Over Running Coupler?

[R-G]

Do these work the same as a slipclutch? Would this stop the blades from a slow spin on my bush hog when my pto is disengauged? Or do i have to remove the pto shaft everytime i lift it to move around safely? Or is there something wrong with my pto? Ive asked this before but no one answered.
Thanks.........................

 

[mobilus]

Your problem may have something to do with the design of your tractor. I was just a kid when I learned that pushing in the clutch on (if I remember the type correctly) a redbelly Ford won't stop your forward momentum when using a bush hog. I think this has something to do with a "non-live PTO" instead on an independent one like you'll find on modern tractors.

Check out this link for a good explanation: Live PTO

"With a non live PTO, the PTO is driven from the transmission gears. While using a brushhog, if you try to stop by pulling back on the clutch (or stepping on the pedal), you will stop and disengage the engine from the transmission, BUT!! the brushhog will continue driving the tractor forward (the brakes won't do much to help)!!! And if you have an obstacle in the way, that might be a problem! The only way to stop moving is to disengage the PTO, or slip the tractor out of gear. With live PTOs, this is not a problem, since it is not driven from the transmission."

Hope this helps!

 

[mobilus]

And from TractorData.com - Power Take-Off

An overrunning clutch is often needed with a transmission PTO. Without it, the driven equipment (such as mower blades) will put a force on the PTO shaft, and then the transmssion, due to inertia. The equipment will "drive" the tractor, and you will still move after using the tractor's transmission clutch. An overrunning clutch prevents this from happening by allowing the PTO shaft to freely spin in one direction. In more recent models, this is built into the tractor. In older tractors, it is an extra piece of equipment mounted on the PTO shaft.

This is probably the answer you were looking for...

 

[deerhunterf350]

What mobilus said.

An Over running Coupler allows the the PTO shaft connected to the BH to "SPIN" the coupler which is mounted on the Output Shaft coming out of the Tractor, with the momentum of the Blades, this keeps the Bushhog from OVER RUNNING the tractor when you clutch and need to stop the tractor. This keeps the Bushog from Driving the Tractor as mobilus stated.

If the PTO continues to spin slightly when it is disengaged then that sounds like the PTO Brake in the Transmission is worn , broke, or may not exist on your model .

Dan

 

[RoyJackson]

Do these work the same as a slipclutch? Would this stop the blades from a slow spin on my bush hog when my pto is disengauged? Or do i have to remove the pto shaft everytime i lift it to move around safely? Or is there something wrong with my pto? Ive asked this before but no one answered.
Thanks.........................

The other posts described an over running clutch quite well.

As far as your cutter blades rotating after the PTO is disengaged...that's normal. My 60" cutter's blades rotate for a good minute after being disengaged. They're heavy blades turning at a high blade tip speed in operation. Inertia (momentum, in this case) causes them to spin quite a while.
Removing your PTO shaft as their slowing wouldn't slow them don't any quicker. Doing this would actually increase then length of time they spin down by eliminating the drag induced in the drive train by the tractor's PTO gearing. Removing the shaft during spin down could also be quite dangerous.
If you want to slow them down faster, reduce your engine RPM down to idle before you disengage the PTO drive.

If your cutter blades are spinning even when the PTO is disengaged, as in as soon as you start the tractor, there is something very wrong. I don't know anything about those old Fords, but some of our bretheren on TBN do...specifically Soundguy. I suggest you PM him with this problem...IF the cutter is turning as soon as you start the tractor or engage a gear.
You might want to look in the Vintage Tractor forum on TBN...the answer to your question may be there

Here's something I found on an internet search:

"There is no brake system for the PTO on a SOS trans. What that means is that it is normal for a bare shaft to continually rotate when the engine is running. To hook up equipment, you need to shut the engine off.

Once equipment is attached, most implements should offer enough resistance to stop it. If the PTO continues to drive a healthy size load even with the handle in the "off" position, that usually means either the cable linkage is misadjusted, or there is mechanical problems with the clutch pack itself, such as warped plates. Check the cable adjustment first. "

This came from Re: Ford 871 SOS PTO

Good Luck and Be Safe!

 

[deerhunterf350]

R-G You asked about stopping the Blades from a Slow spin while disengaged for safe transport . Want to be clear. Lets say you go out of a morning the Tractor and BH are off nothing spinning. The PTO is disengaged , you start the Tractor , Lift the Bushhog and start driving, while driving the blades begin to slowly spin ? If that is correct then it sounds like the PTO Brake in the Transmission is worn, broke and not keeping the shaft "Locked" while disengaged. If that is the case someone with Knowledge of your Tractor will need to Chime in and make Recommendations for a Fix.


