| 摘要 |
An open throat power tong includes a tong body 15 having an open throat 17 therein, a partial ring member 12 for rotating a tubular during a makeup or breakout operation, at least two heads 16 rotatable with the partial ring for gripping engagement with the tubular, and a drive motor 18, 20 for powering rotation of the partial ring. A door 40, 50 is pivotally connected to a tong body adjacent a side of the open throat to allow the power tong to be moved laterally on and off the tubular string. A latch arm 56, 84 is movable between a closed position and an opened position, with the latch arm including a latch head 58, 86 for engagement with a latch stop 60, 61 to latch the door in the closed position. A locking arm 66, 94 includes a locking member 70 for engagement with a locking stop 72. The door mechanism significantly reduces the force and effort required to reliably latch the door in the closed position, thereby improving tong safety.
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