Calculating FEL Lift Capacity

[LD1]

While we are on this subject. I am in the process of building a front end loader for a Deutz Allis 1920. I have the mounts done and the arms are more or less built (need to clean up the welds and weld cross bar in). I am planning on using 1.5" bore with 1" rod cylinders from SS, they have some specific for loader arms. I don't need to lift a ton but I would like to lift a minimum of 500 lbs. The lift cylinders will be around 25-30 deg. I guess my question is should I use the 1.5" cylinders or bump up to 2" cylinders? The calculation I posted yesterday above here has the 1.5 cyl at about 1700 lbs each and a 2" cylinder at about 2200 lbs each. I know there is more to the math and geometry than I am posting so if you need any more info just shout. I'm suing a pressure of 1500 psi.
Thanks in advance.

edit: Ok so going off of rock knocker's drawing is it safe for me to assume I can use the same formula? Overall distance from pivot to pin over distance of pivot to cyl mount?
I'll get some measurements and report back.

Yea, gotta know more about the geometry of the loader.

Tractors that use ~1.77 (45mm) cylinders are typically rated in the 1000# range....to full height.....at the center of the bucket.

Some can be more, some can be less, all just depends on loader geometry. Cylinder length also comes into play. Longer cylinders can use a more aggressive than short cylinders which loose some to angles.

Tractors that use ~2" cylinders (50mm) are typically in the 1500-2000# lift range.

But modern stuff is typically 2500PSI as well.

So we need to know for sure what the pressure is. Your assumption of 1500psi is not a good one. Assuming that may put you into larger cylinders to get what you want, but what if your pressure is indeed 2500psi? Now you can lift about twice what you designed for.....and maybe twice what the tractor is rated for.

 

[LD1]

I'm just a stupid geologist, so I may have made fundamental assumptions in my math using triangles, resultants and the like. I scaled off the drawing, rounded some numbers because this isn't a classroom test and figured the mechanical FEL assembly had no weight.

If I'm wrong, I accept that

I too am having a hard time figuring out what you are trying to solve for. And 17 degrees you used is an irrelevant number. The angle of the cylinder to the ground isnt what matters. ITs the angle of the cylinder in relation to what its pushing on....which he has listed at 29 degrees.

 

[gladehound]

Yea, gotta know more about the geometry of the loader.

Tractors that use ~1.77 (45mm) cylinders are typically rated in the 1000# range....to full height.....at the center of the bucket.

Some can be more, some can be less, all just depends on loader geometry. Cylinder length also comes into play. Longer cylinders can use a more aggressive than short cylinders which loose some to angles.

Tractors that use ~2" cylinders (50mm) are typically in the 1500-2000# lift range.

But modern stuff is typically 2500PSI as well.

So we need to know for sure what the pressure is. Your assumption of 1500psi is not a good one. Assuming that may put you into larger cylinders to get what you want, but what if your pressure is indeed 2500psi? Now you can lift about twice what you designed for.....and maybe twice what the tractor is rated for.

I didn't realize the 1500 psi was a guess. Yes, you need to know that number for sure!
Agree 45mm cylinders would probably fit the bill best. I had a loader with 45mm lift cylinders and it was rated at 850 pounds at full lift height (which was ~6.5ft if I remember correctly) That was at ~2000 psi. Keep in mind that 850 rating at the pins means less than that in the bucket.

Without doing math, there is a real risk that 1.5" will be too small and it is likely that 2" is overkill. 45mm is probably a good match but again, need the numbers I asked for before to do the math.

 

[Turbys_1700]

Kubota has a power position and a standard position listed on some of their loaders that give different lifting capacities. I don't think that is as much geometry related as it is height related. I placed 40 old cement blocks in my bucket back several months ago. I had an old building that had fallen down and wanted to see how well the loader handled them. I figure the blocks were over 50# each. These were formed back in the 50's and were concrete and very heavy. I calculated over 2,000# plus the bucket. The loader lifted them to full height at idle. The rated specs for the loader are 2200# at full height at 800mm from the bucket edge.

I've only owned two tractors with FEL's and both were able to lift a full bucket of gravel or dirt to full height. My smaller Stoll FC 350 on my New Holland 1720 was rated at around 1000# give or take and with the 1/3 cu yd. bucket that is in that range for gravel and sand. I remember running it into a load of sand and with a heaping bucket I would need to back it up to lift it. That load was rounded over the top. Never really got into the math of the loader capacities. On my New Holland the specs are given for max pressure of 19.8 MPa which equals 2872 psi.

 

[LD1]

Power position actually has to do with both lift height and geometry.

the greater the angle between the loader arm and cylinder....the more power it has for lifting that loader arm. Moving to power position increases the angle.

The lower lift height is just a result of this.

