Go BottomMaxed out 3ph pallet forks
 | Sparky
Join Date: Jun 2004 Posts: 0 Florida 
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2001-11-25 33415
What does it mean when a spec sheet says that a 3ph lift capacity is measured at 24" behind link ends? What are the link
ends? I have a pallet fork made by Rankin, and it mounts on a 3ph. It looks like a set of forks you would see on a forklift.
I tried to see how many blocks my JD 4400 could lift. It will lift 32 60# blocks about half way, not all the way up though. That figures
out to 1920 lbs, plus the forks, about 125 lbs, and the oak pallet, about 40?lbs. Estimated total approximately 2085 lbs.
My owners manual says 2200 lbs is the rated lift capacity. So, where is that magic center point? And who is Rankin? Can't find
them anywhere on the web?
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| TomG
Join Date: Feb 2002 Posts: 5406 Upper Ottawa Valley 
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2001-11-26 33417
The rating is 24" behind the lower link pins and can be interpreted as the centre of weight distribution. For blocks evenly distributed across a 4' pallet and forks, the centre would be 2' from the back of the forks minus the distance between the forks and link pins (not considering the fork weight). I can't exclude the fork weight in my estimations, because they weigh about 600 lbs. They have their own lift and tilt hydraulics that will lift more than the 3ph will, and I have to be very careful with front ballast. Many 3ph's will lift more than their rating but with less safety. Factors like tractor weight distribution and wheelbase are considered. However, I believe my Ford 1710 3ph works similar to what you describe. When I total up weights and distances, it lifts it's rating and no more. Even then it slowly and at pto rpm. Fortunately the 3ph supports more than it lifts, and the forks hydraulics give me good lift and speed.
I guess the reason for the rating definition is that 2' is a typical distance for the centre of an implement mounted on a 3ph. Sorry I can't help much about Rankin. I vaguely remember seeing the name recently and maybe not in relation to equipment. Good chance that what I recall would be a Canadian company.
....
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 | Art White
Join Date: Jan 2000 Posts: 6898 Waterville New York
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2001-11-26 33429
The 2' is used as a reference point. Nearly all three ponit hitch attachments are different sizes and it would be so hard to include all applications on a piece of literature. ....
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 | Murf
Join Date: Dec 1999 Posts: 7249 Toronto Area, Ontario, Canada
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2001-11-27 33460
The other variable in the process is the hydraulic systems pressure release valve, a variance on the setting will determine the ultimate lift capabilities. I'm not sure where you would find the release valve on your machine, if you have a manual it should tell you. It is traditionally set at the factory (or at the dealer during PDI sometimes) then rarely touched again. I have noticed quite a variance between the same make and model, but different units in our fleet. Best of luck. ....
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 | BillMullens
Join Date: Jun 2000 Posts: 649 Central West Virginia 
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2001-11-28 33486
I'd never heard of Rankin, but a Google search for 'rankin equipment' returned this link. Unfortunately, it didn't work when I tried it. Perhaps their server is down at the moment, may be worth a try later.
Bill Mullens ....
Link: Non-working Rankin link
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| Roger L.
Join Date: Jun 1999 Posts: 0
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2001-11-28 33487
Sparky, the "links" are the lower lift arms of the 3pt hitch. They are the two arms that have the swiveling balls in them that you put the pins through when you hook up an implement. The "link ends" refers to those swiveling balls.
Three point lift capacity is calculated as lifting torque, which is a force times a distance. So if you want to specify a one, you have to specify the other as well. The association of ag engineers specified "two feet behind the link ends" as the distance that represents the center of gravity of a typical implement. If your implement has the CG closer to the link ends then you can lift more; and vice versa.
Tractor manufacturers are not absolutely required to use that definition of 3pt lift capacity in their product literature, and in the 1970s and 80s there were several that did not. They reported the lift capactiy "at the 3pt ends", or in one case even farther forward!....which led to a lot of confusion when some 3pts seemed to be much more powerful than others. We see the same situation right now in loader and backhoe specifications because there isn't a universally accepted standard.
It is a simple matter for a manufacturer to make a 3pt that is tremendously powerful, but there isn't much point in making a three point hitch strong enough so that it will make the front wheels come off of the ground. ....
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