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.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This claims priority to U.S. provisional patent application No. 62/971,843 filed on Feb. 2, 2020, and 62/966,964 filed on Jan. 28, 2020, the disclosures of which are hereby incorporated by reference in their entirety.

BACKGROUND

The applicant of this disclosure has developed a new foundation for supporting single-axis trackers, fixed-tilt arrays and other structures that provides a steel-saving alternative to conventional monopile foundations. Known commercially EARTH TRUSS, this foundation is formed from a pair of adjacent angled legs extending below and above ground that are joined together with an adapter, truss cap or bearing adapter to form a truss with the ground. Each leg is made of a screw anchor that is driven below ground and an upper leg section. The below ground portion of each leg, known as a screw anchor, is an elongated, hollow, open-ended tube with an external thread form at the lower end and driving coupler at the upper end. The driving coupler is engaged by the chuck of a rotary driver and also serves an adapter for attaching an upper leg section once the anchor is driven. Because the screw anchor is open at both ends, it is possible to actuate a drilling tool through the rotary driver and screw anchor while the anchor is being driven. This reduces the torque and downforce required on the head of the screw anchor and facilitates embedment in difficult soils. To perform this function, the applicant of this disclosure has developed a proprietary machine that utilizes a rotary driver and drilling tool concentrically oriented on a common mast.

The technique of drilling while casing, that inserting pipe into the ground at the same time that a borehole is drilled, is known in the resource exploration and extraction arts. This is often done when drilling holes to extract water, oil, and natural gas to speed up the process and prevent the bore hole from caving in. The technique involves drilling into the ground while incrementally adding sections of drill rod and lengths of pipe casing. Often times an expanding drill bit is used to create a large diameter bore hole than the diameter of the pipe used to case it. This insures that pipe can be installed and also provides space for the drill spoils outside of the well.

Although drilling while casing is roughly analogous to drilling while driving, there are some substantial differences. When drilling and casing, the bore is larger than the casing by design. Space around the casing pipe is desired and necessary to provide room for drill spoils to be displaced. Therefore, the only objective is to keep the drill moving so that the well can reach its desired depth and continue to be cased. The casing pipe is nothing more than a conduit to enable the extraction of pressurized fluid or gas. By contrast, screw anchors are structural and must resist large axial forces of tension and compression. They are drilled into the ground like a screw into wood with positive engagement between the external threads and surround earth. Therefore, to the extent drilling is performed in-situ while driving, the drilled bore hole diameter must be kept as small as possible at all times, to prevent over-boring or augering the hole. That said, some soils are more difficult to embed in than others and therefore, a one-size fits all approach to drilling while driving will not work.

In recognition of these problems, various embodiments of this disclosure provide drill bits specifically adapted to drilling while driving, and control systems for a drilling machine that enables optimum use of such bits to facilitate driving embedment without over boring the ground.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A shows a screw anchor according to various embodiments of the invention;

FIG. 1B shows a drill rod according to various embodiments of the invention;

FIG. 2 shows a portion of a drilling while driving operation according to various embodiments of the invention;

FIG. 3 shows a portion of a mast of an automated machine for performing a drilling while driving operation according to various embodiments of the invention;

FIGS. 4A and 4B show front views of a two-stage drill bit usable in a drilling while driving operation in accordance with various embodiments of the invention;

FIGS. 5A and 5B are partially exploded views of the two-stage drill bit shown in FIGS. 4A and 4B.

FIG. 6 is a system diagram showing components of a system for performing an automated drilling while driving operations according to various embodiments of the invention;

FIG. 7 is a flow chart detailing the steps of a method for performing a drilling while driving operation according to various embodiments of the invention;

FIGS. 8A, 8B and 8C show different views of an expanding drill bit for use with a drilling while driving operation according to various embodiments of the invention;

FIG. 9A is an exploded view of the expanding drill bit shown in FIGS. 8A-8C;

FIG. 9B shows internal components of the expanding drill bit shown in FIGS. 8A-8C;

FIGS. 10A, 10B and 10C show cuttings wings of the drilling of FIGS. 8A-8C in various stages of deployment;

FIGS. 11A and 11B show internal spring components of the drill bit of FIGS. 8A-8C when the spring is relaxed and tensioned respectively; and

FIG. 12 shows a drilling while driving operation according to various embodiments of the invention.

