Method for the manufacturing of a cone cutter for rotary drilling by crushing, a rotary cone drill bit, a cone cutter and crushing elements therefor

Abstract

A rotary cone drill bit includes at least one leg carrying a journal provided with bearing surfaces cooperating via bearing elements with bearing races in a rotatable cone cutter. The cone cutter is provided with rows of crushing elements. Each crushing element has a greatest width (D) and a greatest height (H), wherein HID<1.2. The crushing elements are welded to the body of the cone cutter to form a metallurgical bond therewith.

What is claimed is:  
     
         1 . A rotary cutting head for cutting rock by crushing, comprising: 
 a support;    a cone cutter rotatably mounted by bearings on the support;    rows of welded-on crushing elements adhered to a base body of the cone cutter by a metallurgical bond, each crushing element comprising a body having a working portion, an opposing mounting portion, and an intermediate portion from which the working and mounting portions extend, each crushing element having a greatest width D at the intermediate portion, and a greatest height H extending from a tip of the working portion to a transition between the intermediate portion and the mounting portion, wherein HID<1.2.    
     
     
         2 . The cutting head according to  claim 1  wherein the cutting head comprises a drill bit having a plurality of the supports, the supports comprising legs.  
     
     
         3 . A crushing element adapted for use on a rotary cone cutter, the crushing element comprising a cemented carbide body having a top working portion, an opposing bottom mounting portion of generally conical shape, and an intermediate portion from which the mounting portion extends, the crushing element having a greatest width D at the intermediate portion, and a greatest height H extending from a tip of the mounting portion to a transition between the intermediate portion and the mounting portion, wherein H/D<1.2.  
     
     
         4 . The crushing element according to  claim 3  wherein the mounting portion includes a spigot extending downwardly from a center of a bottom of a conical section of the mounting portion, the spigot extending symmetrically about a central axis of the crushing element.  
     
     
         5 . The crushing element according to  claim 3  wherein the mounting portion forms an internal cone angle from 150° to less than 180°.  
     
     
         6 . The crushing element according to  claim 3  wherein the intermediate portion has a height no greater than 15 mm.  
     
     
         7 . A rotary cone cutter adapted to be rotatably mounted on a rotary cutting head, the cone cutter comprising a base body, and rows of welded-on crushing elements adhered to the base body by metallurgical bonds, each crushing element comprising a body having a working portion, an opposing mounting portion, and an intermediate portion from which the working mounting portions extend, each crushing element having a greatest width D at the intermediate portion, and a greatest height H extending from a tip of the working portion to a transition between the intermediate portion and the mounting portion, wherein H/D<1.2.  
     
     
         8 . A method of manufacturing a rotary rock-crushing cone cutter comprising the steps of: 
 A) providing a base body, and a plurality of crushing elements, each crushing element comprising a body having a working portion, an opposing mounting portion, and an intermediate portion from which the working and mounting portions extend, each crushing element having a greatest width D at the intermediate portion, and a greatest height H extending from a tip of the working portion to a transition between the intermediate portion and the mounting portion, wherein H/D<1.2;    B) connecting the base body to one pole of an electric circuit, and connecting one of the crushing elements to another pole of the circuit;    C) bringing a surface of the mounting portion of the crushing element toward a supporting surface of the base body and energizing the circuit to create an electric arc between the mounting portion and the supporting surface;    D) maintaining the arc sufficiently to melt both the surface of the mounting portion and the supporting surface;    E) pressing the melted surfaces together;    F) permitting the pressed-together melted surfaces to solidify; and    G) repeating steps B-F for the remaining crushing elements.    
     
     
         9 . The method according to  claim 8  wherein the electric circuit is energized by a capacitor pack in step C, the mounting portion including a spigot projecting downwardly from a center of a bottom of a conical segment of the mounting portion, step C comprising bringing the spigot into contact with the supporting surface to short-circuit the capacitor pack.  
     
     
         10 . The method according to  claim 8  wherein step C comprises contacting the mounting portion with the supporting surface and then energizing the circuit while simultaneously lifting the mounting portion off the supporting surface to form the electric arc.