PTO Drive Outer Housing Spinning Question

[wstr75]

I replaced the safety tube today that covers the drive shaft on my Howse rotary mower. The previous safety tube had fatigued and broken away at the tractor connection end and exposed the u-joint.

Question: Does the safety tube rotate when the implement is engaged? I secured the little chain that came with the tube but it immediately was jerked apart when the pto was engaged. My assumption is the tube rotates when the pto is engaged but that it would stop rotating and slip if something where to get entangled with the tube.

I checked the tube and it readily slipped when held (this is with the motor not running).

 

[Willl]

I've always thought the chain was to secure it from spinning ?

Non the less, I personally wouldn't have replaced the cover. Always thought it wasn't a good idea to get close to a bare shaft while rapidly spinning.

 

[aczlan]

I would shoot some grease into the "bearings" at the ends of the cover. The chains should be able to hold the cover still when the PTO is on.

Aaron Z

 

[Gary Fowler]

I just check mine when I hook up to make sure they will slip but I never hook the chain, in fact I removed the safety chain when I got the bush hog. I think that is more dangerous than not having a guard. That flimsy little chain and hook could come unfastened and slap you a few times doing some major damage if it came undone or become a projectile. There is enough friction to really spin that chain if it comes loose. As long as it stops spinning if something gets into it, that is all the safety you need. Best safety is to stay away from spinning shafts even if they have safety guards on them

 

[wstr75]

I truly appreciate these replies. It makes me feel better and confirms my assumptions about the safety tube covering over the PTO drive. As a boy in the 1960s I drove tractors without PTO covers and knew to be careful at all times. As a fifty-something man who has recently gotten back into tractors, I was questioning my reasoning. Thanks for helping me understand.
Bill in NC

 

[3035user]

If they were supposed to turn why would they put them on? I always hook my chain up.

 

[Skyco]

Both PTO driveshafts I own ripped the chain out almost immediately...there needs to be a better system for them to remain stationary while the shaft spins inside.

 

[zzvyb6]

The outer shield should not be rotating. Its kept stationary so that if a pant leg, shirt sleeve, glove, baler tie string, tarp cover, corn stalk, hat, boot or sock touches it, it won't be grabbed and pulled into the shaft and wound up. Now imagine a jacket sleeve getting caught while your arm is in the it.

A few years ago, a fellow was mowing the side of a 4 lane highway just 2 miles north of here. People stopped only when the tractor ran out of fuel. The kid operating it had gotten a pant leg caught, probably when he jumped the pto shaft to get to the other side of the mower. He probably died instantly, but was spinning around the shaft with body parts flying off for 2 hours. And, nobody realized it had happened. I knew him as Rick....

 

[wstr75]

Well, if the tube is meant to be stationary, it is going to need something more substantial than the weak chain that came with the tube. Perhaps a stainless cable. Maybe secure it at the gearbox end and also at the tractor PTO end.

Anybody here rig up something more substantial to keep the safety tube from spinning?

Bill in NC

 

[JimRB]

Not that I have thousands of hours of bush hogging experience but I have used bush hogs with pto shafts covers for 15 years. I have never had a chain fail. I have had some cables fail. Really the chains are not taking any huge amount of torque. That little plastic attachment point would fail before a chain would fail. If that cover has that much friction then that needs to be looked at. Of course if you choose to sit or stand on the cover while the shaft is spinning you might experience disaster.

 

[Skyco]

That little plastic attachment point would fail before a chain would fail.

Thats what happened to mine, ripped the plastic ear right off both of them when they bound a little bit for some reason.

 

[Cidertom]

I will second the comments that it shouldn't rip chain or tear the plastic. The whole idea is that there is NO spinning item you can brush against. Most I have seen issues with are lack of lube or just dirty. If it doesn't turn free, it has a problem.

After 30 years as an EMT in rural areas: The old "my grandpappys tractor didn't have it, why should mine" gets pretty thin while I have to un wrap the injured/dead from the shaft. Fewer people are being hurt today than in the past, despite more "tractors".

Yes there are issues that have to be dealt with. The PTO shield on my JD interfered with the the pto shields on the drive lines. In the end I removed the JD shield, as the area was protected by the bell on the pto shafts. But: I have properly operating shields on all pto shafts so I still have protection from the accidental contact.

No one goes out to get hurt/killed with their tractor, it is that split second of inattention or careless leaning that causes most of the grief.

 

[wstr75]

I put a chain on both ends of the PTO cover with both chains at right angles to the shaft. This solved the spinning problem.

