How do you find the center to center distance with a twisted belt. We want to use one for the feeder rollers to our shooter mechansim, but we aren’t sure what size belt to use.
I would imagine that if you use cad to calculate the figure 8 shape you could get the loop length of the belt that would be quite close.
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I assume that you are talking about double sided
I used a feature script from onshape. You are choosing the surfaces the belt will go through and the surfaces that they will be inverted
We used it last year in our last years intake.
Hope this will help you.
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If you are asking about twisting such that it reverses direction, I spoke to a team that had this on their robot, and they said it was a manual process of measuring a mockup. I’m not sure if someone else has a better way.
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We always just run a piece of the belt to match the path.
Take a longer piece and “Install the Belt”
Mark where the uncut length meets the end
Lay it flat and measure the length from end to the mark
Cut it so your total length equals your path length minus 5-10% depending on how tight you need it.
Remember, you can always cut it and shorten it if it is too loose.
Are you saying that you make custom timing belts? If so how do you attach it again after it’s cut?
I got the vibe they wanted to use a timing belt for this…
Personally, I’d strongly consider a flat belt or polycord as it can act as a clutch too.
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Ohhhhhh, I was talking about poly belt. If you are doing timing belt you are just going to have to guess and check?
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We had tried to fuse polycord a week or two ago and it wasn’t working well, but I think we will try again now.
We had thought timing belts may be easier, but I also realize that we want the rollers to be a certain c-c for the right amount of compression. If the ones we have in house happen to work we will do that otherwise we will try polycord again.
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https://youtu.be/fYKsIe-yMrA?si=sBjPaXL4VhdXjxxe This is how 1678 welds belts.
Draw out tangent lines of the belt path and offset by the width to figure out the belt length. It will be slightly lower, so add the thickness of the belt to your final perimeter a decent approximation. The best practice would likely be adding a cam tensioner/bolt with a spacer to tension.