TABLE BUSHING LIFTING RING

Description

RELATED APPLICATION DATA

This application claims priority of U.S. Provisional Application No. 63/697,454, filed Sep. 21, 2024, which the entirety thereof is incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a table bushing lifting ring for drill bit or hammer changing.

BACKGROUND

Mobile drill rigs are commonly used in surface mining operations. Surface mining requires drilling patterns of holes to specific depths and angles into the drill bed. Self-propelled rigs preliminarily drill these holes. Later, the mine uses sequences of explosive charges to break up the bedrock (or other subsurface constituents) so that the large end loaders or drag lines can scoop up the material to transfer to dump trucks for relocation to the processing areas at the mine.

Many of the operations involved in servicing and maintaining the rigs are difficult and hazardous. Finding ways to automate these processes can, not only result in a machine that is easier to maintain, but also reduce cost and increase efficiency. One such task is replacing the rotary drill bit.

The current process for changing out bits is done manually with a mechanic and an operator. However, the leading standard today in drill rig technology is automation. Customers and suppliers would like to reduce the need for operators of the drill rig to increase safety and efficiency. Many tasks performed by the above type of drill rig have been successfully automated, however, automation of changing a drill bit has been attempted but has proven difficult to perfect.

Automating the process is needed in order to keep moving forward with the growing needs of the industry. By using the process of automated bit replacement, time can be drastically reduced and a faster, more reliable mechanism to change bits ultimately will save money. It will also improve the safety and eliminate potential bodily injury to the mechanic and/or the operator by eliminating the need for human interaction with the heavy drill bits.

In order to do so the table bushing that is used to centralize the drill pipe over the hole during drilling needs to be lifted out of the way when changing the bit. If it is desired to automate the bit changing process then removal and reinstalling of the table bushing also needs to be automated.

One hindering factor towards automating bit changing is the existing solution where the table bushing is manually installed to the drill string every time a bit is changed. See FIGS. 1A and 1B. In this manner, a weldment is manually installed to the drill pipe. Pins hold the table bushing to the weldment and the weldment is held to the drill pipe via flats thereon. The drill pipe is then lifted with the rotary head and the table bushing is picked up also. However, the presence of the weldment and table bushing limits access to the drill bit to be changed and as such the automatic changing of the drill bit is hindered. Thus, this conventional manual process is not feasible in a situation where the process needs to be automated.

Thus, there is the need for a solution whereby the table bushing can be automatically lifted out of the mast table when the drill string retracts.

SUMMARY

In one embodiment a table bushing lifting ring is provided to improve a drill bit changing process.

The table bushing lifting ring is arranged for use with a drill string having a bit sub. The table bushing lifting ring includes an annular body having an inner diameter sized to receive the drill string therethrough; a lower surface configured to engage with a step formed on the bit sub; an upper surface configured to engage with a lower surface of a table bushing; and a plurality of flanges formed at a periphery of the annular body, wherein the flanges extend radially outward beyond a diameter of the step on the bit sub.

In yet another embodiment a drill string incorporating a table bushing and table bushing lifting ring is provided.

The drill string assembly includes a drill string including a drill pipe, a bit sub connected to the drill pipe, the bit sub having a step formed thereon, a drill bit threadedly engaged to the bit sub, a table bushing having a tubular configuration with an opening sized to receive the drill string, the table bushing including a rim at a top end and a lower surface at an opposed end, and a table bushing lifting ring positioned on the step of the bit sub, wherein the table busing lifting ring is configured to lift the table bushing out of a deck aperture when the drill string is retracted.

In still another embodiment, a method for lifting a table bushing in an automated drill bit changing process is provided.

The method for automatically lifting a table bushing during a drill bit changing process includes providing a drill string having a bit sub with a step formed thereon; positioning a table bushing lifting ring on the step of the bit sub, the lifting ring including a plurality of flanges extending beyond a diameter of the step; lowering the drill string such that a table bushing positioned on the drill string is received within a deck aperture; separating the lifting ring from the table bushing as the drill string continues to be lowered; retracting the drill string such that the lifting ring reconnects with the table bushing; and lifting the table bushing out of the deck aperture via engagement between the flanges of the lifting ring and the table bushing.

