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3 Stage. I guess 2 Stage as well though, since they are similar

Iā€™ve built the 2 stage with a slightly different design but the same rigging. Worked great for what we needed it for, 3 stage should be the same as it is just another setup of the rigging.

ah, Super Cool. Those WCP Bearings are super nice, we ā€˜assembledā€™ a few last night.

Iā€™d love to see photos/videos of your elevator if you have them!

Unfortunately I canā€™t seem to find any, but yes the wcp blocks are sweet.

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Just out of curiosity, what is the design around that 2nd axel turned by the pulley?

the spool turning the chain seems to be driven off the main axel off the gearbox, but it looks like that other assembly is some paring of 36T HTD Pulley to a 20T Pulley(?). A little confused by this. Wasnā€™t sure if the design of this was to create some sort of auxiliary output shaft or if theres something missing in the CAD that runs off that 2ndā€™ shaft

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Thatā€™s just one way to mechanically link the power between both sides so they donā€™t go out of sync, which can happen mostly due to uneven loads. This way if for any reason more force acts on one side of the elevator, the force is spread out evenly between the motors and the elevator reacts uniformly.

We built a wide arm in 2023 where the two sides were not mechanically linked, so the end effector would sway with how the robot moves. Big lesson learnt.

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aaah! my bad. that makes a ton of sense! Thank you for the response.

Ofc, it was a great question!

only other thing Iā€™m a little confused about in that design, is the usage of the two 20t custom pulleys (not even sure where to find this) with the 36t HTD belt. Iā€™m sure theres good reasoning behind doing that. just not sure why

Designing for COTS Iā€™d use a pair of gears to get the same packaging, but if you can print the pullies and use a beltā€¦ belts are much better in low speed high shock stuff like this, where the load is well distributed across many teeth and damage is ā€œthe belt skipsā€ rather than ā€œthe gear tooth shredsā€.

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ah okay. We could 3D print the pullies, assuming your talking printing in plastic and not some sort of metal printing

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Hi! Silly question - why is the motor hole here 1.625"? I just wanted to understand the decision-making behind this - thank you!

This is from 1C, Exercise 6.
Screenshot 2024-11-05 at 10.27.57 AM

This is for weight savings, as it isnā€™t necessary to make the motor boss be a tight fit in the hole. It also allows you to slide the whole pulley assembly out through that hole.

With older motors that only had 2 holes, it was best to make the hole in the plate the same size as the motor boss (little part that sticks out from the face of the motor) to ensure proper alighnment. With modern motors that have more than 2 holes, you can use the holes themselves to ensure proper alighment rather than the motor boss, making assembly easier for you.

TL,DR it is personal preference, but there really isnt any advantage to making that hole smaller.

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Thank you :smile:

This belt is a bit thinner than id use for high load applications in all fairness.

Is that the kevlar from the belt?

Those are the teeth ripped off of our shooter pivot belts

Donā€™t know the rest of your mechanism but that pulley seems pretty darn tiny for pivoting a shooter assembly.

This is true. However, I did not design it soā€¦ It did work quite well till this happened, which was a couple months after competition season

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