Re: How to Couple Belt Cleats to Pulleys

ptc-5041969 · ‎Mar 16, 2015

Hi all.

I am working with Creo 3.0 and need to perform a motion analysis of a handoff between cleats on two conveyors. The conveyors will physically be chains but for my analysis, either a chain or belt will suffice. I would like each of the two conveyors to have three pulleys, one fixed location driver, one fixed location driven and one floating location driven (a tensioner). Attached to each of the belt/chains will be a pattern of cleats at a predetermined distance, equally spaced relative to the belt/chain length. The two conveyors may or may not be mechanically connected via a third belt chain.

I have the pulleys placed in an assembly and a belt feature of specified length created. By dragging the driver pulley, the other two move via the belt feature as expected. I have created a cleat which I have restrained to the belt feature curve via a planar constraint and two point (cleat) to curve (belt curve) slot constraints. I can drag the cleat around the belt curve manually as expected.

What I would like know is how to mechanically couple the cleat movement to the pulleys. I would like to drag the pulley and have the cleat move in sync. Essentially I am looking for a mechanically functional belt feature/assembly. How can I do this or is it even possible?

Thanks in advance for your help.

Frank Root

UCT

Chandler, AZ

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TomD.inPDX · ‎Mar 16, 2015

That's a tough one since the belt feature is merely a perimeter controlled curve.

I am going to suggest you need to make the belt a linked chain. That way you can tie your cleat to a link and it will follow with ease. The only thing the links won't do be "bend" around the corner. It will cog due tot he cord length of each link. So the catch 22 is that you make a lot of link to simulate the bending around the corners, or large links to keep the model simpler and dynamic.

I just got done doing this with a cable track. I had to disconnect it in the higher level assembly because, even with only 22 links, my drag-component functionality pretty much sucking every CPU cycle into the dirt.

ptc-5041969 · ‎Mar 17, 2015

Yeah, agreed.

I have been working on this for a few days now, seen just about every tutorial and YouTube video on the subject and have yet to come up with a suitable technique. I even modeled the entire chain, some 70 links, simple models, but it is essentially unusable. It just can't handle to calculations required. SolidWorks appears to offer no good solution either.

There needs to be a way to couple the belt feature or representative chain to a pulley/sprocket such that I can space out cleats every 15 inches or so and drive them with the pulley/sprocket by dragging. This would be huge in motion analysis of conveyor handoffs.

Anybody else know of a suitable technique?

TomD.inPDX · ‎Mar 17, 2015

Actually there is but it is still interpretive (fooling the system).

There is such a thing as a slot motor, but it requires an optional mechanism extension.

The idea is that you assign a slot motor to your cleat and it can maintain a constant momentum along a curve.

I have come close to this by pulling a part along a curve with a servo motor but the velocity has to be adjusted for along the path.

ptc-5041969 · ‎Mar 17, 2015

Sounds like a slot motor would do the trick. I guess I have to ask PTC why the slot motor is not part of the Mechanism suite of motors... Thanks for you help...