Power tong interlock system

A method for controlling a tong, comprising:

• receiving a signal, at a rotation change control device, representing that a run/pull mode selector is in a first configuration associated with running tubulars into a well;
• receiving a signal, at the rotation change control device, representing that a rotation speed selector is in a high-speed setting, wherein the tong is configured to rotate at a first speed when the rotation speed selector is in the high-speed setting;
• and
• automatically permitting actuation of the rotation change control device and a tong motor control valve to cause the tong to rotate in a make-up direction;
• and
• automatically preventing actuation of the rotation change control device and the tong motor control valve to cause the tong to rotate in a break-out direction that is opposite to the make-up direction, until receiving a signal representing that the rotation speed selector has been actuated to a low-speed setting, wherein the tong is configured to operate at a second speed that is less than the first speed when the rotation speed selector is in the low-speed setting.

A tong, comprising:

• gripping jaws configured to grip a tubular;
• a motor configured to rotate the jaws and thereby rotate the tubular in either a make-up direction or a break-out direction;
• and
• a control system in communication with the motor, the control system comprising:
• a tong motor control valve that is selectively actuatable to cause rotation of the tong in a first direction or in a second direction;
• a run/pull mode selector configured to actuate between a first configuration for running tubulars into a well and a second configuration for pulling tubulars from the well;
• a rotation speed selector configured to actuate between a high-speed setting configured to cause the motor to drive the tong to rotate at a first speed, and a low-speed setting configured to cause the motor to drive the tong to rotate at a second speed, the first speed being greater than the second speed;
• and
• a rotation change control device configured to selectively prevent or permit actuation of the tong motor control valve based on whether the run/pull mode selector is in the first configuration or the second configuration and whether the rotation speed selector is in the high-speed setting or the low-speed setting.