DETAILED DESCRIPTION

The following description is intended to convey a thorough understanding of the embodiments described by providing a number of specific embodiments and details involving A-frame foundations used to support single-axis solar trackers. It should be appreciated, however, that the present invention is not limited to these specific embodiments and details, which are exemplary only. It is further understood that one possessing ordinary skill in the art in light of known systems and methods, would appreciate the use of the invention for its intended purpose.

FIG. 1A is a perspective view of screw anchor foundation component 10 of the EARTH TRUSS system. Screw anchor 10 is the base component that forms the below-ground portion of the system. As shown, screw anchor 10 consists of an elongated section of hollow steel pipe with external thread form 12 beginning at the lower end and driving coupler 15 at the upper end. The anchor is open at both ends and is driven into the ground with a combination of rotation and downforce translated to driving coupler 15 from a rotary driver on the mast of anchor driving machine with the threaded end leading. The feed and speed of the rotary driver are controlled so that the thread form 12 engages the soil as the anchor is screwed in without augering it.

As discussed in the background, in order to avoid having to drill in a separate step, screw anchor installation is assisted with a drilling tool that is attached to the same mast as the rotary driver. A long drill rod with an Earth or rock drill bit is extended through the rotary driver and screw anchor until the bit at the end emerges. FIG. 1B shows such a drill or tool shaft or rod 30 with bit 50 attached to the leading end. The opposing end is attached to a hydraulic drifter (not shown) or other suitable drilling tool. The specific dimensions of tool shaft 30 will depend on the length of the screw anchor being installed as well as the size of the machine. Though not show in FIG. 1B, the shaft may have a channel formed through the center to allow compressed air from an above-ground compressor on the driving machine to be passed through the shaft and vented out of the bit to blow drilling spoils out of the path of the drill bit as well as assist drilling.

Because anchor 10 is open at both ends, it is possible to actuate drill shaft 30 through it while a rotary driver is driving the screw anchor into the ground, enabling the drill bit to bore an opening ahead of the anchor. This is shown, for example, in FIG. 2. FIG. 2 shows portion of screw anchor 10 being installed with drill assist. As anchor 10 is driven into the underlying ground, with a combination of torque and downforce, drill rod 30 extended through it so as to extend bit 50 out of the open lower end. Bit 50 cuts a pilot bore ahead of screw anchor 10. Typically, when drilling through soil, this is accomplished with a combination of rotation and downforce. In the case of rock drilling, the primary mechanism is pulverization rather than cutting so in that case, the drill tool imparts, torque, downforce and hammering to the shaft and bit. By contrast, hammering is not productive when using a drag bit.

FIG. 3 shows a portion of mast 100 for a machine for performing a screw anchor driving operation such as that shown in FIG. 2. Thought not shown in FIG. 3, in various embodiments, mast 100 is attached to a piece of heavy equipment, such as a tracked, diesel powered base with a hydraulic power system and one or more articulating arms supporting mast 100 to enable the mast to be oriented to precise pitch, roll, yaw, X-direction, Y-direction and Z-direction orientations relative to the machine for driving screw anchors. Although FIG. 3 shows only a portion of mast 100, in real world applications, it may extend as long as 20-feet or more. Additional details of the machine mast are intentionally omitted here but may be found in commonly assigned U.S. patent application Ser. No. 16/416,022, now issued U.S. patent Ser. No. 10/697,490, the disclosure of which is hereby incorporated by reference in its entirety.

As shown, there are two carriages 110/120 that ride along the mast. The first, carriage 110 is the lower crowd. In various embodiments, lower crowd 110 travels along a pair of parallel tracks 105 running along the length of mast 100, enabling it to move along an axis defined by the orientation of the mast to drive screw anchors into the ground. Though not shown, in various embodiments, a fixed lower crowd motor is positioned near the lower end of the mast and is connected to drive chain 107 to selectively move lower crowd 110. Drive chain 107 extends substantially the entire length of mast 100. The lower crowd motor pulls up or down on lower crowd 110 providing downforce or up-force to rotary driver 115 attached to it. In addition, rotary driver 115 provides torque to the head of the screw anchor. During a screw anchor driving operation, a controller balances the downforce of the lower crowd motor with the output of the rotary driver to prevent the screw anchor from augering the underlying soil.

