Flexible top link for bush hog?

[Syncro]

How important is the flexible top link shown in this pic? I notice some people use either a chain or this flexable link.

I've used bush hog type cutters for many years without one with no apparant problems, however I may have been in error. /forums/images/graemlins/shocked.gif If so I'd sure like to know what the reason is to use one. /forums/images/graemlins/confused.gif

 

[beenthere]

If your ground is perfectly flat, no need for one. If you carry your rotary cutter, and don't set it on the wheels, then no need for one.
But otherwise, it's much easier on the cutter when uneven ground is trying to push up the rear of the cutter, and restricted by a fixed linkage through the top arm.
For me, a chain works better and with more flexibility than the short flexible link shown.
All your choice, however.

 

[tawilson]

Good question. My JD didn't come with it, but looking through the manual I saw a pic of it. I went back to the dealer, some of their mowers came with and some didn't. I got one and use it. I presume it's to provide some slack for going into and out of depressions. For that matter, I forgot my toplink when bringing my york rake to where my tractor was, used a chain instead and it worked just fine. So how come we use toplinks instead of chains. Not trying to steal your thread, jiust wanting to further the discussion.

 

[tawilson]

Gosh darn you, beenthere. I take too long thinking and composing and not trying to sound stupid, then you post whilst I'm doing all that and make me look dumb anyways.

 

[Syncro]

<font color="blue">....it's much easier on the cutter when uneven ground is trying to push up the rear of the cutter, and restricted by a fixed linkage through the top arm.... </font>

Roger that, makes sense. I wonder though since the side arms on the 3pt will freely move up anyways why there would be any strain. It would seem if the back wheel were to raise over a bump that the entire deck would pivot on the lower arms? /forums/images/graemlins/confused.gif

I can see where some flex would make for a better more even cut, my concern was that I may have put undue strain on the tractor housing, but from what you say probably not.

 

[beenthere]

</font><font color="blue" class="small">( Gosh darn you, beenthere. I take too long thinking and composing and not trying to sound stupid, then you post whilst I'm doing all that and make me look dumb anyways. )</font>

/forums/images/graemlins/wink.gif Sorry, but nothing you said makes you look 'dumb' IMO. /forums/images/graemlins/wink.gif
Looks to be supportive of what I said.

Syncro
I think with no chain or loose link in the upper support system, when the rear wheel of the rotary cutter raises, it puts a lot of undue compression on the 'stiff' linkage. In fact, it will bend the support bars (strap steel) that connects the top link to the rear of the cutter deck (at least it did on my Deere RC). I replaced these 'bars' with chain.

 

[Farwell]

I was thinking about using a chain instead of my top link until I read one of the TBN threads that posted an article about someone having the brush cutter going over something that made it flip up and nail the operator. Not sure if this is possible but the way it was explained made me change my mind and continue using my top link.
Farwell

 

[greg_g]

</font><font color="blue" class="small">( How important is the flexible top link shown in this pic? )</font>

Unless you're mowing a billiard table, it's extremely important. With that type, you have a transport position and an operating position. For transport, you shorten the toplink until it's drawn up tight - with the flexible bracket pointing towards the tractor. Once you get to where you're going to mow, you lengthen the toplink so that the flexible bracket is pointing straight up. That permits the bracket to move forward and rearward as the mower deck floats with the terrain. That way there's no undue strain on the metal straps mentioned above either. When you're done, shorten the toplink, lift the mower, head back to the barn.

FWIW, I don't think chain makes a safe permanent replacement for either the toplink or rear lift linkage. The only thing I use chain for is if/when a tractor needs lower lift arm stabilizers.

//greg//

 

[MMM]

</font><font color="blue" class="small">( brush cutter going over something that made it flip up and nail the operator )</font>

It's what cutter doesn't go over that causes front flip. Like hanging it up on hidden stump. Large cutters can be hard to load on some trailers if there isn't a flex point somewhere also. Some, like mine, have chain from A-frame to the rear for flex.

