Pravel, Gambrell, Hewitt, Kirk & Kimball
Bowl structure
 A well bowl has an opening extending through the bowl, at least a portion of which is formed in the shape of a pyramidal frustum. A plurality of slips are movable along the pyramidal surfaces and together define an inner opening, the slip surfaces which define the inner opening being adapted to engage and hold the outer surface of a length of drill pipe when the slips are moved toward the smaller end of the bowl opening. The slips are disengaged from the drill pipe when they are moved away from the smaller end of the bowl opening and have outer surfaces shaped to engage at least a portion of the surfaces which define the bowl opening when the slips move between their engaging and disengaging positions. The slips are guided along the surfaces which define the bowl for maintaining the slip surfaces which engage the pipe oriented in their pipe engaging positions when they move along the bowl surfaces. 
Bowen Tools, Inc.
E
E21B
inventional
Joseph H.
Byrne, Jr.