Flail Mower I Bent The Shaft On My Center Link

[sweettractors]

I'm curious why the top links are getting bent. I have never used a flail mower. Why are the top links bending instead of the whole 3 point hitch moving up when going over ruts/hills? Is something binding so the hitch does not raise?

I bet they are backing up hills or steep banks? Ken Sweet

 

[IslandTractor]

I'm curious why the top links are getting bent. I have never used a flail mower. Why are the top links bending instead of the whole 3 point hitch moving up when going over ruts/hills? Is something binding so the hitch does not raise?

As I understand it, it basically boils down to geometry, physics and beer bottles. If the rear of the implement is raised it will eventually be putting a compressive lever effect on the topping lift. Kinda like opening a beer bottle and just like a cap, the topping lift can bend. Initial movement would to some extent be taken up by the 3PT arms but if the lifting force continues from the rear the 3pt lateral arms become a pivot and pressure goes to the topping lift. I believe topping lifts are mostly engineered to hold things up (ie to withstand stretch, not compression) so that is why they are the week point especially when they are extended.

I'm no engineer but I did stay in a Holiday Inn last night.:thumbsup: Maybe one of our engineering colleagues will explain this a bit better.

 

[rjkobbeman]

As I understand it, it basically boils down to geometry, physics and beer bottles. If the rear of the implement is raised it will eventually be putting a compressive lever effect on the topping lift. Kinda like opening a beer bottle and just like a cap, the topping lift can bend. Initial movement would to some extent be taken up by the 3PT arms but if the lifting force continues from the rear the 3pt lateral arms become a pivot and pressure goes to the topping lift. I believe topping lifts are mostly engineered to hold things up (ie to withstand stretch, not compression) so that is why they are the week point especially when they are extended.

I'm no engineer but I did stay in a Holiday Inn last night.:thumbsup: Maybe one of our engineering colleagues will explain this a bit better.

I guess what is troubling to me is why the top link is bending instead of the 3 point hitch (including the whole flail mower) moving up. There should not be any down pressure on the hitch, so the mower and hitch should raise.

The tail wheel on a rotary cutter sits way farther back behind the hitch than the flail does. The stress on the hitch from a rotary should be much more than the fail mower... yet seems to follow to contours of the land without any problems.

 

[dennis33]

I'm no engineer but I did stay in a Holiday Inn last night.:thumbsup:

HAHAHAHA... I always wanted to use that line!

 

[IslandTractor]

The tail wheel on a rotary cutter sits way farther back behind the hitch than the flail does. The stress on the hitch from a rotary should be much more than the fail mower... yet seems to follow to contours of the land without any problems.

You are right, the risk should be higher with a long tailed rotary mower. As noted by someone else in this thread, the most likely action leading to a bent topping lift is backing up a mower up a hill or moving forward and having the tractor cross a big ditch. I don't know exactly how I bent mine but I have always suspected the boxblade.

 

[rjkobbeman]

You are right, the risk should be higher with a long tailed rotary mower. As noted by someone else in this thread, the most likely action leading to a bent topping lift is backing up a mower up a hill or moving forward and having the tractor cross a big ditch. I don't know exactly how I bent mine but I have always suspected the boxblade.

Ahh... I completely missed the backing up comment. Guess I should read a little slower...

Thanks.

 

[schrand]

Being an engineer (who didn't stay at a Holiday Inn), I'll take a shot at explaining why the top link bent.
I believe it all had to do with the mower being assembled wrong in the first place. The top link yoke was upside down/backward originally, as pointed out by TDVT. With that yoke on backward, there was a plate welded between the sides of the yoke beneath the top link (see the OP's photos). When the mower was raised, or lifted by backing into a hill, or whatever, that plate hit the top link and bent it. With the yoke installed correctly, that plate is on the rear of the yoke, not under the top link. I doubt it will be an issue from now on.

 

[dennis33]

The top link yoke was upside down/backward originally, as pointed out by TDVT. With that yoke on backward, there was a plate welded between the sides of the yoke beneath the top link (see the OP's photos). When the mower was raised, or lifted by backing into a hill, or whatever, that plate hit the top link and bent it.

BINGO!

I wish I took a picture of the plate on the yoke that showed the 'point of stress' on the top link. I'll post one this weekend after I return from the property in PA.

Everything looks good now!

Thanks again!

Dennis

 

[rjkobbeman]

Being an engineer (who didn't stay at a Holiday Inn), I'll take a shot at explaining why the top link bent.
I believe it all had to do with the mower being assembled wrong in the first place. The top link yoke was upside down/backward originally, as pointed out by TDVT. With that yoke on backward, there was a plate welded between the sides of the yoke beneath the top link (see the OP's photos). When the mower was raised, or lifted by backing into a hill, or whatever, that plate hit the top link and bent it. With the yoke installed correctly, that plate is on the rear of the yoke, not under the top link. I doubt it will be an issue from now on.

Now that I have looked at the photos again, I see what you are saying. I missed that when I was speed reading this thread.

Thanks.

 

[TDVT]

Hey Dennis, Glad that it's working better for you.

When I got my Caroni, it was right off the tractor trailer & I had to set it up myself. That's when I realized that the top link yoke would fit either way, making the slot horizontal or a random angle.

Then I remembered the slot conversation from the flail mega-thread & particularly advice from "Iron Horse" in OZ, so glad I'm could pass on his insights. Sort of a global effort, I guess.

Happy Mowing!