Rotary tools or bits

Abstract

Rotary tools or bits carry cutter element including pointed contact structures and elements for chipping, cutting, and breaking non-ductile materials such as rock. The cutter elements directly contact and cut through rock and other materials and have tapered contact structure ends. Rotary tools or bits for carrying the cutter elements carry fixed cutter elements, or have sockets for removable threaded or rotatable cutter elements, arranged in straight or curved rows on the head opposite a drill-string-engaging base of the tool. The tools also have radially-extending buttresses which help to protect the cutter elements from damage as a drill string and bit are withdrawn from a bore.

I claim:  
     
         1 . A rotary earth boring bit comprising: 
 a rotatable body having a drill string attachment side, and    a bore-face and a bore wall side opposite the attachment side;    a plurality of cutting elements rigidly carried on the bore face and bore wall side of the bit in spaced apart relation, each such cutting element configured to cut a portion of a bore and a earth formation when the bit is in use;    each of the cutting elements has a concentric cutting tip structure surrounded by a symmetric tapered structure with an obtuse included angle;    a portion of the cutting elements are located on the bore wall side of the body having axes that are generally perpendicular to the bore wall;    an additional portion of the cutting elements are located on the bore face side of the bit with their axes aligned substantially parallel to the axis of the bit;    further cutting elements are positioned on the bore face with their axes positioned generally between being perpendicular to the bore wall and parallel to the axis to the bit;    the tip structure of each cutting element comprises of man-made material harder than 67 on the Rockwood C scale.    
     
     
         2 . The earth-boring bit of  claim 1 , wherein the tip-structure is a fine point.  
     
     
         3 . The earth-boring bit of  claim 1 , wherein the axis of each cutting element is angled between 1° and 37° from a perpendicular to the bore face surface of the bit body.  
     
     
         4 . The earth-boring bit of  claim 1 , wherein at least a radially inward portion of each tapered structure is generally symmetrical in at least four equally spaced directions from the axis of the tapered structure.  
     
     
         5 . The earth-boring bit of  claim 1 , wherein a portion of said tapered structures is generally conical.  
     
     
         6 . The earth-boring bit of  claim 1  wherein at least a portion of the tip structure is comprised of a material harder than 1864 on the Vickers scale.  
     
     
         7 . The earth-boring bit of  claim 1 , wherein at least a portion of said cutting elements are fabricated from one of a group of materials comprising diamond, a nitride of a metallic element, a carbide of a metallic element, an oxide of a metallic element carbide, a boride of at least one metallic element, a silicide of a metallic element, and carbon nitride.  
     
     
         8 . A rotatable earth-boring body for cutting the bore face and the bore wall comprising: 
 a drill string attachment side;    a bore-face side opposite the attachment side;    a plurality of cutting elements having a tapered screw mounting thread;    a plurality of sockets formed at spaced-apart positions from one another on the bore-face side of the body, each socket being formed to hold and removably retain a corresponding cutting element,    each of said cutting elements being rigidly carried in and by one of said sockets on the bore-face and bore wall side of the body to cut the bore-face and the bore-wall when the body is in use;    the axis of each of said plurality of sockets is generally normal to said bore-face at it respective position on the body;    the axis of at least one of said sockets is closer to being parallel to the body axis than being perpendicular to the body axis;    at least three of the sockets have axis that are closer to being perpendicular to a local portion of said bore-wall than to being parallel to said portion of the bore-wall;    each of said sockets comprises a tapered screw thread, said sockets are arranged in a plurality of radially extending rows and each socket in the row is positioned with a portion of each socket located behind a portion of an adjacent socket in the row in the direction of the cutting element rotation.    
     
     
         9 . A rotary self-sharpening earth-boring bit comprising: 
 a rotatable body having an axis of rotation, a drill string attachment side, a bore-face side opposite the attachment side along said axis;    a plurality of elongated cutting elements, each having an axis;    a plurality of sockets in said rotatable body, adapted to hold and retain said plurality of elongated cutting elements, each of said cutting elements comprises: 
 a cutting tip structure, a cutting tapered structure, and a mounting structure;  
 the axis of a portion of the cutting elements is more perpendicular than parallel to the bore face at its socket location;  
 the axis of at least one of said cutting elements is closer to being parallel to the bit axis;  
 the axis of at least one of said cutting elements is perpendicular to the bore wall; and,  
 each of said cutting elements is rotatable during use about its axis in each of said sockets.  
   
     
     
         10 . The earth-boring bit of  claim 9 , wherein said cutting elements are arranged in a plurality of radially extending rows and wherein each of a plurality of said cutting elements in a row are positioned with a portion of each cutting element located behind a portion of an adjacent cutting element in the direction of cutting element motion.  
     
     
         11 . The earth-boring bit of  claim 9 , wherein the axis of at least one cutting element is angled between 1° and 37° from a perpendicular to a corresponding local portion of said bore-face at its socket location.  
     
     
         12 . The earth-boring bit of  claim 9 , wherein a portion of each of said cutting elements is generally conical.  
     
     
         13 . The earth-boring bit of  claim 9 , wherein the included angle of at least a portion of said cutting tapered structure is obtuse.  
     
     
         14 . A self-sharpening, rotary earth-boring drag bit comprising: 
 a rotatable body having a drill string attachment side and a bore-face side opposite the attachment side;    a plurality of fixed axis cutting elements rigidly carried on the bore-face side of the bit and configured to cut a bore-face and a bore-wall when the bit is in use;    each cutting element comprises an outer surface defining a tip structure and a tapered structure, the outer surfaces of the tapered structures converging into the outer surfaces of the tip structure;    each of said cutting elements includes an internal body portion, one region of each of said internal body portion is present at each tip structure;    a cross sectional area of said internal body near said one region is substantially smaller than the largest cross sectional area of the tapered structure;    at least a portion of the tapered structure surface adjacent to the tip structure has an obtuse included angle;    at least a portion of each of said internal body portion has a hardness greater than 1864 on the Vickers scale;    at least a portion of the tapered structure is more than 300 points softer on the Vickers scale than the internal body portion; and    a region of each said internal body portion is generally normal to a corresponding local portion of said bore-face.    
     
     
         15 . The earth boring bit of  claim 14 , wherein at least a portion of the tapered structure is harder than 67 on the Rockwell C scale.  
     
     
         16 . The earth-boring bit of  claim 14  wherein at lease one of said tapered structures is generally conical.  
     
     
         17 . The earth-boring bit of  claim 14  wherein the included angle of an outward surface portion of each tapered structure is obtuse.  
     
     
         18 . The earth-boring bit of  claim 14  wherein each of said cutting elements is rotatable about its axis.  
     
     
         19 . The earth-boring bit of  claim 14  wherein a region of said internal body is generally perpendicular to said bore-wall.  
     
     
         20 . The earth-boring bit of  claim 14  wherein at least a portion of each of said cutting elements is fabricated from at least one of a group materials comprising diamond, a nitride of a metallic element, a carbide of a metallic element, an oxide of a metallic element carbide, a boride of at least one metallic element, a silicide of a metallic element and carbon nitride.