Tractor Rollover

[WinterDeere]

But that would be on a static object once that object is in motion none of the collected data would apply.

A static tip point is all you're ever going to get, I think. Rotational velocity and moment will impact how far you might tip when rolling over an object at speed, but introduces too many variables to be of actual practical use to anyone. Besides, your cheap inclinometers are static instruments, only.

 

[dadohead]

A static tip point is all you're ever going to get, I think.

Yes, static stability test is all you get. Mowers follow ANSI B71.1 stability test on a tilt table: 30° longitudinal, 20° lateral. There are no mandatory tests for tractor. Manufacturers do internal testing and will provide guidelines with best practices... too many variables. It remains YOUR responsibility to stay safe.

 

[MossRoad]

The manual on my Kubota L5030, in the safe operation section only says to set the wheels as wide as they go for widest practical application ... Nothing about reduced weight capacity or increased wear ... The wheels have adjustable spacing, I have them at there widest.

My Massey Ferguson GC 1725 MB doesn't have adjustable wheels, and doesn't say anything about wheel spacers, I have 3" spacers on the back, and 1.3" on the front ... Haven't noticed any "wear" or problems in the 735+ hours I have on it, I bought it new ...

My "seat of the pants meter" went off at this point, my front tires wouldn't pull/steer up hill in 4X4 .. the 5' brush hog on the back is a bit heavy for it, and I had forgotten to put rocks in the bucket like I normally do for front ballast ...

View attachment 4618507

I gingerly got off the top side holding onto the ROPS hoping it wouldn't tip over, it didn't ... I gave it a little "shake" ... Rock solid ... Gave it a "PUSH" , still stable ...

View attachment 4618508

You can see how the front tires had spun a little trying to pull me up ... I probably could have just backed up, but I didn't feel like it, plenty of weight on the back, and down low, tires are filled, 70 Lb steel wheel weights on each side, and 275 Lbs mounted on the BH frame, plus the brush hog , rear tires had not broken traction ... Once I added a few rocks, the front tires could steer, and I just drove out!

View attachment 4618509

I can easily mow this hill sideways in 2 wheel drive with this Kubota, rear tires are not filled, but the MF needs to be in 4X4 ...

View attachment 4618510

View attachment 4618511

This next picture is the same place as the previous picture, the little tree near the rear tire is the same as the one 10' to the left in the previous picture, with the 5' brush hog I can mow this in 2 wheel drive, but with the 90" finish mower, I need 4X4 to pull it back up, it weighs twice as much, and all the weight is on the ground ... I mow sideways on the hill until I get to that little tree, then go up and down to get beside it ...

View attachment 4618513

View attachment 4618514

Now it would be interesting to take a 2x4 that's as wide as your tire tracks and lay it across the areas you were concerned about, then stick an angle finder on it to determine the exact angle it was on. Do it in several places if you do it.

 

[ultrarunner]

I hope she doesn’t fly…

 

[dieselscout80]

Retired tractor engineer here. I used to study accident reports. Know that many of the rollover type accidents start as a "runaway" then end in a rollover.

Soooo, pay attention when decending a hill with that load. Diff-lock is the one feature you use  before it is needed. Without, all it takes is one tire to break traction and the other will "freewheel". It feels exactly like you shifted to neutral. Pay attention on decents, slow down, and engage diff-lock before the decent. Good discussion! Hope this helps!

Thanks!!!

I had not thought about using the differential lock on downhills.

I do engage 4wd. Once I forgot to shift into 4x4 with a 55 gallon drum of corn on the loader and slid all the way down, which fortunately was clear all the way down.

 

[LouNY]

A static tip point is all you're ever going to get, I think. Rotational velocity and moment will impact how far you might tip when rolling over an object at speed, but introduces too many variables to be of actual practical use to anyone. Besides, your cheap inclinometers are static instruments, only.

