Automatic Coupling System

Abstract

In an automatic coupling system, a threaded quill is connected to a rotating and advancing mechanism by a slip coupling and is biased toward a drill pipe by a spring. In the use of the system, the quill is advanced toward the drill pipe and is simultaneously rotated with respect to the pipe. When the quill engages the pipe, it slips relative to the advancing and rotating mechanism against the action of the spring until a quill advance terminating switch is closed. The rotation of the quill is continued until the torque on the quill reaches a predetermined limit.

Description

BACKGROUND OF THE INVENTION

In the drilling industry, drilling machines or rigs are employed to form oil wells and similar deep boreholes. As opposed to conventional rigs, automatic drilling machines perform the various steps involved in forming a borehole without human intervention. Typically, this is accomplished by means of a drill head mounted in a drilling tower for vertical movement by hydraulic cylinders connected to the top of the tower.

In the use of an automatic drilling machine, the drill head is connected to a drill bit through a string of drill pipe. The drill head rotates the drill string and the drill bit and thereby forms a borehole. As the depth of the borehole increases, new sections of drill pipe are added to the drill string. This is accomplished by disconnecting the drill head from the drill string, operating the hydraulic cylinders to raise the drill head to the top of the tower, connecting a new section of pipe to the drill head, and then connecting the new section to the drill string.

Heretofore, the connection of the drill head to a new section of drill pipe has been a relatively slow operation, even in an automatic drilling machine. This is because the drill head is connected to the pipe through a quill that is threadably engaged with the upper portion of the pipe. In order to threadably interengage the quill and the pipe, it has heretofore been necessary to rotate and advance the quill in accordance with the lead of the threaded connection.

This invention relates to a method and apparatus whereby the drill head of an automatic drilling machine is attached to a section of drill pipe in a rapid and efficient manner. The use of the invention permits the automatic connection of the drill head to a section of drill pipe without danger of jamming or mutilating the threads of either the pipe or the quill, and without the necessity of accurately positioning the pipe. Furthermore, the use of the invention eliminates the application of excessive torque loads to the threaded connection between the quill and the pipe, and thereby facilitates the subsequent removal of the quill from the pipe.

SUMMARY OF THE INVENTION

In accordance with the preferred embodiment of the invention, an automatic coupling system includes a threaded member that is simultaneously advanced and rotated. The advance of the threaded member continues until the threaded member contacts another threaded member. Rotation continues until a threaded connection is formed. Preferably, the threaded member is spring biased and is rotated until a predetermined torque is applied between the threaded members.

DESCRIPTION OF THE DRAWINGS

A more complete understanding of the invention may be had by referring to the following detailed description when taken in conjunction with the drawings, wherein:

FIG. 1 is an illustration of an automatic drilling machine including an automatic coupling system employing the present invention;

FIG. 2 is an enlarged sectional view illustrating the automatic coupling system of the automatic drilling machine shown in FIG. 1, and

FIGS. 3, 4 and 5 are illustrations of various steps in the operation of the automatic coupling system.

DETAILED DESCRIPTION

Referring now to the drawings, and particularly to FIG. 1 thereof, there is shown an automatic drilling machine 10 including an automatic coupling system 12 employing the present invention. The automatic drilling machine 10 includes a platform 14 having a tower or mast 16 mounted on it. The tower 16 extends upwardly from the platform 14 and supports a plurality of hydraulic cylinders 18. The tower 16 also supports a drill head 20 which is mounted for reciprocation in the tower 16 upon operation of the hydraulic cylinders 18.

In the use of the automatic drilling machine 10, the drill head 20 is connected to a drill string 22 which extends to a drill bit (not shown). The drill head 20 rotates the drill string and the drill bit and thereby forms a borehole. As the formation of the borehole progresses, the drill head 20 moves downwardly relative to the tower 16 of the automatic drilling machine 10.

