Need for overruning clutch?

[msjanket]

Getting my bush hog ready to do some cutting. Is it absolutely necessary to have an overrunning clutch on the installation?

 

[Gunny]

I don't see which tractor you've got, but if the tractor doesn't have an internal overrun clutch, then you'd be much better off getting one of the add on styles. It's more of a control safety than anything else, if you don't have the clutch, then just pushing the clutch in won't keep you from moving forward, the inertia of the bush hog will push the tractor for quite a while.

 

[TripleR]

What Gunny said, most newer tractors have an internal overrunning clutch while some older won't. We have an old Ford NAA without an internal overrunning clutch and until we added an external one, the cutter would continue pushing the tractor forward while it spooled down, very scary.

 

[k0ua]

With most HST equipped tractors with Independent PTO, it does not matter at all as the PTO does not stop when you change directions or stop. If we knew what tractor you had, we could offer a lot more information.

 

[Mace Canute]

If you have a live or independent PTO you won't have any problem with the inertial of the bush hog pushing the tractor; it's only tractors with the PTO shaft directly connected to the tractor's transmission that can experience that problem.

 

[msjanket]

I have a Holder A50 tractor, has 56 HP, likely 50 HP at PTO.

 

[Jerry/MT]

Getting my bush hog ready to do some cutting. Is it absolutely necessary to have an overrunning clutch on the installation?

I have a tractor with an independent pto and I use a ORC with our bush hog to keep from burning out the internal clutch when I throttle back. I don't have to worry about driving the rear wheels of the tractor with he rotational inertia of the mower because I have an independent PTO but I wan't to preserve the internal pto clutch.

 

[LD1]

Gotta know what kind of pto it has. Not familiar with holder.

Does it have a 2 stage clutch?

With tractor off and in gear with pto engaged, will it free spin one direction?

 

[Texasmark]

If you have a live or independent PTO you won't have any problem with the inertial of the bush hog pushing the tractor; it's only tractors with the PTO shaft directly connected to the tractor's transmission that can experience that problem.

That's called a transmission driven PTO. The PTO is directly coupled to the output shaft of the tranny vs a separate shaft and separate clutch for LIVE and an engagement mechanism (mechanical or electrically controlled) that is totally "independent" of the tranny for INDEPENDENT PTO.

The tranny driven PTO will lock up your drive train (pressure on gears keep them engaged and resist changing....like to N) as long as the blade is turning and you can't get your tranny out of gear. You can let off the gas in your tractor and push in on the clutch but the rear wheels are still driven until the kinetic energy stored in the spinning blade has dissipated.

The after market clutch just slides over your regular 1 ⅜ PTO shaft and adds roughly 4" to the length. They are another source of sloppy fit, even when new and another source of noise and vibration, especially in turns for a drag type mower. On a 3 PT it doesn't matter all that much. Course if you had a CV joint as the first joint in your mower, right at the coupling to the clutch, the vibration on a drag would be greatly reduced.

All spoken as a graduate of Hark Knocks University getting my degree the hard way.......through 35 years of trial and error at attempting to farm with worn out equipment, no money, and nobody around that cared enough to show me how it was done rather than make a laughing stock out of me. But that's all in the past now as are they!

 

[geneP]

I have a tractor with an independent pto and I use a ORC with our bush hog to keep from burning out the internal clutch when I throttle back. I don't have to worry about driving the rear wheels of the tractor with he rotational inertia of the mower because I have an independent PTO but I wan't to preserve the internal pto clutch.

Just for discussion, I stand to be corrected. If you have an independent PTO engaged, the PTO shaft is connected directly to engine rpm either by direct mechanical hookup or through a hydraulic clutch pack. When I bring my tractor RPMs down the cutter slows, too. I bring the engine to idle before disengaging the PTO to preserve the PTO brake. I don't think there is an over running clutch in this setup. There is a PTO brake that slows the implement when the PTO is disengaged.