3-point attachement point dimensions.

[Dan69GTX]

Does anyone have the correct dimensions for the connections (links) for building a 3-point attachment? If the dimensions for the attachment points are correct, then when you raise and lower a device it will stay level.

I've done this before using a level, and plumb bob and a lot of adjustmemt, but just thought someone would know it off hand.

Thanks!
Dan

 

[kennyd]

This was just answered in THIS thread.

 

[jmc]

I think to raise an implement while keeping it level, you need the 3ph linkage to form a parallelogram when viewed from the side of the tractor. The top link and bottom link(s) will need to be the same length-those correspond to the horizontal sides of the parallelogram. Also the distance from the top and bottom attachment points on the implement need to match the distance between the tractor's top and bottom attachment points. These two lengths are the more or less vertical sides of the parallelogram.

I think that 3ph linkages are designed to AVOID lifting parallel in order to lift the rear of the implement as much as possible.

Note that since the tractor's top attachment point is farther back than the tractor's lower attachment point, you will have the same arrangement on your implement.

John

 

[Dan69GTX]

Kennyd - thanks for the link to the other thread which you posted a link to the LSU ag site.

jmc - I agree that its got for form some sort of parallelogram. I was hoping someone would know any of the specs so I don't have to do the trial and error again.

I've built a 3pt trailer hitch before and made that so it wouldn't tilt when raising/lowering and I'd like to do the same for a carry-all. Unfortunately I can't measure the trailer hitch attachment points.

Dan

 

[jmc]

Unfortunately I can't measure the trailer hitch attachment points.

Dan

Dan,

You don't have to. Just measure the distance between the top and bottom link attachment points on your TRACTOR and use that distance for your implement. Once you adjust the top link length to match the bottom link length, the linkage can't help but be a parallelogram when you assemble it.

Not to complicate this but the A-frame on your implement will not be vertical unless your top link attachment point is behind the A-frame. (to duplicate the tractor geometry) No big deal unless you made your forks perpendicular to the A-frame beforehand)

If you make a scale 2D model of your links out of index card stock and pin them together with thumbtacks at the joints, you can articulate the assembly to test it. In fact, you can bastardize the top link attachment position on your implement, for example, to see if it tracks parallel enough for your purpose.

John

 

[mykleh]

Sorry to bring an old thread to life but I checked the LSU site and understand the "standards" but the 3pt standard is to NOT lift level which is my goal. in the previous post it mentions creating a parallelogram I have attached a picture of my tractor and now need to understand what to measure to create my parallelogram... Am i to work with the lower two red arrows? which amount to where the 3pt lift arms connect to the tractor and the upper lift link? I assume the actual lift arm (top red arrow) is irrelevant? your help as usual is appreciated!!

 

[Dan69GTX]

Yes, the top arrow is not useful - but it does look pretty.

The distance I used was about 14" up from the lower lift bracket to attach my upper link arm. For my tractor (kubota 3130) it allows the 3pt to lift evenly. You will have to check with your tractor if that distance will work - probably will, but I will not guarantee it.

Dan

 

[LD1]

You need to measure the distance between your two lower red arrows...The distance between where the lower arms connect to the tractor and where the top link hooks to the tractor.

Some tractors, and it appears yours does, have different places to hook the top link up. You will need to measure to the one you will be using.

Then use that measurement when you make your attachment. The top link point of the attachment should be the same distance above your bottom link point on the attachment as the tractor.

This will make the top link parallel with the bottom link which will result in it lifting level.

Sorry for the crude diagram but the distance of A should be the same as B if you want the attachment to lift level. If B is greater than A, the tail of the implement will raise higher when 3ph is raised and vice versa

 

[mykleh]

Thanks LD1! I thought that's what I wanted but it seems confusing when standing in the back of the tractor. Any great ideas how to measure those points as you know the lower set is under the tractor and wider then the center. I was contemplating putting a level on the 3pt arms adjust till level, put a steel square from level & measure from there up. or am I just complicating this and should just measure from the ground up? then the front to back measurement is not straightforward at all to discover.

 

[LD1]

I have always measured from the ground up to the top link and then the ground up to the lower arms. Subtract the lower arm measurement from the top and you got it.

The level idea would work to. It doesn't have to be exact to the thousandth of an inch. if you are a full inch off you won't notice much difference at all. Just get it as close as you can and you'll be fine

 

[jenkinsph]

Measure the vertical distance between the lower and upper link as mentioned gets you close.

To ge it to track level from the ground to the fully raised position you need the top link arm to be the same length as the lower arms.

Depending on the implement this may not allow enough ground clearance if you have to traverse hills or terrace rows.


Steve

 

[LD1]

Measure the vertical distance between the lower and upper link as mentioned gets you close.

To ge it to track level from the ground to the fully raised position you need the top link arm to be the same length as the lower arms.

Depending on the implement this may not allow enough ground clearance if you have to traverse hills or terrace rows.


Steve

Yot are right...To track level with the ground.

But it don't matter how short the top link is, it will remain at the same angle throughout the raise...ie if the top link is shorter, the tail will be higher than the front when on the ground, say 10 degrees, when you go to full raise, it will still be 10 degrees.

On a side note, most top-links that I have seen will adjust far enough to be the same length as the lower arms. One exception to this that I have seen is on my dads JD 2040. It is cat 2 but the top link pin sizes are cat 1. It has really long lower arms so we compensated by angling the vertical peice that hooks to the top link, to keep the hitch level and raise level. See diagram

 

[jenkinsph]

Yot are right...To track level with the ground.

But it don't matter how short the top link is, it will remain at the same angle throughout the raise...ie if the top link is shorter, the tail will be higher than the front when on the ground, say 10 degrees, when you go to full raise, it will still be 10 degrees.

On a side note, most top-links that I have seen will adjust far enough to be the same length as the lower arms. One exception to this that I have seen is on my dads JD 2040. It is cat 2 but the top link pin sizes are cat 1. It has really long lower arms so we compensated by angling the vertical peice that hooks to the top link, to keep the hitch level and raise level. See diagram

Hard to make this work when the top link and bottom links have different radius.


Hey the 2040 is a nice tractor with a good design.



Steve

 

[LD1]

You are absolutly right. I don't know what I was thinking when I said that. However the change of angle is minimal as compaired to the top link and bottom arms having different angles and not being parallel.

An example: Bottom arms 24" top arm 18" and parallel 12" apart results in only a 10 degree change over a 45degree raise. Whereas top link being 24" as well but 12" apart at the trator and 18" at implement (off parallel at the implement by 6") would result in a 22.5 degree change.

But what I can tell you is on the 2040 the top link is shorter than the lower arms, but they are parallel. Going from full down to all the way raised, the hitch ball's angle change is not noticable.

There is nothing to worry about when dealing with cat 1 becaust the top link can adjust long enough to be the same length as the lower arms.