 

[Farwell]

I just finished Beenthere's thread and saw the photo of his brush cutter backed up a bank. If you haven't checked it out, take a look. This is what I would like to do in a couple of areas on my property but do not see how I can do it with out using a chain on my top link and am nervous about the strain on my PTO link. I will have to do a little experimenting. I have seen the A-frame chain set up and will give that a try.
Farwell

 

[Slamfire]

The strapping that forms the supports on my cutter, has about 10" of chain let into the middle of each one. That keeps them from being bent. /forums/images/graemlins/smile.gif

 

[N80]

I have the JD LX-6. It has a fairly complicated floating top link. It is hard to describe but I've attached a picture below. I think it works extremely well and my property is rough. Nothing is flat. Nothing is even.

I can't get my brain around all the geometry but I don't see how a chain set-up would improve on this design much.

I don't use an iMatch or other quick hook-up, just the basic 3 point.

 

[beenthere]

N80
Your top link flexibility should work well, and better than the short 6" plate links that mine came with. Also, yours is fixed up to be iMatch compatible, as the top hook picks up the bushing just under where your toplink is pinned (arrow A is almost pointing to that bushing). Then the flexible link mechanism works the same for you. If I had that, I wouldn't need the chains which do the same thing.

 

[Soundguy]

</font><font color="blue" class="small">( seem if the back wheel were to raise over a bump that the entire deck would pivot on the lower arms?
)</font>

look at the 3pt geometry.. if the back goes up, the deck cannot pivot on the lower pins due to the rigid 3rd link connection. That's the main reason for the seime rigid link.

My KK mower has one like pictured, and my Howse has a slot of the toplink pin to travel in.. serving the same purpose.

Soundguy

 

[N80]

I tried mowing with the top link disconnected and this works pretty well, even on fairly hilly terrain, since the mower is free to rise and fall. The problem with that is smaller holes, etc that the back wheel can drop into and cause the mower to drop down and the blades to dig in.

I've heard about the possibility (I don't know if it is real or not) for the mower to hit something and bounce up and injure the driver if no top link is attached. Seems unlikely to me, but mowing without it is too hard on my place anyway, so it stays connected to the top link. Without the top link attached the back of the mower would definitely hit my back tires if raised too high.

 

[Syncro]

<font color="blue"> if the back goes up, the deck cannot pivot on the lower pins due to the rigid 3rd link connection. </font>

Sure it can, the three point has ball joints at each end of all three links. A top fex joint just makes this movement much easier, preventing undo stress on the rigid struts of the cutter.

I agree it's needed and I can now see why. That said, I also wonder about replacing the rigid 'straps' with chain as this would cause the cutter to rotate on the lower arm pins and not at the ball joints.

It would seem that the best way to allow free movement would be either a chain or other flexable linkage on the top link.

Anyway, thanks to all for shedding some light on this. I'm going to fabricate some sort of flexable top linkage, probably using chain. The vast knowledge bank on this site is a wonderful resource. /forums/images/graemlins/grin.gif

 

[Farmwithjunk]

</font><font color="blue" class="small">( I was thinking about using a chain instead of my top link until I read one of the TBN threads that posted an article about someone having the brush cutter going over something that made it flip up and nail the operator. Not sure if this is possible but the way it was explained made me change my mind and continue using my top link.
Farwell )</font>

I'm not even going to try to attemt disproving this ever happened, because ANYTHING is possible. BUT... I'm leaning towards the "suburban legend" idea myself. In all my years of dragging bush hogs over stumps, rocks, and ditches, I've never had one attempt to flip up more than a few inches above normal.

I'd venture to say chains, or some other flexable link is SAFER than forceably holding a mower deck to the ground if and when an obstruction is met.

 

[have_blue]

FWJ,

Can't quite visualize it, but I think most bush hogs would hit the rear tires before they hit the operator.

Edit:
I guess quick hitch could make things a little different though.

 

[Farmwithjunk]

</font><font color="blue" class="small">( FWJ,

Can't quite visualize it, but I think most bush hogs would hit the rear tires before they hit the operator.

Edit:
I guess quick hitch could make things a little different though. )</font>

I'd guess the PTO shaft would slow it down a bit first, then IF it was to raise up farther, it would find the tires next. Thing is, I don't see it getting that far.

 

[beenthere]

Would this picture help? attached