Look at the design in general.....of loaders of the past vs modern. In the past, lift cylinders had a VERY generous angle. The cylinder base was mounted several feet below the lift arm pivot, like at the bottom of the lift post. This made for a large angle and more power.....and to compensate for lift height, they had a very long stroke.

IT wasnt uncommon to see 30-36" stroke lift cylinders to get the hight needed, and for the base to be mounted low for power.

Modern loaders take a different approach. They use a much shorter cylinder, and a much smaller angle between the loader arm and cylinder. But make up for it with cylinder diameter.

Here is a few pictures from google that illustrate what I just said

 

[gladehound]

Power position actually has to do with both lift height and geometry.

the greater the angle between the loader arm and cylinder....the more power it has for lifting that loader arm. Moving to power position increases the angle.

The lower lift height is just a result of this.

Look at the design in general.....of loaders of the past vs modern. In the past, lift cylinders had a VERY generous angle. The cylinder base was mounted several feet below the lift arm pivot, like at the bottom of the lift post. This made for a large angle and more power.....and to compensate for lift height, they had a very long stroke.

IT wasnt uncommon to see 30-36" stroke lift cylinders to get the hight needed, and for the base to be mounted low for power.

Modern loaders take a different approach. They use a much shorter cylinder, and a much smaller angle between the loader arm and cylinder. But make up for it with cylinder diameter.

Here is a few pictures from google that illustrate what I just said

View attachment 490116View attachment 490117

Great illustration!

With the older design, you will generally have a much greater difference between lift capacity at low height vs full height because the angle of the cylinder to the loader arm changes more as you lift.

With the newer design, you have much closer breakout to full lift ratings.

For example, my Kioti LB1914, while not as extreme as your picture had wider angle between lift arm and cylinder than my current DS4510. The LB1914 has 2x the breakout compared to it's full height lift. The DS4510 has 1.34x more breakout compared to full height lift capacity. In a way, the older design favors breakout force while the newer design favors a more even lift cycle (and accommodates those nice big front tires! :thumbsup

 

[LD1]

Great illustration!

With the older design, you will generally have a much greater difference between lift capacity at low height vs full height because the angle of the cylinder to the loader arm changes more as you lift.

With the newer design, you have much closer breakout to full lift ratings.

For example, my Kioti LB1914, while not as extreme as your picture had wider angle between lift arm and cylinder than my current DS4510. The LB1914 has 2x the breakout compared to it's full height lift. The DS4510 has 1.34x more breakout compared to full height lift capacity. In a way, the older design favors breakout force while the newer design favors a more even lift cycle (and accommodates those nice big front tires! :thumbsup

Perhaps. Nevery really looked at how extreme the changes are from max height to breakout.

While the angle change may be greater I think one has to look at it like "percentage of angle change".

An old-school loader may go from 30 degree initial angle to a 15 degree max-height angle. A 15 degree change.

A new-school loader may start at 15.....and at max height only be down to 7.5 degrees. Only a 7.5 degree loss of angle vs the 15.

But as a percent, They both lost 50 percent of their initial angle. And thus, both will have lost 50% of their power. Without having dimensions of several different loaders, of each design, and plotting them out to see what they do....its hard to say.

One must also factor in lift height. The higher it lifts the more it changes. Take an old school loader with a steep 30 degree angle and 36" cylinder......might drop to the above mentioned 15 degree angle and give up 50% of its power, but be able to lift to 11' high. But a loader of similar design, us a 32" cylinder.....shift cylinder base mounting point a little forward to compensate for the shorter cylinder....and the loader may now only lift 10' high. But only drop to 20 degree angle.

Just too many designs and variables, I think, to say definitively that old-school looses more as the loader is raised.

 

[npalen]

Interesting stuff! Reminds me of the loaders built by Kent Mfg in Tipton, KS where I worked back in the 70's. I believe they were originally NuWay brand out of Barnard KS. Anyway, one of the options was a HiReach model which had greatly extended masts even more than those shown on the Ford that LD1 posted above. Don't remember the cylinder stroke but they were long!

I suspect that the modern "low profile" design" including curved lift arms has (have) a lot to do with aesthetics also. The extended masts were a bit unsightly.
I'm guessing that PSI also has a lot to do with todays compact/slick FEL appearance. The short coupled geometry makes use of much higher PSI than years ago where 1500 PSI might be considered average. It's really not much different than today's high output engines in a smaller package than years ago.

 

[LD1]

Interesting stuff! Reminds me of the loaders built by Kent Mfg in Tipton, KS where I worked back in the 70's. I believe they were originally NuWay brand out of Barnard KS. Anyway, one of the options was a HiReach model which had greatly extended masts even more than those shown on the Ford that LD1 posted above. Don't remember the cylinder stroke but they were long!

