Currently i have a nice working tray with tilter sitting on a 16in by 16in mecanum wheel drive base. The base works well but the tray we had failed miserable. I am wondering if anybody could help with the two arm roller bars.
He’s the only person I’ve seen on the forums attempt it, but theirs didn’t really work.
Unless I’m misunderstanding what you mean. Do you:
a. Need both rollers to be powered by one motor, or
b. Need just one motor to lift up both arms?
It would be nice if you talked us through any thought process you had before asking the VEX Forum- it’s kind of hard to help if you didn’t have much of a plan to begin with.
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need one motor to lift both arms
Yeah just put both arms on the same shaft
If they are further than 12” apart you’ll need to use shaft couplers to make one long enough
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I’d place a C-Channel near the back of the arms (basically near the towers where they’re mounted), rough sketch below: (the proposed C-Channel is shaded in yellow):
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Having one motor for both the arm and intake rollers will not work as both subsystems need to move in 2 directions. I would suggest one motor for the arm (totally doable) and two motors for the rollers (one is doable, but does not provide enough power).
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I’m working on a 1 motor lift right now so I’ll tell you of anything I find
did you find anything from what i can tell in takes at lkeast a 100 rpm motor
Do you still need help?
help would be nice. currently I have a mecanum wheel drive base witha tilting tray and two intake rollers. so that leaves me down to one motor that is 200 rpm motor. currently what i need help with is creating arms for the intakes as the current position of mounting them next to the tray on the drive chassis seems rough. intakes and grips find although improvement be nice. we want arms so we can remove from towers. the other discovered issue is that it only has the grip and power to intake for cubs. intake motors are 200 rpm
For a 1 motor 2 bar (200 rpm) your gonna need at least a 15:1 ratio which is as close to a 7:1 (100 rpm) as you can get. That’s compound gearing a pinion with 60 tooth, then pinion with 36 tooth. The output of the gearbox moving the two bar has to distribute power to both arms evenly. Many teams have solved this issue by running high strength axles from 1 side to the other, and also bracing the two bar arms together using C-channel, half-channel, or standoffs with collars. A two bar is a pretty basic lift so there are a lot of different ways to build it that will work effectively. Just keep in mind building fundamentals to lower gearbox friction.
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that is helpful thx. one last question. the barrings don’t fit high strength so how does one use them. we have the standard barrings if there is one for high strength axles we don’t have but could get if need be. What is the solution to this?
also would the gearing look something like this
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What is this gear doing?
https://store.robotmesh.com/vex-robotics/structure/vex-high-strength-shaft-bearing-10-pack
They make a high strength bearing for this. Keep in mind out of the 3 different kinds of joints (hs, ls, screw) hs has the most friction, but it’s strength against torsion overcomes the disadvantage of added friction. Id recommend using lithium grease to lubricate those high strength bearings.
Gearing schematic looks good.
Is white lithium grease allowed? In the rules it says non-aerosol and that(wd40) is
I mean the rules are fairly clear about lubes imo. As long as it’s not aerosol based and you use it in moderation, its perfectly okay.
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I agree with the bracing part but, I believe, the better solution is to link 12T gears driven by the motors with an axle. Then have those 12T gears drive larger gears on both sides. When torque is smaller axles are harder to twist. Also you don’t need to worry about rounding out of the HS gears if you don’t have lockbars.
Yea he got the concept in his diagram. Use a regular ls for motor to pinion, and 36 to pinion. Hs for 60 tooth.
sweet thx! i have grease and will get high strength barrings and should be good. i will keep u updated if i have issues.
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