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US 6,311,792 B1Granted
Casing clamp
AssigneeTesco Corporation
InventorsStephen F. Scott, Kevin Nikiforuk
Life of this patent
Estimating the term…
Abstract
A clamp for gripping casing strings is disclosed. A series of radially arranged spring biased slips are mounted in a housing attached to a top drive. A hydraulic system is used to release the slips from the gripping position upon a casing string.
Claims32
A clamp for use with a top drive for gripping and turning a drill string formed of pipe, the clamp comprising:
- slips positioned to grip and support the pipe, drive means for moving the slips radially inwardly into a pipe gripping position and radially outwardly to a pipe releasing position, and an attachment means for connecting the clamp to a top drive for wellbore drilling.
A clamp for use with a top drive for gripping and turning a drill string formed of pipe, the clamp comprising:
- slips positioned to grip and support the pipe, drive means including a hydraulic system for moving the slips radially inwardly into a pipe gripping position and radially outwardly to a pipe releasing position, and an attachment means for connecting the clamp to a top drive.
A clamp for use with a top drive for gripping and turning a drill string formed of pipe, the clamp comprising:
- slips positioned to grip and support the pipe, drive means for moving the slips radially inwardly into a pipe gripping position and radially outwardly to a pipe releasing position, a stabbing spear extending out between the slips and formed to fit within the pipe to be gripped by the clamp and an attachment means for connecting the clamp to a top drive.
Dependencies are inferred from the claim text.