Earth cutter assembly

Claim 2

An earth cutter assembly, for rotary boring of the face of earth formations, comprising: roller earth cutters, for distintegrating the earth formation face; a rotatable cutterhead having a rotary axis, for supporting said roller earth cutters; said cutterhead Having means for couplingly receiving a drive stem for imparting rotary drive to said cutterhead; and means mounting said roller earth cutters only to said cutterhead for rotation therewith; wherein said mounting means is cooperative with said roller earth cutters to cause said roller earth cutters effectively to define at least one, overall circular and convex cutting surface, about said axis, upon rotation of said cutterhead.

Claim 3

An earth cutter assembly, according to claim 1, wherein: said mounting means is cooperative with said roller earth cutters to cause said earth cutters effectively to define said cutting surface with at least one, overall circular and flat cutting portion about said axis, upon rotation of said cutterhead.

Claim 4

An earth cutter assembly, according to claim 1, wherein: said convex cutting surface has a convexity which defines a symmetrical arc; and said arc of said surface, taken at any given place along the circular disposition of said surface, has a radius originating at a given point spaced radially from said axis.

Claim 5

An earth cutter assembly, according to claim 3, wherein: said given point occupies a location along an imaginary circle lying concentric with said axis.

Claim 6

An earth cutter assembly, according to claim 3, wherein: said earth cutters comprise a plurality of earth face cutters; and each earth face cutter of said plurality has a cutting surface which defines a complement of said symmetrical arc.

Claim 7

An earth cutter assembly, according to claim 1, wherein: said mounting means comprises means which replaceably fixes said earth cutters of said plurality upon a surface of said cutterhead in a predetermined pattern which insures an engagement of substantially all of said earth formation face by said earth cutters upon rotation of said cutterhead.

Claim 8

An earth cutter assembly, according to claim 6, wherein: said plurality of earth cutters comprises a first set of earth cutters and a second set of earth cutters; and all earth cutters of one of said first and second sets are of common overall dimensions, are selectively interchangeable, any one thereof with any other thereof with respect to said pattern, and are cooperative, with the earth cutters of the other of said first and second sets, in any selectively interchanged position, to maintain definition of said overall circular and convex cutting surface.

Claim 9

An earth cutter assembly, according to claim 6, wherein: said pattern defines a space in the axial center of said cutterhead which is devoid of earth cutters; and said drive stem receiving means is located in said axial center for fixedly engaging a drive stem.

Claim 10

An earth cutter assembly, according to claim 8, wherein: said drive stem receiving means comprises a borehole formed in said cutterhead for receiving a drive stem therewithin.

Claim 11

An earth cutter assembly, according to claim 6, wherein: said earth cutters of said plurality comprise roller cutters having rotary axes; said roller cutters are all replaceably fixed upon said cutterhead surface by said mounting means only.

Claim 12

An earth cutter assembly, according to claim 10, wherein: said mounting means comprise shaft members each of which carries one of said roller cutters rotatable thereon; said shaft members for respective roller cutters, are variously longitudinally disposed, relative to said axis, from a plane perpendicular to said axis to a plane inclined at least 45 1/2 * to the horizontal.

Claim 13

An earth cutter assembly, according to claim 10, wherein: said roller cutters each have a plurality of earth-cutter elements circumferentially carried thereabout; said elements being effective, with rotation of said body, to define concentric rows of earth cutters about said rotary axis of said body; and given ones of said elements of certain roller cutters track in, and cooperate to define rows in which other said elements of Other roller cutters track.

Claim 14

A roller earth face cutter, for use with others thereof in a patterned array on a rotatable cutterhead for cooperative, rotary boring of the face of an earth formation to form at least one, overall circular and concave cut in said face; comprising: a roller cutter body having a rotary axis and an earth face engaging surface; said body further having relieved areas formed therewithin for receiving supporting means, for mounting said body on a rotatable cutterhead together with other roller earth face cutters; and said body further having earth cutting means disposed about its earth-face-engaging surface; said earth cutting means comprise means effective for cutting an arcuate kerf, in the face of the formation, which kerf defines a complementary portion of said one overall circular and concave cut.

Claim 15

A roller earth face cutter, for use with others thereof in a patterned array on a rotatable cutterhead for cooperative, rotary boring of the face of an earth formation to form at least one, overall circular and concave cut in said face; comprising: a roller cutter body having a rotary axis and an earth face engaging surface; said body further having relieved areas formed therewithin for receiving supporting means, for mounting said body on a rotatable cutterhead together with other roller earth face cutters; and said body further having earth cutting means disposed about its earth-face-engaging surface; said earth cutting means comprise means effective for cutting an arcuate kerf, in the face of the formation, which kerf defines a complementary portion of said one overall circular and concave cut.

Claim 16

A roller earth face cutter, for use with others thereof in a patterned array on a rotatable cutterhead for cooperative, rotary boring of the face of an earth formation to form at least one, overall circular and concave cut in said face; comprising: a roller cutter body having a rotary axis and an earth face engaging surface; said body further having relieved areas formed therewithin for receiving supporting means, for mounting said body on a rotatable cutterhead together with other roller earth face cutters; and said body further having earth cutting means disposed about its earth-face-engaging surface; said earth cutting means comprise means effective for cutting an arcuate kerf, in the face of the formation, which kerf defines a complementary portion of said one overall circular and concave cut; wherein said body has a plurality of rows of drill holes formed in said earth face engaging surface; said body further has a first portion of uniform outside diameter extending from one axial end of said body to an intermediate area of said body, and at least a second, substantially conical portion, extending from the opposite axial end of said body to an intermediate area of said body; at least one row of drill holes of said plurality thereof is formed in said first portion; at least one other row of drill holes of said plurality thereof is formed in said second portion; said earth cutting means comprise earth cutter inserts fixed in said drill holes; said inserts are all of uniform length, and have earth-cutting working ends and non-working ends opposite thereto; and said non-working ends of all said inserts are bottomed in said drill holes, and said working ends, from row to row, project diverse radial distances from said axis.

