control the time for valve closing application_number US 9807602 A description the prior art system of fig1 includes a frame 10 a pivotal boom 12 and first and second hydraulic cylinders 14 and 16 which are pivotally secured to the frame and the boom for oscillating the boom the numeral 18 designates the piston for cylinder 14 and the numeral 20 designates the piston for cylinder 16 piston rods 26 connect the pistons to the boom the boom is pivotally connected to the frame 10 by means of the pivotal connection 28 a first conduit 30 interconnects the cylinders 14 and 16 above the respective pistons thereof a directional control valve 32 used by the operator to control the movement of boom 12 through the cylinders 14 and 16 is connected to the lower portion of each of the cylinders by conduits 34 and 36 respectively it is this configuration of fig1 that is unable to smoothly deal with the inertia of the moving boom and bucket mass and which cannot achieve an instantaneous stop of the boom during its pivotal motion with reference to fig2 the improvement of this invention over the conventional structure in fig1 is illustrated similar numerals have been shown in fig2 which correspond to like components in fig1 attention is directed to the first and second hydraulic zones 22 and 24 above and below each of the pistons 18 and 20 respectively added to the system of fig1 as shown in fig2 is a first hydraulic control line 38 which interconnects conduits 34 and 36 a second hydraulic control line 40 is parallel to line 38 and also interconnects lines 34 and 36.