Stroke adjustment mechanism of hydraulic impact apparatus

摘要

PROBLEM TO BE SOLVED: To automatically adjust the stroke of a piston corresponding to the change in rock quality as an object to be crushed.;SOLUTION: In this hydraulic hammering deice, a front liquid chamber 3 is communicated with a high pressure circuit 7, a rear liquid chamber 4 is switched and communicated to a high pressure circuit 7 and a low pressure circuit 9 so that the piston 2 reciprocate. A switching valve control port 10 communicated with the control chamber 21 of the switching valve 20 and a short stroke point 13 are provided on the rear side of the front liquid chamber 3, and the short stroke port 13 and the control chamber 21 of the switching valve 20 are connected to each other through a stroke adjusting valve 30, and a stroke adjust valve control port 14 communicated with an adjust chamber 31 of the stroke adjusting valve 30 and a high pressure port 15 are provided on the front of the front liquid chamber 3. The piston 2 is provided with a communicating groove 16 for communicating the high pressure port 15 and the stroke adjusting valve control port 14 with each other to switch a spool 32 of the stroke adjust valve 30 to the short stroke side when the piston 2 moves forward over the designated hammering position.;COPYRIGHT: (C)2004,JPO