Cheap FEL cylinders keep bending

[npalen]

No we arent.

I am talking about the distance from where the cylinder hooks to the bucket in relation to the pivot.

Where the 4-bar link attaches to the bucket is ALOT closer to the bucket/boom pivot than the direct pin.

If the bucket was only dumped half way.....the direct pin would have alot greater mechanical advantage.

At full dump or full curl the 4-bar would have the advantage. The lines would cross somewhere in between. It becomes a very complex computation to calculate, because you are taking a linear force and trying to convert it to a rotational force.

Not dissimilar to a piston, rod, and crankshaft in the engine. If the crankshaft is at perfect 180 degrees....you could put as much force on the piston as you wanted and it wont move. IF the crank were at 90 degrees....a pound of force equals way more rotational force going into the crank than say a pound of force on the piston if the crank were at 20 degrees.

And the above is infinitely variable. FULL dump is gonna have a different equation/value than say 2 degrees less than full dump.

It becomes a very complex computation to calculate, because you are taking a linear force and trying to convert it to a rotational force.

Actually its just a matter of using the perpendicular distance from the line of force to the pivot pin. That times the force being applied computes to torque. (rotational force)

 

[LD1]

It becomes a very complex computation to calculate, because you are taking a linear force and trying to convert it to a rotational force.

Actually its just a matter of using the perpendicular distance from the line of force to the pivot pin. That times the force being applied computes to torque. (rotational force)

Yes it's simple at a fixed point.

The complexity is the whole thing is variable as it moves. As the bucket rotates....the forces change. There is no simple "x" number of pounds of force will buckle the rod.

That's why loader rollback force is plotted on a graph in most loader manuals. It's not as simple as a single number.

The amount of force at a bucket edge....required to buckle the cylinder, could also be plotted on a similar graph....IF one had all the details and measurements

 

[npalen]

Yes, I understand what you're saying and agree. I was talking about the force at any given point during the cycle as you mention. A graph is the way to show the forces throughout the stroke.

 

[ruffdog]

 

[JWR]

And I just noticed that the SSQA plate mating with the back of the bucket is not the same plate comparing direct pin versus pivot links. The pin plate with the holes is made differently and thus with different leverage. My OBTW mech advantage conclusion in post #115 was wrong.

 

[Cougsfan]

One thing has became clear to me after all the ranting and raving in this post; the next time I buy a tractor I am going to pay close attention to the design of the curl rams. In general the shorter they are, the larger in diameter they are, the less they are apt to bend. As I do a quick look I see significant variance in curl ram design from tractor to tractor.

I keep hearing "Do not back drag with the FEL!". I have been doing it for years, so drastically as doing it with my front tires lifted off the ground, and have never had a problem. Probably due to my dumb luck of having a decently designed ram setup on the curl.

 

[JWR]

One thing has became clear to me after all the ranting and raving in this post; the next time I buy a tractor I am going to pay close attention to the design of the curl rams. In general the shorter they are, the larger in diameter they are, the less they are apt to bend. As I do a quick look I see significant variance in curl ram design from tractor to tractor.

I keep hearing "Do not back drag with the FEL!". I have been doing it for years, so drastically as doing it with my front tires lifted off the ground, and have never had a problem. Probably due to my dumb luck of having a decently designed ram setup on the curl.

We all have. The official position from dealers for years was "don't do it" but it was tongue in cheek because they ALL knew most people were doing it. The post above from ruffdog shows that Messicks (one of the more prominent Kubota dealers/sellers) not only buys into the reality of it being done they coach you in that video how best to do it.

My lesson was learned a few years back doing probably about the worst possible case of back dragging using a large MF tractor. I was preparing a site for a pole barn and some of the ground was hard baked clay soil approximately the same as rock. I pointed the bucket tip (not a std bucket but a 1000 lb 4-in-1 heavy bucket) into the hard ground, lifted the front of the tractor with it and backed up in 4WD at max power, low range, low gear. It worked for most of the job UNTIL all hell broke loose. A steel section of hydraulic line burst wide open, separated itself from the loader frame and spewed oil all over the place. OK, so I replaced the section of steel line and finished the job with newly found knowledge. BUT, the loader, the cylinders and everything else held up just fine. The weak link (aside from my brain) was the steel hydraulic line. My DL250 loader passed the test. I still wish I had the next heavier DL260 loader for unrelated reasons.

 

[ning]

I pointed the bucket tip (not a std bucket but a 1000 lb 4-in-1 heavy bucket) into the hard ground, lifted the front of the tractor with it and backed up in 4WD at max power, low range, low gear. It worked for most of the job UNTIL all hell broke loose. A steel section of hydraulic line burst wide open

Is the idea here that the back dragging made dynamic shock waves in the hydraulic line that went over its psi rating?
I'm thinking there was a fault there ready to go, and it would've happened soon enough even without the back dragging.

