Patent ID: 8127901

Claim:
A hydraulic damping device comprising: a cylinder, said cylinder having a front opening in a front end thereof and a rear opening in a rear end thereof; a front cap sealed to the front opening of said cylinder; a rear cap sealed to the rear opening of said cylinder, said rear cap having a bottom accommodation chamber, a gasket ring disposed in said bottom accommodation chamber, and a center axle hole in communication with said bottom accommodation chamber; a hydraulic fluid filled in said cylinder; a piston rod, said piston rod having a rod body inserted through the gasket ring of said rear cap and extending out of said cylinder, a pin axially extending from one end of said rod body and suspending inside said cylinder, and a retainer connected to said pin remote from said rod body; a rigid valve block coupled to said pin and stopped against said rod body of said piston rod, said rigid valve block having a diameter smaller than the inner diameter of said cylinder and a plurality of through holes axially extending through front and rear sides thereof; and a piston coupled to said pin and axially movable along said pin between said retainer and said rigid valve block, said piston having an outer diameter smaller than the inner diameter of said cylinder and greater than the outer diameter of said rigid valve block and a plurality of through holes axially extending through front and rear sides thereof, the number of the through holes of said piston being greater than the number of the through holes of said rigid valve block, a number of the through holes of said piston being respectively aimed at the through holes of said rigid valve block.