Or if you are just wanting the Blades to "Whined" down quicker after disenagaging the PTO Try the following


Experiment with how long of strip of uncut grass you need to leave, Disengage PTO and drive through uncut grass, the unpowered BH will quickly come to a stop. How quickly depends on the Size of BH, How thick your grass is , etc...

Dan

 

[R-G]

Thanks for the info, makes sense what they do. All i have to do to engauge pto is pull a handle on the dash, no "clutch" pedal, its an sos. When pto is turned off blades slow after a while but never completly stop, If tractor started, pto off, blades will start the slow spin again. If i undo the pto shaft i shut the tractor down wait till all motion is stopped.

 

[deerhunterf350]

Disregard , After reading Roys post completely I see that he answered with probably a misadjusted PTO linkage. Duh

When pto is turned off blades slow after a while but never completly stop, If tractor started, pto off, blades will start the slow spin again. If i undo the pto shaft i shut the tractor down wait till all motion is stopped.

Sounds like someone with knowledge of your Model tractor needs to chime in to see if this is normal or can be fixed.


You may ask a Moderator to Move this to the NH/FORD owning operator section , or start a thread there labeled "Ford 871 PTO Question " or something along those lines to get more response from 871 owners.



Dan

 

[greg_g]

Short version; no. An ORC does a completely different job than a slip clutch. The ORC has a bearing and rachet mechanism inside that permits the tractor PTO spline to turn the implement PTO shaft, but not vice versa: it will NOT permit the implement PTO shaft to turn the tractor's PTO spline.

//greg//

 

[R-G]

Thanks for the help, ive found a link for pto adjustment. Will try that and see what happens. Would a ORC still be a good idea to use?

 

[Soundguy]

You will get NO benefit from an ORC.. you have INDEPENDENT pto.

Ford SOS trannies have no PTO BREAK.. thus your pto can freewheel .. no way to stop it.

On ORC is not a slip clutch. A slip clutch is a torque limiter.. (akin to a shear pin ).. an ORC is a one way drive ratchet..

FYI.. this info was in my post back on 6-21 when you first posted about your tractor.. I types in a good deal of info you may find usefull on the sos equipped tractors.. here's the link.

http://www.tractorbynet.com/forums/owning-operating/102660-new-guy-first-tractor-2.html#post1165488

soundguy

 

[RoyJackson]

Thanks for the help, ive found a link for pto adjustment. Will try that and see what happens. Would a ORC still be a good idea to use?

Probably, but try the vintage tractor forum or Yesterdaystractors for a more authoritative answer.

I see Soundguy provided an answer. Well, he's our resident Guru on old iron...

 

[greg_g]

Thanks for the help, ive found a link for pto adjustment. Will try that and see what happens. Would a ORC still be a good idea to use?

According to TractorData.com - Ford 871, the 871 has a live PTO. That makes ORC is a waste of money. If you have some kind of 871 variant without a two stage clultch, an ORC then becomes inexpensive driveline protection.

//greg//

 

[Soundguy]

An 871 has fords SOS (automatic ) tranny and thus has fully independent pto.

The ford 2-stage clutch models were identified with a '6' as the middle digit of the hundred series.. IE *6*...and the SOS were *7* or *8* of the pto equipped models.. etc..

Soundguy

 

[canoetrpr]

While on the topic of over running clutches... my Kubota L3400HST has in internal over running clutch. Throttling down when the PTO is engaged or depressing the clutch causes the ORC to rachet as expected, until the PTO lever is turned to the OFF position.

Newer models of the L3400HST don't have an over running clutch an more.

I can't quite understand why an ORC would be required at all on this tractor since it is HST.

I can part understand it in the throttling down scenario...maybe the implement would still 'drive' the transmission causing unnecessary wear, but surely it would move the tractor forward??..I can't figure out why the manual suggests depressing the clutch before putting the PTO in the off position. One would think that I should just be moving the PTO to the off position without throttling down or without clutching....

Some have managed to get their PTO changed to use the newer stuff which does not have an internal ORC (even stranger why the new design does not require it when the old one did). I won't be doing this. So I was wondering if any harm can come at all if I purchase an external ORC for piece of mind.

I would think that the external ORC should cause the internal ORC never to rachet - throttling down or when the clutch is depressed ... and this would be cheap insurance.

As you can tell, I'm pretty confused. Anyone care to comment?

 

[Soundguy]

My guess is they use the internal ORC on that hst unit to save the pto break ( if equipped )?

That's what I'd do if I built them anyway..

Soundguy