A few years ago at an ag show the Extension service had a tractor cab on a tilting axis. You would climb into the cab and they would tilt it with you sitting in it and then they would ask you to push the button on the wheel at the max that you felt safe at. I have no idea of what equipment tilt that they had compiled their information from. I rode it to a bit over 20 degrees, when I got out they said I was about to the max. I've only been that close a couple of times with larger tractors. A CIH 7120 on one miserable field when chopping with a pull type forage harvester it was an sidehill uphill turn straddling some rock ledges, then on the outher end the turn was to the up hill while coming downhill with a load behind you. It would get your heart to pumping when to stay in the seat you had to move your foot to the low side of the cab.

An inclinometer is an "active" device in that it is providing you with a real time reading.

 

[WinterDeere]

A few years ago at an ag show the Extension service had a tractor cab on a tilting axis.

That's pretty cool. Good demonstration.

An inclinometer is an "active" device in that it is providing you with a real time reading.

It is not, because to be classified as anything other than static, the instrument ramp rate + settling time would need to be an order of magnitude faster than the system it is measuring. Does the bubble on your inclinometer move through the fluid in the sight glass to its final valid position, 10x quicker than your tractor can roll with gravity? Does the digital inclinometer reading ramp and settle 10x faster than 40 degrees per second, or whatever a tractor rotating itself under power might achieve? Almost certainly not.

For an example of the difference, think it it as trying to use a voltmeter instead of an oscilloscope to measure instantenous voltage on an AC waveform. The voltmeter might work for measuring instantaneous time-varying voltage, if the frequency is below 1 cycle per second. But the needle on an analog gauge or the input capacitors on a digital meter will prevent it from doing the same at 10 Hz or 50 Hz. Voltmeters provide a "real time reading", by your definition, but they are most-definitely "steady-state" or "static" measurement devices.

 

[MossRoad]

From what I've heard from some PowerTrac owners that have visited the factory in Tazewell, VA, they have a slope mower sitting on a 45 degree angle in their showroom...

 

[SmallChange]

It is not, because to be classified as anything other than static, the instrument ramp rate + settling time would need to be an order of magnitude faster than the system it is measuring.

Actually, I think this speaks to a useful instrument tractor makers could include. It'd be a meter that takes into account both static gravitational effects and dynamic inertial effects. In fact, it could even take loader height into account, and even the load itself, perhaps by watching hydraulic pressure when the loader is going up.

This is a complicated thing. For one thing it would have to be done with thorough understanding of the tractor's weight distribution. It's not something we could practically do ourselves. But if there are lawsuits out there, this might make huge economic sense for a manufacturer.

About 45 years ago I worked with some guys who designed systems with microprocessors in them. Microprocessors are common and cheap these days -- for example, they are the reason I can't understand the user interface on our goddam toaster. But back then, this was rare. These guys were working on a project to monitor the movement and forces on cranes, to prevent them tipping over. One situation they were working on concerns having the boom nearly vertical, lifting a load near the crane body, and then starting to lower the boom. It's very tricky, because stopping the boom will add tipping force from its inertia. An operator can start lowering the boom and put the crane in a condition where there is no way to avoid tipping a few seconds into the future, even though it is stable when the operator does this. If they could solve that problem back then, imagine what a manufacturer could do today.

I have never tipped. But I don't know if my worst near miss was 10% of the way to tipping, or 90%. Sure wish I knew.

 

[RayIN]

Actually, I think this speaks to a useful instrument tractor makers could include. It'd be a meter that takes into account both static gravitational effects and dynamic inertial effects. In fact, it could even take loader height into account, and even the load itself, perhaps by watching hydraulic pressure when the loader is going up.

This is a complicated thing. For one thing it would have to be done with thorough understanding of the tractor's weight distribution. It's not something we could practically do ourselves. But if there are lawsuits out there, this might make huge economic sense for a manufacturer.

About 45 years ago I worked with some guys who designed systems with microprocessors in them. Microprocessors are common and cheap these days -- for example, they are the reason I can't understand the user interface on our goddam toaster. But back then, this was rare. These guys were working on a project to monitor the movement and forces on cranes, to prevent them tipping over. One situation they were working on concerns having the boom nearly vertical, lifting a load near the crane body, and then starting to lower the boom. It's very tricky, because stopping the boom will add tipping force from its inertia. An operator can start lowering the boom and put the crane in a condition where there is no way to avoid tipping a few seconds into the future, even though it is stable when the operator does this. If they could solve that problem back then, imagine what a manufacturer could do today.

