Rotary Cutter ROTARY CUTTER

[flINTLOCK]

When I run my rotary cutter on my fairly irregular fields, I have been using lift arms and hydraulic toplink. Unit goes as the tractor, up and down hills and depressions. That causes high and low spots in cutting path. If operated using lower lift arms only, it would more closely follow contour of the ground. Is that a safety hazard or no-no for other reasons??

 

[Robert_in_NY]

You need to lengthen the top link so the rear rides on the tail wheel more. You will still get some high spots if you are going over humps and other things but it won't be as bad.

 

[RoyJackson]

I've done the same as flINTLOCK (disconnecting the top link).

Theoretically, that cutter could flip up (pivot about the lower links) and do serious damage. The same would apply to those folks who replace their rigid toplink with chain.

If the field isn't too overgrown and you're familar with it, I think it would be reasonably safe to disconnect or remove the top link.

I've read about a lot of cutter accidents, but I've never read of a cutter flipping up and hitting the tractor or operator.

 

[Robert_in_NY]

I have flipped the MD 172 before as it has a linkage system that allows the top link to float but is still rigid to prevent it from flipping. I have caught a stump and the base of some thick brush and it has lifted the rear right up till it bottomed the linkage out. I would not suggest you run without the toplink but everyone can do as they want with their own tractors and equipment.

The first time you see the tail wheel 6' in the air will make you understand the importance of the rigid toplink.

 

[skipmarcy]

Don't know if it's feasible on your cutter to do but the harp on my cutter is slotted where the toplink pin goes thru - about a 6" long slot. This helps tremendously but will still leave a slightly high spot in a really big dip. The hydraulic toplink helps you readjust the pin to the middle of the slot for varying terrain. When I eventually have to replace my cutter, I'll definitely look for one with this same style toplink attachment, it has always given me a good cut.

 

[IslandTractor]

I've done the same as flINTLOCK (disconnecting the top link).

Theoretically, that cutter could flip up (pivot about the lower links) and do serious damage. The same would apply to those folks who replace their rigid toplink with chain.

.....

I've read about a lot of cutter accidents, but I've never read of a cutter flipping up and hitting the tractor or operator.

Wouldn't the PTO shaft prevent the cutter from flipping up more than a few feet? As the cutter pivots upward while attached to the side linkage, the distance between the gear box and tractor PTO housing gets shorter. Seems that it would shorten the PTO shaft as the rear flipped up and then (depending on length of the overlapping parts of the PTO shaft) jam into the tractor PTO stopping the cutter from continuing to rise. Don't ask how I know.

 

[vallyfarm]

That PTO shaft will bend/split or the U joints will blow out under anything other than rotational stress. I would NEVER take the top link off. Get two piecse of 1/4 in flat stock and drill holes in either end. Pin one end to the toplink point on the brushhog, the other end to the top link. This will allow plwnty of "slop" to adjust to ground contours, while still preventing the hog from flipping around onto you. ALWAYS safety first! Mike

 

[JoeinTX]

"Wouldn't the PTO shaft prevent the cutter from flipping up more than a few feet? As the cutter pivots upward while attached to the side linkage, the distance between the gear box and tractor PTO housing gets shorter..."


That was my thought too. The only way I can see that happening is if the mount pins on each side of the 3pt mount are actually higher than the PTO shaft as it runs from tractor to gear box. This would have the opposite effect (of forcing the two pieces of the PTO shaft toward each other) and might actually serve to pull them apart to some degree. Even at that, though, it doesn't seem like it would be enough.

 

[Robert_in_NY]

The pto shaft is a very weak item to rely on as a safety device.

 

[Farmwithjunk]

The pto shaft is a very weak item to rely on as a safety device.

AMEN!

Although I can't fathom a bush hog ever reaching the operators station, I'd just as soon not have a spinning pto shaft as the last line of defense.

 

[flINTLOCK]

I guess I could run chains to the drawbar from the top of the A-frame of the cutter which should prevent flipping??

 

[jsborn]

IMHO
If you are doing a lot of cutting in rough fields of unknown terrain I would think it advisable to have some sort of expanded metal shield across the ROPS. This would not only keep flying objects from the back of your head it would also keep the RC off of you should you have a loss of gravity that causes it to flip up that high with out a top link or with a top link chain.

I have noticed that most city/state units have these shields and they also use a lot of top link chains.

 

[flINTLOCK]

The chains from the drawbar to the A-frame or even the lift arms would not control extra stresses on PTO shaft, I guess. Hate to break that. My ground is very uneven.