Above the lower crowd and rotary driver is second carriage 120 also known as the upper crowd. As shown, upper crowd 120 is a two-piece structure. The first piece 120A supports drill tool 125, which, in various embodiments, may be a hydraulic drifter capable of providing rotation and hammering force. Attached above drill tool 125 is the second piece 120B, that supports a separate drifter motor or upper crowd motor 130 that enables upper crowd 120, and by extension, drill tool 125, to move along mast 100 independent of the lower crowd and rotary driver. For example, as discussed in greater detail herein, in various embodiments, it may be desirable to dynamically extend drill bit 50 further ahead of the lower end of screw anchor 10 in response to a slowing or stalling of the driving operation. Additionally, once an anchor has been successfully driven to the target depth, it may be necessary to retract drilling tool 125 further up the mast so that shaft 30 of drilling tool 125 is out of the way of rotary driver 115 so that another screw anchor may be loaded.

Turning now to FIGS. 4A and 4B, these show views of a two-stage drill bit according to various embodiments of the invention. In FIG. 4A, bit 50 is shown in a first, loose soil mode. In FIG. 4B, it is shown in hard soil mode. The components in FIGS. 4A and 4B are best understood while also viewing exploded views of FIGS. 5A and 5B. Starting with 4A, in this mode, drill shift 30 and bit 50 are extended from above through screw anchor 10 while the anchor is being driven into the underlying ground. In various embodiments, shaft 30 and bit 50 are also rotated and extended out of the lower end of screw anchor 10 so that tip 75—in this case a drag bit—and a portion of shank 70 are clear of the open lower end of anchor 10 and able to cut a pilot hole ahead of it. In various embodiments, this may be a default mode of operation. In other words, the machine may attempt to drive the screw anchor into the underlying soil with the bit held at this orientation. Above bit tip 75 and shank 70 is a three-section assembly consisting of lower cutting portion 58, middle collar portion 56 and upper plunger portion 52. In various embodiments, tip portion 70 may be welded to the lower end of the lower cutting portion. In other embodiments, bit tip 75 may be threaded onto shank 70. Also, in various embodiments, middle collar portion 56 and lower cutting portion 58 may be welded together since they do not need to move relative to one another. Upper plunger portion 52 includes am upper opening that receives the tool or drill shaft 30. This may include threads (conventional or frustoconical) or a pin connection to shaft 30.

In various embodiments, upper plunger portion 52 is movable between two different positions, one where it is extended away from middle collar portion 56, as shown in FIG. 4A and one where it is flush against middle collar portion 56 signifying that the cutting wings of the lower cutting portion have deployed. In various embodiments, this is achieved by advancing drill shaft 30 and bit 50 further ahead of the open lower end of screw anchor 10 so that cutting wings 60 may splay outward. As shown in greater detail in FIG. 5B, this removes the resistance against the cutting wings from the inside surface of anchor 10, allowing allows the plunger to plunge down against middle collar portion, pushing against a pair of pins that in turn contact respective cutting wings 60 causing them to splay outwards and resulting in a wider bore than is possible with drag bit 75 alone. This geometry allows the drill to be selectively operated in one of two possible modes, resulting in different drill bore diameters, depending on the extent that the drill shaft is extended relative to the open lower end of the screw anchor. In various embodiments, and as discussed in the context of FIGS. 6 and 7, this transition between modes may occur automatically based on information from one or more real-time sensors monitored by the machine controller.

With continued reference to FIGS. 5A-B, these figures provide partially exploded views of a portion of drill bit 50. It should be appreciated by those of ordinary skill in the art that the specific deployment mechanism for cutting wings 60 is exemplary only and that various other mechanical structures maybe used, including intermediate structures that prevent pressure by the pistons against the piston contacts until the cutting wings have cleared the open lower end of the screw anchor so as not to damage the inside surface of the screw anchor while drilling in the first mode.