I have never tipped. But I don't know if my worst near miss was 10% of the way to tipping, or 90%. Sure wish I knew.

What you say can be done, at a cost of several thousand dollars to the purchaser. Look what has happened to passenger cars.
Bring back common sense!

 

[WinterDeere]

What you say can be done, at a cost of several thousand dollars to the purchaser. Look what has happened to passenger cars.
Bring back common sense!

Development cost is likely close to $1M, amortized over the entire product line, plus $200k per year ongoing costs for development and maintenance of the product line. Actual hardware cost is going to be on the order of $10.

Over how many machines might that $1M initial + $200k per year be spread? If done by a third party and sold to several major manufacturers, the numbers might be sufficient to bring total added cost to the user down to something reasonable.

 

[dadohead]

The configuration and add-on's we put on our machines quickly complicates this concept: tires in/out? loaded tires? tire pressure? bucket size? ROP up/down? cab? on and on...

In the end, who will the lawyers go after if someone is hurt?: the manufacturer. Because of that, their direction will ALWAYS be to inform on safe practices but keep the ultimate responsibility with the operator.

 

[Shawn T. W.]

Then soon ... The tractors will be unable to be used ... Like the stupid crash avoidance system on my truck, SLAMS on the brakes when there is NOBODY, or a VEHICLE withing a quarter of mile, sometimes nothing in view! Wait until your tractor stops and/or turns away from a situation that some programer deems "unsafe"!

Yeah I know ... I'm told the radar just needs to be adjusted ... Had that done, still does it!

When one of these so called safety devices will take over control, because the programer thinks they know how to drive a truck or tractor, but probably never has been in one before ... They don't make the computer to "think" like a human it's just "X's" and "O'" and once something doesn't line up with the program, it just defaults to "PANIC" ...

I'd never buy a tractor that was programmed to be "smarter" than me ... If I want a robot tractor, I'd buy one, I'll only buy a tractor with a seat for me!

It takes a responsible and intelligent human to make "on the fly" decisions, who are willing to be held accountable for there actions ... Nobody is forcing me to drive near my creek, and if I roll my tractor down into it, I don't expect anyone to pay for my "mistake", and it's not gonna hurt anybody but me, I'm not "endangering" anybody else ... I've had enough with the nanny state dictates about what they say "is good/safe for you" !

 

[scootr]

Common sense and Personal responsibility are outdated ideas. It's the governments responsibility to ensure we are safe and fed.

 

[dadohead]

I don't buy this. After all, by choosing to not implement such systems, lawyers could go after manufacturers for not implementing reasonable technology that would allow one to better avoid rollovers.

Just illustrating their viewpoint.

Child backovers are the worst kind of accident. Usually, the root cause is that they had been given tractor rides by grandpa (teaching them "tractors are fun!") Later, they chase after the machine wanting a ride.

Sensor technology exists to equip that machine to warn the operator "something is behind". Making a smart tractor puts the responsibility on the  manufacturer. The solution we get is RIO (reverse implement option) the mower won't run in reverse unless the OPERATOR hopefully looks back and overrides the system allowing the PTO to continue running. Responsibily is now on the operator. Everybody HATES that solution but guess what?... the manufacturer never loses in court.

A tractor manufacture will fill the manual with best practices regarding rollover. They will avoid "smart tractor" solutions everytime.

 

[Jstpssng]

Common sense and Personal responsibility are outdated ideas. It's the governments responsibility to ensure we are safe and fed.

People likely have been saying this since the days of Caesar... and I don't mean the salad.

 

[RayIN]

This quote from Ronald Reagan sums this situation up nicely.
The nine most terrifying words in the English language are "I'm from the government, and I'm here to help."
Ronald Reagan