US Patent 10006260 Power tong spool valve speed limiting system

A power tong assembly includes a power tong and a speed limiting system operably coupled to the power tong. The power tong is configured to grip and rotate a tubular segment in a first direction to make-up a threaded connection with the tubular segment and in a second direction to break-out the threaded connection with the tubular segment. The speed limiting system is configured to selectively allow the power tong to rotate the tubular segment in one of the first direction and the second direction at a maximum speed while limiting the power tong to rotate the tubular segment in the other of the first direction and the second direction below the maximum speed.