TILLAGE TOOL UNIT Russian patent published in 1999 - IPC

FIELD: agricultural engineering, in particular, working tools capable of rounding obstacles. SUBSTANCE: tillage tool unit 10 has tine 18 positioned so that it may turn for rounding obstacle in ground. Hydraulic cylinder 22 prevents tine from displacement from normal working position. Force applied by tine 18 for overcoming resistance of hydraulic cylinder 22 is initially high, but this force is decreased upon predetermined displacement of tine 18 and consequently upon predetermined displacement, when hydraulic cylinder 22 is withdrawn. It facilitates tine 18 to overcome obstacle without damaging tine 18. According to first version, valve is positioned within hydraulic cylinder and insert within hollow piston block is cooperating with head on tube extending through cylinder. According to second version, working tool has outer valve with cam acting upon valve body in fluid supply line. Hydraulic circuit of working tool has pressure multiplier and locking valve for reducing pressure in hydraulic cylinder. EFFECT: increased efficiency and improved quality of tilled soil. 31 cl, 11 dwg