pic: 716 Dual Motor/Dual Speed

[CD47-Bot]

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[JulieB]

Wow NICE!

[Joel Glidden]

Nice work! Compact and attractive. It looks like all of your parts are do-able on manual machines. I'd be interested in seeing some more detail in the shifting mechanism. I'd also like to know what your reduction ratios are. I'd love to get my hands on your CAD drawings / models for future competitions. Thanks for the great photo.

[Collin Fultz]

looks good! it looks similar to what we are trying for this year and kind of like Kokomo's from last year, but also different and (i hope) improved upon. good work!

[Cory]

Joel: I modeled 716's shifting tranny, with the exception of the drill motor and it's gears. It is in Inventor, and if you'd like a copy, I'll send you one once I get home from school.

Cory

[Brant Bowen]

Oh yes, very nice indeed. I like how both the motors are on the same side of the gearbox, that should save a lot of space on the robot. If you don't mind, I was wondering about how much that assembly weighs?

[Joe Johnson]

Assuming I am understanding things correctly, I like the shifting yolk and I also like the tri-lobe drive blocks.

Can I ask a question? How much "back lash" do you have in your shifter? What I mean is how much angular rotation does can your last gear make with the output shaft held fixed and the shifter engaged?

I am curious because your design seems to have only a small amount and Andy (and others) have advocated having quite a lot so that the "dogs" have more room to engage.

But, generally speaking. Well done.

Joe J.

P.S. I am guessing that it weighs just under 4 lbs each without the motors.

[tkwetzel]

Very nice indeed. Looks similar to 116's gearbox, except yours is a bit more compact. How does the shifter work, it is unclear in the picture. Your mount for the drill motor is nice, looks pretty sturdy.

[sanddrag]

Another great design, Andy Brockway. On that shaft that is riding in 3/8" ID flanged bearings, is there a third small gear that is hidden in that picture?

[pras870]

peronsally I'm counting 10 seperate gears, but I could be wrong, I do have really bad eyesight when im not wearing my glasses!

[Cory]

Originally Posted by tkwetzel

Very nice indeed. Looks similar to 116's gearbox, except yours is a bit more compact. How does the shifter work, it is unclear in the picture. Your mount for the drill motor is nice, looks pretty sturdy.

that silver square piece with the chamfered corners does the same thing as the Technokat's "dog", but it does it without requiring CNC machining
. Basically, the final 2 gears you see are rotating freely around the shaft, since they have bearings pressed into them. What happens is when that square piece is moved in one direction, or the other, it engages the gear by going into a square hole on them. Since the silver square is fixed onto the shaft, when it engages the gear, it causes that one to also be "fixed" and allow it to transfer power to the output shaft, rather than spinning freely on the shaft.

Cory

[tkwetzel]

that silver square piece with the chamfered corners does the same thing as the Technokat's "dog", but it does it without requiring CNC machining
. Basically, the final 2 gears you see are rotating freely around the shaft, since they have bearings pressed into them. What happens is when that square piece is moved in one direction, or the other, it engages the gear by going into a square hole on them. Since the silver square is fixed onto the shaft, when it engages the gear, it causes that one to also be "fixed" and allow it to transfer power to the output shaft, rather than spinning freely on the shaft.

That's an interesting way of shifting. 116's gearbox has a gear specially made with a dog on it (use the lathe to cut down gear stock), but instead of a free spinning gear, the gear moves to engage other gears. Team 116's gearbox can be made without the use of a CNC, and this one looks the same way.

[CJO]

Have you checked out 223's transmission, it is similar in the free-spinning gears on a shaft, but instead of a sliding key, they have ball bearings which pop up from inside the shaft to engage the gear.

How are you moving the shifter?

[tkwetzel]

Have you checked out 223's transmission, it is similar in the free-spinning gears on a shaft, but instead of a sliding key, they have ball bearings which pop up from inside the shaft to engage the gear.

That would be team 222 that has that transmission. I agree that it is very sweet.