Weight is important, but also how that weight is distributed on your mechanism has some impact as well. For example, if you have an intake with a motor all the way out, you can move that motor closer to your pivot which reduces your moment.
For your kind of mechanism, I would recommend pneumatics if you’re already using them somewhere else, pivot as you’re doing if you’re not using them. Our general team rule is if we can find 3+ places to use pneumatics, we’ll add them. It’s become a lot less of a weight issue now, but it’s still irritating to manage.
Hard/soft stops can also be your friend if your gearing is set and you need a good way to support it. It doesn’t work nearly as well as doing PID on a motor to hold it up, but a hardstop at the end of the mechanism’s travel can often fix a lot of issues in a pinch. Just consider that you don’t want to be driving the motor into the hardstop. In 2019, we had a preset for our elevator that was 2-3 inches higher than our elevator could actually go, and we definitely stalled a couple motors before we figured out what the issue was.
As a frame of reference, I designed an intake mech similar to yours and weighed it at 4 pounds in CAD. Using a weight of 20 pounds is overkill(ish). I can’t really say exactly what yours weighs, but there are some certain ways you can reduce weight as well:
- Switch solid aluminum to lightened polycarbonate/Lexan (half the weight, much better for high impact areas)
- Switch bearings to TTB bushings or similar - most intakes aren’t handling a load that high to always need hex bearings (though your use case may need that)
- Using captive shafts, retaining rings, or tapping end (shaft collars are heavy)
- Using a pulley/gear reduction instead of using a VP/Sport. Usually custom reductions or custom gearboxes are lighter unless you’re gearing something down a lot.
Overall, gearing is one of those things that is a lot of rules of thumb. Design informs functionality, so making things lighter in the design process means you don’t have to gear down as much, and your mechanism can rotate faster.