Chipper Disengaging chipper

   / Disengaging chipper #1  

avorancher

Silver Member
Joined
Jul 29, 2003
Messages
215
Location
Deluz, CA
Tractor
Kubota B7800, RTV900
I run a Jimna 6 chipper on a B7800 and love it (both). But I do have a question about engaging and disengaging the PTO when the chipper is hooked up.

I usually engage the chipper at a low RPM, then speed up the engine until it is full PTO speed. This seems like a better technique than engaging it at full engine speed by "slipping" the clutch.

Lately, I've been slowing down the engine speed before disengaging the clutch. This seems to put some strain on the engine and drivetrain and I'm wondering if this technique is hurting anything. My old method of pushing in the clutch and disengaging at full PTO speed kept the chipper spinning for a long time before stopping.
 
   / Disengaging chipper #2  
I don't have a chipper yet, but a rotary cutter might be a close equivalent...

I engage the PTO at low RPM and I disengage at low RPM. I will let the engine run at a lower (1200-1400) RPM for 30 seconds or so before disengaging. Can't say I've noticed any strain.
 
   / Disengaging chipper
  • Thread Starter
#3  
The flywheel of the chipper is so heavy that the engine braking is significant and I can feel the torque and hear a whining sound as it slows.

It is probably no more stress on the drivetrain than just backing off the throttle while going downhill and having the whole tractor momentum to slow.

Maybe I can just ease the throttle down instead of backing off all at once.
 
   / Disengaging chipper #4  
</font><font color="blue" class="small">( I usually engage the chipper at a low RPM, then speed up the engine until it is full PTO speed. This seems like a better technique than engaging it at full engine speed by "slipping" the clutch. )</font>
I have the same chipper on a B2910 and that's how I do it.

</font><font color="blue" class="small">( Lately, I've been slowing down the engine speed before disengaging the clutch. This seems to put some strain on the engine and drivetrain and I'm wondering if this technique is hurting anything. )</font>
That's also how I have been doing it ... and you are right - it does put some inertia behind the engine slowing. Normally whenever I've been using my backhoe I just reach over to the rear PTO lever and flip it out of gear (no clutch), although I've usually slowed the engine at that point. The PTO pump doesn't put much load on the tractor. It seems to me that disenaging the PTO is pretty smooth at most speeds, even without using the clutch.
 
   / Disengaging chipper #5  
Personally I don't like that kind of stored energy driven back into my drivetrain from the multi hundred pound flywheel. All of my tractors have overriding clutches build in (or added externally) to prevent the kind of damage driving the PTO externally can cause. Even with that protection, one of the other members on this board borrowed my Ford 2120 (which has an internal overriding clutch) and managed to shatter the clutch with a 6 foot bush hog. I always slow down the PTO speed before disengaging the PTO, but I still feel you need an overriding clutch..

Andy

PS- see my post on the Bush Hog Suddently Stopped Mowing to see what happen to my Bush Hog when I was forced to use it on a larger tractor than it was designed to be used on. Lots of forces there.
 
 
 
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