pic: 114 2 speed Gearbox



Well, here’s the box that goes with the CAD drawings I posted. Twp speed dog shifter, output speeds of 5 and 15 fps. Middle wheel of a 6 wheel is direct driven to the center wheel, with chains running the others.

The only components that aren’t present are the pneumatics and their plungers.

Comments and questions encouraged.

Out of curiousity, where did you buy the pinion gears that are mounted to each CIM?

The pinions are the pinions from the previous years KOP, also available from AndyMark in the same size, only de-hubbed.

I love how you use aluminum hex stock as your gearbox spacers. Also, I’m guessing you’re using this gearbox to direct drive your wheels, right?

Nice and shiney, I like it. I look forward to seeing that gearbox attached to your acual robot. I looks like it would make for a strong drive train.

Doesn’t that make them illegal as per <R28>?

<R28> COTS ITEMS that are generally available may be used on the ROBOT. COTS ITEMS from
ROBOTS entered in previous FIRST competitions or COTS ITEMS that are no longer
commercially available may be used under the following conditions:
° The item must be unmodified, and still in its original condition as delivered from the
VENDOR
° The item must not be a part custom made for the FIRST competition and provided in a
previous FRC Kit Of Parts (e.g. 2006 FRC transmissions, custom-made motor couplers,
custom sensor strips, IFI CMUcam II modules, etc. are not permitted)
° The item must satisfy ALL of the rules associated with materials/parts use for the 2007
FIRST Robotics Competition

Specifically, it doesn’t satisfy the conditions set forth in the second bullet, given that the gearboxes from which it came and their components were made for FIRST.

If so, at the very least, it’s an easy fix. The gears available from AndyMark lack only the hub and set screw but are otherwise the same, so it’s a quick switch. Hold them in place with some 5/16" self-locking retaining clips and you’re in business.

Looks good. What’s the weight with the motors and piston?
I also can’t figure out where the chains are supposed to go. I should probably go take a look at your model again. :wink:

You can buy those pinion gears from Boston Gear (with the hub), so it shouldn’t be an issue.

Provided you key them somehow, this also a viable solution.

In any case, the gearboxes themselves look good. I like symmetry in design a lot and most gearboxes seem to be asymmetrical.

I thought about this… not sure what we’ll end up doing about it.

The middle wheel will have two sprockets on the sides of the wheel, which will run chain to the other wheels. See here: http://www.chiefdelphi.com/media/photos/26243

I bought 14T gears from Motion Industries. I also bought an 8mm reamer and a 2mm broach set to modify them to the CIM.

It Looks Sweet. What are the gear ratios?

I like how you faced out the inside of the gearbox plate :slight_smile: How heavy is it?

The total weight for the whole assembly, with motors and shifters and all that is too heavy… 10 pounds too heavy, to be exact.

But I’m really happy with the performance. It shifts nicely, with a small quirk on the left side (we’re fixing that in programming).