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Unread 17-02-2014, 10:52
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Re: Advice About Slipping / Breaking Timing Belts

Quote:
Originally Posted by Nick Lawrence View Post
Madison,

Has the intake been moved several times by hand? Does it take a significant amount of force to break the internal friction of the VP that drives the tilt? That's a huge lever arm, I would not be surprised to see much higher loads being put on that intake when it's being moved by hand, or even changing direction quickly.

9mm belts might be a little small here on their own, but one on each side oughta be enough. Is it possible that you're driving one side of the intake tilt faster than the other, and it's torsionally binding briefly?

-Nick
The collectors are quite easy to move by hand and, under power, are being moved with something like 50 or 60% of full power. One side of the mechanism is, on its own, capable of producing enough torque to lift the entire thing, so it could be possible that one of them is doing significantly more work than the other. We'll try to measure current draw on each motor while we operate it.

Quote:
Originally Posted by Chris is me View Post
In the past, we have had far less success with belt reductions, especially near the end of a gear train, than we have had with 1:1 exact center setups. We had a belt fail in a similar fashion on our 2011 drive gearbox when we tried to use it for additional reduction. Our drive belts have held up much better.

Not saying that's the source of your problems, but it certainly makes things harder. As long as you used a reasonable sized pulley and a reasonable width of belt on your drivetrain, I wouldn't worry about it.

You also want to check and make sure in a 2-belt system like you have on each side of your intake - both sides need *the exact same tension*. Any tension difference will exacerbate your problem. The fact that just one belt failed seems to indicate that this could be the problem.

If you're sure you're at the proper center and your belts are ratcheting, then the logical next step to me is to step up to 15mm belts for extra engagement.

Best of luck.
Unfortunately, we can't go to 15mm belts in this space. There's not enough room for us to bump up the thickness of one of the pulleys.

Thanks, everyone. Lessons learned -- now we'll do what we can to salvage the mechanism.
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