Earth-boring drill bits

Claim 2

An earth-boring bit comprising a metallic shank, having a tubular bore, one end of said shank coated with a hard material bonded to said end and forming a face of said bit, circumambient steps extending across the face of said bit from the central portion of the bit to adjacent the gage of the bit, said steps including a rise and a land, sockets in said hard material of said face positioned between a rise and a land of said steps, preform cutters mounted in said sockets in a plurality of longitudinal arrays spaced from each other about said face, each of said cutters including a plurality of abrasive particles bonded into a preform, said preform cutters formed with a cutting face and back.

Claim 3

The bit of claim 1, a number of said sockets being positioned between said rise and land of said steps.

Claim 4

The bit of claim 1, diamonds positioned at the central portion and the gage of the bit.

Claim 5

The bit of claim 1, means on said studs and sockets to position the faces of the preforms substantially in the same angular direction.

Claim 6

The bit of claim 1, said preforms being of shape to fit into said sockets with the back of said cutters supported by said sockets in thrust transfer relation to said face of said bit at said steps, the cutting faces of the cutters in all of the arrays facing in the same angular direction.

Claim 7

The bit of claim 5, diamonds positioned at the central portion of said bit and at the gage of said bit.

Claim 8

The bit of claim 5, said steps extending in substantially spiral formation from adjacent the central portion of the bit to adjacent the gage of said bit and the said cutters extending in said arrays in substantially spiral formation across the face of the bit.

Claim 9

The bit of claim 7, diamonds positioned at the central portion of the bit and at the gage of the bit.

Claim 10

An earth-boring bit comprising a metallic shank, having a tubular bore, one end of said shank coated with a hard material bonded to said end and forming a face of said bit, steps including a rise and a land extending in a substantially spiral formation from adjacent the central portion of said bit to adjacent the gage of the bit, sockets in said hard material of said face positioned at a rise and a land of said steps, preform cutters mounted in said sockets in a plurality of longitudinal arrays spaced from each other about said face, each of said cutters including a plurality of abrasive particles bonded into a preform, said preform cutters formed with a cutting face and back.

Claim 11

An earth-boring bit comprising a metallic shank, having a tubular bore, one end of said shank coated with a hard material bonded to said end and forming a face of said bit, steps including a rise and a land extending in a substantially spiral formation from adjacent the central portion of said bit to adjacent the gage of the bit, sockets in said hard material of said face positioned at a rise and a land of said steps, preform cutters mounted in said sockets in a plurality of longitudinal arrays spaced from each other about said face, each of said cutters including a plurality of abrasive particles bonded into a preform, said preform cutters formed with a cutting face and back.

Claim 12

The bit of claim 9, diamonds positioned at the central portion of said bit and at the gage of said bit.

Claim 13

The bit of claim 9, a number of said sockets being positioned between said rise and land of said steps.

Claim 14

The bit of claim 9, diamonds positioned at the central portion and the gage of the bit.

Claim 15

The bit of claim 9, means on said studs and sockets to position the faces of the preforms substantially in the same angular direction.

Claim 16

The bit of claim 9, said preforms being of shape to fit into said sockets with the back of said cutters supported by said sockets in thrust transfer relation to said face of said bit at said steps, the cutting faces of the cutters in all of the arrays facing in the same angular direction.

Claim 17

The bit of claim 14, diamonds positioned at the central portion of said bit and at the gage of said bit.

Claim 18

The bit of claim 14, said steps extending in substantially spiral formation from adjacent the central portion of the bit to adjacent the gage of said bit and the said cutters extending in said arrays in substantially spiral formation across the face of the bit.

Claim 19

The bit of claim 16, diamonds positioned at the central portion of the bit and at the gage of the bit.

Claim 20

An earth-boring drill bit comprising a metallic shank having a tubular bore, one end of said shank coated with a hard material bonded to said end and forming a face of said bit, steps extending circumambiently in said face from adjacent the central portion of said bit to adjacent the gage of said bit, said steps including a rise and a land, sockets positioned between a land and a rise of said steps, studs in said sockets, said studs carrying receptacles, preformed cutters positioned in said receptacles, said studs and cutters being arranged in longitudinal arrays spaced from each other and extending across the face of said bit, in staggered overlapping relation to the cutters in adjacent arrays, said cutters having a cutting face and a back, the back of said cutter supported in said receptacle in thrust transfer relation to said face of said bit at said steps, the cutting faces of said cutters in all of the arrays facing in the same angular direction.

