Cheap FEL cylinders keep bending

   / Cheap FEL cylinders keep bending #141  

npalen

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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)
 
   / Cheap FEL cylinders keep bending #142  

LD1

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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
 
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   / Cheap FEL cylinders keep bending #143  

npalen

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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.
 
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   / Cheap FEL cylinders keep bending #145  

JWR

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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.
 
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   / Cheap FEL cylinders keep bending #146  

Cougsfan

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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.
 
   / Cheap FEL cylinders keep bending #147  

JWR

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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.
 
   / Cheap FEL cylinders keep bending #148  

ning

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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.
 
   / Cheap FEL cylinders keep bending #149  

ptsg

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Work port relief valves could easily solve all of this damage caused by back-dragging or the use of oversized implements.
 
   / Cheap FEL cylinders keep bending #150  

4570Man

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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.
 
 
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