Diamond drill bit with hemispherically shaped diamond inserts

Claim 2

A rotary drill bit for drilling a hole in subterranean formations comprising: a body portion including a matrix forming a face of said bit; means to define fluid passageways across said matrix, said means dividing said matrix into a plurality of fins; and a plurality of hemispherically shaped diamond cutting elements embedded in each of said fins, each element having a cleaved, planar face, a portion of the planar face of each of said cutting elements which is not embedded in each fin being disposed to define a cutting surface to successively drill the formation upon rotation of the bit.

Claim 3

A rotary drill bit as defined in claim 1 wherein the diamond cutting elements are disposed such that an edge adjacent the planar face of the hemispherical cutting elements grooves into the formation.

Claim 4

A rotary drill bit as defined in claim 1 wherein the diamond cutting elements are positioned in said bit such that they have a leading edge in the direction of rotation of said bit and an outer edge distal from said matrix, and wherein the leading edge is inclined downward at a first angle α from a plane normal to the face of said bit and parallel to the direction of rotation and wherein the outer edge is inclined downward at a second angle β from a plane normal to the face of said bit and parallel to the intersection of the planar face of the diamond element with the face of said bit.

Claim 5

A rotary drill bit as defined in claim 3 wherein said first angle α is from about 30 to about 60 degrees.

Claim 6

A rotary drill bit as defined in claim 3 wherein said first angle α is about 45 degrees.

Claim 7

A rotary drill bit as defined in claim 4 wherein said second angle β is from about 15 to about 30 degrees.

Claim 8

A rotary drill bit as defined in claim 6 wherein said second angle β is about 30 degrees.

Claim 9

A rotary drill bit as defined in claim 3 wherein said first angle α is about 45 degrees and said second angle β is about 30 degrees.

Claim 10

A rotary drill bit as defined in claim 1 wherein the fins are configured so as to leave a core in the center of the bit.

Claim 11

A rotary drill bit as defined in claim 9 further comprising means for cutting away the core.

Claim 12

A rotary drill bit as defined in claim 10 wherein the means for cutting away the core comprises a disk shaped insert positioned within said bit, said insert including fluid passageways and a pair of hemispherically shaped diamond cutting elements.

Claim 13

A rotary drill bit as defined in claim 10 wherein the means for cutting away the core comprises a projection extending across the center of the bit, said projection including a pair of hemispherically shaped diamond cutting elements.

Claim 14

A rotary drill bit for drilling a hole in subterranean formations comprising: a body portion including a matrix forming a face of said bit; means to define fluid passageways across said matrix, said means dividing said matrix into a plurality of fins; a plurality of hemispherically shaped diamond cutting elements each having a cleaved planar face, said elements being embedded in each of said fins such that a portion of the planar face of each element is exposed, the elements being positioned such that they have a leading edge in the direction of rotation of the bit and an outer edge distal from said matrix, wherein the leading edge is inclined downward at a first angle α from a plane normal to the face of the bit and parallel to the direction of rotation and wherein the outer edge is inclined downward at a second angle β from a plane normal to the face of the bit and parallel to the intersection of the planar face of the diamond element with the face of the bit.

Claim 15

A rotary drill bit for drilling a hole in subterranean formations comprising: a body portion including a matrix forming a face of said bit; means to define fluid passageways across said matrix, said means dividing said matrix into a plurality of fins; a plurality of hemispherically shaped diamond cutting elements each having a cleaved planar face, said elements being embedded in each of said fins such that a portion of the planar face of each element is exposed, the elements being positioned such that they have a leading edge in the direction of rotation of the bit and an outer edge distal from said matrix, wherein the leading edge is inclined downward at a first angle α from a plane normal to the face of the bit and parallel to the direction of rotation and wherein the outer edge is inclined downward at a second angle β from a plane normal to the face of the bit and parallel to the intersection of the planar face of the diamond element with the face of the bit.

Claim 16

A rotary drill bit as defined in claim 13 wherein said first angle α is from about 30 to about 60 degrees.

Claim 17

A rotary drill bit as defined in claim 14 wherein said second angle β is from about 15 to about 30 degrees.

Claim 18

A rotary drill bit as defined in claim 13 wherein said first angle α is about 45 degrees and said second angle β is about 30 degrees.