Overrun clutch for flail mower ?

[Paul Allwood]

For those who know more about this stuff than me (most of you), do I need a PTO overrun clutch when using a flail mower ?

This is for the mower I'm building that will run from the mid PTO that doesn't include overrun protection. On my tractor it's only on the rear PTO.

 

[Runs With Scissors]

I have seen a few “semi- different” definitions of an "over-run clutch"

(and a few different names…i.e. Sprag and One-way clutch, to name a couple)

What are you trying to prevent?

 

[SDT]

For those who know more about this stuff than me (most of you), do I need a PTO overrun clutch when using a flail mower ?

This is for the mower I'm building that will run from the mid PTO that doesn't include overrun protection. On my tractor it's only on the rear PTO.

Hard to say considering you are building your flail mower. No way to know what inertial effect your mower may have.

 

[NCL4701]

You need over run protection in the drive system somewhere. If not, the momentum of the mower will push the tractor when you’re stopping or slowing down. How much mower generated inertial push you’d have is pretty hard to predict, but it would almost certainly fall somewhere between very irritating and quite dangerous. Just an opinion.

Edit: In deference to those more familiar with your specific machine, I withdraw the above.

 

[Bee-Positive]

I believe the B7200 Mid PTO system is independent (live) of the HST.
Live PTO:
The PTO spins, regardless of what you do with the transmission and transmission clutch. The PTO is connected to the engine directly separate from everything else.
Non-Live PTO:
The PTO is driven off the output shaft (counter shaft) of the transmission, and not the engine. Push in the clutch, and the PTO stops spinning.
You need to be in neutral to separate the PTO shaft from the driveshaft. Hence the nasty habit of bush hogs shoving tractors around by their rotational inertia, and the need for an overrunning clutch.

A slip clutch/shear pin and an ORC do not serve the same purpose.

Having a slip clutch instead of shear bolts would be something to look into for times you hit unseen immovable objects (you know you will).

All that said I would think having an ORC would be a good safety feature if your flail doesn’t have a gearbox with a freewheel clutch.

 

[Russell King]

Doesn’t the mid PTO of the tractor already have an over run clutch built in?

 

[North Idaho Wolfman]

You need over run protection in the drive system somewhere. If not, the momentum of the mower will push the tractor when you’re stopping or slowing down. How much mower generated inertial push you’d have is pretty hard to predict, but it would almost certainly fall somewhere between very irritating and quite dangerous. Just an opinion.

Not on an HST tractor.

 

[North Idaho Wolfman]

For those who know more about this stuff than me (most of you), do I need a PTO overrun clutch when using a flail mower ?

This is for the mower I'm building that will run from the mid PTO that doesn't include overrun protection. On my tractor it's only on the rear PTO.

No you should not need an Overrun clutch on the mid PTO drive.

 

[Paul Allwood]

Doesn’t the mid PTO of the tractor already have an over run clutch built in?

No - only on the rear PTO on mine.

 

[Bee-Positive]

After reading North Idaho Wolfman comment about an ORC @ 2,500 RPM being dangerous on your other post I have to bow to his wisdom and retract my endorsement of adding such a thing.

Which leads me to a question that may have already been answered since I am lazy and didn't reread all the previous posts - are you sure operating a flail mower at such high RPM's is a good thing? I imagine the it could be geared down to a reasonable speed but the PTO to the gear box stress would have to be something to consider. Or maybe there are flails that operate at those PRM's and I am just not aware of them.

 

[Paul Allwood]

After reading North Idaho Wolfman comment about an ORC @ 2,500 RPM being dangerous on your other post I have to bow to his wisdom and retract my endorsement of adding such a thing.

Which leads me to a question that may have already been answered since I am lazy and didn't reread all the previous posts - are you sure operating a flail mower at such high RPM's is a good thing? I imagine the it could be geared down to a reasonable speed but the PTO to the gear box stress would have to be something to consider. Or maybe there are flails that operate at those PRM's and I am just not aware of them.

All good. If it's ok, I'll answer your rpm query over in the fabrication thread....

Front mount flail mower from mid PTO

I'm still playing with ideas for a front driveshaft, but one that provides greater movement than can be achieved with just the mid-PTO shaft and the female spline sliding over it. For now I'm going to just make a 3-point mounted finish mower. Might try something different like a front mounted...

www.orangetractortalks.com

 

[Russell King]

All good. If it's ok, I'll answer your rpm query over in the fabrication thread....don't know how to create a link to it ?

Here is the link (and instructions are below the link)

Front mount flail mower from mid PTO

I'm still playing with ideas for a front driveshaft, but one that provides greater movement than can be achieved with just the mid-PTO shaft and the female spline sliding over it. For now I'm going to just make a 3-point mounted finish mower. Might try something different like a front mounted...

www.orangetractortalks.com

Go to the thread you want to link to and “copy” the address
Then go to the thread you want to link from and paste that address into a new post (or add it on an edit to an existing post).

The address should look something like this
“https://www.orangetractortalks.com/forums/threads/front-mount-flail-mower-from-mid-pto.79725/ “

 

[Paul Allwood]

Here is the link (and instructions are below the link)

Front mount flail mower from mid PTO

I'm still playing with ideas for a front driveshaft, but one that provides greater movement than can be achieved with just the mid-PTO shaft and the female spline sliding over it. For now I'm going to just make a 3-point mounted finish mower. Might try something different like a front mounted...

www.orangetractortalks.com

Go to the thread you want to link to and “copy” the address
Then go to the thread you want to link from and paste that address into a new post (or add it on an edit to an existing post).

The address should look something like this
“https://www.orangetractortalks.com/forums/threads/front-mount-flail-mower-from-mid-pto.79725/ “

Thanks Russell