Flexible top link for bush hog?

[Farmwithjunk]

I've got a 2 year old Woods BB840 mower. It has a built-in flexable link where your chains are located. I routinely mow the dam to a pond on my farm. I start at the top, turn left, and drop down the dam. At the bottom, I end up in a position about like your picture. Without that much "flex", there'd be some bent parts.

For the life of me, I can't imagine RIGID mounted mowers working on even the flattest of land.

 

[MMM]

I think the tires would save you only if lift arms didn't extend past them. Look at the angle in Beenthere's pic. Might could get a tailwheel toupee even with ROPS. I haven't been nailed by a cutter either, but have had rear of one come up about 3' when hanging the front edge on a stump.

 

[RalphVa]

If you look at that picture of the JD LX6, I think you'll see that the top part of the linkage frame on the LX6 will keep it from flipping up. The top part of the frame will hit the back of the tractor before the main part of the brush hog will. Some brush hogs will be different, of course, and maybe allow the frame of the brush hog or PTO to bounce all the way up to the operator, but it's very likely a stretch for this to happen to most (think the PTO shaft will maybe even keep this from happening).

The linkage on my LX4 is identical to that on the LX6. It IS NOT flexible enough for the hills and uneven terrain that I run it over. I have a chain attached between tractor and LX4 most of the time. The chain is short enough to keep the LX4 from dropping off the side of a creek bank but will allow the blade to dig into the dirt when the wheel on the LX4 goes off the bank or into a hole. Unless one hits a rock, there's no problem. The hydraulics just slow the blade down (a big rock will, too). Maybe if you had a really high hp tractor, you might have to worry over this more.

I keep both the chain and the top link attached onto the top link part of the LX4; they fit side by side. I can very easily disconnect the chain from the tractor and swing the top link over and connect it for transport or for when I need the full weight of the LX4 back there to counteract weight in the FEL.

Ralph

 

[N80]

</font><font color="blue" class="small">( The linkage on my LX4 is identical to that on the LX6. It IS NOT flexible enough for the hills and uneven terrain that I run it over. I have a chain attached between tractor and LX4 most of the time. The chain is short enough to keep the LX4 from dropping off the side of a creek bank but will allow the blade to dig into the dirt when the wheel on the LX4 goes off the bank or into a hole.)</font>

That's confusing to me. I'm just not sure I understand the need for a chain if you already have a floating top link. It just seems to me that if you have the top link on your 3pt hitch set correctly you don't need a chain to limit downward travel of the mower.

When I hook mine up I set the mowing height to nearly the lowest point that I'll likely need with the floating top link in the centered position as shown in the diagram. Then I set the top link on the tractor so that it will allow the mower to drop down only as far as the play in the floating top link and no further. This way the mower can drop a small amount to follow the terrain, but will not drop down enough to scalp even if you pass over a hole or little valley.

Works for me anyway.

 

[Soundguy]

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

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.
)</font>

Hook up your 3pt mower. now.. lift up on the back of the mower.. the back of the mower -cannot- flip up ant have the front pivot on the lower 2 arms and have the tailwheel touch the canopy of your tractor _with_ the toplink in place. The toplink will make the mower lift up on a close to level plane, instead of pivoting on the 2 lower arms and flipping up.

That's what I'm saying. The ball swivel ends have nothing to do with the picture. The flexible portion of the toplink just gives that much more play when lifting or dropping.

Soundguy

 

[RalphVa]

The purpose of the chain instead of the top link is to allow the brush hog to move UP more than the flexible top link will allow. I've had the tractor move completely off its rear wheels before I went to the chain in place of the top link. There's only about 2" flex in either direction (up/down) on the LX4/6 linkage. This is not enough for really uneven terrain. I just mentioned the length of the chain to only allow the brush hog to drop a limited amount. Another limit on the chain length might be to keep the PTO from hitting the deck. You want it short enough to keep this from happening.

I'll make another pitch here. The IDEAL top link would be something like an automotive shock absorber.

Ralph

 

[N80]

</font><font color="blue" class="small">( There's only about 2" flex in either direction (up/down) on the LX4/6 linkage. This is not enough for really uneven terrain. )</font>

While I haven't measured the flex, I'd say I've got considerably more than a total of 4 inches, and quite frankly, it has worked perfectly in my one month of ownership and has done so on terrain as rough as I can imagine using a mower on.

But, that's neither here nor there, a chain will certainly allow more upward travel and you are quite right about a shock type assembly being the ideal.

 

[beenthere]

</font><font color="blue" class="small">( IDEAL top link would be something like an automotive shock absorber )</font>

Or a hydraulic top link that could be put in float when not 'traveling' with the cutter raised.

 

[Solo]

I saw a bush hog stand on its end once, but it did not hit the operator. Both lower link pins fell off and caused it stick on a stump. The upper link kept it from hitting the tractor.

Solo

 

[slowzuki]

I have a caught the front edge of the bushhog on a stump and had the tail wheel kick before.


I've also had the flexible link "bottom out" and shove the tractor around. The tailwheel is so far out it puts a tremendous load on the toplink when it can't lift higher without lifting the whole deck. This is especially true when mowing quickly in a field hitting chuckholes etc.