The first element shown in 5A is the upper plunger portion 52. During use, this portion is attached to the distal end of the drill shaft. In some cases, shaft 30 may have a thread form at its end. In others, upper plunger portion 52 may receive a locking pin or other structure to selectively couple it to the end of shaft 30. Though not visible in the figure, the recess in the top end of upper plunger portion 50 that receives the end of the drill shaft terminates part of the way into the body. Beyond that point, a narrower passage, preferably, though not necessarily through the center of upper plunger portion 52 extends through plunger shaft 53 to allow pressurized air from the shaft to be communicated through the bit. The outside of the upper plunger portion 52 has debris channels carved into to facilitate the removal of spoils during a drilling operation. The lower end of the upper plunger portion 52 consists of plunger shaft 53 that extends down and away from the upper end terminating in ring 55. In various embodiments, this portion is formed of a circular uniform diameter cylinder. As shown, it includes a series of alignment guides 54 that direct penetration into the subsequent middle collar portion 56 and prevent the upper plunger portion 52 from spinning independent of middle collar portion 56.

The next portion of the drill bit assembly 50 is middle collar portion 58. In various embodiments, plunger shaft 53 of upper plunger portion 52 extends all the way through middle collar portion 56 until it projects some distance out of the lower end. Guides 54 are received into corresponding slots formed in the inside surface of the upper end middle collar portion 56, allowing upper plunger portion 52 to selectively move towards and away from middle collar portion 56. In various embodiments, retaining ring 55 is welded onto the lower end of plunger shaft 53 only after it is passed completely through middle collar portion 56. This will limit the extent of movement of the lower two portions of the bit assembly relative to upper plunger portion 52 while preventing them from separating.

The next portion of the bit assembly 50 is the lower cutting portion 58. This portion continues the external shaft of the two preceding portions 52, 56 and also includes extensions of the debris channels that run along the outer surface of those portions. As shown, lower cutting portion 58 includes a pair of opposing hinged cutting wings 60. Cutting wings 60 are attached to a hinge shaft 65 that passes completely through the body of lower cutting portion 58. In the retracted position, such as that shown in FIG. 4A, wings 60 have a diameter that is less than the outside diameter of the rest of drill bit assembly 50. In the extended position, such as that shown in FIG. 4B, wings 60 splay outward widening the bore of drill bit assembly 50 beyond the outside diameter of the remainder of the bit. As shown, recesses are cut into the outside body of the lower cutting portion to receive the cutting wings so that their thickness does not increase or substantially increase the width of the bit relative the other portions. Shank 70 projects away from the bottom end of lower cutting portion 58. In some embodiments this shank may be threaded so as to receive bit or bit tip 75, such as the drag bit shown in FIGS. 4A/B.

In the example shown in FIGS. 5A and 5B, movement of cutting wings 60 is effected as follows. When the drill is operated, the bit rotates, and downforce is applied to the shaft which in turn is translated to the bit. As long as the position of the bit assembly relative to screw anchor 10 is maintained as shown in FIG. 4A, plunger shaft 53 is unable to move the piston 66 (see FIG. 5B) due to resistance from the inside of the screw anchor against the resisting surface 63 of each cutting wing. In various embodiments, surface 63 may be shaped to be bulbous so as to minimize damage to the inside of the screw anchor. Once the drill is advanced relative to the screw anchor such as that shown in FIG. 4B, resistance against expansion of the wings is limited only by the soil. Very quickly, the downforce from plunger shaft 53 against piston 66 will push against the piston contact surface 67 on each cutting wing, causing it to splay outward. As the bit assembly rotates, the bore hole diameter will increase due to the wider diameter of the extended cutting wings. It should be appreciated that in 5B, only a single piston is shown. One of the cutting blades and its corresponding piston have been removed to illustrate the deployment mechanism behind it.

