Lift capacity of 3-pt hitch question (plz keep it simple)

[LD1]

And height to capacity are proportional. Can be stated as a ratio or percentage.

I think I mentioned this earlier in this thread but it could have been in another.

Simplest way to calculate the 3ph capacity. If you know the spec for the ball ends all you need is a tale measure.

Measure how far the load moves for every inch the balls move. That's the same ratio capacity follows.

Ie: balls move 1", load moves 2", capacity will be 1/2.

Just as I state that the capacity changes with different toplink settings, so will the lift height.

 

[SPYDERLK]

The tractor is only part of what determines how true the parallelogram is.

Toplink length. Many different lengths sold. Some rea lly short, some really long.

Implement pin spacing between toplink and lower link. All of my stuff is old equipment. Nothing conforms to "standard" or is QH compatible. If the TL is spaced really high above the lower links on teh implement it wont lift as much, spacer closing is closer to parallel, and will lift more. I have about a dozen homemade implements, Root ripper, single shank ripper, multiple trailer movers, carry-alls, etc. Things like the 6' ripper, that sticks back pretty far like a rear blade (cause it rotates 180*), I make the toplink higher on the implement, so it lifts and rotates and gets it higher off the ground for clearance when crossing swales or uneven terrain.

When doing things like the trailer movers, I make the toplink much closer to the lower links. To Actually make it a PERFECT parallelogram. That way through out the entire lift range, the ball hitch remains at the same angle, and dont rotate around and mess up the trailer couplers.

From observation of the geometry on my Kub tractors and the Mahindra Ill predict that you have a decent chance of achieving a good // on the Kub vs almost none on the Mahindra. ... All my Kubs have the tractor 3pt pivots in a vertical plane, whereas the pivot points on lift vs top link on the MH are horizontally displaced by about a foot. This latter is a deficiency that is impossible to resolve in real life situations. -- The back of the tractor would have to set about 4feet higher than the front to bring the pivots into the vertical alignment of gravity; then, the //ogram of equal link length would function in the usable range instead of toggling overcenter at the very bottom of that range.

,,,,OTOH, On the Kub the only barrier to a very good //ogram is the [too small] vertical separation of the pivots. This would be easy to improve by a change on the implement or the tractor.

,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,AND

If feel like someone owes me an apology But seriously, there is no reason why the theoretical and the practical cannot be one in the same. And if you understand that, you can take an implement that may be just a little to heavy to lift and modify your geometry so that you can lift it - and that my friend is practical.

A recognition of the "theoretical"/factual Physics is needed to make the practical choices. Thats Progress.
,,,larry

 

[Everhard]

The original thread question:

If your 3-point hitch is rated to lift 1500 lbs, can you put on a 100 lb lift fork attachment and then lift a pallet weighing 1400 lbs? Not driving around, just simply lift a pallet of that weight?

Has anybody verified their tractor's maximum lift with a known weight? A pallet of landscape pavers, for example, you could count the pavers and know pretty accurate. Four 55gal drums of fuel is 1400 lbs. Understood that rarely do you actually know the real weight of a pallet.

3-point pallet fork example: View attachment 418435

So I had to go back to the beginning (having been following this whole thread with lots of amusement, thanks for that!) to remember what was the original question.

Sodo my answer to your above question would be you're right at the limit of what your tractor on paper will lift so that in itself tells you you may or may not be able to lift the load, BUT if you want to "help" your tractor and possibly guarantee that it will lift it then add a hydraulic top link which will allow you to adjust the length of the one "arm" and make the arms closer to //. (lol had to get those in there.) Joking apart though if your hydraulic toplink has enough length to allow it to become just marginally longer then the lower arms then effectively you'll be able to lift slightly more then the max your tractor can lift on paper keeping in mind doing so means:
1) it won't lift as high
2) the load will start to tilt down as you lift up - the longer the top link is vs the lower arms the more this effect will become pronounced.

Incidentally a hydraulic top link will make using a set of forks on the back of the tractor much more useful. (sidebar to the original question, sorry.)

Last thought: If the original question was asked because you're planning on doing said lifting all the time then I'd say go get a bigger tractor - being right at your limit every time you use the tractor will be frustrating and quickly grow old. If you asked this just to find out how close you can get to the tractor's theoretical limits then frankly while you're going to get (and have got) lots of friendly advise at the end of the day the only answer that's really going to satisfy is for you to test it out yourself, and then you'll know exactly what your limits are. If you find you cannot lift anywhere close to what the tractor "should" be able to lift then you probably need to adjust your relief valve. I'd expect a tractor to be able to lift pretty close to what the manufacturer advertises. That's been my experience to date.

E.

 

[teg]

...having been following this whole thread with lots of amusement, thanks for that...

Ditto... but I don't think this thread is HOW to actually lift 1500 #... IF it was, setting your hydraulic pressure above the max setting should do it.

I'm not sure if this thread is more about truth in advertizement or how the companies calculate capacity? Sounds like this was a spin-off from "...(Steel strength thread kinda got hijacked)..."

My guess is if a company says it can lift a certain weight, they better make sure it's able lift it with whatever geometry the tractor has...

 

[LD1]

The original thread question:



So I had to go back to the beginning (having been following this whole thread with lots of amusement, thanks for that!) to remember what was the original question.

