Hydraulic striking device

A hydraulic striking device that has a piston disposed in a cylinder to move up and down, an upper chamber formed at an upper portion between the piston and the cylinder, and a lower chamber formed at a lower portion between the piston and the cylinder,

• the hydraulic striking device comprising:
• a piston control valve controlling the piston moving up and down;
• a stroke force control valve controlling the piston control valve;
• a rock strength sensing valve controlling the stroke force control valve;
• a fourth supply line connecting the rock strength sensing valve and the piston control valve to each other;
• and
• a third actuating line connecting the stroke force control valve and the piston control valve to each other,
• wherein the piston control valve has:
• a body;
• a piston control valve chamber formed in the body;
• a slider moving up and down between the body and the piston control valve chamber;
• and
• a first groove formed at the slider,
• when the slider is positioned at a first down-position, the fourth supply line and the third actuating line are connected through the first groove, and when the slider is positioned at a first up-position, the fourth supply line and the third actuating line are disconnected, and
• when the rock strength sensing valve is operated and the fourth supply line and the third actuating line are connected to each other, working fluid is supplied through the fourth supply line and the third actuating line and operates the stroke force control valve.