When the drill head 20 reaches the position shown in FIG. 1, it is disconnected from the drill string 22 and is raised relative to the tower 16 by the hydraulic cylinders 18. When the drill head 20 is at the top of the tower 16, a new section of drill pipe is positioned under the drill head 20 and the automatic coupling mechanism 12 of the present invention couples the drill head 20 to the new section of drill pipe. The new section of pipe is then connected to the drill string 22, and the drill head 20 is again operated to rotate the drill string 22 and the drill bit.

Referring now to FIG. 2, the automatic coupling system 12 of the automatic drilling machine 10 is shown in detail. The system 12 includes an outer sleeve 24 which is coupled to a drive tube 26 that extends downwardly from the drill head 20. An inner sleeve 28 is secured to the outer sleeve 24 by a plurality of screws 30, and a retaining collar 32 is threadably engaged with the distal end of the outer sleeve 24. A compression spring 34 is mounted between the inner sleeve 28 and the outer sleeve 24.

In addition to the sleeves 24 and 28 and the spring 34, the automatic coupling system 12 comprises a quill 36 having a threaded distal end 38. The quill 36 is mounted for sliding movement axially of the outer sleeve 24, but is prevented from rotational movement relative to the outer sleeve 24 by a spline connection 40. A packing nut 42 is secured between the quill 36 and the inner sleeve 28 by a retaining ring 44. The compression spring 34 extends into engagement with the retaining ring 44 and normally urges the threaded quill 36 into engagement with the retaining collar 32.

The automatic coupling system 12 further includes a quill advance terminating subsystem 46. The subsystem 46 includes a switch actuating plate 48 which is secured to the quill 36 by the cooperation of an annular projection 50 on the quill 36, a retaining ring 52 and a plurality of screws 54. A slider 56 is mounted adjacent the switch actuating plate 48 and includes a plate engaging roller 58. The slider 56 is mounted in a guide 60 that extends from the drill head 20 and is urged toward the position shown in FIG. 2 by a tension spring 62 connected between a tab 64 on the guide 60 and a tab 66 on the slider 56. A limit switch 68 is mounted on the drill head 20 for actuation by the slider 56 upon relative movement between the quill 36 and the drill head 20.

The operation of automatic coupling system 12 is illustrated in FIGS. 2, 3, 4 and 5. Referring first to FIGS. 2 and 3, a new section of drill pipe 70 is mounted beneath the drill head 20 of the automatic drilling machine 10 and is secured with respect thereto by a suitable chuck (not shown). Thereafter, the hydraulic cylinders 18 are operated to advance the automatic coupling system 12 toward the new section of pipe 70 and a motor and transmission assembly 72 is simultaneously actuated to rotate the quill 36 of the system 12 relative to the new section of pipe.

Referring specifically to FIG. 2, the motor and transmission assembly 72 is mounted on the drill head 20 and is coupled directly to the drive tube 26 thereof. The assembly 72 includes hydraulic motors that are driven by hydraulic fluid supplied by a pump 74 which is in turn driven by an engine 76. Preferably, the pump 74 and the engine 76 are mounted on a platform (not shown) positioned adjacent the drilling machine 10 and are connected to the motor and transmission assembly 72 by hydraulic piping. Hydraulic fluid for the hydraulic cylinder 18 of the automatic drilling machine 10 is supplied through a solenoid operated valve 78 by a pump 80 that is driven by an engine 82.

Referring now to FIGS. 3 and 4, the quill 36 of the automatic coupling system 12 is advanced toward the new section of pipe 70 and is simultaneously rotated with respect thereto until the threaded end 38 of the quill 36 engages the new section of pipe. Interengagement of the quill 36 and the new section of pipe 70 prevents further advance of the quill 36, but does not prevent further advance of the drill head 20 and the outer sleeve 24 connected thereto. Therefore, upon engagement with the new section of pipe, the quill 36 moves relative to the drill head 20 against the action of the spring 34.