I suspect that the modern "low profile" design" including curved lift arms has (have) a lot to do with aesthetics also. The extended masts were a bit unsightly.
I'm guessing that PSI also has a lot to do with todays compact/slick FEL appearance. The short coupled geometry makes use of much higher PSI than years ago where 1500 PSI might be considered average. It's really not much different than today's high output engines in a smaller package than years ago.

Alot of the design of shorter masts has to do with quick attach loaders. Gotta be able to uncouple.....and then back out from under it and not rub the mast on the tire or front axle

 

[gladehound]

One must also factor in lift height. The higher it lifts the more it changes. Take an old school loader with a steep 30 degree angle and 36" cylinder......might drop to the above mentioned 15 degree angle and give up 50% of its power, but be able to lift to 11' high. But a loader of similar design, us a 32" cylinder.....shift cylinder base mounting point a little forward to compensate for the shorter cylinder....and the loader may now only lift 10' high. But only drop to 20 degree angle.

.

I think both may be at similar angle when at max lift. However, the loader with the much lower mount point directly below the loader arm pin will start with a much more open angle. And this is the basis of my theory about there being a bigger difference between breakout and full height lift (might not be the case if "full height" is not the same amount of rotation for each)

Hopefully somebody has the time to look up a bunch of examples. (however, I wonder if older tractor loaders before the days of SSQA are even rated at the pins or if they used some more realistic rating which could throw off any comparison?)

 

[PILOON]

Don't know all the math but my CUT will lift the rear clear of the ground when I have the bucket teeth jammed under a big rock or tree roots.
Tractor is 3000# plus loaded tired plus 300# rear weight so I presume loader is under 3000# range but close if I can flip the rock but not lift it.
How's that for critical math?
But I can always lift a full bucket of crushed stone or wet sand.

 

[JCByrd24]

A new-school loader may start at 15.....and at max height only be down to 7.5 degrees. Only a 7.5 degree loss of angle vs the 15.

But as a percent, They both lost 50 percent of their initial angle. And thus, both will have lost 50% of their power. Without having dimensions of several different loaders, of each design, and plotting them out to see what they do....its hard to say.

Mathematically your first statement that both lost 50% is not accurate, making your second statement very accurate. The nature of the trigonometry involved here is not linear and requires more math than comparing the percent change of angle, but you are on the right path comparing percent change, it is often more telling then raw numbers.

 

[LD1]

Mathematically your first statement that both lost 50% is not accurate, making your second statement very accurate. The nature of the trigonometry involved here is not linear and requires more math than comparing the percent change of angle, but you are on the right path comparing percent change, it is often more telling then raw numbers.

Splitting hairs at those angles.

Sin 30 = 0.5
sin 15 = .259
sin 7.5 = .131

Going from 30 to 15 .....you loose 48.2% of force. Going from 15 to 7.5, you loose 49.5 %

 

[davedj1]

Thanks for th e feedback. I had a very long day and can't wrap my head around this at the moment. I did look at a new 2501 I think it was Kubota today, the lift cylinders measured just a hair over 2" on the outside with the shaft measuring a hair over 1". That loader is only rated for like 800 lbs and the angle is fairly flat for the lift cylinders.

 

[npalen]

Anyone reading this thread will never look at a front end loader the same.:confused2:

 

[gladehound]

Thanks for th e feedback. I had a very long day and can't wrap my head around this at the moment. I did look at a new 2501 I think it was Kubota today, the lift cylinders measured just a hair over 2" on the outside with the shaft measuring a hair over 1". That loader is only rated for like 800 lbs and the angle is fairly flat for the lift cylinders.

I guess that's another way to go... just find a loader on a factory machine that does what you want and copy the geometry and cylinders. But then you still have to know your pressure. System pressure on that 2501 is around ~2,200 psi. If your system has and is designed for lower pressure, you may need bigger cylinders to do the same thing.

 

[gladehound]

If anyone wants another fun problem to work on... my KL402 loader on my Kioti DS4510HS has a roll back spec of 2990 pounds at 19.5" past the pin. I believe this is a mistake in the literature. This is about what my math works out to for one cylinder if you subtract a little for the bucket.

Here is some information to figure out the problem of how much roll back there actually is at a given point past the pins...

Bucket cylinder bore 2.16"
Bucket cylinder length 20.67"
loader relief pressure 2556 psi
Rod diameter 1.18"
Range of travel over full cylinder stroke 115 degrees
Number of cylinders = 2

The retract force of the cylinders combined should be 13,135 pounds (surface area cylinder ID minus surface area of rod multiplied by psi). Given cylinder length and degrees of travel it should have 136,166 inch pounds of torque, average, realizing that it wont be the same throughout range of travel based on geometry. At 19.5" getting 6,983 pound of roll back force average. Not even close to the 2990 pound spec at 19.5" at ground level.

