pic: coupling for dual cylinder ballshifter

[AndreaV]

What's the reason for making this?
Need more oomph to shift, or maybe multiple positions?

[cbale2000]

Originally Posted by AndreaV

What's the reason for making this?
Need more oomph to shift, or maybe multiple positions?

How would you accomplish more than two positions with two cylinders? If they have different strokes, won't one just fight the other (not to mention cantilevering the coupling)?

If this for extra shifting power though, I would like to know what application it's being used for that requires a second cylinders to accomplish.

[EricH]

Originally Posted by cbale2000

If this for extra shifting power though, I would like to know what application it's being used for that requires a second cylinders to accomplish.

Betcha they're trying to shift a winch from windup to FIRE! and one cylinder wasn't cutting it. That was a pretty hot topic of discussion a week or two ago.

[donkehote]

Originally Posted by EricH

Betcha they're trying to shift a winch from windup to FIRE! and one cylinder wasn't cutting it. That was a pretty hot topic of discussion a week or two ago.

Paul Copioli said it would theoretically still neutral with a 400 lb winch, but so far as I know, no one has actually tested this yet. I would love to see some video (or at least pictures) of someone using the standard piston and having it NOT neutral.

[tag_groff]

Originally Posted by donkehote

Paul Copioli said it would theoretically still neutral with a 400 lb winch, but so far as I know, no one has actually tested this yet. I would love to see some video (or at least pictures) of someone using the standard piston and having it NOT neutral.

we were doing it with only a single piston at 60psi. we ended up having to up our regulator to even test. That is why we added the second cylinder. It works marvelously.

[IceStorm]

Don't suppose that you would be willing to share the cad files for this. Or offer to print another one for a small price? We were having the same issue last night testing our winch.

[tag_groff]

Originally Posted by IceStorm

Don't suppose that you would be willing to share the cad files for this. Or offer to print another one for a small price? We were having the same issue last night testing our winch.

https://www.dropbox.com/s/4mveor2l36...oupling.SLDPRT
just print 2 and they mesh together

[Cash4587]

Do you care to share the mounting plate as well?

[Jon Stratis]

How much force are you putting on this? Our winch uses a 2-CIM Ball shifter as well, and we were able to shift it under competition-load from our catapult (we haven't fine tuned it yet, but it's close to where it'll be) using only 20 PSI!

[Nathan Streeter]

Looks like a great and innovative solution to needing more shifting force! We had never thought of using multiple cylinders to increase shift force (just upping cylinder size or adding a lever... neither of which work with our space constraints). I didn't notice a ratchet visible on your gearbox... is there one somewhere in your design?

We had designed for a dog-shift method and tried modifying the tooth geometry (grinding the surfaces on the dog and the dog-gear down slightly so that they're still parallel but no longer parallel to the axis of the shaft), hoping that would take enough of the friction force out. Alas that was unsuccessful, and using our standard .75" bore shifting cylinder we couldn't pull it out even at 100psi. I suspect this method would work eventually, but might not be as repeatable... Instead we've decided to "cut our losses" and switch to the ball-lock shift method.

I saw 2177 just commented that their ball shifter (2 CIM input?) worked fine with only 20psi of pressure... have other people also already tried the ball shifter for their winch-release? If so what're your findings? What's the torque on your output shaft (force * spool radius)?

[Jon Stratis]

I'll let you know what the torque is as soon as we get the 110lb fish scale we ordered from Amazon over the weekend. Less than $20, and it should help us make sure our catapult is calibrated the same every time we hit the field. (We didn't think the normal 20-40lb scales some of our friends have would cut it.. the fish here generally aren't bigger than that!)

Oh, and it's a 1-CIM input currently... we didn't want to go for 2 unless we need it.

[theawesome1730]

We can shoot ours by hand after we added a lever arm to a custom dog gear. Your design looks so refined and professional. If I didn't know better I'd have said it came from vex

[IceStorm]

Originally Posted by Jon Stratis

How much force are you putting on this? Our winch uses a 2-CIM Ball shifter as well, and we were able to shift it under competition-load from our catapult (we haven't fine tuned it yet, but it's close to where it'll be) using only 20 PSI!

Were using quite a bit of force on ours. We had it working when using the high gear where it had to push the cylinder out of place but when we switched to using the low gear it didnt have the force to pull it free. our goal was to be able to pull it back enough to shoot from about 18 ft or so.


thank you for sharing the file. trying to find a way to get it printed out now is the next big challenge.

[AndreaV]

Originally Posted by cbale2000

How would you accomplish more than two positions with two cylinders? If they have different strokes, won't one just fight the other (not to mention cantilevering the coupling)

Ah right, you can accomplish two different positions with two cylinders, but not if it is mounted to he same coupling. Yes, if they were different length strokes it would probably just shatter the coupling.

Long day of troubleshooting, must sleep.

I am surprised the ball shifter would need a 2nd piston based on Paul's (theoretical) math, but the extra help won't hurt and it's still nowhere near the force needed for a dog gear. Much more compact than a big bore cylinder and a lever arm!