Design of flat belt conveyor

You might start at Goodyear's technical help site
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Reply to
Fred R
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This URL looks like a good place to start, an engineering view of crown.
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I found it with a google search of "pulley crown", the 5th hit, so not hard to find.
Richard
SBAER wrote:
Reply to
Richard Ferguson
I am an engineer, I do machine design on a contract basis mostly
automation equipment. I have to design a flat belt conveyor (something
the customer normally just purchases) about 10" wide and 24" long.
My question concerns the crown on the pulleys. Does the tail pulley
have to be crowned as well as the head pulley? I prefer to approximate
the crown by turning a slight angle on each end of the pulley so that
the machining can be done on a simple lathe. Does anybody have a
suggestion as to the angle and length of this chamfer?
My four year engineering education did not cover this (or anything else
that might be of use to a automation designer) and none of my handbooks
have do either.
Any help would be appreciated.
stan
Reply to
SBAER
Here's some info from Habasit, you could probably find more on Shingle and Siegling's websites...
You can purchase crowned conveyor pulleys with QD hubs from Van Gorp. Van Gorp used to be part of Browning and Emerson Electric-that doesn't appear to be the case any more.
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If the 24 inch length is not a misprint, one crowned pulley should be adequate.
Ned Simmons
Reply to
Ned Simmons
SBAER wrote in news:h8ydnQ2GgYKOzWXcRVn- snipped-for-privacy@rogers.com:
Cross posted to AMC where Koz may be able to help you out. He may even be able to get you the exact conveyor you need, without you having to design it.
Reply to
Anthony
Stan, where are you located? Ive got a Shitload of stuff for conveyor systems that I need someone to haul off.
Gunner
"Gunner, you are the same ridiculous liberal f--k you ever where." Scipio
Reply to
Gunner
sure does
I prefer to approximate
I usually used 1/2 a degree. You get better results though with a tracking strip welded onto the centre of the belt and a groove in the pulleys. Try the belt supplier for details. Tom
Reply to
Tom Miller
> > > >>I am an engineer, I do machine design on a contract basis mostly >>automation equipment. I have to design a flat belt conveyor (something >>the customer normally just purchases) about 10" wide and 24" long. >>My question concerns the crown on the pulleys. Does the tail pulley >>have to be crowned as well as the head pulley? I prefer to approximate >>the crown by turning a slight angle on each end of the pulley so that >>the machining can be done on a simple lathe. Does anybody have a >>suggestion as to the angle and length of this chamfer? >>My four year engineering education did not cover this (or anything else >>that might be of use to a automation designer) and none of my handbooks >>have do either. >> >>Any help would be appreciated. >> >>stan > > > Stan, where are you located? Ive got a Shitload of stuff for conveyor > systems that I need someone to haul off. > > Gunner > > "Gunner, you are the same ridiculous liberal f--k you ever where." > Scipio
Reply to
SBAER
Sigh...nope...not a quick one.
ROAD TRIP!!!!!!!!!!!!!
Gunner
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Reply to
Gunner
Although there are several factors involved, the actual answer to the amount of crows is"as little as possible". Yea, that doesn't answer the question at all. Assuming the belt is nearly perfect and mostly non-elastic, crown would be approximately 1/5 of the belt thickness relative to the radius of the pulley. In addition to providing some minimal tracking, a crown is really there because most of the thickness errors and wavyness in the belt strip material occur in the outer 20% of each edge. By relieving the pressure against the pulley on these outer edges (smaller pulley diameter under the outer edges), errors in the strip at this point have a reduced effect on causing tracking errors.
Regarding doing the crown via a taper, that's called a "narrow bodied roll". Typically, 60% flat in the center, 20% tapered at each edge by reducing the radius 1/5 of the belt thickness, with some flat left over on each end so that if the belt wanders, it doesn't wander off the edge of the pulley.
Reality is, however, that belting strips tend to be elastic and require slightly greater crown than the 1/5 of the belt thickness mentioned. This becomes a subjective matter depending on so many factors that it can become a guess. It tends to be relative to the belt thickness and width. Crown should usually never be more than the thickness of the belt. However, this rule falls into the dumpster for really wide belts. Same goes out the window the other direction for small diameter pulleys: crowning the thickness of the belt may make it act weird if the pulley is a 1" diameter nosebar.
As to crowning the tail pulley, In theory you should. On most conveyors the only place to provide any tracking adjustment is at the tail and having a little crown here can improve the system so that it isn't so "touchy" to adjustment. The goal is to get the belting to come of the tail heading the right direction (square to the frame) and enter the head pulley square to the frame. People tend to neglect the return sides of the belting when designing conveyors (belt goes on a roller coaster rode) so the tail pully crown tends to be needed to compensate for errors induced by the return side.
Tracking is NOT accomplished by tensioning the belt. The only tension on the belt should be enough pressure on the drive pulley so that Friction factor of the pulley x Pressure overcomes Friction factor x Pressure of the rest of the conveyor. Anything more than that just wears things out. To track an unruly belt, Think in terms of RELIEVING tension. That is, don't tighten one side to get it to track, loosen the other side. Once it starts appearing to track OK, then start tightening BOTH sides evenly to make sure there is enough pressure on the drive to overcome the friction on the rest of the conveyor. When doing this, you may have to make some slight adjustments in tracking angle of the pulley...kind of a process of apply a little more tension to both, adjust tracking via reducing tension on one side...apply a little more tension to both process.
Even when doing all the right tracking adjustments, they sometimes seem to have a mind of their own. Assuming that everything is square in 3 dimensions and the belt is good quality, sometimes you just have to consult the voodoo gods and do whatever works.
Koz
Reply to
Koz
The end user can probably get away with a stopgap solution like this, but the fabricator can't. That one in a million chance that some idiot gets caught in a "tape" that unravelled is too big a risk. All it takes is for some maintenance guy to reverse a pulley and any tape-like substance (glued well or not) will unwind over time. There are cases of glued on urethane sheets that were pre-crowned while flat that have worked though.
When you can get sued (and lose) because someone else was stupid/ removed guards/ ignored warning label with idiot symbols, etc., it's best not to vary from industry standards of construction.
Koz
Reply to
Koz
Try this site
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Reply to
Peter

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