 

[ptsg]

Work port relief valves could easily solve all of this damage caused by back-dragging or the use of oversized implements.

 

[4570Man]

I keep hearing "Do not back drag with the FEL!". I have been doing it for years, so drastically as doing it with my front tires lifted off the ground, and have never had a problem. Probably due to my dumb luck of having a decently designed ram setup on the curl.

They’ll survive back dragging with the bucket at 45 degrees. It’s when you roll it to 90 degrees that problems happen.

 

[ruffdog]

The point made by the Messicks video is don't back drag with the curl cylinders fully extended. Same as what some of us has been saying. If you have the cylinder only half extended, then the overlap between cylinder barrel/rod/piston is much more and will keep the cylinder straight.

 

[AchingBack]

One thing has became clear to me after all the ranting and raving in this post; the next time I buy a tractor I am going to pay close attention to the design of the curl rams. In general the shorter they are, the larger in diameter they are, the less they are apt to bend. As I do a quick look I see significant variance in curl ram design from tractor to tractor.

I keep hearing "Do not back drag with the FEL!". I have been doing it for years, so drastically as doing it with my front tires lifted off the ground, and have never had a problem. Probably due to my dumb luck of having a decently designed ram setup on the curl.

The critical factor is the angle of the bucket when back dragging. My loader manufacturer, KMW, states: maximum angle of 15 degrees. I've never understood why people back drag with the wheels off the ground.

 

[Cougsfan]

The critical factor is the angle of the bucket when back dragging. My loader manufacturer, KMW, states: maximum angle of 15 degrees. I've never understood why people back drag with the wheels off the ground.

I do it with the wheels off the ground when I want to maximize compaction of the soil I am leveling. It definitely helps. I don't probably ever use much more of angle of 15 degrees when back dragging. If I want to cut into the dirt (which the steep angle would do) I either use the FEL going forward or a box blade.

 

[not2old]

I've been back dragging on my GC lots since I got it. I'm very careful when going forward and never go too fast in case I hit something solid. I've hit things solid enough to stall the motor two or three times but did no damage. Going backwards I've put the cutting edge vertical all the time. There are times the tractor doesn't have the power to move and I give it all it's got and wiggle the curl to get it started. Either the hydraulics are very well designed or I've been very lucky. After reading this thread I'll treat my machine with a little more respect.

 

[lpakiz]

A technique I use is to back drag with the HEEL of the bucket. You can see exactly how much material is either accumulating or disappearing. I use the nose of the bucket as a depth gauge, to regulate how aggressive the heel cuts.
When you get to the end of the stretch, lift the bucket and keep backing up until any leftovers are in front of the bucket. Then, don’t change the angle much, just so the cutting edge doesn’t penetrate, and drive forward, scrubbing the material under the bottom of the bucket. Usually, the front wheels are off the ground in both directions.

 

[4570Man]

The critical factor is the angle of the bucket when back dragging. My loader manufacturer, KMW, states: maximum angle of 15 degrees. I've never understood why people back drag with the wheels off the ground.

I’m sure they’re going or recommend a low angle or no angle but realistically it’s ok up to 45 degrees.

 

[JWR]

Is the idea here that the back dragging made dynamic shock waves in the hydraulic line that went over its psi rating?
I'm thinking there was a fault there ready to go, and it would've happened soon enough even without the back dragging.

No, I don't think so. Fault was me, not the equipment. At least in my case it didn't involve anything as complex as dynamic shock waves in anything. It was me operating the tractor such that I put terrific downward force into hard clay with bucket and then dragged the bucket tip in reverse as hard as I could. The mechanics of that are lengthy to describe in words but look at any bucket/loader photo and you can see that when the bucket is tip down vertically and you back up while shoving it into the ground you produce force compressing the bucket cylinders toward retraction. Not powered by the hydraulics at all, but powered by the force on the bucket through the connections to the cylinders. Such force against the cylinders is not limited by hydraulic pumps and thus not subject to safe pressure level protections. That's what people are talking about in concerns about back dragging.

 

[AchingBack]

To increase compaction, one thing you can do when back dragging is have a load of material in the bucket.

 

[rScotty]

I’m sure they’re going or recommend a low angle or no angle but realistically it’s ok up to 45 degrees.

I'd agree with that. We all like to keep the angle less, but it varies with the job. You definitely don't want to have so much angle it catches when backdragging.

Someone mentioned using the back of the bucket instead of the lip. That depends on the bucket shape, but it's a nice technique if the bucket is shaped right. I've always wondered about making up something so that the back of the bucket would work even better for back dragging and compacting. Then the front edge would just be a final smoothing.

I use the wheel brakes a lot when backdragging & bet others do too. I usually try to keep the front tires just barely touching the ground, but don't care if they rise up clear off the ground.
rScotty

 

[hornett22]

Those stump buckets always looked like a recipe for disaster to me.