Broke one of the most preached rules

[mbrule]

Lucky I only have a little YM135 and dad limited traction (sand). I was attempting to drag a cut maple tree up over a stone wall, I chained it to the top of my 3 point weight box, drove off and up came the front end!!!!!! Only came up about a foot, and then I was traction limited! Interestingly enough, I know better than to do this and usually chain to the drawbar, but it was off the tractor as I was about to use my rake, which the drawbar interferes with.

As told by everyone, I could not react even close to quick enough to prevent flipping, thank goodness It had such limited traction.

 

[texasjohn]

Glad you are OK..... it's amazing how quickly these things happen and so often it is because we are tired, in a hurry, or some "necessity" causes us to take an approach that normally would not be the case.

Thanks for the posting as a reminder to the rest of us!

 

[Soundguy]

Yep.. chaining to the toplink ( above axle ), and hooking to an imovable object shows you just how fast th machine can rotate around the axle.

glad you made it here to talk about it.

soundguy

 

[Thomas]

Whew..glad you came out okay.

Yep,just when one let's there guard down cold sweat appear.

 

[Renze]

I did convert my muck spreader to lower drawbar, even though most older equipment cam off factory with a tow eye at 80cm. Otherwise my 3011 would need front ballast on cultivated soil. The 4.5 ton spreader has enough tow eye weight to give the lightweight 3011 traction, enough traction to make the front axle float because of the rear axle torque, despite hooking it up 20cm below the rear axle.

Mostly, objects that are immovable when hooked to the lower drawbar, become movable when i hook it up to the high drawbar to get more weight transfer, =traction.

Funny enough, lower drawbar mountings (under the PTO shaft) are increasing in popularity since everyone has 4wd (mid 80's) but in the old days, everything had high drawbars. In Germany and Finland, high drawbars werent allowed so they had to do without the extra traction, back in the days of 2wd tractors.

With the ballast box in place, nothing would have happened, as soon as the ballast box hits the ground, you run out of traction and stall on the spot. I think thats what actually happened in your case too.

 

[CurlyDave]

Yep.. chaining to the toplink ( above axle ), and hooking to an imovable object shows you just how fast th machine can rotate around the axle.

You can flip a tractor chained below the axle, it is more difficult, but it can be done.

The only safe attachment point is on the correct drawbar for your machine (this is not the 3 point drawbar). The rearward extension of the drawbar is designed so that the drawbar end hits the ground and overturning torque goes to zero.

 

[JoelD]

I've seen guys take the chain or cable from the rear of the tractor, underneath the tractor and attach to the front of the tractor. Literally impossible to flip over backwards that way.

Would think this would put super strain on front axle though.

Joel

 

[Willl]

The rearward extension of the drawbar is designed so that the drawbar end hits the ground and overturning torque goes to zero.

Huh ?

 

[CurlyDave]

Huh ?

OK, I will elaborate.

When you pull something with a tractor, there is always a torque which is trying to overturn the tractor. The tractor is driving itself forward and the friction force between the rear tires and the ground is one component of this torque. The second component of the overturning torque is the backward force from whatever is being pulled. The torque is the product of the force and the height difference between the bottom of the rear wheels and the attachment point of the load. Under normal conditions, the weight of the front of the tractor is great enough that it provides a restoring torque which is greater than the overturning torque.

Now if the load is too heavy, or if it hits an obstacle, of if it is stuck to start with, the overturning torque will be greater than the restoring torque, and the front of the tractor will start to rise up in the air. Once this happens, things go south in a hurry. Human reaction time is just too slow to prevent an overturn.

If the load is attached to the drawbar, as the front of the tractor raises up, the back end of the drawbar will automatically be lowered. Some engineer at the factory has figured this out in advance, and the length of the drawbar is such that it will hit the ground before the front of the tractor is high enough to be dangerous.

When the tip of the drawbar is on the ground, the height difference between the attachment point and the bottom of the rear wheels is zero, which means there is no overturning torque. The operator will get the scare of his life, but good mechanical design will have saved him.

If you pull from anything other than the drawbar, you do not get this automatic torque reduction and there is a possibility of the tractor overturning.

There is a lot of misinformation out there about being safe if the attachment point is below the rear axle, etc. This is just plain not true. The lower the attachment point, the more safe is is, but only attaching to the drawbar is going to absolutely prevent overturns when going forward. Every time I read safety tips from some tractor authority that say attaching below the drawbar attachment point is safe, I cringe. They really need to talk to a physics professor or a tractor manufacturer before saying that.

 

[ShivasIrons]

Nicely done, CurlyDave.