Dresser Industries, Inc.

Howard E Mitchell

William C Saxman

A raise boring system is provided that allows the raise boring head to be easily and efficiently lowered back through the completed raise hole. The raise head includes a multiplicity of rolling cutters positioned in saddles that are firmly affixed to the body of the raise head. These fixed saddles and rolling cutters comprise the primary cutting stage of the raise head. A multiplicity of retractable gage cutters are located radially outside of the primary cutting stage. The retractable gage cutters comprise rolling cutters positioned in moveable saddles. The moveable saddles and rolling cutters can be selectively withdrawn inside the primary cutting stage. A hydraulic-pneumatic system is provided for withdrawing the retractable gage cutters.

Raise boring head with retractable gage cutters

A raise bit for enlarging a pilot hole into a larger diameter hole by disintegrating the earth formations that surround the pilot hole is provided with a cutter arrangement that provides a continuous angle bottom configuration in the range of 134.degree. to 60.degree..

Steep angle raise bit

The body of a raise boring head is produced from a truncated cone. A variety of efficient and economical methods such as spin-forming, casting, rolling, etc. may be used in producing the truncated cone body. A multiplicity of rolling cutters positioned in cutter saddles are mounted on the truncated cone body. The mounting surfaces for the cutter saddles are on a continuous plane. The continuous plane can be produced on the truncated cone body in one turning operation. The raise boring head is self-cleaning due to the natural tendency of the cuttings to slide toward the periphery of the truncated cone body surface. The overall gross weight of the raise boring head is reduced and the strength-to-weight ratio is increased. The structural rigidity of the raise boring head is improved even though many of the structural components used in prior art raise boring heads have been eliminated.

Self-cleaning raise boring head system

A raise boring system is provided for boring raise holes wherein the finished raise holes have portions of different diameters. The system includes a raise head with a central drive stem defining an axis of rotation. Primary cutter means are positioned on the raise head for disintegrating the earth formations out to a first radial distance from said axis of rotation. Expanding secondary cutter means are positioned on the raise head for selectively disintegrating earth formations from said first radial distance out to additional and greater radial distances from said axis of rotation. The expanding secondary cutter means may be selectively located in a first position either beneath or in the same plane as the primary cutter means during boring at said first radial distance from said axis of rotation and selectively located in additional positions for boring at greater radial distances from said axis of rotation. Expansion means are provided for moving said expanding secondary cutter means to said additional positions during the boring operation.

System for boring raises having portions of different diameters

An insert cutter for earth boring includes a plurality of skewed inserts for contacting the earth formations being bored. At least one annular row of tungsten carbide inserts are positioned in the cutter body. Each insert has an elongated body and a formation contacting head. The elongated body is mounted in a socket in the cutter body and the formation contacting head projects from the cutter body. The inserts are installed on the cutter body such that the inserts axes are angularly offset between one-half to thirty degrees from the rotational axis of the cutter.

Skewed inserts for an earth boring cutter

The rolling cutter or stabilizer member of a rotary drill string unit is effectively locked in place by a locking device. The device allows the cutter or stabilizer member to carry radial, tangential and axial loads. A support member includes a surface positioned perpendicular to the resultant of the expected radial load and tangential load. A support shaft includes a slabbed-off surface positioned perpendicular to the resultant of said resultant loads and said axial load.

Locking apparatus for earth boring cutter or stabilizer

A raise bit for enlarging a pilot hole into a larger diameter hole by disintegrating the earth formations that surround the pilot hole is provided with a removable drive stem. The removable drive stem allows the raise bit to be transported through small passages and helps extend the useful lifetime of the bit. The bit may be assembled without weakening the highly-stressed, heat-treated stem by welding. The raise bit body includes a multiplicity of rolling cutters for contacting and disintegrating the earth formations surrounding the pilot hole. A central opening extends through the bit body. The central opening includes an upward facing tapered surface. The lower end of the drive stem extends through the central opening. A downward facing tapered surface on the drive stem mates with the upward facing tapered surface on the bit body. The lower end of the drive stem is threaded to receive a threaded nut which draws the tapered surfaces together.

Growing community of inventors

Duncanville, TX, United States of America

Howard E Mitchell