Large diameter bit for shallow angle holes

Claim 2

A bit for enlarging a small diameter hole into a large diameter hole by disintegrating the formations surrounding the small diameter hole, said bit to be connected to a rotary drill string that extends through the small diameter hole with the central axis of said bit aligned with the central axis of said rotary drill string, comprising: a main bit body having a diameter larger than the diameter of the small diameter hole, said main bit body having a central axis that establishes the central axis of said bit; means on the central axis of said main bit body for connecting said main bit body to the rotary drill string; rolling cutter means mounted on said main bit body with the axis of rotation of said rolling cutter means inclined to the central axis of said main bit body for contacting and disintegrating the earth formations surrounding the small diameter hole at a first distance from the bit central axis; and rolling stabilization means mounted on said main bit body with the axis of rotation of said rolling stabilization means substantially parallel to the central axis of said main bit body for contacting the formations at substantially said first distance from the bit central axis and supporting a portion of the weight of the bit and providing stabilization to said bit.

Claim 3

The bit of claim 1 wherein said rolling stabilization means include a multiplicity of individual rolling members mounted on said main bit body for contacting the formations at substantially said first distance from the bit central axis and supporting a portion of the weight of the bit and stabilizing the bit, the axis of rotation of said rolling members being substantially parallel to the central axis of said main bit body.

Claim 4

A bit for enlarging a shallow angle pilot hole into a large diameter hole by disintegrating portions of the formations surrounding the pilot hole, said bit to be connected to a rotary drill string that extends through the shallow angle pilot hole with the central axis of the rotary drill string being generally concentric with the central axis of the pilot hole, comprising: a central shaft with a central axis that forms a bit central axis; a connection on said central shaft for connecting said central shaft to the rotary drill string with the central axis of said central shaft aligned with the central axis of said rotary drill string; first rolling cutter means connected to said central shaft for contacting and disintegrating the formations surrounding the pilot hole at a first distance from the bit central axis, the axis of rotation of said first rolling cutter means inclined to the bit central axis; rolling stabilization means positioned below said first cutter means for contacting the formations at substantially said first distance from the bit central axis and supporting a portion of the weight of the bit and stabilizing the bit, the axis of rotation of said rolling stabilization means being substantially parallel to the bit central axis; and second rolling cutter means connected to said central shaft for contacting and disintegrating the formations surrounding the pilot hole at a second distance from the bit central axis, the axis of rotation of said second rolling cutter means inclined to the bit central axis.

Claim 5

A bit for enlarging a shallow angle pilot hole into a large diameter hole by disintegrating portions of the formations surrounding the pilot hole, said bit to be connected to a rotary drill string that extends through the shallow angle pilot hole with the central axis of the rotary drill string being generally concentric with the central axis of the pilot hole, comprising: a central shaft with a central axis that forms a bit central axis; a connection on said central shaft for connecting said central shaft to the rotary drill string with the central axis of said central shaft aligned with the central axis of said rotary drill string; first rolling cutter means connected to said central shaft for contacting and disintegrating the formations surrounding the pilot hole at a first distance from the bit central axis, the axis of rotation of said first rolling cutter means inclined to the bit central axis; rolling stabilization means positioned below said first cutter means for contacting the formations at substantially said first distance from the bit central axis and supporting a portion of the weight of the bit and stabilizing the bit, the axis of rotation of said rolling stabilization means being substantially parallel to the bit central axis; and second rolling cutter means connected to said central shaft for contacting and disintegrating the formations surrounding the pilot hole at a second distance from the bit central axis, the axis of rotation of said second rolling cutter means inclined to the bit central axis.

Claim 6

The bit of claim 3 wherein said rolling stabilization means include a multiplicity of individual rolling members mounted below said first rolling cutter means for contacting the formations at substantially said first distance from the bit central axis and stabilizing the bit and supporting a portion of the weight of the bit, the axis of rotation of said rolling members being substantially parallel to the bit central axis.

Claim 7

The bit of claim 6 including additional rolling stabilization means for stabilizing and supporting a portion of the weight of the bit, positioned below said second cutter means at substantially said second distance from the bit central axis, the axis of rotation of said additional rollIng stabilization means substantially parallel to the bit central axis.

Claim 8

The bit of claim 5 wherein said additional rolling stabilization means include a multiplicity of individual rolling members mounted below said second rolling cutter means for contacting the formations at substantially said second distance from the bit central axis and stabilizing the bit and supporting a portion of the weight of the bit, the axis of rotation of said rolling members being substantially parallel to the bit central axis.