Using the WCP PTO without a transmission

FIRST General Forum
1

There was a question in another thread about how to use the WCP PTO, and I got a few pms about it. So here are a couple pictures showing how we used it.

The product:
https://www.vexrobotics.com/217-3636.html

We actually used the product as the rear axle on our drive train :

A picture of how the product is assembled. The aluminum C was just some box tube we had laying around:

The chain leads up to our winch. We used the other side of the robots drive train the same way, but we extended our safety legs with it and ran it at a different speed.

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2

So with this setup, are you restricted to running the chain outside the frame perimeter or can you still do a traditionally wcd with the chain inside the frame perimeter?

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Thanks Tom, this is really useful.

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You could definitely go with a chain inside. You just need a bigger C piece to give you the room on the shaft.

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Is there a CAD file just for the PTO. I can find one attached to the WCP 3-Cim Dog Shifter but not one just for the PTO.

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The product link in the OP has a CAD file in it.

7

My bad, I was on WCP website

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I don’t have a ton of experience with dog shifters, and I’ve only ever seen them used with dog gears, which have the teeth/cutouts machined into them to engage the shifter. I couldn’t tell from the pictures, is your shifter engaging directly into the sprocket? In other words, what do the teeth/cutouts on the shifter engage in?

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Shifted in one direction they don’t engage anything. In the other direction they engage in the plastic disc shown on the axle on the product page.

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Ah that makes more sense. We’ll definitely keep this in mind in the main season. Previously we’ve ruled out any sort of PTO because of complexity, but a COTS solution is fantastic.

11

Did the plastic disc wear over the course of the season and if so, how badly?

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