An automated bit handling mechanism is positioned on a deck, the automated bit handling mechanism being slidably supported on the deck to move between a standby position during the lowering step where the mechanism is not centered with the drill bit or drill pipe and the deck aperture is not covered by the automated bit handling mechanism and an engaged position where the deck aperture is covered and the automated bit handling mechanism is centered with the drill bit or drill pipe.

The foregoing summary, as well as the following detailed description of the embodiments, will be better understood when read in conjunction with the appended drawings. It should be understood that the embodiments depicted are not limited to the precise arrangements and instrumentalities shown.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B are prior art weldments for installing drill pipe.

FIG. 2 is schematic view of a mobile drill rig.

FIG. 3 is an exploded, schematic view of a drill string in accordance with the present disclosure.

FIG. 4A is an enlarged perspective view of the bit sub, table bushing and table bushing lifting ring according to the present disclosure.

FIG. 4B is a cross-sectional view of FIG. 4A.

FIG. 5 is a side perspective view of the bit sub and table bushing lifting ring according to the present disclosure.

FIG. 6 is a perspective view of the table bushing of the present disclosure.

FIG. 7 is a perspective view of the table bushing lifting ring according to the present disclosure.

FIG. 8 is a perspective view of a deck wrench assembly and bit changer mechanism assembly.

FIGS. 9A-9C illustrate the drill bit and bit sub with the table bushing and table bushing lifting ring thereon being lowered according to the present disclosure.

FIGS. 10A-10C illustrate the drill bit and bit sub with the table bushing and table bushing lifting ring thereon being retracted according to the present disclosure.

FIGS. 11A-11C are cross-sectional views of the table bushing, table bushing lifting ring and bit sub in relation to the deck wrench assembly during the retraction process of FIGS. 10A-10C.

DETAILED DESCRIPTION

As shown in FIG. 2, a mining vehicle 10, such as a rotary drill rig, includes a mobile deck or carriage 12 having a frame and a mast 14 mounted on the carriage. Mining vehicle 10 can be down-the-hole (DTH) drill rig or a rotary blasthole drill rig. It should be appreciated that other types of vehicles are contemplated and the present disclosure is not limited to mining vehicles or a particular type of mining vehicle.

Mast 14 is movable between a horizontal, stored position and a vertical position as shown. The mast carries a rotary head 16 which is capable of rotating a drill string 18 to which a drill bit 20 is mounted. The rotary head 16 can be raised and lowered to enable pipes to be removed or added to the drill string. Moreover, rotary head 16 operates to lower and retract the drill string as herein described.

It should be appreciated that a control unit can be located on the rig and arranged to control the various components of the present drill rig, such as the rotary head, and drill bit lowering and retraction process. The control unit can be a computer, processing device, or any corresponding device and may include a user interface with a display device as well as control means for giving commands and information to the drill bit changer system. The control unit may be a computer equipped with appropriate software that can be accessed and controlled by the operator of the drill rig. Additionally, the control unit can be operated remotely.

As shown in FIG. 3, drill string 18 can be a drill pipe 19 with a top sub 24 engaged at a top end thereof and a bit 20 threadedly engaged at a bottom end of a bit sub 22 of the drill string. Bit sub 22 is a short section of the drill string that connects the drill bit to the rest of the drill pipe/string.

As will be described further herein, a table bushing 26 is supported by a table bushing lifting ring 28 that is located on top of bit sub 22. Table bushing 26 helps to centralize the drill string in the deck opening and adds support to the drill string during the drilling processes.

FIGS. 4A-5 show the assembly arrangement of table bushing 26, lifting ring 28 and bit sub 22 in more detail. Referring to FIG. 5, a step 36 is machined into bit sub 22 to support table bushing lifting ring 28. Adding a ring to slide over the top of the bit sub that will lift and support the bushing as the drill string retracts requires step 36 to be machined to act as a shoulder on the top of the bit sub for the lifting ring to rest. Thus, table bushing ring 28 will lift table bushing 26 out of the mast deck/table when the drill string retracts.

As shown in FIG. 6, table bushing 26 is formed as a tubular member having an opening 37 and which is sized to receive the drill string. Table bushing 26 includes a rim 38 at a top end and a lower surface 39 at an opposed end. Table bushing 26 can be a single piece as illustrated herein or made of multiple connected parts.

