Refining our DR4B

Ah okay.

Right now we have a c-channel across the entire midsection keeping it together, a cross-brace across the middle towers to keep the DR4B moving as one unit, and standoffs connecting the bottom of the towers, but not going across the entire mechanism.

I mean the two half c channels that have the gears between them should be attached (a standoff or c channel should work). Sorry if I was a bit confusing.

Oh whoops I think I replied kinda awkwardly. We do have a standoff going between them and a c-channel across them but only at the very top and bottom.

Ok. That should probably be enough. It was most likely just the spacing then.

There’s a 99.5% chance that the bars are angled because of the square holes. Take a tape measure to check the distance between each bar all the way up each half of the midsection and if there is a difference between the top an the bottom, loosen all the screws connecting them slightly, realign them, and get a friend to hold them while you tighten the screws again. This is probably just another vex square holes ftw situation.


Okay first off I just want to say thanks for the screw+standoff idea and using the kep nut to keep the screw straight because those really helped lessen the slop in our DR4B. Now the only problem we have is our 4 bars are too close to each other so now they hit each other when we go up and down. We’re hoping that putting a brace across the bottom 4 bar will help with that though.

Do you mean the two linkages on each half of the lift are hitting each other or the two halves of the lift are hitting each other?

Um I think I mean the two linkages on each half of the lift are hitting each other. I can send a picture of it to make sure we’re talking about the same thing?

Also since they’re too close I can’t put rubber bands on both sides of the lift arms rip.

I think a picture would be very helpful.

Here are the pictures of the area in between the two 4 bars. Not much space in between them…

IMG_20190613_230406 IMG_20190613_230429

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It looks like the screws are the only things that are touching the other bar, and you can file that area slightly.

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Yeah normally they don’t touch but when we go up and down the DR4B will sway side to side and clip the left side. We’re hoping that bracing the top and bottom will alleviate that though.

Bracing it should fix the problem. You also might want to try tightening the joints slightly so it doesn’t wobble as much.

Yep bracing the bottom and top 4 bars really helped and now it goes up and down pretty smoothly. Thanks for all the help!

No problem! Let me know if you have any other problems with it.

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I have a concern with your robot: all of its wheels are omnis, so people could just push you sideways.
But then again, I’m probably hallucinating from those shrooms I ate earlier lol


Um well they are omnis but I’m not sure why being pushed around a little bit is a big problem? Scoring is mostly in protected zones anyways.

I mean sideways, since all your omnis are pointed forwards, they are able to freely slide sideways, which is why some teams use so called bling wheels

Unless of course you already have a mechanism to stop that

Well yes they are all pointed forward but we’re not planning on blinging our wheels either. I don’t see the problem with just leaving our wheels as they are?

My team used bling wheels on one of our robots last year. They slowed our drive train down slightly with the added friction, and we were still able to be pushed around by robots with strong drive trains.