Hammer Raising Device

Abstract

There is provided a hammer raising device. The hammer raising device is configured to increase striking intensity by eliminating fluid resistance when a piston raised upward moves downward. To achieve this, the hammer raising device includes a hydraulic control valve that controls a supply of a fluid, a sub cylinder to which the fluid is supplied by an operation of the hydraulic control valve, a sub piston that is partially accommodated within the sub cylinder, and is raised or lowered by the fluid, a main piston that comes in close contact with a longitudinal end of the sub piston to be raised by the raising of the sub piston, and is lowered when the closely contacted longitudinal end of the sub piston is separated, and a main cylinder that accommodates the main piston.

We claim: 
     
         1 . A hammer raising device comprising:
 a sub cylinder to which a fluid is supplied by an operation of a hydraulic control valve;   a sub piston that is partially accommodated within the sub cylinder, and is raised or lowered by the fluid;   a main piston that comes in close contact with a longitudinal end of the sub piston to be raised by the raising of the sub piston, and is lowered when the closely contacted longitudinal end of the sub piston is separated;   a main cylinder that accommodates the main piston; and   a switching valve that separates the sub piston from the main piston when the main piston reaches a maximum point where the main piston is able to move within the main cylinder.   
     
     
         2 . The hammer raising device of  claim 1 , wherein the sub piston includes a first sub piston, and a second sub piston, and the first sub piston and the second sub piston alternately raises the main piston.