Position Control

[Anonymous Poster]

I'm buying a new 27/2910 and note that they have "position control" as a standard feature. Can anyone explain what that is?

Thanks

 

[Bird]

Kevin, this has been discussed a lot of times, but it may be easier to do it again than to find the old threads, perhaps by examples.

Position Control: On the B2710 (and lots of other tractors) the slot for the 3-point hitch lever is marked from 1 at the front of the slot to 8 at the rear of the slot. Wherever you put the lever, it stays there; all the way forward and the 3-point hitch is all the way down, all the way back and the hitch is all the way up; stop in the middle and the hitch lowers (or raises) to the middle and stays there.

No Position Control: The B7100 (and others) slot for the lever was not marked and the lever was in the center no matter what height the 3-point hitch was. Push forward on the lever and hitch starts lowering and continues to lower until the lever is returned to center at which point the hitch stops moving. Pull the lever back from center and the hitch raises and continues to raise until the lever is centered again. The distance forward or backward that you move the lever can change the speed with which the hitch raises or lowers (as does the engine rpm), but you have to simply look back at the hitch to tell whether it's the height you want, and move the lever back to center when it is.

Position control makes small adjustments in the hitch height much easier to do more precisely. You can also find the height you want, raise an implement (for instance at the end of a row to turn), then lower it back to exactly the same level by returning the lever to the same position.

Bird

 

[Harv]

Bird sez it like it is, but I would also point out that position control sets the minimum height from which the implement then "floats". In other words, there is no down force, and the 3-pt always floats.

I might be stating the obvious to some here, but it took me a while to realize how it worked in the beginning, so I just thought I'd share. /w3tcompact/icons/crazy.gif

 

[Sailorcrew]

Can you go into that a little more? I thought that there was down pressure always on the 3 point. Where is there no down pressure? At some point on the scale? I've only used a subsoiler that needed down pressure and had good results but wonder what I'm missing. I was just starting to think about a post hole digger and now am wondering if there's more to consider. Thanks, David

 

[Bird]

David, there are some post hole diggers that come with a "downforce" kit, but most do not. There are also some (but few) tractors that have down force on the 3-point. Normally, the only thing that exerts any downward force on the 3-point is the weight of whatever implement you have on (or just the weight of the lift arms themselves). Once an implement contacts the ground, it may exert additional down force. For instance, a post hole digger is an auger and it may screw itself into the ground (in fact, to the point that you have trouble getting it out), thereby pulling down on the 3-point (and then in hard ground, with dull bits, etc. you may have to add weight to it to get it to go down at all). With plows and subsoiler, the point enters the ground at an angle that tends to pull it down as the tractor moves forward, but the 3-point hitch doesn't push it down.

You can prove this to yourself quite easily. With no implement on the 3-point, raise or lower it to some point in the middle; neither all the way up or down. Then try to push down on it manually (won't go), but lift up on the arms and you can raise them manually, and when you turn them loose, they fall back to the same height you started with.

Bird

 

[Sailorcrew]

Bird, thanks. I now understand the 3pt operation. Like you said, when using the subsoiler, the angle of the blade is what pulled it into the ground. When hitting an object, it would ride up over it because there was nothing keeping it down. So, the 3 pt lifts only. Anything going downward is by the weight of the implement only. I was told (more than once) that the only dumb questions are the ones you don't ask. I'm more than willing to ask those questions. By the way, I found this explanation you gave, Bird, as clear and helpfull as your explanation on the hydrostatic pedal operation which had always caused my some confusion until I read your posts. Thanks again, David