Turning now to FIG. 6, this figure shows a functional block diagram of exemplary system 180 for two-mode drilling with the bit shown in FIGS. 4A-4B and 5A-5B according to various embodiments of the invention. The brain of the system is a controller, microcontroller or PLC 181 labeled as “μ” in the figure. In various embodiments controller 181 is a general or specific purpose microcontroller such as any of the various programmable logic controllers, microprocessors and/or integrated circuits available commercially. Controller 181 is coupled to sensor array 182 that provide real time information about the driving operation to the controller. Also, controller 181 is communicatively coupled to lower crowd motor 183, rotary driver 184, drill tool 185, upper crowd motor 186, and compressed air system 187, all which may be utilized by the controller to perform a drill assisted screw anchor driving operation. The compressed air system 187 may be separately controllable by drill tool 185 or may be controlled by controller 181 through drill tool 185. As discussed herein, in various embodiments, controller 181 includes non-volatile storage executes a control program that regulates the speed and/or force of these components to successfully drive a screw anchor to depth without augering or blowing out the hole. Sensors 182 may be coupled to the outputs of compressed air system 187, rotary driver 184, lower crowd motor 183, drill tool 185, and upper crowd motor 186. Sensors 182 may include one or more rotary and/or linear encoders that provide information to controller 181 to enable it to, for example, calculate a current rate of penetration of the screw anchor.

In the context of this disclosure, controller 181 may receive real-time information from one or more of the sensors indicative of the torque or force applied to the drill tool, and/or the current rate of penetration, and use this information to determine if the drill needs to be switched to a different mode. As discussed herein, in various embodiments, the controller may operate the drill tool in the mode shown in FIG. 4A by default. If, based on the sensor data, the drive operation is slowing or stalling, or torque or other forces are outside of acceptable limits, the controller may momentarily pause the rotary driver and lower crowd or simply activate the upper crowd to cause the tip of the drill bit assembly to extend further out of the lower end of the screw anchor so that the cutting wings are released from the screw anchor and able to widen the bore hole. The widened bore hole should allow the screw anchor to be driven with less effort and reduce required torque on the bit tip cutting the pilot bore ahead of the anchor. By continuing to monitor progress, the controller may revert back to the default mode based on sensed data to prevent a blow out or compromising the holding strength of the screw anchor, as necessary.

Turning now to FIG. 7, this figure shows flow chart 190 detailing the steps of a method for two-mode drilling while driving with a drill bit according to various embodiments of the invention. The method begins at step 191 driving while drilling operation commences. As discussed herein, this involves rotating the mast to the desired drilling angle and actuating the lower crowd and rotary driver to begin driving the screw anchor into the ground along the chosen drilling axis. In various embodiments, the upper crowd moves the drill shaft and bit down until the bit extends slightly out of the open lower end of the screw anchor. Then, the upper crowd motor releases the drive chain allowing the lower crowd to pull the rotary driver and drilling tool down at the same rate. In step 192, as driving continues with rotation and downforce of the anchor and rotation and downforce of the drill shaft and bit, the controller monitors real-time data (performance metrics) from one or more sensors taking data from the output of one or more of the rotary driver, drill tool, lower crowd motor and/or linear or rotary encodes. In step 193, based on the monitoring, a determination is made as to whether or not a change is needed one of the operating parameters controlling those performance metrics. For example, if the step of monitoring reveals that the operation has stalled, slowed down to an unacceptable level, or if the drilling tool or rotary driver are exerted forces outside of acceptable limits the controller may decide at step 193 that a change is needed. If so, operation continues between steps 192 and 193. Otherwise, if in step 193 it is determined that a change is needed, the controller causes the drill state to change, such as moving from the orientation shown in FIG. 4A to the orientation in 4B. This will allow the cutting wings of the bit to escape the screw anchor and begin widening the bore hole which should make the driving operation go more easily. In this way, the controller may automatically adjust back and forth between the two modes of drilling in a using feedback control without an operator needing to manually control it.

