Patent ID: 7228781

Claim:
A hydraulic control system for operating a machine tool for processing material, comprising at least one hydraulic cylinder having a bottom space ( 1 . 1 . 2 ) and an annular space ( 1 . 1 . 1 ), and hydraulic means for setting a higher maximum counter-pressure in the annular space ( 1 . 1 . 1 ) for impact damping, said hydraulic means comprising: a first main valve element ( 2 . 4 . 0 ) disposed in a fluid flow line from said annular space ( 1 . 1 . 1 ) to a hydraulic fluid reservoir (T), a nozzle ( 2 . 4 . 1 . 1 ) for delaying opening movement of the first main valve element ( 2 . 4 . 0 ) in case of sudden rapid movement of said cylinder; and a pressure valve ( 2 . 4 . 2 ) for simultaneously limiting, as pilot control of the first main valve element ( 2 . 4 . 0 ), the pressure in the annular space ( 1 . 1 . 1 ) in said cylinder ( 1 . 1 ) to a pressure set at the pressure valve ( 2 . 4 . 2 ); said nozzle ( 2 . 4 . 1 . 1 ) and pressure valve ( 2 . 4 . 2 ) causing the generation of a limited counter-pressure for impact damping in said annular space ( 1 . 1 . 1 ), said impact damping being assisted by a pilot-control valve ( 2 . 4 . 3 ) controlling the first main valve element ( 2 . 4 . 0 ).