Using small flywheel with ring gear and a starter motor as a slew gear?

[davedj1]

Anybody have any experience with slew gears?
I'm building a crane on my dump trailer and am trying to figure out how to make it rotate. I was going to use a chain and sprockets with a hydraulic motor but not sure if I can find one slow enough and powerful enough to swing 400 lbs about 10' out.
I'm not sure if a starter motor would do it either.
I want 360 degree rotation so I can load the truck also if need be.
I'm open to ideas.
The crane has a 1 15/16" shaft with a keyway in it.
Here is a pic of the crane as it sits right now.

thanks,
Dave

 

[Mendonsy]

I suspect your starter motor idea would be much too fast for what you want to do. Maybe something like an ATV winch with the cable wrapped around a large pulley might work.

 

[i7win7]

Have something similar on a dump trailer with a heavy landscape tailgate. Use lift to support gate. grab gate and walk it to side for loaded pallets. I the bearings are well greased you should be able to weld brackets on the side of the post and use a bar or pipe to turn it.

 

[metalbender]

I agree on the starter /ring gear will give you a carnival ride. A bit of work with a small winch and sprockets and chain would be slow enough. The other idea of a pipe socket to fit a handle would be ever so simple.

 

[Renze]

Starter motors run 300rpm ? You could put a clamshell bucket on it and use it as a manure spreader

 

[Smokeydog]

Don’t see the practicality for such a small crane to motor around but it could be done. Hard to beat a long lever.

Be good to also keep the manual operation also.

Large chain sprocket on hoist and small on separate shaft on base. All components available surpluscenter.com. Can drive the smaller shaft/sprocket with handle, ratchet or cordless drill.

Cranes are made and rated to lift straight up. Never side load a crane. Side loads greatly reduce structural strength.

 

[jmc]

I like the long handle except when you can't park the trailer where the vertical pivot is plumb. That might require a brake or an assistant to hold the handle while you deal with the load.

 

[Smokeydog]

When this type of crane isn’t plumb it’s a bear. One reason for the leveling jacks. Also has a jam bolt on the base that can add friction or lock the turret in place. The base has a thick bushing on top and nice thrust bearing at the bottom. Modified to take apart to carry pieces and assemble quickly. Have a hitch on side of trailer to load too. Hitches on tractor bucket, grapple, welding table, shop support post, yardbox and anvil stand.

 

[BrokenTrack]

You could use the flywheel ring gear, you would just need a way to slow down the electric motor. That should be easy enough with DC current though. You just need a motor that has enough torque at the right speed. Or you could use a starter motor with a gear reduction unit in between to get you the speed you need.

You could also go electric over hydraulic, and then use a hydraulic motor. You could get that with a used snow plow hydraulic unit.

 

[3Ts]

Worm gears would work in this application but not sure about cost. They'd provide the resistance to turning in an out of plumb situation and a significant speed reduction when using a motor. Could be manually driven as well, but would be slow.