Turning now FIGS. 8A-C, these figures show different views of an expanding drill bit for use in a drilling while driving operation according to various embodiments of the invention. As shown, here, bit 200 has a hollowed, slightly elongated body 204 with upper end 201 and opposing lower end 207. Upper end 201 includes a threaded opening 202 that receives a threaded distal end of the drill or other tool shaft. In some embodiments, opening 202 may have frustoconical threads while in others standard threads may be used. The outside of the body 204 is fluted with channels 206 for removing drilling debris known as spoils. In various embodiments, pressurized air passes through body 204 via the threaded opening 202 at upper end 201 and is vented out proximate to lower end 207 where spoils are generated, pushing them through the channels ad out of the way of cutting wings 210.

Lower end 207 of bit 200 has a pair of cutting wings 210 that are hinged about a hinge pin 220 that passes orthogonally through main body 204. Cutting wings 210 include cutting surfaces 213 on their lower bottom edge and outer edge 214. In various embodiments, cutting wings 210 are able to move between a fully retracted orientation (see, e.g., FIG. 10B), having a minimized outside diameter and a fully expanded orientation (see, e.g., FIG. 10A), having a maximized outside diameter. In various embodiments, when bit 200 has exited the lower end of the screw anchor and is subjected to downforce via the drill shaft, the resistance from the soil or rock on the lower surface 214 of each wing 210 causes it to splay outward maximizing its diameter. By contrast, when bit 200 is pulled back into the shaft of a driven screw anchor, or inserted into it, wings 210 may collapse inward towards one another allowing it to fit within the inside diameter of the screw anchor. In various embodiments, and as shown in greater detail in the context of FIGS. 9A and 9B, a bifurcated wing spring 230 concealed within body 204 may provide resistance to the wings, tending to keep them splayed out.

As seen in FIGS. 8B and 9A, a midline through main body 204 shows that the lower contact surfaces 214 on each cutting wing, is angled down and away from the approximate midline. This insures that when the lower end of the bit engages resistance when driven into the downward or axial direction, the angled lower surfaces will try to achieve a flat rather than sloped orientation, causing the cutting blades to splay outward, widening the bore made by the bit. 1C is a bottom view of the bit

Turning now to FIGS. 9A and B, these figures are exploded views of bit 200 shown in FIGS. 8A-C. Starting with 9A, in this figure all of the components of bit 200 are exploded away main body 2-4. Starting at the top, the top end of a wing spring 230 is pressed into a slot formed in a tubular, hollow spring retainer 231. Retainer 231 is then passed through opening 204 in upper end 201 of body 204 with the lower, bifurcated end of wing spring 230 leading. After passing the threads, the opening through center of the body narrows to be only about the same as outside diameter of spring retainer 231. This narrower opening functions as an air channel to communicate pressurized air from the drill shaft. Retainer 231 may be pressed into the air channel formed in the body with a press or die. At lower end 207, hinge pin 216 is passed orthogonally through body 204, passing first through one of cutting wings 210, then completely through the body and through second cutting wing 210. Hinge pin 216 has a hole passing entirely through it that is aligned with the air passage through the body when fully inserted to receive the bifurcated end of the wing spring 230 and retainer 231. In various embodiments, spring retainer 231 is pressed down until it contacts hinge pin 216 proximate to this hole. In various embodiments, a retaining clip or C-clamp such as C-clip 217 is pressed around the leading edge of pin 216 to retain it in place when it comes out the other side of the body and passes through the second cutting wing. As shown, hinge pin 216 may have a through hole passing through its middle that receives set screw 232 passing through the body to prevent rotation of the pin.

FIG. 9B, shows in greater detail the fitment between wing spring 230, spring retainer 231 and hinge pin 216. The spring retainer is pressed into the passage within the body until the wider top end of the wing spring is pressed against the surface of the hinge pin. The narrower fingers of spring 230 pass down through pin 216, extending down through the body where they have room to deform in response to pressure from one of the cutting wings when the cutting wings are compressed inward toward one another (i.e., in the retracted position).

