SYSTEM OF ACTIVE CLAMPING FORCE OF TOOL WITH AUTOMATIC BLOCKING OF PRESSURE SYSTEM OF TRACTOR HYDROSTREAM Russian patent published in 2015 - IPC A01B63/00 A01B15/00 

FIELD: agriculture.

SUBSTANCE: system comprises a hold-down cylinder structure and is arranged with the ability of connection to a source of hydraulic fluid under pressure through the multipositional valve of selective control. The valve is connected between the source and the hold-down system and has neutral, upper, lower and float positions. The system also comprises a control pressure valve, a fluid line, a load sensing line, a valve means in the fluid line. The controlled pressure valve has an inlet and outlet. The valve means in the fluid line is configured to open and close the fluid line for the fluid flow. And the valve means comprises the means adapted to closing the fluid line when the cylinder structure is not extended, and the means for opening the fluid line when the cylinder structure is extended. The hydraulic circuit comprises an adjustment pump, a multipositional valve of selective control, a load-sensing connection between the pump and the external load on the valve and the valve means for actuating the pump when the valve is transferred from the neutral position to the first position, and to maintain the pump on when the valve returns to its neutral position.

EFFECT: use of an adjustable load sensing power source only when the cylinders are extended.

13 cl, 3 dwg