Hy-tec Hydraulics actuating link pivots about PC roller assy (2) and moves back towards rockshaft. This allows spool (10) to come out under the action of spring main valve (38). This allow the oil to return from lift cylinder and discharge to the reservoir causing the lift arms and implement to lower under their own weight.
spring thus move the spool control valve plunger. As the spool plunger moves inward. The pilot port sleeve is uncovered, the consequent pressure drop allow the regulator ball to sear and pressure is directed to the cylinder to raise the lift arms and implement. As the implement is raised, the compression load on the top link is reduced and by the top link crank (1) will go back and allow the spool control valve (22) to move out by action of feedback spring. The spool cuts off the pilot port and resulting pressure rise unseats the regulator ball to allow pump pressure to return to reservoir. A decrease in implement draft allow the Link outer draft sensing to move back taking the spool control valve with it. This uncover the lowering port, allowing the lift arms and implement to fall until the increase in implement draft moves the control spool through the linkages to close the lowering port.
As the rocker shaft (12) rotates, the rock shaft cam tends to move away from the roller (2) and, in following the cam profile the roller and linkage allow the plunger to move out until the spool control cover the sleeve port (20) then the lift arms and implement are again held by the oil locked in the lift cylinder (34). As the pump pressure is unchanged the regulator ball will be held off its seat and pressure oil discharges to reservoir. NOTE : The distance raised depends onthe movement of the position control lever in quadrant. b. Draft Control (Dia. Pg 58)
The draft control lever (14), by moving the rocker draft control (13) of the operating link / link cpte DC actuating move the draft link relative to the DC feedback link outer assy this movement is transmitted to the control spool and oil flows in the appropriate direction until the resulting movement of the lift arms brings the implement draft to the desired setting. The spool then returns to the neutral position to cut off the oil flow.
The draft control system operate on the principle of draft loads i.e. resistance acting on the implement while it is being pulled through the ground. Load, actuates the DC feedback link outer assy (5) which is linked to the draft control spool of the valve. The position of the draft control lever (14) corresponds with a definite resistance of the implement being pulled through the ground. The implement penetrates into the ground until the pre selected operating resistance is reached. At this point the draft control linkage top link, bell crank / top link crank (1) (sensing element) acts on DC feedback link outer assy (5) which in turn transfer motion to DC feedback rod (8) which is connecting to DC actuating link (12) which actuates spool control lever (22). An increase in implement draft moves the link outer draft sensing (5) against the 60
c.
Draft control / sensing element.
1. The Tension or pressure forces acting on the Top link sensing element are converted into control signal i.e. These signal are taken up by the Top link crank (1) and transmitted to the spool control valve (22) for lifting or lowering action. 2. Operation In draft control mode, the lever (14) is set at particular position on the quadrant, top link attached to top link crank (1), under
