Lift Questions

At a recent competition, our axle candy-caned when one side of our lift stalled while the other didn’t (bad driver got stuck on the fence, we had to rotate drivers due to coach). Along with this, the axle snapped so we were a push bot for the rest of the competition.

I have seen other teams directly gear their lift, as in they geared the motors, and that rotates the arm.

I have also seen other teams use a sprockets & chain to rotate their arm.

Would this (sprocket/chain) be a safer option/prevent candy caning? Would this prevent the hanging of a robot that is about 17-ish pounds? Is it better to have two separate bars for the lift or one c channel?

Note: I am not demanding for an answer, but it would be nice to have some advice, everyone on my team is split and none of us have been into robotics for more than 2 years.
The first 3 pictures belong to 338T/Turbotech the last one is a picture of my team’s lift, the gear (36t) has been replaced with “lock plates”/“lock bars”.
2017-02-12 (1).jpg
2017-02-12 (2).png

Also, we are disassembling the lift. Putting all the weight on one axle was a bad idea, we will separate it next time. Plus it is useless right now.
Edit: Basically, old design bad, looking for better concepts/ideas to put into a new design. Candy Canes are now our least favorite candy.

There’s too much space between the towers; you need more support for that shaft. I would also recommend moving to high strength shafts; the low strength shafts don’t really cut it for such high loading, especially in the way you have built it.

put the bars for your lift directly on the 60-tooth gears. If the load is in the middle, and the sources of power are on the ends, then your gears could skip easily. Also, use aluminum if possible.

A word of caution - 3388T (I believe) uses the sprockets for their extra “oomph” catapult when they release objects. I wouldn’t recommend using sprockets for a lift, although I can’t think of a specific example of that going wrong… I haven’t tried it because it just seems like a bad idea to me, and gears are fine.

The shaft in the middle is very bendable. The gearboxes on the side are okay. Try attaching your lift to gears in the tight, outside gearboxes like on this (old robot pic):

If the axle that is bending is not connected to a motor, you could stop it from moving entirely by using one of the square bearing blocks, and switching the inserts in the gear to the circular ones. Then, rather than the gear rotating with the axle, the gear rotates around the fixed axle.

the last pic looks almost exactly like our lift

As a few other people have suggested, try attaching the lift directly to the gears by screwing the c channels to the gear. As a general rule of thumb, try not to power anything through an axle, other than of course the motor, as VEX axles are very prone to twisting. I would also not suggest directly powering your lift, as that won’t provide enough torque for what is usually needed this year.

Thanks for the feedback guys! :slight_smile: