Centering control type drill system for offshore structure

Abstract

Disclosed herein is a centering control type drill system for offshore structures. The centering control type drill system is installed to be elevated in a derrick for offshore drilling and rotates a drill string. The centering control type drill system includes a motor providing rotational force for offshore drilling, a gear box unit placed below the motor and increasing the rotational force of the motor, a main rotary shaft placed below the gear box unit and rotating the drill string; an intermediate bracket provided to the gear box unit, a dolly bracket disposed to be elevated in the derrick, a first dolly arm retractably coupled between the dolly bracket and the intermediate bracket by a hinge, a second dolly arm retractably coupled between the dolly bracket and the intermediate bracket by a hinge, and a cylinder rotating the second dolly arm about the hinge.

1 . A centering control type drill system for offshore structures, which is installed to be elevated in a derrick for offshore drilling and rotates a drill string, the centering control type drill system comprising:
 a motor providing a rotational force for offshore drilling;   a gearbox unit placed below the motor and increasing rotational force of the motor;   a main rotary shaft placed below the gearbox unit and rotating the drill string;   an intermediate bracket provided to the gearbox unit;   a dolly bracket disposed to be elevated in the derrick;   a first dolly arm retractably coupled between the dolly bracket and the intermediate bracket by a hinge;   a second dolly arm retractably coupled between the dolly bracket and the intermediate bracket by a hinge; and   a cylinder rotating the second dolly arm about the hinge.   
     
     
         2 . The centering control type drill system according to  claim 1 , wherein the first dolly arm comprises an upper dolly arm placed at an upper portion of the dolly bracket, and the second dolly arm comprises a lower dolly arm placed at a lower portion of the dolly bracket. 
     
     
         3 . The centering control type drill system according to  claim 1 , wherein the first dolly arm comprises an arm housing having a hollow structure, coupled to the dolly bracket by the hinge, and formed with a plurality of locking holes on an outer circumference thereof in a longitudinal direction thereof; and an arm rod coupled to the intermediate bracket by the hinge, disposed to be slidably inserted into the arm housing, and provided with a locking projection formed on an outer circumference thereof in a longitudinal direction thereof and resiliently inserted into the locking hole, and
 wherein the second dolly arm comprises an arm housing having a hollow structure, coupled to the dolly bracket by the hinge, and formed with a plurality of locking holes on an outer circumference in a longitudinal direction; and an arm rod coupled to the intermediate bracket by the hinge, disposed to be slidably inserted into the arm housing, and provided with a locking projection formed on an outer circumference thereof in a longitudinal direction thereof and resiliently inserted into the locking hole.   
     
     
         4 . The centering control type drill system according to  claim 3 , wherein the locking projection is resiliently disposed on a spring. 
     
     
         5 . The centering control type drill system according to  claim 1 , wherein the first dolly arm comprises an arm housing having a hollow structure and coupled to the dolly bracket by the hinge; an arm rod coupled to the intermediate bracket by the hinge and disposed to be slidably inserted into the arm housing; and a servomotor internally secured to the arm housing and having a rotary shaft screw-coupled to a rear side of the arm rod, and
 wherein the second dolly arm comprises an arm housing having a hollow structure and coupled to the dolly bracket by the hinge; and an arm rod coupled to the intermediate bracket by the hinge and disposed to be slidably inserted into the arm housing; and a servomotor internally secured to the arm housing and having a rotary shaft screw-coupled to a rear side of the arm rod.   
     
     
         6 . The centering control type drill system according to  claim 1 , wherein the dolly bracket comprises a roller. 
     
     
         7 . A centering control type drill system for offshore structures, which is installed to be elevated in a derrick for offshore drilling and rotates a drill string, the centering control type drill system comprising:
 a motor providing rotational force for offshore drilling;   a gearbox unit placed below the motor and increasing the rotational force of the motor;   a main rotary shaft placed below the gearbox unit and rotating the drill string;   an intermediate bracket provided to the gearbox unit;   a dolly bracket disposed to be elevated in the derrick;   a plurality of dolly arms retractably coupled between the dolly bracket and the intermediate bracket by a hinge; and   a cylinder rotating one of the dolly arms about the hinge.   
     
     
         8 . The centering control type drill system according to  claim 7 , wherein each of the dolly arms comprises:
 an arm housing having a hollow structure and coupled to the dolly bracket by the hinge; and   an arm rod coupled to the intermediate bracket by the hinge and disposed to be slidably inserted into the arm housing.