Drill bits for drilling while driving foundation components

Abstract

Drill bits are provided for a drilling while driving machine. In some cases, the drill bit is a multi-stage bit capable of selectively cutting at two different diameters. In others, the bit is an expanding bit that can be passed through a foundation component while its being driven. The bit has a pair of cutting wings that can move between a retracted orientation where the bit's diameter is narrower than the inner diameter of the driven component, to a splayed orientation where the diameter is equal to or larger than the driven component's outside diameter.

1 . A two-stage drill bit for a drilling while driving a foundation component comprising:
 an elongated body portion;   a first cutting portion at a leading edge of the elongated body portion;   at least one second cutting portion along a length of the body portion away from the leading edge, the at least one second cutting portion movable from a first passive orientation to a second active orientation when the drill bit is extended out of a leading edge of the foundation component sufficiently far for the at least one second cutting portion to clear the leading edge, the at least one second cutting portion cutting a wider diameter bore than the first cutting portion.   
     
     
         2 . The drill bit according to  claim 1 , further comprising a plunger portion in the elongated body that causes the at least one second cutting portion to splay out to the second active orientation when it has cleared the leading edge. 
     
     
         3 . The drill bit according to  claim 2 , wherein the plunger portion engages at least one piston that engages the at least one second cutting portion. 
     
     
         4 . The drill bit according to  claim 2 , wherein the plunger portion is connected to a drill rod. 
     
     
         5 . The drill bit according to  claim 1 , wherein the first cutting portion is a drag bit. 
     
     
         6 . The drill bit according to  claim 1 , wherein the first cutting portion is a button bit. 
     
     
         7 . A system for driving a foundation component with drill assist comprising:
 a rotary driver operable to travel along a machine mast and to impart rotational torque and downforce to the head of the foundation component to drive it into underlying ground;   a drilling tool positioned on the mast above the rotary driver and extending a drill rod through the rotary driver and the foundation component;   a drill bit attached to the end of the drill rod, the drilling tool operable to actuate the drill bit through the foundation component during driving; and   an automated controller controlling operation of the rotary driver and drilling tool, wherein the controller is programmed to cause the drilling tool to partially extend the drill bit out of an open lower end of the foundation component, to monitor at least one performance metric of either the rotary driver or drilling tool while actuating the drill bit through the rotary drive, and to cause the drilling tool, to extend the drill bit further out of the foundation component in response to a change in the at least one performance metric.   
     
     
         8 . The system according to  claim 7 , wherein the at least one performance metric is selected from the group consisting of hydraulic pressure supplied to the drill tool, a rate of penetration of the foundation component, a torque at an output of the drill tool, and a torque at an output of the rotary driver. 
     
     
         9 . A method of performing a drilling while driving operation to drive a foundation component into underlying ground, the method comprising:
 applying torque and downforce to a first end of the structural member to drive it into underlying ground with a rotary driver;   applying torque and downforce to a drill bit extending partially through the foundation component via a drill shaft connected to a drilling tool to enable a first cutting surface at a leading end of the drill bit to drill ahead of a leading end of the structural member, the first cutting surface having a first drilling diameter;   monitoring at least one performance metric of the operation with an automated controller; and   in response to a detected change in the at least one performance metric, extending the drill bit further through the foundation component to enable a second cutting surface along a length of the drill bit to exit the foundation component, the second cutting surface having a second drilling diameter larger than the first drilling diameter.   
     
     
         10 . The method according to  claim 9 , wherein the at least one performance metric is selected from the group consisting of hydraulic pressure supplied to the drill tool, a rate of penetration of the foundation component, torque at an output of the rotary driver, and torque at an output of the drill tool. 
     
     
         11 . A drill bit for drilling while driving comprising:
 a body portion;   a pair of cutting wings hingedly attached to a cutting end of the body portion; and   a spring retained within the body portion, wherein the spring is segmented into two independently movable portions that are oppositely deformed by respective ones of the cuttings wings when the wings are compressed inward towards the body portion.   
     
     
         12 . The drill bit according to  claim 11 , wherein each cutting wing includes an angled lower contact surface that causes the wings to expand away from the body portion when pressed against a resisting medium. 
     
     
         13 . The drill bit according to  claim 12 , wherein each cutting wing comprises an upper contact surface that engages a lower edge of the body portion when the cutting wings are fully expanded. 
     
     
         14 . The drill bit according to  claim 11 , further comprising a spring retainer pressed into an air passage running through the body portion, the spring retainer having a slot that receives a portion of the wing spring. 
     
     
         15 . The drill bit according to  claim 14 , further comprising a hinge pin, passing through the pair of cutting wings and the main body, the hinge pin having a through hole for receiving the spring retainer. 
     
     
         16 . The drill bit according to  claim 14 , further comprising a set screw, passing through the main body, and engaging the hinge pin. 
     
     
         17 . The drill bit according to  claim 11 , wherein an outer surface of the body portion is fluted to provide a channel for ejection of drilling spoils.