Claim 21

An earth-boring drill bit comprising a metallic shank having a tubular bore, one end of said shank coated with a hard material bonded to said end and forming a face of said bit, steps extending circumambiently in said face from adjacent the central portion of said bit to adjacent the gage of said bit, said steps including a rise and a land, sockets positioned between a land and a rise of said steps, studs in said sockets, said studs carrying receptacles, preformed cutters positioned in said receptacles, said studs and cutters being arranged in longitudinal arrays spaced from each other and extending across the face of said bit, in staggered overlapping relation to the cutters in adjacent arrays, said cutters having a cutting face and a back, the back of said cutter supported in said receptacle in thrust transfer relation to said face of said bit at said steps, the cutting faces of said cutters in all of the arrays facing in the same angular direction.

Claim 22

The bit of claim 18, a number of said sockets being positioned at the apex between said lands and rise of said steps.

Claim 23

The bit of claim 18, diamonds positioned at the central portion of said bit and at the gage of said bit.

Claim 24

The bit of claim 18, said steps extending in spiral formation from adjacent the central portion of said bit to adjacent the gage of the bit.

Claim 25

The bit of claim 21, diamonds positioned at the central portion of said bit and at the gage of said bit.

Claim 26

The earth-boring drill bit of claim 18, a plurality of fluid channels positioned in said face and extending to the gage of said bit, said fluid channels communicating with the said tubular bore.

Claim 27

The bit of claim 23, diamonds positioned at the central portion of said bit and at the gage of said bit.

Claim 28

An earth-boring drill bit comprising a metallic shank having a tubular bore, one end of said shank coated with a hard material bonded to said end and forming a face of said bit, steps extending in substantially spiral formation in said face from adjacent the central portion of said bit to adjacent the gage of said bit, said steps including a rise and a land, cutters positioned in a substantially spiral formation from the adjacent central portion of said bit to adjacent the gage of said bit, sockets positioned between a land and a rise of said steps, studs in said sockets, said studs carrying receptacles, preformed cutters positioned in said receptacles, said studs and cutters being arranged in longitudinal arrays spaced from each other and extending across the face of said bit, in staggered overlapping relation to the cutters in adjacent arrays, said cutters having a cutting face and a back, the back of said cutter supported in said receptacle in thrust transfer relation to said face of said bit at said steps, the cutting faces of said cutters in all of the arrays facing in the same angular direction.

Claim 29

An earth-boring drill bit comprising a metallic shank having a tubular bore, one end of said shank coated with a hard material bonded to said end and forming a face of said bit, steps extending in substantially spiral formation in said face from adjacent the central portion of said bit to adjacent the gage of said bit, said steps including a rise and a land, cutters positioned in a substantially spiral formation from the adjacent central portion of said bit to adjacent the gage of said bit, sockets positioned between a land and a rise of said steps, studs in said sockets, said studs carrying receptacles, preformed cutters positioned in said receptacles, said studs and cutters being arranged in longitudinal arrays spaced from each other and extending across the face of said bit, in staggered overlapping relation to the cutters in adjacent arrays, said cutters having a cutting face and a back, the back of said cutter supported in said receptacle in thrust transfer relation to said face of said bit at said steps, the cutting faces of said cutters in all of the arrays facing in the same angular direction.

Claim 30

The bit of claim 25, diamonds at the central portion of said bit and at the gage of said bit.

Claim 31

The bit of claim 25, a number of said sockets being positioned at the apex between said lands and rise of said steps.

Claim 32

The bit of claim 25, diamonds positioned at the central portion of said bit and at the gage of said bit.

Claim 33

The bit of claim 25, said preforms extending in spiral formation from adjacent the central portion of said bit to adjacent the gage of the bit.

Claim 34

The bit of claim 29, diamonds positioned at the central portion of said bit and at the gage of said bit.

Claim 35

The earth-boring drill bit of claim 25, a plurality of fluid channels positioned in said face and extending to the gage of said bit, said fluid channels communicating with the said tubular bore.

Claim 36

The bit of claim 31, diamonds positioned at the central portion of said bit and at the gage of said bit.