Long boring bar device of machine tool

A boring bar device of a machine tool, the boring bar device comprising:

• a turret configured to accommodate a plurality of tools;
• and
• a boring bar unit mounted on the turret,
• wherein the boring bar unit comprises:
• a holder detachably fastened to the turret;
• a head tool fastened to the boring bar;
• and
• a boring bar fastened to the holder, wherein the boring bar is capable of being clamped to or unclamped from the holder, wherein the head tool is capable of being clamped to or unclamped from the boring bar, wherein the boring bar is between the holder and the head tool such that the holder and head tool are fastened to opposite ends of the boring bar,
• wherein the holder comprises:
• a housing unit having a first receiving hole formed in a first side surface thereof;
• a first clamping unit formed inside the housing unit, wherein the first clamping unit extends into the first receiving hole such that the first clamping unit clamps or unclamps the boring bar;
• an inlet unit formed in a second side surface, opposite the first side surface, of the housing unit and supplying hydraulic pressure and pneumatic pressure into the housing unit;
• and
• an outlet unit formed in the first side surface of the housing unit, wherein the outlet unit is configured to communicate with the inlet unit,
• wherein the first clamping unit comprises:
• a rotating unit rotatably inserted into a bore of the housing unit;
• a first cylinder moving in a direction transverse to a rotation axis of the rotating unit, forward or backward, according to a rotating direction of the rotating unit;
• and
• a first locking unit pivotably installed along a first inclined surface formed at one side of the first cylinder,
• wherein the boring bar comprises:
• a main body unit extending between opposing first and second ends;
• a shank unit formed at the first end of the main body unit, wherein the shank unit is coupled to the first clamping unit;
• a connection unit attached directly to each of the first side surface of the housing unit and a circumferential surface of the main body unit, wherein the connection unit is configured to communicate with the outlet unit to supply hydraulic pressure and pneumatic pressure discharged from the outlet unit to channels inside of the main body unit;
• a second receiving hole formed in the second end of the main body unit;
• and
• a second clamping unit formed in the main body unit, wherein the second clamping unit is in the second receiving hole such that the second clamping unit clamps or unclamps the head tool,
• wherein the channels within the main body comprise
• a first flow path unit communicating with the connection unit and penetrating through the inside of the main body;
• and
• a second flow path unit communicating with the connection unit and penetrating through the inside of the main body, and
• wherein the second clamping unit comprises:
• a second cylinder configured to move in the direction transverse to the rotation axis of the rotating unit, forward or backward, by hydraulic pressure introduced through the first flow path unit or the second flow path unit;
• and
• a second locking unit pivotably installed along a second inclined surface formed at one side of the second cylinder, wherein movement of the second cylinder actuates the second locking unit to clamp and unclamp the head tool from the boring bar.