| 摘要 |
A camming member for power tongs, comprising a ring-shaped body including a central opening formed therein, the body being .rotatable about a point within the central opening, the body further including a slot, the slot opening through the body and communicating with the central opening; a ring-shaped drive member including a central opening formed therein, the drive member being rotatable about the point, the drive member further including a slot, the slot opening through the drive member and communicating with the central opening of the drive member, the slot of the drive member being alignable with the slot of the body, the drive member being slidably mounted on the body such that the drive member may rotate independently of the body and such that the drive member is radially supported by the body; and a detent and stop mechanism, mounted on the camming member, for allowing the body and the drive member to partially rotate relative to one another to a desired engaged position and then to maintain the engaged position as the camming member rotates. Additionally, a the body of the camming member may also have a first cam surface facing the central opening and curving inward toward the point, and a second cam surface facing the central opening and curving inward toward the point, at least a portion of the second cam surface being axially aligned with and offset from the first cam surface.
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