Sodo my answer to your above question would be you're right at the limit of what your tractor on paper will lift so that in itself tells you you may or may not be able to lift the load, BUT if you want to "help" your tractor and possibly guarantee that it will lift it then add a hydraulic top link which will allow you to adjust the length of the one "arm" and make the arms closer to //. (lol had to get those in there.) Joking apart though if your hydraulic toplink has enough length to allow it to become just marginally longer then the lower arms then effectively you'll be able to lift slightly more then the max your tractor can lift on paper keeping in mind doing so means:
1) it won't lift as high
2) the load will start to tilt down as you lift up - the longer the top link is vs the lower arms the more this effect will become pronounced.

:thumbsup:

Wow, someone who actually understands how the hitch works, and just how dynamic it can be.

 

[LD1]

My guess is if a company says it can lift a certain weight, they better make sure it's able lift it with whatever geometry the tractor has...

While I dont know this to be factual, I would think this pretty spot on to how they are actually rated. (at least at the 24" back mark because no matter the geometry, the number at ball ends wont change.) I would say they use the OEM length toplink, in the bottom hole and as short as it will go, and thats the rating. (Which looses the most capacity at any point back).

Example, My 6' bushhog is ~1100# and lots closer to a 36-40" load center. My tractor is rated for 1496# at 24". It can lift the bushhog, even with a 200# person standing on it, in whatever configuration I want. With the TL in the bottom hole and short (to cause the tailwheel to raise high), I am sure the hydraulics dont have much left in them.

But I can come pretty close to actually making my hitch lift parallel with the bushhog by using the top hole and lengthening the TL a ways. In that configuration I would say I could lift a fair bit more than the 1496# spec, and have done so when using the flat deck of the bushhog like a carry-all moving odds and ends around, and mind you that is at more than 24" back

 

[4570Man]

The easiest and most accurate way to determine lift would be to get a boom pole and crane scale. Then chain it up and see how much it lifts.

 

[LD1]

The easiest and most accurate way to determine lift would be to get a boom pole and crane scale. Then chain it up and see how much it lifts.

Yep, that would be spot on accurate for that configuration.

To get a true understanding you would have to do as I suggested in post #55. Pick a hoe on the tractor side and make the TL as short as it will go. Then repeat with as long as it will go.

That will give you 2 readings. You can chart them two points out on a graph with one axis being lift height and one being top link length. Connect the dots, cause whatever the top link length is will be an almost perfect linear graph in relationship to lift capacity.

Can do that test for multiple points along the boom pole, and in all the available toplink mounting locations on the tractor. Now you will have a good idea what the max you can lift is and in what configuration the toplink needs to be in. These results and graphs will be the same for any implement that has the same TL spacing. If you have something that has toplink spacing different than the boom pole, then everything changes again.

You will also notice the direct (inverse proportional) relationship to how high the boom lifts vs hoe much it can lift.

 

[CDN Farm Boy]

:thumbsup:

Wow, someone who actually understands how the hitch works, and just how dynamic it can be.

I have no problems understanding how it works but please answer this: Just because the hitch CAN be dynamic, why does that mean that it HAS to be dynamic?

I am well aware that there is a whole pile of adjustment available and the height vs weight trade-off.....BUT if you don't adjust it, how is it still dynamic? Just pick a setting and leave it there.

I don't adjust mine for anything other than to get an implement to sit flat on the ground which isn't more than a turn or 2 of the top link (sure that makes a slight bit of a change but nothing compared to min length vs max length you guys are talking about). Lift arms stay in the same hole. Top link stays in the top hole. Everything I have runs on the QH so vertical separation at the attachment end stays consistent. For all intents and purposes, my hitch doesn't get adjusted. Is it still a dynamic hitch even though I NEVER make use of the adjustability of it?

Don't get me wrong, I'm not trying to pretend that there aren't reasons for using the available adjustability but I'm pretty sure I'm not the only one that isn't using it and has just set it and left it.

 

[Everhard]

CDN Farm Boy - agreed if you have a manual top-link you pretty much set it for the implement and forget it. It's not exactly something you want to be adjusting much as it's annoying to be jumping off and on the tractor all the time. If you get a hydraulic top-link you're getting it expressly for it's ability to change at any time to suit what you're doing. I personally got one for 3 different implements:
1: snowblower - great for setting how close the blower will blow snow off the ground.
2: blade - nice to be able to change the angle (but now I also want hydraulic adjust for the lift arm...)
3: Forks - makes using forks on the rear much more effective.
Actually I'll add a 4th: My custom made concrete barrel when I made it I didn't get the toplink attachment point in the right place and every time I use it I have to drastically change the length of the toplink vs my rear finishing mower - it was a pain in the *** but the hydraulic toplink makes it a non-issue. plus added bonus I've a hitch receiver on the concrete barrel so I can tilt it up and down to get a more optimum angle for the trailer when it's hooked onto the barrel.

I'm sure I'll find many more uses but there's a start to how useful having a toplink that can be adjusted on the fly. Totally worth the couple hundred $'s it cost. (Yep I'm lovin' that "upgrade".)

...And to bring it back into the conversation it can help the tractor lift to it's max. So hey, there's another bonus. (Obviously you can achieve this with a regular manual toplink but you'll be much happier just moving a lever from the saddle vs getting off and on...)

E.