Abstract: The invention is a lockout valve used in a hydraulic circuit to prevent leakage in a static condition; the lockout valve does not require outside force to hold the lockout open once flow across the lockout is established due to the positioning of an orifice ring around the poppet upstream of the poppet seat with the closing area acting on the poppet in conjunction with a spring which senses the pressure downstream of the orifice ring so that when there is sufficient flow across the orifice ring, the force created by the opening area on the poppet, which is located upstream of the orifice ring, will exceed the combined force of the spring and the closing area so that the lockout valve will remain open without an outside force so long as sufficient flow is maintained across the poppet.

Abstract: A sequencing valve utilized with a tractor-propelled planter having two row arms which pivot downward to the ground in an alternating sequence as the planter changes directions in the field. The sequencing valve is connected with the conventional hydraulic system which raises and lowers the planter at the end of each row so as to automatically lower alternate marker arms. This is achieved by pressurizing opposite ends of the sequencing valve spool for longitudinal movement through a cam means, causing the spool to rotate during movement in one direction whereby alternating lowering of the planter arms is achieved each time the planter is hydraulically lowered to the ground.