HYDRAULIC DRIVE FOR MOVING LOWER ROLL OF FOUR-ROLL SHEET BENDING MACHINE Russian patent published in 2003 - IPC

FIELD: plastic metal working, namely constructions of four-roll sheet bending machines. SUBSTANCE: hydraulic drive for moving lower roll of four-roll sheet bending machine includes hydraulic cylinders, pressure source, hydraulic system for synchronizing operation of hydraulic cylinder and hydraulic system for protecting against overloads. Pressure source is communicated with cavities of hydraulic cylinders through reversing hydraulic distributor and controlled non-return valves. Hydraulic system for protecting upper and lower rolls against overload is in the form of safety valve. Effort for pressing lower roll to upper roll is controlled by means of safety valve connected through controlled non-return valve with protection hydraulic system between non-return valves and safety valve of said protection system. EFFECT: increased useful life period of four-roll sheet bending machine. 2 dwg