The loader has an extra linkage like most modern loaders do and that makes the geometry a little more complicated. I realize that at ground level the loader curl is in the upper part of the range and therefore will be a little weaker. But going from ~7000 average (not peak) to ~3000 seems too extreme a difference.

This has me perplexed. I actually do have an 1,100 pound hanging scale coming in the mail next week. So I can weigh enough heavy stuff to actually do a real world test with measured weights.

But if anyone wants to take a crack at the math and tell me what I'm missing, I'm all ears.

 

[4570Man]

I think the extra linkage hurts you a lot at the upper end of the stroke. The rating is likely at the weakest part.

 

[npalen]

If anyone wants another fun problem to work on... my KL402 loader on my Kioti DS4510HS has a roll back spec of 2990 pounds at 19.5" past the pin. I believe this is a mistake in the literature. This is about what my math works out to for one cylinder if you subtract a little for the bucket.

Here is some information to figure out the problem of how much roll back there actually is at a given point past the pins...

Bucket cylinder bore 2.16"
Bucket cylinder length 20.67"
loader relief pressure 2556 psi
Rod diameter 1.18"
Range of travel over full cylinder stroke 115 degrees
Number of cylinders = 2

The retract force of the cylinders combined should be 13,135 pounds (surface area cylinder ID minus surface area of rod multiplied by psi). Given cylinder length and degrees of travel it should have 136,166 inch pounds of torque, average, realizing that it wont be the same throughout range of travel based on geometry. At 19.5" getting 6,983 pound of roll back force average. Not even close to the 2990 pound spec at 19.5" at ground level.

The loader has an extra linkage like most modern loaders do and that makes the geometry a little more complicated. I realize that at ground level the loader curl is in the upper part of the range and therefore will be a little weaker. But going from ~7000 average (not peak) to ~3000 seems too extreme a difference.

This has me perplexed. I actually do have an 1,100 pound hanging scale coming in the mail next week. So I can weigh enough heavy stuff to actually do a real world test with measured weights.

But if anyone wants to take a crack at the math and tell me what I'm missing, I'm all ears.

Can you show us the geometry of the compound linkage between bucket and cylinders? I would have thought that this linkage would tend to maintain a more consistent lever arm advantage thru the full motion. Is there another reason for the compound linkage?
We used that type of linkage extensively in farm tillage equipment design for folding wing sections to near 180 degrees.

 

[LD1]

If anyone wants another fun problem to work on... my KL402 loader on my Kioti DS4510HS has a roll back spec of 2990 pounds at 19.5" past the pin. I believe this is a mistake in the literature. This is about what my math works out to for one cylinder if you subtract a little for the bucket.

Here is some information to figure out the problem of how much roll back there actually is at a given point past the pins...

Bucket cylinder bore 2.16"
Bucket cylinder length 20.67"
loader relief pressure 2556 psi
Rod diameter 1.18"
Range of travel over full cylinder stroke 115 degrees
Number of cylinders = 2

The retract force of the cylinders combined should be 13,135 pounds (surface area cylinder ID minus surface area of rod multiplied by psi). Given cylinder length and degrees of travel it should have 136,166 inch pounds of torque, average, realizing that it wont be the same throughout range of travel based on geometry. At 19.5" getting 6,983 pound of roll back force average. Not even close to the 2990 pound spec at 19.5" at ground level.

The loader has an extra linkage like most modern loaders do and that makes the geometry a little more complicated. I realize that at ground level the loader curl is in the upper part of the range and therefore will be a little weaker. But going from ~7000 average (not peak) to ~3000 seems too extreme a difference.

This has me perplexed. I actually do have an 1,100 pound hanging scale coming in the mail next week. So I can weigh enough heavy stuff to actually do a real world test with measured weights.

But if anyone wants to take a crack at the math and tell me what I'm missing, I'm all ears.

As someone else said, that ~3000 is probably the minimum.

As to your extremely high number.....where did you get the 115 degrees from. I think that is a bit on the low side.

My LA844 loader has the same size cylinders. And they list 3 rollback measurements. 4400# at ground level, 4300# at 1500mm and 2800# at max height.

Not sure why that correlate the rollback with a lift height. I assume at each height, it is measured with the bucket bottom flat. So at the 3 different points, the bucket cylinders/linkages are extended more and more as the loader is raised.

Kubota also has a chart in the manual illustrating the curve. Fully dumped bucket is gonna be the weakest on rollback. The more it rolls back, the stronger it gets.....to a point. Then will start to get weaker again before being curled all the way. The strongest point is somewhere around bucket level on the ground. What is the distance between the bucket pins. (pin in loader arm to pin in 4-bar linkage that attaches to bucket.)