 

[RobJ]

Like N80 said, my brother in law uses a 4' hog on a L175 all the time with no toplink installed. The light tractor gets jumpy when traveling and the hog all the way up. When driving this combo up and down a draw (sort of steep climb) the fronts will not bounce around.

 

[djradz]

Yes, I would think without a top link, the deck pulls somewhat similar to a "trailer-type" mower. I've never heard of these flipping up on the operator either. Just seems this whole discussion about dangers from a loose, flexible, chain or NO top link are greatly exagerated.

 

[Soundguy]

Here's something to think about.. without the toplink, you still have the pto shaft attached.. that is also going to limit ( in a destructive way ) the max upward pivot-travel the mower deck will have... that is untill something gives way!

Also.. witht he toplink removed.. and the mower still attached to the 2 lower links it WILL NOT travel like a pull mower, as it is still semi-gigidle mounted. If you make a turn.. the mower swings wide. On a trailer/drawbar mower.. when yuo turn.. the mower banks..

Soundguy

 

[N80]

</font><font color="blue" class="small">( Also.. witht he toplink removed.. and the mower still attached to the 2 lower links it WILL NOT travel like a pull mower, as it is still semi-gigidle mounted. If you make a turn.. the mower swings wide. On a trailer/drawbar mower.. when yuo turn.. the mower banks..

Soundguy )</font>

Exactly. It follows the terrain like a pull-type but does not turn like a pull type. If you had really even terrain (it follows slopes just fine) it seems like it would work perfectly. But if there are pot holes and irregularities it will scalp since there is nothing to limit downward travel.

Not to hijack the thread (but we have beat this one to death /forums/images/graemlins/wink.gif ), what have you guys heard about PTO shafts breaking at the mower end? Is it possible for a flailing PTO shaft to hit the driver? On a 3 pt unit the shaft travels under the hitch mount 'A'. On the pull type mowers that I've seen, there is a bearing that the shaft goes through up near the hitch. All this seems like it would keep one from flailing about too much, but it seems like I've heard of this happening.

 

[Soundguy]

Can't speak for others.. but if the shaft on my 10' mower came apart.. by the time you figure it is half height.( 2 pieces ).. it would not be able to peg the driver... probably destroy fenders, remotes, lower arms/drawbar and tires quite nicely though.

Soundguy

 

[Varmintmist]

Cant say they are the same now but the Bush Hog I bought used is set up with a chain from the toplink to the rear wheel.

It will pivot around the lower links and not bend.

 

[slowzuki]

From our haying partners experience, the yoke at the tractor will very quickly smash while throwing the sliding part of the shaft or alternatively it stalls the tractor or slips the pto clutch if you have one.

Yes, they have bought a lot of pto pieces. And they've learned to put a lockpin in drawbar pins. A tedder passing you going downhill while spinning at 540 rpm isn't fun!

Ken

 

[djradz]

</font><font color="blue" class="small">( Also.. witht he toplink removed.. and the mower still attached to the 2 lower links it WILL NOT travel like a pull mower, as it is still semi-gigidle mounted. If you make a turn.. the mower swings wide. On a trailer/drawbar mower.. when yuo turn.. the mower banks.. )</font>

I know we're beating this one to death, so I'll take one last stab to be sure its got no life left. ... I brought the pull-type argument up, not because the decks would pull the same, but to illustrate that even with only the single connection of the pull type, there's no chance of a major flip-up. Yes, if the obstruction is off to the side, the deck will likely move to the other side around the object, but if the obstruction is near the center of the deck, such as a large stump that clears the underside of the tractor but not the deck, I doubt the deck will do anything other than ride right up over it, or do some very serious damage.

Also, I think many might think the trailering scenario provided by the three-point, minus the top link, is very nice. I can do an awful lot of weaving in and out (around trees, poles, etc) with my RFM that I would not be able to do with a trailer-type (draw bar or hitch) type deck. You kind of get the best of both worlds. (note: for convenience, I usually mow with my top link connected, but loose enough to let the top link mower connection, flex to the maximum.)

 

[Syncro]

I posted this original question a while back, as to why the need for a flex top link. Today I had to mow the last pasture on our land so I hooked up my bush hog sans any flex top link, and before I started I decided to try a little experiment. I parked the tractor on level ground and lowered the hog. I next took a wood lever and proceeded to raise the back tire of the hog. Well, the deck just pivioted on the 3 pt lower links any easily moved up and down. So to my dumb eye it looked like the tale wheel would do the same on uneven ground, that is move up and down without any flex top link.

Now I know the rest of the world can't be all wrong, so what am I missing here? If the tale wheel will freely follow the ground then whats the point? /forums/images/graemlins/confused.gif

 

[beenthere]

You got it. It'll work.
No need for the top link if you want to run your RC that way, and do not want to lift it off the ground for faster travel.

Just don't raise the 3pt arms so much that the front edge of the deck contacts the PTO shaft and bends it.

But I like to pick mine up so the rear wheel doesn't touch the ground for 'cross country' travel, and I adjust the rear chains so the PTO shaft doesn't touch the front deck edge when the 3pt arms are raised. /forums/images/graemlins/wink.gif That's all the chains do for me, is provide that freedom of movement.