As the quill 36 moves into the outer sleeve 24, the plate 48 engages the roller 58 of the slider 56 and thereafter moves the slider 56 upwardly in the guide 60 against the action of the spring 62. This action continues until the slider 56 engages the switch 68. Actuation of the switch 68 operates the valve 78 to terminate operation of the hydraulic cylinders 18. Thus, actuation of the switch 68 interrupts the advance of the drill head 20 and thereby terminates movement of the quill 36 relative to the drill head 20.

Actuation of the switch 68 does not terminate the rotation of the quill 36 under the action of the motor and transmission assembly 72. Rather, the rotation of the quill 36 is continued so that the threaded end 38 of the quill threadably engages the new section of pipe 70 under the combined actions of the motor and transmission assembly 72, which rotates the quill 36, and the spring 34, which urges the quill 36 toward the new section of pipe 70. Rotation of the quill 36 continues until a threaded connection is formed between the quill 36 and the new section of pipe 70 as determined by a torque monitor 84. The monitor 84 comprises a pressure sensitive switch that monitors the pressure in the line between the pump 74 and the hydraulic motors of the motor and transmission assembly 72 and that terminates the flow of hydraulic fluid to the motors when the load on the motors reaches a predetermined limit.

It will be understood that as the quill 36 is rotated into threaded interengagement with the new section of pipe 70, the quill 36 moves away from the drill head 20 under the action of the spring 34. In some instances, this action may move the slider 56 out of engagement with the limit switch 68. In such a case, the hydraulic cylinders 18 of the automatic drilling machine 10 are again actuated to advance the drill head 20 toward the new section of pipe 70. This action is terminated as soon as the slider 56 reengages the switch 68.

After the quill 36 is connected to the new section of pipe, the chucks that were engaged with the new section are released. Then the new section is connected to the drill string and the drill head is employed to rotate the drill string and drill bit. This action increases the depth of the borehole and is continued until the depth has increased about 30 feet whereupon the quill 36 is unthreaded from the drill string, and a new section of pipe is connected between the drill string and the drill head.

The automatic coupling system 12 of the automatic drilling machine 10 also plays an important role in the unthreading of the quill 36. Because of the spline connection 40 between the quill 36 and the drill head 20, it is not necessary to correlate the rotary and linear movement of the quill with the lead of the threaded connection. Rather, the quill 36 is simply rotated at high speed relative to the drill string. As the quill unthreads, it moves upwardly relative to the drill head against the action of the spring 34.

The use of an automatic coupling system employing the present invention in an automatic drilling machine results in several advantages over the prior art. First, when the present invention is employed, it is not necessary to accurately position a section of drill pipe relative to the drill head. That is, since the drill head is advanced until the quill engages the pipe, the pipe can be positioned virtually anywhere when the limits of travel of the drill head without consequence as to the operation of the automatic coupling system.

Second, the use of the present invention eliminates the necessity of correlating the advance and the rotation of the quill with the lead of the threaded connection. Instead, the advance and the rotation of the quill are completely independent and can be carried out at any desired speed. Usually, the quill is advanced much more rapidly than would otherwise be the case, and a threaded connection between the quill and a section of pipe is therefore formed much more quickly.

Third, when the present invention is utilized, the application of excessive torque loads between the quill and a section of pipe is prevented. This eliminates jamming and mutilation of threads. Also, the subsequent unthreading of the quill is facilitated when the initial torque on the threaded connection between the quill and a pipe section is held to a controlled limit.

Fourth, the automatic coupling system shown in the drawings facilitates the disconnection of the quill of an automatic drilling machine in that it eliminates the necessity of correlating the rotary and linear motions of the quill with the lead of the threaded connection during the unthreading of the quill. Thus, the use of the present invention increases the speed of both the coupling and the uncoupling of the quill.

Although only one embodiment of the invention is shown in the drawings and described herein, it will be understood that the invention is not limited to the embodiment disclosed, but is capable of rearrangement, modification and substitution of parts and elements without departing from the spirit of the invention.