However, did not bush hog for long today because the mower pushed up against a rock and bent the outer housing under and into the blades. This is the second time the outer housing bent under to where the blades begin striking metal. My tractor is an Antonio Carraro and has the reversible seat/steering/controls station that makes it practical to mow going "backwards". This going backwards into brush gives me excellent vision and control, but the mower body on the wheel end is now the leading edge which makes it the first edge to contact brush. See reversed seat/controls and rotary mowing action of an Antonio Carraro with rotary mower in this video: YouTube - Antonio Carraro TTR HST 4400 tractor with bush hog rotary cutter

My plan is to make an angle iron frame structure to make a perimeter several inches away from the mower so as to be the point that first contacts saplings, brush, rocks, etc. Anyone else do something similar with their rotary mower? I don't see this modification causing a safety problem, but am asking my fellow tractor owners to point out any safety issues this outer perimeter brush knock-down guard can cause.
Bill in NC

 

[Gary Fowler]

I bent my housing backing into a nest of briars, shrub and small trees also and ripped some pretty good holes in the sheet metal. A stiff frame around it that ties all the way to the front would fix that problem along with some thicker sheet metal also. Other than the thin metal, the Howse cutter I have has taken some licks and still mows good, it just looks beat up in the back and once a rock got hung under the stumpjumper and now it has a circular raised area in the deck above it. Maybe someday I will just build a new 1/4" thick deck for it.

 

[Gary Fowler]

Safety wise, it makes no difference if th plastic housing spins with the shaft or not as long as it will stop spinning if something gets into it, which is almost an impossibility it it is all complete. IF something were to touch it and get wrapped up, then the plastic would then free wheel and allow you to pull back and free yourself. Chains all over are not necessary for it to function. If you can turn it by hand on the shaft without turning the PTO shaft itself then it is working correctly and doesnt need to be chained up. I dont believe the first guards even had chains and they were added by the safety police because of folk like those here that think it is unsafe because it spins with the shaft. It is a floating guard not an immovable guard.

 

[beenthere]

I find this thread interesting, but....

WHO in their right mind would have the rotary cutter (brush hog) engaged while they were working/jumping/moving around the PTO shaft ??

Back in the day when we had to work around the spinning PTO (feed grinder, silo filler, corn sheller, etc.) then the covered shafts were important.

I see absolutely no reason (other than a mfg. following a &%$#@ safety procedure) for a PTO cover, whether it is tied from spinning or allowed to spin. No one should be riding on the deck of a spinning/moving/engaged rotary cutter nor should anyone be off the tractor and nearby the engaged cutter. Be that as it may, I keep the PTO cover on, but I don't mess with the chains or try to keep it from spinning with the shaft.

 

[SPYDERLK]

Safety wise, it makes no difference if th plastic housing spins with the shaft or not as long as it will stop spinning if something gets into it, which is almost an impossibility it it is all complete. IF something were to touch it and get wrapped up, then the plastic would then free wheel and allow you to pull back and free yourself. Chains all over are not necessary for it to function. If you can turn it by hand on the shaft without turning the PTO shaft itself then it is working correctly and doesnt need to be chained up. I dont believe the first guards even had chains and they were added by the safety police because of folk like those here that think it is unsafe because it spins with the shaft. It is a floating guard not an immovable guard.

Exactly. A spinning PTO cover is no issue because it has very little friction on the live shaft and so little inertia that it stops easily and quickly should something touch it. You can easily stop it by grabbing it with a greased hand. Better that it spins tho so it looks dangerous. It wont do to become complacent - that actually is dangerous.
larry

 

[Cidertom]

While there have been good points about the safety cover spinning shouldn't be a problem, I would point out the posts where chains or mounts have been broken. If the cover is breaking these things, there may be enough force to pull in clothing. Once clothing is involved, it can wrap tight enought to choke onto the shaft and it's all bad from there on.

Yep, there is little reason for contact with pto shaft. But, then again those that read the safety forum rarely appear in it.

Some of the pto cases I've been on:
Grass wrapped on mower shaft, assistant tried to pull free. Fatality
Post hole auger not digging. Tried to pull down. Loss of both arms
Trying to catch a broken safety chain on grain hoist. Fatality
Stepping across spninning shaft. Loss of manhood and leg
Unknown reason, sweatshirt hood caught shaft. Fatality
been on a few others, but same vein. It only takes a split second...

 

[aczlan]

You can easily stop it by grabbing it with a greased hand. Better that it spins tho so it looks dangerous. It wont do to become complacent - that actually is dangerous.
larry

But who is going to test it? I prefer that the guard (at least on the shafts that have that type of guard) stay still, because that way I KNOW that it isnt bound up. Otherwise, there is no way to easily and safely test if it will stop spinning when you hit it.

Aaron Z

 

[SPYDERLK]

But who is going to test it? I prefer that the guard (at least on the shafts that have that type of guard) stay still, because that way I KNOW that it isnt bound up. Otherwise, there is no way to easily and safely test if it will stop spinning when you hit it.

Aaron Z

I certainly would -- even without greasing my hand on a plastic one. They would slip easily in the hand if bound. I have never encountered one thats bound. Very simple mechanism, reliably on call. Trustworthy as a steering wheel, but can gum up and damage itself if its slipping all the time. There is no easier and safer way to test them than stopping them by hand because it gives a feel for the health of their slip characteristic.
larry