How to build a rd4b

My teacher restarted the monstrosity called a robot and now we need to build a reverse double 4 bar because nothing is good enough for him LOL… we have observed many pictures of them but have no clue of how they work or how they build them. So WE NEED B L U E P R I N T S.

Thank you in advanced your support has been amazing.

P.S - My teacher watched me type this…

Well not to be rude, I just doubt any team is willing to give blueprints. But here is a video of someone building one in inventor:

However as I said before I doubt anyone will give out actual blueprints. The point of VRC is to come up with your own design and that way not every robot is identical.

Yeah if you ever want to good in robotics you need to do so without step-by-step instructions. But there are too many robot reveals that you could copy the lift of if you really must.

This is a really nice video showing a very simple and clean DR4B. One of the teams I coached built a DR4B using this video.

Our robot v1.0 this season had a DR4B and one thing that made it really successful and reliable was that we had a LOT of cross-bracing from left-to-right sides of the lift. In the video above, you can see that it kind of wobbles as it goes up & down; you can easily improve the wobble problem with a lotta 1x pieces in “X” shapes. I recommend cross-bracing each segment (2 horizontal sections; 1 middle vertical section) in some way.

We also had rubber bands on the top & bottom sections of the lift, which were helpful to reduce strain on the motors.

No offense to your teacher, but it seems to me that it should be the student’s call as to whether a re-build is the right choice.

That being said, every other person here has already said my opinion, you just have to do it. There are lots of great examples online, but very few tutorials.

What do you mean by blueprints? Blueprints don’t really exist for whole systems, maybe for small subsystems. Definitely not in VEX though.

I believe what you WANT is CAD. There’s plenty of videos available of double reverse four bar CAD. You may also want to learn how to CAD using Inventor and the .step files that VEX provides on their website.

Additionally, nobody will just give you these kinds of things.

Now, onto rd4bs.

An rd4b has four main parts.
The pivots at the bottom, which are held up by towers and must be tall.
The lengths of your four bars. They must be the same length if you want your rd4b to be linear. (meaning it moves up and down in a straight line, which is very important).
How you’re transmitting power between the lifts in the middle.
Finally, how you’re powering it.

About the pivots at the bottom, you can either power it from there or power it from the “middle” of the rd4b or the bottom. It’s generally easier to power it from the middle. Usually, to transmit power between the top and bottom linkages, you use gears that are screwed into each c channel and maybe some idlers in between if your upper bar is not a 6 bar.

Okay so I see that some of you think that my team should do this without step by step instruction and yes your right but I’m sorry if this made you reply in a way that sounded rudely this was satirical but we have a member who knows how to build one of these

P.S. how do you delete a conversation.


My team is making a DR4B lift for this years competition and we cant find any good instructions for how to build one. We could use some help.


“Kepler Electronics” on YouTube is a good place to start.

yeah i looked at that it was very helpful :smiley: