Abstract: The apparatus includes a mast, an elevator and a tubing spider for suspending a string of well tubes or rods, a rack for storing well tubes or rods, a manipulator and a swivel head for screwing and unscrewing the string carried by the manipulator boom. To axially align the last tube or rod with the string the apparatus is provided with centering guides for centering the upper and the lower ends of the tube or rod and a gripping device for gripping the upper end of the string. The centering guide for centering the upper end of a well rod or tube forms part of a lifting frame, which in turn is a constituent of the elevator for suspending a string of well tubes or rods. The centering guide for centering the lower end of the rod or tube forms part of an automatic tong assembly for making up and breaking out joints of rods, which assembly is used with the claimed apparatus and also comprises the swivel head and the gripping device for gripping the upper end of the string of well tubes or rods.

Abstract: The apparatus includes a mast, an elevator and a tubing spider for suspending a string of well tubes or rods, a rack for storing well tubes or rods, a manipulator and a swivel head for screwing and unscrewing the string carried by the manipulator boom. To axially align the last tube or rod with the string the apparatus is provided with centering guides for centering the upper and the lower ends of the tube or rod and a gripping device for gripping the upper end of the string. The centering guide for centering the upper end of a well rod or tube forms part of a lifting frame, which in turn is a constituent of the elevator for suspending a string of well tubes or rods. The centering guide for centering the lower end of the rod or tube forms part of an automatic tong assembly for making up and breaking out joints of rods, which assembly is used with the claimed apparatus and also comprises the swivel head and the means for gripping the upper end of the string of well tubes or rods.

Abstract: An automatic wrench comprises a high-torque, a low-torque, and a locking device. The wrench control system includes a torque detector and a rotation angle detector, in response to whose signals passing through an AND gate a control unit delivers a command to end the thread tighening by the rotation actuator of the high-torque device in screwing a pipe string together or to end the initial loosening of the thread with the aid of the same actuator in screwing it apart. The control unit incorporates a unit for monitoring the duration of the command execution, which stops operation of the high-torque device if no signal comes from said AND gate during the time alloted to accomplish the tightening or the initial loosening of the thread.