Hydraulically Striking Device

Abstract

A hydraulically striking device having a cylinder body, the cylinder body forming a cylinder therein, a piston in the cylinder body, configured to move by means of a hydraulic fluid so as to reciprocate between a first and a second position in the cylinder. According to the invention, a first control channel and a second control channel extend from the valve, a first port and a second port open into the cylinder, wherein the first port is coupled to the first control channel and the second port is coupled to the second control channel, the piston having at least one flow space which is arranged to be selectively coupled to the first port and to the second port and allowing the hydraulic fluid to flow in one of the control channels in one direction so as to provide circulation of the hydraulic fluid controlling the valve.

What is claimed: 
     
         1 . A hydraulically striking device comprising
 a cylinder body, the cylinder body forming a cylinder therein,   a piston in the cylinder body, configured to move by means of a hydraulic fluid so as to reciprocate between a first and a second position in the cylinder, and   a valve for controlling the movement of the piston, wherein   a first control channel and a second control channel extend from the valve,   a first port and a second port open into the cylinder at different points in the axial direction and at a distance from one another,   wherein the first port is coupled to the first control channel and the second port is coupled to the second control channel, and   wherein the piston comprises at least one flow space which is arranged to be selectively coupled to the first port and to the second port and allowing the hydraulic fluid which controls the valve in the first control channel and in the second control channel to flow in one of the control channels in one direction so as to provide circulation of the hydraulic fluid controlling the valve.   
     
     
         2 . The hydraulically striking device according to  claim 1 , characterized in that the piston comprises one flow space, which is a uniform groove between a first edge and a second edge of the flow space, wherein the edges act as closing surfaces of the flow of the hydraulic fluid. 
     
     
         3 . The hydraulically striking device according to  claim 1 , wherein the valve comprises a moving member which is configured to move for a specific distance from its initial position within the valve and to take hydraulic fluid in an amount corresponding to the movement and to return hydraulic fluid when moving back to the initial position. 
     
     
         4 . The hydraulically striking device according to  claim 1 , wherein the hydraulically striking device further comprises a third port, a fourth port, a pressure line and a return line, wherein the third port and the fourth port open into the cylinder at different points in the axial direction and at a distance from one another and from the first port and the second port, the piston comprising at least one flow space which is arranged to be selectively coupled to the first port, to the second port, to the third port and to the fourth port, wherein the third port is coupled with the pressure line and the fourth port is coupled with the return line. 
     
     
         5 . The hydraulically striking device according to  claim 4 , wherein a choke is provided in the fourth port or in the return line. 
     
     
         6 . The hydraulically striking device according to  claim 3 , wherein the direction of movement of the piston is changed by the position of the moving member. 
     
     
         7 . The hydraulically striking device according to  claim 3 , wherein the moving member is a spool or a poppet or a combination of a spool and a poppet of the valve. 
     
     
         8 . The hydraulically striking device according to  claim 1 , wherein in the selective coupling with the piston disposed in the first or in the second position, the piston is arranged to block the flow communication to at least one of the control channels by blocking the port connected to that control channel. 
     
     
         9 . The hydraulically striking device according to  claim 1 , wherein in the first position of the piston, the flow space connects the third port to the first port and the piston blocks the second port and the fourth port, allowing the hydraulic fluid to flow via the first control channel. 
     
     
         10 . The hydraulically striking device according to  claim 9 , wherein in the second position of the piston, the piston blocks the third port and the flow space connects the first port and the second port to the fourth port, allowing the hydraulic fluid to flow from the valve via both control channels. 
     
     
         11 . The hydraulically striking device according to  claim 1 , wherein in the second position of the piston, the piston blocks the third port and the first port and the flow space connects the second port to the fourth port, the hydraulic fluid flowing via the second control channel. 
     
     
         12 . The hydraulically striking device according to  claim 11 , wherein in the first position of the piston, the flow space connects the third port to the first port and to the second port and the piston blocks the fourth port, allowing the hydraulic fluid to flow via both control channels. 
     
     
         13 . The hydraulically striking device according to  claim 1 , wherein in the first position of the piston, the flow space connects the third port to the first port and the piston blocks the second port and the fourth port, allowing the hydraulic fluid to flow via the first control channel. 
     
     
         14 . The hydraulically striking device according to  claim 13 , wherein in the second position of the piston, the piston blocks the third port and the first port and the flow space connects the second port to the fourth port, allowing the hydraulic fluid to flow from the valve via the second control channel. 
     
     
         15 . The hydraulically striking device according to  claim 1 , wherein when the first control channel and the second control channel are provided in flow communication, the flow is divided among the channels. 
     
     
         16 . The hydraulically striking device according to  claim 1 , wherein the piston has a first longitudinal center axis and the valve has a second longitudinal center axis, wherein the second longitudinal center axis coincides with the first longitudinal center axis. 
     
     
         17 . The hydraulically striking device according to  claim 1 , wherein the hydraulically striking device is a rock drilling machine. 
     
     
         18 . The hydraulically striking device according to  claim 2 , wherein the valve comprises a moving member configured to move for a specific distance from its initial position within the valve and to take hydraulic fluid in an amount corresponding to the movement and to return hydraulic fluid when moving back to the initial position. 
     
     
         19 . The hydraulically striking device according to  claim 2 , wherein the hydraulically striking device further comprises a third port, a fourth port, a pressure line and a return line, wherein the third port and the fourth port open into the cylinder at different points in the axial direction and at a distance from one another and from the first port and the second port, the piston comprising at least one flow space which is arranged to be selectively coupled to the first port, to the second port, to the third port and to the fourth port, wherein the third port is coupled with the pressure line and the fourth port is coupled with the return line. 
     
     
         20 . A hydraulically striking device comprising
 a cylinder body, the cylinder body forming a cylinder therein,   a piston in the cylinder body, configured to move by means of a hydraulic fluid so as to reciprocate between a first and a second position in the cylinder, and   a valve for controlling the movement of the piston, wherein the valve comprises
 a moving member configured to move for a specific distance from its initial position within the valve and to take hydraulic fluid in an amount corresponding to the movement and to return hydraulic fluid when moving back to the initial position, 
 a first control channel and a second control channel extending from a closed space of the valve enabling hydraulic fluid to flow to the closed space of the valve and to change the volume of the fluid inside the valve by moving the moving member, 
 a first port and a second port open into the cylinder at different points in the axial direction and at a distance from one another, wherein the first port is coupled to the first control channel and the second port is coupled to the second control channel, 
   wherein the piston comprises at least one flow space which is arranged to be selectively coupled to the first port and to the second port and allowing the hydraulic fluid which controls the valve in the first control channel and in the second control channel to flow in one of the control channels in one direction so as to provide circulation of the hydraulic fluid controlling the valve.