HYDRAULIC DRIVE OF STRAIGHTENING-STRETCHING MACHINE FRONT HEAD Russian patent published in 2014 - IPC B21D3/12 

FIELD: process engineering.

SUBSTANCE: invention relates to metal forming, particularly, to straightening-stretching machine hydraulic drives. Proposed hydraulic drive of the straightening-stretching machine front head comprises working and return hydraulic cylinders, safety valves, fluid pressure control valves, a pressure fluid line, a working fluid source, a load control valve, a filling valve, a filling tank, a drain fluid line, a tank and two extra two-way fluid pressure control valves. At the breakage of an article being straightened by stretching, slides of the fluid pressure control valves are quickly displaced under the action of fluid pressure caused by the fluid pressure drop in their control cavities from an initial position to the second working position. This results in the communication of the hydraulic cylinder chambers with the low-pressure line while the fluid drain from the return hydraulic cylinder chambers is shut off and can be resumed solely via the safety valve.

EFFECT: longer life.

7 cl, 2 dwg