grade school levers and fulcrums or rather a kids playground tetter totter.
hook low up low, and in center, below the axle. "swinging draw bar" some manufactures / dealers may skimp out on the actual swinging draw bar. the bar itself, and/or possible frame work that is needed to attach the swinging draw bar.
a 3pt hitch is good at pulling / dragging stuff. BUT, it is only good at pulling straight (driving forward), go into a turn, and you can easily twist the 3pt hitch linkages up (bend them and like). granted a 3pt hitch is rather rugged, and can take some abuse. other words if you have anything ground engaging (tiller, box blade, rear blade, disc, etc..., etc...) you generally want to raise the stuff up and out of the ground before taking a turn. more so a sharper turn.
another thing about 3pt hitch, is they are kinda in "auto float all the time" meaning if you started going up a hill, or rear tires go down into a hole or like. the 3pt hitch will raise up on you. this shifting the weight / load and were the pulling point is. causing a higher risk of flipping the tractor back onto itself.
i have seen it many times, and have come close myself, of flipping tractor back onto itself. it doesn't take much. one good sudden bite of traction and BAM! this is with either weights on front and/or having FEL (front loader) on. the tractor still has enough power to do a wheelie and keep on going backwards.
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one thing i like about the old allis chalmers CA tractor (1954) i have, with snap coupler vs 3pt hitch system. there is a spot underneath in front of the rear tires. were i can hook stuff up to. this location causes the front end to want to come down into the ground for kinda of a traction control vs the front end wanting to do a wheelie like on 3pt hitch tractors.
and in above, a swinging draw bar for a 3pt hitch tractor. hooks up in near location like the old allis chalmers i have. it is underneath the axle, and also more in front of the axle "hopefully" so as you are driving along. the weight of what ever you are pulling can be some what placed on the front tires. (though most tractors i have seen that is an extreme stretch of wording)