Claim 17

A roller earth face cutter, for use with others thereof in a patterned array on a rotatable cutterhead for cooperative, rotary boring of the face of an earth formation to form at least one, overall circular and concave cut in said face; comprising: a roller cutter body having a rotary axis and an earth face engaging surface; said body further having relieved areas formed therewithin for receiving supporting means, for mounting said body on a rotatable cutterhead together with other roller earth face cutters; and said body further having earth cutting means disposed about its earth-face-engaging surface; said earth cutting means comprise means effective for cutting an arcuate kerf, in the face of the formation, which kerf defines a complementary portion of said one overall circular and concave cut; wherein said body has a plurality of rows of drill holes formed in said earth face engaging surface; said body further has a first portion of uniform outside diameter extending from one axial end of said body to an intermediate area of said body, and at least a second, substantially conical portion, extending from the opposite axial end of said body to an intermediate area of said body; at least one row of drill holes of said plurality thereof is formed in said first portion; at least one other row of drill holes of said plurality thereof is formed in said second portion; said earth cutting means comprise earth cutter inserts fixed in said drill holes; said inserts are all of uniform length, and have earth-cutting working ends and non-working ends opposite thereto; and said non-working ends of all said inserts are bottomed in said drill holes, and said working ends, from row to row, project diverse radial distances from said axis.

Claim 18

An earth face cutter, according to claim 14, wherein: said body has at least three rows of drill holes formed in said outer surface; all drill holes of at least one row of said three rows thereof are perpendicular to said axis; and all drill holes of at least another row of said three rows thereof are obliquely disposed relative to said axis.

Claim 19

An earth cutter assembly, for rotary boring of the face of earth formations, comprising: roller earth cutters, for distintegrating the earth formation face: a rotatable cutterhead having a rotary axis, for supporting said roller earth cutters; said cutterhead having means for couplingly receiving a drive stem for imparting rotary drive to said cutterhead; and means mounting said roller earth cutters only to said cutterhead for rotation therewith; wherein said mounting means is cooperative with said roller earth cutters to cause said roller earth cutters effectively to define a cutting surface, about said axis, upon rotation of said cutterhead, which surface has two, overall circular and convex portions.

Claim 20

An earth cutter assembly, for rotary boring of the face of earth formations, comprising: roller earth cutters, for distintegrating the earth formation face: a rotatable cutterhead having a rotary axis, for supporting said roller earth cutters; said cutterhead having means for couplingly receiving a drive stem for imparting rotary drive to said cutterhead; and means mounting said roller earth cutters only to said cutterhead for rotation therewith; wherein said mounting means is cooperative with said roller earth cutters to cause said roller earth cutters effectively to define a cutting surface, about said axis, upon rotation of said cutterhead, which surface has two, overall circular and convex portions.

Claim 21

An earth cutter assembly, according to claim 16, wherein: said two convex portions each have a convexity which defines a symmetrical arc; and said arcs, taken at any given place along the circular disposition of said portions, have a radius originating at given points spaced radially from said axis.

Claim 22

An earth cutter assembly, according to claim 17, wherein: said given points are spaced apart and are perpendicularly in line relative to said axis.

Claim 23

An earth cutter assembly, according to claim 17, wherein: said given points are spaced apart and are obliquely in line relative to said axis.

Claim 24

An earth cutter assembly, for rotary boring of the face of earth formations, comprising: roller earth cutters, for distintegrating the earth formation face; a rotatable cutterhead having a rotary axis, for supporting said roller earth cutters; said cutterhead having means for couplingly receiving a drive stem for imparting rotary drive to said cutterhead; and means mounting said roller earth cutters only to said cutterhead for rotation therewith; wherein said mounting means is cooperative with said roller earth cutters to cause said roller earth cutters effectively to define a cutting surface about said axis, upon rotation of said cutterhead, which surface has at least one, overall circular and convex portion, and at least one, overall circular and concave portion.

Claim 25

An earth cutter assembly, for rotary boring of the face of earth formations, comprising: roller earth cutters, for distintegrating the earth formation face; a rotatable cutterhead having a rotary axis, for supporting said roller earth cutters; said cutterhead having means for couplingly receiving a drive stem for imparting rotary drive to said cutterhead; and means mounting said roller earth cutters only to said cutterhead for rotation therewith; wherein said mounting means is cooperative with said roller earth cutters to cause said roller earth cutters effectively to define a cutting surface about said axis, upon rotation of said cutterhead, which surface has at least one, overall circular and convex portion, and at least one, overall circular and concave portion.

Claim 26

An earth cutter assembly, according to claim 18, wherein: said mounting means is cooperative with said roller earth cutters to cause said roller earth cutters effectively to define said cutting surface with at least one, overall circular and flat cutting portion, contiguous with at least one of said two convex portions and concentric with said axis, upon rotation of said cutterhead.