sub soiler broke top link

[derek01]

I was in low range going very slow I think sub soiler hooked in under a root.

 

[Gator6x4]

My two cents worth. The subsoiler does not have a shear pin and the top link acted as one. If the top link had not broken the mounting point for the top link on the tractor would have been pushed in making for a very expensive repair. I have often wondered when looking at subsoilers without a shear pin or tripping mechanism offered at some retail locations how much damage would occur if a solid object was encountered. I would be thankful the toplink is what broke and explore other options on how to insure when the subsoiler encounters a solid object under ground it trips and does not break the tractor housing.

 

[derek01]

Bought it from Tractor supply I trhink maybe I will return it if I can

 

[Baby Grand]

My two cents worth. The subsoiler does not have a shear pin and the top link acted as one. If the top link had not broken the mounting point for the top link on the tractor would have been pushed in making for a very expensive repair. I have often wondered when looking at subsoilers without a shear pin or tripping mechanism offered at some retail locations how much damage would occur if a solid object was encountered. I would be thankful the toplink is what broke and explore other options on how to insure when the subsoiler encounters a solid object under ground it trips and does not break the tractor housing.

I have one of the TSC variety and have hooked onto something big a few times and only lost traction as a result. Once so abruptly that I thought I was going to go over the hood. Shear bolt of some sort would be prudent, and not terribly difficult to add. Since the top link is in compression, any off axis load will tend to buckle it - a slight bend would do it, as would excessive slop in the threads. When using mine, I try to adjust the hitch so the big beam/mast is as close to vertical as I can get it when it's at working depth.

 

[JohninCT]

I used the top hole, if you look closely at the break you will see that it was bent slightly. I understand that the 2 lower holes are for the draft but it seems that every time I adjust the yellow lever the hitch either will not go up high enough or down low enough especially when I am using rear lever for the 3 pt hitch.

If you are using the top hole you should not be adjusting the yellow draft control lever at all. Leave the yellow lever all the way forward (deepest setting) and control the raise and lower of your implement with the red position control lever only. Since your tractor has draft control (not all do) you should maybe give it a try when using a ground engaging implement like the subsoiler. It's hard to say, but the automatic draft control may have prevented the overload failure of your top link.

 

[jinman]

Derek, from the looks of your toplink break, I think it was being bent and compressed at the same time. I've attached an illustration of what I think may be the culprit.

When you are shallow with the subsoiler, the compression pressure is straight along the axis of the toplink. As the subsoiler goes deeper into the ground, the pressure becomes not only compression, but a bending force as well. I think your toplink is just not strong enough to take the bending force caused by your subsoiler, especially if you hit a root and it got an impact load.

 

[eray1066]

My son in law did this same thing earlier this year. He borrowed a subsoiler from another farm and used it with a 47 HP Challenger MT285B (same as MF 1547). The geometry of the three point hitch allowed the top link to go over center when lowered way down. The force allowed the subsoiler and the top link to be too straight and the angle between the subsoiler and the top link went from a V to an inverted V. When the 3 PTH was raised all **** broke loose. The solution was to change the hole on the tractor where the top link is attached so that it always is parallel to the lower lift arms.

Bought a new top link @ TSC returned the borrowed unit and bought a larger subsoiler at TSC. Lots of use ...... no problems.

 

[orezok]

Derek, from the looks of your toplink break, I think it was being bent and compressed at the same time. I've attached an illustration of what I think may be the culprit.

When you are shallow with the subsoiler, the compression pressure is straight along the axis of the toplink. As the subsoiler goes deeper into the ground, the pressure becomes not only compression, but a bending force as well. I think your toplink is just not strong enough to take the bending force caused by your subsoiler, especially if you hit a root and it got an impact load.

I don't see how a "bending" would occur as there is no moment connection if the clevis does not bottom out. The force will continue to be exerted straight along the toplink. However, the amount of force on the toplink would increase due to the change in relationship of the length of the "lever" below the 3 point connection and the diminished length above.

 

[oldballs]

Maybe the angle of the snag and the tension on the check chains were such that the "bend" occurred with the compression force. .... really, I'm no engineer.

 

[Baby Grand]

I don't see how a "bending" would occur as there is no moment connection if the clevis does not bottom out. The force will continue to be exerted straight along the toplink. However, the amount of force on the toplink would increase due to the change in relationship of the length of the "lever" below the 3 point connection and the diminished length above.

Exactly right - well put.

Since there's a "pinned joint", the top link is in pure compression, no bending load applied. Any looseness of the thread could allow a kink or curve in the toplink and add a bending load - so always tighten up the adjusting nut when running ground engaging implements. If the top link dead straight and rigid, then the risk to top link is only buckling due to compressive overload.

Angle above 90 degrees (call it A) between subsoiler & top link magnifies the compressive load - same principle that makes a chain binder work so well.
Compressive load in the top link = Load at the pin * (1/cos A).

I think the OP mentioned that the top link was already slightly bent before pulling the subsoiler, so the combination of bent link + binder effect of the angle was probably much. I don't think there's anything wrong with the subsoiler.