Brush Shredder, for PTO

[andyfletcher]

Has anyone built a brush shredder for PTO (35HP)?

I'm thinking to build one that can chew up 4in saplings, but not one that has a self feed, which would be dangerous for me to build. I have the basic idea in my mind and I'll work on a diagram to present here, but basicly it goes like this.

A 15in X 5/8in thick steel plate that has 2, 4inchX2in slots in it that I'll fit 2 hardened blades set at 30degress. A 1 1/4in hole is drilled in the center to receive the shaft

I'm going to gear the 540 RPM up to roughly 1000 RPM.
with either a 2 sprocket motorcycle chain or gears. I figure it will cost me 3 or 4 HP at the machine which I can spare.

I may flywheel the shaft using a baler flywheel or something lighter and use a PTO w/overrun adaptor. It will lighten shock whenever a log is jambed in. (But flywheels scare me.)

I'm going to shear bolt the drive shaft that has the larger gear at PTO.

The shreddeer housing made of 3/16 plate, with throat that restricts feed to 4inches.

So this setup is a chew type chipper rather than a chopper.

Thanks for the help.

Fletch

 

[Soundguy]

A couple Issues. I'd expect the motor cycle chain and sprocked set to become a memory the first time a 2" woody limb hit it. And that ORC on the pto shaft will do absolutely -0- to cushion the load. The only thing it will do is let the chipper freewheel, if it should for some reason ever be turning faster than your tractor pto... like.. if you turn your tractor off.. or throttle down... that's it.... no cushion. an ORC is 100% direct drive via ratcheting dogs in the 'driven' direction... no give...

A slip clutch is a torque limiting device made to slip when overloaded.. etc.

If you are loading enough to get your slip clutch to let go on the 35-30 hp pto.. then again.. I'd use about 6 or 7 paralleled motorcycle chains /forums/images/graemlins/grin.gif

Soundguy

 

[andyfletcher]

Soundguy:

Thanks for the tip.

I guess the gearing would be the better choice.

I figured that after seeing so many choppers doing wheelies on popped clutches with 200 lb bruisers driving them that the chain can handle the shock. /forums/images/graemlins/grin.gif

Good point on the ORC, I guess a clutch would be better. The ORC goes for 70$ +- in these parts, does PTO clutch run the same price?

Do you see any problem with chip ejection and buildup with green wood? Should I just make sure I have enough free space in the housing and let gravity handle it, or do I need a turning paddle type arrangement behind the plate that cleans the chip area?

Andy

 

[Soundguy]

To be honest about chip port.. I couldn't say. Perhaps you can download a pdf format of a different cheipper or two.. and see how they handled it.

As for the motorcycle chain and shock loads.. keep in mind there is still a clutch in the system, slipping a bit.. and the load is a rolling load.. such that the motor and chain can rotate around the axle.. it's not like shoving a fence post into the end an having a blade cut a slice off or stall... etc..

A tractor pto/engine is running at full power when that wood goes down that chute. A motorcycle engine.. if running wide open.. I'd expect a lot of clutch slipping be the operator in order not to kill himself.. or if the clutch did pop at max rpm.. I'd expect there to need to be mechanical repairs to either the bike or the rider afterword.. IMHO.

Soundguy

 

[Deerlope]

What ever you build just make sure that the chipper flywheel is powered by 2 "V" belts. Otherwise you and your invention will be history. Belts will take that initial shock.