Claims

What is claimed is:

1. An automatic coupling apparatus comprising:

a threaded member;

means for supporting and rotating the threaded member;

means for advancing the threaded member, and

means responsive to contact between the threaded member and another threaded member for automatically terminating the operation of the advancing means.

2. The automatic coupling apparatus according to claim 1 wherein the terminating means comprises:

means for moving the threaded member relative to the supporting and rotating means upon contact between the threaded member and another threaded member, and

means responsive to the predetermined amount of relative movement between the threaded member and the supporting and rotating means for terminating the advance of the threaded member.

3. The automatic coupling apparatus according to claim 2 wherein the means for moving the threaded member relative to the supporting and rotating means includes a slip coupling between the threaded member and the supporting and rotating means and means for biasing the threaded member into engagement with another threaded member.

4. The automatic coupling apparatus according to claim 1 wherein the supporting and rotating means supports the threaded member for movement between an extended position and a retracted position and means for biasing the threaded member toward the extended position.

5. The automatic coupling apparatus according to claim 4 wherein the terminating means includes means responsive to movement of the threaded member toward the retracted position against the action of the biasing means for terminating the advance of the threaded member.

6. The automatic coupling apparatus according to claim 1 further including means for terminating the rotation of the threaded member upon threaded interengagement between the threaded member and another threaded member.

7. The automatic coupling apparatus according to claim 6 wherein the rotation terminating means is responsive to the torque imposed on the threaded member by the supporting and rotating means.

8. An automatic coupling apparatus comprising:

a threaded quill;

means for positioning a drill pipe for threaded connection to the quill;

means for moving the quill into engagement with the drill pipe and for thereafter biasing the quill toward the drill pipe; and

means for rotating the quill relative to the drill pipe and thereby forming a threaded connection between the drill pipe and the quill.

9. The automatic coupling apparatus according to claim 8 further including means for terminating the rotation of the quill after the threaded connection is formed.

10. The automatic coupling apparatus according to claim 8 wherein the quill and the rotating means are mounted on a drill head and wherein the moving and biasing means moves the drill head toward the drill pipe.

11. The automatic coupling apparatus according to claim 10 further characterized by a spline coupling between the quill and the rotating means for permitting relative sliding motion therebetween while preventing relative rotation.

12. The automatic coupling apparatus according to claim 10 wherein the quill is mounted on the drill head for sliding movement with respect thereto and wherein the biasing portion of the moving biasing means comprises a spring mounted between the drill head and the quill for urging the quill into engagement with the drill pipe.

13. The automatic coupling apparatus according to claim 12 further including means for terminating the movement of the drill head toward the drill pipe in response to sliding movement of the quill relative to the drill head.

14. The automatic coupling apparatus according to claim 13 wherein the movement terminating means includes switch means mounted for actuation upon relative movement between the quill and the drill head.

15. A method of automatically coupling a threaded quill to a drill pipe comprising:

advancing a spring loaded threaded quill toward a drill pipe and simultaneously rotating the quill relative to the pipe;

engaging the quill with the drill pipe to compress the spring;

actuating sensing means to terminate the advance of the quill after a predetermined amount of compression of the spring, and

actuating sensing means to terminate the rotation of the quill relative to the drill pipe when the torque on the quill exceeds a predetermined level.

16. The method according to claim 15 wherein the advancing and rotating step includes the steps of:

positioning a drill pipe at a predetermined location, and

moving a quill rotating mechanism toward the predetermined location.

17. The method according to claim 16 wherein the terminating step includes the step of sensing relative movement between the quill and the rotating mechanism upon engagement of the quill with the drill pipe.

18. The method according to claim 17 wherein the rotation terminating step includes the steps of:

sensing the torque that is applied to the quill by the rotating mechanism, and

terminating the operation of the rotating mechanism when the torque applied to the quill exceeds the predetermined level.