Device for activation of gripping jaws in continuously rotating torque tongs for use under pulling and opening of threaded connections

Abstract

Continuously rotating power tong for making the threaded connections ( 2 ) of pipes, primarily used for drilling for oil and gas in the petroleum industry. The power tong comprising radially movable jaw sections ( 22 ), connected to a driving disc ( 12 ), where hydraulic pumps ( 16, 17 ) are mounted, the pumps ( 16, 17 ) being driven by an endless chain ( 15 ) through gears ( 35 ) and the chain ( 15 ) being driven by motors ( 18, 19 ) through gears ( 27, 28 ).

1 . A torque tong for assembling pipes with threaded connections for use in subterranean drilling, as known from the petroleum industry, the torque tong comprising a radial opening for inserting and/or removing pipe or threaded connections and a drive ring non-rotatably supported in surrounding structures, wherein the drive ring is connected to a structure arranged with radially displaceable gripping jaws, and wherein the transfer of power for operating pumps disposed on the rotary drive ring with the radial opening is accomplished through an endless chain driven by motors,
 wherein the motors are rotationally rigidly synchronized by means of a synchronization chain via gear wheels, and the chain drives a gear wheel or wheels connected to the hydraulic pumps, with a clutch having a backstop being provided between the pumps and the gear wheels.   
     
     
         2 . The torque tong of  claim 1 , further comprising a clutch between the motors, the clutch being configured for activating and deactivating rotation. 
     
     
         3 . The torque tong of  claim 2 , wherein the motors are connected to and disconnected from the gear wheels by means of the clutch, so that the drive ring is able to rotate with no influence from the motors. 
     
     
         4 . The torque tong of  claim 2 , wherein the clutch comprises splined input and output shafts connected by a shiftable sleeve operated by hydraulic or electrical signals. 
     
     
         5 . The torque tong of  claim 1 , wherein between the pumps a sequence valve is disposed controlling the oil flow depending on the direction of rotation of the pumps. 
     
     
         6 . The torque tong of  claim 1 , wherein the backstop further comprises a spring. 
     
     
         7 . The torque tong of  claim 1 , wherein the drive ring is provided with a cogging engaging the motors via a gear wheel. 
     
     
         8 . The torque tong of  claim 7 , wherein the motors are rotationally rigidly synchronized with a gear wheel, so that, when the rotation passes by the radial opening, proper engagement with the cogging of the drive ring is maintained. 
     
     
         9 . The torque tong of  claim 1 , wherein the endless chain runs over end rollers on each side of the radial opening. 
     
     
         10 . The torque tong of  claim 1 , further comprising guides mounted on the drive ring, wherein the guides are for keeping the chain in a correct position relative to the center of rotation. 
     
     
         11 . The torque tong of  claim 1 , wherein the pump is a variable hydraulic pump which down-regulates the volume when the pressure increases. 
     
     
         12 . The torque tong of  claim 1 , wherein the pump is a fixed volume pump which is activated to supply pressure when the gripping jaws are to be pulled away from the pipe wall. 
     
     
         13 . The torque tong of  claim 1 , wherein the gripping jaws comprise an inner piston connected to the outer steel structure through an adapter. 
     
     
         14 . The torque tong of  claim 1 , further comprising a hydraulic unit mounted on the rotary drive ring, the hydraulic unit being provided with separate hydraulic tank and piping.