Lift Quadrant (Quadrant Lever)
The control lever arrangement moving over a sprung quadrant beside the seat; every angle of the lever matches a linkage position and the end is not used.
The lift quadrant is the control lever arrangement beside the tractor seat that moves over a quadrant made of spring steel. Every angle of the lever on the quadrant corresponds to a particular linkage position: at one end the arms go fully down, brought towards the middle sector they rise, and in the bend sector the transport position is found. The end of the quadrant is the continuous pumping sector and is not used.
The quadrant is read like a scale
| Sector of the lever | Behaviour of the linkage | What it means in the field |
|---|---|---|
| The lower end of the quadrant | The arms go fully down | Setting the implement on the soil |
| The middle sector | The linkage rises and stops at that height | Finding the working height |
| The bend sector | Transport position | Turning at the headland, travelling on the road |
| The end of the quadrant | Continuous pumping | Not used |
The quadrant is a mechanical reference scale. By bringing the lever to the same notch the operator finds the same working height again; that is why putting a mark on the quadrant is a widespread habit in the field. Leaving the lever forgotten at the end of the quadrant, on the other hand, makes the pump work for nothing and heats the oil; the damage done by the continuous pumping sector is explained under a separate heading.
The most misunderstood part of the quadrant is the bend sector. It does not take the linkage to its highest point; it gives, repeatably, a height at which the implement is clear of the ground and which is enough for transport. Taking the lever to the same point every time at the headland makes the implement rise to the same height on every turn — that is what the quadrant really gains you.
The mechanical adjustments on the quadrant
The quadrant itself is not a part that gets adjusted, but there are two adjustments on it: the tension of the spring and the friction of the lever. Both change over time and both must be settled before the electronic conversion.
- The tension of the quadrant spring keeps the lever from sliding on its own; if it has slackened the lever shifts during work.
- On most tractors the friction adjustment of the lever is made with a nut.
- The distances on the quadrant are not linear; a small angle can produce a large difference in height.
- If the lever slides on its own, this adjustment has to be put right before the electronic conversion.
How the electronic conversion relates to the quadrant
This is the range of movement that the electronic retrofit kits take as their reference. The LFT20 and the LFT54 move the lever within the usable range by pulling the quick lift cable of the quadrant system; the stroke is 60 mm on the LFT20 and 50 mm on the LFT54. The kit does not remove the quadrant and does not take over the function of the quadrant either — it only pulls the Lift-O-Matik cable, and when it lets go the lever returns with its own spring. What the stroke value means in practice is explained under the heading cable pull distance.
The tractors on which these kits are not fitted
If your tractor has no quadrant and cable arrangement, these kits cannot be fitted. On systems where the lever is connected straight to the valve spool and there is no cable, there is no cable to pull. On tractors that have a quadrant but whose cable has broken or been removed, the mechanical arrangement has to be completed first. How to tell whether your tractor is suitable is explained under a separate heading.
On tractors that have a quadrant but whose lever is either too stiff or too slack, a mechanical correction is needed before fitting as well. A lever that is too stiff strains the cable more than it should; a lever that is too slack does not stay at the point the electronic control brings it to and shifts during work. In both cases the trouble shows up in the kit but its source is in the quadrant.
Before starting on the kit, run the quadrant through by hand from one end to the other: the lever must move without catching, must stay where you leave it, and the cable must move together with the lever. Fitting carried out without passing these three checks cannot be put right afterwards with an electronic adjustment. See as well that the linkage gives the expected behaviour in every sector of the lever; a linkage that does not rise in the bend sector will not rise after the kit has been fitted either.
The context in which this term is used: Converting a tractor hydraulic lever to electronic control