Timber crane/backhoe slew ring

[Stimw]

Thanks for the replies. So its not looking good for the flywheel idea - I can see that. I will use the hub from a 12t axle for the bearing, I think this will be plenty strong enough. I had also thought of using a triplex roller chain and 2 sprockets. I was worried about too much play if I did this, but maybe it would be OK after the initial stretch. I have the chain and one sprocket already, so I would only have to buy the large sprocket - this would fit into the low cost/no cost budget idea for this build ! Stimw ; did your boom truck do OK with the chain and sprocket or were you forever fiddling with it ? It looks like the Wallenstein cranes use this type of system

The boom was on a Ford with a CAT engine and had a 20' bed set up to haul concrete block.
I could haul 10 cubes (90 8" block each cube) and had block forks.
The boom had-
Boom up/down
Rotate 360* R/L
Trolley in/out
Cable up/down
Separate control for outriggers
When I would rotate with a full cube of block I had about 4000 lbs that I was moving.
To rotate I had to bump the switch several times to get it started, then let off several times to stop due to the pendulum effect.
I LEARNED THAT THE FIRST TIME I RAN IT!!!!

 

[kenord]

Some old backhoes used a heavy roller chain connected in the center to the mast, then a hydraulic cyl on each end of the chain to pull it around for the swing. Im not sure you would need a sprocket. but would need something to hold it away from the mast. Hope this helps give you some ideas.
Have fun, stay safe,
Rich

 

[CADplans]

Some old backhoes used a heavy roller chain connected in the center to the mast, then a hydraulic cyl on each end of the chain to pull it around for the swing.

WOOT!! I really like that concept,,,

as for the pivot,, I learned a LONG time ago that a bearing needs velocity to keep lube on the rollers/balls,, etc,,
fretting will destroy the surface of a slow operating bearing,,

A bushing is used for slow speed,,, IMHO,,,

 

[Egon]

Any chance a truck differential could be rigged up and connect the drive shaft to a properly geared drive?