SAFETY DEVICE FOR SOIL TILLAGE TOOL Russian patent published in 1998 - IPC

FIELD: soil tillage equipment used in forestry and agriculture. SUBSTANCE: soil tillage tool has frame, working members 2 and hitching mechanism mounted on frame. Hitching mechanism has hydraulic cylinder 3 and hydraulic distributor, that are connected with tractor hydraulic system, and spring-biased probe 5 pivotally attached in front of working members and connected with distributing device 8. Slide valve of distributing device 8 is provided with four recesses. Two of recesses are is open state, when working member 2 is in its operating position, and adapted for connecting hydraulic cylinder 3 with one section of hydraulic distributor, and two other recesses are in closed state, when working tool 2 is in its operating position, and are communicated one with another via overflow channel and adapted for connecting hydraulic cylinder 3 with other section of hydraulic distributor. Timer is made integral with slide valve in the form of hydraulic cylinder with spring-biased piston, whose cavities are communicated one with another via return valve and adjustable throttle, which are connected in parallel. EFFECT: increased efficiency, simplified construction and enhanced reliability in operation. 4 dwg