servos?

it saves more air for use because i think we used 1 inch pistons to shift in the past not 1/2

we used them on our 2007 robot and they worked good(not as well as the pnuematic shifting though)enough to allow the robot to do wheelies,

using servos would be less complex,I’ve never had a servo break before,

and you could probobly replace that piston with a single, small, motor(like the fischer price maybe) and shift both(dont know if this would work any better but the idea is out there now)