![]() you can freely move them up to max travel. If you doubt this, wal up behind a ford or fergy and ask the owner to rais the lift mid way, now grab the lift arms. Therefor if you set the lowest leverl you want your mower deck to be at, either with the position control, or by a limit chain, the mower deck is actually free to 'lift' on its own, as in -float- to follow the contour of the terain. 2 different scenerios, both with different directions of forces on the geometry.įord and ferguson system lifts on most tractors do not incorporate ground down pressure. What you are thinking of is the analogy where a plow strikes a root or rock, and begins traveling under it, putting negative tension on the toplink, thus the lift would then try to extract the plow out of the ground. this will put the toplink in compression, and actually -lower- the lift. In the case of a 3pt mower, if the front of the mower strikes an object that won't move, the tail of the mower is going to try to flip up and rotate around the 2 lower lift points. for the draft sensing mechanism on a ford ( or any ferguson system tractor ) to operate, there must be negative compression on the toplink for it to activate the lift. ( this way, if you hit a stump or other object, the bushhog will pick up automatically ) the draft mechanism would interpret this as higher draft, and would lift the 3pt, and you would be mowing with a mower on the back that was bobbing up and down. In draft control, say you went over a rise, then there would be more weight on the toplink. it functions like plain old position control. Most notably, one of the older ones was called 'the fergy positioner' A fellow retired ford tractor mechanic I know also makes and sells a device called a 'zane thang' Both of these devices bolt onto the lift housing and allow for extra external feedback so that the draft mechanism is automatically counter-adjusted so that it in effect. Also, there were many add-on position control 'jigs' that will allow a draft only tractor using the ferguson system to function like it had position control. A flexible toplink connection that adds a few inches of play is now included with most rotary cutters, so that the front of the mower can pivot a bit when the tractor is on uneven ground. ![]() yet you can manually raise it with the 3pt lift to clear obstacles, then set it back down and know that you are mowing at the same height. that way you can mow without the mower dropping lower. you adjust the chain so that the mower is suspended at the level you want to cut at. Invariably they get a set of limit chains that attach at the toplink, and then run down to the implement pins. Anyone who has ever owned a ford 9n or 2n, or ferguson tX-20 can sure tell you that it is no fun to mow in draft control. ( Also DO use the draft control and NOT the position )ĭraft control is almost exclusively for ground engaging implements. heavy loads are best placed on the lower hole for the 8n. ( I would suggest one of the middle positions ) In that example, the lowest hole would be the highest mechanical advantage, and the highest hole would be the least mechanical advantage. Later ford designs like on their larger 5xxx and 7xxx tractors went to a toplink rocker that was connected and rotated on a pin at the top of the rocker, and then midway -down- the rocker was the draft plunger. Putting a heavy load like a 500-600 pound mower up in the top hole can actually damage the sensitive draft linkages under the lift cover by putting too much stress and range of motion on them. These holes are for implements with very light draft, like a spring tooth harrow or small cultivator, that have such low draft, that you have to mechanically amplify it ( with a lever ) so that the draft sensing lift can be adjusted. the upper holes are higher up than the draft plunger, and thus offer the most mechanical advantage ont he plunger. on the front side are 1 or more holes for the toplink. this plunger is connected to the draft mechanism linkages under the hyd top cover. midway up the rocker, in the back of it, it is coupled to a draft plunger and spring. on an N, the bottom of the rocker is mounted and can rotate on a pin at the base of the rocker. What hole to use is based on where the toplink rocker pivots, and where the draft sensing mechanism is getting its feedback from, in relation to the pivot, and the toplink connection. That's like saying some cars use gas, when someone writes in and ask what fuel to put in their car. Your comment is so vauge as to be totally useless. Toplink rockers are mechanical force amplifiers for feedback to the draft sensing mechanism. ( but on some tractors, the manual specifies to not use the bottom-most position )
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