We need help with our robot

Ok, so my team has a pretty major issue for which we need a solution…

Our method of lifting the Mobile Goal uses a motor connected to a square shaft (which is inserted in a bearing flat) turning and lifting our mobile goal. However, the square shaft is shaped according to its name, and the bearing flat has holes that are circular. Thus, our motor (and square shaft) just spins without actually doing anything. We found a plethora of designs that were gear-less and featured a design similar to our own (except, when their motors turn, they actually gain traction). I have attached pictures of our dilemma to this post, and I would like some feedback regarding what can be done to solve this issue.

A note: we really don’t have any idea what we’re doing. This is our first robot as a team, so we are trying to experiment.

Thanks in advance!
Sidney, University Prep Vex Robotics Team

I don’t see any pictures. But, if you are talking about the shaft spinning freely instead of actually catching on mechanism causing it to move, that is not what bearings are for. Bearings are only for reducing friction when shafts are moving through c-channels. If you want to do a gear-less design you need to use Lock bars.

You can screw these on and insert the shaft through.
They can be found on the shaft hardware page:

Or use a gear to mount the axel to the piece of metal that you want to move

a bearing’s purpose is so the shaft can spin freely in them. if you want a bearing-like piece, but with square holes rather than circular ones, you can use lock bars. or, if you have none, you can mount your lift to your shaft with a gear.

its hard to imagine what you’re saying without the actual pictures but if you really want the shaft to not turn (which presumably means you dont want the gear to turn either) couldn’t you just screw the gear into the bearings?

@Vyx I think they are trying to get the mogo lift to turn with the shaft, but they just have the shaft going through some bearings on the mogo lift, and it isn’t turning w/ the shaft

Easy solution: Just dont lift the mobile goals. Launch them. The best design currently used on the VEX Discord is a mobile goal catapult which launches them into the 20 pt zone. this allows for 1mgps (1 mobile goal per second)


If your mobile goal subsystem is not a Roman Ballistae, reconsider your entire robot…

pfft, my robot can take in two mogos and use one as the counterweight on my glorious trebuchet

This is ingenuity at it’s finest here. Worlds finalist, calling it