Pulling very large gears

I am eyeing a job that would involve pulling large gears off their
shafts. Gears are 3ft in diameter and some may be even 4ft.
This being the United States of America, I am sure that commercial
solutions have been developed for that kind of thing. I wonder what
sort of places should I call to rent some big gear pullers?
i
Reply to
Ignoramus7394
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Wow!
I've not worked that size range. But as gears and pulleys get large, pulling them by spanning their entire diameter becomes problematic.
Are there any threaded holes near the shaft boss? Or access between spokes or 'lightening holes' where one might use a smaller puller? I'd be afraid of bending the gear by pulling on the periphery.
I'd look for something like this:
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and try to get hold of the gear as close to the shaft boss as possible.
Reply to
Paul Hovnanian P.E.
You might tell us a bit more. If you are trying to remove the gears so they can be used again, that is one thing. If you are going to sell them as scrap metal , that is another.
One option is to cut the shafts with a oxyacet torch and never pull the gears at all.
Dan
Reply to
dcaster
I cannot cut the shafts. It involves moving a machine for a customer. He wants some gears and does not want other gears, but he wants the shafts.
i
Reply to
Ignoramus7394
Try Ahern. 50 ton porta power should pry them off without damage.
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Best Regards Tom.
Reply to
Howard Beal
I have no idea of where to rent gear pullers of that size. There might be such a place, but I kind of doubt it. I expect you are going to have to ju ry rig something using some I beams, heavy chain , and a hydraulic jack. P enetrating oil and warming up the gears will help. Liquid nitrogen on the shafts will also help. Your local welding supply can help with the LN.
Dan
Reply to
dcaster
Probably not that much, but you never know. My biggest concern would be handling the gears as they come off. A forklift positioned just right might help, but if the gear turns it could still fall catastrophically.

Reply to
Bob La Londe
Good point.
I would definitely suspend the gear on a strap before pulling.
Reply to
Ignoramus7394
Depending on the gear ( spokes or solid ) the rigging is fairley simple with igy's big forklift. The big problem is gonna be overcoming the sticktion between the shaft and the gear bore.
Best Regards Tom.
Reply to
Howard Beal
Right. Those gears do not need a big forklift. A 5,000 lbs forklift would be just fine to suspend the gear on a choked strap.
i
Reply to
Ignoramus7394
Years ago I had to pull some large diameter flat belt pulleys off of their shafts and at first it was not obvious what was holding the pulleys on. It turned out that they were held in place with tapered keys. I don't remember if it was the keyseats in the shafts or the pulleys were tapered to match the key. Anyway, the keys weren't just a straight taper, at the big end there was a step. After the key was installed you could pound on or pry against this step to remove the key as it was taller than the rest of the key. I think this type of key is called a "Gib Head" key. So if the big gears you are going to pull don't have any obvious clamping feature it may be they have the tapered keys. Eric
Reply to
etpm
no answer to this, but did you make it to the Wisco openhouse last week?
There was quite a bit of welding and cutting equipment to play with.
Reply to
Cydrome Leader
I did not, unfortunately...
i
Reply to
Ignoramus9441
What's holding the gears on?
Reply to
Tom Gardner
How are they retained on the shaft? Press fit, clamp collar, set screws, gib key? For big gears I usually use a set of wedges. That or machinist jacks.
Reply to
Steve W.
As others have mentioned, how are the gears attached to the shaft? There is a good chance that they are not simply pressed on, there instead being some kind of taper lock or hydraulically actuated mechanism that causes the gear bore to expand. These methods are made by specialist companies, who typically put their logo and model number somewhere visible even in the assembled gear on shaft.
Joe Gwinn
Reply to
Joe Gwinn

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