Abstract: The invention relates to a clamping device used for making up or breaking apart joints of drill pipe, drill collars and the like in mouse hole pipe during oil drilling operation. A clamping means of the device firstly clamps the drill pipe therebetween during its moving down and centripetally simultaneously by the self-weight of drill pipe to be clamped, then tightly clamps the drill pipe with a force generated by rollers' moving inwardly to the center of the device along the concavity of the turning plate with the rotation of a kelly. It can be used instead of a back tong when making-up joint in mouse hole pipe with a tong.

Abstract: A supercharged power tongs for making up or breaking apart drill tools used in oil or geologic drilling engineering is designed to take the place of B-type tongs. Supercharger and assist fluid cylinders are adopted in the gripping and torqueing devices respectively which are completely new provisions. An automatic make-up torque limitator is built in the control system. A pull-in locating device is used for moving the power tongs. This invention is particularly adequate for make-up and break apart operations on drill pipes, drill collars, kellys and lifting subs when the sizes of these drill tools vary from time to time, with no necessity for replacements of any components.