| 摘要 |
A method of locking a power tong having an activation valve and a door. A first step involves providing a movable body adapted to disable the activation val ve of the power tong by preventing movement of a valve shaft required for activation of the activation valve. The movable body has a locking position and a release position. In the locki ng position, the movable body is moved into a position where it prevents movement of the valv e shaft. In the release position, the movable body is moved out of the locking position to permit normal activation of the activation valve. A second step involves mechanically linking movement of the door and movement of the movable body so that, when the door is open, th e movable body is moved to the locking position and when the door is closed, the movab le body is moved to the release position.
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