Pipe gripping ram

Abstract

A ram is provided for use in the live and dead heads of an iron roughneck. The ram grips sections of pipe as connections are made or broken between the pipe sections. The ram includes a cylinder block having a bore and a fixed piston centered therein forming an annulus. An annular piston slides in and out of the cylinder block in the annulus. A tong mounted on the end of the end of the annular piston for gripping pipe includes a tong shoe and a tong die within the shoe. The tong die is capable of moving side-to-side within the shoe to self-center itself when gripping pipe. Pressurized gas or hydraulic fluid systems can be used to extend and retract the annular piston within the cylinder block.

Description

FIELD OF THE INVENTION [0001] The present invention relates to the field of rams for gripping drilling pipe. More specifically, the present invention relates to pipe gripping rams on automated iron roughnecks used on drilling rigs. BACKGROUND OF THE INVENTION [0002] Automated iron roughnecks are used on drilling rigs to perform the often dangerous tasks of making and breaking joints between sections of drilling pipe. An iron roughneck usually has two sets of jaws with pipe gripping tongs positioned in a vertical configuration, one on top of the other. The lower set of jaws or “dead head” holds the box end of the section of pipe connected to the drill string. The upper set of jaws or “live head” grasps the pin end of the section of pipe being joined to or removed from the drill string. The dead head tongs hold the drill string steady while the live head tongs turn the pin end of the pipe section clockwise to make a pipe connection or counter-clockwise to break a pipe connection. Depe...

AI Technical Summary

Benefits of technology

[0007] A first end of an annular piston slidably couples with the fixed piston such that the annular piston is capable of linear reciprocal motion along the annulus. The second end of the annular piston has a pipe gripping tong attached to it thereby forming a first chamber within the annular piston between its second end and the fixed piston. An annular ring or stop is attached to the first end of the annular piston and slides along the neck of the fixed piston. The combination of the fixed piston head, the annular piston and the annular ring forms a second annular chamber disposed about the fixed piston neck. The transition from the neck to the head on the fixed piston acts as a stop for the annular ring and keeps the annular piston from sliding out of the cylinder block as the annular ring contacts the head of the fixed piston.

[0010] The pipe-gripping tong mounted on the second end of the annular piston comprises a tong shoe and a tong die mounted within the shoe. The tong die has two surfaces with teeth for gripping a pipe. The two surfaces are at an angle to one another to form a shallow v-shaped groove. The shoe has a partial circular opening that allows the tong die to slide into the shoe and be secured by retainer ears mounted on top and bottom of the tong shoe. The tong shoe opening is slightly wider than the tong die such that the tong die has a small amount of side-to-side lateral movement within the shoe thereby allowing the tong die to self-center on a pipe in the event that the pipe is not exactly centered within the jaws of the live head or dead head tongs.

Problems solved by technology

Automated iron roughnecks are used on drilling rigs to perform the often dangerous tasks of making and breaking joints between sections of drilling pipe.

Depending on the diameter of the pipe used in the drill string and the amount of force used in turning the drill string to drill a hole, it may take several hundreds of foot-pounds of torque to break a connection between sections of pipe.

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