DR4B Roller Placement, Tower Takeover

I’m considering building a DR4B with a claw very similar to this.

To reduce the time spent on moving the DR4B up and down just to pick up a cube, I want to put rollers somewhere on the claw or on the base so that I can just drive forward and have the cubes go straight up the claw/tube (I’m making the claw expand so that it can hold 6-10+ cubes). I also want the rollers to straighten the cube if the robot comes in at an angle, and to ideally have the rollers use only one motor. How should I build the rollers, where should I place them, and do you think I could do this with only one motor?


Did you try building and prototyping your ideas?

1 Like

Yes, we can’t help with everything.

It is certainly doable to have horizontal and vertical rollers on both sides with one motor, but your system would inherently have a lot of friction and need a lot of torque.

A lot of this sport (yes, Vex was declared an eSport) is prototyping and finding answers on your own.

So you want vertical and horizontal movement correct? If so, could you just angle omni wheels (preferably the smaller ones) 45° And once a cube is intakes horizontally it will start pushing the cube up assuming there is a hard stop behind it.


One way to do this is to have a ratchet on the “clamp” motor or “claw” motor. You would need bevel gears however and I’m not sure how exactly you would link the rollers on the claw because the claw would open and close.

Basically, the claw would open actively and close passively while the rollers move in the direction that the motor moves. You probably would need chain somewhere. I have an idea for the claw but it would limit it’s range of motion. Basically, only the front face would open and close instead of the front face and sides of it. This would allow you to link the rollers directly to the motor and ratchet an opening and closing mechanism.

This can get very complicated very fast. Just an idea though.

1 Like

@NightsRosario No, I’m just trying to get an idea on how I could do it when I start building.

@Gameoa Ok, thanks. I think I get what you mean.

@mvas Thanks for the idea, I’ll look into it.

This topic was automatically closed 365 days after the last reply. New replies are no longer allowed.