What has happened to my chipper

[BBBTree]

We were running the chipper for 8 hours a day for a few days, and the operator showed me that one of the disc axle sheaves had completely unbolted. As the bolts vibrated loose the disc was spinning at an angle eating the anvil with the knives.

I bolted the sheave and disc back up, and I sharpened the knives. I still need to even out the anvil with a grinder by 1/2 an inch.


Here is the problem though. I started the engine, and it was grinding or knocking. Then it back fired out of the muffler, and shut off. Now when I turn the key the starter just kind of turns turns drive shaft a little that connects to the drive belt which turns the cutter disc. I just kind of spins and kind of doesn't when I'm turning the key. The only sound it makes is the starter that seems to be spinning freely. I don't hear pistons pumping, and I don't hear any combustion of any kind.

Did I throw a rod or something?

 

[banjo]

Is your clutch seized? I can't think of why else turning the key would turn your disc.

 

[BBBTree]

I just dropped it off at the dealership to be looked at. I bet the engine is done with.

Is a clutch an easy replace job?

 

[BBBTree]

The drive shaft spins all of the time until you engage the belt with the disc. Actually there is no clutch. The drive shaft is connected to the disc by a belt, and you drop the lever to engage the belt between the drive pulley and the disc pulley.

Because the drive shaft is no longer spinning except a little here and there, I take it this is a bad sign.

 

[banjo]

I've never met a chipper without a clutch. I'm no mechanic but I understand the clutch to be a link in a system. It's the link that you control between the engine and the work parts, in this case the disc, on a truck the work part would be the wheels. If the disc is turning when you turn the key then I would assume its a seized clutch. It's like when you start a truck in gear and it lurches forward. Am I misreading the problem?

 

[BBBTree]

Yes.

Just imagine any old pickup truck engine's fan pulley with a cutter disc connected to it by a big belt. It's as simple as that. The fan pulley always spins as long as the engine is turning over. In the case of this chipper you have to drop the lever which tightens the belt between the "fan pulley" and the cutter disc pulley. That is engaging the disc.

What the problem is with the chipper engine is that the "fan pulley" no longer spins except for a very tiny bit. It won't spin in full circle. Also there is no combustion in the engine. The starter is all that is working to turn the drive shaft/"fan pulley."


haha, is that clear?

 

[SRTsteve860]

[ QUOTE ]
Yes.

In the case of this chipper you have to drop the lever which tightens the belt between the "fan pulley" and the cutter disc pulley.

[/ QUOTE ]

That lever is the proverbial clutch in this system, transferring torque from the engine to the disk by belt friction/tension. It's different from a standard system where you use plates to engage the disk.

Some smaller (usually homeowner) chippers also use centripetal clutch like that on a chainsaw, where the engine can idle independently from the disk at lower rpms.

All are "clutches"

 

[SRTsteve860]

*didnt notice this was already discussed in another thread*

apologies

 

[BBBTree]

It was the wood ruff key that had sheared off. Shwoow! I thought I was out a whole engine.

 

[tomthetreeman]

Went from a 3,000 dollar problem to a 3 dollar problem. How you feelin, BBB?

-Tom

 

[BBBTree]

Oh man, I was so ready for the bad news from the dealership...... $300 total. Haha great.

I took the chipper home, took off the anvil, and ground it flat again after the knives ate a 1/2 inch angle out of it the other day. Everything working better than ever last night, then I blew out a tire on the dump truck this morning. $300 out today, and half a day of productivity gone with it. I'm not even phased though.


And after they put that new woodruff key in, clutch is 100% smoother than it ever was.