Mounting encoders on a Clamping Gearbox (VEX)

Hey,
We plan this year to use VEX’s Single Reduction Clamping Gearbox

I was wondering how can I mount an encoder on it?

When you make the axle , include a stub on it to attach the encoder to. Generally speaking, most encoders can attach to a .25" shaft.

That’s still a little tricky on that clamping gearbox with any adapter plates or anything. If you were trying to use one of the US Digital mini encoders, you’re be trying to mount it on the shield of the bearing. (Which I have seen attempted before. I explained that it wasn’t likely to work very well).

I think you’re down to getting the VexPro Shifter encoder kit or the Andymark Encoder package or Mount Pad and drilling/tapping or gluing to get them attached. If you’re using a kit with one of the US digital mini encoders, I’d encourage you to get the centering tool directly from US digital, so you can make sure the encoder is centered on the shaft.

Are you using this for a drivetrain application ?
If so, What ratio and wheels are you using on this gearbox ?
Seems a bit fast if you are using 6 inch wheels

Agreed.
There were many details that were left out in the original post and in my reply. More details are needed to give a complete answer.
Suffice it to say, there doesn’t appear to be an off the shelf solution. Some custom manufacturing will be needed.

The DiscoBots are using clamping gearboxes this year on their drivetrain.

The team has generated a couple ideas on how to mount an encoder to the gearbox.

http://2015.discobots.org/node/16

We are using this for our lift gearbox setup since it easily incorporates a disc brake directly onto the gear. The encoder will go into the end of the shaft, just like it does in many WCD drive trains.

  1. How are you incorporating a clamping gearbox in your lift ? (i.e. what reduction are you getting off the gearbox)

  2. Do you have a picture of the encoder at the end of the shaft for WCD drivetrains ?

1.) The lift is 11:72 -> 16:22 (chain) for a total reduction of 9:1 coming off a CIM. We have other options, including smaller sprockets, bigger sprockets, and/or a mini-CIM depending on how the PID response goes. To me that’s what makes this particular gearbox very versatile.

2.) I’ll snap a photo of the WCD shaft tonight, but here’s a description until then. I gave this problem to our machining team in the preseason and they came back with something I haven’t seen, but it is something we’re very comfortable manufacturing in-house. We took ~4.5" of VEX Pro Hex, turned down a shoulder on one end to 3/8" and put it in a die for a 3/8-16 aluminum nut. We then bored a drill bit ‘D’-size hole in the same end for a very nice snug fit of a Greyhill 63R encoder. The other side is tapped 1/4-20, 1/2" depth. Locktite all around.