FIGS. 10A-C show three stages of cutting wing deployment: the two extreme cases of fully deployed and fully retracted in 10A and 10B respectively, and an intermediate case where no contact forces are acting on the cutting wings, causing them to hang under the force of gravity, just contacting wing spring without deforming it (FIG. 10C). Starting with 10A, in this figure cutting wings 210 are fully deployed, that is, at their maximum outside diameter. At this orientation, the first upper contact surface 212 of each wing acts as a stop to the limit the extent of outward rotation when that surface strikes a corresponding surface on the body of the bit. The bottom surface 214 of each cutting wing is in a substantially common plane. This may also be seen in the partial cut-away view of FIG. 11A where the bifurcated end of wing spring 230 is seen in the middle of the body, uncontacted by cutting wing 210. This orientation occurs automatically when downforce is applied to the drill shaft and the lower end 214 of wing 210 encounters resistance seeking to flatten the geometry of the bottom surface of each cutting wing. Once that axial downforce is removed, such as when the target depth is reached and bit 200 is withdrawn, the force splaying the wings is eliminated and the cutting wings are free to retract.

FIG. 10B shows the opposite case where cutting wings 210 are fully retracted towards one another. As discussed herein, this position is resisted by fingers of wing spring 230, resulting in their maximum deflection. At this position, rotation, and therefore, wing spring deformation, is limited by second upper contact surface 211 on each wing cutter as that surface contacts another corresponding surface on the bit's body. The partial cut-away view of FIG. 11B shows the cutting wing rotated inward, deflecting one finger of the bifurcated wing spring through contact with inner surface 215. Because this position requires biasing wing spring 230, it can only be maintained by applying continuous force to the edge 215 of cutting wings 210, such as, for example, when the bit is manually fed into the upper end of a screw anchor during loading, or withdrawn up into the lower end of a driven screw anchor after the target embedment depth has been reached.

FIG. 10C shows a natural position of the cutting wings, where gravity causes wings 210 to simply hang down. At his orientation, neither the first nor second upper contact surfaces 212, 211 are contacting body 214 and the inner bias surface 215 of each cutting wing 210 may merely contact the respective fingers of the bifurcated wing spring 230 without deforming them.

Turning to FIG. 12, this figure shows screw anchor 10 being driven with the drill assistance according to various embodiments of the invention. In this figure, details of the driving machine have been intentionally omitted. Screw anchor 10 shown here is driven at an angle with a combination of rotational torque and downforce transferred to the head of the anchor via a rotary driver. At the same time, drill rod 30 has been passed through the rotary driver and screw anchor 10 until bit 200 emerges from the open lower end. In various embodiments, the rotary driver and drill tool may be mounted on separate crowds that travel on a common mast of a screw anchor driving machine. In other embodiments they may travel together. The drill tool may be hydraulic drifter or other suitable drilling tool. In various embodiments, the drill may be inserted into the underlying ground at a different rate of feed and speed than the screw anchor and may extend only slightly out of the lower open end depending on soil conditions. Also, in some cases it may be necessary to withdrawal the drill rod and drag bit 200 from a partially driven screw anchor and to replace it with a with a tri-cone or button rock bit that uses a combination of rotation and hammering to drill a cavity for the screw anchor. Once the target depth is reached, the rotary driver is decoupled from the head of the screw anchor and the rotary driver and drill tool are withdrawn until the top end of the screw anchor is cleared.

It should be appreciated that although bits 50 and 200 are shown as drag-style bits the principles disclosed herein are applicable to button-style hammering bits that operate in two-stages or that including expanding wings. In such cases the wings of the bit will be replaced with beefier ones that support one or more carbide buttons and the drag bit features will be replaced with buttons.

The embodiments of the present inventions are not to be limited in scope by the specific embodiments described herein. Indeed, various modifications of the embodiments of the present inventions, in addition to those described herein, will be apparent to those of ordinary skill in the art from the foregoing description and accompanying drawings. Thus, such modifications are intended to fall within the scope of the following appended claims. Further, although some of the embodiments of the present invention have been described herein in the context of a particular implementation in a particular environment for a particular purpose, those of ordinary skill in the art will recognize that its usefulness is not limited thereto and that the embodiments of the present inventions can be beneficially implemented in any number of environments for any number of purposes. Accordingly, the claims set forth below should be construed in view of the full breath and spirit of the embodiments of the present inventions as disclosed herein.

Claims

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.