 

[JoeinTX]

"The pto shaft is a very weak item to rely on as a safety device..."

It sure is and I don't read anywhere where someone was suggesting it as such.

The mechanics of getting a mounted shredder deck vertical to ground level while cutting is the odd thing here. I've cut a lot of ground, but, I've never come anywhere close to having a mower deck rear-up as described in the posts above. The PTO shaft would seem to give a good deal of warning of this "problem" pretty quick as it buckles and binds and joints fail as the deck comes up.

One net positive with having a direct, non-live/independent PTO is that when things get hairy, applying the clutch stops everything going on.

 

[Robert_in_NY]

When it happens it happens quick. It isn't something that builds up over time and I know for a fact that it can happen. The reason I even knew there was a problem is that the rigid top link bottomed out and stopped the tractors forward progress leaving the cutter in the semi-vertical position.

And IslandTractor said this "Wouldn't the PTO shaft prevent the cutter from flipping" and you agreed in a later post. What role would the PTO shaft be playing if you were relying on it to "prevent the cutter from flipping"? Seems like it would be considered a safety device in that role.

One thing I notice is that a lot of people seem to think a 540 pto shaft is a solid setup. It is a very weak system which is why most tractors over 100hp run 1000 pto systems. It is very easy to destroy a 540 setup but you need to make a concentrated effort to destroy a 1000 setup.

 

[IslandTractor]

And IslandTractor said this "Wouldn't the PTO shaft prevent the cutter from flipping" and you agreed in a later post. What role would the PTO shaft be playing if you were relying on it to "prevent the cutter from flipping"? Seems like it would be considered a safety device in that role.

I wouldn't say the PTO was a "safety device" but rather that it's presence would tend to prevent the cutter from flipping past a certain angle and therefore would prevent entry into the operator's space. It may provide a margin of safety in that sense but I don't think anyone is arguing that the PTO is designed or spec'd to serve as a primary or even secondary safety device.

 

[Flywheel]

Get two piecse of 1/4 in flat stock and drill holes in either end. Pin one end to the toplink point on the brushhog, the other end to the top link. This will allow plwnty of "slop" to adjust to ground contours, while still preventing the hog from flipping around onto you.

Best idea of the day!

My JD LX5 has a feature built in - it is not a slitted toplink point, but a similar mechanism - basially, when you set up your cutter, you try to ensure that the toplink is in the center of the slot so that it can tilt with the contour keeping the rear wheel on the ground.

This idea will work perfectly for this. BTW - I would htenk the flat stock would only need to be about 4 inches long, eh?

 

[Robert_in_NY]

Islandtractor, from personal experience, a 540 pto shaft will provide no such protection from a rotary cutter flipping. If you hit something solid enough to flip the cutter up the shaft will fold like a wet noodle. They are very weak and are a poor design but a design that has been around for a while so it will stay as all the tractors have been designed for it for a long time. The poor performance of the 540 pto system is why they switched to the 1000 pto system for larger tractors. They would just tear the 540 systems apart as they don't have the strength. If you get a chance, look at the pto shaft of a 540 and compare it to the shaft on a 1000 system and you sill see a huge differerance.

The shaft does work fine for small hp equipment as long as it stays straight. If you start to put any stress on them though it doesn't go well and may cause more damage in the process.

I think chains are better then nothing at all because you still have the top link hooked up to the A frame and if the cutter did flip up it would hit the A frame before it hit the tractor.

In the end though, rotary cutters are also known as rough cutters for a reason. They are not designed for finish work and if the OP has a lot of dips and humps he may be better served buying a pull type cutter which will follow the ground contour better then a 3pt.

 

[John861]

Another cheap top link solution is to run a chain through a pipe that is a few inches shorter. This will act as a limiter of sorts, so the mower can't flip up, or the tractor can't flip back as far. You can fine tune the pipe length to suit the unevenness of your land.

-John

 

[Grrrr]

I have thought about the bush hog flipping up before on our tractor. Our bush hog has chains going from where the top link attatches to the bush hog down to the back of the bush hog.

I never have a problem with the cutter not following the ground. I make sure the chain has plenty of slack and it seems to wor well.

I think if one of the front corners caught on something it would slide of to the side and not rear up. If you did hit something square on it could cause the cutter to rear up. However I dont think it would get the operator as the top link is attatched to the A frame and would keep the cutter back.

This is what our cutter look like (We call them toppers in England)

You might be able to do something like this, swapping the metal straps for chains?