LD1
Epic Contributor
Any solution to the question I posed?
Preventing tractor back flip
- Thread starter retiredmgn
- Start date
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Any solution to the question I posed?
Something must bend or brake.
The geometry REQUIRES that the tires roll backwards as the nose comes up. If they are not allowed to roll backwards, the nose cannot come up. If the nose cannot come up, something in the drive train between the unlimited source of power and the frozen contact patch, or something in the linkages controlling the geometry (chain, drawbar, case, axle housing, wheel rim, etc.) must fail.
xtn
hawkeye08
Elite Member
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AGGIE00
Gold Member
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- May 9, 2010
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- 449
I can add some experience to this one. I stuck a deere 450 lgp dozer clearing on my property. All I had to try and get it out was my old deere 2640. My wife came over to help and drove the tractor. I didn't have a pin to attach the chain to the drawbar so like an idiot that knew better I attached it to the centerlink bracket and to the centerof the dozer blade from the bottom. I told my wife to go slow and if she felt it begin to raise up in the front push in the clutch. Of course the front raised up and in her panic she couldn't push in the clutch and the tractor went to a 45 degree angle when the tires started to slip alternately causing the tractor to bounce from side to side. I got off the dozer with it still in gear and ran to the tractor and pulled the kill knob. It was a moment of panic and having known better made it so much worse. The next attempt involved rigging the chain to the drawbar and attaching the other end to the corner of the dozer blade. I let my wife pull forward until the tractor dug down to anchor itself and rotated the blade which worked 2 feet at a time until the dozer was out. From the drawbar the tractor never raised up.
LD1
Epic Contributor
We agree:thumbsup:
The situation I posed CANNOT be solved. IF everything is unbreakable, and IF you hav unlimited power, and IF the tires cannot move, there is no solution because
1. unlimited power says the tractor will flip, but...
2. the unbreakable chain sats it stays put:confused2:
If the tires cannot rotate backwards the front CANT raise []
and THAT is MY argument as to why the tractor cannot flip. Because I dont believe the tires move backwards when under load and trying to drive forward regardless of all these scenerios we have posed.
So to sum it up, YOU believe the tires roll backwards and THAT is how it can flip. Thats your belief and you are entitled to it.
MY belief is that the tires do NOT go backwards and that (above scenerio that you agree with) is why it cannot flip.
Again, I think we can agree to disagree and part ways on this matter. From one hard-headed-stubborn-SOB to another:thumbsup:
AGGIE00
Gold Member
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In order for the tractor to flip on flat ground the point from which you pull would have to originate above the center of the axle.
Yup that does seem to be our point of separation. Guess I'm just gonna have to fab up a model and make a video of it for you. Actually I don't know if my stubbornness surpasses my laziness enough to do that.
LD1
Epic Contributor
:laughing::laughing::laughing:
SPYDERLK
Super Star Member
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- Feb 28, 2006
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- Tractor
- JD2010, Kubota3450,2550, Mahindra 7520 w FEL w Skid Steer QC w/Tilt Tatch, & BH, BX1500
LD1, yes I believe what I wrote previously about frozen tires. But its like changing the subject to go there. We are not talking about tires that cannot move, but instead tires that will not slip. The tire and chassis can move by rolling back as they have to to allow for the substantial chain takeup that occurs while the tractor rears up an amt allowed by a short drawbar [a long one wont pull in much because back tip is limited as it approaches touchdown]. In either case much of the takeup caused by the bar swinging down and under is fed back by the tractor axle moving back and with the tire roll allowed by the lifting front end. [Lets keep the chain long to avoid a needless complexity.] Now if your drawbar is short .. say lacking 2" of reaching the ground at the closest in the arc it would swing in a flip, then at the very least point you will have 1/6' x traction force net backtip in your "dueling" lever system. You have gravity acting on the forward located tractor COM that can give a little help to the disadvantaged short drawbar, but with unlimited force available at the ground its going over no matter how much the COM can offset. Cross up some different length wrenches. I think itll help give you the idea.
... Oh yeah -- also back tips are not favored by a running start since the COM is way above the drawbar hitch point, and the sudden deceleration at the end of the tether would thus tend to nose the tractor down. Back tips are pure grunt work.
larry
... Oh yeah -- also back tips are not favored by a running start since the COM is way above the drawbar hitch point, and the sudden deceleration at the end of the tether would thus tend to nose the tractor down. Back tips are pure grunt work.
larry
JoeL4330
Platinum Member
Hmmm...I wonder if the tires can move backward but not (not) rotate backwards? Easy to think of situations where tires move but do not rotate: get your pre-anti-lock-brake vehicle up to speed, lock the brakes...skid--each tire (indeed, the whole vehicle) moves but none of the tires rotate ...just sayin'