FIG. 7 illustrates table bushing lifting ring 28 in further detail. As shown, lifting ring 28 is an annular body 29 having an opening 31 and opposed ends. The annular body has an inner diameter sized to receive the drill string therethrough. Lifting ring 28 includes a plurality of flanges 30 formed at a periphery thereof at an upper surface 34. Referring again to FIGS. 4B and 5, the diameter D of lifting ring 28 is equal or less than a diameter of step 36 of the bit sub 22. However, flanges 30 extend beyond diameter D and step 36. Thus, the flanges extend radially outward beyond a diameter of the step on the bit sub.

Table bushing lifting ring 28 has upper surface 34 and a lower surface 32. Lower surface 32 engages with step 36 of bit sub 22 which extends therethrough and upper surface 34, especially at flanges 30 engages with lower surface 39 of table bushing 26.

Table bushing lifting ring 28 can be made of a hardened material and can include carbide inserts or subject to case hardening. Moreover, upper surface 34 and lower surface 32 can be tapered, for example, a 30° taper on the top and a 45° taper on the bottom.

Table bushing lifting ring 28 is arranged to be replaceable, either by itself or with other components, such as the bit sub. However, by having the ring solely replaceable, less cost and rig downtime for maintenance is achieved.

FIG. 8 illustrates an automated combined deck wrench and bit handling mechanism, which the present table bushing lifting ring is intended to coordinate with. As shown, bit handling mechanism 40 is movably mounted on deck wrench assembly 42, which is mounted on deck 43 of mast 14 of the drill rig. As described herein, table bushing 26, which is mounted on drill string 18, is accommodated within deck aperture 44, which is aligned with a corresponding opening of the deck when the drill string is lowered and retracted.

The automated bit handling mechanism is arranged to carry new and used bits and although it will not be further described, bit handling mechanism 40 is slidably supported on deck wrench assembly 42 to move between the standby position where the mechanism is not centered with the drill bit or drill pipe and aperture 44 of the deck wrench is not covered by mechanism 40 and an engaged position where aperture 44 is covered and mechanism 40 is centered with the drill bit or drill pipe. Thus, the position of table bushing 26 within aperture 44 is coordinated with retraction and lowering of the drill string and position of mechanism 40.

FIGS. 9A-9G illustrate the drill string/bit lowering process according to the present disclosure. In the first step shown in FIG. 9A, table bushing 26 is positioned on the drill pipe along with support ring 28. The drill string is centered over aperture 44. In step 8B, the drill string/bit is lowered so that table bushing 26 is positioned within aperture 44 as described above. As shown in FIG. 8C, the drill string/bit continues to be lowered with table bushing 26 remaining in aperture 44 of the deck. Lifting ring 28, which is supported on the bit sub separates from table busing 26 and continues to move downward with the bit sub.

FIGS. 10A-11C illustrate the bit retraction process according to the present disclosure, with FIGS. 11a-11c illustrating the process in detailed cross-section. FIGS. 10A and 11A show the drill string/bit in the lowered position prior to start of retraction of the drill string. As shown, table bushing 26 extends through aperture 44 and the bit changing mechanism 40 is in a standby position.

FIGS. 10B and 11B illustrate the beginning of retraction of the drill string/bit. As illustrated, bit sub 22 begins to move upward through the mast deck and lifting ring 28 once again connects with the table bushing 26.

As shown in FIGS. 10C and 11C, the lifting ring, which is supported on step 36 of the bit sub and travelling with the drill string lifts the table bushing upward and out of deck aperture 44. At this point, the bit changing mechanism is able to be moved into an engaged position whereby the drill bit can be lowered to remove the existing drill bit and place a new bit onto the drill string.

It should be appreciated that although reference is made that the present process is described for the application with an automated drill bit changing process, its use with other processes, such as changing out a hammer or other components is contemplated.

Although the present embodiment(s) has been described in relation to particular aspects thereof, many other variations and modifications and other uses will become apparent to those skilled in the art. It is preferred therefore that the present embodiment(s) be limited not by the specific disclosure herein, but only by the appended claims.