Patent ID: 6058811
Filing Date: 2000-05-09
Classification: E21B

Abstract:
A door mechanism for a power tong having a tong body with an open throat therein, the door mechanism, comprising:a door pivotally connected to the tong body adjacent a side of the open throat to extend at least partially across the open throat when in the closed position and to expose the open throat of the power tong when in the opened position to enable the power tong to be moved laterally on or off a tubular string;a latch arm pivotally connected to the door and movable between a latch arm closed position and a latch arm opened position, the latch arm including a latch head for engagement with a latch stop to latch the door in the closed position when both the door and the latch arm are in the closed position;a locking arm pivotally connected to the door for retaining the latch arm in the opened position;a locking stop secured to the latch arm; anda locking member secured to the locking arm for engagement with the locking stop to retain the latch arm in the latch arm opened position when the latch head is disengaged from the latch stop, the locking arm automatically pivoting relative to the latch arm during closing of the door to disengage the locking stop and the locking member.