US Patent 7681649 Power slips

A slip assembly for gripping pipe during well drilling operations has a housing with a hole for receiving a section of pipe. Pockets in the housing are spaced circumferentially around the hole. Each of the pockets has side walls that face toward each other and are connected to each other by a back wall that has at least one ramp surface. A slip segment is located in each pocket, each slip segment having side edges that engage the side walls of one of the pockets. Each slip segment has a back side with a ramp surface that engages the ramp surface on the back wall of the pocket. Each of the slip segments is movable within its pocket from an upper outward position to a lower inward position in gripping engagement with the pipe.