pic: Vex 2 Speed Mesh Shifter

[Winged Globe]

Very nice system. We also used a servo link when we built our prototype shifter for the spring Vex competition and it worked quite well. With only the starter kits, I think that's the way to go.

Originally Posted by Arefin Bari

From what I am looking at, my suggestion would be to add a pinion gear (bunch of vex gears together) to the shifting shaft (on the right side of the picture, you might have to make the width of the tranny a bit bigger), and then mesh it with another gear on a new shaft. Make the new (third) shaft the output shaft.

Matt, I know you are limited to one vex kit. This was just a suggestion. So far you have done a great job. I like the way it is coming out. Figure out how you are going to shift and you got yourself a sweet little mesh shifter. Can't wait to see what you come up with next. Good luck.

The material limit is definitely the hardest challenge. In order to accommodate the shaft movement, we vigorously ran a shaft through the center of an "output gear" to go on the shifting shaft. The gear was braced between the frame and another piece of metal. The shaft moved freely, and we didn't have any noticeable slipping of the gear. The output gear transmitted to a final wheel shaft on the exterior of the bot.

Why didn't it work? 1) We ended up needing all those gears for the arm, and we guessed that shifting would give marginal point benefit during the game. 2) We had a lot of shaft collars to make sure the gears didn't move, adding a lot of extra weight (though you may want to consider this if your gears get loose). 3) Plus, doing six-wheel drive by way of a nine gear gear train on each side in addition to the 3-speed shifter shot our turning efficiency to 0 (and again, no gears left). It worked wonderfully going straight, though... Haven't tried it with the sprocket and chain kit yet.

Can't wait to see your take on this (and with only 1 kit!).