My team was planning on pivoting an arm with a Neo’s to manipulate the game pieces. We are looking for a planetary gearbox set that can get a high ratio with not many sections or a small gearbox. We were looking for around 500:1
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MaxPlanetary.
NEXT!
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On a more serious note, don’t connect the MaxPlanetary directly to the arm, have an intermediate chain and sprocket reduction and your life will be much better.
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Could you please elaborate?
It’s a good idea to use a chain and sprocket as the final reduction stage from a gearbox to driving the arm joint. The reason is that the arm can experience large external torques due to shock loading (e.g. the arm hitting a wall) and sprockets are much better than gears at handling shock loads, because you have multiple sprocket teeth engaged and therefore sharing the load, versus a single gear tooth taking the entire force (snapped gear teeth in this situation would not be unusual if you didn’t use a chain). The chain slack also can absorb some of the instantaneous loading and smooth it out before it hits the gears in the gearbox.
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I cover this and more in this post about high torque arms:
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In case @Nick.kremer’s post wasn’t totally clear, a key advantage of the chain drive is that you can BOLT it to your arm and avoid asking the hex to carry all that torque.
See the HowdyBots awesome vacuum flip climber for a stellar example of a chain driven arm-thingy with VAST torque!
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Definitely do as the others have suggested and attach the big sprocket directly to the arm. One of our local teams used 1/2" aluminum hex shaft as a live axle to transmit the torque for raising their 4-bar arm in 2015. It twisted along its length. When they scrapped it, they had to cut the shaft next to each bearing and hub to get them off.
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Thanks for all the feedback. We will definitely design with it all in consideration.
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