Belt too long? Belt wont not always retract all the way

Troubleshooting
1

So I just took my M4 apart and I noticed the belt was rubbing against one of the shafts from the motor. I also notice that this motor tended to not retract all the way. I am thinking the belt rubbing against the shaft was increasing the resistance. How long should the belt be?

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j

2

@bar since you are getting the mould remade I’m curious if you designed in more clearance?

3

Bryan A wrote:

So I just took my M4 apart and I noticed the belt was rubbing against one of
the shafts from the motor. I also notice that this motor tended to not retract
all the way. I am thinking the belt rubbing against the shaft was increasing
the resistance. How long should the belt be?

That is normal, the belt is 14.5 ft long, the max that can go there. When it’s
retracted under tension it spools a little tighter.

check how the idler gear spins on it’s shaft, and see if the motor can be moved
away from the idler just a bit, then lube the spool and tighten the bolts that
holds the two halves of the arm together snug, but not tight enough to clamp on
the spool and prevent it from turning.

David Lang

4

Tim Seidlitz wrote:

@bar since you are getting the mould remade I’m curious if you designed in more clearance?

No, the change just puts bearings on the idler, it uses the same spool, and the
same gear, so they have to be at the same distance.

There is a patch in the queue for the firmware that will let you put a clamp on
the belt so that you can zero it without retracting it all the way.

David Lang

5

I put it back together and it seems to be retracting normal now. It did this before where it worked the first couple times and the later it would not retract all the way.

So you think this is due to friction in the idler?

6

Bryan A wrote:

I put it back together and it seems to be retracting normal now. It did this before where it worked the first couple times and the later it would not retract all the way.

So you think this is due to friction in the idler?

The common issues we have seen are:

  1. the motor is too close to the idler, they do not turn well
  2. grit/plastic shards get in th eidler and it jams on it’s shaft
  3. the bolts holding the arms together are too tight and clamp on the spool

The maslow 4.1 upgrade replaces the arm plastic to let there be bearings on the
shaft that the idler runs on to eliminate problem #2.

David Lang

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