JPS57118836A - Hydraulic driving device for knock-out device of press machine - Google Patents

Abstract

PURPOSE:To enable independent setting of cushion force and knock-out force by installing a stop valve and a relief valve in series in the return oil path from the working oil chamber of a knock-out cylinder to the suction port of high pressure output oil chamber of a intensifying chamber. CONSTITUTION:The working oil chamber 3a of knock-out cylinder of the knock- out device of a press machine K and the high pressure output oil chamber 11 of an intensifying chamber 10 are connected by a parallel circuit of a feed oil path 17 and a return oil path 18. A valve 16 is provided in the feed oil path 17 and a stop valve 19A and a relief valve 19B is provided in the return oil path 18. In a state where the stop valve is closed and an intensifier is operated, the pressure oil in the high pressure output oil chamber 11 is pressed into a working oil chamber 3a through the feed oil path 17 and the valve 16, and the knock-out device K is knock-out driven. In a state where the stop valve is opened and the knock-out cylinder 3 is cushion operated, the feed oil path 17 is stopped by the valve 16, and the pressure oil is let flow through the return oil path 18 and the relief valve 19B, and the knock-out device K is cushion operated by set pressure of the relief valve 19B.