Decoiler Design

I have seen decoilers driven with hydraulic motors requiring no brakes and direct electric driven decoilers which, as I recall, had a brake. If I understand your intentions, you intend to pull the sheet off the roll without any power from the decoiler, is that correct? I have 2 comments about the picture, based on my limited experience with decoiling. One, if that brake is on the final drive shaft, it looks too small for the size coils you gave. Second, if this is for a machine that is going to see prolonged duty, maintenance will be a problem since the whole shaft will have to replaced when it wears. A more easily replaced drum and a brake system with more area should be used (or a hydraulic motor system).

Thank you Bigg

I agree it does look very small for the intended task. The decoiler has been in daily use for 20 years (hence the B&W photo from the instruction manaul). The coils are 750kg and I'm told by the owner it still works fine. The shaft has wear, but nothing catastropic.

This decoiler is on a roll former and is not powered.

Tony

Decoilers are usually turning at a very slow speed so I am not surprised that the system pictured worked so well for the last 20 years. Most of the decoilers in my experience are hydraulic but I don't see why the system pictured wouldn't work. It is acting more as a run damper much like a spring loaded spool carrier in a mig welder which prevents run on once the wire spool stops spinning. If you have a limit switch controlled stop on the guillotine to stop and start the powered rollers I don't see why it wouldn"t do the job. As for the jaws to grip the coil, I would probably just use 2. One would be fixed and the other retractable. When loading the spool the retractable on would be wound in (hydraulically, pneumatically or manually, up to you) the spool loaded and then wound out again to put some tension on the spool. The jaws would be semicircle in shape with enough room taken out of the middle for the fork tine and to allow for the ovaling of the spool when hanging unsupported from the fork tine. Once the other jaw is wound out the 2 semicircle would provide support around the majority of the spool maintaining roundness of the spool and putting even tension on the spool so as it got smaller and smaller it would still retain its shape without the support or hundreds of layers.

I think you are trying to keep cost down by doing this yourself, but I have found that these guys are pretty reasonably priced. I would compare the purchase price of what you need to the home built cost, including your time.

www.rapidair.com

At least the web site can give you some ideas on how to build your own.

Dear Tonymech

See image ... this is how we make narrow coil unreelers.

http://s5.postimg.org/hp9b0tmbb/01030805_image_solid.jpg

Most of the weight sits on the bottom two rollers and the higher two stop the coil from jumping of the bottom two rollers.

The bottom two rollers can be chain driven ... some times we drive them sometimes we do not.

Batt

Thank you Batt

That coil is very narrow and I appreciate it must be supported at the sides and this would probably be OK for 200. We made a one with 2 rollers and no side support and the coil constantly ran sideways needing someone with a rubber mallet to correct it. A 1200 wide coil maybe OK, but 200 forget it!!

Tony

Dear Tonymech

Did you copy the image link ... you will see it has side rollers.

Batt

Yes, thank you, I looked at the JPEG and saw the side rollers. The other problem with heavy colourbond coils is marking the surface, although the one in the photo didn't seem to worry them.

Tony