pic: FVC 2013 Gear shifter

[gdo]

[cdm-description=photo]28489[/cdm-description]

[Jeremiah Johnson]

Awesome, but how does it work?

[sanddrag]

It would appear that a servo causes the little linkage arm to rotate which in turn forces the center shaft to slide axially, engaging either a smaller or a larger gear with either a large or small gear on the motor shaft, while maintaining mesh with a triple wide gear on the final shaft.

Nice work.

[fredliu168]

wow, no wonder you guys were first pick =P

[Synergy1848]

looks alot like the one we used except that we shifted with a rack and pinion set up.

[fluffy]

solid...I like the design

[psyco_klown]

Nicely done! Hope to allience with you again. They have a great robot every year. Cant wait to see what you guys do next year.

[cire]

I am amazed, very compact and clean design. My own shifter used 1 servo on each side, and doesnt seem as solid as that one. nice work!

[gdo]

it actually uses a MOTOR, not a servo. even though this type of action is almost perfect for the servo, they don't have the torque to perform the action, we learned this early one, so used a motor with some gearing. The gears for shifting are beveled which gives a cleaner shift, I have some more rendered photos. All parts were made by my team in Maya 8. The shifter has a 3:5 and 5:3 ratio.

Update: I am posting some more pictures, and gather documentation on the shifter design. It should be posted on our site at http://eaglevex.syraweb.org in a day or two depending on how quick we gather the info.

[VEN]

I am SO trying this

[Qbranch]

VERY nice design... but I have a question...

did you guys bevel those gears on a lathe or did ifi (vexlabs) start molding beveled ones? Also, did you use a shaft encoder/limit switch to decide if you were in gear or not?

again, sweet shifter.

-q

[Donut]

Looks good, the shifting design reminds me of the shifter I tried last summer. I like the slotted shifter idea, I think I'll have to try that out in the future.

The transmission write up says your team tried a few previous versions of this shifter in the design phase. Did you always go with this design and just create improvements, or were there some other 2-speed designs (shifting mechanism or meshing system) that were tried?

[psyco_klown]

they bevel the gears themselves by some sandpaper and a drill

[gdo]

We got the information posted on our shifter.

It can be found here: http://eaglevex.syraweb.org/GearShifter.htm

Some prototype designs can be seen here: http://eaglevex.syraweb.org/MiscSummer2006.htm

And the robot can be found:
http://eaglevex.syraweb.org/QCC2006.htm
http://eaglevex.syraweb.org/Hartford2006.htm

For the shafter encoder, it is placed on the "block gear" (three wide gear) and it worked very well in autonomous. Hope our post on our site helps with any question, if you have any more question, you can PM, AIM or MSN me.

~Team Unlimited, FVC 2013

[Chris1270]

You think you can seed some plans of the Gear Shifter.

[JesseK]

Thanks for posting this. I came up with a 10" wide version of this for a single side and couldn't figure out how to get it down to 9". Going length-wise just might be the key depending on the game and the robot's necessary manipulator clearance. Unfortunately with this design, it's not very plausible to add another 1-2 motors to each side without adding an entire new shifting mechanism.

If I ever get my current concept idea done I'll rebuild the old (10") design and show you what I mean -- 3 motors per side and it could push 40lbs of books across my carpet if I pushed down on the back of the bot with my finger for traction. (5:3 High and 1:6 Low)

[gdo]

This design is relatively compact. It is 1" wider than a square robot, and the same length as a square bot.